科研之友
微信
新浪微博
Facebook
分享链接
摘要
Variscan granitoids occur in the southeastern part of the Tisza Mega Unit of Hungary. The presence of amphibole, calc-alkaline-type Mg-rich biotite in metaluminous basic enclaves, and muscovite and Fe-Al-biotite in peraluminous granitoids, suggests a mixed I-S-type origin. Two types of muscovite have been identified: a primary euhedral to subhedral, Ti-Na-Al rich variety, crystallized after Fe-rich peraluminous biotite in the two-mica granite and in muscovite granite, and a secondary subhedral Si enriched and Mg-bearing, Ti-poor mica formed as a hydrothermal alteration product of feldspars, and is present in all rock types. Given the compositional continuum of %26quot;white micas%26quot;, we suggest that magmatic crystallization was followed by autometasomatic and hydrothermal activity, due to a water-rich liquid trapped in the rock during the final stages of magmatic activity. Based on the bulk composition of the prevailing rock-type, the abundance of primary muscovite, the majority of the granitoid magma crystallized from a water-saturated peraluminous melt for which the pressure was 490-600 MPa, the temperatures were 650-685 degrees C and the depth of the intrusion was a minimum of 15 km.
- 出版日期2012
