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postulated that the Safed Khers area of Afghanistan hosts similar basement domes,
and the Band-e Bayan and Farah Rod zones of that country correlate with the Mesozoic
Central Pamirs and Qiangtang cover sequences.
(5) Calc-alkaline granitoids (~190-150 Ma) cut the southern Central and northern
Southeast Pamirs. They intruded into the eastern Pshart oceanic basin-arc sequence
and formed the Rushan Pshart arc. The Farah Rod zone of Afghanistan likely represent
the western continuation of this setting and granitoids of the southern Qiangtang block
of Tibet (~170-160 Ma) epitomize its eastern prolongation. These successions and
intrusives of the Rushan Pshart zone record the closure of probably several small,
laterally arranged transpressive basins reaching into the Bangong-Nujiang zone
between the Qiangtang and Lhasa blocks in Tibet. These basins were finally consumed
by Mid-Jurassic times.
(6) Zircons of Late Miocene xenoliths and of Cretaceous plutons from the central and
southern Pamirs suggest a prolonged magamtic history of the region comprising four
main phases: Cambro-Ordovician (~575-410 Ma); Triassic (~250-200 Ma), related to
subduction along the Jinsha suture and/or Triassic rifting; Jurassic (~200-150 Ma),
related to subduction along the Rushan Pshart suture; and Cretaceous. The Cretaceous
activity may comprise peaks at ~120 Ma and ~80 Ma, reflecting arc activity prior to
accretion of the Karakorum block probably along the Tirich Mir fault and flat-slab
subduction along the Shyok suture north of the Kohistan-Ladakh arc respectively.
The above outlined accretion history is supported by fission track ages of detrital
apatites and zircons depicting four major phases of tectonic activity:
(a) Age populations of ~370 Ma from Tertiary sedimentary basins of the northern
Pamirs and northern Central Pamirs are interpreted to be related to the first, northern
Kunlun arc stage.
(b) A Permo-Triassic cluster ranging from ~266 to 242 Ma was detected in all studied
regions from the southern Tien Shan to the eastern Pamirs. These ages argue for
Triassic rifting and/or Triassic southward subduction along the Jinsha suture.
(c) Jurassic age populations from 170-145 Ma occur in Tertiary sedimentary rocks of the
South Tien Shan, Kunlun, southern Qiangtang, and Rushan Pshart zone. They are
attributed to the Rushan Pshart arc formation and Rushan Pshart basin closure in Mid-
Jurassic, which entailed the collision of the Central Pamirs and southeast Pamirs. The
coincident collision of the Qiangtang and Lhasa blocks caused for instance Mid-
Jurassic compressive deformation in the Kunlun mountains.
(d) Late Cretaceous fission track ages were determined on apatites of Tertiary
intramontane basin sediments from the South Tien Shan and on zircons from intrusive
rocks of the northern and southern Central Pamirs. These ages may reflect limited
exhumation induced by underthrusting of the southeastern Pamirs beneath the
southern margin of the Central Pamirs and by intracontinental subduction of the
Karakul-Mazar and Jinsha lithosphere underneath the northern margin of the Central
Pamirs. This compression was probably triggered by flat-slab subduction along the
Shyok suture, between the Karakoum and Kohistan-Ladakh terranes.