【摘要】 通过对大别山太湖地区榴辉岩的岩石学、矿物成分和峰期变质P-T条件的研究表明,南大别榴辉岩可分为:①高压榴辉岩;②高压/超高压过渡榴辉岩;③超高压榴辉岩。它们的峰期变质P-T条件分别为:T=570℃～680℃,P=2.00 GPa～2.40 GPa;T=650℃～810℃,P=2.70 GPa～3.20 GPa;T=760℃～980℃,P=3.50 GPa～4.00 GPa,表明三类榴辉岩形成于不同的变质环境中。其中高压/超高压过渡榴辉岩是本次研究新近确定的,该类榴辉岩无论是在变质环境,还是在岩石结构、成分特征方面,均显示了高压-超高压过渡变质的特征。这种榴辉岩的存在解释了南大别变质块体俯冲时的连续性和折返后的断块特征。更多还原

【Abstract】 On the based of petrology,minerals composition and the peak P-T conditions,the eclogites across the South Dabie can be divided into three types of eclogites:①ultrahigh-pressure(UHP) eclogites;②high-ultrahigh pressure(HP/UHP) transition eclogites;③high-pressure(HP) eclogites.The P-T conditions for these eclogites are:T=570 ℃~680 ℃,P=2.00 GPa~2.40 GPa;T=650 ℃~810 ℃,P=2.70 GPa~3.20 GPa;T=760 ℃~980 ℃,P=3.50 GPa~4.00 GPa,respectively,and show that that these eclogites have been formed in different metamorphic environments.The HP/UHP transition eclogites have been discovered in this investigation,and display the characteristics of high-ultrahigh pressure transition metamorphism in the respects of texture,composition of minerals.This type of eclogites explains the coherent nature of the Southern Dabie during subduction and its fault terrane during exhumation.更多还原