Himalaya: cross-section

                                        Himalaya: a transect

*Karakorum Range

  --between Kun Lun and Northern Suture

  --remains of an Andean margin, thrusted to south over arc remnants

*Northern Suture

  --belt of mélange, mafic and ultramafic rocks, slate

                                        Himalaya: a transect

*Trans-Himalaya

  --plutonic belt, comprising Andean batholiths

  --diverges in the west around the Ladakh-Kohistan arc

  --Cretaceous Kangdese (Gandîse) granite - subduction of Tethyan ocean floor

*Indus-Zangbo (Yarlung-Tsangpo) suture zone

  --narrow discontinuous belt of ophiolite, blueschist facies rocks at the ends; forearc rocks in the
  central Himalaya



*Higher Himalaya

  --Central Crystalline Belt - core zone amphibolite facies gneiss

  --Indian in origin, basement + cover

  --Tethys Himalaya - stack of south-vergent thrust sheets

  --complete 10 km thick Cambrian to Eocene sequence

  --sedimentary rocks on northern margin of protoIndia

  --allochthonous ophiolitic rocks - derived from Indus-Zangbo suture zone, preserved as klippen. 
  Immature ophiolites.

  --granite plutons - very high ^87Sr/^86Sr ratios

  --derived from melting of crust.



*Lower Himalaya

  --below Main Central Thrust, above Main Boundary Thrust

  --Proterozoic to Lower Paleozoic Indian miogeoclinal rocks

  --thrust south on to India

  --inverted isograds (hot thrusts)

*Sub-Himalaya

  --7 km thick unmetamorphosed molasse (Siwalik Molasse)

  --Oligocene to Holocene deformation (offset river terraces)

  --carried on Main Frontal Thrust

*Ganga (Indogangetic) Plain - Indus-Ganges River, undeformed.

                                      Himalaya: cross-section

                                              Himalaya

*the Himalaya provides a good look at c-c collisions

*world's youngest and highest mountain range

*world's fastest uplift rate (10 mm/a at Nanga Parbat)

*world's maximum relative relief (>6,000 m, Indus Valley)

*world's largest high plateau (Tibet, >5,000 m)

*(nice feature!) produced from almost orthogonal collision

*tectonic development in brief:

  --Late Triassic: North Tibet collided with Eurasia, Paleotethys Ocean closed, Kun Lun Range
  initiated

  --Jurassic to Early Tertiary: several oceans (or arms of oceans) opened and closed; terranes were
  moved across Tethys to the north

  --Eocene: Neotethys Ocean closing, India collided with Eurasia

  --Eocene to Holocene: India still pushing north into Asia.