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Calibrating the terminations of Cryogenian global glaciations

Zhou Chuanming, Magdalena H. Huyskens, Lang Xianguo, Shuhai Xiao and Qing-Zhu Yin
Calibrating the terminations of Cryogenian global glaciations
Geology (Boulder) (February 2019) 47 (3): 251-254


Cryogenian Sturtian and Marinoan glacial and associated strata record the most severe paleoclimatic events in Earth history and are the main test ground of the snowball Earth hypothesis (SEH). The SEH predicts that both Sturtian and Marinoan deglaciations were globally synchronous, rapid, and catastrophic. The sharp transition from glacial diamictite to the overlying cap dolostone represents a key event during these deglaciations. Thus, a positive test for globally synchronous deglaciation requires high-precision radiometric dates to tightly bracket this transition on each paleocontinent and within every substantial sedimentary basin; however, such high-resolution dates are scarce and have limited stratigraphic and paleogeographic coverage. Here, we report two high-precision U-Pb zircon chemical abrasion-isotope dilution-thermal ionization mass spectrometry ages of 658.80+ or -0.50 Ma and 634.57+ or -0.88 Ma from tuffaceous layers that occur, respectively, within the cap dolostone atop the Tiesi'ao diamictite (Sturtian age) and at the topmost Nantuo diamictite (Marinoan age) in South China. The 658.80+ or -0.50 Ma age represents a high-precision minimum age constraint on the termination of the Sturtian-age glaciation. The 634.57+ or -0.88 Ma age and a previously published age of 635.23+ or -0.57 Ma from the topmost cap dolostone are indistinguishable within uncertainty, and together they provide tight constraints on the termination of the Marinoan glaciation in South China at ca. 635 Ma and directly bracket the duration of the cap dolostone to be <106 yr. The new data support the rapid termination of the Marinoan glaciation in South China and are consistent with global synchroneity of Cryogenian deglaciation events.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 47
Serial Issue: 3
Title: Calibrating the terminations of Cryogenian global glaciations
Affiliation: Chinese Academy of Sciences, Nanjing Institute of Geology and Palaeontology, CAS Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing, China
Pages: 251-254
Published: 20190206
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 32
Accession Number: 2019-014770
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2019091
Illustration Description: illus. incl. geol. sketch map
N24°12'11" - N24°12'16", E102°28'32" - E102°28'32"
N28°09'35" - N28°09'35", E108°55'05" - E108°55'05"
Secondary Affiliation: University of California-Davis, USA, United StatesVirginia Polytechnic Institute and State University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201910
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