Keywords and Phrases
Bogda Shan; Jiucaiyuan; Lower-Triassic; Provenance; Shaofanggou; Tian Shan
"The uppermost Carboniferous to Lower Triassic eolian-fluvial-lacustrine deposits of Turpan-Junggar Basin, NW China, record the non-marine sediment-filling processes in a continental rift basin in mid-latitude NE Pangea. This study focuses on the fluvial-lacustrine strata of the Lower Triassic Jiucaiyuan (JCY) and Shaofanggou (SFG) low-order cycles (LCs) in multiple half grabens at the southern and northern foothills of Bogda Shan. Outcrop, paleocurrent, and petrographic analyses indicate a southern provenance. Intermediate to felsic volcanic lithics and metamorphic lithics are interpreted as being derived from Tian Shan to the south while the sedimentary lithics originate from the local rift shoulders. The basaltic lithics may have originated from either location. The abrupt change from lacustrine depositional environment in the upper Wutonggou low-order cycle to fluvial depositional environment in the lower JCY LC records the disappearance or shallowing of the local lake in all four sections in the southern foothills of the Bogda Shan and may have been caused by a climatic shift to a drier climate. The abrupt to gradual change from fluvial to lakeplain depositional environments in the same sections in the lower SFG LC signifies the reappearance of the local lake and may have been caused by another climatic shift to a more humid climate. Overall fining upward from the JCY to SFG LCs and the occurrence of Calcisols in the mid to upper JCY LC and entire SFG LCs suggests tectonic quiescence during this time, and Calcisols also indicate a semiarid to sub-humid climate and landscape stability"--Abstract, page iii.
Wronkiewicz, David J.
Hogan, John Patrick
Geosciences and Geological and Petroleum Engineering
M.S. in Geology and Geophysics
Missouri University of Science and Technology
xii, 276 pages
© 2017 Jaimeson Grigaitis Fredericks
Thesis - Open Access
Electronic OCLC #
Fredericks, Jaimeson Grigaitis, "Provenance and depositional environments of fluvial-lacustrine deposits in a non-marine rift basin, Lower-Triassic Jiucaiyuan and Shaofanggou low-order cycles Bogda Shan, NW China" (2017). Masters Theses. 7641.