珠江口盆地番禺低隆起文昌组断裂活动性特征及其对沉积的影响

珠江口盆地番禺低隆起具有文昌组地层沉积,而断裂活动对文昌组沉积和沉积相展布有重要影响。基于断层活动速率方法,对文昌组控洼断裂活动性特征进行定量研究; 结合沉降速率分析,对控洼断裂活动性强度及断面样式与沉积相展布进行相关性分析。结果表明:当活动速率大于100 m·Ma^-1时,断裂控制中深湖相沉积; 当活动速率小于100 m·Ma^-1时,断裂控制中深湖相沉积边缘或三角洲相及滨浅湖相; 中央隆起带文昌组控洼断裂活动性和珠Ⅰ坳陷文昌组具有很强的正相关性; 控洼断裂的活动性差异控制着沉降中心的发育; 不同断裂构造样式对沉积体系的发育也有一定控制作用,板式断裂控制的沉降中心靠近断裂边缘,而铲式断裂控制的沉降中心则更靠近盆地中心; 深入分析断层活动速率大于100 m·Ma^-1且控制文昌组中深湖相的区域,可能会发现油田。

Characteristic of Fault Activity in Wenchang Formation of Panyu Low Uplift,Pearl River Mouth Basin and Its Influence on Sedimentation

There is Wenchang Formation in Panyu Low Uplift of Pearl River Mouth Basin, and fault activity has an important influence on sedimentation and distribution of sedimentary facies of Wenchang Formation. Based on fault activity rate method, activity characteristic of fault controlled in Wenchang Formation were analyzed quantificationally; combined with sedimentation rate analysis, activity intensity of fault controlled was calculated, and the correlation of fracture type and distribution of sedimentary facies was discussed. The results showed that fault controlled the deposition of middle deep lacustrine facies when activity rate was more than 100 m·Ma^-1; fault controlled the margin of deposition of middle deep lacustrine facies or delta facies and coastal shallow-lake facies when activity rate was less than 100 m·Ma^-1; the correlation of activities of faults controlled in Wenchang Formation between central uplift belt and Zhu I Depression was positive; the difference of activities of faults controlled contained the development of subsidence center; the development of sedimentary system was contained by different types of fault structure in a certain extent, subsidence center contained by slab rupture was near the margin of fault, and that contained by shovel rupture was near the center of basin; the area, in which activity rate of fault was more than 100 m·Ma^-1 and the middle deep lacustrine facies in Wenchang Formation was controlled, was favorable to explore the oil.