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The Sivalik Hills is a mountain range of the outer Himalayas also known as ''Manak Parbat'' in ancient times. Shivalik literally means 'tresses of Shiva’.〔Balokhra, J. M. (1999). ''The Wonderland of Himachal Pradesh''. Revised and enlarged 4th edition. H.G. Publications, New Delhi.〕 This range is about long enclosing an area that starts almost from the Indus and ends close to the Brahmaputra, with a gap of about between the Teesta and Raidak rivers in Assam. The width of the Sivalik Hills varies from , their average elevation is .〔Kohli, M. S. (2004). ''Mountains of India: Tourism, Adventure, Pilgrimage''. Indus Publishing, New Delhi.〕 Other spelling variations used include ''Shivalik'' and ''Siwalik'', originating from the Hindi and Nepali word ''shiwālik parvat''. Other names include ''Churia hills'', ''Chure hills'', and ''Margalla hills''. ==Geology== Geologically, the Sivalik Hills belong to the tertiary deposits of the outer Himalayas. They are chiefly composed of sandstone and conglomerate rock formations, which are the solidified detritus of the great mountain range to their north, but often poorly consolidated. The remnant magnetization of siltstones and sandstones suggests a depositional age of 16-5.2 million years with Karnali River exposing the oldest part of the Sivalik Hills in Nepal.〔Gautam, P., Fujiwara, Y. (2000). (''Magnetic polarity stratigraphy of Siwalik Group sediments of Karnali River section in western Nepal'' ). Geophysical Journal International 142 (3): 812–824.〕 They are the southernmost and geologically youngest east-west mountain chain of the Himalayas. They have many sub-ranges and extend west from Arunachal Pradesh through Bhutan to West Bengal, and further westward through Nepal and Uttarakhand, continuing into Himachal Pradesh and Kashmir. The hills are cut through at wide intervals by numerous large rivers flowing south from the Himalayas. They are bounded on the south by a fault system called the Main Frontal Thrust, with steeper slopes on that side. Below this, the coarse alluvial Bhabhar zone makes the transition to the nearly level plains. Rainfall, especially during the summer monsoon, percolates into the bhabar, then is forced to the surface by finer alluvial layers below it in a zone of springs and marshes along the northern edge of the Terai or plains. North of the Sivalik Hills the 1,500-3,000 meter Lesser Himalayas also known as the Mahabharat Range rise steeply along fault lines. In many places the two ranges are adjacent but in other places structural valleys 10–20 km wide separate them. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sivalik Hills」の詳細全文を読む スポンサード リンク
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