ORIGINAL PAPER
The Neoproterozoic-early Paleozoic metamorphic and magmatic
evolution of the Eastern Sierras Pampeanas: an overview
Andre´ Steenken • Mo´nica G. Lo´pez de Luchi •
Carmen Martı´nez Dopico • Malte Drobe •
Klaus Wemmer • Siegfried Siegesmund
Received: 16 March 2010 / Accepted: 20 November 2010 / Published online: 30 December 2010
 Springer-Verlag 2010
Abstract The Eastern Sierras Pampeanas were structured
by three main events: the Ediacaran to early Cambrian
(580–510 Ma) Pampean, the late Cambrian–Ordovician
(500–440 Ma) Famatinian and the Devonian-Carbonifer-
ous (400–350 Ma) Achalian orogenies. Geochronological
and Sm–Nd isotopic evidence combined with petrological
and structural features allow to speculate for a major rift
event (Ediacaran) dividing into two Mesoproterozoic major
crustal blocks (source of the Grenvillian age peaks in the
metaclastic rocks).This event would be coeval with the
development of arc magmatism along the eastern margin of
the eastern block. Closure of this eastern margin led to a
Cambrian active margin (Sierra Norte arc) along the wes-
tern margin of the eastern block in which magmatism
reworked the same crustal block. Consumption of a ridge
segment (input of OIB signature mafic magmas) which
controlled granulite-facies metamorphism led to a final
collision (Pampean orogeny) with the western Mesopro-
trozoic block. Sm–Nd results for the metamorphic base-
ment suggest that the TDM age interval of 1.8–1.7 Ga,
which is associated with the less radiogenic values of
eNd(540) (-6 to -8), can be considered as the mean aver-
age crustal composition for the Eastern Sierras Pampeanas.
Increasing metamorphic grade in rocks with similar detrital
sources and metamorphic ages like in the Sierras de
Co´rdoba is associated with a younger TDM age and a more
positive eNd(540) value. Pampean pre-540 Ma granitoids
form two clusters, one with TDM ages between 2.0 and
1.75 Ga and another between 1.6 and 1.5 Ga. Pampean
post-540 Ma granitoids exhibit more homogenous TDM
ages ranging from 2.0 to 1.75 Ga. Ordovician re-activation
of active margin along the western part of the block that
collided in the Cambrian led to arc magmatism (Famatinian
orogeny) and related ensialic back-arc basin in which
high-grade metamorphism is related to mid-crustal felsic
plutonism and mafic magmatism with significant contam-
ination of continental crust. TDM values for the Ordovician
Famatinian granitoids define a main interval of 1.8–1.6,
except for the Ordovician TTG suites of the Sierras de
Co´rdoba, which show younger TDM ages ranging from 1.3
to 1.0 Ga. In Devonian times (Achalian orogeny), a new
subduction regime installed west of the Eastern Sierras
Pampeanas. Devonian magmatism in the Sierras exhibit
process of mixing/assimilation of depleted mantle signa-
ture melts and continental crust. Achalian magmatism
exhibits more radiogenic eNd(540) values that range
between 0.5 and -4 and TDM ages younger than 1.3 Ga. In
pre-Devonian times, crustal reworking is dominant,
whereas processes during Devonian times involved dif-
ferent geochemical and isotopic signatures that reflect a
major input of juvenile magmatism.
Keywords Magmatism-metamorphism 
Sm–Nd systematics  Tectonic evolution 
Neoproterozoic-early Paleozoic orogenies 
Eastern Sierras Pampeanas
A. Steenken
Geologisches und Geographisches Institut,
Universita¨t Greifswald, Friedrich-Ludwig-Jahn Strasse 17a,
17489 Greifswald, Germany
M. G. Lo´pez de Luchi (&)  C. Martı´nez Dopico
Instituto de Geocronologı´a y Geologı´a Isoto´pica (INGEIS),
CONICET-Universidad de Buenos Aires,
Pabello´n INGEIS, Ciudad Universitaria,
1428 Buenos Aires, Argentina
e-mail: deluchi@ingeis.uba.ar
M. Drobe  K. Wemmer  S. Siegesmund
Geoscience Centre of the University of Go¨ttingen,
Goldschmidtstr. 3, 37077 Go¨ttingen, Germany
123
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
DOI 10.1007/s00531-010-0624-0
Introduction
The Pacific margin of Gondwana is composed of different
cratonic blocks that were amalgamated during several
events from the Proterozoic to the Paleozoic (Rapela et al.
2007; Ramos 2008 and references therein). The Sierras
Pampeanas, which constitute a series of N–S-oriented
basement units cropping out between 26 and 33 S, are
situated between the Archaean to Palaeoproterozoic Rı´o de
la Plata craton to the east against which they have a fault
contact (Lo´pez de Luchi et al. 2005) and to the Grenvillian
Cuyania-Precordillera Terrane (Kay et al. 1996) in the
west.
The Sierras Pampeanas are separated into the Eastern
Sierras Pampeanas (ESP) dominated by Paleozoic granites,
metasedimentary and metaigneous rocks, and the Western
Sierras Pampeanas (WSP) characterized by metabasic,
ultrabasic and calc-silicate rocks which expose Mesopro-
terozoic crystalline basement (Casquet et al. 2001, 2006;
Vujovich et al. 2004).
The Eastern Sierras Pampeanas constitute polyphase
deformed basement units, which were structured by three
events: the Ediacaran to early Cambrian (580–510 Ma)
Pampean, the late Cambrian–Ordovician (500–440 Ma)
Famatinian and the Devonian-Carboniferous (400–350
Ma) Achalian orogenies (Acen˜olaza and Toselli 1981;
Rapela et al. 1998; Stuart-Smith et al. 1999; Steenken et al.
2006; Lo´pez de Luchi et al. 2007; Drobe et al. 2009, 2010;
Siegesmund et al. 2010). These orogenies are related to the
accretion of different terranes integrated into the proto-
Andean margin of Gondwana. The low to high-grade
metasedimentary successions of the Eastern Sierras
Pampeanas were considered as an extension of the very
low to low-grade Puncoviscana Formation (Drobe et al.
2009 and references therein) that is developed along the
Cordillera Oriental.
The aim of this contribution is to give an overview of
the geological features of the Eastern Sierras Pampeanas
with the main focus on the Sierras de Co´rdoba, San Luis,
and Chepes. We integrate available geological, geochem-
ical, and isotopic information to set time constraints on the
metamorphism and magmatism and to provide a summary
of the data that may support a revised model for the late
Neoproterozoic to early Paleozoic tectonic evolution of the
proto-Andean margin of Gondwana. Hence, the paleotec-
tonic scenario calls for a major rift event (Ediacaran)
dividing crustal blocks with Sm–Nd signature and pro-
ducing juvenile crust with subsequent evolution of (Cam-
brian) active margins reworking the same crust. In the
Ordovician, re-activation of active margins led to the
opening of an ensialic back-arc basin with mafic crust
production and significant contamination by continental
crust. In Devonian times, a new subduction regime was
installed west of the Eastern Sierras Pampeanas and mag-
matism involves a transient heat anomaly associated with
extensive melting of an enriched mantle source and prob-
ably of a crustal segment.
Geological background of the main basement units
of the Eastern Sierras Pampeanas
The Eastern Sierras Pampeanas extend from southern Salta
to the San Luis and La Pampa provinces (Fig. 1). The
eastern sector of these basement units is mainly affected by
the Pampean orogeny, which is characterized by late
Neoproterozoic sedimentation and Ediacaran to Cambrian
deformation, magmatism and metamorphism (Rapela et al.
2007; Siegesmund et al. 2010). The western sector is
dominated by the Famatinian orogeny, which is charac-
terized by Cambrian marine sedimentation and late
Cambrian to Ordovician magmatism (Sims et al. 1998;
Steenken et al. 2006). The Achalian orogeny overprints this
basement (Sims et al. 1998, Siegesmund et al. 2010). Post-
Pampean cooling of the basement domains in the Cambrian
to early Ordovician is related to imbrication and uplift
along different shear zones, while middle to late Silurian
K/Ar biotite ages register different stages of the exhuma-
tion (Steenken et al. 2010).
Sierras de Co´rdoba and Sierra Norte
The Sierras de Co´rdoba and the Sierra Norte (Fig. 2), as
well as its continuation in the Sierras de Ambargasta and
Sumampa, are the easternmost group of the Sierras
Pampeanas. These Sierras consists of a series of north–
south mountain chains limited by west-vergent reverse
thrust faults on its western side and are separated by
intermontane Mesozoic and Cenozoic sediments (Table 1).
The Sierra Norte, Sierras de Ambargasta and Sumampa,
constitute a major block mostly made up of Ediacaran to
early Cambrian arc-related I-type calc-alkaline granitoid
intrusions named the Sierra Norte-Ambargasta Batholith
(SNAB) (Lira et al. 1997; Siegesmund et al. 2010). Mag-
matic activity ceased in the late Cambrian with the
emplacement of the Onca´n porphyritic rhyolite dykes
(Rapela et al. 1991; 494 ± 11 Ma). The SNAB encloses
large roof-pendants of a locally contact overprinted meta-
morphic complex (Table 1). The ages of these metamor-
phic rocks have been assigned to the late Precambrian
(Siegesmund et al. 2010 and references therein).
The Sierras de Co´rdoba constitute a unit of igneous and
low- to high-grade metamorphic para and orthogneisses,
marble, amphibolites and ultramafic rocks, which under-
went local partial melting processes that lead to migmati-
tization. Peraluminous and metaluminous granitoids of
466 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
different ages intrude this basement (Rapela et al. 1998;
Sims et al. 1998). The polymetamorphic complexes are
organized in lithological and structural domains (Fig. 2):
Sierra Chica, Sierra Grande and Sierra de Comechingones
separated by ductile shear zones and mafic and ultramafic
rocks (Siegesmund et al. 2010 and references therein).
These domains are characterized by Ediacarian sedimen-
tation and late Ediacaran to Cambrian deformation,
Fig. 1 Schematic map of the
Early Paleozoic sequences of
the Sierras Pampeanas,
Cordillera Oriental and Puna
basement units (modified from
Dalla Salda et al. 1998). Limits
of the Pampean and Famatinian
orogens were taken from Rapela
et al. (2007)
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 467
123
468 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
magmatism and metamorphism with a more restricted
Ordovician magmatic event (Rapela et al. 1998; Siegesmund
et al. 2010) and voluminous intrusions of Devonian gran-
ites. A NNW trending belt of granulite-facies metamorphic
rocks and related S-Type granitoids (Fig. 2) can be split
into the San Carlos Massif in the NW and to the SE into the
Sierra de Comechingones (Guereschi and Martino 2008
and references therein). Mafic and ultramafic rocks that
were in part interpreted as ophiolites were separated into an
eastern belt called the Sierra Chica and a western belt
known as the Sierra Grande (Mutti 1987; Escayola et al.
1996).
The Sierra Chica (Fig. 2) has been subdivided into
a series of metamorphic complexes. Most southward, the
Las Pen˜as metamorphic complex (Bonalumi et al. 2001)
comprises medium- to high-grade metamorphic rocks
(Table 1). In the central part, gneisses, homogenous and
heterogeneous migmatites, marbles and amphibolites con-
stitute the Sierra Chica Metamorphic Complex (Martino
et al. 1995). In the north, partly migmatized gneisses with
rare marble and amphibolite are present together with
hornblende and biotite-bearing tonalite, granodiorite, bio-
tite-bearing granite, granitic orthogneisses and banded
paragneisses (Rapela et al. 1998).
The Sierra Grande is dominated by medium- to coarse-
grained granitoid, K-feldspar-cordierite migmatites, ana-
tectic granitoids and interlayered biotite gneisses and
amphibolites of the San Carlos Massif (SCM; Bonalumi
et al. 2001). This massif is limited to the east by quartz-rich
micaceous gneisses and biotite-bearing quartz-feldspar
gneisses that host marbles, amphibolites, and pegmatites.
Toward the west, the SCM grades into gneisses and stromatic
migmatites, which were overthrusted along the moderately
inclined, NNW trending reverse Los Tu´neles shear belt
(Martino 2003) onto phyllites (Mermela group). The defor-
mation in the Los Tu´neles shear belt is constrained between
the late Cambrian and the early Ordovician (Steenken et al.
2010). Guereschi and Martino (2008) proposed that a partial
melting process related to the metamorphism (&700C,
5.5–6.5 Kb) results from the exhumation after a compres-
sional event. (Fig. 3). The Las Palmas gneiss located
southwest of the SCM is a strongly folded high-grade banded
gneiss (Gordillo 1984), which grades into cordierite-bearing
diatexite, i.e. the Piedras Rosadas.
In the Sierra de Comechingones, three complexes
(Otamendi et al. 1998, 2000; Sims et al. 1998) are distin-
guished: north of the Devonian Cerro Aspero batholith
(Fig. 2) the Sierra de Comechingones Metamorphic
Complex (SCMC) and to the south, the Monte Guazu´
and the Achiras complexes (Table 1). The SCMC consists
of a medium- to high-grade metasedimentary sequence,
peraluminous leucogranites, marble/calc-silicate, gabbros,
amphibolite with MORB-like affinities and mafic–ultra-
mafic rocks (Otamendi et al. 2004 and references therein).
Martino et al. (1995) separated the SCMC into the cordi-
erite-bearing diatexites and stromatic migmatites of the
Yacanto group. The locally interlayered San Miguel group
is composed of mafic and ultramafic rocks, garnet-bearing
gneisses and marbles and the Santa Rosa cordierite-garnet
granulite. The mafic rocks also appear widespread as small
intrusive dikes and as pillows in the migmatites (Otamendi
et al. 2004). The Monte Guazu´ Complex is distinguished
by having a probably Ordovician (Gromet et al. 2001;
Drobe et al. 2010 this volume) suite of intermediate calc-
alkaline igneous rocks interlayered with medium- to
high-grade metasedimentary rocks (Fagiano et al. 2008;
Otamendi et al. 2000). The Achiras Complex is a monot-
onous sequence comprising discontinuous belts of grey-
wacke-derived amphibolite-facies gneisses and schists that
are interlayered with peraluminous leucogranites. The
complex is intruded by Devonian peraluminous granites,
like the Achiras granite (384 ± 6 Ma, U–Pb zircon, Stuart-
Smith et al. 1999). Fagiano et al. (2008) proposed an
Ordovician age for the metamorphism of the Achiras
Complex (Table 1). The Achiras Metamorphic Complex
was correlated with the Conlara Metamorphic Complex
(Sims et al. 1998).
