| Title | Tracking the evolution of seawater Mo isotopes through the Ediacaran-Cambrian transition |
| Authors | Ye, Yuntao Wang, Huajian Wang, Xiaomei Zhai, Lina Wu, Chaodong Canfield, Donald E. Zhang, Shuichang |
| Affiliation | China Natl Petr Corp, Key Lab Petr Geochem, Res Inst Petr Explorat & Dev, Beijing 100083, Peoples R China Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China Peking Univ, Sch Earth & Space Sci, Key Lab Orogen Belts & Crustal Evolut, Minist Educ, Beijing 100871, Peoples R China Peking Univ, Inst Oil & Gas, Beijing 100871, Peoples R China Univ Southern Denmark, Dept Biol, Nordcee, DK-5230 Odense M, Denmark |
| Keywords | DOUSHANTUO FORMATION BLACK SHALES SOUTH CHINA ATMOSPHERIC OXYGEN OCEAN OXYGENATION FERRUGINOUS CONDITIONS EUXINIC SEDIMENTS YANGTZE PLATFORM MOLYBDENUM FRACTIONATION |
| Issue Date | Nov-2020 |
| Publisher | PRECAMBRIAN RESEARCH |
| Abstract | The rapid increase in animal diversity and abundance over the Ediacaran-Cambrian boundary has been attributed to, among other parameters, pronounced Earth surface oxygenation at that time. However, whether atmospheric oxygen elevated to modern levels, or whether the extent was smaller and oxygen remained relatively muted until the late Paleozoic is currently debated. Here, we present new Mo isotope datasets of drill core material for two key black shale units (the Ediacaran Doushantuo Formation and the lower Cambrian Jiumenchong Formation), located on the Yangtze Block. These data capture a 0.7 parts per thousand isotope fractionation between sediments experiencing quantitative and non-quantitative Mo removal. By identifying this offset, we provide integrated estimates for global seawater Mo isotope compositions during the deposition of these two formations (similar to 1.2-1.4 parts per thousand and similar to 1.8-2 parts per thousand, respectively). When paired with a mass balance model, our results indicate that a large proportion of the early Cambrian ocean was bathed under oxic waters. We also discuss how recent discoveries have provided insights into the geochemical processes underpinning the oxygenation of the oceans. |
| URI | http://hdl.handle.net/20.500.11897/599492 |
| ISSN | 0301-9268 |
| DOI | 10.1016/j.precamres.2020.105929 |
| Indexed | SCI(E) |
| Appears in Collections: | 地球与空间科学学院 造山带与地壳演化教育部重点实验室 |
