初论板内造山带

A PRIMARY DISCUSSION ON THE INTRAPLATE OROGENIC BELT

讨论了关于板内造山带含义的不同认识。指出板内造山带是一种特殊类型的造山带，而不是板缘造山带或板间造山带持续发展的结果。简要介绍分别发育在４ 个大陆的不同时代的板内造山带，总结板内造山带在区域大地构造位置、造山带构造格局、构造变形与变质作用、岩浆活动与沉积作用、造山带构造演化等方面与板缘造山带的差异。板内造山带形成于相对较老且强硬的岩石圈板块内部，造山带内部构造单元不具有平行于造山带走向分布的特征，即不具有线状构造格局，构造变形具有地台基底乃至整个地壳卷入的厚皮构造性质，同造山区域变质作用微弱，同造山岩浆活动、沉积作用和构造变形均无极性演化趋势。岩石圈拆沉作用（ｄｅｌａｍｉｎａｔｉｏｎ） 可较好地解释板内造山带的火山活动特征。尽管板块间相互作用（ 俯冲或碰撞）所产生的水平挤压应力似乎更易于阐明板内造山带的收缩变形特征；但是，板块间相互碰撞或俯冲产生的边界应力可否有效地被远程传递，尚有待进一步研究和解决。将板块间相互作用的水平应力场与岩石圈纵向物质与能量调整（ 重力、热力等） 因素作综合考虑。

The different opinions concerning the concept of intraplate orogenic belt are firstly reviewed in this paper. Four continental intraplate orogenic belts are briefly introduced before the discussion on popular features of the intraplate orogen are made. It is stressed that the intraplate orogenic belt is a distinct new type of orogen rather than a successor of an interplate or plate marginal orogenic belt. There are a lot of different distinguishable characters between intraplate orogenic belt and plate marginal orogenic belt no matter what in tectonic settings, tectonic framework within orogen, structural and tectonic deformation, synorogenic metamorphism, magmatism and volcanisms as well as sedimentation, orogenic process et al.. The intraplate orogenic belts are formed within the relatively old, rigid and stable lithospheric plate. They are characterized by the tectonic framework with anastomosed features, rather than linear distribution of tectonic units as those in plate marginal orogen. Basement involved and (or) entire crust involved thick skinned tectonic deformation dominated the intraplate orogenic belt. Synorogenic regional metamorphism in the intraplate orogen is weaker than that occurred within plate marginal orogen. Structural and tectonic deformation, synorogenic metamorphism, magmatism and volcanisms as well as sedimentation don't appear evolutionary polarity in the intraplate orogen. It seems to be that the lithospheric delamination model for the intraplate orogen formation can give a reasonable explanation about the synorogenic magmatism and volcanisms, and the planar differential stress caused by subduction or collision of plates may probably be responsible for the contraction deformation within the intraplate orogen. However, the problem is that if the planar differential stress induced by subduction or collision of plates can be transmitted over far field effectively, i.e.,if it is strong enough to result in intraplate orogenic deformation, it should be resolved before the positive answer is got. A comprehensive united model, in which the stresses induced by plates interaction and the energy (gravity, heat et al.) and material exchanging and adjustment in vertical orientation within lithosphere are involved, is helpful to understand the dynamic process of the intraplate orogeny.