The Indo-Australian Plate is a major tectonic plate that included the continent of Australia and the surrounding ocean and extended north-west to include the Indian subcontinent and the adjacent waters. It was formed by the fusion of the Indian and the Australian plates approximately 43 million years ago.[1] The fusion happened when the mid-ocean ridge in the Indian Ocean, which separated the two plates, ceased spreading.[2] Contemporary models suggest at present there is a deformation zone between the Indian and Australian Plates with both earthquake and global satellite navigation system data indicating that India and Australia are not moving on the same vectors northward.[3][4] These observations are consistent with earlier evidence that the Indian Plate and Australian Plate have been acting as separate plates for at least the last 3 million years.[5] In due course some expect a localized boundary to reform between the Indian and Australian plates.[6]
In red and orange is the Indo-Australian Plate, shown as divided between the Indian Plate and the Australian Plate
The eastern side of the plate is the convergent boundary with the Pacific plate. The Pacific plate sinks below the Australian plate and forms the Kermadec Trench and the island arcs of Tonga and Kermadec. New Zealand is situated along the southeastern boundary of the plate, which with New Caledonia make up the southern and northern ends of the ancient landmass of Zealandia, which separated from Australia 85 million years ago. The central part of Zealandia sank under the sea.
The southern margin of the plate forms a divergent boundary with the Antarctic plate. The western side is subdivided by the Indian plate that borders the Arabian plate to the north and the African plate to the south. The northern margin of the Hindustani plate forms a convergent boundary with the Eurasian plate, which constitutes the active orogenic process of the Himalayas and the Hindukush mountains.
The northeast side of the Australian plate forms a subduction boundary with the Eurasian plate in the Indian Ocean and between the borders of Bangladesh and Burma, and to the southwest of the Indonesian islands of Sumatra and Borneo. Along the northern NinetyEast Ridge under the Indian Ocean there appears to be a weakness zone where the Indian and Australian Plates are going different ways.[3][4] The subsidence boundary through Indonesia is reflected in the Wallace line.
Plate movementsedit
The eastern part (Australian Plate) is moving northward at the rate of 5.6 cm (2.2 in) per year while the western part (Indian Plate) is moving only at the rate of 3.7 cm (1.5 in) per year due to the impediment of the Himalayas. In terms of the middle of India and Australia landmasses, Australia is moving northward at 3 cm (1.2 in) per year with respect to India.[3] This differential movement has resulted in the compression of the former plate near its centre at Sumatra and the division into the separate Indian and Australian Plates again.[7][4]
A third plate, known as the Capricorn Plate, may also be separating off the western side of the Indian plate as part of the continued breakup of the Indo-Australian Plate.[8]
Separationedit
Recent studies, and evidence from seismic events such as the 2012 Indian Ocean earthquakes, suggest that the Indo-Australian Plate may have broken up into two or three separate plates due primarily to stresses induced by the collision of the Indo-Australian Plate with Eurasia along what later became the Himalayas,[9][10] and that the Indian Plate and Australian Plate may have been separate since at least 3 million years ago.[5]
^Keep, Myra; Schellart, Wouter P. (2012). "Introduction to the thematic issue on the evolution and dynamics of the Indo-Australian plate". Australian Journal of Earth Sciences. 59, 2012 (6: THEMATIC ISSUE — Evolution and dynamics of the Indo-Australian plate): 807–808. Bibcode:2012AuJES..59..807K. doi:10.1080/08120099.2012.708360. S2CID 128996831.
^ abcdDelescluse, Matthias; Chamot-Rooke, Nicolas (2007). "Instantaneous deformation and kinematics of the India–Australia Plate". Geophysical Journal International. 168 (2): 818–842. doi:10.1111/j.1365-246X.2006.03181.x.
^ abcdDelescluse, Matthias; Chamot-Rooke, Nicolas; Cattin, Rodolphe; Fleitout, Luce; Trubienko, Olga; Vigny, Christophe (26 September 2012). "April 2012 intra-oceanic seismicity off Sumatra boosted by the Banda-Aceh megathrust". Nature. 490 (7419): 240–4. Bibcode:2012Natur.490..240D. doi:10.1038/nature11520. PMID 23023134. S2CID 205230868.
^ abcStein, Seth; Sella, Giovanni; Okai, Emile A. (2002). "The January 26, 2001 Bhuj Earthquake and the Diffuse Western Boundary of the Indian Plate" (PDF). Plate Boundary Zones. Geodynamics Series. American Geophysical Union. pp. 243–254. doi:10.1029/GD030p0243. ISBN9781118670446. Retrieved 26 December 2015.
^ abYue, H.; Lay, T.; Koper, K. (2012). "En échelon and orthogonal fault ruptures of the 11 April 2012 great intraplate earthquakes". Nature. 490: 245–249. doi:10.1038/nature11492.
^"Earth cracking up under Indian Ocean". New Scientist. 26 September 2012. Retrieved 14 March 2018.
^Siegel, Lee (26 September 2012). "Sumatra quake was part of crustal plate breakup: Study shows huge jolt measured 8.7, ripped at least 4 faults". Phys.Org. Retrieved 6 October 2012.
^"Press Release: An Earth Plate Is Breaking in Two". www.columbia.edu.
