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GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 59-9
Presentation Time: 9:00 AM-5:30 PM

AGE AND EXTENT OF LANDSLIDE-DAMMED LAKE SEDIMENTS IN THE UPPER YELLOW RIVER ALONG THE MARGIN OF THE NORTHEASTERN TIBETAN PLATEAU, CHINA


GUO, Xiaohua1, FORMAN, Steven L.2, LAI, Zhongping3, LU, Yudong4 and LI, Xiaolin3, (1)Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of Ministry of Education, Chang'an University, Xi'an, 710054, China; Department of Geosciences, Baylor University, Waco, TX 76798, (2)Dept. of Geology, Baylor University, Waco, TX 76798, (3)School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China, (4)Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of Ministry of Education, Chang'an University, Xi'an, 710054, China, Xiaohua_Guo@Baylor.edu

<span"> This study documented up to six massive landslides within a 100 km reach of the upper Yellow River reflecting multiple causative factors. The initial pair of landslides (Dehenglong and Suozi) which dammed the Yellow River, appear simultaneous and contiguous and formed an upstream 46-km-long lake. These landslides occurred during a period of aggradation, and flowed across the valley floor at 160 m above the current river level which would be the tread of Terrace 4, ca. 80 ka. Therefore, when the two initial landslides were emplaced the water table was at least 160 m higher than today and was also during a period of strengthened monsoonal precipitation. These wetter conditions may be associated with elevated groundwater levels which would have lowered shear stress of sediments on steep slopes adjacent to the Yellow River. In turn, earthquake events from nearby capable faults may have been a causative factor for the two initial landslides that dammed the Yellow River. The rise in lake level from the landslide dam resulted in two additional landslides up stream (Xiazangtan and Kangyang). A landslide diamicton intercalated within silty landslide dammed-lake deposits indicated that these four landslides were penecontemporaneous, consistent with associated OSL ages of ca. 70 to 80 ka. Subsequently, a catastrophic breach of the landslide-dammed lake with an estimated maximum volume of 31,025 km3 dam may have generated an outburst flood with an estimated peak discharge of 2.9 ×107 m3/s and resulted possibly in downstream landslides. Currently, the steep slopes and the numerous impoundments along the upper reaches of the Yellow River remain source areas for mass movements, which may again dam the Yellow River and could instigate multiple overlapping processes related to regional hydrology, fluvial erosional thresholds and tectonic activity, potentially releasing a succession of landslides.

Session No. 59--Booth# 22

Recent Advances in Geomorphology, from the Mountains to the Coast (Posters)
Sunday, 25 September 2016: 9:00 AM-5:30 PM
Exhibit Hall E/F (Colorado Convention Center)
Geological Society of America Abstracts with Programs. Vol. 48, No. 7
doi: 10.1130/abs/2016AM-281877
© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.
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