Auflistung Geochemie, Mineralogie, Petrologie nach Titel
Anzeige der Dokumente 209-228 von 567
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High‐resolution facies analysis of a coastal sabkha in the eastern Gulf of Salwa (Qatar): A spatio‐temporal reconstruction
(Sedimentology, 2021-10-12)Abstract Sabkhas are key landforms along the southern coast of the Arabian Gulf and represent modern analogues for depositional and diagenetic processes controlling properties and quality of ancient hydrocarbon‐bearing ... -
High‐resolution XEOL spectroscopy setup at the X‐ray absorption spectroscopy beamline P65 of PETRA III
(Journal of Synchrotron Radiation, 2022-08-11)A newly designed setup to perform steady‐state X‐ray excited optical luminescence (XEOL) spectroscopy and simultaneous XEOL and X‐ray absorption spectroscopy characterization at beamline P65 of PETRA III is described. The ... -
High‐temperature treatments of niobium under high vacuum, dilute air‐ and nitrogen‐atmospheres as investigated by in situ X‐ray absorption spectroscopy
(Journal of Synchrotron Radiation, 2020-12-18)Niobium metal foils were heat‐treated at 900°C under different conditions and in situ investigated with time‐resolved X‐ray absorption fine‐structure (EXAFS and XANES) measurements. The present study aims to mimic the ... -
Hochtemperatur-Lösungskalorimetrie und Leistungsdifferenzkalorimetrie zur thermodynamischen Charakterisierung von Mineralien
(Univ. Bochum, 2000)Kalorimetrische Untersuchungen sind ein unverzichtbares Instrument bei der Bestimmung der thermodynamischen Eigenschaften von Mineralen, um deren Gleichgewichts- und Reaktionsbeziehungen vorhersagbar zu machen.Im Rahmen ... -
How do secondary iron enrichments form within basaltic eucrites? An experimental approach
(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 ... -
How Important is Denitrification in Riparian Zones? Combining End-Member Mixing and Isotope Modeling to Quantify Nitrate Removal from Riparian Groundwater
(Water Resources Research, 2020)Riparian zones are important buffer zones for streams as they are hotspots of nitrate transformation and removal in agricultural catchments. However, mixing of water from different sources and various transformation processes ... -
HTD2: a single‐crystal X‐ray diffractometer for combined high‐pressure/low‐temperature experiments at laboratory scale
(Journal of Applied Crystallography, 2022-09-29)High‐pressure (HP) X‐ray diffraction experiments at low temperature (LT) require dedicated instruments as well as non‐standard sample environments and measuring strategies. This is especially true when helium cryogenic ... -
Hydrochemistry and environmental isotopes (18O, 2H, 3H, 3He/4He) of groundwater and floodwater in the great area of Hurghada, Eastern Desert of Egypt
(Environmental Earth Sciences, 2021-05-28)Porous and fractured aquifers exist in the area of Hurghada, Eastern Desert of Egypt, whose recharge processes through the common flash floods are not identified. Hydrochemical parameters, stable isotopes 18O, ... -
Hydrogen Diffusion in Clinopyroxene at Low Temperatures (195°C–400°C) and Consequences for Subsurface Processes
(Geochemistry, Geophysics, Geosystems, 2022-12-12)Studying diffusion of hydrogen in nominally anhydrous minerals, like clinopyroxene, at low temperatures is a challenging task due to experimental and analytical difficulties. In this study, to overcome these problems we ... -
Hydrothermalsynthesen von PbS-ZnS und FeS-ZnS
(Aachen, Technische Hochschule, Fakultät für Bergbau und Hüttenwesen, 1963)Der Anlaß für die in dieser Arbeit unternommenen hydrothermalsynthetischen Versuche war die auf sulfidischen Bleizinkerzlagerstätten allgemein beobachtete Erscheinung, daß Zinkblende vor Bleiglanz auskristallisiert. Die ... -
Ice Age‐Holocene Similarity of Foraminifera‐Bound Nitrogen Isotope Ratios in the Eastern Equatorial Pacific
(Paleoceanography and Paleoclimatology, 2021-05-19)Bulk sediment δ15N records from the eastern tropical Pacific (ETP) extending back to the last ice age most often show low glacial δ15N, then a deglacial δ15N maximum, followed by a gradual decline to a late Holocene δ15N ... -
Identifying Dominant Processes in Time and Space: Time‐Varying Spatial Sensitivity Analysis for a Grid‐Based Nitrate Model
(Water Resources Research, 2022-08-04)Distributed models have been increasingly applied at finer spatiotemporal resolution. However, most diagnostic analyses aggregate performance measures in space or time, which might bias subsequent inferences. Accordingly, ... -
Immiscible silicate liquids: K and Fe distribution as a test for chemical equilibrium and insight into the kinetics of magma unmixing
(Contributions to Mineralogy and Petrology, 2021-05-24)Silicate liquid immiscibility leading to formation of mixtures of distinct iron-rich and silica-rich liquids is common in basaltic and andesitic magmas at advanced stages of magma evolution. Experimental modeling of the ... -
Impact Experiment on Gneiss: The Effects of Foliation on Cratering Process
(Journal of Geophysical Research: Solid Earth, 2019)Two impact experiments were carried out on blocks of Maggia gneiss to assess the influence of mechanical target anisotropies on the cratering process. The experiments were done within the framework of Multidisciplinary ... -
Impact of different chloride salts and their concentrations on nitrification and trace gas emissions from a sandy soil under a controlled environment
(Soil Use and Management, 2021-03-10)Potassium chloride (KCl) and magnesium chloride (MgCl2) can be used to reduce carbon dioxide (CO2) and nitrous oxide (N2O) emissions, but their efficacy can be strongly affected by their Cl− concentration. This study aimed ... -
Impact of increasing carbon dioxide on dinitrogen and carbon fixation rates under oligotrophic conditions and simulated upwelling
(Limnology and Oceanography, 2021-06-04)Dinitrogen (N2) fixation is a major source of bioavailable nitrogen to oligotrophic ocean communities. Yet, we have limited understanding how ongoing climate change could alter N2 fixation. Most of our understanding is ... -
Impact of sedimentation history for As distribution in Late Pleistocene-Holocene sediments in the Hetao Basin, China
(Journal of Soils and Sediments, 2020-07-01)Purpose: To understand the impact of geochemical sedimentation history for arsenic (As) distribution in the sediment profiles of the Hetao Basin, we (1) evaluated sediments provenance and variations of weathering ... -
Impacts of Drying and Rewetting on the Radiocarbon Signature of Respired CO2 and Implications for Incubating Archived Soils
(Journal of Geophysical Research: Biogeosciences, 2021-09-14)The radiocarbon signature of respired CO2 (∆14C‐CO2) measured in laboratory soil incubations integrates contributions from soil carbon pools with a wide range of ages, making it a powerful model constraint. Incubating ... -
Implications for sedimentary transport processes in southwestern Africa: a combined zircon morphology and age study including extensive geochronology databases
(International Journal of Earth Sciences, 2021-12-17)Extensive morphological and age studies on more than 4600 detrital zircon grains recovered from modern sands of Namibia reveal complex mechanisms of sediment transport. These data are further supplemented by a zircon age ... -
Implications of Reactions Between SO2 and Basaltic Glasses for the Mineralogy of Planetary Crusts
(Journal of Geophysical Research: Planets, 2019)Basalts are ubiquitous in volcanic systems on several planetary bodies, including the Earth, Mars, Venus, and Jupiter's moon Io, and are commonly associated with sulfur dioxide (SO2) degassing. We present the results of ...