10.6084/m9.figshare.3452882
Maoyan Zhu
Maoyan
Zhu
Haifeng Wang
Haifeng
Wang
Chapter 33 Neoproterozoic glaciogenic diamictites of the Tarim Block, NW China
Geological Society of London
2016
Tarim Block
Tianshan Mountains record
Chapter 33 Neoproterozoic glaciogenic diamictites
Neoproterozoic successions
glaciogenic diamictites
Hankalchough diamictite
NW China Neoproterozoic glaciogenic outcrops
Hankalchough diamictites show
Tarim basin
582 Ma Gaskiers glaciations
Geology
2016-06-21 10:43:12
Dataset
https://geolsoc.figshare.com/articles/dataset/Chapter_33_Neoproterozoic_glaciogenic_diamictites_of_the_Tarim_Block_NW_China/3452882
<p>Neoproterozoic glaciogenic outcrops are mostly limited to the southwestern and northwestern margins of the Tarim basin and
the Tianshan Mountains. Only two glaciogenic diamictites are recorded in the Neoproterozoic successions from the Tielikeli
and Aksu-Wusi areas of the Tarim basin. The lower diamictite from the Polong Formation in the Tielikeli area is <em>c.</em> 800 m thick. The upper diamictite in the area is very thin (Yutang diamictite, 10 m; Yulmeinak diamictite, 51 m). In contrast
to the Tarim basin, the Neoproterozoic successions along the northern margin of the Tarim Block in the Tianshan Mountains
record three or four glaciogenic diamictites, which are well developed and crop out in the Qurugtagh area. Although the glaciogenic
nature of the oldest Beiyixi diamictite remains questionable, all other diamictites (Altungol, Tereeken and Hankalchough)
exhibit distinct glaciogenic sedimentary features. SHRIMP zircon U–Pb dating demonstrate that the Bayisi diamictite was deposited
between 740±7 Ma and 725±10 Ma, the Altungol and Tereeken diamictites between 725±10 Ma and 615±6 Ma, respectively, and the
Hankalchough diamictite between 615±6 Ma and <em>c.</em> 542 Ma. Carbonates atop the Altungol, Tereeken and Hankalchough diamictites show distinct C-isotopic values that are typical
for those recorded in ‘cap carbonates’ on other continents. The striking similarity between the cap carbonate of the Tereeken
and Marinoan-age Nantuo diamictites further support a 635 Ma ‘Marinoan’ age for the Tereeken glaciation. Unlike the 582 Ma
Gaskiers glaciations of Newfoundland, the Hankalchough diamictite is possibly <551 Ma, as suggested by C-isotope chemostratigraphy
and biostratigraphy, indicating that post-Marinoan glaciations on different continents may be diachronous.
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