Browsing Earth and Environmental Sciences by Author "Lyons, Timothy"
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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, ... -
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) ... -
Trace elements at the intersection of marine biological and geochemical evolution
Robbins, Leslie J.; Lalonde, Stefan V.; Planavsky, Noah J.; Partin, Camille A.; Reinhard, Christopher T.; Kendall, Brian; Scott, Clint; Hardisty, Dalton S.; Gill, Benjamin C.; Alessi, Daniel S.; Dupont, Christoper L.; Saito, Mak A.; Crowe, Sean A.; Poulton, Simon W.; Bekker, Andrey; Lyons, Timothy W.; Konhauser, Kurt O. (Elsevier, 2016-12-01)Life requires a wide variety of bioessential trace elements to act as structural components and reactive centers in metalloenzymes. These requirements differ between organisms and have evolved over geological time, likely ... -
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 ...