辽河坳陷东部凹陷古近系重矿物分布规律及其指示意义  

DISTRIBUTION OF HEAVY MINERAL AND ITS IMPLICATION TO PALEOGEOGRAPHY ENVIRONMENT OF PALAEOGENE IN THE EASTERN SAG OF LIAOHE BASIN

作　　者：韩作振[1,2] 高丽华[1,2] 杨仁超[1,2] 樊爱萍[1,2] 宋到福[3] 蔡国刚[4] 李春华[4] 陈金勇[1,2] 

机构地区：[1]山东科技大学地质科学与工程学院,山东青岛266510 [2]山东科技大学山东省沉积成矿作用与沉积矿产重点实验室,山东青岛266510 [3]中国地质大学(北京)能源学院,北京100083 [4]辽河油田公司勘探开发研究院,辽宁盘锦124010

出　　处：《矿物岩石》2010年第3期59-68,共10页Mineralogy and Petrology

基　　金：国家自然科学基金(40972043);山东省科技发展计划(2009GG2GC06005);山东省教育厅科技计划(J09LE11)

摘　　要：根据辽河坳陷东部凹陷古近系碎屑重矿物组份及稳定性组合研究,将研究区古近纪构造演化分为稳定重矿物阶段和不稳定-较稳定重矿物阶段。其中,稳定重矿物阶段对应始新世(沙三期),此时,稳定重矿物组合占优势,稳定系数、ZTR指数、稳定重矿物组合锆石和氧化钛矿物平均值分别为80.54%,45.88%,44.1%和14.79%;而不稳定矿物组合和较稳定重矿物组合含量低,指示此期构造活动平缓。不稳定-较稳定重矿物阶段对应渐新世(沙二期—东营期),此期不稳定、较稳定重矿物组合占优势,均值分别为绿帘石20.39%,辉石+角闪石3.87%,石榴石19.48%,说明该时期构造活动强烈。从始新世到渐新世稳定系数和ZTR指数逐渐降低,其所指示的构造运动逐渐增强,沙二期是两期构造运动的重要调整期。重矿物纵向分布规律与辽河坳陷构造演化呈对应关系,稳定重矿物阶段又分为沙三早期构造活动平缓的伸展沉降期和沙三晚期构造运动强烈的上升回返期;不稳定-较稳定重矿物阶段分为沙二期构造运动平缓的伸展沉降期、沙一期构造运动逐渐增强的上升回返期、东营早中期构造相对平缓的伸展沉降期和东营晚期构造活动强烈的右旋走滑期。根据砂岩中自生矿物赤褐铁矿的分析,认为含量较高的沙三上、沙二段、东二段沉积期气候较干旱,而含量较低的沙三下、沙一段以及东三段、东一段沉积期气候湿润。According to the components and stability of the clastic heavy minerals,the tectonic evolution of the studied area can be classified into two stages：the stable heavy mineral period and unstable-stable heavy mineral period.Firstly,the period of the steady heavy mineral corresponds to the Eocene（Es3）,during which the assemblage of stable heavy minerals is dominate,and the average of stability coefficient,ZTR factor,zircon and titania is 80.54%,45.88%,44.1% and 14.79% respectively.While in the unstable and stable stage,the content of heavy minerals are low,indicating a situation of smooth tectonic activity.Secondly,the period of the unstable-stable heavy mineral corresponds to the Oligocene（Es2 to Ed）,during which the assemblage of unstable-stable heavy minerals are domination,and the average content of the epidote,pyroxene＋ amphibole,and garnet is 20.39%,3.87% and 19.48% respectively,indicating a situation of intense tectonic activity.From Eocene to Oligocene,the stable factor and ZTR index were declining gradually,suggesting the increasing of intensity of tectonic movement,and the Es2 being the important tectonic transition.The law of longitudinal distribution of the heavy minerals and the structural evolution of Liaohe Basin are homologous.The stable period can be divided into two stages：the extend-ebbing period of the Lower Es3 with weak to gentle structural activity and the ascend-reversion of the Upper Es3 with intensive structural activity.Unstable-stable period can be divided into the extend-ebbing period of the Es2 with gentle structural activity,the ascend-reversion of the Es1 with intensive structural activity,the extend-ebbing period of the early-mid Ed with gentle structural activity and the clockwise period of the Late Ed with intensive structural activity.According to analysis of hematite and limonite from the sandstone,it is considered that the weather of the depositional stage is dry in Upper Es3,Es2 and Ed2 with higher content of heavy minerals,and moist in Lowe Es3,Es1,Ed3 and Ed1 wi

关 键 词：东部凹陷 重矿物指数 构造意义 走滑反转 古气候 

分 类 号：TE121.3[石油与天然气工程—油气勘探]