| 四合屯—大康保地区义县组火山—沉积岩地质特征 |
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| 关键词:geological characteristics volcano-sedimentary rocks Yixian formation |
| 基金项目:中国地质调查局项目“北票、上园、义县、地藏寺等4幅1∶5万区域地质调查(编号J4.1.12) |
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| Geological Characteristics of the Volcano-Sedimentary Rocks of Yixian Formation in Sihetun-Dakangpu Area |
| There are three beds in the volcano sedimentary rocks of Yixian formation in Sihetun Dakangpu area. The lower bed consists mainly of basic and intermediate basic volcanic sedimentary basaltic or basaltic andesite rocks; the middle bed is made up chiefly of intermediate acidic volcanic sedimentary rhyolitic or dacitic rocks; and the upper bed is composed predominantly of the basaltic volcanic basalt and basaltic porphyrite. Being products of the volcano inactive period, the thin beds of tuffite, tuffaceous siltstone and calcareous shale usually occur at the bottom of lava or agglomarate. Field mapping and comprehensive study also show that there are Palaeo vertebrate fossils (mainly of Psittacosaurus) in the tuffite of the lower beds of Yixian Formation, and that "Jehe Biota" (including precious birds) fossils rich sedimentary beds in the area of Sihetun Dakangpu belongs to the middle bed of Yixian formation. REE analysis implies that there are intimate relationships between the thin beds of tuffite, tuffaceous siltstone and calcareous shale and the lava of the same beds in Yixian Formation, and that there exist some differences between different beds of Yixian Formation. The REE pattern also indicates that different beds of Yixian Formation have similar material sources. |
| CHEN Shu-wang,ZHANG Li-dong,GUO Sheng-zhe,ZHANG Chang-jie,PENG Yan-dong,JIA Bin,XING De-he,DING Qiu-hong,ZHENG Yue-juan.2002.Geological Characteristics of the Volcano-Sedimentary Rocks of Yixian Formation in Sihetun-Dakangpu Area[J].Acta Geoscientica Sinica,23(3):217-222. |
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