中国地质调查2019，Vol.6Issue(2)：76-86,11.DOI:10.19388/j.zgdzdc.2019.02.09
四川盆地北部早白垩世剑门关组泥质岩地球化学特征及其地质意义
Geochemical characteristics and geological significance of argillaceous rocks of Early Cretaceous Jianmenguan Formation in Northern Sichuan Basin
摘要
Abstract
The Early Cretaceous Jianmenguan Formation is a good formation to study the sedimentary environment evolution in Northern Sichuan Basin. The systematical study on its geochemical characteristics is significantly important for studying the provenance, tectonic background, ancient weathering and paleoenvironment of Early cretaceous Jianmenguan Formation. In this paper, the geochemical characteristics of major elements, trace elements and rare earth elements (REE) of the argillaceous rocks of Jianmenguan Formation were systemically analyzed. The results show that the argillaceous rocks of Jianmenguan Formation are rich in CaO, MgO, lack Al2O3, Fe2O3, K2O, Na2O, TiO2, P2O5, MnO, are rich in Cr, Cs, V, and lack Sr, Nb, U, Hf. The total amount of REE (∑REE) ranges from 164.96×10-6 to 234.35×10-6. LREE/HREE is in the range of 11.77～15.87. The fractionation between LREE and HREE is obvious, and LREE content is higher than HREE, with a weak positive Eu anomaly. Based on the analyses above, Jianmenguan Formation is recycling sedimentary rocks from the same sources. Its source rocks are sedimentary rocks, and it may be rich in europium-rich minerals such as plagioclase and barite. The source rocks underwent moderate chemical weathering before sedimentation and K-metasomatisim during the weathering process. The climate during the sedimentary period of Jianmenguan Formation was warm and humid. Tectonic evolution characteristics of the source area appeared to have a transformation from the continental margin to the continental island arc.关键词
四川盆地/早白垩世/剑门关组/地球化学特征/构造背景Key words
Sichuan Basin/Early Cretaceous/Jianmenguan Formation/geochemical characteristic/tectonic setting分类
天文与地球科学引用本文复制引用
徐刚,王越,刘子畅,吕行,高淑芳..四川盆地北部早白垩世剑门关组泥质岩地球化学特征及其地质意义[J].中国地质调查,2019,6(2):76-86,11.基金项目
中国地质调查局"乌蒙山区地质矿产综合调查(中国地质科学院矿产综合利用研究所)(编号:DD20179222)"项目资助 （中国地质科学院矿产综合利用研究所）
