The Indo-Burman Ranges (IBR), also known as the Indo-Myanmar Ranges,[2][3] is a mountain chain that forms the boundary between the Indian subcontinent and the Indochinese peninsula. This geological feature sits at the convergent boundary of the Indian Plate and the Burma Plate. The Indo-Burman Range merged with Eastern Himalayan Syntaxis further north, submerged into the Andaman Sea, and resurfaced as Andaman Islands further south.[4]
| Indo-Burman Ranges | |
|---|---|
| Indo-Myanmar Ranges | |
 | |
| Highest point | |
| Peak | Mount Saramati[1] |
| Elevation | 3,826 m (12,552 ft) |
| Dimensions | |
| Length | 1,200 km (750 mi) |
| Geography | |
| Countries | |
| States/Regions | |
The mountain belt comprises the following ranges from north to south: the Patkai Bum, the Naga Hills, the Mikir Hills, the Mizo Hills and the Arakan Mountains.[5] The first four are often grouped into the Purvanchal Range, and comprise the northern half of the Indo-Burman mountain system.
Geology
editThe subduction between the Indian Plate and the Burma Plate resulted in the development of accretionary wedges, in order to accommodate the EW shortening along the convergent boundary. Later, thrusting, folding and uplifting formed the Indo-Burman Ranges.[6]
The Indo-Burman Range bulges towards the west at the center (about 22°N), forming an arc-shaped structure.[7] This arc-shaped structure implies restriction on the convergent motion along the Indian-Burma boundary, therefore the collision intensity varies along the range.[5]
The collision is at a maximum at the center of the Indo-Burman Range around 24°N, which is presented with a broad, high range (up to 20 km wide) and evolves to narrow, low hills in the south (16°N).[5] The collision strikes in NW-SE at the northern part of the Indo-Burman Range (Naga Domain).[8]
Lithology
edit
The Indo-Burman Range is a sedimentary belt mainly consisted of Cenozoic flysch sediments[9] and a core of Mesozoic ophiolites dated back to late Jurassic overlain on a thick Mesozoic sequence. All the above unconformity lies on a metamorphic basement dated back to pre-Triassic.[10]
The core Mesozoic ophiolites consists of serpentinite peridotites, pillow basalts and red cherts etc.[10] The obduction of ophiolites is interpreted as the closure of several Neo-Tethys between the Shan-Thai block, Burma microplate and Indian Plate.[7]
The sedimentary sequence overlain by the ophiolites ranges from Late Triassic to Orbitoides-bearing Late Cretaceous carbonates and shales,[7] where part of the sedimentary sequence has undergone high pressure/low temperature blue-schist metamorphism.[9]
The pre-Triassic metamorphic basement composed of Kampetlet schist and gneisses were exposed in the Mount Victoria area in Myanmar.[10] The flysch type sediments in the western flank of the Indo-Burman Range are relatively younger than the folded and thrusted eastern flank.[11]
References
edit- ^ The new encyclopaedia Britannica
- ^ Naing, Tin Tin; Robinson, Stuart A.; Searle, Mike P. (August 2023). "Age, depositional history and tectonics of the Indo-Myanmar Ranges, Myanmar". Journal of the Geological Society. 180. doi:10.1144/jgs2022-091. hdl:2434/970119.
- ^ Ovung, Thungyani N; Ghosh, Biswajit; Rayare, Jyotisankar (15 June 2020). "Petrogenesis of neo-Tethyan ophiolites from the Indo-Myanmar ranges: a review". International Geology Review. doi:10.1080/00206814.2020.1775137.
- ^ Mukhopadhyay, Manoj; Dasgupta, Sujit (1988-06-01). "Deep structure and tectonics of the burmese arc: constraints from earthquake and gravity data". Tectonophysics. 149 (3): 299–322. Bibcode:1988Tectp.149..299M. doi:10.1016/0040-1951(88)90180-1. ISSN 0040-1951. S2CID 129288739.
- ^ a b c Wang, Yu; Sieh, Kerry; Tun, Soe Thura; Lai, Kuang-Yin; Myint, Than (2014-04-01). "Active tectonics and earthquake potential of the Myanmar region". Journal of Geophysical Research: Solid Earth. 119 (4): 2013JB010762. doi:10.1002/2013JB010762. hdl:10220/19774. ISSN 2169-9356.
- ^ Sikder, Arif Mohiuddin; Alam, M.Mustafa (2003). "2-D modelling of the anticlinal structures and structural development of the eastern fold belt of the Bengal Basin, Bangladesh". Sedimentary Geology. 155 (3–4): 209–226. doi:10.1016/s0037-0738(02)00181-1.
- ^ a b c Rangin, Claude; Maurin, Thomas; Masson, Frederic (2013). "Combined effects of Eurasia/Sunda oblique convergence and East-Tibetan crustal flow on the active tectonics of Burma". Journal of Asian Earth Sciences. 76: 185–194. doi:10.1016/j.jseaes.2013.05.018.
- ^ Maurin, Thomas; Rangin, Claude (2009-04-01). "Structure and kinematics of the Indo-Burmese Wedge: Recent and fast growth of the outer wedge". Tectonics. 28 (2): TC2010. doi:10.1029/2008TC002276. ISSN 1944-9194.
- ^ a b Brunel, Maurice (2002). "Late Cretaceous to Eocene metamorphism of internal zones of the Indo-Burma range (western Myanmar): geodynamic implications. About the paper by Anne Socquet et al". Comptes Rendus Geoscience. 334 (12): 875–876. doi:10.1016/s1631-0713(02)01824-2.
- ^ a b c Bender, Friedrich (1983-02-14). Bannert, Dietrich; Brinckmann, Jörn u.a. (eds.). "Geology of Burma". www.schweizerbart.de. Retrieved 2017-11-16.
- ^ Mitchell, A. H. G. (1993-12-01). "Cretaceous–Cenozoic tectonic events in the western Myanmar (Burma)–Assam region". Journal of the Geological Society. 150 (6): 1089–1102. doi:10.1144/gsjgs.150.6.1089. ISSN 0016-7649. S2CID 129830325.