Indian Plate
My Blogs (olelog) are mainly based on my daily
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Indian Plate |
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My Blogs (olelog) are mainly based on my daily
reading of earth science news.
Here on whatonearth.olehnielsen.dk I try to weave
some of the pieces together to a greater whole with added background info.
|
||
The Indo-Australian Plate — long identified as a single plate on which both India and Australia lie — appears to have broken apart just south of the Equator beneath the Indian Ocean. The break has been underway for the past several million years, and now the two continents are moving independently of one another in slightly different directions.
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 India Plate is currently moving northeast at 5 cm/yr (2 in/yr), while the Eurasian Plate is moving north at only 2 cm/yr (0.8 in/yr). This is causing the Eurasian Plate to deform, and the India Plate to compress at a rate of 4 mm/yr (0.15 in/yr).
← Image from USGS
About 225 million years ago, India was a large island still situated off the
Australian coast, and a vast ocean (called Tethys Sea) separated India from
the Asian continent. When Pangaea broke apart about 200 million years ago, India
began to forge northward.
About 90 million years ago, in the late Cretaceous Period, the India Plate split from Madagascar off the east coast of Africa. It began moving north, at about 15 cm/yr (6 in/yr), and began colliding with Asia between 50 and 55 million years ago, in the Eocene epoch of the Cenozoic Era. During this time, the India Plate covered a distance of 2,000 to 3,000 km (1,200 to 1,900 mi), and moved faster than any other known plate.
About 80 million years ago, India was located roughly 6,400 km south of the Asian continent, moving northward at a rate of about 9 m a century. When India rammed into Asia about 40 to 50 million years ago, its northward advance slowed by about half. The collision and associated decrease in the rate of plate movement are interpreted to mark the beginning of the rapid uplift of the Himalayas.
Note the anticlockwise rotation of India from 71 to 10 million years ago.
At around 38 million years ago, at the Eocene-Oligocene boundary, the rate and direction of convergence changed abruptly. Before 38 million years ago the convergence rate was between 10 and 18 cm/year in a NNE direction. After 30 million years ago it slowed to about 5 cm/year in a nortward direction.
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