Results 31 to 40 of about 928 (188)

Uranium isotopes in marine carbonates as a global ocean paleoredox proxy: A critical review [PDF]

Geochimica et Cosmochimica Acta, 2020
The protracted oxygenation of the ocean-atmosphere system is one of the most fundamental changes to the Earth system through its history. The uranium isotopic composition (²³⁸U/²³⁵U, denoted as δ²³⁸U) of marine carbonates has been developed as a proxy to quantitatively track the timing, duration, and extent of global marine redox chemistry changes ...
Zhang, Feifei, Lenton, Timothy M., del Rey, Álvaro, Romaniello, Stephen J., Chen, Xinming, Planavsky, Noah J., Clarkson, Matthew O., Dahl, Tais W., Lau, Kimberly V., Wang, Wenqian, Li, Ziheng, Zhao, Mingyu, Isson, Terry, Algeo, Thomas J., Anbar, Ariel D.   +14 more
openaire   +4 more sources

High-resolution two-dimensional quantitative analysis of phosphorus, vanadium and arsenic, and qualitative analysis of sulphide, in a freshwater sediment. [PDF]

, 2008
Recently introduced techniques that can provide two-dimensional images of solution concentrations in sediments for multiple analytes have revealed discrete sites of geochemical behaviour different from the average for that depth (microniches).
Stockdale, Anthony, Davison, William, Zhang, Hao   +2 more
core   +4 more sources

Application of elemental data in reconstruction of paleoredox conditions of the Qom Formation at Khani Abad section, southeast of Kashan [PDF]

Journal of Stratigraphy and Sedimentology Researches, 2018
Introduction The abundances of minor-elements in carbonate rocks depend on the noncarbonate materials, including detrital minerals, accessory authigenic precipitates, noncarbonate skeletal material, organic matter, phases formed during diagenesis and the
Elham Asadi Mehmandosti, Jahanbakhsh Daneshian, Nematallah Margir   +2 more
doaj   +1 more source

Past climate variations recorded in needle-like aragonites correlate with organic carbon burial efficiency as revealed by lake sediments in Croatia

Scientific Reports, 2021
The drivers of organic carbon (OC) burial efficiency are still poorly understood despite their key role in reliable projections of future climate trends.
Ivan Razum, Petra Bajo, Dea Brunović, Nikolina Ilijanić, Ozren Hasan, Ursula Röhl, Martina Šparica Miko, Slobodan Miko   +7 more
doaj   +1 more source

The effects of diagenesis on geochemical paleoredox proxies in sedimentary carbonates

Geochimica et Cosmochimica Acta, 2018
Abstract Metal and metal isotope records in carbonates have the potential to provide novel insights into ancient ocean–atmosphere redox conditions, paleoenvironmental conditions, and biogeochemical cycling. However, trace element geochemical signatures in carbonates can record either diagenetic or depositional signatures.
Ashleigh v.S. Hood, Noah J. Planavsky, Malcolm W. Wallace, Xiangli Wang   +3 more
openaire   +2 more sources

An evaluation of sedimentary molybdenum and iron as proxies for pore fluid paleoredox conditions [PDF]

American Journal of Science, 2018
Iron speciation and trace metal proxies are commonly applied together in efforts to identify anoxic settings marked by the presence of free sulfide (euxinia) or dissolved iron (ferruginous) in the water column. Here, we use a literature compilation from modern localities to provide a new empirical evaluation of coupled Fe speciation and Mo ...
Dalton S. Hardisty, Timothy W. Lyons, Natascha Riedinger, Terry T. Isson, Jeremy D. Owens, Robert C. Aller, Danny M. Rye, Noah J. Planavsky, Christopher T. Reinhard, Ben C. Gill, Andrew L. Masterson, Dan Asael, David T. Johnston   +12 more
openaire   +1 more source

Sedimentary environmental evolution in the western bohai sea since the middle pleistocene: integrating geochemical and paleontological records

Frontiers in Earth Science
Aiming to address under-utilized geochemical proxies in the Bohai Sea (BS) due to analytical complexity and diagenetic uncertainty, this study present a 300-kyr high-resolution geochemical and microfossils records from core DZQ01, and identified ...
Shuyu Wu, Shuyu Wu, Shuyu Wu, Shuyu Wu, Hongxian Chu, Hongxian Chu, Maoguo An, Yongcai Feng, Yongcai Feng, Jun Liu, Jun Liu   +10 more
doaj   +1 more source

Caracterização geoquímica e isotópica de óleos de bacias brasileiras

Geologia USP. Série Científica, 2022
Na geoquímica orgânica, a definição da origem do petróleo muitas vezes pode ser acessada por meio do estudo de suas moléculas orgânicas fósseis. Tais moléculas, os biomarcadores, permitem inferir condições ambientais da rocha geradora, possibilitando a ...
Danielle da Costa Cavalcante, Lucas Pinto Heckert Bastos, Egberto Pereira   +2 more
doaj  

Paleoenvironment and Organic Matter Accumulation Mechanism of Marine–Continental Transitional Shales: Outcrop Characterizations of the Carboniferous–Permian Strata, Ordos Basin, North China

Energies, 2021
In the Carboniferous–Permian period, several organic-rich black shales were deposited in a marine–continental transitional environment in the Linfen area on the eastern margin of the Ordos Basin.
Leifu Zhang, Qun Zhao, Sizhong Peng, Zhen Qiu, Congjun Feng, Qin Zhang, Yuman Wang, Dazhong Dong, Shangwen Zhou   +8 more
doaj   +1 more source

Relative Sea-Level Fluctuations during Rhuddanian–Aeronian Transition and Its Implication for Shale Gas Sweet Spot Forming: A Case Study of Luzhou Area in the Southern Sichuan Basin, SW China

Journal of Marine Science and Engineering, 2023
Most scholars believe that transgression events can contribute positively to organic matter enrichment and shale gas sweet spot development, while whether or not regression events are conducive to shale gas sweet spot development remains to be further ...
Tianqi Zhou, Qingzhong Zhu, Hangyi Zhu, Qun Zhao, Zhensheng Shi, Shengxian Zhao, Chenglin Zhang, Ling Qi, Shasha Sun, Ziyu Zhang, Lin Zhu   +10 more
doaj   +1 more source