Browsing Geochemie, Mineralogie, Petrologie by Issue Date
Now showing items 1-20 of 181
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Sulfide Dissolution and Awaruite Formation in Continental Serpentinization Environments and Its Implications to Supporting Life
; Vrijmoed, J. C.; Engelmann, J. M.; ; Wiechert, U.; Rohne, R.; (Journal of Geophysical Research: Solid Earth, 2021-05-20)
Serpentinization environments are key locations that support microbial communities by the abiogenic formation of reduced species associated with peridotite alteration. Here we studied partially serpentinized peridotites ... -
Zircon and Melt Extraction From a Long‐Lived and Vertically Extensive Magma System Underneath Ilopango Caldera (El Salvador)
; ; ; Schindlbeck‐Belo, J. C.; Hernández, W.; Sims, K. W. W.; ; ; ; Wang, K.‐L.; Lee, H.‐Y.; Trumbull, R. B. (Geochemistry, Geophysics, Geosystems, 2021-05-12)
The Tierra Blanca (TB) eruptive suite comprises the last four major eruptions of Ilopango caldera in El Salvador (≤45 ka), including the youngest Tierra Blanca Joven eruption (TBJ; ∼106 km3): the most voluminous event ... -
Sulfur cycling in oceanic oxygen minimum zones
; ; Kuypers, Marcel M. M.; Yilmaz, Pelin; Lavik, Gaute; ; ; (Limnology and Oceanography, 2021-05-10)
The sulfur cycle is an important, although understudied facet of today's modern oxygen minimum zones (OMZs). Sulfur cycling is most active in highly productive coastal OMZs where sulfide‐rich sediments interact with the ... -
Structure determination of organic compounds by a fit to the pair distribution function from scratch without prior indexing
(Journal of Applied Crystallography, 2021-05-09)A method for the ab initio crystal structure determination of organic compounds by a fit to the pair distribution function (PDF), without prior knowledge of lattice parameters and space group, has been developed. The method ... -
Carbonates from the ancient world's longest aqueduct: A testament of Byzantine water management
; ; ; ; Mertz‐Kraus, Regina (Geoarchaeology, 2021-05-06)
The fourth‐ and fifth‐century aqueduct system of Constantinople is, at 426 km, the longest water supply line of the ancient world. Carbonate deposits in the aqueduct system provide an archive of both archaeological ... -
Anomalous SAXS at P12 beamline EMBL Hamburg: instrumentation and applications
(Journal of Synchrotron Radiation, 2021-05-02)Small‐angle X‐ray scattering (SAXS) is an established method for studying nanostructured systems and in particular biological macromolecules in solution. To obtain element‐specific information about the sample, anomalous ... -
Novel experimental setup for megahertz X‐ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X‐ray Free‐Electron Laser (EuXFEL)
(Journal of Synchrotron Radiation, 2021-05-02)The high‐precision X‐ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X‐ray Free‐Electron Laser is described. This includes ... -
How do secondary iron enrichments form within basaltic eucrites? An experimental approach
Rombeck, Stella;; Roszjar, Julia; ; Klemme, Stephan (Meteoritics & Planetary Science, 2021-05-02)
Some basaltic eucrites and basaltic lithologies in howardites derived from the asteroid 4 Vesta exhibit unusual secondary veinlet textures consisting mostly of fayalitic olivine and Fe‐enrichments within pyroxenes. Recent ... -
Global Trends in Air‐Water CO2 Exchange Over Seagrass Meadows Revealed by Atmospheric Eddy Covariance
; ; Barreras‐Apodaca, Aylin; ; Sanchez‐Mejia, Zulia; Tokoro, Tatsuki; ; Loza, Lucia Gutiérrez; ; Fourqurean, James; Thomas, Helmuth (Global Biogeochemical Cycles, 2021-04-28)
Coastal vegetated habitats like seagrass meadows can mitigate anthropogenic carbon emissions by sequestering CO2 as “blue carbon” (BC). Already, some coastal ecosystems are actively managed to enhance BC storage, with ... -
Northeast Siberian Permafrost Ice‐Wedge Stable Isotopes Depict Pronounced Last Glacial Maximum Winter Cooling
; ; ; ; ; ; ; (Geophysical Research Letters, 2021-04-09)
Stable isotopes (δ18O, δD) of wedge ice hold potential to reconstruct past winter climate conditions. Here, we present records of the marine isotope stages (MIS) 3 and 2 including the last Glacial maximum (LGM) from Bol’shoy ... -
