کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4406796 | 1307320 | 2016 | 7 صفحه PDF | دانلود رایگان |
Uranium-lead (U–Pb) dating was conducted on zircons in tuff layers and sandstone samples from the uppermost Liantuo Formation and in a tillite sample from the lowermost Nantuo Formation in Three Gorges area, South China, using SHRIMP and LA-ICP-MS techniques. Zircons from these samples yielded age spectrum (within 1000 Ma) of ∼890, ∼830, ∼780, ∼730, and 646 Ma. Zircons from the Liantuo tuffs have a weighted mean 206Pb/238U age of 734.1 ± 8.1 Ma (2σ, n = 7, MSWD = 0.48), which was regarded as the best estimation of the upper boundary age of the Liantuo Formation. Combining with previous geochronologic data, the Liantuo Formation was proposed to be a pre-Chang′an glaciation unit, and it is comparable to the middle-upper Banxi/Danzhou Group in South China.
Journal: Chemie der Erde - Geochemistry - Volume 76, Issue 1, March 2016, Pages 103–109