初论造山带古地理学

造山带古地理学属构造古地理学 ,是造山带地层学的姐妹学科 ,其核心是活动论构造观。简述了造山带古地理学的形成和内涵 ,重点讨论了地质记录已发生移位、歪曲和混杂的造山带地区 (或经造山作用改造的克拉通地区 )正确地进行构造—古地理重建的三个问题 :一是不能用“将今论古”的方法恢复地史期间的隆起区和堆积区 ,地史期间的物源区并非一成不变 ,要充分认识物源供应的多样性和多重性 ;二是沉积相带的展布受区域构造应力场及基底构造格局控制 ,要特别重视边缘相及其物源区的研究 ;三是辨析原生沉积盆地与构造盆地 ,对盆地进行正确的构造复位是古地理重建的基础。

AN APPROACH TO OROGEN-PALEOGEOGRAPHY

Orogen-paleogeography, as a main branch of tectonopaleogeography, is a sister discipline of orogen-stratigraphy, with a key thinking being a tectonic outlook of mobilism. The geological records in the orogenic areas must be unsuccessional timely and displaced, distorted even mixed spatialy. Orogen- paleogeography is supporting a series of methods, such as reparation, correction and restoration, for reasonable palinspastic reconstruction. The core region of orogen is, generally, a structural melange belt, whose tectono-paleogeographic reconstruction needs a special method: to inverse the inversed tectonics. This paper expounded briefly formation and contents of orogen-paleogeography, and discussion centered on three questions. 1)Reconstruction of geohistorical erosion and deposition areas could not use the method "present being a key to past" and the provenance could not be unchangeable during the geohistory, so the diversity and polyfunctionality of provenance should be emphasized. 2) Extension of sedimentary facies belts was controlled by the regional tectonic stress field as well as the basemental structural framework, a study should pay great attention to sediments of marginal facies and its provenances. 3)A protogenous basin or a post basin (structural basin) should be distinguished firstly, because today′s scattered and isolated basins might be resulted from disintegration of a historical large basin, while today′s neighbouring basins linked together might be attached to different basins which once separated far away historically; it was a good scheme of basin restoration that was a foundation for correct palinspastic reconstruction.