Browsing Geochemie, Mineralogie, Petrologie by Title
Now showing items 311-330 of 567
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Modelling the structural variation of quartz and germanium dioxide with temperature by means of transformed crystallographic data
(Acta Crystallographica Section B, 2021-05-27)The pseudocubic (PC) parameterization of O4 tetrahedra [Reifenberg & Thomas (2018). Acta Cryst. B74, 165–181] is applied to quartz (SiO2) and its structural analogue germanium dioxide (GeO2). In α‐quartz and GeO2, the ... -
Moisture origin and stable isotope characteristics of precipitation in southeast Siberia
(Hydrological Processes, 2019-09-02)The paper presents oxygen and hydrogen isotopes of 284 precipitation event samples systematically collected in Irkutsk, in the Baikal region (southeast Siberia), between June 2011 and April 2017. This is the first ... -
Multi-component evolution, age and plate tectonic setting of high MG lamprophyric dikes and small gabbroic intrusions on Isla Margarita (Venezuela)
(Univ. Bochum, 1997)Die Isla Margarita (Venezuela) am Südrand der Karibischen Platte besteht aus einem heterogenen Krustenkomplex aus Peridotiten, Metamorphiten, diversen Magmatiten und sedimentärem Deckgebirge. Die jüngsten Magmatite sind ... -
Multi-stage sulfide evolution of the Moran Ni sulfide ore, Kambalda, Western Australia: insights into the dynamics of ore forming processes of komatiite-hosted deposits
(Mineralium Deposita, 2021-10-05)The Moran komatiite-hosted Ni sulfide deposit at Kambalda (Australia) is one of the better preserved orebodies at Kambalda. Its geochemical signature is used to investigate the evolution of the sulfide mineralization. The ... -
Multiple Bragg reflection by a thick mosaic crystal. II. Simplified transport equation solved on a grid
(Acta Crystallographica Section A, 2020)The generalized Darwin–Hamilton equations [Wuttke (2014). Acta Cryst. A70, 429–440] describe multiple Bragg reflection from a thick, ideally imperfect crystal. These equations are simplified by making full use of energy ... -
Multi‐Band Raman Analysis of Radiation Damage in Zircon for Thermochronology: Partial Annealing and Mixed Signals
(Geochemistry, Geophysics, Geosystems, 2022-01-24)Four zircon Raman bands were previously calibrated to give consistent estimates of the accumulated self‐irradiation α‐dose in unannealed volcanic samples. Partial annealing of radiation damage produces inconsistent values ... -
Multi‐episodic formation of baddeleyite and zircon in polymetamorphic anorthosite and rutile‐bearing ilmenitite from the Chiapas Massif Complex, Mexico
(Journal of Metamorphic Geology, 2022-07-20)Massif‐type anorthosite and comagmatic associations of rutile‐bearing ilmenitite (RBI) and oxide‐apatite‐rich amphibolite (OARA) from the Chiapas Massif Complex (CMC) in southeastern Mexico display a protracted billion‐year ... -
Nano-Magnetite Aggregates in Red Soil on Low Magnetic Bedrock, Their Changes During Source-Sink Transfer, and Implications for Paleoclimate Studies
(Journal of Geophysical Research: Solid Earth, 2020)Soil and lake sediments are important paleoclimate archives often forming a source-sink setting. To better understand magnetic properties in such settings, we studied red soil on low-magnetic bedrock and subrecent sediments ... -
Nano-Powdered Calcium Carbonate Reference Materials: Significant Progress for Microanalysis?
(Geostandards and Geoanalytical Research, 2019)Homogeneity, mass fractions of about forty trace elements and Sr isotope composition of Ca carbonate reference materials (RMs) between original and nano-powdered pellets are compared. Our results using nanosecond and ... -
NanoSr – A New Carbonate Microanalytical Reference Material for In Situ Strontium Isotope Analysis
(Geostandards and Geoanalytical Research, 2019)The in situ measurement of Sr isotopes in carbonates by MC-ICP-MS is limited by the availability of suitable microanalytical reference materials (RMs), which match the samples of interest. Whereas several well-characterised ... -
Natural blue zircon from Vesuvius
(Mineralogy and Petrology, 2020-10-31)Zircon from syenitic ejecta of Vesuvius (Campania, Italy) is unusually blue, a property shared with gem zircon from Ratanakiri province (Cambodia), which turns from natural reddish-brown to blue when heated under reducing ... -
Near-Complete Local Reduction of Arctic Stratospheric Ozone by Severe Chemical Loss in Spring 2020
(Geophysical Research Letters, 2020)In the Antarctic ozone hole, ozone mixing ratios have been decreasing to extremely low values of 0.01–0.1 ppm in nearly all spring seasons since the late 1980s, corresponding to 95–99% local chemical loss. In contrast, ... -
Neon, Helium and Argon isotope systematics of the Hawaiian hotspot
(Univ. Potsdam, 2009)This study presents noble gas compositions (He, Ne, Ar, Kr, and Xe) of lavas from several Hawaiian volcanoes. Lavas from the Hawaii Scientific Drilling Project (HSDP) core, surface samples from Mauna Kea, Mauna Loa, Kilauea, ... -
New U–Pb zircon ages of Nyong Complex meta‐plutonites: Implications for the Eburnean/Trans‐Amazonian Orogeny in southwestern Cameroon (Central Africa)
(Geological Journal, 2020-10-22)New LA–ICP–MS U–Pb zircon ages from the Nyong Complex of southwestern Cameroon—a part of the West Central African Fold Belt—trace Late Mesoarchean (∼2,850 Ma), Middle Palaeoproterozoic (∼2,080 Ma), and Neoproterozoic ... -
Nitrogen and Phosphorus Control Soil Methane Uptake in Tropical Montane Forests
(Journal of Geophysical Research: Biogeosciences, 2021-08-19)Tropical forests contribute about one third to global annual CH4 uptake by soils. Understanding the factors that control the soil‐atmosphere exchange of CH4 at a large scale is a critical step to improve the CH4 flux ... -
Non-invasive detection and localization of microplastic particles in a sandy sediment by complementary neutron and X-ray tomography
(Journal of Soils and Sediments, 2021-01-27)Purpose: Microplastics have become a ubiquitous pollutant in marine, terrestrial and freshwater systems that seriously affects aquatic and terrestrial ecosystems. Common methods for analysing microplastic ... -
Non‐exchangeable stable hydrogen isotope ratios in clay minerals and soil clay fractions: A method test
(European Journal of Soil Science, 2022-08-04)Stable hydrogen isotope ratios (δ2H values) in structural hydroxyl groups of pedogenic clay minerals are inherited from the surrounding water at the time of their formation. Only non‐exchangeable H preserves the environmental ... -
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 ... -
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 ... -
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 ...