气候变化领域集成服务门户(CCPortal): Atmospheric dust flux in northeastern Gondwana during the peak of the late Paleozoic ice age

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DOI	10.1130/B35636.1
	Atmospheric dust flux in northeastern Gondwana during the peak of the late Paleozoic ice age
	Abadi M.S.; Soreghan G.S.; Hinnov L.; Heavens N.G.; Gleason J.D.
发表日期	2021
ISSN	167606
起始页码	992
结束页码	1006
卷号	133 期号:2021-05-06
英文摘要	The silicate mineral fraction of shallow marine carbonates archives dust contributions to the Central Persian Terranes along the northeastern margin of Gondwana (~30°S paleolatitude), enabling reconstruction of atmospheric dust loading and circulation for intervals of the late Paleozoic ice age. The Central Persian Terranes hosted cyclic deposition of warm water carbonates from middle Pennsylvanian to earliest Permian time, and our data set includes two -28 m sections from the Moscovian and As-selian sampled at 20 cm intervals. Bounding surfaces between successive cycles (high-frequency sequences) are recognized by either abrupt basinward shifts in facies or subtle exposure features; these high-frequency sequences range from 1 m to 5 m thick and are interpreted to record glacioeustatic variations. Time series analysis of the dust fraction through the studied interval supports the hypothesis of orbital forcing for the dust signal. The stratigraphic pattern of the dust flux indicates minimal flux during interglacial highstands (0.19-0.27 g/cm2/ kyr) and peak flux during glacial lowstands (3.77-4.57 g/cm2/kyr) after accounting for hiatal time at sequence boundaries. Grain size analysis of the dust for all samples (n = 230) reveals modal sizes (volume-based) of 1-15 \|!m through the Moscovian interval and 10-75 \|!m through the Asselian interval. Dust deposition increased during glacial times relative to interglacial times by a factor of 16 to 19. Additionally, the Asselian interval exhibits higher dust flux overall relative to the Moscovian interval, which is interpreted to reflect the more extreme icehouse conditions of the Asselian. Variation in the dust content through the studied sections provides an indicator of temporal changes in atmospheric loading that varied at both glacial-interglacial and higher-frequency (<104 yr) scales. Geochemical data reveal that the Arabian-Nubian Shield and southwestern Pangaea (South America) are the most likely sources of dust deposition in the Central Persian Terranes, with sources shifting during different phases. Increased dust flux during glacials likely reflects multiple factors, including enhanced aridity in the source region, exposure of shelf regions, and potential changes in winds. However, the discrepancy in model reconstructions of the amplitude of glacial-interglacial dust variations indicates that increased production of dust sourced by dynamic glaciation played a large role in enhancing dust flux during glacial phases. © 2021 Geological Society of America. All Rights Reserved.
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/184671
作者单位	School of Geosciences, University of Oklahoma, 100 East Boyd Street, Norman, Oklahoma 73019, United States; Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, Virginia 22030, United States; Department of Atmospheric and Planetary Sciences, Hampton University, 21 East Tyler Street, Hampton, Virginia 23668, United States; Space Science Institute, 4750 Walnut St., Suite 205, Boulder, Colorado 80301, United States; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan 48109-1005, United States
推荐引用方式 GB/T 7714	Abadi M.S.,Soreghan G.S.,Hinnov L.,et al. Atmospheric dust flux in northeastern Gondwana during the peak of the late Paleozoic ice age[J],2021,133(2021-05-06).
APA	Abadi M.S.,Soreghan G.S.,Hinnov L.,Heavens N.G.,&Gleason J.D..(2021).Atmospheric dust flux in northeastern Gondwana during the peak of the late Paleozoic ice age.Bulletin of the Geological Society of America,133(2021-05-06).
MLA	Abadi M.S.,et al."Atmospheric dust flux in northeastern Gondwana during the peak of the late Paleozoic ice age".Bulletin of the Geological Society of America 133.2021-05-06(2021).