Editing Borneo (section)

===Geology===
{{see also|Geological history of Borneo}}

[[File:Regional map of SE Asia with Borneo Highlighted.svg|thumb|upright 1.2|left|Location of Borneo in [[Maritime Southeast Asia]].]]
Borneo was formed through [[Mesozoic]] accretion of microcontinental fragments, [[ophiolite]] terranes and [[island arc]] crust onto a [[Paleozoic]] continental core. At the beginning of the [[Cenozoic]] Borneo formed a [[promontory]] of [[Sundaland]] which partly separated from Asian mainland by the [[Tectonics of the South China Sea|proto-South China Sea]].<ref name="Geology of Borneo">{{cite journal|url=https://gsm.org.my/products/702001-100637-PDF.pdf|title=The origin of the 'circular basins' of Sabah, Malaysia|author1=Allagu Balaguru|author2=Gary Nichols|author3=Robert Hall|journal=Bulletin of the Geological Society of Malaysia, Royal Holloway University of London|via=Geological Society of Malaysia|year=2003|access-date=24 May 2019|page=337|archive-url=https://web.archive.org/web/20190524033404/https://gsm.org.my/products/702001-100637-PDF.pdf|archive-date=24 May 2019|url-status=dead}}</ref> The oceanic part of the proto-South China Sea was [[subduction|subducted]] during the [[Paleogene]] period and a large [[accretionary complex]] formed along the northwestern of the island of Borneo. In the [[early Miocene]] uplift of the accretionary complex occurred as a result of underthrusting of thinned continental crust in northwest.<ref name="Geology of Borneo"/> The uplift may have also resulted from shortening due to the counter-clockwise rotation of Borneo between 20 and 10 [[mega-annum]] (Ma) as a consequence of [[Australia (continent)|Australia]]-Southeast Asia collision.<ref name="Geology of Borneo"/> Large volumes of [[sediment]] were shed into basins, which scattered offshore to the west, north and east of Borneo as well into a [[Neogene]] basin which is currently exposed in large areas of eastern and southern [[Sabah]]. In southeast Sabah, the [[Miocene]] to recent island arc terranes of the [[Sulu Archipelago]] extend onshore into Borneo with the older [[volcanic arc]] was the result of southeast dipping subduction while the younger volcanics are likely resulted from northwest dipping subduction the [[Celebes Sea]].<ref name="Geology of Borneo"/>

[[File:Jack fish and reef sharks.jpg|thumb|left|Marine life off the coast of Borneo, in the Sulu Sea]]

