Editing Kimberlite (section)

== Morphology and volcanology ==

[[File:Kimberlite Pipes in Africa.png|thumb|Distribution of kimberlites in Africa. Cratons: CA-Central African (Kasai), SA-South African (Kalahari), WA-West African; Kimberlites (shown as red dots): B-Banankoro, Cu-Cuango Valley, Do-Dokolwayo, F-Finsch, G-Gope, J-Kwaneng, Ja-Jagersfontein, k-Koidu, Kb-Kimberley, Ko-Koffiefontein, L-Letlhakane, Le-Letseng, Lu-Lunda, M-Mitzic, Mb-Mbuji-Mayi, Mw-Mwadui, O-Orapa, P-[[Premier Mine|Premier]], R-River Ranch, V-Venetia.]]
Many kimberlite structures are emplaced as carrot-shaped, vertical intrusions termed "[[Volcanic pipe|pipes]]". This classic carrot shape is formed due to a complex intrusive process of kimberlitic magma, which inherits a large proportion of CO<sub>2</sub> (lower amounts of H<sub>2</sub>O) in the system, which produces a deep explosive boiling stage that causes a significant amount of vertical flaring.<ref>{{cite journal|last1=Bergman|first1=Steven C.|title=Lamproites and other potassium-rich igneous rocks: a review of their occurrence, mineralogy and geochemistry|journal=Geological Society, London, Special Publications|date=1987|volume=30|issue=1|pages=103–190|doi=10.1144/GSL.SP.1987.030.01.08|bibcode=1987GSLSP..30..103B|s2cid=129449668}}</ref> Kimberlite classification is based on the recognition of differing rock [[facies]]. These differing facies are associated with a particular style of magmatic activity, namely crater, diatreme and [[hypabyssal]] rocks.<ref>Clement, C. R., 1982: A comparative geological study of some major kimberlite pipes in the Northern Cape and Orange free state. PhD Thesis, University of Cape Town.</ref><ref>Clement, C. R., and Skinner, E. M. W. 1985: A textural-genetic classification of kimberlites. Transactions of the Geological Society of South Africa. pp.&nbsp;403–409.</ref>

The [[geomorphology|morphology]] of kimberlite pipes and their classical carrot shape is the result of explosive [[Volcanic pipe|diatreme]] [[volcanism]] from very deep [[Earth's mantle|mantle]]-derived sources. These volcanic explosions produce vertical columns of rock that rise from deep magma reservoirs. The eruptions forming these [[volcanic pipe|pipes]] fracture the surrounding rock as it explodes, bringing up unaltered [[xenolith]]s of peridotite to surface. These [[xenolith]]s provide valuable information to geologists about mantle conditions and composition.<ref>{{Cite journal |last=Sparks |first=R.S.J. |date=2013-05-30 |title=Kimberlite Volcanism |url=https://www.annualreviews.org/doi/10.1146/annurev-earth-042711-105252 |journal=Annual Review of Earth and Planetary Sciences |language=en |volume=41 |issue=1 |pages=497–528 |doi=10.1146/annurev-earth-042711-105252 |bibcode=2013AREPS..41..497S |issn=0084-6597|url-access=subscription }}</ref><ref>{{Cite web |title=kimberlite eruption {{!}} volcanism {{!}} Britannica |url=https://www.britannica.com/science/kimberlite-eruption |access-date=2022-07-14 |website=www.britannica.com |language=en}}</ref> The morphology of kimberlite pipes is varied, but includes a sheeted dyke complex of tabular, vertically dipping feeder dykes in the root of the pipe, which extends down to the mantle. Within {{convert|1.5|-|2|km|ft|abbr=on}} of the surface, the highly pressured magma explodes upwards and expands to form a conical to cylindrical [[diatreme]], which erupts to the surface. The surface expression is rarely preserved but is usually similar to a [[maar|maar volcano]]. Kimberlite dikes and sills can be thin (1&ndash;4 meters), while pipes range in diameter from about 75 meters to 1.5 kilometers.<ref>{{cite book|last1=Kjarsgaard|first1=B. A.|chapter=Kimberlite pipe models: significance for exploration|editor-last1=Milkereit|editor-first1=B.|title=Proceedings of Exploration 07: Fifth Decennial International Conference on Mineral Exploratio|date=2007|publisher=[[Decennial Mineral Exploration Conferences]], 2007|pages=667&ndash;677|chapter-url=http://www.dmec.ca/ex07-dvd/E07/pdfs/46.pdf|access-date=1 March 2018|archive-date=3 August 2021|archive-url=https://web.archive.org/web/20210803232440/http://www.dmec.ca/ex07-dvd/E07/pdfs/46.pdf|url-status=dead}}</ref>