The aforementioned metamorphic complexes affected
the moderately east-dipping, N–S trending early Cambrian
to Silurian Guacha Corral shear belt (Martino 2003;
Steenken et al. 2010; Fig. 2), which juxtaposed the base-
ment of the Sierra de Comechingones on top of the eastern
slope of the Sierra de San Luis, i.e. the Conlara Meta-
morphic Complex.
Sierra de San Luis
The Sierra de San Luis (Figs. 1, 2) records an Ediacaran
to Devonian metamorphic and magmatic evolution and
comprises three NNE—SSW striking basement domains of
amphibolite- to granulite-facies complexes, the Nogolı´,
Pringles and Conlara metamorphic complexes (Sims et al.
1997). The domains are generally (Fig. 2) separated by an
assemblage of metaquartz arenites and phyllites: the San
Luis Formation (Prozzi and Ramos 1988) and are intruded
by Ordovician and Devonian granitoids (Sims et al. 1997,
1998; Lo´pez de Luchi et al. 2007). The metamorphic
events and mineral parageneses are summarized in Table 1.
The Conlara Metamorphic Complex (CMC) is the
easternmost of these complexes. The western margin of the
Fig. 2 Simplified geological map of the Sierras de Co´rdoba, the
Sierra Norte, the Sierra de Chepes and the Sierra de San Luis
(modified from Martino 2003; Steenken et al. 2006 and Siegesmund
et al. 2010). Detrital zircon age spectra and TDM ages for felsic
igneous and metaclastic rocks are included
b
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 469
123
Table 1 Mineral paragenesis, P–T constraints and ages of the Pampean and Famatinian metamorphic events
Lithology PT conditions Age References
Sierras de Co´rdoba
Sierra Norte
Roof pendants in SNAB M1 Low-grade slates and schists;
medium-grade amphibolites
and marbles; high-grade
gneisses and migmatites
584– 560 Ma Llambı´as et al. (2003)
Sierra Chica
Las Pen˜as MC M2? Orthogneisses; metabasic rocks,
amphibolites, impure marbles,
Grt ? Cdr ? Kfs migmatites
Bonalumi et al. (2001)
Sierra Chica MC M2? Sill ? Cdr ? Grt migmatites 6–6.5 Kbar
700–750C
Martino et al. (1995)
Amphibolites, marbles,Grt ? Bt
gneisses
Gordillo (1984)
La Calera Group M2 Metabasic rocks 9 Kbar 810C 522 ± 8 Ma mon Rapela et al. (1998)
Crd ? Grt Diatexites 6 Kbar 820C Baldo et al. (1996)
San Roque MC M2? Ms ? Sill gneisses, Bt gneisses Rapela et al. (1998)
Ti-rich amphibolites Baldo et al. (1996)
El Diquecito Group Tonalitic orthogneisses Rapela et al. (1998)
Sill ? Grt ? Kfs gneisses Baldo et al. (1996)
Marbles; diopside-rich
amphibolites
M2 Crd migmatites 6 Kbar 820C 522 ± 8 Ma mon
Ascochinga Complex M2? Banded paragneisses Rapela et al. (1998)
Sierra Grande
San Carlos Massif M2 Crd ? Sill migmatites 5.5–6.5Kbar 700C Ca.530 Ma Peak at
500–560 Ma
Guereschi and Martino
(2008)
Bt gneisses Escayola et al. (2007)
Las Palmas M1 Grt ? Sill ? (Kfs ? Bt) banded
gneisses
543 ± 4 Ma Gordillo (1984); Siegesmund
et al. (2010)
Pichanas Complex M2 Grt gneiss Low P high T 531 ± 10 Ma Sims et al. (1998)
M1 561 ± 10 Ma
Los Tu´neles Phyllite 250–280C Detrital peak at
600 Ma
Escayola et al. (2007)
North Achala Crd gneisses 4.5 Kbar 685C Baldo et al. (1996)
Quilpo Fm M2 Crd ? Sill ? Grt gneiss 529 ± 10 Ma Sims et al. (1998)
M1 Bt-Grt gneiss 581 ± 16 Ma
Sierras de Co´rdoba
Sierra de Comechingones
Sierra de Comechingones MC
Can˜ada del Sauce M1 Bt-Grt-Crd-Kfs diatexite 5.5–6 Kbar
725–780C
577 ± 11 Ma Siegesmund et al. (2010)
Guereschi and Martino
(2008)
Tala Cruz M1 Bt ? Sill ? Grt ? Kfs
Stromatite
8.5–9 Kbar
810–840C
553 ± 3 Ma Guereschi and Martino
(2008)
Sierra de Comechingones
MC
Gneiss, diatexites
Amphibolites and peridotites Otamendi et al. (2004)
Santa Rosa Massif M2 Crd migmatites 7.5 Kbar 850–900C 536 ± 11 Ma Otamendi et al. (2006)
511 ± 6 Ma Siegesmund et al. (2010)
Monte Guazu´ Complex M2 Kfs ? Sill ? Grt stromatitic
migmatite
7 Kbar 750C Fagiano et al. (2008)
M1 Pl ? Qz ? Bt ± Grt paragneiss
470 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
Table 1 continued
Lithology PT conditions Age References
Achiras MC M1 Grt ? Bt ? Pl ? Qtz schist \5 Kbar 420–530C Fagiano et al. (2008)
M2 5–8 Kbar 760C Otamendi et al. (2004)
Sierra de San Luis
Pringles MC M1/
M2
Pl-Kfs-Grt-Bt-Sill ± Crd
granulite
5.7–6.4 Kbar
740–790C
498 ± 10 Ma Steenken et al. (2006)
Chl ? Bt ? Ms ? Qtz ? Pl ?
Kfs amphibolite
Micaschists, migmatites and
amphibolites
Hauzenberger et al. (2001)
Nogolı´ MC M2? Bt ? Sill ? Pl migmatite;
micaschists, metaquartzites,
migmatites and amphibolites;
metabasalts
478 ± 4 Ma Steenken et al. (2006)
Bt-Pl-Grt gneiss 5–8 Kbar 660–791C Gonza´lez et al. (2009
San Luis Fm M1 Ill ? Chl ? Bt ? Qtz ± Ab ±
Grt phyllite
250–350C Post 530- pre ca
480 Ma
Drobe et al. (2009)
Conlara MC M2 Bt ? Qtz ? Pl ± Grt banded
schist
35 Kbar 3600C 564 ± 21 Ma Siegesmund et al. (2010)
Metagreywackes, metapelites,
turmaline schist
Detrital
ages \ 560 Ma
Sierra de Chepes
Roof pendants in granitoids M2 Low-medium grade metapelites
Bt to Crd zones 3 Kbar 400–700C 478 ± 9 Ma Pankhurst et al. (1998)
Migmatites (And-Kfs zone)
Sierra de Velazco
Phyllites (Bt zone) Toselli (1990), Rapela et al.
(2001),Toselli et al. (2005)
Micaschists, metaquarzites (And
zone)
Crd migmatites (Sill-Kfs zone)
Antinaco orthogneiss 5–7 Kbar 600C 471 ± 3 Ma
Sierra de Ancasti
West
Ancasti Fm. Metasediments Willner (1983)
Portezuelo Fm. Crd ? Bt ? Sill ? Kfs ± Grt
Gneisses
M2 Qtz ? Pl ? Kfs ? Bt ? Grt
Migmatites
ca.472 Ma
Cent.
Ancasti Fm. Folded banded schists
M1 Bt ? Pl ± Grt ± Ms schists Low P 524 ± 28 Knu¨ver (1983); Willner
(1983)
East
Jumeal Mb of Sierra Brava C. Paragneisses, migmatites Acen˜olaza and Toselli (1977)
La Calera Mb of Sierra Brava
C.
Marbles, schists, and
amphibolites
Sierra de Quilmes
SW
Met-equiv. Amphibolite-facies rocks ca.470 Ma Bu¨ttner et al. (2005)
Puncoviscana Fm. Migmatites ca.6 kbar 800C
NE Very low-grade clastic
metasedimentary rocks
M1 and M2 refer to the stages of metamorphism as described in the cited articles. These labels are not used in the text
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 471
123
CMC is affected by the Devonian Rı´o Guzma´n shear zone,
whereas its eastern margin toward the Sierra de Come-
chingones (Sims et al. 1997) is controlled by the Guacha
Corral shear zone. The metamorphic series of the CMC
comprises NNE trending metagreywackes and scarce
metapelites and metaigneous components, which encom-
pass basic sills and granitic rocks. These belong to two
distinct groups: an earlier one represented by orthogneis-
ses, locally migmatites, mainly tonalitic to granodioritic
and scarce amphibolites and a later granitic one, which
comprises late Cambrian to early Ordovician monzogranite
to tonalitic plutons (i.e. La Tapera, El Pen˜o´n, El Salado)
and a group of large granitic pegmatites.
The Nogoli Metamorphic Complex (NMC) is composed
of paragneisses, mica schists, metaquartzites, and migma-
tites, with minor amphibolite and small lenses of two micas
and garnet leucogranites. Gonza´lez et al. (2009 and refer-
ences therein) proposed that part of the amphibolites are
meta-komatiites, and high-Fe tholeiite metabasalts, which
are interlayered with marbles and banded iron formation.
W to NW trending remnants were considered as pre-
Famatinian (Pampean?), whereas NNE to NE trending
penetrative deformation were related to the Famatinian
deformation (Gonza´lez et al. 2004). Prograde regional
metamorphism accompanies deformational phases, from at
least middle greenschist to high amphibolite facies.
The Pringles Metamorphic Complex (PMC) consists of
paragneisses, mica schists, migmatites, and amphibolites.
Discontinuous lenses of mafic (mainly norites) to ultramafic
units occur along a narrow NNE–SSW central belt concor-
dant with the NNE-trending S2 foliation. Granulite-facies
metamorphism, which would result from the emplacement
of (ultra-) mafic intrusions, occurred during the beginning of
the Famatinian cycle (Fig. 3; Hauzenberger et al. 2001;
Steenken et al. 2005, 2006; Delpino et al. 2007). Granulite-
facies assemblages grade into amphibolite and greenschist
facies assemblages (Hauzenberger et al. 2001; Delpino et al.
2007).
The NNE trending low-grade phyllites and meta-
quartz-arenites of the San Luis Formation appears in two
belts (Fig. 2). NNE trending large-scale tight folds with a
moderate plunge is the main deformation style in the San
Luis Formation, corresponding to the Famatinian event
recorded in the PMC (Steenken et al. 2006, 2008). Isocli-
nally folded quartz layers within the phyllites (Fig. 2)
suggest a preceding deformation phase. The transpressional
Rı´o Guzma´n shear zone that accommodated the ‘‘east-side-
up’’ displacement of the CMC is developed along the
eastern belt of this formation (Steenken et al. 2008).
Sierra de Chepes
The Sierras de Chepes, Malanza´n, and Los Llanos (Fig. 2)
are composed of early Ordovician metaluminous, calcal-
kaline granitoids, and restricted peraluminous S-type
monzogranites. Small bodies of gabbro diorite or quartz
diorite frequently mingled with the surrounding granodi-
orites. The most important granitoid unit is the 490 ±
5 Ma (U/Pb zircon age) Chepes Granodiorite (Pankhurst
et al. 1998). The metasedimentary rocks in the Sierras de
Chepes occur as discontinuous roof pendants of the host
(Pankhurst et al. 1998). These greenschist to amphibolite
grade rocks are largely metapelites with intercalations of
metarenites. A first metamorphism is represented by fine-
grained inclusions of biotite, magnetite, quartz, and musco-
vite preserved in cordierite porphyroblasts. The second, but
low-pressure metamorphism, which was considered as coe-
val with the granitoid emplacement (Pankhurst et al. 1998),
grades from phyllite to an anatectic zone (Pankhurst et al.
1998). The metamorphic events and mineral parageneses are
summarized in Table 1.
Main geological features of other basement blocks
in the Eastern Sierras Pampeanas
The Sierra de Quilmes metamorphic complex (Fig. 1)
consists of upper to mid-crustal, mainly siliciclastic meta-
sediments and shows a continuous, northeast to southwest
transition from very low- and low-grade metamorphic
clastic sediments into amphibolite facies and migmatitic
Fig. 3 P–T path for high-grade metamorphic rocks of the Sierra de
Comechingones and the Pringles Metamorphic Complex. a P–T path
for the Pringles Metamorphic Complex taken from Delpino et al.
(2007) and b the P–T path for the Sierra de Comechingones after
Guereschi and Martino (2008). Note that the trajectories are different
for the Sierra de Comechingones and the Pringles Metamorphic
Complex. In the former, higher grade reactions are crossed before
decompression; whereas in the latter, these reactions pre-dated an
isothermal compression path. Compilation of reactions by Otamendi
et al. (2004) according to VM94 (Vielzeuf and Montel 1994) and
SKC99 (Spear et al. 1999). Mineral abbreviations after Kretz (1983)
472 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
rocks (Table 1). The protoliths were mainly turbiditic
sediments of the Puncoviscana Formation (Toselli 1990;
Toselli and Rossi de Toselli 1990). Bu¨ttner et al. (2005)
calculated an Ordovician age for the metamorphic peak.
The Sierra de Velasco (Fig. 1) is dominated by grani-
toids. Low-grade metamorphic rocks (Table 1) are only
present as small outcrops along the eastern flank. These
phyllites and mica schists have been correlated with the
lower Ordovician metasedimentary La Ce´bila Formation
(Verdecchia et al. 2007; Grosse et al. 2008), which sepa-
rates the Sierra de Velasco from the Sierra de Ambato
(Fig. 1).
