What is a charnockite in geology ?

Charnockite : definition

A charnockite is a granitic rock, whitish to greenish, characterized in particular by the presence of hypersthene and garnet (close to pyrope) next to quartz and feldspars (microcline, perthitic orthosis, oligoclase).

This rare rock which is found in certain Precambrian bases remains of disputed origin : magmatic for some, and considered then as a very quartzic granite with hypersthene and microcline, metamorphic of the granulite facies for others. The major characteristic of charnockites, the presence of orthopyroxene, can indeed have either a magmatic origin, or be produced by metamorphism (dehydration of biotite), hence some confusion about the origin of these rocks. It is now recommended to reserve the term charnockite for rocks of magmatic origin with orthopyroxene, even if they may have undergone deformation and / or subsequent metamorphism, leading to the formation of orthogneiss.

This rock is dedicated to Charnock, founder of Calcutta, whose tombstone was hewn from this rock.

ReCaptcha

This service is used to secure web forms of our website and required if you want to contact us. By accepting it you agree to Google's privacy policy: https://policies.google.com/privacy

Facebook

Our website allows you to like or share its content on Facebook social network. By activating and using it you agree to Facebook's privacy policy: https://www.facebook.com/policy/cookies/

YouTube

Integrated videos provided by YouTube are used on our website. By accepting to watch them you agree to Google's privacy policy: https://policies.google.com/privacy

Twitter

Integrated tweets and share services of Twitter are used on our website. By accepting and using these you agree to Twitter's privacy policy: https://help.twitter.com/en/rules-and-policies/twitter-cookies

PInterest

Our website allows you to share its content on PInterest social network. By activating and using it you agree to PInterest's privacy policy: https://policy.pinterest.com/en/privacy-policy/