收稿日期: 2013-01-25
修回日期: 2013-04-17
网络出版日期: 2013-10-10
基金资助
国家自然科学青年基金项目(编号:41102100);国家科技重大专项(编号:2001ZX05023-001-008);中央高校基本科研业务费课题(编号:2010QNA52)联合资助
Distribution Characteristic and Geological Significance of Rare Earth Element in Mudstoneof the Lower Permian Shanxi Formation in the South of Yanchuan Area,Ordos Basin
Received date: 2013-01-25
Revised date: 2013-04-17
Online published: 2013-10-10
为了研究延川南地区下二叠统山西组泥岩稀土元素的分布特征及其地质意义,采用ICP-MS对研究区30个泥岩样品进行了稀土元素分析。研究表明:泥岩稀土元素的总量较高(93.80~746.47μg/g),ω(LREE/HREE)(1.28~9.97)及(La/Yb)N(1.97~28.78)等比值显示轻重稀土分异明显;∑REE与Ti、Ni、Pb、Rb、Ga、Cr、Zn等外源元素相关性很好,而与Mn、Zn等反映海相环境元素的相关性不明显,揭示了研究区泥岩中REE主要来自陆源碎屑矿物的供给。Ceanom(-0.089~0.138,均大于-0.10)、δCe(0.91~1.35,平均为1.09)指示了泥岩样品均处于缺氧环境下。稀土元素的分布模式和(La/Yb)N—∑REE图显示了母岩主要为花岗岩和沉积岩,并可能为多源型。并且分析结果显示了研究区物源来自于研究区北部并可能为活动性大陆边缘抬升基底物源兼有少部分大陆岛弧切割的岩浆弧物源。层序界面附近的∑REE、(La/Yb)N、δCe、V/(V+Ni)、V/Cr等微量及稀土元素参数的异常波动面与层序界面(SB1、SB4)存在一定程度的对应关系。
谢国梁,沈玉林,魏展航,张 虎,袁学旭 . 鄂尔多斯盆地延川南地区下二叠统山西组泥岩稀土元素特征及地质意义 [J]. 天然气地球科学, 2013 , 24(5) : 991 -998 . DOI: 10.11764/j.issn.1672-1926.2013.05.991
Through ICP-MS analysis,measurements of rare earth element and trace element are conducted by using 30 mudstone samples in the Lower Permian Shanxi Formatio,south of Yanchuan area,for the research on REE geochemical characteristics and its geological application.The result shows that the amount of ∑REE of mudstone (93.80 to 746.47×10-6) is high.The ratios of w(LREE/ HREE) (1.28 to 9.97) and (La/Yb)N (1.97 to 28.78) show that the differentiation of LREE and HREE is significant.The correlation between ∑REE and external elements,like Ti,Ni,Pb,Rb,Ga,Cr,Zn,is very good,while the correlation between ∑REE and the marine elements,like Zn and Mn,is not obvious,which indicated that REE is mainly supplied by terrigenous minerals.The Ceanom(-0.089-0.138,more than -0.10)and δCe(0.91-1.35,average 1.09) show that the water environment in the study area in Shanxi Formation is anoxic reduction.The distribution patterns of REE and ∑REE-(La/Yb)N diagram show that the source rocks of samples mostly consist of granite,sedimentary rock and may be multi-source.And analysis result shows that the direction of source is coming from the north of the studied area,which may be the active continental margin uplift basement sources and a small part of continental island arc magmatite provenance.Moreover,there is a relationship between the sequence boundaries (SB1,SB4) with the abnormal surfaces of ∑REE,(La/Yb)N,δCe,V/(V+Ni),V/Cr trace and REE geochemical characteristics near the sequence boundaries.
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