Before sea levels rose at the end of the [[Last Glacial Period|last ice age]], Borneo was part of the mainland of Asia, forming, with [[Java]] and [[Sumatra]], the upland regions of a peninsula that extended east from present day [[Indochina]]. The [[South China Sea]] and [[Gulf of Thailand]] now submerge the former low-lying areas of the peninsula. Deeper waters separating Borneo from neighbouring [[Sulawesi]] prevented a land connection to that island, creating the divide known as [[Wallace's Line]] between Asian and Australia-[[New Guinea]] biological regions.<ref>{{cite book|author=James Allan Taylor|title=Biogeography: Recent Advances and Future Directions|url=https://books.google.com/books?id=xz9dWjh_CAsC&pg=PA178|year=1984|publisher=Rowman & Littlefield|isbn=978-0-389-20507-4|pages=178–}}</ref><ref>{{cite web|url=http://www.starfish.ch/dive/Wallacea.html|title=Wallacea|author=Teresa Zubi|publisher=Starfish|date=25 October 2015|access-date=26 May 2017|archive-url=https://web.archive.org/web/20170525180130/http://www.starfish.ch/dive/Wallacea.html|archive-date=25 May 2017|url-status=dead}}</ref> The island today is surrounded by the [[South China Sea]] to the north and northwest, the [[Sulu Sea]] to the northeast, the Celebes Sea and the [[Makassar Strait]] to the east, and the [[Java Sea]] and [[Karimata Strait]] to the south. To the west of Borneo are the [[Malay Peninsula]] and [[Sumatra]]. To the south and east are islands of Indonesia: [[Java (island)|Java]] and [[Sulawesi]], respectively. To the northeast are the [[Philippines|Philippine Islands]]. With an area of {{convert|743330|km2|sqmi}}, it is the third-largest island in the world, and is the largest island of [[Asia]] (the largest continent). Its highest point is [[Mount Kinabalu]] in Sabah, Malaysia, with an elevation of {{convert|4095|m|ft|0|abbr=on}}.<ref name="highest summit"/>
[[File:Lahan basah Taman Nasional Danau Sentarum, Kalimantan Barat.jpg|thumb|[[Lake Sentarum National Park|Lake Sentarum]], Kapuas Hulu Regency, West Kalimantan]]
The largest river system is the [[Kapuas River|Kapuas]] in [[West Kalimantan]], with a length of {{convert|1143|km|mi|abbr=on}}.<ref name="TanMerdikawati2015"/> Other major rivers include the [[Mahakam River|Mahakam]] in [[East Kalimantan]] ({{convert|980|km|mi|abbr=on}} long),<ref>{{cite book|author=Tomas Tomascik|title=The Ecology of the Indonesian Seas|url=https://books.google.com/books?id=0Kc80Hd2HagC&pg=PP54|year=1997|publisher=Oxford University Press|isbn=978-0-19-850186-2|pages=54–}}</ref> the [[Barito River|Barito]], [[Kahayan River|Kahayan]], and [[Mendawai River|Mendawai]] in [[South Kalimantan]] ({{convert|1090|km|mi|abbr=on}}, {{convert|658|km|mi|abbr=on}}, and {{convert|616|km|mi|abbr=on}} long respectively),<ref>{{cite book|author1=Khee Giap Tan|author2=Mulya Amri|author3=Linda Low|author4=Kong Yam Tan|title=Competitiveness Analysis and Development Strategies for 33 Indonesian Provinces|url=https://books.google.com/books?id=Q526CgAAQBAJ&pg=PA338|year=2013|publisher=World Scientific|isbn=978-981-4504-86-7|pages=338–}}</ref> [[Rajang River|Rajang]] in Sarawak ({{convert|565|km|mi|abbr=on}} long)<ref>{{cite book|title=Tropical River Fisheries Valuation: Background Papers to a Global Synthesis|url=https://books.google.com/books?id=mmrmRVVSiIYC&pg=PT218|year=2008|publisher=WorldFish|isbn=978-983-2346-61-6|pages=218–}}</ref> and [[Kinabatangan River|Kinabatangan]] in Sabah ({{convert|560|km|mi|abbr=on}} long).<ref>{{cite book|author1=Uwe Tietze|author2=Food and Agriculture Organization of the United Nations|title=Credit and Microfinance Needs in Inland Capture Fisheries Development and Conservation in Asia|url=https://books.google.com/books?id=ihTrWUKDvLUC&pg=PA131|year=2007|publisher=Food & Agriculture Org.|isbn=978-92-5-105756-8|pages=131–}}</ref> Borneo has significant cave systems. In Sarawak, the Clearwater Cave has one of the world's longest underground rivers while [[Deer Cave]] is home to over three million [[bat]]s, with [[guano]] accumulated to over {{convert|100|m}} deep.<ref>{{cite web|url=http://www.sarawak.gov.my/ebook/Sarawak_Tourism/Visitor_Guide/files/basic-html/page100.html|title=Sarawak Visitors Guide|publisher=Sarawak State Government|access-date=26 May 2017|page=100}}</ref> The [[Gomantong Caves]] in Sabah has been dubbed as the "Cockroach Cave" due to the presence of millions of cockroaches inside the cave.<ref>{{cite web|url=http://voices.nationalgeographic.com/2015/10/29/billions-of-bugs-feast-on-flesh-and-dung-in-borneo/|archive-url=https://web.archive.org/web/20151030152107/http://voices.nationalgeographic.com/2015/10/29/billions-of-bugs-feast-on-flesh-and-dung-in-borneo/|url-status=dead|archive-date=30 October 2015|title=WATCH: Billions of Bugs Feast on Flesh and Dung in Borneo|author=Nora Rappaport|publisher=[[National Geographic Society|National Geographic]]|date=29 October 2015|access-date=26 May 2017}}</ref><ref>{{cite web|url=http://www.ibtimes.co.uk/cockroach-cave-where-billions-bugs-feed-dead-animals-dung-video-1526507|title=Cockroach cave: Where billions of bugs feed on dead animals and dung [Video]|author=Sean Martin|publisher=International Business Times (UK)|date=31 October 2015|access-date=26 May 2017}}</ref> The [[Gunung Mulu National Park]] in Sarawak and [[Sangkulirang-Mangkalihat Karst]] in East Kalimantan which particularly a [[karst]] areas contains thousands of smaller caves.<ref>{{cite book|author1=Quentin Phillipps|author2=Karen Phillipps|title=Phillipps' Field Guide to the Mammals of Borneo and Their Ecology: Sabah, Sarawak, Brunei, and Kalimantan|url=https://books.google.com/books?id=0SxzCwAAQBAJ&pg=PA31|date=10 May 2016|publisher=Princeton University Press|isbn=978-0-691-16941-5|pages=31–}}</ref>