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GEOREF RECORD

Cryptic climatic signatures and tectonic controls on Cryogenian diamictites in the NW Tarim Craton, China

Wu Guanghui, D. P. Le Heron, Yang Liuyun, Luo Bingxu, Xiao Yang and Wang Bin
Cryptic climatic signatures and tectonic controls on Cryogenian diamictites in the NW Tarim Craton, China
Journal of the Geological Society of London (March 2018) 175 (4): 642-658

Abstract

Unravelling the origins of Cryogenian diamictites is vital in determining their significance in a snowball Earth context and their relationship to environmental processes. Here, we present new sedimentological and geochemical data for the Cryogenian sedimentary rocks from the Tarim Craton, NW China. The diamictite member of the East Qiaoenbrak Formation contains (1) granitic pebbles with high sphericity, (2) well-developed stratification and (3) bed-scale grain-size changes suggesting cyclicity; also, (4) ice-rafted debris is conspicuously absent. Rather than deposits of direct glacial origin, the succession is instead interpreted as a subaqueous fan complex. The major and trace element ratios and REE patterns are consistent throughout 22 sampled intervals in the Qiaoenbrak Group, suggesting a uniformly felsic source area, probably from an island arc. Chemical index of alteration (CIA) analysis indicates low CIA values (49.5-54.3, average 51.6) throughout the Qiaoenbrak Group. We suggest that both the Qiaoenbrak Group and Yuermeinak Formation were deposited during the Marinoan glaciation, in a long-lasting cold and dry interval. It is likely that the Qiaoenbrak Group was deposited in a fault-controlled basin adjacent to an active continental margin, although the material may ultimately have derived from a glacial source (e.g. outwash).


ISSN: 0016-7649
EISSN: 2041-479X
Coden: JGSLAS
Serial Title: Journal of the Geological Society of London
Serial Volume: 175
Serial Issue: 4
Title: Cryptic climatic signatures and tectonic controls on Cryogenian diamictites in the NW Tarim Craton, China
Affiliation: Sun Yat-sen University, School of Marine Sciences, Guangzhou, China
Pages: 642-658
Published: 20180302
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 83
Accession Number: 2018-037191
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect., strat. cols., 1 table, geol. sketch map
N40°49'60" - N41°10'00", E79°15'00" - E79°30'00"
Secondary Affiliation: University of Vienna, AUT, AustriaPetroChina Tarim Oilfield Company, CHN, China
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 201820
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