Browsing Earth and Environmental Sciences by Author "Kendall, Brian"
Now showing items 1-16 of 16
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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, ... -
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 ... -
Genesis of a giant Paleoproterozoic strata-bound magnesite deposit: Constraints from Mg isotopes
Dong, Aiguo; Zhu, Xiang-kun; Li, Shi-Zhen; Kendall, Brian; Wang, Yue; Gao, Zhaofu (Elsevier, 2016-08-01)Giant strata-bound magnesite deposits are absent in modern and most Phanerozoic sedimentary environments but occur predominantly in Precambrian strata. These deposits may have formed directly through precipitation of evolved ... -
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. -
Inverse correlation between the molybdenum and uranium isotope compositions of Upper Devonian black shales caused by changes in local depositional conditions rather than global ocean redox variations
Kendall, Brian; Wang, Jieying; Zheng, Wang; Romaniello, Stephen; Over, Jeffrey; Bennett, Yvonne; Xing, Liyan; Kunert, Alexandra; Boyes, Cameron; Liu, Jian (Elsevier, 2020-10-15)Coupled Mo-U isotope data from the Upper Devonian Kettle Point Formation (Ontario, Canada) provide a cautionary tale regarding interpretation of global ocean redox conditions using data from euxinic black shales. In the ... -
Marine redox conditions during deposition of Late Ordovician and Early Silurian organic-rich mudrocks in the Siljan ring district, central Sweden
Lu, Xinze; Kendall, Brian; Stein, Holly J.; Li, Chao; Hannah, Judith L.; Gordon, Gwyneth W.; Ebbestad, Jan Ove R. (Elsevier, 2017-05-10)The Late Ordovician Period witnessed the second largest mass extinction in the Phanerozoic Eon and the Hirnantian glaciation. To infer ocean redox conditions across the Ordovician-Silurian transition, we measured the U (as ... -
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 ... -
A multi-isotope approach towards constraining the origin of large-scale Paleoproterozoic B-(Fe) mineralization in NE China
Dong, Aiguo; Zhu, Xiang-kun; Li, Zhihong; Kendall, Brian; Li, Shi-Zhen; Wang, Yue; Tang, Chao (Elsevier, 2017-05-01)Borate ore deposits occur predominantly in Phanerozoic evaporative sedimentary environments but are scarce in Precambrian strata. However, massive B- and Mg-rich borate deposits are abundant in the Paleoproterozoic strata ... -
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) ... -
Redox conditions across the Cambrian–Ordovician boundary: Elemental and isotopic signatures retained in the GSSP carbonates
Azmy, Karem; Kendall, Brian; Brand, Uwe; Stouge, Svend; Gordon, Gwyneth W. (Elsevier, 2015-12-15)Lime mudstone samples (rhythmites) were collected at high resolution from outcrops of the Cambrian–Ordovician GSSP boundary section at Green Point (western Newfoundland, Canada). The sequence (~45 mthick) consists of slope ... -
Temporal record of osmium concentrations and 187Os/188Os in organic-rich mudrocks: Implications for the osmium geochemical cycle and the use of osmium as a paleoceanographic tracer
Lu, Xinze; Kendall, Brian; Stein, Holly J.; Hannah, Judith L. (Elsevier, 2017-11-01)We present a compilation of 192Os concentrations (representing non-radiogenic Os) and initial 187Os/188Os isotope ratios from organic-rich mudrocks (ORM) to explore the evolution of the Os geochemical cycle during the ... -
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 ... -
Uranium isotope compositions of mid-Proterozoic black shales: Evidence for an episode of increased ocean oxygenation at 1.36Ga and evaluation of the effect of post-depositional hydrothermal fluid flow
Yang, Shuai; Kendall, Brian; Lu, Xinze; Zhang, Feifei; Zheng, Wang (Elsevier, 2017-09-01)We report U isotope data for marine black shales of the early Mesoproterozoic Velkerri Formation (Roper Group) and late Paleoproterozoic Wollogorang Formation (Tawallah Group) from the McArthur Basin, Northern Australia. ...