Provenance and depositional environments of the upper Permian-lowermost Triassic fluvial and lacustrine sandstones, Wutonggou low-order cycle, Bogda Mountains, NW China

<p>"This work integrates petrographic and fieldwork studies and documents the spatial and temporal distributions of compositions and textures of the upper Permian-lowermost Triassic fluvial-lacustrine sandstones, Wutonggou low-order cycle (WTG LC), Bogda Mountains, NW China. In the first part, three petrofacies are identified on the basis of the relative abundances of quartz, feldspar, and lithics and conglomerate compositions and paleocurrent directions are documented. These data indicate that rocks of the eastern North Tianshan Suture (ENTS) and rift shoulders were the provenance lithology. Moreover, the upsection changes of petrofacies and conglomerate compositions suggest that the lithology of ENTS changed. During approximately Wuchiapingian, the eastern part of ENTS included the subduction complex, whereas the western part contained the undissected volcanic arc. During approximately Changhsingian to early Induan, the eastern part of ENTS was dominated with the transitional volcanic arc and subordinate with the subduction complex, whereas the subduction complex was exposed in the western part of ENTS. The second part documents the textural characteristics of the sandstones of WTG LC. Textures of different petrofacies are different in grain size, sorting, roundness, and textural maturity, indicating provenance is a major control factor in sandstone textures. Moreover, each petrofacies is subdivided into littoral/beach, deltaic, and fluvial sedimentary facies, of which the textural characteristics are similar. This work improves our understanding of the nature and the unroofing history of ENTS and factors in controlling compositions and textures of fluvial-lacustrine sandstones"--Abstract, page iv.</p>

Name thesis:degree_name

Ph. D. in Geology and Geophysics

Grantor

Missouri University of Science and Technology

Author dc:creator

• Zheng, Dongyu

• Bogda Mountains
• Depositional environments
• Eastern North Tianshan Suture
• NW China
• Provenance
• Wutonggou
• Geology
• Sedimentology

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/2800

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-3805