| 南海北部陆缘张裂--岩石圈拆沉的地壳响应 |
| |
| 作者单位： | |
| |
| 基金项目： | 中国科学院南海海洋研究所边缘海地质与古环境开放实验室基金 |
| |
| 摘 要： | 南海北部陆缘在中生代晚期曾形成宏伟的华夏陆缘造山带。火成岩岩石学、岩相古地理学和地球物理学证据显示，该造山带不仅具有巨厚(50～60 km)的陆壳，而且还有巨厚(160～180 km)的岩石圈根，在地势上曾出现过高3 500～4 000 m 的华夏山系。陆缘裂陷盆地的形成发育历史、地壳-岩石圈深部结构、火成岩地球化学特征及理论计算均表明，南海北部陆缘从晚白垩世以来发生的张裂作用起始于华夏陆缘造山带的拉伸塌陷，岩石圈拆沉是南海北部陆缘张裂的重要的引发机制。因此，南海北部陆缘张裂既不同于弧后扩张，也不受控于大西洋式的海底扩张，而是该区大陆构造演化和深部壳幔相互作用的结果。
|
| 关 键 词： | 拉伸塌陷 岩石圈拆沉 南海北部 华夏陆缘造山带 |
CONTINENTAL MARGINAL RIFTING ALONG THE NORTHERN SOUTH CHINA SEA：THE CRUSTAL RESPONSE TO THE LOWER LITHOSPHERIC DELAMINATION |
| |
| Abstract: | There was an orogenic belt called the Cathaysian continental marginal orogenic belt in late Mesozoic along the present northern margin of the South China Sea．Evidences of igneous petrology，paleogeography and geophysics showed that there was not only continental crust of huge thickness （50～60 km），but also a very thick lithospheric root（160～180 km）beneath the orogenic belt．A mountain range，3 500～4 000 m high－the so-called Cathaysian mountain system－was once formed in this region．According to the data of the formation and development of the rifting basins，the deep structures of the crust and the lithosphere，the geochemical characteristics of igneous rocks，and the theoretical calculation，it was reflected that the continental marginal rifting beginning at late Cretaceous along the northern South China Sea was derived from the extensional collapse of the Cathaysian continental marginal orogenic belt，and the lower lithospheric delamination was an important initiative mechanism．Therefore，the continental marginal rifting along the northern South China Sea was different from the back-arc spreading caused by subduction of oceanic plates；and it was not controlled by the Atlantic-type seafloor spreading either．In fact，it was a result of the continental tectonic evolution and the deep crust-mantle interactions beneath this region． |
| |
| Keywords: | |
| 本文献已被 万方数据 等数据库收录！ |
