长乐—南澳变质岩带形成的大地构造背景与变质幕

GEOTECTONIC BACKGROUND AND METAMORPHIC PHASES OF THE FORMATION OF THE CHANGLE-NANAO METAMORPHIC BELT

在充分考虑区域地质资料的基础上，研究该变质岩带形成的大地构造背景、变质幕和原岩层位后认为：变质带是在陆上无海浸“干造山”的大地构造环境下形成的；存在晚侏罗世的第Ｉ变质幕和早中白垩世之交的第Ⅱ变质幕，其分别与华南燕山造山运动幕Ｉ—Ⅱ和幕Ⅲ同步；长乐－南澳断裂带南东的变质岩带的原岩层位包括下古生界和下白垩统（南园组），可能还包括上三叠统至侏罗系（文宾山组－梨山组）、上古生界和下三叠统．

The chief purposes of the present paper are to discuss the geotectonic background,the metamorphic phases and the protolith horizons of the formation of the metamorphic belt on the basis of emphasizing sufficiently regional geological data. The conclusion is reached. (1) The metamorphic belt was formed under the“dry orogenic”continental geotectonic environment without ingression. (2) There were two metamorphic phases, phase 1 of the Late Jurassic and phase 11between the Early and Middle Cretaceous. The two phases were synchronous respectively with phase 1-11 and phase 111 of the yanshan orogenies of South China. (3) The protolith horizons of the metamorphic belt to the southeast of the Changle-Nanaao fault belt include Lower Paleozoic and Lower Cretaceous (Nanyuan Formation) and probably Upper Triassic-Jurassic (Wenbinshan Formation-Lishan Formation) and Upper Paleozoic-Lower Triassic.