Results 21 to 30 of about 42,866 (280)

Stable carbon and radiocarbon isotope compositions of particle size fractions to determine origins of sedimentary organic matter in an estuary [PDF]

, 2002
Stable and radioactive carbon isotopic compositions of particle size fractions of a surface sediment from the Ems-Dollard estuary vary considerably with particle size. The organic material in the fine fractions (
Megens, L.,, de Leeuw, JW, van der Plicht, J, Smedes, F, Smedes, F.,, Megens, L, Plicht, J. van der,, Leeuw, J.W. de,   +7 more
core   +1 more source

Copper and its Isotopes in Organic-Rich Sediments: From the Modern Peru Margin to Archean Shales

Geosciences, 2019
The cycling of copper (Cu) and its isotopes in the modern ocean is controlled by the interplay of biology, redox settings, and organic complexation. To help build a robust understanding of Cu cycling in the modern ocean and investigate the potential ...
Emily R. Ciscato, Tomaso R. R. Bontognali, Simon W. Poulton, Derek Vance   +3 more
doaj   +1 more source

Oxygen isotope ecology of recent planktic foraminifera at the central Walvis Ridge (SE Atlantic) [PDF]

, 2005
Above the Walvis Ridge, in the SE Atlantic Ocean, we collected living plantkic foraminifera from the upper water column using depth stratified plantkon tows. The oxygen isotope composition (
Kroon, Dirk, Dick Kroon, Brummer, G.J.A., Neven Lončarić, Brummer, G. J. A., Kroon, D., Peeters, F. J. C., Peeters, F.J.C., Geert‐Jan A. Brummer, Loncaric, N., Frank J. C. Peeters   +10 more
core   +1 more source

Impact of chemical treatments on the molecular and stable carbon isotopic composition of sporomorphs [PDF]

Biogeosciences
The stable carbon isotope composition (δ13C) of plants and algae is influenced by environmental factors, such as pCO2, water availability, and altitude.
Y. F. Bats, K. G. J. Nierop, A. Stuart-Lee, J. Frieling, J. Frieling, L. van Roij, G.-J. Reichart, G.-J. Reichart, A. Sluijs   +8 more
doaj   +1 more source

What happened to the Early Precambrian granulite complexes of the Bug region (Ukrainian shield) and the Limpopo belt (South Africa) and how to stratify them? A tectonist’s view

Геофизический журнал, 2022
The author reviews two alternative approaches (stratigenic-metamorphogenic and deformation-metamorphogenic) to the geology and mapping of the Earth’s oldest crust rocks that were metamorphized in РТ-conditions of the granulite facies, on the examples of
O.B. Gintov
doaj   +1 more source

Provenance of the Lower Triassic Clastic Rocks in the Southwestern Margin of the South China Craton and Its Implications for the Subduction Polarity of the Paleo-Tethyan Ocean

Frontiers in Earth Science, 2022
The southwestern margin of the South China Craton preserves a Late Permian to Early Triassic sedimentary succession, the provenance of which helps to constrain the magmatic history and tectonic evolution of the Paleo-Tethyan Orogen.
Chao Han, Chao Han, Hu Huang, Hu Huang, Chenchen Yang, Chenchen Yang, Linxi Wang, Linxi Wang, Hongwei Luo, Hongwei Luo   +9 more
doaj   +1 more source

Detrital zircon Hf isotopic compositions indicate a northern Caledonian connection for the Alexander terrane [PDF]

Lithosphere, 2013
Various plate reconstructions predict that the Alexander terrane, a Neoproterozoic-Jurassic crustal fragment now located in the North American Cordillera, evolved in proximity to the northern Appal ...
Luke P. Beranek, Cees R. van Staal, William C. McClelland, Steve Israel, Mitch G. Mihalynuk   +4 more
openaire   +1 more source

Ketazine‐Linked Covalent Organic Framework for Metal‐Free Electrocatalytic Nitrate‐to‐Ammonia Conversion

Angewandte Chemie, EarlyView.
A metal‐free fluorinated ketazine‐linked COF is introduced as an efficient electrocatalyst for nitrate reduction to ammonia under neutral conditions. Fluorine substitution enhances π–π stacking and crystallinity, enabling a Faradaic efficiency of 59.9% and an NH3 yield rate of 1639.9 µmol h−1 mgCOF−1 at −0.9 V versus RHE. This establishes an unexplored
Islam E. Khalil, Ashadul Adalder, Badr Elkamash, Narad Barman, Darosch Asgari, Luoxing Xiang, Warisha Tahir, Franziska Hess, Ranjit Thapa, Adisak Boonchun, Uttam Kumar Ghorai, Prasenjit Das, Arne Thomas   +12 more
wiley   +2 more sources

Hf isotope composition of zircons and implication for the petrogenesis of Yajiangqiao granite, Hunan Province, China

Chinese Science Bulletin, 2003
In the peralumineous granite of Yajiangqiao zircon population can be divided into two groups (i.e. Zircon I and Zircon II), which were formed in magmatic chamber and in emplacement place, respectively. The Hf isotope compositions of two stages of zircon show that the host magma was essentially derived from crustal material by melting.
Xiang Wang, W. L. Griffin, Zhicheng Wang, Xinmin Zhou   +3 more
openaire   +2 more sources

The isotopic composition of methane in the stratosphere : high-altitude balloon sample measurements [PDF]

, 2011
The isotopic composition of stratospheric methane has been determined on a large suite of air samples from stratospheric balloon flights covering subtropical to polar latitudes and a time period of 16 yr.
Brass, Marc, Engel, A., Röckmann, Thomas, A. Engel, Borchers, Reinhard, T. Röckmann, M. Brass, Brass, M., Engel, Andreas, Röckmann, T., Borchers, R., R. Borchers   +11 more
core   +1 more source