کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4725324 | 1639870 | 2011 | 9 صفحه PDF | دانلود رایگان |
Collision between the Indian and the Eurasian plates since the early Cenozoic produces one of the world’s most remarkable continental escarpments between the Tibetan Plateau and the adjacent Sichuan Basin. Yet Tertiary sediments are rare in the Sichuan Basin; the oldest preserved Late Cenozoic deposits called Dayi conglomerates directly overlie the Cretaceous or Jurassic red beds. Using cosmogenic 10Be and 26Al burial dating, we obtain deposition ages of ∼2.0 Ma and catchment erosion rates of ∼400 mm/ka for the Dayi conglomerates. Zircon U–Pb age distributions suggest derivation of these conglomerates from the Songpan-Ganzi flysch, the Pengguan complex and Late Permian and Triassic granite plutons in the headwater regions of the Min Jiang (Jiang, a Chinese term, means river). The formation of the poorly-sorted, sub-angular to sub-rounded and tens-centimeter-sized deposits in the western margin of the Sichuan Basin, after long distance transportation, is best explained by glacial activity ∼2.0 Ma ago in east Tibet.
► Dayi conglomerates were deposited in the Sichuan Basin ∼2.0 Ma ago.
► Provenances of Dayi conglomerates lie in the headwater regions of the Min Jiang.
► Formation of Dayi conglomerates relates to Early Quaternary glaciations in east Tibet.
► The control of denudation of the Longmen Shan is tectonics, rather than climate.
Journal: Quaternary Geochronology - Volume 6, Issues 3–4, June–August 2011, Pages 304–312