Editing Mount Everest (section)

==Geology==

Geologists have subdivided the rocks comprising Mount Everest into three units called [[Geologic formation|formations]].<ref name="Scientiav5">Yin, C.-H., and S.-T. Kuo. 1978. "Stratigraphy of the Mount Jolmo Langma and its north slope." ''Scientia Sinica''. v. 5, pp. 630–644</ref><ref name="IslandArcv14">Sakai, H., M. Sawada, Y. Takigami, Y. Orihashi, T. Danhara, H. Iwano, Y. Kuwahara, Q. Dong, H. Cai, and J. Li. 2005. "Geology of the summit limestone of Mount Qomolangma (Everest) and cooling history of the Yellow Band under the Qomolangma detachment." [[Island Arc (journal)|''Island Arc'']]. v. 14 no. 4 pp. 297–310.</ref> Each formation is separated from the other by low-angle [[Fault (geology)|faults]], called [[Detachment fault|detachments]], along which they have been thrust southward over each other. From the summit of Mount Everest to its base these rock units are the Qomolangma Formation, the [[North Col]] Formation, and the [[Rongbuk Glacier|Rongbuk Formation]].

The Qomolangma Formation, also known as the Jolmo Lungama Formation,<ref name=Everest1953Geo/> runs from the summit to the top of the Yellow Band, about {{convert|8600|m|ft|abbr=on}} above sea level. It consists of greyish to dark grey or white, parallel laminated and bedded, [[Ordovician]] limestone interlayered with subordinate beds of recrystallised [[Dolomite (rock)|dolomite]] with [[argillaceous minerals|argillaceous]] [[Sediment|laminae]] and [[siltstone]]. Gansser first reported finding microscopic fragments of [[crinoid]]s in this [[limestone]].<ref>Gansser, A. 1964. ''Geology of the Himalayas'', John Wiley Interscience, London, 1964 289 pp.</ref><ref>{{cite web |last=Rosenberg |first=Matt |url=http://geology.about.com/library/bl/peaks/bleverest.htm |title=A site which uses this dramatic fact first used in illustration of "deep time" in John McPhee's book ''Basin and Range'' |publisher=Geology.about.com |access-date=17 June 2016 |archive-date=3 March 2016 |archive-url=https://web.archive.org/web/20160303232401/http://geology.about.com/library/bl/peaks/bleverest.htm |url-status=dead }}</ref> Later [[petrograph]]ic analysis of samples of the limestone from near the summit revealed them to be composed of carbonate pellets and finely fragmented remains of [[trilobite]]s, crinoids, and [[ostracods]]. Other samples were so badly sheared and recrystallised that their original constituents could not be determined. A thick, white-weathering [[thrombolite]] bed that is {{convert|60|m|ft|abbr=on}} thick comprises the foot of the "[[Three Steps|Third Step]]", and base of the summit pyramid of Everest. This bed, which crops out starting about {{convert|70|m|ft|abbr=on}} below the summit of Mount Everest, consists of sediments trapped, bound, and cemented by the biofilms of micro-organisms, especially [[cyanobacteria]], in shallow marine waters. The Qomolangma Formation is broken up by several high-angle faults that terminate at the low angle [[normal fault]], the Qomolangma Detachment. This detachment separates it from the underlying Yellow Band. The lower five metres of the Qomolangma Formation overlying this detachment are very highly deformed.<ref name="Scientiav5"/><ref name="IslandArcv14"/><ref name="MyrowOthers2009">Myrow, P.M., N.C. Hughes, M.P. Searle, C.M. Fanning, S.-C. Peng, and S.K. Parcha, 2009, "Stratigraphic correlation of Cambrian Ordovician deposits along the Himalaya: Implications for the age and nature of rocks in the Mount Everest region". ''Geological Society of America Bulletin''. v. 121, no. 3–4, pp. 323–332.</ref>

