Petrology

A thin section of a volcanic sand grain seen under the microscope, with plane-polarized light in the upper picture, and cross-polarized light in the lower picture. Scale box is 0.25 mm.

Petrology (from Ancient Greek πέτρος (pétros) 'rock', and -λογία (-logía) 'study of') is the branch of geology that studies rocks, their mineralogy, composition, texture, structure and the conditions under which they form.^[1] Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology.^[2] Igneous and metamorphic petrology are commonly taught together because both make heavy use of chemistry, chemical methods, and phase diagrams. Sedimentary petrology is commonly taught together with stratigraphy because it deals with the processes that form sedimentary rock.^[3] Modern sedimentary petrology is making increasing use of chemistry.

^ The 22nd edition of the Manual of mineral science. Buch. New York: Wiley. 2002. p. 1. ISBN 978-0-471-25177-4.
^ Blatt, Harvey; Tracy, Robert J.; Owens, Brent E. (2006). Petrology: igneous, sedimentary and metamorphic (3rd ed.). New York: Freeman. ISBN 978-0-7167-3743-8.
^ Frost, B. R.; Frost, C. D. (2014). Essentials of Igneous and Metamorphic Petrology. Cambridge University Press.

[1] The 22nd edition of the Manual of mineral science. Buch. New York: Wiley. 2002. p. 1. ISBN 978-0-471-25177-4.

[2] Blatt, Harvey; Tracy, Robert J.; Owens, Brent E. (2006). Petrology: igneous, sedimentary and metamorphic (3rd ed.). New York: Freeman. ISBN 978-0-7167-3743-8.

[3] Frost, B. R.; Frost, C. D. (2014). Essentials of Igneous and Metamorphic Petrology. Cambridge University Press.

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