摘要:
奇尔古斯套组硅质岩SiO2含量较高,Al2O3、TiO2含量变化较大,反映出较多的外来物质的加入;Si/(Al+Fe+Mn)、Al/(Al+Fe+Mn)、MnO/TiO2、Al2O3/(Al2O3+Fe3O2)值较高,反映其为生物化学成因,形成于大陆边缘环境;Fe2O3/TiO2对Al2O3/(Al2O3+Fe2O3)图解同样说明其形成于大陆边缘环境.REE较高,HREE富集不明显,北美页岩标准化后的稀土配分模式曲线较为平坦,向左倾斜不明显,(La/Ce)shale值较低,δCeshale值较高,无明显Ce负异常,反映奇尔古斯套组硅质岩属生物化学成因硅质岩,形成于大陆边缘环境;(La/Ce)shale对Al2O3/(Al2O3+Fe2O3)图解亦说明其形成于大陆边缘环境.微量元素中Hf含量高,而Be、Li、Nb、Rb、Sr、Ta、Th、U、V、Zr含量低;Ba元素含量低;Co、Ni贫富相当,Co/Ni值较高,U/Th值低,说明奇尔古斯套组硅质岩属于正常的生物化学成因的硅质岩.
Abstract:
The cherts of Qiergusitao Formation show the addition of more foreign substances with high content of SiO2,and great transformable content of Al2O3,and TiO2.Also the high ratios of Si/(Al+Fe+Mn),Al/(Al+Fe+Mn),MnO/TiO2,and Al2O3/(Al2O3+Fe3O2) reflect that the cherts of Qiergusitao Formation are the biochemical cherts and formed in a continental margin.Moreover,the Fe2O3/TiO2-Al2O3/(Al2O3+Fe2O3) diagram shows that Qiergusitao Formation formed in a continental margin as well.Meanwhile the cherts of Qiergusitao Formation have high content of REE,unobvious enrichment of HREE,low ratios of(La/Ce)shale,high values of δCeshale and typical NASC-normalized flat REE patterns without visible negative anomaly and visible leaning to the left.Furthermore the characteristics of the lanthanon element show that the cherts of Qiergusitao Formation are the biochemical cherts and formed in a continental margin.In addition,the(La/Ce)shale-Al2O3/(Al2O3+Fe2O3) diagram proves that Qiergusitao Formation formed in a continental margin.And the samples of Qiergusitao Formation have the high content of trance element Hf,low content of Li,Nb,Rb,Sr,Ta,Th,U,V and Zr;unobvious enrichment of Co and Ni,the high ratios of Co/Ni,and low ratios of U/Th.The characteristics of the trace element show that the cherts of Qiergusitao Formation is normal biochemical origin.
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