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Cretaceous plutons that intrude the Central and Southern Pamirs record a long-lasting
magmatic history. Their zircons and those from Late Miocene xenoliths show that the
most distinct tectonic events were Cambro-Ordovician (~575-410 Ma), Triassic (~250-
200 Ma, due to subduction along the Jinsha suture and/or Triassic rifting (e.g. in the
Rushan Pshart/Bangong-Nujiang area and between the SW and SE Pamirs)), Middle
Jurassic (~200-150 Ma, due to subduction along the Rushan Pshart suture), and mainly
Cretaceous. The Cretaceous activity may have been bimodal, with peaks at ~120 Ma
and ~80 Ma. The Mid-Cretaceous event may reflect arc activity in Asia prior to the
accretion of the Karakorum block, probably along the Tirich Mir fault. The Late
Cretaceous magmatism may be a sign of flat-slab subduction along the Shyok suture
north of the Kohistan-Ladakh arc. Before India and Asia collided, the Pamir region from
the south Tien Shan to the Indus-Yarlung was an Andean-style plate margin. From the
Kunlun arc in the north to the southern Qiangtang block in the south, the Pamirs and
Tibet seem to have dominantly (meta)sedimentary crust, characterised by the Karakul-
Mazar/Sonpan-Ganze accretionary wedge rocks. The crust south of the southern
Qiangtang block is of likely granodioritic composition, reflecting long-lived subduction,
arc formation and Cretaceous/Tertiary underthrusting of arc segments beneath the
Qiangtang block.
The accretion history was accomplished by the final collision of India with Eurasia at
~55 Ma. The long lasting history as an active continental margin ended and the Pamirs
came into an intracontinental position. Crustal stacking in the Pamirs region initiated
shortly after the India-Asia collision and led to much more thickened crust than
previously thought (70-80 km). Due to crust thickening and successive melt generation,
several Tertiary intrusions penetrated the Pamirs. More widespread are leucogranites
in the South Pamirs, whereas localised migmatisation and melt generation led to
subalkaline and alkaline intrusions into Central Pamiran basement domes in the
Tertiary. The Tertiary magmatism was probably episodic with subalkaline intrusions in
Late Eocene/Oligocene and aplitic and basalt dyke emplacement around ~20-11 Ma.
Medium to high-grade metamorphism was about 20-15 Ma. Crustal shortening was
most extreme in the Pamiran region and strain is mostly concentrated along
rheologically weakened zone along the margins of the accreted crustal blocks. One
exception is the Central Pamirs with its basement anticlinoriums.
Apatite and zircon fission track ages support the above outlined accretion history.
Tertiary sedimentary rock samples and their determined grain ages highlight the
exhumation and cooling of the rising Kunlun after Early to Mid Palaeozoic arc accretion
and subduction related magmatism (peak ages in the Kunlun ~ 370 Ma). The Tien Shan
range was subject of two collisions in the Palaeozoic: an Early to Mid Palaeozoic
collision was only weakly detected in Tertiary Tien Shan sedimentary basins, but Late
Palaeozoic/Triassic cooling and exhumation after collision together with coeval basin
formation catching the sediments of the rising Tien Shan and Kunlun mountains is well
detectable in the Tien Shan (~266-245 Ma). Triassic ages around ~242 Ma are also
recorded in Tertiary northern Qiangtang intramontane basins and can be related to
subduction of the Jinsha oceanic crust beneath the Qiangtang block and/or be related
to increased heat flow due to basin formation in several areas surrounding the
Qiangtang, Lhasa, and Kunlun regions. Mid-Jurassic peak ages, coupled with Jurassic