Formation and composition of H2O-undersaturated granitic melts

Abstract

Granites are a very common component of the continental crust, and granitic melts are the most important medium for the transport of silicon, alkali metals and some associated, less abundant, elements from lower to higher crustal levels. Granites have been the subject of numerous petrographic and experimental investigations. The first systematic experimental research was performed in the synthetic haplogranitic system Qz-Ab-Or-H2O (Tuttle & Bowen 1958, Luth, Jahns & Tuttle 1964). Other investigations with natural rocks as the starting material were performed by Winkler and co-workers (summarized in Winkler 1979). The results of these H2O-saturated experiments emphasized that granitic magmas can exist at relatively low temperatures within the continental crust, and that many crystalline rocks can be the source of granitic melts.