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建平变质杂岩是辽宁西都太古代最下部地质单元,是华北地台北缘麻粒岩相带的重要组成部分。它由少量连续性很差的表壳岩及大量的TTG岩石和其他深成侵入体组成。采用单颗粒锆石Pb蒸发法对其中的TTG岩石及其他侵入岩进行了年龄测定。结果表明:本区TTG花岗质岩浆约于2521Ma开始活动,并于2500Ma左右达到高峰,形成了大量的TTG质侵入体(包括部分喷出岩);紧随其后,本区发生强烈的高级变质变形事件,此事件约于2483~2490Ma达到高峰,使得已形成的岩石变成麻粒岩、紫苏花岗岩及斜长紫苏花岗岩等;于2472Ma就位的与退变质作用有关的后构造花岗岩标志着本区高级变质变形事件的结束。据此,可以推测建平变质杂岩可能形成于陆块形成后不久即发生大陆碰撞和地壳加厚的晚太古活动大陆边缘的环境中。
The Jianping metamorphic complex is the lowest geological unit of the Archean Archean in Liaoning and is an important part of granulite facies belt along the northern margin of North China. It consists of a small number of poorly continuous case rock and a large number of TTG rocks and other deep invasion intrusion. The single-particle zircon Pb evaporation method was used to determine the age of TTG rocks and other intrusive rocks. The results show that the TTG granitoids in this area began to be active at about 2521Ma and peaked at about 2500Ma, forming a large number of TTG intrusions (including some of the expelled rocks); followed by a strong high level Metamorphic deformation events, the event peaked at about 2483 ~ 2490Ma, making the rock has become a granulite granulite, peridotite and plagioclase peridotite granite, etc.; in 2472Ma situ metamorphism retrograde metamorphism of granite Marking the end of the high-grade metamorphic deformation events in this area. Accordingly, it can be speculated that the Jianping metamorphic complex may be formed in the environment of the continental margin of the Late Archean event that occurred shortly after the formation of the landmass, ie, the collision of the mainland and the thickened crust.