The document summarizes the evolution of the Tethys Ocean and the collision of the Indian and Eurasian plates. It describes how the Tethys Ocean separated the supercontinent Pangaea into Laurasia and Gondwana starting 290 million years ago. As Gondwana split apart over the next 100 million years, the Indian plate separated from East Gondwana and moved rapidly northward, closing the Tethys Ocean. The collision of India with Eurasia began between 70-25 million years ago, producing the Himalayan mountain range and significantly changing the Earth's surface geography.

1. Evolution of Tethys Ocean and
Collision of INDIAN PLATE WITH
EURASIAN PLATE
By Mukhtiar Ghani
mukhtiarghani@upesh.edu.pk

2. Introduction
 The collision of Indian and Eurasian plates has significantly changed the
surface of the earth
 Producing one of the most spectacular orogenic mountain ranges called the
Himalayas.
 Contains some of the highest mountains on earth.
 Triggering ice ages.

3. Evolution of Tethys Ocean
A super continent Pangea was formed about 300 My ago
It existed during late Paleozoic and early Mesozoic era
Covering much of the southern hemisphere unlike today
Pangea had two distinct divisions i.e. Laurasia and Gondwanaland
The Pangea was surrounded by a super ocean called Panthalassa
Smaller ocean called paleo Tethys ocean occupied an area between Laurasia
and Gondwanaland
It was narrow in the west and extremely wide in the east forming a gulf

4. 290 Ma

5. The India-Asia collision is a part of a long accretion history of small
sized microcontinents
Originated from the break-up of Gondwanaland in the Paleozoic
(Bond et al., 1984).
progressively accreted from then on
contributed to the growth of the Asian margin southwards (Matte et
al., 1996).
These were accreted in three episodes:
(1) Variscan
(2) Cimmerian
(3) Alpine

6. The Cimmerian episode corresponds to the break-up of the
Cimmerian continent from the Gondwana margin.
Began in the Late Permian and was complete during the Triassic
(Sengör et al., 1988).
The closure of the Paleo-Tethys Ocean, and saturation of the
Cimmerian Continents occurred between Middle Triassic (Zanchi et
al., 2000).
Panjal trap volcanism and Peshawar plain alkaline igneous complex
are associated with opening of the Neo-Tethys Ocean (Honnegger et
al., 1982).

7. 250 Ma

8. The Kohistan Ladakh terrain is characterized by intra oceanic arc
magmatic rocks,
Formed during Middle Cretaceous times (110 to 90 Ma)(Honegger
et al.)
These oceanic terrains are mainly remnants of arc-series reflecting
intra-oceanic subduction of the Neo-Tethys in the north.
The central part of the Karakoram terrain is comprised of the NW-
SE striking composite calc-alkaline Karakoram Batholith
Emplaced between 120 and 88 Ma in response to northwards
subduction of Tethyan oceanic crust (Debon et al., 1987)
These terrains were subsequently accreted to the Asian margin
during the Late Cretaceous (80 to 88 Ma)(Weinberg et al., 2000),
along the Shyok suture zone.

9. Gondwanaland split into two parts at about 210 Ma i.e. East
Gondwana and West Gondwana.
The Indian plate became a part of East Gondwana together with
Australia and Antarctica
In early cretaceous at about 130 million years ago India separated
from the other continents
Started rapid movement towards north covering a distance of 6000
km.
This happened because of formation of Indian ocean in the south
due to rifting
Ocean-ocean subduction in the northern margin of Tethys.
Finally the Tethys Ocean closed and India collided with Eurasia.

10. 100 Ma

12. Collisional Events
The exact time of collision of India with Eurasia is always debated
Estimated to have happened in range of 70 to 25 Ma.
Since 55 million years ago, India has steadily rotated counterclockwise
Coupled with Arabia's separation from Africa about 20 million years ago.
This rotation caused convergence in Baluchistan, closure of some of the
smaller basins (Seistan, Katawaz), collision of various crustal blocks in
Iran-Afghanistan region and formation of the Baluchistan fold-and-thrust
belt.
The India-Eurasia collision produced the spectacular Himalayas along
uplifted and deformed 2,500 km long Indo-Pakistan plate margin.

13. *Between 65 and 55 Ma, the Kohistan Ladakh Arcs were obducted
onto the Indian margin along the Main Mantle Thrust (MMT,
Tahirkheli et al., 1979).
*Magnetic studies have evidenced an abrupt decrease in
convergence rate, from 18-19.5 cm.y-1 to 4.5 cm.y-1, at ~ 50 Ma for
Patriat & Achache (1984)
*This drop in convergence rate coincides with a reduction in the
spreading rate of SW and central Mid-Indian Ocean ridge at 56 – 50
Ma (Molnar & Tapponnier, 1975)

14. The timing of the collision is constrained by extensive emplacement of
ophiolites along the Indus- Tsango Suture Zone, in Waziristan, Zhob
Valley and Lasbela area.
Along suture zones the youngest marine sediments are lower Eocene.
At places Indus molasse overlies Early Eocene limestone and contains
debris both of Eurasian and Indian terrains.
Compressional tectonic began after deposition of Early Eocene
Nummulitic limestone.

15. Thanks