华南沿海古夷平面特征及其对新构造运动的反映

Some Charaeteristics of Aneient Perieplains and Its Expresent in Neotectonic Movement Along the Coast of the South China Sea

用模糊数学方法,建立起识别古夷平面的模糊数学模型,编出了全区古夷平面高程等值线图。由资料表明:(1)华南沿海古夷平面分布严格受断裂控制,断块运动是本区新构造运动的显著特征之一;(2)断块抬升有从东往西逐渐变晚的趋势;(3)断块运动受统一应力场支配,早期(渐新世—上新世)主压应力方向为NE—SW,晚期(上新世末—第四纪)则转为NW—SE。

Based on the analysis of strata records, a unified peneplain had been developed along the coast of the South China Sea. However, the peneplain began to be disintegrated in oligocene, resulting in the uplift and formation of ancient peneplains. A fuzzy model that can be used to identify,these ancient peneplains is established in the paper. By using this model ,an ancient peneplain elevation isogram along the coast of the South China Sea has been built up. From the study of the characteristics of the ancient peneplains and the data of geology, geophysics, we draw three conclusions:（1） The distribution of the ancient peneplains is restricted by faults in this area and fault-block movement is a notable characteristics along the coast of the South China Sea. （2）The uplift time of the fault-blocks become late gradually from east to west. （3）Fault-block movement is controlled by the unified regional stress field. The principle compression stress direction was NE--SW during the early neotectonic stage （E3— N2） ,while in the late stage （the end of N2—Q） it’s become to NW—SE.