The Sivalik Hills are amountain range of the outerHimalayas that stretches over about 2,400 km (1,500 mi) from theIndus River eastwards close to theBrahmaputra River; they are 10–50 km (6.2–31.1 mi) wide with an average elevation of 1,500–2,000 m (4,900–6,600 ft). Between theTeesta andRaidāk Rivers is a gap of about 90 km (56 mi).[3] They are known for theirNeogene andPleistocene aged vertebrate fossils.[4]
Geologically, the Sivalik Hills belong to theTertiarydeposits of the outer Himalayas.[5] They are chiefly composed ofsandstone andconglomerate rock formations, which are the solidifieddetritus of the Himalayas[5] to their north; they are poorly consolidated. The sedimentary rocks comprising the hills are believed to be 16–5.2 million years old.[6]
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 alluvialBhabar zone makes the transition to the nearly level plains. Rainfall, especially during the summermonsoon, 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 theTerai or plains.[7]
Skeleton of the gigantic tortoiseMegalochelys atlas, the largest known to have ever existed, and one of the best known Sivalik fossils
The Sivalik Hills are well known for fossils of vertebrates, spanning from the EarlyMiocene, until theMiddle Pleistocene, around 18 million to 600,000 years ago.[8][9]
Remains of theLower-Middle PaleolithicSoanian culture dating to around 500,000 to 125,000 yearsBefore Present were found in the Sivalik region.[14] Contemporary to theAcheulean, the Soanian culture is named after theSoan Valley in the Sivalik Hills ofPakistan. The Soanian archaeological culture is found across Sivalik region in present-day India, Nepal and Pakistan.[2]
Thecarbon stock andcarbon sequestration rates of the Churia forests differ among different forest management regimes and are highest in protected areas.[15][16]
^Kaur, A. P. (2022). "New fossil mammalian assemblages and first record of ostrich from the Pinjore (Pinjor) formation (2.58–0.63 Ma) of Siwalik Hills near Chandigarh, northern India".Quaternary Science Reviews.293 107694.Bibcode:2022QSRv..29307694K.doi:10.1016/j.quascirev.2022.107694.
^Patnaik, R. (2013). "Indian Neogene Siwalik Mammalian Biostratigraphy. An Overview".Fossil Mammals of Asia. New York Chichester, West Sussex: Columbia University Press.doi:10.7312/wang15012-017.
^Lycett, S. J. (2007). "Is the Soanian techno-complex a Mode 1 or Mode 3 phenomenon? A morphometric assessment".Journal of Archaeological Science.34 (9):1434–1440.Bibcode:2007JArSc..34.1434L.doi:10.1016/j.jas.2006.11.001.
^Thapa, H. B. (2014).Churia forests of Nepal(PDF). Forest Resource Assessment Nepal, Department of Forest Research and Survey, Ministry of Forests and Soil Conservation, Government of Nepal.LCCN2015515752. Archived fromthe original(PDF) on 8 May 2017.
