petrographic province[¦pe·trə¦graf·ik ′präv·əns]
a region in which similar magmatic rocks are considered to have been formed during the same period. The rocks have a particular chemical or mineral composition, that distinguishes them from the same types of rocks in other regions.
The characteristic features of rocks in a petrographic province are assumed to have been conditioned by the differentiation or assimilation of a common magma. Therefore, the term “petrographic province” later was replaced by the term “comagmatic region.” Increased information about magmatic formations and the establishment of the close relationship between tectonics and magmatism have led to changes in the concept of petrographic provinces. Such a province is currently understood to be a large geotectonic element (folded region, platform) characterized by a natural association of magmatic rocks. The term “petrographic province” was first used in 1886 by the English geologist J. W. Judd.
REFERENCESLevinson-Lessing, F. Iu. Petrografiia, 5th ed. Moscow-Leningrad, 1940.
Judd, J. W. “On the Gabbros, Dolerites and Basalts of Tertiary Age in Scotland and Ireland.” Quarterly Journal of the Geological Society of London, 1886, vol. 42.