Formation of the plates and regional geology
Formation of the Plates
Although significant advances have been made in the last 40 years since the acceptance of plate tectonics, many parts of Asia's tectonic history remain poorly understood. By utilizing paleomagnetic and paleontological evidence, numerous reconstructions have been proposed. Most scientists agree on the overall relative motions of the major Asian plates, however many other details remain inconclusive.
There have been dramatic changes in the configuration of the Asian plates throughout history. For example, during the Eocene, the northern part of the Philippine Sea Plate was located near the equator. This preceded a period of 25 Ma, at which point it underwent a clockwise 90° rotation and began moving northward. By 15 Ma ago, the northward shift of the Philippine Sea Plate had all but come to a stop, and rotation had ceased (Yamazaki et al, 2010). The standing theory is that the Okhotsk plate travelled northward with the Kula plate until it reached Eurasia some 80 Ma. Upon collision, it in effect blocked the subduction zone between the Kula and Eurasian plates (Bogdanov and Dobretsov 2002). As the Indian Plate drifted northwards, it rotated and collided with Eurasia at an oblique angle, and transform forces along the newly created subduction front caused the bending of the Sunda arc. Consequently, in the Oligocene, further faulting developed, and the Burma and Sunda plates began to break off from Eurasia (Zahran et al, 2007).
There have been dramatic changes in the configuration of the Asian plates throughout history. For example, during the Eocene, the northern part of the Philippine Sea Plate was located near the equator. This preceded a period of 25 Ma, at which point it underwent a clockwise 90° rotation and began moving northward. By 15 Ma ago, the northward shift of the Philippine Sea Plate had all but come to a stop, and rotation had ceased (Yamazaki et al, 2010). The standing theory is that the Okhotsk plate travelled northward with the Kula plate until it reached Eurasia some 80 Ma. Upon collision, it in effect blocked the subduction zone between the Kula and Eurasian plates (Bogdanov and Dobretsov 2002). As the Indian Plate drifted northwards, it rotated and collided with Eurasia at an oblique angle, and transform forces along the newly created subduction front caused the bending of the Sunda arc. Consequently, in the Oligocene, further faulting developed, and the Burma and Sunda plates began to break off from Eurasia (Zahran et al, 2007).
Geologic Setting
The tectonic plates of Asia show a vast range of geological settings. The plates are dominated by relatively simple oceanic crust, with strikingly complex continental geology.
Approximately 80-90 Ma old, the Okhotsk-Chukotka Volcanic Belt has received a great deal of attention from geologists and represents one of the world's largest volume ignimbrite "flare-ups" in a continental arc setting. Its eruptions have scattered ash all the way to Alaska (Stanford). The Okhotsk Plate is interpreted to represent an old oceanic flood basalt plateau. Seismic surveys have shown that the Okhotsk Sea Plate is composed of three layers: gabbroic cumulates, interbedded volcanics, sills and sediments, and sedimentary fill. Kamchatka and the Kuril islands represent a volcanic arc composed of basalts, andesites, dacites, and rhyolites (Konstantinovskaia, 2001).
The geology of Burma is poorly known. Political unrest makes it difficult to study the area, and although petroleum geologists have investigated the Tertiary geology of Burma for decades, most of this information cannot be made public. The Andaman and Nicobar archipelago are part of an accretionary wedge, formed by the oblique subduction of the Indian plate below the Burma microplate at a rate of 4-6 cm per year (Curray, 2005).
The Mariana Islands are formed of volcanic and Pleistocene-age calcareous sedimentary rocks. Considering their age (170 Ma), oceanic sediments being delivered to the Izu-Bonin-Mariana trench are thin. Away from seamounts chert and pelagic clay dominate, but near isolated seamounts called guyots, carbonates play an important role. Interestingly, the compositions of sediments being subducted beneath the northern and southern parts of the IBM arc are significantly different. This can be explained by the Cretaceous off-ridge volcanic succession present in the south, which is missing in the north.
