Petrochemical criteria for a genetic association between gabbros and associated granitoids

Autor: Fershtater, G. B., Borodina, N. S.
Zdroj: International Geology Review; October 1977, Vol. 19 Issue: 10 p1121-1132, 12p
Abstrakt: Formation of the principal types of the water-poor granitoid series (gabbrogranitic, tonalite-granodioritic, and adamellite-granitic) commences with the gabbros. Gabbros from these series are distinguished from those associated with ultrabasic rocks by low content of magnesium and calcium and greater concentration of iron, titanium, and alkalies. Features of chemical composition of the "granitoid" gabbros associate them with various types of continental basalts. Gabbros involved in various types of the granitoid series, while similar in composition, are distinguished by the content of iron, titanium, magnesium, and calcium. Granitoids of the corresponding series also have analogous features. Such inheritance of chemical composition, the constancy of the ratios of the femic components in all members of each series, and certain other petrochemical features may serve as criteria for the genetic connection between gabbros and associated granitoids. These features reflect deep-seated physicochemical patterns associated with the very essence of the magmatic rocks, their origin. —Authors.
Databáze: Supplemental Index