DOI: 10.1016/j.epsl.2018.04.043
Scopus记录号: 2-s2.0-85047099299
论文题名: Sulfur isotope change across the Early Mississippian K–O (Kinderhookian–Osagean) δ13C excursion
作者: Maharjan D. ; Jiang G. ; Peng Y. ; Nicholl M.J.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 494 起始页码: 202
结束页码: 215
语种: 英语
英文关键词: carbon isotope excursion
; Early Mississippian
; Great Basin
; sulfur isotopes
; western United States
Scopus关键词: Organic carbon
; Oxygen
; Pyrites
; Sea level
; Stratigraphy
; Sulfur
; Sulfur compounds
; Carbon isotope excursions
; Great Basin
; Mississippians
; Sulfur isotope
; Western United States
; Isotopes
英文摘要: Paired carbonate associate sulfate (CAS) sulfur isotopes (δ34SCAS), pyrite sulfur isotopes (δ34SPY) and CAS oxygen isotopes (δ18OCAS) across the Early Mississippian K–O δ13C excursion are documented from two sections of a west-dipping carbonate ramp in the southern Great Basin, western U.S.A. A 4–6‰ positive δ34SCAS anomaly, accompanied by negative shifts in δ34SPY and δ18OCAS is found within the K–O δ13C excursion. In the section with a broader δ13C excursion, Δ34S (Δ34S=δ34SCAS–δ34SPY) increases from 15‰ to 45‰ and δ13Ccarb drops from 7‰ to 4‰ at the same stratigraphic interval. If this δ34SCAS anomaly represents a global phenomenon, the large magnitude (4–6‰) and short duration (shorter than that of δ13C) suggest an unusual pyrite burial event that expanded from sediments to the ocean water column. In this scenario, the areal and volumetric expansion of sulfate reduction and pyrite burial was likely triggered by abundantly available organic matter near the peak of the K–O δ13C excursion, during which organic carbon production and burial may have reached a maximum, thus substantially expanding the oxygen minimum zone (OMZ). Numerical simulations suggest that pyrite burial rates 2.5–5 times higher than that of the modern ocean followed by sulfide oxidation are required to produce the observed δ34SCAS anomaly in a sulfate-rich ([SO4] ≥28 mM) Early Mississippian ocean. Alternatively, the sulfur and CAS oxygen isotope anomalies may record local sulfur cycling in a foreland basin where changes in weathering input and bottom-water redox conditions in response to sea-level fall and cooling resulted in isotope changes. In both scenarios (either local or global), the integrated carbon, sulfur, and CAS-oxygen isotope data suggest a much more dynamic sulfur cycle across the K–O δ13C excursion than has been previously suggested. © 2018 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109836
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Geoscience, University of Nevada, Las Vegas, NV 89154-4010, United States; Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, United States
Recommended Citation:
Maharjan D.,Jiang G.,Peng Y.,et al. Sulfur isotope change across the Early Mississippian K–O (Kinderhookian–Osagean) δ13C excursion[J]. Earth and Planetary Science Letters,2018-01-01,494