The Philippine Sea Plate has incredibly thick oceanic crust, over five times the average 6km. The crust is of varying thickness; it ranges from 29-41 km along the Nankai trough. Deep sea drilling studies have also shown that the West Pacific Sea Basin is older than the East PSB, dating back to the Eocene (Fang, 2011).
The Sunda Plate formed from the same process as the Burma microplate: by tearing off of the Eurasian plate during the Oligocene. The Sunda Shelf, a broad shallow sea contained in the Sunda plate, was exposed land during the Pleistocene glacial lowstands. Today, outcrops dating to pre-Tertiary times are largely visible.
Approximately 80-90 Ma old, the Okhotsk-Chukotka Volcanic Belt has received a great deal of attention from geologists and represents one of the world's largest volume ignimbrite "flare-ups" in a continental arc setting. Its eruptions have scattered ash all the way to Alaska (Stanford). The Okhotsk Plate is interpreted to represent an old oceanic flood basalt plateau. Seismic surveys have shown that the Okhotsk Sea Plate is composed of three layers: gabbroic cumulates, interbedded volcanics, sills and sediments, and sedimentary fill. Kamchatka and the Kuril islands represent a volcanic arc composed of basalts, andesites, dacites, and rhyolites (Konstantinovskaia, 2001).
The geology of Burma is poorly known. Political unrest makes it difficult to study the area, and although petroleum geologists have investigated the Tertiary geology of Burma for decades, most of this information cannot be made public. The Andaman and Nicobar archipelago are part of an accretionary wedge, formed by the oblique subduction of the Indian plate below the Burma microplate at a rate of 4-6 cm per year (Curray, 2005).
The Mariana Islands are formed of volcanic and Pleistocene-age calcareous sedimentary rocks. Considering their age (170 Ma), oceanic sediments being delivered to the Izu-Bonin-Mariana trench are thin. Away from seamounts chert and pelagic clay dominate, but near isolated seamounts called guyots, carbonates play an important role. Interestingly, the compositions of sediments being subducted beneath the northern and southern parts of the IBM arc are significantly different. This can be explained by the Cretaceous off-ridge volcanic succession present in the south, which is missing in the north.
The Philippine Sea Plate has incredibly thick oceanic crust, over five times the average 6km. The crust is of varying thickness; it ranges from 29-41 km along the Nankai trough. Deep sea drilling studies have also shown that the West Pacific Sea Basin is older than the East PSB, dating back to the Eocene (Fang, 2011).
The Sunda Plate formed from the same process as the Burma microplate: by tearing off of the Eurasian plate during the Oligocene. The Sunda Shelf, a broad shallow sea contained in the Sunda plate, was exposed land during the Pleistocene glacial lowstands. Today, outcrops dating to pre-Tertiary times are largely visible.
Formation of the Himalayas
The collision of the Indian plate into Eurasia about 50 Ma was perhaps the most significant tectonic event to affect Asia since the breakup of Gondwanaland 70 million years beforehand. The collision resulted in the erection of the Tibetan plateau and the highest mountain chain on Earth today: the Himalayas (National Geographic). The collision also resulted in the creation of numerous small plates to the eastern boundary of the Indian plate. Although the relative motion of the plate has slowed to 3 cm per year, the movement of the Indian plate continues to put enormous pressure on the Asian continent. The tectonic forces at play in this region act to squeeze parts of Asia eastward toward the Pacific Ocean, and consequently enormous stresses build up (USGS). These stresses must be relieved periodically by earthquakes along the numerous faults that scar the landscape.
