TY - JOUR
T1 - Global and local drivers of the Ediacaran Shuram carbon isotope excursion
AU - Busch, James F.
AU - Hodgin, Eben B.
AU - Ahm, Anne Sofie C.
AU - Husson, Jon M.
AU - Macdonald, Francis A.
AU - Bergmann, Kristin D.
AU - Higgins, John A.
AU - Strauss, Justin V.
N1 - Funding Information:
We are grateful to the Tr'ondëk Hwëch'in community for granting us permission to work in the Ogilvie and Wernecke Mountains; and to Peru's Servicio Nacional de Áreas Naturales Protegidas por el Estado for granting permission to work in the Punta San Juan Reserve. KDB thanks Petroleum Development Oman for field support in Oman and Maggie Osburn for her contributions to field work in Oman. This project was supported by: National Science Foundation (NSF) grants EAR-1654131 and EAR-2021176 awarded to JVS; NSF grant EAR-1916698 awarded to FAM; Simons Foundation grant SCOL 611878 awarded to ASCA, National Geographic Society Grant EC-393R-18 awarded to JFB; a American Philosophical Society Lewis and Clark grant awarded to JFB; a Geological Society of America (GSA) graduate student research grant awarded to JFB; and field support from the Yukon Geological Survey. We thank David Moynihan, Erik Sperling, and Tom Boag for field assistance and thank Stefania Gili, Jack Murphy, and Nic Slater for assistance in the lab. We thank Boswell Wing for editorial handling of our manuscript. Finally, this contribution benefited from thoughtful reviews by Cedric Hagen and an anonymous reviewer.
Funding Information:
We are grateful to the Tr'ondëk Hwëch'in community for granting us permission to work in the Ogilvie and Wernecke Mountains; and to Peru's Servicio Nacional de Áreas Naturales Protegidas por el Estado for granting permission to work in the Punta San Juan Reserve. KDB thanks Petroleum Development Oman for field support in Oman and Maggie Osburn for her contributions to field work in Oman. This project was supported by: National Science Foundation (NSF) grants EAR-1654131 and EAR-2021176 awarded to JVS; NSF grant EAR-1916698 awarded to FAM; Simons Foundation grant SCOL 611878 awarded to ASCA, National Geographic Society Grant EC-393R-18 awarded to JFB; a American Philosophical Society Lewis and Clark grant awarded to JFB; a Geological Society of America (GSA) graduate student research grant awarded to JFB; and field support from the Yukon Geological Survey. We thank David Moynihan, Erik Sperling, and Tom Boag for field assistance and thank Stefania Gili, Jack Murphy, and Nic Slater for assistance in the lab. We thank Boswell Wing for editorial handling of our manuscript. Finally, this contribution benefited from thoughtful reviews by Cedric Hagen and an anonymous reviewer.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/2/1
Y1 - 2022/2/1
N2 - The Ediacaran Shuram carbon isotope excursion (CIE) follows the regional Gaskiers glaciation and occurs before the appearance of macroscopic animal fossils. Previous interpretations for the Shuram CIE have proposed global perturbations to Earth's carbon cycle accompanied by significant climatic and environmental change. These studies assume that carbonate carbon isotopes through the Shuram CIE record the composition of dissolved inorganic carbon in seawater. Through a compilation of new geochemical, sedimentological, and stratigraphic data from five localities on four separate paleocontinents, we find that all of the analyzed Shuram CIE successions share general similarities including a common transgressive-regressive sequence that is coincident with similar shifts in a host of geochemical proxies (δ13C, δ18O, δ44/40Ca, Sr/Ca, Mn/Sr, U/Ca). Despite these broad similarities between sections, there are important differences in the proxies between water depths that may be linked to changes in carbonate diagenesis. Specifically, we find the excursion's magnitude is largest in slope environments where diagenesis is sediment-buffered and smaller in shallow-water settings dominated by fluid-buffered diagenesis. The transgression that accompanied the Shuram CIE is consistent in amplitude (∼10-100s m) and duration (>1 My) with eustatic fluctuations driven by plate reorganization. These coupled geochemical and stratigraphic observations argue against meteoric and burial diagenesis as drivers for the excursion; instead, they are best explained by global changes to the locus and intensity of photosynthetic primary productivity in shallow-water environments and do not necessarily require large changes in global climate or marine redox.
AB - The Ediacaran Shuram carbon isotope excursion (CIE) follows the regional Gaskiers glaciation and occurs before the appearance of macroscopic animal fossils. Previous interpretations for the Shuram CIE have proposed global perturbations to Earth's carbon cycle accompanied by significant climatic and environmental change. These studies assume that carbonate carbon isotopes through the Shuram CIE record the composition of dissolved inorganic carbon in seawater. Through a compilation of new geochemical, sedimentological, and stratigraphic data from five localities on four separate paleocontinents, we find that all of the analyzed Shuram CIE successions share general similarities including a common transgressive-regressive sequence that is coincident with similar shifts in a host of geochemical proxies (δ13C, δ18O, δ44/40Ca, Sr/Ca, Mn/Sr, U/Ca). Despite these broad similarities between sections, there are important differences in the proxies between water depths that may be linked to changes in carbonate diagenesis. Specifically, we find the excursion's magnitude is largest in slope environments where diagenesis is sediment-buffered and smaller in shallow-water settings dominated by fluid-buffered diagenesis. The transgression that accompanied the Shuram CIE is consistent in amplitude (∼10-100s m) and duration (>1 My) with eustatic fluctuations driven by plate reorganization. These coupled geochemical and stratigraphic observations argue against meteoric and burial diagenesis as drivers for the excursion; instead, they are best explained by global changes to the locus and intensity of photosynthetic primary productivity in shallow-water environments and do not necessarily require large changes in global climate or marine redox.
KW - Ediacaran
KW - Shuram excursion
KW - carbonate geochemistry
KW - diagenesis
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U2 - 10.1016/j.epsl.2022.117368
DO - 10.1016/j.epsl.2022.117368
M3 - Article
AN - SCOPUS:85123047778
SN - 0012-821X
VL - 579
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
M1 - 117368
ER -