# Roof pendant

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{{Short description|Geological feature}}
[[File:Mount Kailash - reurinkjan.jpg|200px|right|thumb|View of [Mount Kailash](/source/Mount_Kailash), Tibet (in the right distance), showing both the metasedimentary roof pendant and the underlying granite rock which caused the metamorphosis of the sediments above.]]

In [structural geology](/source/structural_geology), a '''roof pendant''', also known as a '''pendant''', is a mass of [country rock](/source/Country_rock_(geology)) that projects downward into and is entirely surrounded by an igneous intrusion such as a [batholith](/source/batholith) or other [pluton](/source/pluton). In lay terminology sometimes "rock hat" is used. A roof pendant is an erosional remnant that was created by the removal of the overlying country rock that formed the roof of the igneous intrusion that encloses it.<ref name="JerramOthers2011a">Jerram, D., and Petford, N., 2011. ''The Field Description of Igneous Rocks'', 2nd. Chichester, West Sussex, United Kingdom. 238 pp. pp. 9-10. {{ISBN|978-0-470-02236-8}}</ref><ref name="Bateman1992a">Bateman, P.C., 1992. ''Plutonism in the central part of the Sierra Nevada batholith, California.'' ''U.S. Geological Survey Profesional Paper'', 1483. 183 pp., p. 27</ref> If this downward protruding mass of roof rock separates two different plutons it is known as either '''septum''' or '''screen'''.<ref name="Bateman1992a"/><ref name="Bateman1988a">Bateman, P.C., 1988. "Constitution and genesis of the central part of the Sierra Nevada batholith, California." "U.S. Geological Survey Open-File Report", 88-382. 284 pp., p. 44</ref> Roof pendants typically have been strongly [metamorphosed](/source/metamorphosed) through the processes of [contact metamorphism](/source/contact_metamorphism).<ref name="BucherOthers2011a">Bucher, K, and R Grapes (2011) ''Petrogenesis of Metamorphic Rocks.'' Springer, New York, New York. 428 pp., pp. 237 and 242 {{ISBN|978-3-540-74168-8}}</ref>

A classic, well-documented example of a roof pendant is the strata that comprise [Mount Morrison](/source/Mount_Morrison_(California)) within the [Sierra Nevada](/source/Sierra_Nevada_(U.S.)) in [Mono](/source/Mono_County%2C_California) and [Fresno counties](/source/Fresno_County%2C_California), California. It lies midway between [Mono Lake](/source/Mono_Lake) on the north and [Bishop, California](/source/Bishop%2C_California), on the south. Mount Morrison consists of a roof pendant that underlies an area of {{convert|62|km2|sqmi|abbr=on}}. This roof pendant consists of a  {{convert|15,000|meter|feet|adj=mid|-thick}} sequence of complexly [folded](/source/Fold_(geology)) and [faulted](/source/Fault_(geology)) meta[sedimentary](/source/sedimentary) [strata](/source/strata) and meta[volcanic](/source/volcanic) strata. The eastern two-thirds of this roof pendant consists of [Cambrian](/source/Cambrian) to [Silurian](/source/Silurian) and [Pennsylvanian](/source/Pennsylvanian_(geology)) to [Permian](/source/Permian) metasedimentary strata. Metavolcanic rocks of [Mesozoic](/source/Mesozoic) age comprise the western third of the roof pendant. Mesozoic [granitic](/source/granite) rocks enclose and intrude the pendant rocks. These granitic rocks consist predominantly of [quartz monzonite](/source/quartz_monzonite) and [granodiorite](/source/granodiorite) with local, minor, scattered bodies of granite, [aplite](/source/aplite), [diorite](/source/diorite) and [gabbro](/source/gabbro). These pendants are part of a discontinuous, {{convert|140|km|mi|adj=mid|-long}}, northwest-trending belt of roof pendants that are preserved within the granitic plutons of Sierra Nevada.<ref name="GreeneOthers1999a">Greene, DC, and CH Stevens (1999) ''Stratigraphy, depositional history, and tectonic evolution of Paleozoic continental-margin rocks in roof pendants of the eastern Sierra Nevada, California.'' Geological Society of America Bulletin. 111(6):919-933.  {{doi|10.1130/0016-7606(1999)111<0919:SDHATE>2.3.CO;2}}</ref><ref name="GreeneOthers2002a">Greene, DC, and CH Stevens (2002) [http://personal.denison.edu/~greened/geol-map-mt-morrison.pdf ''Geologic Map of Paleozoic Rocks in the Mount Morrison Pendant, Eastern Sierra Nevada.''] California Map Sheet no 53. California Division of Mines and Geology, Sacramento, California.  Retrieved 13 February 2025.</ref><ref name="RhinehartOthers1964a">Rinehart, CD, DC Ross and LC Pakiser (1964) ''Geology and mineral deposits of the Mount Morrison quadrangle, Sierra Nevada, California.'' Professional Paper no. 385. United States Geological Survey, Reston, Virginia. 106 pp.  {{doi|10.3133/pp385}}</ref><ref name="RussellOthers1977a">Russell, S, and W Nokleberg (1977) ''Superimposition and timing of deformations in the Mount Morrison roof pendant and in the central Sierra Nevada, California.'' Geological Society of America Bulletin. 88(3):335-345.  {{doi|10.1130/0016-7606(1977)88<335:SATODI>2.0.CO;2}}</ref>

==See also==
*[Xenolith](/source/Xenolith)
*[Enclave](/source/Enclave_(geology))

==References==
{{Reflist}}

Category:Igneous intrusions

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Adapted from the Wikipedia article [Roof pendant](https://en.wikipedia.org/wiki/Roof_pendant) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Roof_pendant?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.