变质核杂岩研究进展、基本特征及成因探讨

本文对比了国内外变质核杂岩的基本特征后，重点探讨了几个问题：变质核杂岩发育的构造位置，既有如科迪勒拉变质核杂岩的陆缘冒地斜中心的，又有大量是陆内的。它们的基本结构更普通的是三层式，即在核杂岩和上部不变质的以发育正断层为特点的盖层之间，通常发育一套以浅变质的、发生过强烈近水平剪切所致的韧性流变的中间层状岩系；从韧性流变层的不均匀分布，反映出地热状态的横向不均一性；变质核杂岩的几何学、运动学、热状态及岩浆作用和变质作用等表明，幔源热隆、地壳的热软化、重力上浮及水平应力的联合作用可能是其隆升的原因。

AN OVERVIEW OF METAMORPHIC CORE COMPLEXES───CHARACTERISTICS AND ORIGIN

Comparing the characteristics of metamorphic core complexes(MCC)of Chinaand abroad,several points have been emphasized:(1)The tectonic setting of MCC,thereare two kinds of MCC,located on the margin of cratons,such as Cordilleran MCC,orwithin cratons,such as most MCC found in the North China craton. (2)The MCC arecharacterized by three-layer configuration, instead of two-plate mode suggested for thecordilleran MCC,In addition to the metamorphic core and unmetamorphic cover plate,there is an intermediate ductile slab characterized by non-coaxial ductile flow of low-grademeta-sedimentary sequnces,especially in the older MCC, such as Mesozoic MCC in Chi-na.(3)Horizontal heterogeneous distribution of intermediate ductile flow slab indicatesthe lateral inhomogeneity of the thermal state in the crust.(4) From the geometry,dy-namics,thermal state,magmatism and metamorphism of MCC,it is suggested that a com-bination of heating from mantle,thermal-induced softening of the crust,buoying of theheating core and horizontal shear stress may be the cause of the uplift of MCC.