摘要
本文主要对中国自中元古代末晋宁造山运动(1100—880Ma)后震旦纪时期呈现的古构造格局及构造单元,并就各单元特别是扬子地台、东南地槽、及塔里木-华北地台范围的构造-古地理、沉积特征及其演化过程,进行讨论和概括。
In this paper, the late Precambrian tectonic framework and major tectonic units emerged after the Jinning orogeny in China, and the characteristics, tectono-paleogeographic and de-positional evolution processes of individual units, especially of Yangtze platform during Sin-ian period are discussed and elaborated in a broad outline.In Middle Proterozoic, the consolidation and growth of the North China platform deve- loped steadily, while the southern China realm was mainly a geosynclinal mobile belt. At the-end of Middle Proterozoic, the Jinning movement caused a large part of the southern China geosyncline to be closed to form Yangtze platform entering then the time of Sinian period. In this time, the tectonic framework of China was Characterized by the west-east orientation. The major tectonic units in China from north to south were Junggar-Songliao geosyncline, Tarim-North China platform, Kunlun-Qingling geosyncline, Yangtze platform, Southeast geosyncline, Zhangbei (northern Tibet) platform and Himalayan geosyncline.The paleogeographic and sedimentary evolution of China may be divided into Early and Late Sinian stages by the mark of Chengjiang movement. During Early Sinian the Tarim-North China platform was an erosional land. Junggar-Songliao geosyncline and Himalayan geosync-line were geosynclinal seas. Zhangbei platform was a platform land. Kunlun-Qingling geosyncline was a deep marine trough of eugeosynclinal character. The Yangtze platform as a whole was an uplifted land with complicated topography. The Jiangnan belt of Southeast geosyncline was a margin of the Yangtze passive continent.In early Late Sinian there was a stage of wide spread glaciation, while later a stage of normal shallow sea deposition. During the Nanhua Glacial Mega-age the Yangtze platform was all over covered with the continental ice sheet, which had extended to cover the Tarim-North China platform, And the deposition in the Jiangnan belt of Southeast geosyncline was of glacial-marine facies.The Doushantuo marine transgression took place immediately after the ending of the glacial age. Most area of southern China units and the southwestern margin of the North Chinai platform were invaded. The southern Qingling marine trough became a marginal sea of Yangtze platform. The paleogecgraphic aspect of the Yangtze platform in Doushantuo stage was-rather complicated. To the west of the upper Yangtze platform, the Chuan-Dian flat was a shallow depositional area. The Dianzhong swell was an erosional land and northern Guizhou area a closed marine basin. In the eastern part of the upper Yangtze platform and all of the lower Yangtze platform, there was rather obstructd shallow marine area and many phosphate deposits were found.During Dengying stage the marine transgression further expanded. The paleogeographic depositional condition was homogenized everywhere. The Tarim-North China platform became an erosional land. The Yangtze platform was a wide open sea with carbonate flat environment. The Jiangnan belt of Southeast geosyncline was a bathyal basin with diposition of siliceous rocks. The southeastern belt of Southeast geosyncline remained a pretty deep marine-trough with deposition of siliceous shale containing flysch formation.
出处
《地质科学》
CAS
CSCD
北大核心
1991年第4期309-316,共8页
Chinese Journal of Geology(Scientia Geologica Sinica)
关键词
晚前寒武纪
构造
古地理
沉积
演化
Jinning movement, Chengjiang movement, Sinian system, old land, Epi-continental sea, Marine trough
