摘要
用板块构造理论对柴达木盆地及相邻地区的地质构造演化进行了论述,并划分出华北板块、塔里木板块、秦祁昆板块与巴颜喀拉-扬子板块四部分,各部分先后于早古生代时期、晚古生代后期及中生代早期由其间发育的深断裂-缝合带相拼接。中新生代时期印度板块向北碰撞、俯冲于西藏板块之下,第三纪中晚期俯冲作用加剧,柴达木地区随着青藏高原整体迅速隆升而陷落,形成了柴达木构造断陷盆地。
In the research work on the sylvite deposits and the forming conditions of rich in K bitternof Chaidam Basin in Qinghai Province, the formation of the basin and the geotectonic evolution of itsadjacent areas need to be studied to supply regional background data for the formation and distributionof the sylvite deposits of the basin. This paper is an initial result of the researches. The Chaidam Basin, a part separated from the Qinling-Qilian-Kunlun palaeo-block, is a micro-continental block in the Qinling-Qilian-Kunlun Plate. The northern part of the Qinling-Qilian-KunlunPlate is adjacent to the Talim Plate and the North China Plate, and the southern part to the Bayankala-Yangtza Plate. All these plates joined with each other by a suture of deep rift-ophiolite (or basic, ultra-basic rocks). In the period of early Palaeozoic Caledonian Movement, the Qinling-Qilian-Kunlun Platewas first joined to the North China Plate along the suture on the northern edge of Hexi Corridor. After-wards, in the later Period of the late Palaeozoic Hercynian Movement, the Talim Plate was joined to theQinling-Qilian-Kunlun Plate and the North China Plate along the suture of the Arjin Mountain. In theperiod of Mesozoic Early Indosinian Movement, the Bayankala-Yangtze Plate was joined to the unitedplates of Talim, Qinling-Qilian-Kunlun and North China along the suture of Xiugou-Maqin. Sincethen, the embryonic form of China's pelaeo-continent was formed. In the period of the HimalayanMovement, owing to the underthrust of the India Plate toward the north, the whole Qinghai-XizangPlateau swiftly heaved, and the Chaidam rift basin was formed due to the dowcast of Chaidam Micro-Continental Block along the southern edge of the Qilian Mountain and the northern edge of the KunlunMountain. Very thick clastic Tertiary terrestrial deposits accumulated within the basin (the thickest de- posit being 9600m). From Epipleistocene to Holocene of Quaternaty, the basin was further developed. The depositioncenter of the basin moved from west to east, and the salt began to form 0.03 Ma ago. Since 0.03 Ma, inthe separted and closed salt lake basin of Charhan, Dayantan and Kunteyi very thick salt deposits, car-nallite and bittern deposits rich in K were formed.
关键词
地质构造
演化
柴达木盆地
板块
Qinghai-Xizang plateau
Chaidam Basin
Plate tectonics
geotectonic evolution
formation of the basin