The Sierra de Ancasti (Fig. 1) comprises three meta-
morphic domains. The eastern flank, the Sierra Brava
Complex is composed of paragneisses and migmatites
(Acen˜olaza and Toselli 1981) as well as marbles, schists,
and amphibolites. The central sector is mostly formed by
folded NNW-SSE trending banded schist of the Ancasti
Formation (Acen˜olaza and Toselli 1981; Willner 1983),
which records a low-pressure Pampean metamorphism that
was overprinted by a syn-deformational medium-grade
event (Willner 1983; Knu¨ver 1983; Gaido 2003). In the
western flank, metasediments of the Ancasti Formation
prograde into gneiss and migmatites of the El Portezuelo
Formation (Willner 1983). Ordovician granites and tour-
maline- and beryl-bearing pegmatites are emplaced in the
Sierra Brava Complex and the Ancasti Formation. The
metamorphic events and mineral parageneses are summa-
rized in Table 1.
Time constraints for the Pampean metamorphism
Time constraints for the sedimentation of the clastic units
that later constituted the Pampean metamorphic basement
of the Eastern Sierras Pampeanas are provided by detrital
zircon ages of the different units of the Sierras de Co´rdoba,
the CMC (Fig. 2) and the Ancasti Formation. In the Sierras
de Co´rdoba, younger detrital zircons are around 550 Ma as
well as in the Conlara Metamorphic Complex (Steenken
et al. 2008; Siegesmund et al. 2010). In the Sierra de
Ancasti, the youngest detrital peak is ca. 570 Ma (Rapela
et al. 2007).
In the Sierra Norte, age constraints for the metamorphic
evolution predating the emplacement of the SNAB grani-
toids are provided by two ages. First, the 584 Ma age of an
ignimbritic rhyolite (Llambı´as et al. 2003) which is inter-
layered with a metaclastic gneiss, and secondly, the U/Pb
age of 533 ± 12 Ma for the San Miguel orthogneiss
located along the eastern flank of the Sierra de Sumampa
(Siegesmund et al. 2010).
Rapela et al. (1998, 2002) and Otamendi et al. (2006)
related the main Pampean migmatization event, cordierite
formation and metamorphic peak at *530 Ma in the
Sierra Grande and in the Sierra de Comechingones to a
second phase of metamorphism. In the Sierra Grande, the
U/Pb zircon age of 543 ± 3.6 Ma for the high-grade non-
migmatitic Las Palmas gneiss (Fig. 2) (Siegesmund et al.
2010) suggests an earlier onset of metamorphism than
widespread anatexis at *530 Ma. In the Sierra de Come-
chingones Metamorphic Complex, the Tala Cruz migma-
tites yielded a concordant SHRIMP U/Pb zircon age of
553.5 ± 3.2 Ma (Siegesmund et al. 2010), whereas the
Can˜ada del Sauce diatexite (Guereschi and Martino 2008)
yielded an older metamorphic event of 577 ± 11 Ma
(Siegesmund et al. 2010). Therefore, portions of the
basement of the Sierra de Comechingones might be older
than Late Ediacaran and the ubiquitous metamorphic
equivalents of the Puncoviscana Formation. The Santa
Rosa Grt-Crd granulite, i.e. the restite of the melting event
related with the second phase of metamorphism, yielded a
U/Pb zircon age of 536 ± 11 Ma (Siegesmund et al. 2010).
Constraints on the younger limit of the metamorphism
are provided by PbSL titanite ages obtained from calc-
silicate intercalations in the San Carlos Massif, which
yielded an age of 505.7 ± 7.3 Ma (Siegesmund et al.
2010). K/Ar and Ar/Ar muscovite ages starting at 502 Ma
were reported by Krol and Simpson (1999) and Steenken
et al. (2010). These ages mark the end of the Pampean
metamorphism and may suggest a relatively fast exhuma-
tion of the Pampean orogen at *500 Ma. This event cor-
relates with the first activation of the Guacha Corral and
Los Tu´neles shear zones (Steenken et al. 2010), the initi-
ation of renewed compression along the Gondwana margin
(Steenken et al. 2006 and references therein) and with the
Iru´yica deformation phase (Astini et al. 2008), an early
phase of the Famatinian orogeny.
Evidence that the Pampean orogeny started in the
Ediacaran is also provided by the Pb/Pb garnet age of
564 ± 21 Ma (Siegesmund et al. 2010) for the banded
schist of CMC. In the Sierra de Ancasti, detrital zircons of
the Ancasti Formation (Rapela et al. 2007) indicate that the
sedimentation should be youngest than 600–570 Ma. The
main tectonothermal event affecting these rocks is assigned
to the Pampean orogeny based on the Rb–Sr mineral iso-
chron of 524 ± 28 Ma (Knu¨ver 1983). In Table 1, ages
and P–T-t constraints of the Pampean metamorphic events
are summarized.
Time constraints for the Famatinian metamorphism
Ordovician Famatinian metamorphism is mostly related to
the closure of ensialic back-arc or inter-arc basins devel-
oped east (in the ESP) or inside the main Famatina mag-
matic arc in the Sierra de Famatina (Balhburg 1991;
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 473
123
Steenken et al. 2006; Dahlquist et al. 2008; Collo et al.
2009; Drobe et al. 2010 this volume). In the latter (Fig. 1),
low-grade metamorphism and deformation are bracketed
between 457 ± 9 and 463 ± 14 Ma (Collo et al. 2008).
The youngest detrital zircon ages exhibit a major peak at
486 ± 5 Ma and possibly a younger one at 463 ± 7 Ma,
which suggests a derivation from the active Famatinian arc
(Dahlquist et al. 2008).
SHRIMP and PbSL analysis indicate a concordant U/Pb
age at 498 ± 10 Ma for granulite-facies metamorphism of
the Pringles Metamorphic Complex (Steenken et al. 2006,
2008). Pb/Pb garnet ages indicate that the Pb isotope equil-
ibration took place during the middle to late Ordovician
(452 ± 19 Ma), defining the youngest age of the metamor-
phism. Post-dating the onset of high-grade metamorphism,
the Pringles Metamorphic Complex was intruded by ca.
490 Ma granitoids (Steenken et al. 2006). At around
478–468 Ma, granodioritic to tonalitic rocks intrude the
low-grade San Luis Formation post-dating the onset of the
first metamorphic overprint (Steenken et al. 2006).
A pre-Famatinian deformational and metamorphic his-
tory for the Nogolı´ Metamorphic Complex was proposed
by von Gosen and Prozzi (1998), Sato et al. (2003) and
Gonza´lez et al. (2004, 2009). The banded iron formation
and mafic to ultramafic meta-volcanic rocks should be of
Mesoproterozoic age (Gonza´lez et al. 2009). Conventional
U–Pb monazite and zircon, chemical Th–U–Pb total
monazite, and Ar–Ar hornblende plateau ages from par-
agneisses, orthogneisses and amphibolites range between
475 and 457 Ma and constrain the timing of regional high-
grade metamorphism to the early to mid-Ordovician
(Gonza´lez et al. 2004; Steenken et al. 2006). Steenken et al.
(2006) reported a Th/Pb SHRIMP monazite age of
478 ± 4 Ma for a migmatite from the northern part of the
complex, and a Pb/Pb age of 460 ± 12 Ma for peralum-
niuos S-type garnet leucomonzogranite from the central
part of the complex. Detrital ages of the NMC define a
maximum around 530 Ma (Steenken et al. 2006; Drobe
et al. 2009).
In the Sierra de Chepes, an early to middle Cambrian
metamorphism was proposed by Pankhurst et al. (1998)
based on an Rb–Sr errorchron of 513 ± 31 Ma. Banded
schist from the Sierras de Chepes yielded detrital ages
between 540 and 511 Ma with an average of 525 Ma
(Drobe et al. 2010 this volume).
Bu¨ttner et al. (2005) proposed that for the Sierra de
Quilmes metamorphic complex the metamorphic peak in
migmatites and calc-silicate rocks is at or slightly prior
to *470 Ma.
In Table 1, a summary of the P–T constraints and ages of
the Famatinan metamorphism is presented. Therefore, it can
be concluded that the Famatinian orogen consists of two
stages of compression, one related to the onset of subduction
at around 500 Ma and another stage at ca. 470 Ma that is
related to the cessation of the Famatinian magmatism.
Magmatism in the Eastern Sierras Pampeanas
Rapela et al. (1990) separated granitoids of the Sierras
Pampenas into G1, G2 and G3 that roughly correspond in
time to the Pampean, Famatinian, and Achalian orogenies.
Rapela et al. (1998), Quenardelle and Ramos (1999),
Pankhurst et al. (2000) and Rapela (2000) considered that
the Pampean magmatism is arc-related with minor post-
collisional peraluminous intrusions. Famatinian magma-
tism is arc-related and I-type in the west and grades into
S-type granitoids toward the continent. Devonian magma-
tism would be either arc-related with a Devonian subduc-
tion along the western margin of the Precordillera terrain or
the result of post-Ordovician uplift.
Ediacaran to Cambrian Granitoids
Calc-alkaline magmatic rocks of Ediacaran and Cambrian
age form the batholith of Sierra Norte and extend discon-
tinuously southward along the Sierra Chica (Rapela et al.
1998). These rocks consist of metaluminous to weakly
peraluminous granitoids and associated volcanic rocks
(Lira et al. 1997) and exhibit intrusive contacts with the
metasedimentary host. Granodiorites and monzogranites
are the dominant rocks with late-stage rhyolites, and
miarolitic monzogranites (Lira et al. 1997). Aplites, por-
phyries, and pegmatites intrude all the sequences (Rapela
et al. 1991). The geochemistry suggests that these grani-
toids are arc-related (Lira et al. 1997) and would provide a
record of subduction and convergent margin tectonics
along the western margin of Gondwana in the late Neo-
proterozoic. Geochronological studies from the Sierra
Norte granitoids (Schwartz et al. 2008) indicate a period
of emplacement bracketed between 550 and -530 Ma.
A SHRIMP U–Pb zircon age of Ma 515 ± 4 was obtained
for the Ojo de Agua granite in northeastern Sierra Norte
(Stuart-Smith et al. 1999).
Cambrian granitoids (the G1b suite of Rapela et al.
1998) located in the Sierra Grande and Sierra de Come-
chingones are peraluminous anatectic melts of the meta-
sedimentary country rocks (Rapela et al. 1998). Ages of
these groups of plutons are bracketed between 523 ± 2 for
El Pilo´n (Rapela et al. 1998, 2001) and 529 ± 3.4 for the
Juan XXIII pluton (Escayola et al. 2007; Fig. 2).
In the Sierra de San Luis, Cambrian granitoids would
correspond to orthogneisses interlayered with the meta-
clastic units of the Cambrian CMC. In the NMC, an age of
ca. 530 Ma (Vujovich and Ostera 2003) was calculated for
a granodiorite located in the northern part of the complex.
474 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
Ordovician Granitoids
Pankhurst et al. (2000) have identified three distinct gran-
ite-types: a dominant I-type, small-scale S-type, and tona-
lite-trondhjemite-granodiorite, which are contemporaneous
within the 484–463-Ma interval (Dahlquist et al. 2008 and
references therein). I-type magmatism is represented by
tonalites, granodiorites, minor monzogranites, and gabbros
that can be traced from the NW in Catamarca and La Rioja
down to the Sierras de Valle Fe´rtil-La Huerta in the San
Juan province and the Sierra de San Luis. The S-type
granitoids are developed in Sierra de Velasco, Sierra de
Chepes, and in a sector of the Sierra de San Luis (Steenken
et al. 2006, 2008). The TTG group (TTG, i.e. El Hongo,
Calmayo, La Fronda, Guiraldes, La Playa and Paso del
Carmen tonalite to granodiorite plutons) is emplaced in the
Sierra Grande except for the Calmayo group (500–480 Ma,
U–Pb zircon, Rapela et al. 1998), which intrudes the Sierra
Chica Complex.
Lo´pez de Luchi et al. (2007) considered that the Ordo-
vician granitoids (ca.500–470 Ma) of the Sierra de San
Luis (Fig. 4) are synkinematic with compressive defor-
mation related to the early stages of Famatinian conver-
gence. These authors proposed a separation of the
granitoids of the Sierra de San Luis into an Ordovician
tonalite suite (OTS; metaluminous to mildly peraluminous
calcic tonalite-granodiorites) and an Ordovician granodio-
rite–granite suite (OGGS; peraluminous calcic to calc-
alkaline granodiorite-monzogranites). In the Conlara
Metamorphic Complex, the OGGS (Fig. 4a) comprises the
early Ordovician monzogranite to tonalitic plutons (i.e. La
Tapera, El Pen˜o´n, El Salado) and the group of large
granitic pegmatites, which show comparable deformation
microstructures.
Lower Ordovician metaluminous calc-alkaline grani-
toids which constitute the principal lithologies of the
Sierras de Chepes, Malanza´n and Los Llanos (Fig. 2) fre-
quently exhibit mingling relationships with gabbro diorite
or quartz diorite. The most important granitoid unit is the
490 ± 5 Ma (U/Pb zircon age) Chepes Granodiorite
(Pankhurst et al. 1998).
Ordovician metagranitoids of the Sierra de Velasco
(Toselli et al. 2005, Ba´ez et al. 2005) consist of strongly
peraluminous porphyritic two-mica-, garnet-, sillimanite-
and kyanite-bearing meta-monzogranites (Rossi et al.
2005). Subordinate varieties include biotite–cordierite
meta-monzogranites and biotite meta-granodiorites and
meta-tonalites. In the southern part of the Sierra, the main
lithologies are metaluminous to weakly peraluminous
biotite-hornblende meta-granodiorites and meta-tonalites
(Bellos 2005).
