Cosmogenic nuclide burial ages and provenance of the Xigeda paleo-lake

Implications for evolution of the Middle Yangtze River

Ping Kong*, Darryl E. Granger, Fu Yuan Wu, Marc W. Caffee, Ya Jun Wang, Xi Tao Zhao, Yong Zheng

*Corresponding author for this work

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Hundred-meter-thick lacustrine sediments are widespread along the Middle Yangtze River. The distribution of these sediments suggests that an event blocked the river, forming a lake stretching 160 km from east to west and 110 km north to south, with a depth of ≥ 500 m. Using the cosmogenic nuclides 10Be and 26Al we have dated the time of burial of the lacustrine sediments and fluvial gravels beneath the sediments. Our results indicate a deposition age for these sediments between 1.34 and 1.58 Ma. Studies of zircon U-Pb age distributions within lacustrine sediments and fluvial sands related to the paleo-lake formation show diverse provenances from the upper Yangtze River and Yalong River, a major tributary of the Yangtze River. These deposits contain geologic fingerprints that allow identification of the source region of the lacustrine deposits and fluvial sands. Our results support the reversal of the Middle Yangtze River before the paleo-lake formation. We hypothesize that the geologic event that dammed the originally southward flow was the lateral movement of Chenghai fault in the Dali fault system initiated in early Quaternary. Water eventually cut through the spillway and flowed to the east.

Original languageEnglish
Pages (from-to)131-141
Number of pages11
JournalEarth and Planetary Science Letters
Volume278
Issue number1-2
DOIs
Publication statusPublished - 15 Feb 2009
Externally publishedYes

Keywords

  • Burial age
  • cosmogenic nuclide
  • Dali system
  • Xigeda
  • Yangtze River
  • zircon U-Pb age

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