胶莱盆地构造应力场特征及数学模拟

/ FEATURES OF TECTONIC STRESS FIELDS IN JIAOLAI BASIN/

对胶莱盆地露头区及覆盖区断层性质和褶皱形态进行了分析，对露头区各地层的发育节理进行了统计解析。胶莱盆地在发展演化过程中主要经历了四期构造应力场的变化：第一期为早白垩世早期莱阳组（Ｋ１ｌ）沉积期间，为北北西向挤压应力场；第二期为青山组（Ｋ１ｑ）沉积期间，为近东西向拉伸；第三期即王氏组（Ｋ２ｗ）沉积期间，为北西南东向挤压；第四期即在王氏组沉积以后，胶莱盆地受北东向挤压。与上述四期应力场变化相对应，由盆地中发育的地层、火山活动和构造特征可以看出，胶莱盆地是在白垩纪发育起来的一个拉分盆地，经历了４个发育阶段，即莱阳组沉积期间的初始拉分阶段、青山组沉积期间的拉分间歇阶段、王氏组沉积期间的后续拉分阶段和王氏组沉积以后的挤压隆起萎缩发育阶段。在此基础上，设计了４个地质模型，用有限单元法对盆地演化过程中的四期应力场做了数学模拟分析。

The features of faults and joints in outcrop and subsurface folds of Jiaolai basin are analyzed. The basin underwent four stages of tectonic movements: (1) Compression in NNWSSE druing the deposition of Early Cretaceous Laiyang formation; (2) Extension in EW during the depression of Early Cretaceous Qingshan formation; (3)Compression in NWSE during the deposition of late Cretaceous Wangshi formation; (4)Compression in NESE after the deposition of Wangshi formation. The tectonic stress fields and the activities of strata and volcanic show that Jiaolai basin is a pull apart basin developed in Cretaceous period. The basin underwent four development steps responding to the above four stages, including initial pull apart, intermittence of pull apart, follow up pull apart and decline. Four geological models are constructed, and the four periods of tectonic stress fields are numerically modelled with finite element method.