辽西兴城曹庄地区早白垩世火山岩地层的划分及对比

发布时间：2018-09-03 20:59

【摘要】：本论文对辽西兴城曹庄地区的早白垩世火山岩地层进行研究,通过野外区域地质调查和实测剖面工作以及室内的综合地层学分析,厘定了岩石地层序列,针对研究区典型的岩石样品进行锆石U-Pb年龄及地球化学测定,并结合老爷庙南沟地区剖面,与义县组层型(阜新-义县盆地马神庙-宋八户剖面)进行区域地层对比。论文的研究内容及成果包括以下几个方面:1.野外工作对研究区进行了大比例尺区域地质调查,通过对SⅠ兴城地区尖山-老滩早白垩世剖面的实测,厘定了研究区早白垩世火山岩的岩石地层序列,通过对其岩石组合特征的分析和整理,将该套地层划分为两个段级岩石地层单元。2.对研究区内的5个典型岩石样品进行锆石U-Pb年龄测定,获得年龄分别为131.5±1.4Ma、126.0±1.2Ma、129.2±1.0Ma、113.3±1.6Ma和112.7±2.6Ma。结果显示,尖山-五里桥采石场一带的岩石样品年龄介于135~120Ma之间,应属义县组;老滩一带的岩石样品年龄较年轻,或为九佛堂组顶部或阜新组同时期的熔岩相。二者呈平行不整合接触,为辽西南部地区早白垩世两期火山活动形成的产物。3.通过对SⅡ新台门盆地白马石地区老爷庙南沟义县组剖面和义县组层型(阜新-义县盆地马神庙-宋八户剖面)的观测,将研究区SⅠ兴城地区尖山-老滩早白垩世剖面(义县组部分)与二者进行对比,结果显示曹庄地区义县组与义县组层型中、下部可对比,白马石地区义县组与研究区义县组下段可对比。4.分别对尖山地区和老滩地区的火山岩样品进行主量元素、微量元素和稀土元素的地球化学测定,结果显示尖山地区岩石样品属高钾钙碱性系列,老滩地区义县组属钾玄岩系列,这与岩浆喷发时的动力条件强弱有关,二者岩浆源区相同,均为壳幔混源形成的产物,形成于板块碰撞后的板内伸展背景下。
[Abstract]:In this paper, the early Cretaceous volcanic strata in Caozhuang area, Xingcheng area, western Liaoning Province, are studied. The sequence of rock and strata is determined through field regional geological survey, measured section work and laboratory comprehensive stratigraphic analysis. Zircon U-Pb age and geochemistry were measured for typical rock samples in the study area and regional stratigraphic correlation was carried out with the stratigraphic type of Yixian formation (Mashenmiao-Songbahu section of Fuxin-Yixian basin) combined with the section of Nangou area of Laoyamiao. The research contents and results of this paper include the following aspects: 1. A large scale regional geological survey was carried out in the study area by field work. The lithostratigraphic sequence of the early Cretaceous volcanic rocks in the study area was determined by measuring the early Cretaceous section of the Jianshan-Laotan area in the S 鈪，

本文编号：2221147