Indian Plate
The India Plate or Indian Plate is a tectonic plate that was originally a part of the ancient continent of Gondwanaland from which it split off, eventually becoming a major plate. About 55 to 50 million years ago (contested), it fused with the adjacent Australian Plate. It is today part of the major Indo-Australian Plate, and includes most of South Asia and a portion of the basin under the Indian Ocean, including parts of South China and Eastern Indonesia, [1][2][3] and extending up to but not including Ladakh, Kohistan and Balochistan.[4][5][6]
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[edit] Plate movements
140 million years ago the Indian Plate formed part of the supercontinent Gondwanaland together with modern Africa, Australia, Antarctica, and South America. Gondwanaland broke up as these continents drifted apart with different velocities,[7] a process which lead to the opening of the Indian Ocean.[8]
In the late Cretaceous about 90 million years ago, subsequent to the splitting off from Gondwanaland of conjoined Madagascar and India, the Indian Plate split from Madagascar. It began moving north, at about 20 centimetres (7.9 in) per year,[7] and is believed to have begun colliding with Asia between 55 and 50 million years ago,[9] in the Eocene epoch of the Cenozoic, although this is contested, with some authors suggesting it was much later at around 35 million years ago.[10] If the collision occurred between 55 and 50 Ma, the Indian Plate would have covered a distance of 3,000 to 2,000 kilometres (1,900 to 1,200 mi), moving faster than any other known plate.
In 2007, German geologists[7] suggested that the reason the Indian Plate moved so quickly is that it is only half as thick (100 kilometres (62 mi)) as the other plates[11] which formerly constituted Gondwanaland. The mantle plume that once broke up Gondwanaland might also have melted the lower part of the Indian subcontinent, which allowed it to move both faster and further than the other parts.[7] The remains of this plume today form the Marion, Kerguelen, and Réunion hotspots.[8] 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. [8]
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 (2.0 in) per year, while the Eurasian Plate is moving north at only 2 centimetres (0.79 in) per year. This is causing the Eurasian Plate to deform, and the India Plate to compress at a rate of 4 millimetres (0.16 in) per year.
[edit] Recent events
[edit] 2004 Indian Ocean earthquake
The 9.1-9.3 moment magnitude 2004 Indian Ocean earthquake was caused by the release of stresses built up along the subduction zone where the Indian Plate is sliding under the Burma Plate in the eastern Indian Ocean, at a rate of 6 cm/yr (2.5 in/yr). The Sunda Trench is formed along this boundary where the Indo-Australian and Eurasian Plates meet. Earthquakes in the region are either caused by thrust faulting, where the fault slips at right angles to the trench; or strike-slip faulting, where material to the east of the fault slips along the direction of the trench.
Like all similarly large earthquakes, the December 26, 2004 event was caused by thrust-faulting. A 100 kilometres (62 mi) rupture caused about 1,600 kilometres (990 mi) of the interface to slip, which moved the fault 15 metres (49 ft) and lifted the sea floor several meters (yards), creating the great tsunami.
[edit] 2005 Kashmir earthquake
On October 8, 2005, an earthquake of magnitude 7.6 occurred near Muzaffarabad, Kashmir, Pakistan killing more than 80,000 people, and leaving more than 2.5 million homeless.
[edit] See also
- Convergent boundary
- Geology of India
- List of tectonic plates
- List of tectonic plate interactions
- Paleogeography
[edit] Notes
- ^ Sinvhal, Understanding Earthquake Disasters, page 52, Tata McGraw-Hill Education, 2010, ISBN 9780070144569
- ^ Harsh K. Gupta, Disaster management, page 85, Universities Press, 2003, ISBN 9788173714566
- ^ James R. Heirtzler, Indian ocean geology and biostratigraphy, page American Geophysical Union, 1977, ISBN 9780875902081
- ^ M. Asif Khan, Tectonics of the Nanga Parbat syntaxis and the Western Himalaya, page 375, Geological Society of London, 2000, ISBN 9781862390614
- ^ Srikrishna Prapnnachari, Concepts in Frame Design, page 152, Srikrishna Prapnnachari, ISBN 9789992952214
- ^ A. M. Celâl Şengör, Tectonic evolution of the Tethyan Region, Springer, 1989, ISBN 9780792300670
- ^ a b c d Kind 2007
- ^ a b c Kumar et al. 2007
- ^ Scotese 2001
- ^ Aitchison, Ali & Davis 2007
- ^ The lithospheric roots in South Africa, Australia, and Antarctica are 300 to 180 kilometres (190 to 110 mi) thick. (Kumar et al. 2007) See also Kumar et al. 2007, figure 1,
- ^ Chen 2005
[edit] References
- Aitchison, Jonathan C.; Ali, Jason R.; Davis, Aileen M. (2007). "When and where did India and Asia collide?". Journal of Geophysical Research 112 (B05423). doi:10.1029/2006JB004706. http://perso-sdt.univ-brest.fr/~jacdev/pdf/3a-aitchison07_collision_when_where.pdf. Retrieved January 2012.
- Chen, Ji (January 2005). "Magnitude 9.0 off W coast of northern Sumatra Sunday, December 26, 2004 at 00:58:49 UTC: Preliminary rupture model". U.S. Geological Survey. http://neic.usgs.gov/neis/eq_depot/2004/eq_041226/neic_slav_ff.html. Retrieved December 28, 2004..
- Kind, Rainer (September 2007). "The fastest continent: India's truncated lithospheric roots". Helmholtz Association of German Research Centres. http://www.eurekalert.org/pub_releases/2007-10/haog-tfc101507.php. Retrieved January 2012.
- Kumar, Prakash; Yuan; Kumar, M. Ravi; Kind, Rainer; Li, Xueqing; Chadha, R. K. (18 October 2007). "The rapid drift of the Indian tectonic plate". Nature 449: 894-897. doi:10.1038/nature06214.
- Scotese, Christopher R. (January 2001). "The collision of India and Asia (90 mya — present)". Paleomap Project. http://www.scotese.com/indianim.htm. Retrieved December 28, 2004.
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Coordinates: 34°25′55″N 73°32′13″E / 34.43194°N 73.53694°E
