德令哈中生代沉积盆地成因类型及其与南祁连造山带的关系

THE GENETIC TYPE OF THE DELINGHA MESOZOIC SEDIMENTARY BASIN AND ITS RELATIONSHIP WITH THE SOUTH QILIAN OROGENIC BELT

长期以来，对柴达木盆地中生代的大地构造属性一直存在争议．笔者根据柴达木盆地北缘的德令哈盆地中生代盆地充填序列、基底沉降过程和大地构造相分析结果认为，该盆地具有典型的前陆盆地沉积－构造演化特点．（１）二叠（？）一中三叠世发育类复理石盆地组合和早侏罗一早白垩世发育陆相含煤磨拉石盆地组合，构成前陆盆地的“标型”充填；（２）上凸的总沉降曲线反映前陆盆地的发育规律；（３）德令哈前陆盆地的形成说明柴达木板块和华北板块的末次陆一陆碰撞发生在晚三叠世，早侏罗－早白垩世的构造运动则归属于南祁连对柴达木板块的陆内逆冲推覆作用．

here have long been disputes about the tectonic attribution of the Qaidam Mesozoicbasin. In this paper, based on the basin-fill sequences, tectonic subsidence and tectonic factes of the Delingha Mesozoic basin located at the northeastern Qaidam basin, the authorhas come to the following conclusion. Delinghg Mesozoic basin was a foreland basin withcharacteristics of the classic foreland basin's sedi-tectonic evolution. (l) The flysch basin association of Permian (?)-Middle Triassic and the molasse basin association of Jurassic-earlyCretaceous form a sample-fill sequence in the Delingha foreland basin. (2) The up-convexcurves of the total subsidence represent the law of foreland basin evolution, that is Delinghabasin undergone a accelerating subsidence period in the middle Jurassic-early Cretaceous.(3) The formation of the Delingha foreland basin shows that the last inter-continentalgeosyncline (aulucogene?) between the North China plate and the Qaidam plate was foldedduring the late Triassic, and the intra-continenal tectonism in the early Jurassic--the earlyCretaceous could be belonged to the South Qilian foreland thrusting towards Delingha foreland basin.