CAJ | 학술논문

为了探讨川西前陆盆地上侏罗统-白垩系的物源属性及源区构造背景,对该区上侏罗统-白垩系泥质岩的稀土元素(REE)地球化学特征进行系统分析,结果表明,构造区及沉积环境对泥质岩的REE特征及其沉积分异作用有一定的控制性.在沉积成岩过程中,泥质岩的REE特征在一定程度上受到沉积作用的改造;泥质岩具有明显的LREE富集、HREE丰度低、负Eu异常以及大多数样品具有较明显负Ce异常的特点;从J_3到K_2,泥质岩均具有较高的REE分异程度,不同阶段的REE平均分异程度相对稳定;泥质岩形成于一种总体偏氧化、局部具还原性质的沉积环境;源区母岩以沉积岩和花岗质岩石为主,也可能有玄武岩成分的混入;源区构造背景主要为大陆岛弧,也有来自被动大陆边缘的物源.
위료탐토천서전륙분지상주라통-백성계적물원속성급원구구조배경,대해구상주라통-백성계니질암적희토원소(REE)지구화학특정진행계통분석,결과표명,구조구급침적배경대니질암적REE특정급기침적분이작용유일정적공제성.재침적성암과정중,니질암적REE특정재일정정도상수도침적작용적개조;니질암구유명현적LREE부집、HREE봉도저、부Eu이상이급대다수양품구유교명현부Ce이상적특점;종J_3도K_2,니질암균구유교고적REE분이정도,불동계단적REE평균분이정도상대은정;니질암형성우일충총체편양화、국부구환원성질적침적배경;원구모암이침적암화화강질암석위주,야가능유현무암성분적혼입;원구구조배경주요위대륙도호,야유래자피동대륙변연적물원.
REE of the Upper-Jurassic and Cretaceous argillaceous rocks from the western Sichuan foreland basin were tested and analyzed, and the geochemical characteristics of REE, sedimentary environments, provenance properties and tectonic settings of provenances of argillaceous rocks from the research area were also discussed. Current study shows that tectonic provinces and sedimentary environments have a control to a certain extent on the REE characteristics and sedimentary differentiation of REE of argillaceous rocks, and that REE characteristics of argillaceous rocks were mainly reconstructed to a certain extent by sedimentation. Although the testing samples present dominantly significant LREE enrichment, low-abundance HREE and negative Eu anomaly, most of them display obviously negative Ce anomaly. Results suggest that all argillaceous rocks have high differentiation degree and stably average differentiation degree from Upper Jurassic to Upper Cretaceous. A sedimentary environmental model characterized by overall oxidation and local deoxidation was suggested for the argillaceous rocks in research area. Source rocks are mainly sedimentary rocks and granitic rocks, probably with a few locally-involved basalt components. Analysis of provenances of argillaceous rocks show that the tectonic setting is mainly continental island arc and partly passive continental margin.