The Indian Plate or India Plate is a major tectonic plate straddling the
equator in the eastern hemisphere. Originally a part of the ancient
continent of Gondwana, India broke away from the other fragments of Gondwana 100
million years ago and began moving north. Once fused with the adjacent
Australia to form a single Indo-Australian Plate, recent studies
suggest that India and Australia have been separate plates for at least 3
million years and likely longer. The Indian plate includes most of South
Asia—i.e. the Indian subcontinent—and a portion of the basin under the Indian
Ocean, including parts of South China and Eastern Indonesia, and extending up
to but not including Ladakh, Kohistan and Balochistan.
Plate movements Until roughly 140 million years ago, the
Indian Plate formed part of the supercontinent Gondwana together with
modern Africa, Australia, Antarctica, and South America. Gondwana broke up as
these continents drifted apart at different velocities, a process which
led to the opening of the Indian Ocean. In the late Cretaceous, approximately
100 million years ago and subsequent to the splitting off from Gondwana of
conjoined Madagascar and India, the Indian Plate split from Madagascar. It
began moving north, at about 20 centimetres per year, and is believed to
have begun colliding with Asia as early as 55 million years ago, in the Eocene
epoch of the Cenozoic. However, some authors suggest that the collision
between India and Eurasia occurred much later, around 35 million years ago. If
the collision occurred between 55 and 50 Mya, the Indian Plate would have covered
a distance of 3,000 to 2,000 kilometres, moving faster than any other known
plate. In 2012, paleomagnetic data from the Greater Himalaya was used to propose
two collisions to reconcile the discrepancy between the amount of
crustal shortening in the Himalaya and the amount of convergence between India
and Asia. These authors propose a continental fragment of northern
Gondwana rifted from India, traveled northward, and initiated the "soft
collision" between the Greater Himalaya and Asia at ~50 Ma. This was followed by
the "hard collision" between India and Asia occurred at ~25 Ma. Subduction of
the resulting ocean basin that formed between the Greater Himalayan fragment
and India explains the apparent discrepancy between the crustal
shortening estimates in the Himalaya and paleomagnetic data from India and Asia.
In 2007, German geologists suggested that the reason the Indian Plate moved
so quickly is that it is only half as thick as the other plates which formerly
constituted Gondwana. The mantle plume that once broke up Gondwana might also
have melted the lower part of the Indian subcontinent, which allowed it to move
both faster and further than the other parts. The remains of this plume today
form the Marion, Kerguelen, and Réunion hotspots. As India moved north, it is
possible that the thickness of the Indian plate degenerated further as it
passed over the hotspots and magmatic extrusions associated with the Deccan
and Rajmahal Traps. The massive amounts of volcanic gases released during the
passage of the Indian Plate over the hotspots have been theorised to have
played a role in the Cretaceous–Paleogene extinction event,
generally held to be due to a large asteroid impact.
The collision with the Eurasian Plate along the boundary between India and
Nepal formed the orogenic belt that created the Tibetan Plateau and the
Himalaya Mountains, as sediment bunched up like earth before a plow.
The Indian Plate is currently moving north-east at 5 centimetres per year,
while the Eurasian Plate is moving north at only 2 centimetres per year. This is
causing the Eurasian Plate to deform, and the Indian Plate to compress at a
rate of 4 millimetres per year. Geography
The westerly side of the Indian Plate is a transform boundary with the Arabian
Plate called the Owen Fracture Zone, and a divergent boundary with the African
Plate called the Central Indian Ridge. The northerly side of the Plate is a
convergent boundary with the Eurasian Plate forming the Himalaya and Hindu
Kush mountains. See also
Convergent boundary List of tectonic plates
List of tectonic plate interactions Paleogeography
Notes References