Browsing Earth and Environmental Sciences by Author "Anbar, Ariel"
Now showing items 1-8 of 8
-
An expanded shale δ98Mo record permits recurrent shallow marine oxygenation during the Neoarchean
Ostrander, Chadlin; Kendall, Brian; Olson, Stephanie; Lyons, Timothy; Gordon, Gwyneth; Romaniello, Stephen; Zheng, Wang; Reinhard, Christopher; Roy, Moutusi; Anbar, Ariel (Elsevier, 2020-01-20)Multiple attempts have been made using the ancient shale record to track the molybdenum isotope composition (δ98Mo) of seawater during the final two-hundred million years of the Archean Eon (2.7 to 2.5 billion-years-ago, ... -
Extensive marine anoxia during the terminal Ediacaran Period
Zhang, Feifei; Xiao, Shuhai; Kendall, Brian; Romaniello, Stephen J.; Cui, Huan; Meyer, Mike; Gilleaudeau, Geoffrey J.; Kaufman, Alan J.; Anbar, Ariel (American Association for the Advancement of Science, 2018-06-20)The terminal Ediacaran Period witnessed the decline of the Ediacara biota (which may have included many stemgroup animals). To test whether oceanic anoxia might have played a role in this evolutionary event, we measured U ... -
Fully oxygenated water columns over continental shelves before the Great Oxidation Event
Ostrander, Chadlin; Nielsen, Sune; Owens, Jeremy; Kendall, Brian; Gordon, Gwyneth; Romaniello, Stephen; Anbar, Ariel (Nature, 2019-02-25)Late Archaean sedimentary rocks contain compelling geochemical evidence for episodic accumulation of dissolved oxygen in the oceans along continental margins before the Great Oxidation Event. However, the extent of this ... -
Good Golly, Why Moly? THE STABLE ISOTOPE GEOCHEMISTRY OF MOLYBDENUM
Kendall, Brian; Dahl, Tais W.; Anbar, Ariel (Mineralogical Society of America, 2017-01-01)No abstract available. -
A Model for the Oceanic Mass Balance of Rhenium and Implications for the Extent of Proterozoic Ocean Anoxia
Sheen, Alex I.; Kendall, Brian; Reinhard, Christopher T.; Creaser, Robert; Lyons, Timothy W.; Bekker, Andrey; Poulton, Simon W.; Anbar, Ariel (Elsevier, 2018-04-15)Emerging geochemical evidence suggests that the atmosphere-ocean system underwent a significant decrease in O2 content following the Great Oxidation Event (GOE), leading to a mid-Proterozoic ocean (ca. 2.0–0.8 Ga) with ... -
Multiple negative molybdenum isotope excursions in the Doushantuo Formation (South China) fingerprint complex redox-related processes in the Ediacaran Nanhua Basin
Ostrander, Chadlin; Swapan, Sahoo; Kendall, Brian; Jiang, Ganqing; Planavsky, Noah; Lyons, Timothy; Nielsen, Sune; Owens, Jeremy; Gordon, Gwyneth; Romaniello, Stephen; Anbar, Ariel (Elsevier, 2019-09-15)The Ediacaran Doushantuo Formation offers one of the most complete and extensively studied records of end- Neoproterozoic biotic and environmental change. Here, we report multiple coeval negative molybdenum (Mo) ... -
Transient episodes of mild environmental oxygenation and oxidative continental weathering during the late Archean
Kendall, Brian; Creaser, Robert; Reinhard, Christopher T.; Lyons, Timothy W.; Anbar, Ariel (American Association for the Advancement of Science, 2015-11-20)It is not known whether environmental O2 levels increased in a linear fashion or fluctuated dynamically between the evolution of oxygenic photosynthesis and the later Great Oxidation Event. New rhenium-osmium isotope data ... -
Uranium and molybdenum isotope evidence for an episode of widespread ocean oxygenation during the late Ediacaran Period
Kendall, Brian; Komiya, Tsuyoshi; Lyons, Timothy W.; Bates, Steve M.; Gordon, Gwyneth W.; Romaniello, Stephen J.; Jiang, Ganqing; Creaser, Robert; Xiao, Shuhai; McFadden, Kathleen; Sawaki, Yusuke; Tahata, Miyuki; Shu, Degan; Han, Jian; Li, Yong; Chu, Xuelei; Anbar, Ariel (Elsevier, 2015-05-01)To improve estimates of the extent of ocean oxygenation during the late Ediacaran Period, we measured the U and Mo isotope compositions of euxinic (anoxic and sulfidic) organic-rich mudrocks (ORM) of Member IV, upper ...