渤海湾盆地济阳坳陷第三系火成岩岩石化学特征及成因分析

ANALYSIS ON THE PETROCHEMICAL CHARACTERISTICS AND GENESES OF THE TERTIARY IGNEOUS ROCK IN THE JIYANG DEPRESSION, THE BOHAIWAN BASIN

刘惠民 谢忠怀

LIU Hui-min XIE Zhong-huai

石油大学, 地球资源与信息学院, 山东, 东营, 257061 2. 胜利油田有限公司, 地质科学研究院, 山东, 东营, 257015

Department of Earth Resources and Information, University of Petroleum, Dongying, Shandong 257061, China 2. Research Institute of Geological Sciences, Shengli Oilfield, Dongying, Shandong 257015, China

在进行岩石的化学组成、稀土元素、同位素等分析的基础上,文中探讨了渤海湾盆地济阳坳陷第三系火成岩的岩石化学特征和成因。济阳坳陷第三系玄武岩可分为拉斑系列和碱性系列,碱性系列玄武岩主要为钠质系列,该区第三系玄武质岩浆岩主要为大陆裂谷成因的大陆拉斑玄武岩,玄武质岩浆的喷发深度为150～230km。济阳坳陷火山岩随着层位的变新岩浆分异程度降低,越晚形成的岩浆基本代表原始岩浆,第三系不同层位的玄武岩及其基性侵入岩源区均为上地幔,且侵入岩与火山岩同源,并且在岩浆形成过程中发生过不同源区之间的混合作用,而且熔融程度从古新统到渐新统是逐渐降低,反映出岩浆的地幔源的深度在逐渐加大。这些认识对岩浆岩的油气勘探具有重要的参考意义。

Based on the chemical composition, REE and isotopic analyses of rocks, the petrochemical cha-racteristics and geneses of the Tertiary igneous rock in the Jiyang Depression, the Bohaiwan Basin were discussed. The Tertiary basalt in the Jiyang Depression can be divided into tholeiite and alkali two series. The alkali series basalt was mainly agpaitic series, and the Tertiary basaltic magmatite of this area whose eruptive depth was 150-230km was mainly continental tholeiite of continental rift genesis. The differentiation degree of magma decreased when the horizon of volcanic rock in the Jiyang Depression got newer. The magma formed later basically represented primary magma. The Tertiary basalt of different horizons and its basic intrusive rock had the source areas of upper mantle, and intrusive rock was of same sources with volcanic rock. During the forming process of magma, mixing reaction happened among different source area, and melting degree decreased gradually from the Paleocene to the Oligocene, which suggested that the mantle source depth of magma increased gradually. These cognitions will of important reference significance to hydrocabon exploration in magmatic rock.

中国石化"九五"重点科技攻关项目(P99049).

https://doi.org/10.11781/sysydz200304385