@article{3d0a81923edb432ebe6fc2e0a2d70b66,
title = "Fingerprinting local controls on the Neoproterozoic carbon cycle with the isotopic record of Cryogenian carbonates in the Panamint Range, California",
abstract = "Neoproterozoic carbon isotope excursions are commonly attributed to changes in the global fraction of organic carbon burial associated with climate instability and/or oxygenation. Here we show that carbonate sediment deposited during the ca. 661 – <651 Ma Cryogenian non-glacial interlude between the Sturtian and Marinoan glaciations exhibit lateral offsets in carbonate-carbon isotope values from coeval units by as much as 10‰. Within the Thorndike submember of the Cryogenian succession in the Panamint Range, California, USA, carbonate-carbon isotope values can be linked to a laterally discontinuous dolomitization front: limestones exhibit δ13Ccarb values of ∼+4 to +9‰, whereas values of stratigraphically equivalent dolostones are consistently lower, between ∼-4 and +4‰. Field observations and analyses of clasts from the overlying Marinoan glacial diamictite show that the offset in δ13Ccarb values resulted from pre- to syn-Marinoan dolomitization. Further, δ44/40Ca and δ26Mg data indicate that this isotopic variability resulted from sediment-buffered diagenesis. We propose that extremely positive δ13Ccarb values record local primary productivity within restricted platform surface waters and/or oxygenated pore fluids and negative values reflect anaerobic remineralization of organic carbon within sediment pore waters. In this scenario, neither the original calcite/aragonite nor subsequent dolomite precipitates of the Thorndike submember record δ13Ccarb values that are representative of global Cryogenian seawater, and instead they archive the evolution of local dissolved inorganic carbon pools.",
keywords = "Cryogenian, Death Valley, carbon isotopes, chemostratigraphy, diagenesis, dolomitization",
author = "Nelson, {Lyle L.} and Ahm, {Anne Sofie C.} and Macdonald, {Francis A.} and Higgins, {John A.} and Smith, {Emily F.}",
note = "Funding Information: We thank the U.S. National Park Service at Death Valley National Park for a sampling permit. Field work was carried out on ancestral homelands of the Timbisha Shoshone Tribe. LLN was supported by the Harvard University Booth Postgraduate Fellowship, National Geographic Society Early Career Grant CP-002ER-17, and National Science Foundation GRF DGE-1746891. EFS was supported by the National Science Foundation (NSF-1827715, NSF-2021064) and the Smithsonian Institution Buck Fellowship. ACA was supported by the Simons Foundation (SCOL 611878). The Harvard University Department of Earth and Planetary Sciences and Johns Hopkins University Department of Earth and Planetary Sciences provided additional support. We thank S. Goff and D. Schrag at Harvard University and D. Brenner at Johns Hopkins University for helping to analyze carbon and oxygen isotopes. We thank N. O'Connell and J. Haywood for enthusiastic assistance in the field, and C. Dwyer and S. Lobianco for assistance prepping samples for analyses. We thank Reggie and Bucky for faithful transportation, and Beck for companionship. D. Johnston provided helpful comments on an early version of the discussion. We are grateful to A. Prave and N. Planavsky for thoughtful reviews that improved this manuscript, and to L. Derry for editorial feedback and support. Funding Information: We thank the U.S. National Park Service at Death Valley National Park for a sampling permit. Field work was carried out on ancestral homelands of the Timbisha Shoshone Tribe. LLN was supported by the Harvard University Booth Postgraduate Fellowship, National Geographic Society Early Career Grant CP-002ER-17 , and National Science Foundation GRF DGE-1746891 . EFS was supported by the National Science Foundation ( NSF-1827715 , NSF-2021064 ) and the Smithsonian Institution Buck Fellowship. ACA was supported by the Simons Foundation (SCOL 611878 ). The Harvard University Department of Earth and Planetary Sciences and Johns Hopkins University Department of Earth and Planetary Sciences provided additional support. We thank S. Goff and D. Schrag at Harvard University and D. Brenner at Johns Hopkins University for helping to analyze carbon and oxygen isotopes. We thank N. O'Connell and J. Haywood for enthusiastic assistance in the field, and C. Dwyer and S. Lobianco for assistance prepping samples for analyses. We thank Reggie and Bucky for faithful transportation, and Beck for companionship. D. Johnston provided helpful comments on an early version of the discussion. We are grateful to A. Prave and N. Planavsky for thoughtful reviews that improved this manuscript, and to L. Derry for editorial feedback and support. Publisher Copyright: {\textcopyright} 2021 Elsevier B.V.",
year = "2021",
month = jul,
day = "15",
doi = "10.1016/j.epsl.2021.116956",
language = "English (US)",
volume = "566",
journal = "Earth and Planetary Science Letters",
issn = "0012-821X",
publisher = "Elsevier",
}