The Gyirong basin, southern Tibet, contains the record of Miocene-Pliocene exhumation,
drainage development, and sedimentation along the northern flank of the Himalaya. The tectonic controls
on basin formation and their potential link to the South Tibetan Detachment System (STDS) are not well
understood. We use detrital zircon (ZFT) and apatite (AFT) fission-track analysis, together with detrital zircon
U-Pb dating to decipher the provenance of Gyirong basin sediments and the exhumation history of the
source areas. Results are presented for nine detrital samples of Gyirong basin sediments (AFT, ZFT, and U-Pb),
two modern river-sediment samples (ZFT and AFT), and six bedrock samples (ZFT) from transect across
the Gyirong fault bounding the basin to the east. The combination of detrital zircon U-Pb and fission-track
data demonstrates that the Gyirong basin sediments were sourced locally from the Tethyan Sedimentary
Sequence. This provenance pattern indicates that deposition was controlled by the Gyirong fault, active since
~10 Ma, whose vertical throw was probably <~5000 m, rather than being controlled by normal faults
associated with the STDS. The detrital thermochronology data contain two prominent age groups at ~37–41
and 15–18 Ma, suggesting rapid exhumation at these times. A 15–18 Ma phase of rapid exhumation has been
recorded widely in both southern Tibet and the Himalaya. A possible interpretation for such a major regional
exhumation event might be detachment of the subducting Indian plate slab during the middle Miocene,
inducing dynamic uplift of the Indian plate overriding its own slab.