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Stephen J. Romaniello
Arizona State University
46Publications
13H-index
600Citations
Publications 46
Newest
#1Zachary A. Torrano (ASU: Arizona State University)
#2Gregory A. Brennecka (WWU: University of Münster)H-Index: 15
Last.Meenakshi Wadhwa (ASU: Arizona State University)H-Index: 35
view all 7 authors...
Abstract Calcium-aluminum-rich inclusions (CAIs) are the first solids to form in the early Solar System, and they exhibit nucleosynthetic anomalies in many isotope systems. The overwhelming majority of isotopic data for CAIs is limited to inclusions from the CV chondrite Allende and a few other CV, CO, CM, and ordinary chondrites. It is therefore important to ascertain whether previously reported values for CAIs are representative of the broader CAI-forming region and to make a more rigorous ass...
#1Geoffrey J. Gilleaudeau (ASU: Arizona State University)H-Index: 6
#2Stephen J. Romaniello (ASU: Arizona State University)H-Index: 13
Last.Wang Zheng (ASU: Arizona State University)H-Index: 7
view all 10 authors...
Abstract Reconstructing Earth's oxygenation history is key to deciphering environmental controls on early biospheric evolution. During the mid-Proterozoic Eon, low (but potentially variable) atmospheric p O 2 led to highly heterogeneous marine redox conditions, with most studies indicating a relatively shallow depth of oxygen penetration. The relative proportion of oxic, anoxic and iron-rich (ferruginous), and anoxic and sulfide-rich (euxinic) conditions on the global seafloor is difficult to qu...
#1Chadlin M. Ostrander (ASU: Arizona State University)H-Index: 2
#2Swapan K. Sahoo (UNLV: University of Nevada, Las Vegas)H-Index: 3
Last.Stephen J. Romaniello (ASU: Arizona State University)H-Index: 13
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Abstract 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) isotope excursions (to as low as δ 98 Mo NIST+0.25 = -2.24 ± 0.10‰; 2SD) in shales from four separate sites in South China (Rongxi, Taoying, Wuhe, and Yuanjia) that preserve the Doushantuo Formation. The negative δ 98 Mo excursions appear coincident with previously discovered and...
#1Feifei ZhangH-Index: 6
#2Shuhai Xiao (VT: Virginia Tech)H-Index: 51
Last.Timothy M. Lenton (University of Exeter)H-Index: 53
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#1Chadlin M. Ostrander (ASU: Arizona State University)H-Index: 2
#2Sune G. Nielsen (WHOI: Woods Hole Oceanographic Institution)H-Index: 23
Last.Ariel D. Anbar (ASU: Arizona State University)H-Index: 56
view all 7 authors...
#1Aleisha C. Johnson (ASU: Arizona State University)H-Index: 1
#2Stephen J. Romaniello (ASU: Arizona State University)H-Index: 13
Last.Ariel D. AnbarH-Index: 56
view all 9 authors...
Abstract Constraining the rate at which sulfide minerals undergo oxidative weathering at low atmospheric O 2 is crucial for understanding the evolution of the Archean and Proterozoic biosphere when O 2 was a trace atmospheric gas. However, recent studies attempting to constrain sulfide oxidation rates, atmospheric O 2 sinks, and trace metal delivery to seawater under Archean conditions are limited by the need to extrapolate from experimental pyrite oxidation kinetics determined at much higher O ...
#1Chadlin M. Ostrander (ASU: Arizona State University)H-Index: 2
#2Sune G. Nielsen (WHOI: Woods Hole Oceanographic Institution)H-Index: 23
Last.Ariel D. Anbar (ASU: Arizona State University)H-Index: 56
view all 7 authors...
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 oxygenation remains poorly constrained. Here we present thallium and molybdenum isotope compositions for anoxic organic-rich shales of the 2.5-billion-year-old Mount McRae Shale from Western Australia, which previously yielded geochemical evidence of a transient oxygenation event...
#1David A. White (UNM: University of New Mexico)H-Index: 1
#2Maya Elrick (UNM: University of New Mexico)H-Index: 19
Last.Feifei Zhang (ASU: Arizona State University)H-Index: 6
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Abstract The Late Devonian extinction ranks as one of the ‘big five’ Phanerozoic extinctions affecting up to 80% of marine species and is characterized by two major extinction events that are separated by δ 238 U) across a ∼7 My interval of well-dated Upper Devonian marine limestones from the Devil's Gate Formation in Nevada, USA. The measured δ 238 U curve shows no co-variation with local sediment-derived redox trends, water-depth dependent facies changes, redox-sensitive metals, TOC, or diagno...
#1Xinming Chen (ASU: Arizona State University)H-Index: 3
#2Stephen J. Romaniello (ASU: Arizona State University)H-Index: 13
Last.Ariel D. Anbar (ASU: Arizona State University)H-Index: 56
view all 5 authors...
Abstract Determining whether U isotopes are fractionated during incorporation into biogenic carbonates could help to refine the application of 238 U/ 235 U in CaCO 3 as a robust paleoredox proxy. Recent laboratory experiments have demonstrated that heavy uranium (U) isotopes were preferentially incorporated into abiotic aragonite, with an isotope fractionation of ∼0.10‰ ( 238 U/ 235 U). In contrast, no detectable U isotope fractionation has been observed in most natural primary biogenic carbonat...
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