^R. R. Hillis, R. D. Müller. Evolution and Dynamics of the Australian Plate
February 16, 2024
indo, australian, plate, major, tectonic, plate, that, included, continent, australia, surrounding, ocean, extended, north, west, include, indian, subcontinent, adjacent, waters, formed, fusion, indian, australian, plates, approximately, million, years, fusion. The Indo Australian Plate is a major tectonic plate that included the continent of Australia and the surrounding ocean and extended north west to include the Indian subcontinent and the adjacent waters It was formed by the fusion of the Indian and the Australian plates approximately 43 million years ago 1 The fusion happened when the mid ocean ridge in the Indian Ocean which separated the two plates ceased spreading 2 Contemporary models suggest at present there is a deformation zone between the Indian and Australian Plates with both earthquake and global satellite navigation system data indicating that India and Australia are not moving on the same vectors northward 3 4 These observations are consistent with earlier evidence that the Indian Plate and Australian Plate have been acting as separate plates for at least the last 3 million years 5 In due course some expect a localized boundary to reform between the Indian and Australian plates 6 In red and orange is the Indo Australian Plate shown as divided between the Indian Plate and the Australian Plate Contents 1 Regions 2 Characteristics 3 Plate movements 3 1 Separation 4 ReferencesRegions editAustralia New Guinea Mainland Australia New Guinea and Tasmania the Indian subcontinent and Zealandia New Caledonia New Zealand and Norfolk Island are all fragments of the ancient supercontinent of Gondwana As the ocean floor broke apart these land masses fragmented from one another and for a time these centers were thought to be dormant and fused into a single plate However research in the early 21st century indicates plate separation of the Indo Australian Plate may have already occurred 5 3 6 4 Characteristics editThe eastern side of the plate is the convergent boundary with the Pacific plate The Pacific plate sinks below the Australian plate and forms the Kermadec Trench and the island arcs of Tonga and Kermadec New Zealand is situated along the southeastern boundary of the plate which with New Caledonia make up the southern and northern ends of the ancient landmass of Zealandia which separated from Australia 85 million years ago The central part of Zealandia sank under the sea The southern margin of the plate forms a divergent boundary with the Antarctic plate The western side is subdivided by the Indian plate that borders the Arabian plate to the north and the African plate to the south The northern margin of the Hindustani plate forms a convergent boundary with the Eurasian plate which constitutes the active orogenic process of the Himalayas and the Hindukush mountains The northeast side of the Australian plate forms a subduction boundary with the Eurasian plate in the Indian Ocean and between the borders of Bangladesh and Burma and to the southwest of the Indonesian islands of Sumatra and Borneo Along the northern NinetyEast Ridge under the Indian Ocean there appears to be a weakness zone where the Indian and Australian Plates are going different ways 3 4 The subsidence boundary through Indonesia is reflected in the Wallace line Plate movements editThe eastern part Australian Plate is moving northward at the rate of 5 6 cm 2 2 in per year while the western part Indian Plate is moving only at the rate of 3 7 cm 1 5 in per year due to the impediment of the Himalayas In terms of the middle of India and Australia landmasses Australia is moving northward at 3 cm 1 2 in per year with respect to India 3 This differential movement has resulted in the compression of the former plate near its centre at Sumatra and the division into the separate Indian and Australian Plates again 7 4 A third plate known as the Capricorn Plate may also be separating off the western side of the Indian plate as part of the continued breakup of the Indo Australian Plate 8 Separation edit Recent studies and evidence from seismic events such as the 2012 Indian Ocean earthquakes suggest that the Indo Australian Plate may have broken up into two or three separate plates due primarily to stresses induced by the collision of the Indo Australian Plate with Eurasia along what later became the Himalayas 9 10 and that the Indian Plate and Australian Plate may have been separate since at least 3 million years ago 5 References edit The Indo Australian Plate austhrutime com Keep Myra Schellart Wouter P 2012 Introduction to the thematic issue on the evolution and dynamics of the Indo Australian plate Australian Journal of Earth Sciences 59 2012 6 THEMATIC ISSUE Evolution and dynamics of the Indo Australian plate 807 808 Bibcode 2012AuJES 59 807K doi 10 1080 08120099 2012 708360 S2CID 128996831 a b c d Delescluse Matthias Chamot Rooke Nicolas 2007 Instantaneous deformation and kinematics of the India Australia Plate Geophysical Journal International 168 2 818 842 doi 10 1111 j 1365 246X 2006 03181 x a b c d Delescluse Matthias Chamot Rooke Nicolas Cattin Rodolphe Fleitout Luce Trubienko Olga Vigny Christophe 26 September 2012 April 2012 intra oceanic seismicity off Sumatra boosted by the Banda Aceh megathrust Nature 490 7419 240 4 Bibcode 2012Natur 490 240D doi 10 1038 nature11520 PMID 23023134 S2CID 205230868 a b c Stein Seth Sella Giovanni Okai Emile A 2002 The January 26 2001 Bhuj Earthquake and the Diffuse Western Boundary of the Indian Plate PDF Plate Boundary Zones Geodynamics Series American Geophysical Union pp 243 254 doi 10 1029 GD030p0243 ISBN 9781118670446 Retrieved 26 December 2015 a b Yue H Lay T Koper K 2012 En echelon and orthogonal fault ruptures of the 11 April 2012 great intraplate earthquakes Nature 490 245 249 doi 10 1038 nature11492 Earth cracking up under Indian Ocean New Scientist 26 September 2012 Retrieved 14 March 2018 Siegel Lee 26 September 2012 Sumatra quake was part of crustal plate breakup Study shows huge jolt measured 8 7 ripped at least 4 faults Phys Org Retrieved 6 October 2012 Press Release An Earth Plate Is Breaking in Two www columbia edu R R Hillis R D Muller Evolution and Dynamics of the Australian Plate Retrieved from https en wikipedia org w index php title Indo Australian Plate amp oldid 1190184017, wikipedia, wiki, book, books, library,
