T7 Bridging Two Continents: Geologic Configuration of the Tibetan Plateau Region Prior to the Indo-Asian Collision: Setting the Stage for Development of a High Elevation Plateau

Sunday, 1 November 2015
8:00 AM - 12:00 PM
Room 347/348

UTILIZING DETRITAL ZIRCON DATA TO UNDERSTAND INDISTINCT PROVENANCE AGE SIGNATURES THROUGHOUT THE EASTERN TIBETAN PLATEAU

Paper number: T7-4
Program: Technical Sessions
Time: 8:50 AM – 9:05 AM

Authors

Abstract

In detrital zircon U-Pb geochronology investigations, distinct age populations are coupled with similar plutonic ages from geographically plausible sources to establish provenance, paleo-drainage patterns and regional tectonic histories. 765 zircon U-Pb ages obtained by LA-ICP-MS and LA-ICP-SC are used to investigate sedimentary provenance and maximum depositional age of the West Ganzi (WGB) and East Ganzi (EGB) basins, northern Yidun Arc Terrane, eastern Tibetan Plateau. The youngest age populations (maximum depositional age) from the WGB and EGB are 213.1±3.2 Ma and 211.4±2.1 Ma, respectively. The WGB and EGB detrital signatures have prominent peaks at 250-300 Ma, 400-450 Ma, 750-850 Ma, 900-950 Ma, 1.1-1.2 Ga, ~1.8 Ga, and 2.4-2.5 Ga.

The eastern Tibetan Plateau has numerous suture zones that separate terranes accreted to the southern margin of Asia during Mesozoic time, which contain Gondwana, Yangtze, and North China zircon signatures. The maximum depositional ages for the WGB and EGB coincide to numerous Late Triassic-Early Jurassic plutons throughout the Yidun Arc, Qiangtang and Songpan-Ganzi terranes, while prominent peaks show a mixture of Gondwana and Yangtze signatures. Comparison of detrital zircon data suggest that WGB and EGB sediment was sourced from the Paleozoic Zhongza Massif to the west and the local late Triassic Ganzi Pluton. Structural evaluations of the WGB and EGB’s boundaries suggest development in a peripheral foreland basin associated with eastward propagation of deformation resulting from the Yidun Arc Terrane and the Gondwana-derived Qiangtang Terrane during the Mid-late Triassic through earliest Jurassic time.