The Tian Shan region was identified as the source of Permian fluvial-lacustrine fills in
the greater Turpan-Junggar basin. Thin-section petrographic study of thirty-six fine to very
coarse lithic arenites from Upper Permian-Basal Triassic Wutonggou low-order cycle suggests
both distant Tian Shan and local intrabasinal rift shoulders were sources. Two petrofacies are
identified on the basis of QFL composition. Petrofacies A (mean Q2F4L94, Qm2F4Lt94,
Qm42P57K1, and Qp0Lv49Ls51) occurs in the lower Wutonggou low-order cycle, which is
characterized by repetitive shifts between fluvial and deltaic depositional cycles. Petrofacies B
(mean Q26F9L65, Qm17F9Lt74, Qm65P25K10, and Qp13Lv55Ls32) occurs in the upper Wutonggou
low-order cycle, which is dominated by deltaic depositional cycles. Abundant mudrock and
basaltic lithics in Petrofacies A suggest intrabasinal rift shoulders were the primary source for the
lower Wutonggou low-order cycle. During the deposition of lower Wutonggou, the greater
Turpan-Junggar Basin was probably composed of highly partitioned grabens and half-grabens,
similar to the Quaternary Basin and Range Province of the western U.S. The abrupt increase in
quartz and decrease in basaltic lithics, coupled with changes in paleocurrents and depositional
style in the upper Wutonggou low-order cycle, suggest a different catchment with a larger
drainage fed the Wutonggou lake. The grabens and half-grabens during the deposition of upper
Wutonggou were more interconnected, receiving sediments derived from both distant Tian Shan
and local rift shoulders. The documented data best support a rift model, but the underlying cause
of rifting remains to be examined. / Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Geology.
| Identifer | oai:union.ndltd.org:WICHITA/oai:soar.wichita.edu:10057/5178 |
| Date | 12 1900 |
| Creators | Guan, Wei |
| Contributors | Yang, Wan |
| Publisher | Wichita State University |
| Source Sets | Wichita State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Format | ix, 102 p. |
| Rights | Copyright Wei Guan, 2011. All rights reserved |
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