新疆南部奥陶纪库鲁克塔格海槽浊流沉积

ORDOVICIAN TURBIDITY DEPOSITS IN KULUKETAGE TROUGH IN SOUTH XINJIANG

胡继宗 周棣康 曹华琦 郝继鹏 朱国贤 秦天西

Hu Jizong Zhou Dikang Cao Huaqi Hao Jipeng Zhu Guoxian Qin Tianxi

库鲁克塔格海槽位于塔里木地块东北缘.奥陶纪浊流沉积见于槽内兴地断裂以南却尔却克山-南雅尔当山一带,残厚1797.3—2761.0m.可分为盆地边缘海底扇和海槽盆地浊积岩两种类型.其中具鲍马层序的归于典型浊积岩,两扇水道沉积的透镜状或块状砂砾岩则属非典型浊积岩.其纵向序列为推进、退复及复合三种.早奥陶世早期为浊流形成的前期沉积,晚期开始浊流沉积,发育为海底扇推进序列,到中奥陶世末以退复序列结束第一浊积旋回;晚奥陶世开始第二浊积旋回,早期为推进—退复复合的海底扇序列,晚期为槽盆浊流沉积.

Kuluketage Trough is located at the northeast margin of Tarim Massif.The turbidity deposits of Ordovician System are found in Qiaoerqiaoke andNanyaerdang Mountains to the south of Xindi fault in the trough and havethe relict thickness of 1797.3-2761.0 m. The turbidity deposits can be divi-ded into marginal submarine fan and trough turbidity. The turbidite with Bou-ma Sequence is typical, whereas the lenticular or massive sandstone andgravelstone of fan channel deposits are not typical. The turbidity depositsare composed of three kinds in vertical-advanced, contracted and complex se-quences. Two complete turbidity cycles were developed in the Ordovician: thefirst one began with the advanced sequence of the submarine fan in the latestage of the Early Ordovician and ended with contracted sequence in the endof the Middle Ordovician;the second cycle which developed in the LateOrdovician began with the complex sequence of the advance-contracted sub-marine fan in the early stage and ended with the trough-basin turbidity inthe late stage.

10.11743/ogg19880415