Auflistung Geochemie, Mineralogie, Petrologie nach Titel
Anzeige der Dokumente 258-277 von 565
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Key parameters of volcanic tuffs used as building stone: a statistical approach
(Environmental Earth Sciences, 2021-12-08)Volcanic tuffs naturally show a strong heterogeneity in their petrography and petrophysical properties. The arrangement of the components in tuffs can create a very wide spectrum of porosities and fabrics, which in turn ... -
Kinematics of Crystal Growth in Single‐Seal Syntaxial Veins in Limestone ‐ A Phase‐Field Study
(Journal of Geophysical Research: Solid Earth, 2021-09-28)Building on recent developments in phase‐field modeling of structural diagenesis, we present an analysis of single‐seal syntaxial calcite vein microstructure in a variety of limestones. We focus on the effects of fracture ... -
Laboratory and field investigations on freeze and gravity core sampling and assessment of coring disturbances with implications on gas bubble characterization†
(Limnology and Oceanography: Methods, 2019)The quantification of greenhouse gas emissions from aquatic ecosystems requires knowledge about the spatial and temporal dynamics of free gas in sediments. Freezing the sediment in situ offers a promising method for obtaining ... -
Laboratory Assessment of the Impact of Chemical Oxidation, Mineral Dissolution, and Heating on the Nitrogen Isotopic Composition of Fossil‐Bound Organic Matter
(Geochemistry, Geophysics, Geosystems, 2022-08-19)Fossil‐bound organic material holds great potential for the reconstruction of past changes in nitrogen (N) cycling. Here, with a series of laboratory experiments, we assess the potential effect of oxidative degradation, ... -
Laboratory testing and numerical simulation of properties and thermal-induced cracking of Eibenstock granite at elevated temperatures
(Acta Geotechnica, 2020-02-11)The knowledge about thermo-mechanical properties of granite is still limited to some extent. Individual measurements are necessary to obtain reliable properties for specific granite types. A reliable numerical model of ... -
Laboruntersuchungen zur Freisetzung von Unat aus einem Gestein unter oxischen naturnahen Bedingungen
(Grundwasser, 2005)The effects of carbonate concentration and the presence of iron hydroxide phases on uranium release into the environment were investigated under oxic conditions and in the pH range from 6 to 9. For this purpose not-shaken ... -
Laser ablation ICP-MS in paleoceanography - a regional study on the benthic foraminifer Oridorsalis umbonatus in the Benguela upwelling area off Namibia
(Univ. Bremen, 2008)The different benthic foraminiferal species (epibenthic as well as endobenthic) colonize wide areas of the ocean floor and are widely used for paleoceanographic reconstructions. To improve these reconstructions, it is an ... -
Last Glacial central Mediterranean hydrology inferred from Lake Trasimeno’s (Italy) calcium carbonate geochemistry
(Boreas, 2021-09-02)There is still a paucity of hydrological data explaining the relationship between (rapid, millennial‐scale) climate forcing and Mediterranean rainfall since the Last Glacial. We show that distinct lake‐level fluctuations ... -
Late Holocene to Recent aragonite-cemented transgressive lag deposits in the Abu Dhabi lagoon and intertidal sabkha
(Sedimentology, 2020)Modern cemented intervals (beachrock, firmgrounds to hardgrounds and concretionary layers) form in the lagoon and intertidal sabkha of Abu Dhabi. Seafloor lithification actively occurs in open, current-swept channels in ... -
Lateral variations in the Unit 7–8 boundary zone of the Rum Eastern Layered Intrusion, NW Scotland: implications for the origin and timing of Cr-spinel seam formation
(Contributions to Mineralogy and Petrology, 2020-09-02)The Rum Layered Suite, NW Scotland, hosts Cr-spinel seams at the bases of peridotite–troctolite macro-rhythmic units in the eastern portion of the intrusion. Here, we present detailed field observations together with ... -
Latest Carboniferous to early Permian volcano-stratigraphic evolution in Central Europe: U–Pb CA–ID–TIMS ages of volcanic rocks in the Thuringian Forest Basin (Germany)
(International Journal of Earth Sciences, 2020-11-23)Mainly acidic Stephanian to early Permian volcanic rocks and intercalated sediments accumulated in the Thuringian Forest Basin (TFB) in central Germany to a total thickness of ca. 2000 m. This basin offers a wide range of ... -
Layer groups: Brillouin‐zone and crystallographic databases on the Bilbao Crystallographic Server
(Acta Crystallographica Section A, 2021-09-24)The section of the Bilbao Crystallographic Server (https://www.cryst.ehu.es/) dedicated to subperiodic groups contains crystallographic and Brillouin‐zone databases for the layer groups. The crystallographic databases ... -
Li-Co–Ni-Mn-(REE) veins of the Western Erzgebirge, Germany—a potential source of battery raw materials
(Mineralium Deposita, 2021-06-25)Situated in the western Erzgebirge metallogenetic province (Vogtland, Germany), the Eichigt prospect is associated with several quartz-Mn-Fe-oxyhydroxide veins that are exposed at surface. Bulk-rock geochemical assays of ... -
Limited angle tomography for transmission X-ray microscopy using deep learning
(Journal of Synchrotron Radiation, 2020)In transmission X-ray microscopy (TXM) systems, the rotation of a scanned sample might be restricted to a limited angular range to avoid collision with other system parts or high attenuation at certain tilting angles. Image ... -
Linking the Dissolved and Particulate Domain of Organic Carbon in Inland Waters
(Journal of Geophysical Research: Biogeosciences, 2021-05-11)Organic carbon (OC) in inland waters is found in either dissolved or particulate states, each contributing differently to carbon cycling through state‐specific forms of transport, processing, and mineralization. Degradation ... -
Lithium and Sr isotopic composition of salar deposits in the Central Andes across space and time: the Salar de Pozuelos, Argentina
(Mineralium Deposita, 2021-07-07)The Central Andes of South America host the largest known lithium resources in a confined area, but the primary lithium sources of the salar deposits and the mobilisation process of lithium are still a matter of speculation. ... -
Long‐Period Astronomical Forcing of Westerlies' Strength in Central Asia During Miocene Climate Cooling
(Paleoceanography and Paleoclimatology, 2019-11-29)The continental expression of global cooling during the Miocene Climate Transition in Central Asia is poorly documented, as the tectonically active setting complicates the correlation of Neogene regional and global climatic ... -
Long‐term intercomparison of two pCO2 instruments based on ship‐of‐opportunity measurements in a dynamic shelf sea environment
(Limnology and Oceanography: Methods, 2020-12-28)The partial pressure of carbon dioxide (pCO2) in surface seawater is an important biogeochemical variable because, together with the pCO2 in the atmosphere, it determines the direction of air–sea carbon dioxide exchange. ... -
Long‐Term Nitrate Trajectories Vary by Season in Western European Catchments
(Global Biogeochemical Cycles, 2021-09-12)Human alteration of nutrient cycles has caused persistent and widespread degradation of water quality around the globe. In many regions, including Western Europe, elevated nitrate (NO3−) concentration in surface waters ... -
Lösungskinetik von Gips und Anhydrit
(Univ. Bremen, 2002)The dissolution kinetics of gypsum and anhydrite have been measured under various conditions. For gypsum an almost linear rate equation R=ks1(1-c/ceq)n1 is valid, where R is the surface rate, n1 1 is the kinetics order, ...