In the Sierra de Ancasti, Ordovician granitoid magma-
tism is represented by calc-alkaline and metaluminous
plutons and minor garnet-bearing two-mica granite stocks
(Reissinger 1983; Rapela et al. 2005). In the Sierra de
Quilmes, Famatinian magmatism is represented by the
composite peraluminous to metaluminous granitoids of the
Cafayate pluton (Bu¨ttner et al. 2005).
Devonian to Lower Carboniferous Granitoids
Paleozoic magmatism in the Sierras Pampeanas ended
with the intrusion of a suite of middle Devonian to
Lower Carboniferous batholiths (Lo´pez de Luchi 1996;
Fig. 4 Diagnostic features of the Ordovician and Devonian grani-
toids of the Sierra de San Luis. a Tectonic classification R1–R2. More
evolved granites cluster in the syncollisional field. Samples of the
Ordovician Tonalite Suite are located along the limit between mantle
fractionates and pre-plate collision fields, which would suggest mafic
sources. Rocks from the Ordovician granodiorite-granite suite trend
from the pre-plate collision to syncollisional fields, which correlate
with their dominant crustal sources. Devonian hybrid granitoids
extend from the post-collisional uplift to late-orogenic fields indicat-
ing enriched mafic sources to the syn-collisional field, which
represent either crustal derived or fractionated melts. b Chondrite-
normalized REE patterns (Boynton 1984) for rocks with SiO2 \ 66%.
Note that the Devonian intermediate rocks show higher (Gd/Yb)N,
which would suggest their deeper source and an enrichment in light
rare-earth elements
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 475
123
Stuart-Smith et al. 1999; Pinotti et al. 2002; Siegesmund
et al. 2004). They were considered either as post-Fama-
tinian or post-orogenic (Rapela et al. 1998) or as the
Achalian granite group. In the Sierra de Co´rdoba, the
Devonian Achala Batholith is a peraluminous, alkali-calcic
granitoid with sharp and discordant contacts, which would
represent variable proportions of a juvenile mantle com-
ponent and crustal melts formed by dehydration melting of
biotite-bearing gneisses (Rapela et al. 2008). The Cerro
Aspero batholith in Sierra de Comechingones is made up of
biotite granite and leucogranites (Pinotti et al. 2002, 2006).
In the Sierra de San Luis, voluminous Devonian batholiths
(Las Chacras-Potrerillos, Renca, La Totora, and El Hornito)
are made up of an I-type hybrid monzonite–granite suite
with metaluminous alkali-calcic (393–385 Ma) monzonite-
quartz monzonite–granodiorite ± monzogranite and pera-
luminous alkali-calcic monzogranites (Fig. 4a, b) (Lo´pez de
Luchi et al. 2007). Undeformed granites of Lower Car-
boniferous age (Dahlquist et al. 2008) are located in the
north (Ba´ez et al. 2005) and central (Grosse et al. 2008)
parts of the Sierra de Velasco. They have some features in
common with the Devonian granitoids, i.e. nearly circular
shapes, general lack of pervasive solid-state deformation,
discordant relationships with the host, shallow emplace-
ment, syeno- to monzogranitic compositions, porphyritic
textures and an abundance of pegmatites and aplites. Miller
and So¨llner (2005) proposed that the Devonian to early
Carboniferous magmatism is related to post-orogenic
regional crustal heating, whereas Grosse et al. (2008) pro-
posed that the general age decrease of the Achalian mag-
matism from south to north could have been related to a
progressive delamination of the crust coupled with upper
mantle upwelling from south to north.
Neoproterozoic (ultra-) mafic rocks of the Sierra de
Co´rdoba
The NNW-SSE trending eastern belt is composed of
lherzolite with interlayered websterite and subordinate
harzburgite, abundant pyroxenite and gabbros. Mutti
(1992) described abundant leucocratic plagiogranite dikes.
Escayola et al. (1996) assigned the tectonic setting to an
ensialic back-arc basin, whereas Ramos et al. (2000)
interpreted the belt as ophiolite remnants of a back-arc
zone. Anzil and Martino (2009) considered that the ultra-
mafic sequence would correspond to an obducted lens or
slice of oceanic mantle, probably part of a basal tectonite of
an ophiolitic complex.
The ultramafic–mafic units of the western belt, which
extend along *300 km, are made up of harzburgites that
were metasomatized by intrusive basaltic dikes (Escayola
et al. 2007). Basaltic dikes are made up of plagioclase-
hornblende ± orthopyroxene ± clinopyroxene. Spinel
dunites are close to these dikes. Escayola et al. (1996)
interpreted the western belt as a suture zone and considered
the ultramafic rocks as dismembered ophiolites with
MORB affinities. Escayola et al. (2007) suggested a
suprasubduction-zone ophiolitic complex formed at a back-
arc stage. Sm–Nd dating of basalt and gabbro dikes,
pyroxenites, and impregnated peridotites of the western
belt yielded an isochron age of 647 ± 77 Ma. The eNd(647)
value of ?5.2 is consistent with an oceanic or back-arc
origin for the ophiolite sequence (Escayola et al. 2007).
Gabbros with OIB signatures located in the Sierra de
Comechingones, which result from the subduction of a
mid-ocean ridge beneath the paleo-Pacific Gondwana
margin, are related to the high-grade metamorphism of the
Sierras de Co´rdoba (Tibaldi et al. 2008).
Within the CMC, ultramafic rocks have not been
reported yet. However, scarce amphibolites are distributed
in a N–S belt through Sierra del Morro, San Felipe and
Villa de Praga. Some tungsten deposits are genetically
related to them (de Brodtkorb et al. 2005).
Ordovician mafic rocks in the Sierra de San Luis
and Sierra de Chepes
Mafic to ultramafic Ordovician complexes are developed in
the central part of the Sierra de San Luis, whereas gabbros
are recognized as small plutons associated with the calc-
alkaline granitoids of the Sierra de Chepes, Sierra de
Fiambala´ and in the Famatina Complex in the Sierra de
Famatina (Fig. 1). In the Pringles Metamorphic Complex,
506–480 Ma mafic to ultramafic bodies for which back-arc
or marginal basin settings were proposed (Sims et al. 1998;
Hauzenberger et al. 2001; Steenken et al. 2008) are rep-
resented by norites to gabbro-norites with minor ultramafic
rocks. On both sides of the mafic to ultramafic bodies, a
metamorphic gradient from granulite to greenschist facies
is observed (Delpino et al. 2007), and therefore a contact
metamorphic origin for the granulite-facies paragenesis
was suggested (Hauzenberger et al. 2001; Steenken et al.
2005, 2006). Amphibole-bearing gabbros associated with
the calc-alkaline complexes of the Sierra de Chepes, i.e. the
Tama gabbro exhibit mingling relationships with the host
granodiorite (Pankhurst et al. 1998).
Isotopic constraints for the Neoproterozoic-early
Paleozoic geodynamic evolution of the Gondwana
margin
Sm–Nd parameters were calculated at 540 Ma for all the
metamorphic rocks, whereas the igneous rock data were
calculated at the crystallization age (Table 2, Figs. 5, 6; see
also Drobe et al. 2009).
476 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
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Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 477
123
Sm–Nd fingerprints for the metamorphic rocks
Metamorphic rocks of the Sierras Pampeanas were plotted
in the fSm/Nd vs eNd(540) diagram (Fig. 6b). As the majority
of the rocks exhibit fSm/Nd in the interval of sedimentary
derived crustal rocks, i.e. between -0.3 and -0.45, TDM1
ages (Drobe et al. 2009) are inferred to reflect the weighted
average crustal residence time of all the detrital contribu-
tions from the source area. Sm–Nd results for the meta-
morphic basement suggest that the TDM1 age interval of
1.8–1.7 Ga, which is associated with the less radiogenic
eNd(540) values of -6 to -8, can be considered as the mean
Fig. 5 Frequency distribution plots of TDM ages for metaclastic and
igneous felsic rocks of the Eastern Sierras Pampeanas. Comparison
between the data collection indicates that the main period of juvenile
input to the continental crust or alternatively reworking of a younger
unexposed segment of the crust corresponds to the Devonian-Early
Carboniferous. Ordovician felsic rocks with model ages younger than
1.4 Ga correspond to a part of the TTG suite of the Sierras de
Co´rdoba. Data base taken from Rapela et al. (1998), Pankhurst et al.
(1998), Millone et al. (2003), Pinotti et al. (2002), Steenken et al.
(2004, 2006), Otamendi et al. (2006), Grosse et al. (2008), Collo et al.
(2009), Drobe et al. (2009, 2010 this volume) and this work
478 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
average crustal composition for the Eastern Sierras
Pampeanas (Figs. 5, 6b). Younger TDM1 ages and more
radiogenic eNd values in metaclastic rocks could reflect
stages of additional juvenile material, a different crustal
source or a petrogenetic process. Collo et al. (2009) indi-
cated that the Gondwanan isotopic signature for the Mes-
oproterozoic source of the Sierra de Famatina (TDM ages
1.8 and 1.6 Ga) differs from the 1.1–0.8 Ga ‘Laurentian-
like’ Grenville signature.
Detrital zircon age patterns for the Pampean metaclastic
rocks of the Sierras de Co´rdoba, the Conlara Metamorphic
Complex and the Ancasti Formation exhibit prominent
Mesoproterozoic and Brasiliano peaks (Fig. 2), whereas
those for the Ordovician metamorphic rocks independently
of their metamorphic grade show some Pampean and a less
pronounced Grenvillian peak suggesting a limited Gren-
villian input. As the Sm–Nd model ages (Fig. 2) are older
than these peaks, the magmatic–metamorphic events sam-
pled by the zircon cores/rims mainly represent recycled
crustal sources.
Although a change in the source for the protoliths of
the Ordovician and Pampean metaclastic rocks is reflected
Fig. 6 eNd(t) vs. fSm/Nd data showing the Eastern Sierras Pampeanas
metaclastic and igneous rocks. a Mafic–ultramafic rocks. Depleted
mantle (DM) sources plot in both right quadrants depending upon the
nature and degree of light-rare-element enrichment of the source at
the time of extraction of the melts. Values of eNd and fSm/Nd for DM
at 500–600 Ma and as a field (dashed line) for the crustal reservoir
represented by the oldest recorded continental crust of the Eastern
Sierras Pampeanas i.e. TDM ages between 1.8 and 1.7 Ga are shown.
Any mixture between these two reservoirs should lie along a mixing
line. Ordovician mafic–ultramafic complex and gabbros are located
close to the crustal field suggesting crustal component incorporation.
b Metaclastic rocks. Note that most of the metaclastic rocks are
restricted to crustal values of fSm/Nd and that the eNd(t) is less
radiogenic for the Ordovician metaclastic rocks, which suggest more
recycling. c Felsic igneous rocks. Pampean rocks older than 540 Ma
separate into two groups. The group with eNd(t) values [ -5
corresponds to the rocks of the Sierra Chica de Co´rdoba in which
mafic microgranular enclaves are found (and show TDM \ 1.6 Ga).
Rocks with eNd(t) values \ -5 correspond to granitoids for which the
metaclastic host is less radiogenic (both sharing TDM ages
ca.1.7–1.8 Ga). A trend from more radiogenic eNd(t) values with
time is observed, and it is accompanied by values of fSm/Nd more
negative than the average continental crust. See text for comments
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 479
123
by the detrital zircon age patterns, the average interval of
crustal residence ages is similar. Metamorphic rocks of
the same grade from different parts of Eastern Sierras
Pampeanas show similar TDM1 ages (Fig. 2) and crustal
fSm/Nd values but less radiogenic eNd(540) values with
decreasing age, which implies an additional recycling
process of the same sources during the Ordovician.
Low- to medium-grade metaclastic rocks of the Sierras
Pampeanas show similar average crustal residence age but
more negative eNd(t) values (Fig. 6b) for the Ordovician
units. The Ordovician Pringles Metamorphic Complex
and the Cambrian Sierra Chica metamorphic rocks show
similar TDM ages but less radiogenic (-6) eNd(540) values
for the PMC. Pampean high-grade metaclastic rocks of
the Sierra Grande de Co´rdoba and Sierra de Comechin-
gones (Fig. 5) show consistently younger TDM ages of
1.6–1.5 Ga, eNd(540) values between -4 and -3 and an
fSm/Nd value above the average -0.4 for the continental
crust. The Ordovician high-grade rocks of the Pringles
Metamorphic Complex exhibits TDM1 ages between 1.7
and 1.6 Ga (Fig. 5) and a mean eNd(540) value of -5.5
(Fig. 6b). Since the zircon age pattern suggests a less
important Grenvillian contribution to the protoliths of the
Pringles Metamorphic Complex, it could be inferred that
the Grenvillian component introduced more radiogenic
compositions.
Younger average crustal residence ages in the Pampean
metaclastic rocks, which can be roughly subdivided into
low to medium- and high-grade rocks, can be ascribed to
the petrogenetic process. Rocks that underwent partial
melting exhibit younger TDM1 ages than those rocks that
lack this process. Although SHRIMP zircon data for the
granulite of the Sierra de Comechingones are scarce,
the persistence of the Mesoproterozoic peaks (Fig. 2) in
the Pampean units (Siegesmund et al. 2010) suggests that
younging of the TDM1 ages results from a petrogenetic
process. Otamendi et al. (2006) proposed that the granulites
were formed by a short-lived event of local thermal input,
which enhanced the possibility that melting was rapid
enough to trigger isotopic disequilibrium. Therefore, the
Sm–Nd data for the high-grade Pampean metaclastic rocks
of Co´rdoba do not identify different sources located east or
west of the Sierra de Co´rdoba as previously proposed by
Escayola et al. (2007).
To summarize, increasing metamorphic grade in rocks
with similar sources and ages like in the Sierras de Co´rdoba
is associated with a younging of the TDM ages and more
positive eNd(540) values. In metaclastic rocks of different
metamorphic ages, the Grenville source introduces a rela-
tively more positive epsilon. The change of source between
the Pampean and the Famatinian metaclastic rocks is
related to a higher degree of recycling as evidenced by the
less radiogenic epsilon.
