Late Cretaceous pelagic laminites at the northwestern margin of Indian plate, Pakistan: implications for basin bathymetry and ophiolite emplacement

2021 ◽  
Vol 36 (2) ◽  
Author(s):  
Sajjad Ahmad ◽  
Suleman Khan ◽  
Bilal Wadood ◽  
Asad Naseer ◽  
Muhammad Noman ◽  
...  

The Himalaya, the Karakoram and Tibet were assembled by the successive accretion to Asia of continental and arc terranes during the Mesozoic and early Tertiary. The Jinsha and Banggong Sutures in Tibet join continental terranes separated from Gondwana. Ophiolites were obducted onto the shelf of southern Tibet in the Jurassic before the formation of the Banggong Suture. The Kohistan—Ladakh Terrane contains an island arc that was accreted in the late Cretaceous on the Shyok Suture and consequently evolved into an Andean-type batholith. Further east this TransHimalayan batholith developed on the southern active margin of Tibet without the prior development of an island arc. Ophiolites were obducted onto the shelf of India in the late Cretaceous to Lower Palaeocene before the closing of Tethys and the formation of the Indus—Yarlung Zangbo Suture at about 50 Ma. Post-collisional northward indentation of India at ca.5 cm a-1 since the Eocene has redeformed this accreted terrane collage; palaeomagnetic evidence suggests this indentation has given rise to some 2000 km of intracontinental shortening. Expressions of this shortening are the uplift of mid-crustal gneisses in the Karakoram on a late-Tertiary breakback thrust, folding of Palaeogene redbeds in Tibet, south-directed thrust imbrication of the foreland and shelf of the Indian Plate, north-directed back-thrusts along the Indus Suture Zone, post-Miocene spreading and uplift of thickened Tibet, giving rise to N—S extensional faults, and strike-slip faults, which allowed eastward escape of Tibetan fault blocks.


2020 ◽  
Vol 408 ◽  
pp. 105718
Author(s):  
Alastair H.F. Robertson ◽  
Osman Palak ◽  
Kemal Taslı ◽  
Paulian Dumitrica

1983 ◽  
Vol 73 (4) ◽  
pp. 205-219 ◽  
Author(s):  
M. P. Searle

ABSTRACTThe Tibetan–Tethys zone of the Zanskar Himalaya shows a complete Mesozoic shelf carbonate sequence overlying metamorphic basement of the Central crystalline complex and Palaeozoic sedimentary rocks. Continental rifting in the Permian produced the alkaline and basaltic Panjal volcanic rocks and by Triassic time a small ocean basin was developed in the Indus-Tsangpo zone. Stable sedimentation continued until the Middle-Late Cretaceous when a thick sequence of tholeiitic to andesitic island arc lavas (Dras arc) were erupted in the basin above a N-dipping subduction zone. The Spontang ophiolite was emplaced southwards onto the Zanskar shelf edge during latest Cretaceous or earliest Tertiary times.Following emplacement of the Spontang ophiolite, deep-sea sedimentation ended abruptly with initial collision between the Indian plate and the Dras island arc. Emplacement of the massive Ladakh (Trans-Himalayan) batholith along the southern margin of Tibet in late Cretaceous-Eocene time occurred by crustal melting as a result of northward subduction of Mesozoic oceanic crust along the Indus subduction zone. Southward-directed thrusting in both Zanskar and Indus zones accompanied ocean closure during the late Cretaceous–Eocene. Late Tertiary compression caused intense folding, overturning and a phase of northward-directed thrusting along the Indus suture zone and the northern margin of the Tibetan–Tethys zone, resulting in a large amount of crustal shortening.


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