Songpan–Ganzi accretionary complex
This terrane represents a giant ‘‘suture knot’’ and comprises
huge thicknesses of accretionary complex rocks and volcanic
arc rocks constructed over trapped remnant Palaeo-Tethyan
oceanic lithosphere and underthrust continental lithosphere of
the surrounding crustal blocks. The rocks filling the ancient
basin comprise some Permian deep-sea sedimentary rocks but
are largely Triassic ophiolitic me´lange, flysch and molasse. The
Permo–Triassic sequence represents a basin filling and
shallowing sequence culminating in latest Triassic paralic
deposits (Go¨ru¨ r and Sengo¨ r, 1992). It has been suggested
(Nie et al., 1995) that exhumation of the Qinlin–Dabei
orogenic zone contributed huge amounts of Triassic sediment
to the Songpan–Ganzi basin.