Sm–Nd fingerprints for the magmatic rocks
Sources and evolution of neodymium isotopic ratios of the
magmatic rocks are analyzed in the eNd versus fSm/Nd plot
(Fig. 6a, c) for time corrected epsilon values (Shirey and
Hanson 1986).
Mafic–ultramafic complexes
Our own database for the mafic rocks (Table 2) was
combined with data from Pankhurst et al. (1998), Rapela
et al. (1998), Sato et al. (2001), de Brodtkorb et al. (2005)
and Escayola et al. (2007). Sm–Nd results for the mafic–
ultramafic rocks are heterogeneous, which is evident from
the wide range in Sm–Nd isotopic compositions (Table 2),
with eNd(540) values ranging from -6.37 to ?7 and
147Sm/144Nd ratios ranging from 0.09 to 0.3. Consequently,
an ample range of TDM ages were calculated (Table 2).
Rocks of the Eastern belt located in the Sierra Chica de
Co´rdoba (Fig. 6a) can be separated in two groups: mafic–
ultramafic rocks with a depleted mantle signature with
eNd(today) values around 11, eNd(540) values of 6–8.5 and
positive fSm/Nd and another more variable group located in
the northern sector in which amphibolites are characterized
by negative eNd(today) values, positive eNd(540) values, and
negative fSm/Nd. TDM2 ages vary between 570 and 560 Ma.
In the western belt in the Sierra de Comechingones, two
groups can be recognized (Fig. 6a). One group includes
serpentinites and metabasaltic dykes in which eNd(today)
values can be higher or lower than the depleted mantle. The
other group is made up of the gabbros related to the
granulite-facies metamporphism, like Intihuasi, Suya Taco
and Sol de Mayo in which the eNd(today) values are sig-
nificantly lower than that of the contemporary depleted
mantle. If the serpentinites and peridotites are discarded
due to the complex processes involved in their genesis, the
remaining primitive rocks yielded a TDM2 age range of
700–600 Ma, which agrees with the WR Sm–Nd isochron
age calculated for the ophiolite complex of the western belt
(Escayola et al. 2007). It is remarkable that two samples
from the area of Los Tu´neles in the western sector of the
Sierra Grande also yielded TDM2 ages of around 620 Ma.
Uncertainties concerning the crystallization age only
allows for speculation that rocks of the Sierra de Come-
chingones mafic complexes with eNd(540) values higher
than the contemporaneous depleted mantle value, could
indicate that the original liquid was very primitive and
derived from a LREE-depleted source. Alternatively, the
original peridotite protolith could have lost LREE elements
during selective metasomatism.
Older TDM ages and lower eNd(540) values suggest that
the TDM values of these samples reflect enriched signatures
and/or a longer crustal residence time (Arndt and Goldstein
480 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
1987). In the northern part of the Sierra Chica (de Brodt-
korb et al. 2005, Rapela et al. 1998 and Table 2), rocks
considered as amphibolites as well as the gabbros of the
Sierra de Comechingones (Fig. 6a) have eNd(540) values
significantly below that of the contemporary depleted
mantle and were probably derived from the sub-continental
lithospheric mantle. Tibaldi et al. (2008) proposed that the
metasomatic enrichment required for OIB-like magmatism
was caused by low-degree partial melting of progressively
younger and warmer subducted oceanic lithosphere at the
Pampean convergent margin and that subsequent melting
of the overlying enriched mantle wedge produced OIB
magmas.
The norites of the PMC, which plot in the lower left
quadrant of Fig. 6a, could be explained by the mixing of
mantle and crustal components. Their data plot on a mixing
line (Fig. 6a) connecting the DM signature at 500–600 Ma
with the average values for the metaclastic rocks of the
Pringles Metamorphic Complex. Available data on the
amphibolites and komatiitic basalts of the Nogolı´ Meta-
morphic Complex, which show negative eNd and fSm/Nd
values, and consequently variable TDM ages, could also
result from a process of mixing with a crustal component.
Since the crystallization age of these rocks was calculated
from a WR Sm–Nd isochron (Sato et al. 2001), it could
represent a mixing line between crustal and depleted
mantle components.
The less evolved Devonian magmatic rock of the Las
Chacras batholith indicates a younger TDM age (Fig. 5)
coupled with an increase in the eNd value (Fig. 6c).
The Sierras de Co´rdoba mafic–ultramafic complexes
occupy both right quadrants in Fig. 6a, whereas a group of
the Ordovician mafic rocks of the Sierras de San Luis are
located in probable mixing trends of depleted mantle and
continental crust. The magmatic units, which yielded
positive eNd(540) values, indicate juvenile character. Some
samples (Fig. 6a) show high initial eNd(540) values close to
the model depleted mantle curve (Wu et al. 2003). How-
ever, the range of the initial eNd(540) values and the spread
of TDM ages suggest either that the original magma was not
a pure primary melt or that the Sm–Nd system has been
modified by metamorphism or metasomatism. The TDM
ages of rocks with a depleted mantle signature (which
follows the path of the model depleted mantle) may suggest
that formation of oceanic crust in the Sierra Chica could
have been active up to 560 Ma; whereas in the Sierra de
Comechingones, formation of oceanic crust was active
from around 600–700 Ma.
In summary, the analysis of the Sm–Nd results indicates
two types of Pampean-related mafic rocks in which no
interaction with the continental crust in the sense of mixing
or assimilation process is recognized. One group shows a
DM signature and LREE-depleted sources, which could
indicate a stage of ocean crust formation, and another
younger group with a signature of enrichment (cf. Sieges-
mund et al. 2010). On the other hand, in the Ordovician
rocks, the processes of mixing/assimilation of DM signa-
ture melts and continental crust are characteristic. There-
fore, the geodynamic scenario for the Ordovician mafic
rocks could imply thicker continental crust than for the
emplacement of the Pampean mafic rocks or alternatively,
a fast extensional process (extensional collapse) could
prevent modification of the mafic melts in their ascent to
the emplacement level.
Felsic rocks
The overall high abundance of felsic intrusive rocks and
the paucity of intermediate compositions suggest that
crystal fractionation of mafic parental magmas was not
important. The partial melting of crustal sources during
basalt underplating or during crustal delamination is the
dominant process at least during the Pampean and Ordo-
vician cycles. Pre-540 Ma (Figs. 5, 6c) granitoids of the
Sierra de Co´rdoba make up two clusters: one that would be
entirely crustal, since they have TDM ages older than
1.75 Ga and eNd(540) values lower than -5, and another
cluster which corresponds to samples from Sierra Chica de
Co´rdoba in which eNd(540) values are more radiogenic and
TDM ages younger. In the first cluster, melting of a large
amount of old sedimentary protoliths can be suggested;
whereas in the second, since the host is less radiogenic and
older, melting of a variably rejuvenated crust could be
assumed. In this area, tonalites and granodiorites carry
dioritic enclaves suggesting a mixture of a mafic precursor
with metasedimentary sources.
In spite of the episode of mafic magma input to the crust
as shown by the ca. 540 Ma gabbros of the Sierra de
Comechingones, no evidence of this juvenile input is seen
in the post 540 Ma Pampean felsic rocks, which would
represent partial melts derived from the older than 1.75 Ga
basement (Fig. 6c). Therefore, it could be proposed that
mafic magma should have just controlled the melting
process through delamination or underplating.
Although juvenile input is suggested by the mafic rocks
in the Pringles Metamorphic Complex or the gabbros of the
Sierra de Chepes, widespread Famatinian magmatism
with the exception of the minor TTG suites reworked the
old lithospheric sources (Pankhurst et al. 1998). Mostly
evolved granitoids dominate the rock spectrum in the
Famatinian subduction stage. This fact suggests melting of
mostly crustal sources as would be expected in regions of
thick continental crust.
Sources for TTG suites of the Sierra de Co´rdoba are
younger. Data from the Guiraldes and La Fronda thron-
dhjemite together with a leucogranite from the northern
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 481
123
sector of Sierra Chica de Co´rdoba cluster at a TDM age of
ca.1.3 Ga (see Fig. 5), which is accompanied by an
eNd(540) value of -5 and a fSm/Nd value of -0.55 (Fig. 6c).
One throndhjemite of the San Carlos Massif and the La
Playa granodiorite show the youngest TDM age and a
positive or slightly negative value of eNd(470), which sug-
gests a juvenile input.
Lo´pez de Luchi et al. (2007) proposed crustal sources
for the Ordovician tonalite series of the Sierra de San Luis
based on the low Cr and Ni and relatively high K, 87Sr/86Sr
ratios (0.70850–0.71114), and an eNd(470) value (-5.3 to
-6.0), which precludes an origin from variably fraction-
ated mantle melts. The REE pattern of the OTS (Fig. 4b)
reveals subordinate negative Eu anomalies indicating little
plagioclase control during magma evolution, which com-
bined with the low total REE may suggest a source that
underwent previous melting and possibly consumption of
plagioclase.
Field evidence and the age of the mafic–ultramafic rocks
(506–480 Ma) suggest that they crystallized almost at the
same time or slightly before the tonalite-granodiorite OTS
(481–468 Ma) and the 496 Ma of the Paso del Rey S-type
granitoids of the OGGS (Lo´pez de Luchi et al. 2007).
Because mafic melts are denser than hydrous granitoid
melts, large volumes could have intruded into the middle to
lower crust (as indicated by the gravimetric results and
thermal modeling by Kostadinoff et al. 1998; Steenken
et al. 2005). A differentiation/assimilation process in the
lower crust could account for the mixed crustal-mantle
signature of the Ordovician mafic rock as is evident in the
norites of the Virorco complex (Fig. 6a). Mafic magmatism
could thus result from the breaking off of a slab of oceanic
crust during ongoing convergence or from the melting of
the lower crust heated from below by underplating of
basalts or input of heat from delamination of the lower
crust.
The combination of the time span of the mafic
emplacement from 506 to 480 Ma with that of the felsic
igneous rocks from 495 to 470 Ma (Steenken et al. 2006)
argues for a 25 Ma interval of magmatic activity in the
Sierra de San Luis, which is coincident with the time span
assigned to the Famatinian magmatism (Dahlquist et al.
2008 and references therein). Therefore, in the PMC
granulite-facies metamorphism, mafic magma emplace-
ment and I-type and minor S-type magmatism are related to
the active subduction stage of the Famatinan orogeny, a
situation similar to the rest of the Ordovician magmatism
along the margin of Gondwana.
Devonian to early Carboniferous magmatism could have
tapped a juvenile source, which mixed with a crustal end-
member in order to generate the intermediate to acidic
rocks as already proposed by Lo´pez de Luchi et al. (2007).
The Pampean Paleoproterozoic crust or an unexposed
lower crustal segment could represent the aforementioned
crustal end-member. Alternatively, the granitoids may
represent successive episodes of fractionation of enriched
mantle-derived melts. There is almost no overlap between
the Sm–Nd results of this younger group of granitoids
(Figs. 5, 6c) and the rest of the felsic rocks of the Sierras
Pampeanas.
Although some discussion could be addressed concern-
ing the degree of crust-mantle interaction in pre-Devonian
times, crustal reworking is dominant, whereas processes
during the Achalian orogeny led to different geochemical
and isotopic signatures (Lo´pez de Luchi et al. 2007). The
high heat flow associated with the rising mafic magma
during extension is inferred to have partially melted the
crust during peak metamorphism in the Pampean orogeny;
whereas in the Ordovician, the continental arc setting
favored extensive interaction between mantle derived and
crustal melts. In contrast, during Devonian times extensive
melting of an enriched mantle led to a huge volume of
felsic magmatism and/or alternatively a different crustal
segment is involved as source of the felsic melts.
Models for the early Paleozoic tectonic evolution
of the Eastern Sierras Pampeanas
Models for the Pampean Orogeny
Two conflicting models have been proposed to explain
the (580–510 Ma) Pampean orogeny. One model follows
the concepts initially published by Ramos et al. (1986)
involving a terrane collisional model in which a terrane
(Pampia or Western Sierras Pampeanas according to dif-
ferent interpretations by Rapela et al. (1998, 2007) is
accreted to the western margin of Gondwana. The second
situation evokes a non-collisional model, which considers
that the main phase of the orogen is driven by the sub-
duction of a seismic ridge (Schwartz et al. 2008 and ref-
erences therein).
The first model evokes a collisional origin, mostly
between the Rı´o de la Plata craton (RPC) and the Pampia
Terrane as proposed by Ramos et al. (1986) and Ramos
(1988) in which the orogen was initially related to a
magmatic arc established on the Pampia Terrane prior to
the collision. Kraemer et al. (1995) revised this model and
proposed a long-lasting orogen between ca. 900 and
540 Ma. This orogen would have started with an initial
passive margin stage between the Pampia Terrane and the
Rı´o de la Plata Craton (RPC), which was followed by the
onset of an eastward subduction beneath the RPC and a
retro-arc extension, responsible for the ophiolitic belts
invoked by these authors. The end of this process was
outlined with the collision of these landmasses and the
482 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
setting for the Puncoviscana Basin, which would have
worked as a peripheral foreland basin. Rapela et al. (1998)
considered that the Pampean Orogeny was a short-lived
orogenic cycle (ca.10 Ma) triggered by an east-dipping
subduction beneath the RPC that would have formed a
magmatic arc in the Sierras de Co´rdoba ca. 535 Ma; fol-
lowed by the collision with the Pampean Terrane causing
high-grade metamorphism and peraluminous granitoid
emplacement at 530–520 Ma.
More recently, different interpretations as the ones
proposed by Escayola et al. (2007) or Collo et al. (2009)
reframed the collisional models influenced by Sm–Nd
isotopic data and zircon provenance patterns. Escayola et al.
