气候变化领域集成服务门户(CCPortal): A multi-basin redox reconstruction for the Miocene Monterey Formation; California; USA

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DOI	10.1016/j.palaeo.2019.01.031
	A multi-basin redox reconstruction for the Miocene Monterey Formation; California; USA
	Hancock L.G.; Hardisty D.S.; Behl R.J.; Lyons T.W.
发表日期	2019
ISSN	0031-0182
起始页码	114
结束页码	127
卷号	520
英文摘要	Deposition of the Miocene Monterey Formation into numerous basins provides an ideal opportunity to study how preservation of geochemical signatures varies within and among basins as a function of local and global climatic and oceanic conditions. This study presents commonly employed redox indicators, including iron (Fe) speciation and redox-sensitive trace metal concentrations (Mo, U, V), to constrain paleoredox conditions from three Monterey locations: the Santa Barbara Basin, the Santa Maria Basin, and the San Joaquin Basin. The Fe speciation geochemistry of the Santa Barbara and Santa Maria Basin sediments are consistent with a wide range of redox conditions from suboxic to euxinic. These results, in combination with associated phosphorites and trace metal enrichment patterns, indicate oscillatory redox conditions, perhaps with a chemocline that fluctuated above the sediment-water interface on seasonal or multi-year timescales. Overall, these sections were deposited in environments similar to modern phosphorite-forming and upwelling-dominated oxygen minimum zone settings like the Peru Margin. Geochemical evidence indicates that the San Joaquin Basin was generally more restricted and more stably anoxic compared to the other two basins, perhaps more analogous to the modern Cariaco Basin, at least for the studied interval. Iron speciation in the San Joaquin Basin reveals anoxia and euxinia over the entirety of the studied interval, although trace metal concentrations are generally at the low end of those typical of anoxic/euxinic conditions—consistent with a restricted connection with the open ocean. The one exception is an interval c. ~11.6 million years ago (Ma) with elevated concentrations of redox-sensitive elements that may represent a decrease in basin restriction or an increase in water column sulfide concentrations. The present-day California Margin does not achieve euxinic conditions in similar basinal settings comparable with these Monterey sections, suggesting fundamental differences for the Miocene California margin that may carry implications for global-scale oxygen deficiency in Miocene oxygen minimum zones. © 2019 Elsevier B.V.
语种	英语
scopus关键词	euxinic environment; geochemistry; hypoxic conditions; Miocene; oxygen minimum layer; reconstruction; redox conditions; sediment-water interface; speciation (chemistry); sulfide; trace metal; water column; Atlantic Ocean; California; California Margin; Cariaco Basin; Caribbean Sea; Monterey; Pacific Ocean; Peru Margin; San Joaquin Basin; Santa Barbara Basin; United States
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151029
作者单位	Department of Earth Sciences, University of California Riverside, Riverside, CA 92521, United States; Department of Earth and Environmental Sciences, Michigan State University, 288 Farm Lane Room 207, East Lansing, MI 48824, United States; Department of Geological Sciences, California State University Long Beach, Long Beach, CA 90864, United States
推荐引用方式 GB/T 7714	Hancock L.G.,Hardisty D.S.,Behl R.J.,et al. A multi-basin redox reconstruction for the Miocene Monterey Formation; California; USA[J],2019,520.
APA	Hancock L.G.,Hardisty D.S.,Behl R.J.,&Lyons T.W..(2019).A multi-basin redox reconstruction for the Miocene Monterey Formation; California; USA.Palaeogeography, Palaeoclimatology, Palaeoecology,520.
MLA	Hancock L.G.,et al."A multi-basin redox reconstruction for the Miocene Monterey Formation; California; USA".Palaeogeography, Palaeoclimatology, Palaeoecology 520(2019).