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The region studied spans too large an area with a complex history to examine the geologic history of the Asian plates in depth. Additional information can be found at the links below:
Mariana's Trench:
National Geographic: http://deepseachallenge.com/the-science/geology/
The Philippine Sea:
USGS: http://dx.doi.org/10.3133/ofr20101083m
The Himalayas:
USGS: http://pubs.usgs.gov/gip/dynamic/himalaya.html
The History Channel:
http://www.history.com/topics/himalayas
The Sunda Plate:
Bibliography of the geology of Indonesia and surrounding areas: http://www.vangorselslist.com/sundaland.html
The Burma Plate:
USGS: http://pubs.usgs.gov/bul/2208/E/pdf/B2208-E.pdf
Mariana's Trench:
National Geographic: http://deepseachallenge.com/the-science/geology/
The Philippine Sea:
USGS: http://dx.doi.org/10.3133/ofr20101083m
The Himalayas:
USGS: http://pubs.usgs.gov/gip/dynamic/himalaya.html
The History Channel:
http://www.history.com/topics/himalayas
The Sunda Plate:
Bibliography of the geology of Indonesia and surrounding areas: http://www.vangorselslist.com/sundaland.html
The Burma Plate:
USGS: http://pubs.usgs.gov/bul/2208/E/pdf/B2208-E.pdf
References
Bogdanov, N.A. and Dobretsov, N.L. (2002) The Okhotsk volcanic plateau, Russian Geology and Geophysics, 43, 87-99.
Curray, J.R. (2005) Tectonics and History of the Andaman Sea Region. Journal of Asian Earth Sciences vol. 25(1), 187-232.
Derbeko, I.M. (2012). The Role of the Andesitic Volcanism in the Understanding of Late Mesozoic Tectonic Events of Bureya-Jziamysi Superterrain, Russian Far East, Updates in Volcanology - New Advances in Understanding Volcanic Systems, Dr. Karoly Nemeth (Ed.), ISBN: 978-953-51-0915-0, InTech, DOI: 10.5772/51908.
Fang et al. (2009). The formation and tectonic evolution of Philippine Sea Plate and KPR, Acta Oceanol. Vol 30(4), 75-88
Hall, R., Ali, J. R., Anderson, C. D., & Baker, S. J. (1995). Origin and Motion History of the Philippine Sea Plate. Tectonophysics, 251(1–4), 229-250.
Jin, Shuanggen, Pil-Ho Park, and Wenyao Zhu. (2007) Micro-plate tectonics and kinematics in Northeast Asia inferred from a dense set of GPS observations. Earth and Planetary Science Letters 257(3), 486-496.
Konstantinovskaia, E. A. (2001) Arc–continent collision and subduction reversal in the Cenozoic evolution of the Northwest Pacific: an example from Kamchatka (NE Russia)." Tectonophysics 333(1), 75-94.
National Geographic Dea Sea Challenge, Geology, http://deepseachallenge.com/the-science/geology/. Retrieved January 30, 2014.
Savostin, L., Zonenshain, L. and Baranov, B. (2013) Geology and Plate Tectonics of the Sea of Okhotsk, in Geodynamics of the Western Pacific-Indonesian Region (eds T. W.C. Hilde and S. Uyeda), American Geophysical Union, Washington, D. C.. doi: 10.1029/GD011p0189.
Smoczyk, G.M., Hayes, G.P., Hamburger, M.W., Benz, H.M., Villaseñor, Antonio, and Furlong, K.P., 2013, Seismicity of the Earth 1900–2012 Philippine Sea Plate and vicinity: U.S. Geological Survey Open-File Report 2010–1083-M, scale 1:10,000,000.
"Magmatic Belts of Northeast Russia." Stanford Structural Geology and Tectonics. Retrieved 30 Jan. 2014.
The History Channel, " Himalayas". http://www.history.com/topics/himalayas. Retrieved January 30, 2014.
USGS Tectonic Summary http://pubs.usgs.gov/gip/dynamic/himalaya.html. Retrieved January 29, 2014.
Wandrey, C.J., 2006, Eocene to Miocene Composite Total Petroleum System, Irrawaddy-Andaman and North Burma Geologic Provinces, Myanmar, Chapter E in Wandrey, C.J., ed., Petroleum systems and related geologic studies in Region 8, South Asia: U.S. Geological Survey Bulletin 2208-E, 26 p.