(2007) proposed an initial stage in which a west dipping
subduction could have started ca. 650 Ma between the RPC
and a Grenvillian (?) Pampia terrane with the development
of a 0.6 Ma magmatic arc and a back-arc basin at the
western side of this arc. After the RPC collided with the
magmatic arc, widening of the back-arc basin continued,
and the onset of an east-dipping subduction process
underneath the arc took place. This basin would have been
closed ca. 560 Ma followed by a collisional stage between
this landmass and the Pampia terrane. According to their
interpretation, this collision (between 580 and 540 Ma)
would have caused ophiolite obduction and crustal thick-
ening, a tectonic setting with promoted decompression,
high-grade metamorphism and crustal melting between 540
and 515 Ma. On the other hand, Collo et al. (2009) had
taken into account the existence of three blocks in the
Eastern Sierras Pampeanas: a Brasiliano arc, Co´rdoba
Terrane and the Pampia Terrane. In this case, the orogeny
would have been caused by subsequent collisions and the
ultimate closure of the Puncoviscana ocean *530 Ma.
The other hypotheses consider that the Pampean orogeny
could have been formed as a non-collisional orogen.
According to Schwartz et al. (2008), the orogenic evolution
started with a long-lived early subduction between 555 and
525 Ma that would have built a calc-alkaline magmatic arc,
which could partially provide the sediments to build a long
accretionary prism. This scenario could have been subject
either to: (1) a subduction rollback episode, (2) a partial
density-driven subduction-thickened lower lithosphere or
(3) a subduction of a mid-ocean spreading center to produce
the short-lived pulse of high-grade metamorphism and
peraluminous/mafic magmatism in the accretionary prism.
However, these authors conclude that the most plausible
option would be the one that involves the subduction of a
seismic ridge beneath the accretionary prism developed in
the RPC, excluding a continental collision (Schwartz and
Gromet 2004) and the existence of the Pampia craton. As
noted previously by Escayola et al. (2007), all these models
have two statements in common: (1) the subduction of
oceanic lithosphere was east dipping beneath the RPC, and
(2) the supracrustal sequences of the Eastern Pampean
Ranges represent the passive/active margin deposits along
the continental platform of that craton.
On the basis of a geochronological study in the RPC,
Rapela et al. (2007) proposed that these supracrustal
sequences or protoliths of the metasedimentary rocks of the
ESP could have been initially deposited as large submarine
fans at the southern tip of the RPC and the Kalahari craton
and fed by a magmatic arc located at the present African
side. They conclude that the closing of the Clymene Ocean
(Trindade et al. 2006), which might have separated the
RPC from the Grenvillian terranes such as Amazonia,
Arequipa-Antofalla and Western Sierras Pampeanas, would
have led to a right-lateral accretion of a Western Sierras
Pampeanas Terrane (namely Cuyania without the Pre-
cordillera Terrane in the sense of Ramos (2008)) to create
the Pampean belt at *540–520 Ma. After the collision, a
continued right-lateral movement would have displaced the
Pampean mobile belt to its present position alongside the
Rı´o de la Plata Craton through the dextral Trans-Brasiliano
shear zone. Following these ideas, Drobe et al. (2009)
proposed that the PMC and NMC, in the Sierras de San
Luis, might have been deposited since 515 Ma, as an infill
of the post-Pampean back-arc basins. Recently, new pre-
cise geochronological data allowed Siegesmund et al.
(2010) to invoke a two-stage model determining the onset
of metamorphism at 550–540 Ma and the docking of a
Mesoproterozoic terrane ca. 530 Ma.
Models for the Famatinian Orogeny
The evolution and geodynamic setting of the Sierras
Pampeanas during the Ordovician was essentially consid-
ered a collisional orogeny (Fig. 7). The (500–440 Ma)
Famatinian orogen consists of a continuous upper-plate
continental arc, associated with some contribution from
juvenile mantle material and ensialic basins (Collo et al.
2009; Dahlquist et al. 2008), which stretched between
southern Peru and northern Patagonia (Casquet et al. 2006;
Chew et al. 2007; Martı´nez Dopico et al. 2010). The first
collisional model (Ramos 1988) invokes the collision of
the Laurentia-derived Precordillera/Cuyania Terrane,
which docked with the proto-Andean margin of Gondwana
in the mid to late Ordovician (Thomas and Astini 2003 and
references therein). More recently, Dahlquist et al. (2008)
proposed a model for the development of a relatively short-
lived (481–463 Ma) Famatina Complex (Famatina mag-
matic arc and related ensialic basins) along the border of
the Pampean basement, related with an ongoing subduction
along the margin of their Western Sierras Pampeanas
Terrane. Although magmatism and closure of the ensialic
basin were related to a compressive event, no indication of
the geodynamic setting of the compression was addressed.
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 483
123
Another hypothesis invokes a parautochthonous model,
where the Cuyania Terrane (sedimentary sequence of the
Precordillera of Argentina plus Grenville basement of the
Western Sierras Pampeanas) migrated along a transform
fault, from a position on the southern margin of West
Gondwana (present coordinates) in the mid-Ordovician to
its modern position outboard of the Famatina magmatic belt
in Devonian time (Finney 2007 and references therein).
The interval between the end of the Pampean orogen and
the initiation of the Famatinian subduction encompasses the
uplift and erosion of the Pampean-related rocks that feed
middle Cambrian foreland basins like the original basin of
the PMC (which developed along the margin of the Pam-
pean terrane) and the initiation of a new subduction along
the western margin of the Pampean terrane. Collo et al.
(2009) proposed that these foreland basins received con-
tributions from the contemporaneous early Cambrian
Pampean volcanism from the east (e.g. tuffs in the San Luis
Formation) and from partially exhumed I-type granitoids.
The first deformation and metamorphism in these basins
was related to the onset of the Famatina subduction at
around 500 Ma. Subsequently, an extensional ensialic
back-arc regime was established. The initiation of granulite-
facies metamorphism due to the transient anomaly associ-
ated with the 506–480 Ma mafic and ultramafic intrusions is
contemporaneous or closely followed by the emplacement
of crustal derived granitoids, such as the northern stock of
the 491 Ma Paso del Rey granite and the 480–460 Ma OTS
Fig. 7 Schematic evolution of the Eastern Sierras Pampeanas
between 30 and 32 SL from the Neoproterozoic to the Silurian.
a Back-arc extension according to Escayola et al. (2007) and data
from this paper, Table 2. Note that arc magmatism is developed in an
inferred Arequipa derived block. Location of this margin close to the
Kalahari craton is taken from Rapela et al. (2007). b Initial
development of an accretionary prism along an active margin that
started after the closure of the Adamastor ocean. Ages to constrain an
older metamorphic overprint are taken from Sims et al. (1998) and
Siegesmund et al. (2010). c Late Neoproterozoic to early Cambrian
development of the Sierra Norte arc magmatism and concomitant
deposition of accretionary prism sediments. d Deformation of the
accretionary prism (Puncoviscana Formation equivalent) and cessa-
tion of arc magmatism. Ridge subduction hypothesis and ages for the
magmatism are taken from Schwartz et al. (2008). Final closure of the
orogen e is ascribed to the accretion of a slice of Mesoproterozoic
basement that may correspond to the Western Sierras Pampeanas
Terrane or Pampia. The evidence for an Arequipa—Antofalla
connection for this basement seems feasible (Casquet et al. 2008)
but timing of accretion remains dubious. f Displacement of the
Pampean belt from the original situation as an apron along the
Kalahari margin to its final position facing the Rı´o de la Plata Craton,
which took place after ridge collision and during WSP accretion
(Rapela et al. 2007). g Initiation of the subduction that migrated to
the western border of the Pampean belt. Incipient development of
extensional basins. Age constraints for the initiation of sedimentation
are interpreted from the detrital data of Steenken et al. (2006),
Siegesmund et al. (2010) and Drobe et al. (2009, 2010 this volume).
h Accretion of the Precordillera Terrane. Age constraints for the
Pringles Metamorphic Complex were taken from Steenken et al.
(2006). Synorogenic deposition of Negro Peinado and Achavil
Formations according to Collo et al. (2009). i Post-Famatinian
margin of Gondwana. j Convergence of Chilenia based on Ramos
(1988)
484 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
tonalite-granodiorite in the low-grade phyllites. The pro-
nounced crustal signatures of both mafic and felsic rocks
may indicate that the deeper exposed crustal levels of the
PMC may show roots of the Famatinian arc. Delpino et al.
(2007) proposed that a late compressional regime devel-
oped NNE trending shear zones which controlled the
exhumation of the Ordovician complex.
Collo et al. (2009) suggested that the initiation of the
Famatinian orogenic cycle could correspond to the Iruyic
unconformity in NW Argentina. Extensional basins post-
dating the initiation of the Famatinan arc were developed
along the entire margin of the Pampean terrane (Collo et al.
2009).
Models for the Achalian Orogeny
The (400–350 Ma) Achalian orogeny (or the Achalian
cycle, Sims et al. 1997) resulted from the collision of the
allochthonous Chilenia Terrane with Gondwana (Fig. 7)
(Ramos et al. 1986; Ramos 1988; Sims et al. 1997, 1998;
Davis et al. 1999; Quenardelle and Ramos 1999). This event
roughly corresponds to the late to post-Famatinian events
of the Famatinian cycle of Dalla Salda et al. (1998). The
Achalian orogeny is a period of heterogeneous deformation
due to crustal scale shear zones that may have resulted from
the resumption of the convergence on the western margin of
Gondwana (Siegesmund et al. 2004). Achalian granitoids
intruded the older basement and are especially widespread
in the Sierra de San Luis and the Sierras de Co´rdoba (Sims
et al. 1997; Siegesmund et al. 2004; Lo´pez de Luchi et al.
2007; Rapela et al. 2007). The large Devonian intrusions of
the Sierras de Co´rdoba, i.e. the Achala and Cerro Aspero
batholiths, show typical post-tectonic emplacement char-
acteristics, like the highly discordant contact with the host
rocks (Pinotti et al. 2006), suggesting that the block of the
Sierras de Co´rdoba behaved as a rigid indenter during the
accretion processes to the western outboard of Gondwana
The voluminous Achalian granitic magmatism has raised
much speculation regarding the underlying geodynamic
causes (Lo´pez de Luchi et al. 2007 and references therein).
It was first discussed as post-tectonic in relation to the
Famatinian cycle (Llambı´as et al. 1998; Dalla Salda et al.
1998) or as resulting from mafic underplating (Lo´pez de
Luchi 1996, Lo´pez de Luchi et al. 2007). Alternatively, it
can be proposed that this magmatism results from slab
break-off during the late stages of the subduction that ended
with the collision of Chilenia.
Acknowledgments We are grateful for the support by the German
Science Foundation that funded our research projects in Argentina
over the years (Grant Si 438/17 and Si 438/24) as well as to the
DAAD-ANTORCHAS programm. A. Steenken is also grateful for
the DFG research scholarship (Ste 1036/1) and the Feodor-Lynen
Fellowship V.3/FLF/1116298 from the Alexander von Humboldt
Foundation.M. Lo´pez de Luchi thanks DAAD support through DAAD
grants A/03/39422 and A/07/10368. Dr Zimmermann, Dr Basei and
an anonymous reviewer are thanked for their helpful comments.
References
Acen˜olaza F, Toselli AJ (1977) Esquema geolo´gico de la Sierra de
Ancasti, provincia de Catamarca. Acta Geolo´gica Lilloana
14:233–256
Acen˜olaza FG, Toselli AJ (1981) Geologı´a del Noroeste Argentino.
Publicacio´n Especial de la Facultad de Ciencias Naturales,
Universidad Nacional de Tucuma´n 1287:1–212
Anzil PA, Martino RD (2009) The megascopic and mesoscopic
structure of La Cocha ultramafic body, Sierra Chica of Co´rdoba,
Argentina. J S Am Earth Sci 28(4):398–406
Arndt NT, Goldstein SL (1987) Use and abuse of crust-formation
ages. Geology 15(10):893–895
Astini RA, Da´vila FM, Collo G (2008) Las discordancias Tilca´rica e
Iru´yica en el noroeste argentino: una perspectiva regional.
XVIII. Congr Geol Argent Actas I:3–4
Ba´ez MA, Bellos LI, Grosse P, Sardi FG (2005) Caracterizacio´n
petrolo´gica de la Sierra de Velasco. In: Dahlquist J, Rapela C,
Baldo E (eds) Geologı´a de la provincia de La Rioja-Preca´mb-
rico-Paleozoico Inferior. Asoc Geol Argent Spec Pub Serie D
8:123–130
Baldo E, Casquet C, Galindo C (1996) El metamorfismo de la Sierra
Chica de Co´rdoba (Sierras Pampeanas) Argentina. Geogaceta
19:51–54
Balhburg H (1991) The Ordovician back-arc to foreland successor
basin in the Argentinian—Chilean Puna: tectonosedimentary
trends and sea-level changes. In: MacDonald DIM (ed) Sedi-
mentation, tectonics, and eustasy. Spec Pub Inter Assoc Sedi-
mentol 12:465–484
Bellos LI (2005) Geologı´a y petrologı´a del sector austral de la sierra
de Velasco, al sur de los 29 44’S, La Rioja, Argentina. In:
Acen˜olaza FG, Hu¨nicken M, Toselli AJ, Acen˜olaza GF (eds)
Simposio Bodenbender: Trabajos completos. Serie de Correla-
cio´n Geolo´gica, N8 19. INSUGEO (CONICET). San Miguel de
Tucuma´n, 261–278
Bonalumi A, Martino R, Sfragulla J, Carignano C, Tauber A (2001)
Hoja Geolo´gica 3363-I. VILLA MARIA. (Memory and Geologic
map). Instituto de Geologı´a y Recursos Minerales -SEGEMAR,
Buenos Aires
Boynton WV (1984) Geochemistry of the rare-earth elements:
meteorite studies. In: Henderson P (ed) Rare earth element
geochemistry. Elsevier, New York, pp 63–114
Bu¨ttner SH, Glodny J, Lucassen F, Wemmer K, Erdmann S, Handler
R, Franz G (2005) Ordovician metamorphism and plutonism in
the Sierra de Quilmes metamorphic complex: Implications for
the tectonic setting of the northern Sierras Pampeanas (NW
Argentina). Lithos 83(1–2):143–181
Casquet C, Baldo E, Pankhurst RJ, Rapela CW, Galindo C, Fanning
CM, Saavedra J (2001) Involvement of the Argentine Precord-
illera Terrane in the Famatinian mobile belt: U-Pb SHRIMP and
metamorphic evidence from the Sierra de Pie de Palo. Geology
29:703–706
Casquet C, Pankhurst RJ, Fanning CM, Baldo E, Galindo C, Rapela
C, Gonza´lez-Casado JM, Dahlquist JA (2006) U–Pb SHRIMP
zircon dating of Grenvillian metamorphism in Western Sierras
Pampeanas (Argentina): correlation with the Arequipa Antofalla
craton and constraints on the extent of the Precordillera Terrane.
