The Qiangtang metamorphic belt in central Tibet: Evidence for large-magnitude translation and underplating of melange

beneath continental crust during flat-slab subductionPaul Kapp (University of Arizona)

An Yin & Craig Manning (UCLA), George Gehrels (UA)

To what extent can melange underthrust and be incorporated into continental crust?

The limited exposures of subduction-related rocks that demonstrably underplated continental crust may suggest that most subducted material

is recycled to mantle or that underplated rocks are rarely exhumed.

EAST(Shuang Hu)

CENTRAL(Rongma)

CENTRAL (Rongma)

CENTRAL (Rongma)

WEST (Gangma Co)

white specks are a herd of sheep

Summary of Preliminary Results

1. Sedimentary Provenance: similarities between N. + S. Qiangtang Carboniferous strata + melange detrital zircon age spectra

2. Metamorphic evolution: Consistently high-P; large range of T

3. Extent of normal faulting: Extensional shear zone equilibrated at high-P

If correct, the process of large-scale underthrusting and incorporation of melangeinto continental crust during flat-slab subduction would be directly validated