The bulk of Mount Everest, between {{convert|7000|and|8,600|m|ft|abbr=on}}, consists of the [[North Col]] Formation, of which the Yellow Band forms the upper part between {{convert|8200|to|8,600|m|ft|abbr=on}}. The Yellow Band consists of [[intercalation (geology)|intercalated]] beds of Middle Cambrian [[diopside]]-[[epidote]]-bearing [[marble]], which weathers a distinctive yellowish brown, and [[muscovite]]-[[biotite]] phyllite and [[schist|semischist]]. Petrographic analysis of marble collected from about {{convert|8300|m|ft|abbr=on}} found it to consist as much as five per cent of the ghosts of recrystallised crinoid ossicles. The upper five metres of the Yellow Band lying adjacent to the Qomolangma Detachment is badly deformed. A {{convert|5|–|40|cm|in|abbr=on}} thick fault [[breccia]] separates it from the overlying Qomolangma Formation.<ref name="Scientiav5"/><ref name="IslandArcv14"/><ref name="MyrowOthers2009"/>

The remainder of the North Col Formation, exposed between {{convert|7000|to|8,200|m|ft|abbr=on}} on Mount Everest, consists of interlayered and deformed schist, [[phyllite]], and minor marble. Between {{convert|7600|and|8,200|m|ft|abbr=on}}, the North Col Formation consists chiefly of biotite-quartz phyllite and chlorite-biotite phyllite intercalated with minor amounts of biotite-[[sericite]]-quartz schist. Between {{convert|7000|and|7,600|m|ft|abbr=on}}, the lower part of the North Col Formation consists of biotite-quartz schist intercalated with epidote-quartz schist, biotite-calcite-quartz schist, and thin layers of [[quartz]]ose [[marble]]. These metamorphic rocks appear to be the result of the metamorphism of Middle to Early [[Cambrian]] deep sea [[flysch]] composed of interbedded, [[mudstone]], [[shale]], clayey [[sandstone]], calcareous sandstone, [[graywacke]], and sandy limestone. The base of the North Col Formation is a regional low-angle normal fault called the "Lhotse detachment".<ref name="Scientiav5"/><ref name="IslandArcv14"/><ref name="MyrowOthers2009"/>

Below 7,000&nbsp;m (23,000&nbsp;ft), the Rongbuk Formation underlies the North Col Formation and forms the base of Mount Everest. It consists of [[sillimanite]]-[[K-feldspar]] grade schist and [[gneiss]] intruded by numerous [[sill (geology)|sills]] and [[dike (geology)|dikes]] of [[granite|leucogranite]] ranging in thickness from 1&nbsp;cm to 1,500&nbsp;m (0.4&nbsp;in to 4,900&nbsp;ft).<ref name="IslandArcv14"/><ref name="Searle1999a">Searle, M.P. (1999) "Emplacement of Himalayan leucogranites by magma injection along giant sill complexes: examples from the Cho Oyu, Gyachung Kang and Everest leucogranites (Nepal Himalaya)". ''Journal of Asian Earth Sciences''. v. 17, no. 5–6, pp. 773–783.</ref> These leucogranites are part of a belt of Late [[Oligocene]]–[[Miocene]] intrusive rocks known as the Higher Himalayan leucogranite. They formed as the result of partial melting of [[Paleoproterozoic]] to Ordovician high-grade metasedimentary rocks of the Higher Himalayan Sequence about 20 to 24&nbsp;million years ago during the subduction of the Indian Plate.<ref name="GuoOthers2012">Guo, Z., and M. Wilson (2012) "The Himalayan leucogranites: Constraints on the nature of their crustal source region and geodynamic setting." ''Gondwana Research''. v. 22, no. 2, pp. 360–376.</ref>

