摘要
文中进行了中国西北地区早—中侏罗世盆地的原型分析 ,着重阐述 3点 :( 1)根据盆地构造特征 ,将中国西北地区早—中侏罗世盆地划分为 :缓断面伸展断陷盆地、陡断面伸展断陷盆地、克拉通内盆地和克拉通周边盆地 4种类型。 ( 2 )这 4类盆地分布于不同的前侏罗纪构造背景之上。第Ⅰ类和第Ⅱ类伸展断陷盆地位于印支晚期造山带和印支晚期复活的古生代造山带 ,它们系造山带伸展垮塌作用的产物。第Ⅲ类克拉通内盆地分布于克拉通块体内部 ,它们具有冷的刚性岩石圈 ,其古地温梯度达不到使岩石圈弱化和产生伸展断陷盆地的临界值。第Ⅳ类克拉通周边盆地位于克拉通和造山褶皱带之间 ,这类盆地的古地温梯度刚达到形成伸展断陷盆地临界值 ,在应变速率低的情况下造成不对称的宽阔凹陷。 ( 3)由于这 4类盆地的地温梯度、演化和改造程度不同 ,它们的含油气远景差别很大 ,其中以克拉通周边盆地最有希望。
Prototype analysis of J 1-2 basins in northwestern China is discussed. Several points have been emphasized.(1)Based on structural characteristics of J 1-2 basins in northwestern China, these can be divided into four types: extensional faulted depression with low angle boundary fault;extensional faulted depression with high angle boundary fault; intracratonic basin and craton marginal basin. (2)These basins were developed on different Pre Jurassic tectonic settings.The extensional faulted depressions were distributed on Indochina orogenic belt and rejuvenated palaeozoic orogenic belt during Indochina epoch.In these orogenic belts lithosphere had been suffered extensional collapse during J 1-2 epoch. The cratonic basins were located on interior of craton block with cool and rigid lithosphere, palaeogeothermal gradient of these cratonic basins is low and not reached a critical value, above which lithosphere weakening and extensional faulted depression may take place. The craton marginal basins were situated between craton and orogenic belt. In these regions its palaeotemperature gradient just reached the critical temperature value because of slower strain rates. (3) Due to the difference in geothermal gradient,basin evolution and modification among the four types of basins,oil and gas assessment may differ greatly among various type of basins, of which the craton marginal basins are most perspective.
出处
《地学前缘》
EI
CAS
CSCD
2000年第4期459-469,共11页
Earth Science Frontiers
基金
中国石油天然气集团公司"九五"油气勘探科技工程资助项目!(970 2 0 0 72 6 )
关键词
盆地原型
含油气盆地
分布
克拉通周边盆地
侏罗纪
basin prototype
extensional faulted depression with low angle boundary fault
extensional faulted depression with high angle boundary fault
intracratonic basin
craton marginal basin