渭河盆地新生代沉积速率特征与主控因素分析  

Characteristics and Main Controlling Factors of Sedimention Rate of Cenozoic in Weihe Basin

作　　者：张梦婷[1] 李红[1] 李文厚[1] 白金莉 张倩 王晓晨[1] 祁凯[1] Zhang Mengting;Li Hong;Li Wenhou;Bai Jinli;Zhang Qian;Wang Xiaochen;Qi Kai(State Key Laboratory of Continental Dynamics,Northwest University,Xi＇an 710069,China)

机构地区：[1]西北大学大陆动力学国家重点实验室,西安710069

出　　处：《地质科技情报》2018年第4期74-82,共9页Geological Science and Technology Information

基　　金：国家自然科学基金项目(41330315;41630312);中国地质调查局地质调查项目(12120114009201);地质矿产调查评价项目(121201011000150014)

摘　　要：为了研究渭河盆地新生代沉积速率特征与成因,系统收集、整理了研究区已有的重力和磁力资料,结合地震、地质、钻井等研究成果,分析了新生代各期沉积速率变化,探讨了盆地内新生代各期沉积速率与盆内基底、断裂、周缘构造的关系。研究表明,中新世,西安凹陷沉积速率较大,几乎是固市凹陷的2倍,沉积速率最大处位于渭深10井附近,约为93m/Ma;上新世,西安凹陷沉积速率仍较固市凹陷大,二者的沉积速率最大处分别为1 800,1 400m/Ma;第四纪三门期,盆内沉积速率逐渐变缓,沉积速率最大处位于固市凹陷内,约为380m/Ma;秦川期,盆地整体沉积速率明显加快。新生代西安凹陷沉降中心变化不大,主要位于户县以北地区,而固市凹陷沉降中心多变,主要位于华县和临潼以北地区,沉降中心整体偏南。沉积速率的变化受多种因素控制,古近纪,盆地周缘板块运动导致地壳加厚及深部地幔对流对盆内沉积速率影响较小;新近纪早中新世,受青藏高原快速隆升影响,渭河盆地沉积速率显著增大;晚中新世,秦岭北缘大型正断层活动导致渭河盆地发生大规模的沉降和扩展;上新世到第四纪,盆内沉积速率受秦岭山脉和渭北隆起共同作用。In order to study the characteristics and genesis of the sedimentation rate of the Cenozoicin Weihe Basin,this paper systematically collected and neatened the gravity and magnetic measurement data.Based on the data and the seismic,geology and drilling results,the paper analyzes the changes of sedimentation rate of each stage of Cenozoic,and discusses the relationship between the sedimentation rate and basement,fault and peripheral structures.The results show that during the Miocene,the sedimentation rate of Xi′an Depression was nearly twice as great as that of the Gushi Depression,and the fastest placeis near Well Weishen 10,which is about 93 m/Ma.During the Pliocene,the sedimentation rate of Xi′an Depressionwas a little higher than that of the Gushi Depression.In Sanmen period of the Quaternary,the sedimentation rate became slow and the fastest rate was found in Gushi Depression,which was 380 m/Ma.In Qinchuan period,the sedimentation rate of the whole basin was nearly three times as fast as that in the Sanmen period.The center of subsidence of Xi′an Depression in the Cenozoic changed little,mainly located in the north of Huxian City.However,the center of subsidence of Gushi Depression is changeable,but mainly located in the north of Huaxian and Lintong.During the Paleogene,periphery plate movements resulted in the thickening of the crust and the convection of the deep mantle,which has little influence on the sedimentation rate in the Weihe Basin.From the Early to the Middle Miocene,the rapid uplift of the Qinghai Tibet Plateau increased the sedimentation rate significantly in Weihe Basin.In the late Miocene,the activities of the large normal faults of the northern margin of Qinling Mountains led to the settlement and expansion of the Weihe Basin.From Pliocene to Quaternary,the sedimentation rate was controlled by the Qinling Mountains and Weibei uplift.

关 键 词：渭河盆地 新生代 沉积速率 沉积构造演化 主控因素 

分 类 号：P618.130.2[天文地球—矿床学]