Mount Everest consists of [[Sedimentary rock|sedimentary]] and [[Metamorphic rock|metamorphic]] rocks that have been faulted southward over continental crust composed of Archean granulites of the Indian Plate [[Geology of the Himalaya|during the Cenozoic collision of India with Asia]].<ref name=pbs_nature>{{cite web|url=https://www.pbs.org/wnet/nature/the-himalayas-tectonic-motion-making-the-himalayas/6342/|title=Tectonic Motion: Making the Himalayas|date=11 February 2011|website=Nature on PBS|access-date=6 February 2016|archive-date=12 May 2022|archive-url=https://web.archive.org/web/20220512085808/https://www.pbs.org/wnet/nature/the-himalayas-tectonic-motion-making-the-himalayas/6342/|url-status=live}}</ref><ref name=USGS>{{cite web | url = http://pubs.usgs.gov/gip/dynamic/himalaya.html | title = The Himalayas: Two continents collide | publisher = USGS | date = 5 May 1999 | access-date = 6 February 2016 | archive-date = 10 May 2020 | archive-url = https://web.archive.org/web/20200510204755/https://pubs.usgs.gov/gip/dynamic/himalaya.html | url-status = live }}</ref><ref>{{Cite web|url=http://www.columbia.edu/cu/pr/95/18688.html|title=Press Release: An Earth Plate Is Breaking in Two|website=www.columbia.edu|access-date=6 February 2016|archive-date=18 May 2017|archive-url=https://web.archive.org/web/20170518041545/http://www.columbia.edu/cu/pr/95/18688.html|url-status=live}}</ref> Current interpretations argue that the Qomolangma and North Col formations consist of marine sediments that accumulated within the continental shelf of the northern passive continental margin of India before it collided with Asia. The Cenozoic collision of India with Asia subsequently deformed and metamorphosed these strata as it thrust them southward and upward.<ref name="MyrowOthers2003a">Myrow, P.M., N.C. Hughes, T.S. Paulsen, I.S. Williams, S.K. Parcha, K.R. Thompson, S.A. Bowring, S.-C. Peng, and A.D. Ahluwalia. 2003. "Integrated tectonostratigraphic reconstruction of the Himalaya and implications for its tectonic reconstruction." ''Earth and Planetary Science Letters''. vol. 212, pp. 433–441.</ref><ref name="MyrowOthers2012a">Myrow, P.M., N.C. Hughes, J.W. Goodge, C.M. Fanning, I.S. Williams, S.-C. Peng, O.N. Bhargava, S.K. Tangri, S.K. Parcha, and K.R. Pogue. 2010. "Extraordinary transport and mixing of sediment across Himalayan central Gondwanaland during the Cambrian-Ordovician." ''Geological Society of America Bulletin''. vol. 122, pp. 1660–1670.</ref> The Rongbuk Formation consists of a sequence of high-grade metamorphic and granitic rocks that were derived from the alteration of high-grade metasedimentary rocks. During the collision of India with Asia, these rocks were thrust downward and to the north as they were overridden by other strata; heated, metamorphosed, and partially melted at depths of over {{convert|15 to 20|km|mi}} below sea level; and then forced upward to surface by thrusting towards the south between two major detachments.<ref name="Searle2012a">Searle, M. 2012. ''Colliding Continents: A geological exploration of the Himalaya, Karakoram, & Tibet.'' Oxford University Press, Oxford. 464 pp. {{ISBN|978-0-19-965300-3}}</ref> Mount Everest is rising by about 2&nbsp;mm per year.<ref name="HanOthers2024">Han, X., Dai, J.G., Smith, A.G., Xu, S.Y., Liu, B.R., Wang, C.S., and Fox, M., 2024. "Recent uplift of Chomolungma enhanced by river drainage piracy." ''Nature Geoscience. published online September 30, 2024, pp.1-7.</ref>

===IUGS geological heritage site===
In respect of the recognition of the "highest rocks on the planet" as fossiliferous, marine limestone, the Ordovician Rocks of Mount Everest were included by the [[International Union of Geological Sciences]] (IUGS) in its assemblage of 100 geological heritage sites around the world in a listing published in October 2022. The organisation defines an IUGS Geological Heritage Site as "a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history."<ref>{{cite web |title=The First 100 IUGS Geological Heritage Sites |url=https://iugs-geoheritage.org/videos-pdfs/iugs_first_100_book_v2.pdf |archive-url=https://web.archive.org/web/20221027114156/https://iugs-geoheritage.org/videos-pdfs/iugs_first_100_book_v2.pdf |archive-date=2022-10-27 |url-status=live |website=IUGS International Commission on Geoheritage |publisher=IUGS |access-date=10 November 2022}}</ref>

{{wide image|File:Close Up View of Mount Everest from Kala Patthar (5644 m) in 2023-IMG-3485.jpg|1000px|align-cap=center|Mount Everest with snow melted, showing upper geologic layers in bands}}