Gondwana Res 9:524–529
Casquet C, Pankhurst RJ, Rapela C, Galindo C, Fanning CM,
Chiaradia M, Baldo E, Gonza´lez-Casado JM, Dahlquist JA
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 485
123
(2008) The Maz terrane: a Mesoproterozoic domain in the
western Sierras Pampeanas (Argentina) equivalent to the Arequ-
ipa-Antofalla block of southern Peru? implications for Western
Gondwana margin evolution. Gondwana Res 13:163–175
Chew DM, Schaltegger U, Kosler J, Whitehouse MJ, Gutjahr M,
Spikings RA, Miskovic A (2007) U–Pb geochronologic evidence
for the evolution of the Gondwanan margin of the north–central
Andes. GSA Bull 119:697–711
Collo G, Astini RA, Cardona A, Do Campo MD, Cordani U (2008)
Edades de metamorfismo en las unidades con bajo grado de la
regio´n central del Famatina: la impronta del ciclo oroge´nico
oclo´yico (Ordovı´cico). Rev Geol Chil 35(2):191–213
Collo G, Astini RA, Cawood P, Buchan C, Pimentel M (2009) U-Pb
detrital zircon ages and Sm-Nd isotopic features in low-grade
metasedimentary rocks of the Famatina belt: implications for late
Neoproterozoic-Early Paleozoic evolution of the proto-Andean
margin of Gondwana. J Geol Soc London 166:303–319
Dahlquist JA, Pankhurst RJ, Rapela CW, Galindo C, Alasino P,
Fanning CM, Saavedra J, Baldo E (2008) New SHRIMP U-Pb
data from the Famatina Complex: constraining Early–Mid
Ordovician Famatinian magmatism in the Sierras Pampeanas,
Argentina. Geol Acta 6(4):319–333
Dalla Salda LH, Lo´pez de Luchi MG, Cingolani CA, Varela R (1998).
Laurentia-Gondwana collision: the origin of the Famatinian-
Appalachian Orogenic Belt (a review). In: Pankhurst RJ, Rapela
CW (eds) The Proto-Andean Margin of Gondwana. Geol Soc
London Spec Pub 142:219–234
Davis JS, Roeske SM, Mc Clelland WC (1999) Closing the ocean
between the Precordillera Terrane and Chilenia: Early Devonian
ophiolite emplacement and deformation in the southwest
Precordillera. In: Ramos VA, Keppie JD (eds) Laurentia-
Gondwana connections before Pangea. GSA Spec Pap
336:115–138
de Brodtkorb MK, Ostera H, Pezzutti N, Tassinari C (2005) Sm/Nd
and K-Ar data from W-bearing amphibolites of Eastern Pampean
Ranges, San Luis and Co´rdoba, Argentina. V S Am Symp
Isotope Geol, pp 478–482
Delpino SH, Bjerg EA, Ferracutti GR, Mogessie A (2007) Counter-
clockwise tectonometamorphic evolution of the Pringles Meta-
morphic Complex, Sierras Pampeanas of San Luis (Argentina).
J S Am Earth Sci 23:147–175
Drobe M, Lo´pez de Luchi MG, Steenken A, Frei R, Naumann R,
Wemmer K, Siegesmund S (2009) Provenance of the Late
Proterozoic to Early Cambrian metaclastic sediments of the
Sierra de San Luis (Eastern Sierras Pampeanas) and Cordillera
oriental, Argentina. J S Am Earth Sci 28:239–262
Drobe M, Lo´pez de Luchi MG, Steenken A, Wemmer K, Naumann R,
Frei R, Siegesmund S (2010) Geodynamic evolution of the
Eastern Sierras Pampeanas (Central Argentina) based on
geochemical, Sm-Nd, Pb-Pb and SHRIMP data. doi:10.1007/
s00531-010-0593-3
Escayola M, Rame´ G, Kraemer PE (1996) Caracterizacio´n y
significado tecto´nico de las fajas ultrama´ficas de las Sierras
Pampeans de Co´rdoba. XIII Congr Geol Argent Actas:421–438
Escayola MP, Pimentel MM, Armstrong R (2007) Neoproterozoic
back-arc basin: sensitive high-resolution ion microprobe U–Pb
and Sm–Nd isotopic evidence from the Eastern Pampean
Ranges, Argentina. Geology 35:495–498
Fagiano M, Otamendi JE, Nullo F (2008) Los oro´genos Pampeano y
Famatiniano en la evolucio´n de los complejos Monte Guazu´ y
Achiras, Sierra de Comechingones, Co´rdoba. XVIII Congr Geol
Argent, Jujuy, Actas:1008–1009
Finney SC (2007) The parautochthonous Gondwanan origin of the
Cuyania (greater Precordillera) terrane of Argentina: a reeval-
uation of evidence used to support an allochthonous Laurentian
origin. Geol Acta 5:127–158
Gaido MF (2003) Informe petrogra´fico de la hoja geolo´gica Recreo
2966-IV, escala 1:250.000. Servicio Geolo´gico Minero Argen-
tino, delegacio´n Co´rdoba, 12 pp
Gonza´lez PD, Sato AM, Llambı´as EJ, Basei MAS, Vlach SRF (2004)
Early Paleozoic structural and metamorphic evolution of western
Sierra de San Luis (Argentina), in relation to Cuyania Accretion.
Gondwana Res 7:1157–1170
Gonza´lez PD, Sato AM, Llambı´as EJ, Petronilho LA (2009) Petrology
and geochemistry of the banded iron formation in the Eastern
Sierras Pampeanas of San Luis (Argentina): implications for the
evolution of the Nogolı´ Metamorphic complex. J S Am Earth Sci
28(2):89–112
Gordillo CE (1984) Migmatitas cordierı´ticas de la sierra de Co´rdoba;
condiciones fı´sicas de la migmatizacio´n. Academia Nacional de
Ciencias, Co´rdoba. Miscela´nea 68:1–40
Gromet LP, Simpson C, Miro R, Whitmeyer SJ (2001) Apparent
truncation and juxtaposition of Cambrian and Ordovician arc-
accretionary complexes, Eastern Sierras Pampeanas, Argentina.
Geol Soc Am Annual Meeting, Abstracts with Programs, vol 33.
Boston, p A-155
Grosse P, So¨llner F, Ba´ez MA, Toselli AJ, Rossi JN, de la Rosa D
(2008) Lower Carboniferous post-orogenic granites in central-
eastern Sierra de Velasco, Sierras Pampeanas, Argentina: U-Pb
monazite geochronology, geochemistry and Sr-Nd isotopes. Inter
J Earth Sci 98(5):1001–1025
Guereschi A, Martino RD (2008) Field and textural evidence of two
migmatization events in the Sierras de Co´rdoba, Argentina.
Gondwana Res 13:176–188
Hauzenberger C, Mogessie A, Hoinkes G, Felfernig A, Bjerg E,
Kostadinoff J, Delpino S, Dimieri L (2001) Metamorphic evolution
of the Sierras de San Luis, Argentina: Granulite facies metamor-
phism related to mafic intrusions. Mineral Petrol 71(1–2):95–126
Kay S, Orrell S, Abbruzzi JM (1996) Zircon and whole rock Nd–Pb
isotopic evidence for a Grenville Age and a Laurentian origin for
the basement of the Precordillera in Argentina. J Geol
104:637–648
Knu¨ver M (1983) Dataciones radime´tricas de rocas pluto´nicas y
metamo´rficas. In: Acen˜olaza FG, Miller H, Toselli J (eds)
Geologı´a de la sierra de Ancasti, Mu¨nstersche Forschungen zur
Geologie und Pa¨laontologie, vol 59. Heft, Mu¨nster, pp 201–218
Kostadinoff J, Bjerg E, Delpino S, Dimieri L, Mogessie A, Hoinkes
G, Hauzenberger C, Felfernig A (1998) Gravimetric and
magnetometric anomalies in the Sierras Pampeanas of San Luis.
Rev Asoc Geol Argent 53(4):549–552
Kraemer PE, Escayola MP, Martino RD (1995) Hipo´tesis sobre la
evolucio´n neoproterozoica de las Sierras Pampeanas de Co´rdoba
(30 840–32 840S) Argentina. Rev Asoc Geol Argent 50(1–4):47–59
Kretz R (1983) Symbols for rock-forming minerals. Am Mineral
68:277–279
Krol MA, Simpson C (1999) Thermal history of the eastern Sierras
Pampeanas accretionary prism rocks, constraints from 40Ar/39Ar
mica data. GSA Abs Program 31(7):114–115
Lira R, Millone HA, Kirschbaum A, Moreno RS (1997) Calc-alkaline
arc granitoid activity in the sierra Norte-Ambargasta ranges,
central Argentina. J S Am Earth Sci 10:157–177
Llambı´as EJ, Sato AM, Ortiz Sua´rez A, Prozzi C (1998) The
granitoids of the Sierra de San Luis. In: Pankhurst RJ, Rapela
CW (eds) The Proto-Andean Margin of Gondwana. Geol Soc
London Spec Pub 142:325–341
Llambı´as EJ, Gregori D, Basei MAS, Varela R, Prozzi C (2003)
Ignimbritas riolı´ticas neoproterozoicas en la Sierra Norte de
Co´rdoba: evidencia de un arco magma´tico temprano en el ciclo
Pampeano? Rev Asoc Geol Argent 58(4):572–582
Lo´pez de Luchi MG (1996) Enclaves en un batolito postecto´nico:
petrologı´a de los enclaves microgranulares del batolito de Renca.
Rev Asoc Geol Argent 51(2):131–146
486 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123
Lo´pez de Luchi MG, Favetto A, Pomposiello MC, Booker J (2005)
Magnetotelluric evidence for the suture between the Rı´o de la
Plata and the Pampean cratons at 318 400, Co´rdoba province,
Argentina. VI Int Symp Andean Geodynamics, (ISAG 2005,
Barcelona), Extended abstracts, pp 446–449
Lo´pez de Luchi MG, Siegesmund S, Wemmer K, Steenken A,
Naumann R (2007) Geochemical constraints on the petrogenesis
of the Palaeozoic granitoids of the Sierra de San Luis, Sierras
Pampeanas, Argentina. J S Am Earth Sci 24:138–166
Martı´nez Dopico CI, Lo´pez de Luchi MG, Rapalini AE, Kleinhanns
IC (2010) Distinguishing crustal segments in the North Patago-
nian Massif, Patagonia: an integrated perspective based on Nd
systematics. J S Am Earth Sci doi:10.1016/j.jsames.2010.07.009
(in press)
Martino RD (2003) Las fajas de deformacio´n du´ctil de las Sierras
Pampeanas de Co´rdoba: una resen˜a general. Rev Asoc Geol
Argent 58:549–571
Martino R, Kraemer P, Escayola M, Giambastiani M, Arnosio M
(1995) Transecta de las sierras Pampeanas de Co´rdoba a los 32
LS. Rev Asoc Geol Argent 50:60–77
Miller H, So¨llner F (2005) The Famatinian complex (NW Argentina):
back-docking of an island arc or terrane accretion? Early
Palaeozoic geodynamics at the western Gondwana margin. In:
Vaughan APM, Leat PT, Pankhurst RJ (eds) Terrane Processes
at the Margins of Gondwana, vol 246. Geol Soc London Spec
Pub, pp 241–256
Millone HA, Tassinari CCG, Lira R, Poklepovic MF (2003) Age and
neodymium isotope geochemistry of granitoids of the Sierra
Norte-Ambargasta Batholith, Central Argentina, vol I. IV S Am
Symp Isotope Geol Actas, pp 617–620
Mutti DI (1987) Estudio geolo´gico del Complejo Gabro-Peridotı´tico
del a´rea de Bosque Alegre, Co´rdoba. PhD Thesis, University of
Buenos Aires 189 p (unpublished)
Mutti DI (1992) El Complejo gabro-peridotı´tico de Bosque Alegre,
Provincia de co´rdoba. Rev Asoc Geol Argent 47(2):153–167
Otamendi JE, Nullo FE, Patin˜o Douce AE, Fagiano MR (1998)
Geology, mineralogy and geochemistry of syn-orogenic anatec-
tic granites from the Achiras Complex, Co´rdoba; Argentina:
some petrogenetic and geodynamic implications. J S Am Earth
Sci 11(4):407–423
Otamendi JE, Fagiano MR, Nullo FE (2000) Geologı´a y evolucio´n
metamo´rfica del Complejo Monte Guazu´, sur de la sierra de
Comechingones, provincia de Co´rdoba. Rev Asoc Geol Argent
55(3):265–279
Otamendi JE, Castellarini PA, Fagiano MR, Demichelis AH, Tibaldi
AM (2004) Cambrian to Devonian geologic evolution of the
Sierra de Comechingones, Eastern Sierras Pampeanas, Argen-
tina: evidence for the developments and exhumation of conti-
nental crust on the Proto-Pacific Margin of Gondwana.
