中扬子晚二叠世沉积特征及古地理演化

Sedimentary characteristics and palaeogeography evolution in the Late Permian of middle Yangtze area

通过剖面实测、岩相及沉积相分析,中扬子区晚二叠世主要发育碳酸盐岩开阔台地沉积、陆棚沉积及盆地沉积,吴家坪期以浅海相沉积为主,深水盆地范围较小,长兴期发育台地相及盆地相,深水盆地范围变大,研究区晚二叠世的沉积主要受南秦岭海活动控制和盆地演化影响,沉积分异在晚二叠世较发育。古地理演化表明,吴家坪期中扬子北缘为深水盆地沉积,中扬子克拉通主体开阔台地沉积与陆棚沉积并存,鄂西海槽范围缩小,变为孤立海盆;长兴期海侵加剧,中扬子南部为浅海台地沉积,北缘为欠补偿深水盆地沉积且范围进一步扩大,长兴晚期达到高潮,中扬子变为克拉通边缘盆地。

By use of profile measuring, lithofacies and sedimentary facies analysis in the middle Yangtze, Late Permian mainly developed open platform, shelf and basin, Wuchiapingian developed shallow marine sediments, deep-water basin range is small, Changxing developed platform and basin facies, deep-water basin range is expanding. Sedimentary of the Late Permian is controlled by the activities of the south Qinling sea, an obvious sedimentary facies differentiation occurred during Late Permian, which is controlled by basin evolution. Palaeogeographic evolution show that the northern margin of the middle Yangtze Wujiapingian is deep basin, in the main middle Yangtze craton open platform developed, western Hubei trough is an isolated basin; Changhsingian transgression intensified and reach a climax in late Changxingian,the northern margin of the middle Yangtze is deep basin and the scope further expand,the Yangtze craton come into craton margin basin.