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.