【摘要】 利用回剥技术对琼东南盆地进行了沉降史计算和分析,主要包括北部坳陷带的崖北凹陷、崖南凹陷,中央坳陷带的乐东凹陷,和南部坳陷带的华光凹陷。按照地震测线的分布和凹陷特征,我们共选取了30口模拟井进行一维沉降史计算,并展示了具有代表性的8口井,分析他们在不同时期的构造沉降速率与总沉降速率。分析结果表明,新生代以来,琼东南盆地主要经历了三个主要的沉降幕:(1)始新世至渐新世,盆地处于裂陷期,构造沉降速率较大,平均为81m.Ma-1,沉降中心位于中央坳陷带。(2)早中新至中中新世,盆地由裂陷期向坳陷期转化,平均构造沉降速率减小至68m.Ma-1;(3)晚中新世以后,盆地进入新一期的沉降阶段,平均构造沉降速率增加至84m.Ma-1;上新世以后,中央坳陷带发生快速沉降,达到了110m.Ma-1。更多还原

【Abstract】 Tectonic subsidence histories of the Yabei,Yanan,Ledong and Huaguang sags in the Qiongdongnan Basin were analyzed by back-stripping technique.One-dimensional tectonic subsidence histories of 30 presumed wells were calculated,8 wells of which were appraised for their tectonic and total subsidence rates.The results show that the Qiongdongnan Basin experienced 3 main subsiding stages in Cenozoic.(1) The first stage was a rifting stage during Eocene and early Oligocene.The average tectonic subsidence rate was 81m·Ma-1 and it decreased from the central depression to the southern depression.The subsidence center was located at the central depression,which was supposed to be controlled by the pre-existing basal fault.The average tectonic subsidence rate was 105m·Ma-1 at the Ledong depression,74m·Ma-1 in the southern depression zone and 59m·Ma-1 at the Yabei depression.(2) In the second stage from early Miocene to middle Miocene,the Qiongdongnan Basin ended rifting and shifted to a depression stage.The average tectonic subsidence rate decreased to 68m·Ma-1.(3) Since middle Miocene,the Qiongdongnan Basin had experienced an accelerated subsidence stage.The average tectonic subsidence rate increased to 84m·Ma-1 in all the presumed wells.It was 90m·Ma-1 in the 5 presumed wells in the connection zone with the Yinggehai Basin,and 73m·Ma-1 in the 3 presumed wells in the northern part of the basin.After Pliocene,the subsidence rate was higher in the northern and central depression zones,with a value of 110m·Ma-1.更多还原