DOI: 10.1016/j.epsl.2021.116956
论文题名: Fingerprinting local controls on the Neoproterozoic carbon cycle with the isotopic record of Cryogenian carbonates in the Panamint Range, California
作者: Nelson L.L. ; Ahm A.-S.C. ; Macdonald F.A. ; Higgins J.A. ; Smith E.F.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 566 语种: 英语
中文关键词: carbon isotopes
; chemostratigraphy
; Cryogenian
; Death Valley
; diagenesis
; dolomitization
英文关键词: Calcite
; Carbonation
; Glacial geology
; Lime
; Organic carbon
; Sedimentology
; Sediments
; $+13$/C
; California
; Carbon isotopes
; Chemostratigraphy
; Cryogenian
; Death Valley
; Dolomitization
; Isotope values
; Marinoan
; Neoproterozoic
; Isotopes
; carbon cycle
; carbon isotope
; carbonate
; chemostratigraphy
; diagenesis
; dolomitization
; isotopic composition
; Proterozoic
; California
; Death Valley
; Panamint Valley
; United States
英文摘要: 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. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165615
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth and Planetary Sciences, Johns Hopkins University, Olin Hall, Baltimore, MD 21218, United States; Department of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544, United States; Department of Earth Science, University of California Santa Barbara, Webb Hall, Santa Barbara, CA 93106, United States
Recommended Citation:
Nelson L.L.,Ahm A.-S.C.,Macdonald F.A.,et al. Fingerprinting local controls on the Neoproterozoic carbon cycle with the isotopic record of Cryogenian carbonates in the Panamint Range, California[J]. Earth and Planetary Science Letters,2021-01-01,566