辽宁北部秀水盆地白垩系义县组泥岩地球化学特征及地质意义

沉积岩的地球化学特征蕴含了大量的地质信息,对于沉积环境的重塑及物源研究具有重要意义。通过对辽宁北部秀水盆地秀D1井义县组泥岩样品常量、微量及稀土元素等地球化学特征的研究表明:泥岩样品轻稀土元素富集,重稀土元素亏损严重,配分曲线"右倾",可见中等Eu负异常和微弱的Ce负异常,指示稳定的上地壳物源注入。盆地北东—东部的侏罗系、二叠系酸性侵入岩与义县组沉积岩具有较好的亲缘性,可能为其主要物源,源区构造背景主要为活动大陆边缘。B、Sr/Ba、La_N/Sm_N、V/(V+Ni)、Fe²⁺/Fe³⁺、Cu/Zn及Ce_anom等地球化学指标表明义县组沉积时期为淡水环境,古沉积环境为深水还原环境。

Geochemical Characteristics of the Cretaceous Yixian Formation Mudstones in Xiushui Basin of Northern Liaoning and Their Geological Significance

The geochemical characteristics of sedimentary rocks contain a large amount of geological information, which is of great significance for restoring the sedimentary environments and the provenances. Through the analysis on geochemical characteristics such as major, trace elements and REE of mudstone samples of the Yi-xian Formation from Well Xiu-D1, the results show: REE in mudstones are enriched of LREE with a deficit of HREE. The REE patterns incline to the right, with slightly negative Ce anomalies and moderately negative Eu anomalies, indicates stable provenance input from upper continental crust. The acidic intrusive rocks of the Jurassic and Permian in the northeast-east part of the basin have a great affinity with sedimentary strata of the Yixian Formation,so acidic intrusive are highly likely to be provenance of sedimentary strata. The tectonic setting of provenance area is mainly active continental margin. The geochemical indicators such as B, Sr/Ba, La_N/Sm_N,V/(V+Ni), Fe²⁺/Fe³⁺, Cu/Zn and Ce_anom indicate that the Yixian Formation was deposited in fresh, deep water with a reductive environment.