Gondwana Res 7:1143–1155
Otamendi JE, Demichelis A, Tibaldi A, de la Rosa J (2006) Genesis
of aluminous and intermediate granulites: a study case in the
eastern Sierras Pampeanas, Argentina. Lithos 89:66–88
Pankhurst RJ, Rapela CW, Saavedra J, Baldo E, Dahlquist J, Pascua I,
Fanning CM (1998) The Famatinian magmatic arc in the central
Sierras Pampeanas: an Early to Mid-Ordovician continental arc
on the Gondwana margin. In: Pankhurst RJ, Rapela CW (eds)
The Proto-Andean Margin of Gondwana, vol 142. Geol Soc
London Spec Pub, pp 343–367
Pankhurst RJ, Rapela CW, Fanning CM (2000) Age and origin of
coeval TTG, I- and S-type granites in the Famatinian belt of NW
Argentina. Royal Soc Edinburgh Trans Earth Sci 91:151–168
Pinotti LP, Coniglio JE, Esparza AM, D’Eramo FJ, Llambias EJ
(2002) Nearly circular plutons emplaced at shallow crustal
levels, Cerro Aspero batholith, Sierras Pampeanas de Co´rdoba,
Argentina. J S Am Earth Sci 15:251–265
Pinotti L, Tubı´a JM, D’Eramo F, Vegas N, Sato AM, Coniglio J,
Aranguren A (2006) Structural interplay between plutons during
the construction of a batholith (Cerro Aspero batholith, Sierras
de Co´rdoba, Argentina). J Struc Geol 28:834–849
Prozzi CR, Ramos G (1988) La Formacio´n San Luis. In: Primeras
Jornadas de trabajo de Sierras Pampeanas, San Luis Abstracts, p 1
Quenardelle S, Ramos VA (1999) Ordovician western Sierras
Pampeanas magmatic belt: record of Precordillera accretion in
Argentina. In: Ramos VA, Keppie JD (eds) Laurentia–Gondw-
ana Connections before Pangea, vol 336. GSA, Spec Pap,
pp 63–86
Ramos VA (1988) Late Proterozoic-early Paleozoic of South
America: a collisional story. Episodes 11:168–174
Ramos VA (2008) The basement of the Central Andes: the Arequipa
and related terranes. An Rev Earth Planet Sci 36:289–324
Ramos VA, Jordan TE, Allmendinger W, Mpodozis C, Kay SM,
Corte´s JM, Palma M (1986) Paleozoic terranes of the Central
Argentine–Chilean Andes. Tectonics 5:855–880
Ramos VA, Escayola M, Mutti DI, Vujovich GI (2000) Proterozoic–
early Paleozoic ophiolites of the Andean basement of southern
South America. GSA Spec Pap 349:331–349
Rapela CW (2000) The Sierras Pampeanas of Argentina: Paleozoic
building of the southern Proto-Andes. In: Cordani UG, Milani EJ,
Thomas-Filho A, Campos DA (eds) Tectonic Evolution of South
America. XXXI8 Inter Geol Congr, Rı´o de Janeiro, pp 381–387
Rapela CW, Toselli AJ, Heaman L, Saavedra J (1990) Granite
plutonism of the Sierras Pampeanas: an inner cordilleran
Paleozoic arc in the southern Andes. GSA Spec Pap 241:77–90
Rapela CW, Pankhurst RJ, Bonalumi AA (1991) Edad y geoquı´mica
del Po´rfido Granı´tico de Onca´n, sierra Norte de Co´rdoba, Sierras
Pampeanas, Argentina. VI Congr Geol Chil, Vin˜a del Mar, Actas
1:19–22
Rapela CW, Pankhurst RJ, Casquet C, Baldo E, Saavedra J, Galindo
C, Fanning CM (1998) The Pampean Orogeny of the southern
proto-Andes: Cambrian continental collision in the Sierras de
Co´rdoba. In: Pankhurst RJ, Rapela CW (eds) The Proto-Andean
margin of Gondwana, vol 142. Geol Soc London Spec Pub,
pp 181–217
Rapela CW, Pankhurst RJ, Casquet C, Baldo E, Galindo C, Fanning
CM, Saavedra J (2001) Ordovician metamorphism in the Sierras
Pampeanas: new U-Pb SHRIMP ages in central-east Valle Fe´rtil
and the Velasco Batholith, vol 1. III S Am Symp Isotope Geol,
pp 616–619
Rapela CW, Baldo EG, Pankhurst RJ, Saavedra J (2002) Cordierite
and Leucogranite Formation during Emplacement of Highly
Peraluminous Magma: the El Pilo´n Granite Complex (Sierras
Pampeanas, Argentina). J Petrol 43(6):1003–1028
Rapela CW, Fanning M, Baldo E, Dahlquist J, Pankhurst RJ, Murra J
(2005) Coeval S- and I-type granites in the Sierra de Ancasti,
Eastern Sierras Pampeanas, Argentina. In: Pankhurst RJ, Veiga
G (eds) Gondwana 12: Geol Biol Herit Gondwana, Abstract,
pp 307
Rapela CW, Pankhurst RJ, Casquet C, Fanning CM, Baldo EG,
Gonza´les-Casado JM, Galindo C, Dahlquist J (2007) The Rı´o de
la Plata craton and the assembly of Gondwana. Earth Sci Rev
83:49–82
Rapela CW, Baldo EG, Pankhurst RJ, Fanning CM (2008) The
Devonian Achala Batholith of the Sierras Pampeanas: F-rich
aluminous A-type granites VI S, vol 1. Am Symp Isotope Geol,
p 104
Reissinger M (1983) Geologı´a de la Sierra de Ancasti. Evolucio´n
geoquı´mica de las rocas pluto´nicas. Munster Forsch Geol
Palaont 59:101–112
Rossi JN, Toselli AJ, Ba´ez MA (2005) Evolucio´n termoba´rica del
ortogneis peraluminoso del noroeste de la sierra de Velasco, La
Rioja. Rev Asoc Geol Argent 60(2):278–289
Int J Earth Sci (Geol Rundsch) (2011) 100:465–488 487
123
Sato AM, Gonza´lez P, Sato K (2001). First indication of Mesopro-
terozoic age from the western basement of the Sierra de San
Luis, Argentina, vol 1. III S Am Symp Isotope Geol, pp 64–67
Sato AM, Gonza´lez PD, Llambı´as EJ (2003) Evolution of the
Famatinian orogen in the Sierra de San Luis: arc magmatism,
deformation, and low to high-grade metamorphism. Rev Asoc
Geol Argent 58:487–504
Schwartz JJ, Gromet LP (2004) Provenance of a late Proterozoic–
early Cambrian basin, Sierras de Co´rdoba, Argentina. Precambr
Res 129:1–21
Schwartz JJ, Gromet LP, Miro R (2008) Timing and duration of the
calc-alkaline arc of the Pampean orogeny: implications for the
late Neoproterozoic to Cambrian Evolution of Western Gondw-
ana. J Geol 116:39–61
Shirey SB, Hanson GN (1986) Mantle heterogeneity and crustal
recycling in Archean granite-greenstone belts: Evidence from
Nd-isotopes and trace elements in the Rainy Lake area, Superior
province, Ontario, Canada. Geochim Cosmochim Acta
50:2631–2651
Siegesmund S, Steenken A, Lo´pez de Luchi MG, Wemmer K (2004)
The Las Chacras-Potrerillos Batholith: structural evidences on its
emplacement and timing of the intrusion. Inter J Earth Sci
93:23–43
Siegesmund S, Steenken A, Martino R, Wemmer K, Lo´pez de Luchi
MG, Frei R, Presniakov S, Guereschi A (2010) Time constraints
on the tectonic evolution of the Eastern Sierras Pampeanas
(Central Argentina). Int J Earth Sci. doi:10.1007/s00531-
009-0471-z
Sims JP, Skirrow RG, Stuart-Smith PG, Lyons P (1997) Informe
geolo´gico y metalogene´tico de las Sierras de San Luis y
Comechingones (provincias de San Luis y Co´rdoba), 1:250000.
Anales 28. IGRM, SEGEMAR, Buenos Aires, pp 1–148
Sims JP, Ireland TR, Camacho A, Lyons P, Pieters PE, Skirrow RG,
Stuart-Smith PG, Miro´ R (1998) U–Pb, Th–Pb and Ar–Ar
geochronology form the southern Sierras Pampeanas: implica-
tion for the Palaeozoic tectonic evolution of the western
Gondwana margin. In: Pankhurst RJ, Rapela CW (eds) The
Proto-Andean Margin of Gondwana, vol 142. Geol Soc London
Spec Pub, pp 259–281
Spear FS, Kohn MJ, Cheney JT (1999) P-T paths from anatectic
pelites. Contrib Mineral Petrol 134:17–32
Steenken A, Lo´pez de Luchi MG, Siegesmund S, Wemmer K, Pawlig
S (2004) Crustal provenance and cooling of the basement
complexes of the Sierra de San Luis: an insight into the tectonic
history of the proto-Andean margin of Gondwana. Gondwana
Res 7(4):1171–1195
Steenken A, Lo´pez de Luchi MG, Siegesmund S, Wemmer K (2005)
The thermal impact of the accommodation of mafic melts within
the central basement complex of the Sierra de San Luis:
constraints from numeric modeling. XVI8 Congr Geol Argent,
La Plata. Actas 1:889–896
Steenken A, Siegesmund S, Lo´pez de Luchi MG, Frei R, Wemmer K
(2006) Neoproterozoic to early Palaeozoic events in the Sierra de
San Luis: implications for the Famatinian geodynamics in the
Eastern Sierras Pampeanas (Argentina). J Geol Soc London
163:965–982
Steenken A, Siegesmund S, Wemmer K, Lo´pez de Luchi MG (2008)
Time constraints on the Famatinian and Achalian structural
evolution of the basement of the Sierra de San Luis (Eastern
Sierras Pampeanas, Argentina). J S Am Earth Sci 25(3):336–358
Steenken A, Wemmer K, Martino RD, Lo´pez de Luchi MG,
Guereschi A, Siegesmund S (2010) Post-Pampean cooling and
the uplift of the Sierras Pampeanas in the west of Co´rdoba
(Central Argentina). N Jb Geol Pala¨ont Abh 256:235–255
Stuart-Smith PG, Camacho A, Sims JP, Skirrow RG, Lyons P, Pieters
PE, Black LP (1999) Uranium–lead dating of felsic magmatic
cycles in the southern Sierras Pampeanas, Argentina: implica-
tions for the tectonic development of the proto-Andean Gondw-
ana margin. In: Ramos VA, Keppie JD (eds) Laurentia–
Gondwana Connections before Pangea, vol 336. GSA Spec
Pap, pp 87–114
Thomas W, Astini R (2003) Ordovician accretion of the Argentine
Precordillera terrane to Gondwana: a review. J S Am Earth Sci
16:67–79
Tibaldi AM, Otamendi JE, Gromet LP, Demichelis AH (2008) Suya
Taco and Sol de Mayo mafic complexes from the Eastern Sierras
Pampeanas, Argentina: Evidence for the emplacement of
primitive OIB-like magmas into deep crustal levels at a late
stage of the Pampean orogeny. J S Am Earth Sci 26:172–187
Toselli AJ (1990) Metamorfismo del Ciclo Pampeano. In: Acen˜olaza
FG, Miller H, Toselli AJ (eds) El Ciclo Pampeano en el Noroeste
Argentino. Universidad Nacional de Tucuma´n, Argentina, vol 4.
Serie Correlacio´n Geolo´gica, pp 81–197
Toselli AJ, Rossi de Toselli JN (1990) Plutonismo de la Formacio´n
Puncoviscana. In: Acen˜olaza FG, Miller H, Toselli AJ (eds) El
Ciclo Pampeano en el Noroeste Argentino. Universidad Nac-
ional de Tucuma´n, Argentina, vol 4. Serie Correlacio´n Geolo´g-
ica, pp 221–227
Toselli AJ, Miller H, Rossi JN, Acen˜olaza FG, So¨llner F (2005) The
Sierra de Velasco, NW Argentina, an example for polyphase
magmatism at the margin of Gondwana. XIX Colloquium on
Latin American Geosciences. Terra Nostra. Schriften der
GeoUnion Alfred-Wegener-Stiftung 05/1:125–126 (Potsdam)
Trindade RIF, D’Agrella-Filho MS, Epof I, Brito Neves BB (2006)
Paleomagnetism of early Cambrian Itabaiana mafic dikes (NE
Brazil) and the final assembly of Gondwana. Earth Planet Sci
Lett 244:361–377
Verdecchia SO, Baldo E, Benedetto L, Borghi R (2007) The first
shelly faunas from metamorphic rocks of the Sierras Pampeanas
(La Ce´bila Formation), Sierra de Ambato, Argentina): age and
paleogeographic implications. Ameghiniana 44:493–498
Vielzeuf D, Montel JM (1994) Partial melting of metagreywackes.
Part I. Fluid-absent experiments and phase relationships. Contrib
Mineral Petrol 117:375–393
von Gosen W, Prozzi C (1998) Structural evolution of the Sierra de
San Luis (Eastern Sierras Pampeanas, Argentina): implications
for the Proto-Andean margin of Gondwana. In: Pankhurst RJ,
Rapela CW (eds) The Proto-Andean Margin of Gondwana, vol
142. Geol Soc London Spec Pub, pp 235–258
Vujovich GI, Ostera HA (2003) Evidence of the Pampean cycle in the
basement of the northwestern sector of the Sierra de San Luis.
Rev Asoc Geol Argent 58:541–548
Vujovich GI, van Staal CR, Davis W (2004) Age Constraints on the
tectonic evolution and provenance of the Pie de Palo Complex,
Cuyania Composite Terrane, and the Famatinian Orogeny in the
Sierra de Pie de Palo, San Juan, Argentina. Gondwana Res
7:1041–1056
Willner A (1983) Evolucio´n metamo´rfica. In: Acen˜olaza FG, Miller
H, Toselli A (eds) Geologı´a de la Sierra de Ancasti, vol 59.
Mu¨nst Forsch Geol Pala¨ont, pp 189–200
Wu FY, Jahn BM, Wilde SA, Lo C, Yui TF, Lin Q, Ge WC, Sun DY
(2003) Highly fractionated I-type granites in NE China (II):
isotopic geochemistry and implications for crustal growth in the
Phanerozoic. Lithos 67:191–204
488 Int J Earth Sci (Geol Rundsch) (2011) 100:465–488
123