中国超高压变质岩十五年研究进展

摘要

Studies on the ultra-high pressure metamorphic (UHPM) rocks from China started in 1980s. Progresses so far made in the field could be summarized as follows.① The Dabieshan-Su-Lu UHPM belt has been well-known since many new outcrops of UHPM rocks were found；② Mineralogical evidences indicate that the continental crust rocks with low density could subduct down to depth of >200 km and undergo UHPM；③ UHPM rocks from the Dabieshan-Su-Lu area were dated as early Mesozoic when the Yangtze Craton subducted northward beneath the Sino-Korean Craton； ④ Fluids were not active and oxygen isotope composition of meteoric water could be preserved during UHPM process, as is evidenced by O, C, and H isotope data； ⑤Multistage models were suggested to explain the exhumation of the UHPM terrain. Some hotly debated issues were summarized.%本文对20世纪80年代以来中国超高压变质岩研究的历史做了简要回顾，列举了该领域的5项重要进展，即：①发现了大批超高压变质岩，使中国的大别山-苏鲁超高压变质岩带成为世界之最；②通过细致的矿物学研究，确认低密度的陆壳岩石可以被俯冲到地下200多公里深处，经历超高压变质作用；③多种同位素体系定年结果表明，大别山-苏鲁超高压变质作用是在中生代早期扬子板块俯冲到中朝板块之下时发生的；④对超高压变质岩中O、C、H等同位素的研究进一步表明，超高压变质作用过程中并无大规模流体活动，大气水的O同位素成分可被带到地幔深处而不改变；⑤通过对岩石学、矿物学、年代学、构造地质学、地球物理学等多学科资料的综合研究，提出了超高压变质地体的多阶段折返模式。文中对目前超高压变质岩研究中的几个争论焦点做了归纳。