论文部分内容阅读
Dahuabei pluton in the Wulashan area,Inner Mongolia,is an alkaline and peraluminous granitic pluton.LA-ICPMS U-Pb dating of zircons indicates that this pluton crystallized at 330±10 Myr.The pluton did not experience apparent zircon fractionation.The consistent temperatures between Zr saturation(765℃) and the average zircon-rutile Ti equilibrium(780℃),together with zircon ages and their CL images,indicated that there were no inherited zircons in this pluton.Through the simulation of the dry-system crystallization process of magma cooling at 200 MPa and 1100-709℃,the phase diagram and composition evolution tendency of different phases were obtained.The magma reached its liquidus at 1069℃.Sanidine was the first crystallized phase;at 709℃the residual magma was less than 4%,and the range of 1069-719℃should be the most suitable approach to the real condition.It is shown that at least some part of the pluton underwent such isobaric equilibrium crystallization processes during its crystallization.
Dahuabei pluton in the Wulashan area, Inner Mongolia, is an alkaline and peraluminous granitic pluton. LA-ICPMS U-Pb dating of zircons indicates that this pluton crystallized at 330 ± 10 Myr. Pluton did not experience apparent zircon fractionation. between Zr saturation (765 ° C) and the average zircon-rutile Ti equilibrium (780 ° C), together with zirconations and their CL images, indicates that there was no inherited zircons in this pluton. Through the simulation of the dry-system crystallization process of magma cooling at 200 MPa and 1100-709 ° C, the phase diagram and composition evolution tendency of different phases were obtained. The magma reached its liquidus at 1069 ° C.Sanidine was the first crystallized phase; at 709 ° C. the residual magma was less than 4%, and the range of 1069-719 ° C should be the most suitable approach to the real condition. It is at least some part of the pluton underwent such isobaric equilibrium crystallization processes during its crystallization.