Yamazaki, T. et al. (2010) "Philippine Sea Plate motion since the Eocene estimated from paleomagnetism of seafloor drill cores and gravity cores." Earth Planets Space 62: pp. 495–502.
Zahran, K.H., Khalil H., Saleh, S. and I. Selim. (2007) "Tidal Stress Triggering Earthquakes: Case Study The Eastern Part of the Indian Ocean." MESF Cyber Journal of Geoscience 5: pp. 1-21
Curray, J.R. (2005) Tectonics and History of the Andaman Sea Region. Journal of Asian Earth Sciences vol. 25(1), 187-232.
Derbeko, I.M. (2012). The Role of the Andesitic Volcanism in the Understanding of Late Mesozoic Tectonic Events of Bureya-Jziamysi Superterrain, Russian Far East, Updates in Volcanology - New Advances in Understanding Volcanic Systems, Dr. Karoly Nemeth (Ed.), ISBN: 978-953-51-0915-0, InTech, DOI: 10.5772/51908.
Fang et al. (2009). The formation and tectonic evolution of Philippine Sea Plate and KPR, Acta Oceanol. Vol 30(4), 75-88
Hall, R., Ali, J. R., Anderson, C. D., & Baker, S. J. (1995). Origin and Motion History of the Philippine Sea Plate. Tectonophysics, 251(1–4), 229-250.
Jin, Shuanggen, Pil-Ho Park, and Wenyao Zhu. (2007) Micro-plate tectonics and kinematics in Northeast Asia inferred from a dense set of GPS observations. Earth and Planetary Science Letters 257(3), 486-496.
Konstantinovskaia, E. A. (2001) Arc–continent collision and subduction reversal in the Cenozoic evolution of the Northwest Pacific: an example from Kamchatka (NE Russia)." Tectonophysics 333(1), 75-94.
National Geographic Dea Sea Challenge, Geology, http://deepseachallenge.com/the-science/geology/. Retrieved January 30, 2014.
Savostin, L., Zonenshain, L. and Baranov, B. (2013) Geology and Plate Tectonics of the Sea of Okhotsk, in Geodynamics of the Western Pacific-Indonesian Region (eds T. W.C. Hilde and S. Uyeda), American Geophysical Union, Washington, D. C.. doi: 10.1029/GD011p0189.
Smoczyk, G.M., Hayes, G.P., Hamburger, M.W., Benz, H.M., Villaseñor, Antonio, and Furlong, K.P., 2013, Seismicity of the Earth 1900–2012 Philippine Sea Plate and vicinity: U.S. Geological Survey Open-File Report 2010–1083-M, scale 1:10,000,000.
"Magmatic Belts of Northeast Russia." Stanford Structural Geology and Tectonics. Retrieved 30 Jan. 2014.
The History Channel, " Himalayas". http://www.history.com/topics/himalayas. Retrieved January 30, 2014.
USGS Tectonic Summary http://pubs.usgs.gov/gip/dynamic/himalaya.html. Retrieved January 29, 2014.
Wandrey, C.J., 2006, Eocene to Miocene Composite Total Petroleum System, Irrawaddy-Andaman and North Burma Geologic Provinces, Myanmar, Chapter E in Wandrey, C.J., ed., Petroleum systems and related geologic studies in Region 8, South Asia: U.S. Geological Survey Bulletin 2208-E, 26 p.
Yamazaki, T. et al. (2010) "Philippine Sea Plate motion since the Eocene estimated from paleomagnetism of seafloor drill cores and gravity cores." Earth Planets Space 62: pp. 495–502.
Zahran, K.H., Khalil H., Saleh, S. and I. Selim. (2007) "Tidal Stress Triggering Earthquakes: Case Study The Eastern Part of the Indian Ocean." MESF Cyber Journal of Geoscience 5: pp. 1-21
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