Stable Biological Production in the Eastern Equatorial Pacific Across the Plio‐Pleistocene Transition (∼3.35–2.0 Ma)
; Ho, S. Ling; Meckler, A. Nele; Pross, Jörg; Fiebig, Jens; ; (Paleoceanography and Paleoclimatology, 2021-04-08)
Upwelling within the Eastern Equatorial Pacific (EEP) Ocean is a key factor for the Earth's climate because it supports >10% of the present‐day biological production. The dynamics of upwelling in the EEP across the ... -
The analysis of 226Ra in 1‐liter seawater by isotope dilution via single‐collector sector‐field ICP‐MS
; Geibert, Walter; Stimac, Ingrid; Koehler, Dennis; Rutgers van der Loeff, Michiel M. (Limnology and Oceanography: Methods, 2021-04-03)
The precise determination of radium‐226 (226Ra) in environmental samples is challenging due to its low concentration. Seawater typically contains between 0.03 and 0.1 fg g−1 226Ra. Thus, this work addresses the need for ... -
Comparison and evaluation of pair distribution functions, using a similarity measure based on cross‐correlation functions
(Journal of Applied Crystallography, 2021-03-31)An approach for the comparison of pair distribution functions (PDFs) has been developed using a similarity measure based on cross‐correlation functions. The PDF is very sensitive to changes in the local structure, i.e. ... -
Metapelite from the high‐ to ultrahigh‐pressure terrane of the Eastern Alps (Pohorje Mountains, Slovenia)—New pressure, temperature and time constraints on a polymetamorphic rock
; Massonne, Hans‐Joachim; Koller, Friedrich; Zhang, Junfeng (Journal of Metamorphic Geology, 2021-03-31)
The Austroalpine nappe stack of the Pohorje Mountains (Mts.) in northeastern Slovenia comprises a suite of eclogite facies metamorphic rocks that were partially assigned to Eo‐Alpine ultrahigh‐pressure metamorphism (UHPM). ... -
Numerically stable form factor of any polygon and polyhedron
(Journal of Applied Crystallography, 2021-03-25)Coordinate‐free expressions for the form factors of arbitrary polygons and polyhedra are derived using the divergence theorem and Stokes's theorem. Apparent singularities, all removable, are discussed in detail. Cancellation ... -
A discussion on `Domain formation and phase transitions in the wurtzite‐based heterovalent ternaries: a Landau theory analysis'
Quayle, Paul C.; (Acta Crystallographica Section A, 2021-03-23)
Heterovalent ternary nitrides are considered one of the promising classes of materials for photovoltaics, combining attractive physical properties with low toxicity and element abundance. One of the front‐runner systems ... -
Symmetry relations in wurtzite nitrides and oxide nitrides and the curious case of Pmc21
; Schorr, Susan (Acta Crystallographica Section A, 2021-03-23)
Binary III–V nitrides such as AlN, GaN and InN in the wurtzite‐type structure have long been considered as potent semiconducting materials because of their optoelectronic properties, amongst others. With rising concerns ... -
The lunar Dhofar 1436 meteorite: 40Ar‐39Ar chronology and volatiles, revealed by stepwise combustion and crushing methods
Korochantseva, Ekaterina V.;; ; ; Korochantsev, Alexander V.; Anand, Mahesh; (Meteoritics & Planetary Science, 2021-03-21)
The lunar meteorite Dhofar 1436 is dominated by solar wind type noble gases. Solar argon is equilibrated with “parentless” 40Ar commonly known as lunar orphan argon. Ar‐Ar isochron analyses determined the lunar trapped ... -
The time‐resolved hard X‐ray diffraction endstation KMC‐3 XPP at BESSY II
Rössle, Matthias; Leitenberger, Wolfram; Reinhardt, Matthias; Koç, Azize;; Kwamen, Christelle; (Journal of Synchrotron Radiation, 2021-03-19)
The time‐resolved hard X‐ray diffraction endstation KMC‐3 XPP for optical pump/X‐ray probe experiments at the electron storage ring BESSY II is dedicated to investigating the structural response of thin film samples and ... -
Staircase array of inclined refractive multi‐lenses for large field of view pixel super‐resolution scanning transmission hard X‐ray microscopy
(Journal of Synchrotron Radiation, 2021-03-19)Owing to the development of X‐ray focusing optics during the past decades, synchrotron‐based X‐ray microscopy techniques allow the study of specimens with unprecedented spatial resolution, down to 10 nm, using soft and ...