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大别山超高压变质岩中发现了一系列退变质显微构造,其主要类型有:①由于出溶而产生的定向性包裹物;②由于多型转变而产生的假像替代;③固→固反应产生的冠状体;④涉及流体的退变质反应产生的冠状体或后成合晶。借助显微构造关系,可以建立超高压变质岩的退变质演化阶段,从而构筑其PT演化趋势、识别出碰撞造山和超高压变质峰期之后的两阶段隆升历史:早期为“挤出”作用诱发的近等温减压退变质;晚期则是地壳伸展体制下的退变质,俯冲板片的断离,软流圈上涌,所诱发的部分熔融,降低岩石圈密度导致地壳规模的伸展与超高压变质岩的进一步隆升。最后,本文提出了超高压变质岩形成和折返的3阶段发展的模式。
A series of retrogressive microstructures have been found in the UHP metamorphic rocks in the Dabie Mountains. The main types are: ① directional inclusions due to dissolution; ② pseudomix due to multi-type transition; ③ solid → solid reaction Generated corpus; ④ involved in the fluid degeneration reaction produced coronal or after into the crystal. Based on the microstructure relationship, the retrogressive metamorphic stage of UHPM metamorphic rocks can be established to build up its PT evolution trend and identify the two-stage uplift history after collision orogeny and UHPM metamorphism: the early stage of “extrusion” Inducing nearly isothermal decompression degeneration; late crustal extension system under the degeneration, subduction slab off, asthenospheric upwelling, induced partial melting, reducing lithosphere density lead to crustal scale and super Further uplifting of high-pressure metamorphic rocks. Finally, this paper presents a three-stage development model for the formation and reenforcement of UHP metamorphic rocks.