Sequence stratigraphy and tectonic evolution of the Triassic strata in the Tanggula Mountain area, Xizang

The Triassic carbonate-siliciclastic strata in the Tanggula Mountain area are separated, by three regional tectonic-sequence boundaries (Ta, Td and Tf) and three sequence boundaries (Tb, Tc and Te), into two supersequences and five sequences. Supersequence 1 dominated by flysch formations as the products formed during the initial collision of the Jinshajiang suture zone and sedimentary responses to the tectonic events of downwarping and settlement in the early stage of the Triassic foreland basin marks the formation of the foreland basin in the Tanggula Mountain area during the Norian (Late Triassic). Supersequence 2 dominated by molasses and acidic volcanic formations occur as the sedimentary responses to the tectonic events of thrusting and uplifting in the foreland basin during the Triassic, implying that the sediments derived from the orogenic zones bypassed the foreland uplifts and migrated towards the back-uplift basin during the Rhaetian (Late Triassic).