Leucogranite Intrusions in Eastern Kazakhstan: Age, Composition and Mechanisms of Formation.

There are several large intrusions composed of 60–90% leucogranites within Eastern Kazakhstan. The age of intrusions was determined that allows to conclude about the two stages of leucogranite intrusive magmatism: (1) in the Early Permian and (2) in the Early Triassic. Their formation occurred in an post-orogenic or intraplate geodynamic setting. The geochemical features of the leucogranites were considered that allows to conclude about the petrogenetic mechanisms of leucogranite magmas forming. They were formed as a result of partial melting of crustal substrates under the thermal influence of mafic magmas. Geochemical differences of leucogranites were due to different compositions of crustal substrates and different degrees of their melting. [ABSTRACT FROM AUTHOR]