济阳坳陷中、新生代盆地转型期断裂特征及其对盆地的控制作用

Faults and Their Control on the Basin during the Transfer Stage of the Jiyang Depression in the Mesozoic—Cenozoic

本文在定量计算断层活动速率的基础上,结合盆地分析,研究了济阳坳陷中、新生代盆地转型时期(孔店期—沙河街组四段沉积期)的断裂组合特征及断层活动对盆地的控制作用,并对转型机制进行了探讨。研究结果表明:孔店期,济阳坳陷继承了中生代后期的断裂发育特点,盆地格局受NW向断层活动控制,NE(ENE)向断层尚未对盆地发育产生重要影响;沙河街组四段沉积期,NW向断层控制作用减弱,NE(ENE)向断层活动逐渐增强,并开始控制盆地的演化,新生代NE(ENE)向盆地构造格局开始定型;中生代末—新生代初期郯庐断裂活动由左旋走滑到右旋走滑的转变,是济阳坳陷中、新生代盆地转型最直接的原因。

Based on a calculation of the displacing velocity of NW-trending faults and NE-trending faults, and basin analysis, faults and their control on the basin is analyzed, and the transfer mechanism of the Jiyang Depression in the Mesozoic—Cenozoic is discussed. The faults in the Ek stage remained the same features of the late Mesozoic, i.e., the NW trending faults controlled the basin pattern, and the NE(ENE) trending faults had little effect. The control of NW trending faults on the basin became weaker in the Es4 stage, and the activities of NE(ENE) trending faults became stronger. The NE(ENE) trending basin pattern came into being. The transition from sinistral to dextral of the Tanlu Strike-slip Fault in the late Mesozoic to earlier Cenozoic is the main factor that controlled the transfer of the Jiyang basin pattern from NW trending to NE(ENE) trending.