气候变化领域集成服务门户(CCPortal): From source to sink: Glacially eroded, Late Devonian algal “cysts” (Tasmanites) delivered to the Gulf of Mexico during the Last Glacial Maximum

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DOI	10.1130/B35587.1
	From source to sink: Glacially eroded, Late Devonian algal “cysts” (Tasmanites) delivered to the Gulf of Mexico during the Last Glacial Maximum
	Kohl B.; Curry B.B.; Miller M.
发表日期	2021
ISSN	167606
起始页码	849
结束页码	866
卷号	133 期号:2021-03-04
英文摘要	The source of reworked Devonian algal “cysts” in last glacial maximum (LGM) sediment in the Gulf of Mexico is traced to their host black shales, which ring the southwestern Great Lakes. The source-to-sink pathway includes intermediate storage in fine-grained LGM glacial lacustrine sediment and till. The “cysts” are pelagic chlorophyllous algae (Tasmanites and Leiosphaeridia), collectively referred to herein as tasmanitids. Radiocarbon dates of syndepositional Gulf of Mexico foraminifera, derived from accelerator mass spectrometry, bracket the Gulf of Mexico sediment age with common tasmanitids from 28.5 ± 0.6–17.8 ± 0.2 cal kyr B.P. Approximately 1400 km north of the Gulf of Mexico, tasmanitids are abundant in Upper Devonian black shales (New Albany, Antrim, and Ohio Shales) that ring the Michigan, Illinois, and Appalachian intracratonic basins. Tasmanitids were eroded from bedrock and incorporated in glacial sediment dating from ca. 28.0–17.6 cal kyr B.P. by the Lake Michigan, and Huron-Erie lobes of the Laurentide Ice Sheet. The physical characteristics of tas-manitids are ideal for long-distance transport as suspended sediment (density: 1.1–1.3 g/ cc, size ranging from 63 µm to 300 µm), and these sand-sized tasmanitids traveled with the silt-clay fraction. Thus, the source-to-sink journey of tasmanitids was initiated by sub-glacial erosion by water or friction, sequestering in till or glaciolacustrine sediment, re-entrainment and suspension in meltwa-ter, and final delivery in meltwater plumes to the Gulf of Mexico. River routes included the Mississippi, Illinois, Ohio, Wabash, Kas-kaskia, and many of their tributaries. Reworked Devonian tasmanitids are a previously unrecognized link between their occurrence in deep-water deposits of the Gulf of Mexico and the late Wisconsin glacial history of the Upper Mississippi Valley. We propose that tracking occurrences of tasmanitid concentrations from the source area to sink, along with adjunct proxies such as clay minerals, will facilitate a more refined analysis of the timing and duration of megafloods. This study also demonstrates that isotopically dead carbon, from reworked Devonian tas-manitid “cysts,” can contaminate radiocarbon dating of LGM bulk sediment samples toward older ages. © 2020. Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184689
作者单位	Department of Earth and Environmental Sciences, Tulane University, 6823 Street Charles Avenue, New Orleans, Louisiana 70118, United States; Illinois State Geological Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, Illinois 61820, United States; The irf group Inc., 2753 East 23rd Street, Tulsa, Oklahoma, 74114, United States; Department of Geosciences, University of Tulsa, 800 South Tucker Drive, Tulsa, Oklahoma, 74104, United States
推荐引用方式 GB/T 7714	Kohl B.,Curry B.B.,Miller M.. From source to sink: Glacially eroded, Late Devonian algal “cysts” (Tasmanites) delivered to the Gulf of Mexico during the Last Glacial Maximum[J],2021,133(2021-03-04).
APA	Kohl B.,Curry B.B.,&Miller M..(2021).From source to sink: Glacially eroded, Late Devonian algal “cysts” (Tasmanites) delivered to the Gulf of Mexico during the Last Glacial Maximum.Bulletin of the Geological Society of America,133(2021-03-04).
MLA	Kohl B.,et al."From source to sink: Glacially eroded, Late Devonian algal “cysts” (Tasmanites) delivered to the Gulf of Mexico during the Last Glacial Maximum".Bulletin of the Geological Society of America 133.2021-03-04(2021).