气候变化领域集成服务门户(CCPortal): Chromium isotope systematics and the diagenesis of marine carbonates

CCPortal

DOI	10.1016/j.epsl.2021.116824
	Chromium isotope systematics and the diagenesis of marine carbonates
	Wang C.; Reinhard C.T.; Rybacki K.S.; Hardisty D.S.; Ossa Ossa F.; Wang X.; Hofmann A.; Asael D.; Robbins L.J.; Zhang L.; Planavsky N.J.
发表日期	2021
ISSN	0012821X
卷号	562
英文摘要	Stable chromium (Cr) isotopes have emerged as a new tool for tracking broad-scale changes in Earth's surface oxygen levels. Carbonates are one proposed sedimentary Cr isotope archive. In order to contribute to the development of a robust framework for interpreting carbonate Cr isotopic compositions and evaluating their ability to record the global redox state, we explored Cr isotope systematics of modern and Archean carbonate successions—representing end member oxic and anoxic Earth system states. We generated new data from carbonate platform sediments from the Great Bahama Bank with variable post-depositional histories to better understand the effects of diagenetic alteration on carbonate-bound Cr and its isotopic composition in a modern well-oxygenated ocean-atmosphere system. More specifically, we investigated the effects of dolomitization and aragonite-to-calcite neomorphism in marine and meteoric fluids. We also present δ53Cr values from three carbonate successions, the ∼3.0 Ga Chobeni Formation (South Africa), ∼2.8 Ga Mosher Carbonate Formation (Canada), and ∼2.65 Ga Cheshire Formation (Zimbabwe), that were deposited under an anoxic atmosphere. We find that modern Bahamian carbonates have a large range of almost exclusively positive δ53Cr values (from −0.04 to 2.88‰). The δ53Cr values appear to be altered during both meteoric diagenesis and dolomitization but there may also be instances of rock-buffered conditions that may best preserve depositional δ53Cr values. These observations provide a baseline for carbonate Cr isotope behavior in a well-oxygenated ocean-atmosphere system. Our Archean carbonate successions contain both positively fractionated and crustal δ53Cr values, ranging between −0.37 and 0.89‰. The Cr isotope fractionation observed in Archean strata is most plausibly linked to either non-redox dependent Cr isotope fractionation, local Cr redox cycling, late-stage diagenetic alteration, or some combination thereof. Given the significant effects of post-depositional alteration on the isotopic composition of carbonate-bound Cr, we suggest that Cr isotope values from ancient carbonate sediments should be generally interpreted with caution and cannot be straightforwardly linked to changes in atmospheric oxygen abundance. © 2021 Elsevier B.V.
关键词	atmospheric oxygen abundance Cenozoic and Archean chromium isotope diagenesis marine carbonates
英文关键词	Calcite; Carbonation; Deposition; Isotopes; Sedimentology; Atmospheric oxygen; Carbonate formations; Carbonate platforms; Carbonate sediments; Carbonate successions; Diagenetic alteration; Isotopic composition; Ocean-atmosphere system; Gallium compounds; aragonite; atmosphere-ocean system; calcite; carbonate; chromium; diagenesis; dolomitization; isotopic composition; redox conditions; sediment chemistry; Bahamas; Canada; South Africa
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203324
作者单位	Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; Department of Earth and Planetary Sciences, Yale University, New Haven, CT, United States; Innovation Academy for Earth Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China; School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, United States; Bureau of Land Management, Phoenix, AZ, United States; Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, United States; Department of Geosciences, University of Tuebingen, Tuebingen, Germany; Department of Marine Sciences, University of South Alabama, Mobile, AL, United States; Dauphin Island Sea Lab, Dauphin Island, AL, United States; Department of Geology, University of Johannesburg, Johannesburg, South Africa; Department of Geology, University of Regina, Regina, SK, Canada
推荐引用方式 GB/T 7714	Wang C.,Reinhard C.T.,Rybacki K.S.,et al. Chromium isotope systematics and the diagenesis of marine carbonates[J],2021,562.
APA	Wang C..,Reinhard C.T..,Rybacki K.S..,Hardisty D.S..,Ossa Ossa F..,...&Planavsky N.J..(2021).Chromium isotope systematics and the diagenesis of marine carbonates.Earth and Planetary Science Letters,562.
MLA	Wang C.,et al."Chromium isotope systematics and the diagenesis of marine carbonates".Earth and Planetary Science Letters 562(2021).