| 辽东半岛早元古宙地壳的演化 |
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| 引用本文： | 张秋生.辽东半岛早元古宙地壳的演化[J].地球学报,1987,9(2):155-163. |
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| 作者姓名： | 张秋生 |
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| 作者单位： | 长春地质学院 |
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| 摘 要： | 辽东半岛早元古代岩层可以划分为三个演化阶段。早期阶段,在硅铝壳内的滑动面上裂开而造成宽度远较现存早元古代岩层分布为宽的裂谷式地槽,最突出的特点是构成了优冒地槽同时异相并存的局面。中期阶段层状的堆积物是由大石桥岩组与盖县岩组所构成,前者为厚约4km的厚层状碳酸盐岩,后者为厚度大于5km的泥砂质岩石。晚期阶段、局限于南部局部地区,由石英砂岩、石英岩、长石石英砂岩组成,厚度大于10km。由同位素年龄资料所知,早元古宙地槽下限为2300—2500Ma,上限可能为1700Ma,2000Ma前后发生过一次中等程度地质
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EARLY PROTEROZOIC CRUSTAL EVOLUTION OF THE EAST LIAONING PENINSULA |
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| ZHANG Qiu-sheng.EARLY PROTEROZOIC CRUSTAL EVOLUTION OF THE EAST LIAONING PENINSULA[J].Acta Geoscientia Sinica,1987,9(2):155-163. |
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| Authors: | ZHANG Qiu-sheng |
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| Institution: | Changchun College of Geology |
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| Abstract: | The evolution of the Early Proterozoic strata in the East Liaoning Peninsula is divided into early, middle and late stages. During the early stage, the strata were split on the sliding plane in the sial, leaving behind a rift geosyncline that was much wider than the existing Early Proterozoic sequence and characterized by contemporaneous heteropic facies. In the middle-stage evolution, the stratified accumulations were made up of Dashiqiao and Gaixian formations. The former consists of dominant thick-bedded carbonate rocks of four km thick, while the latter is composed of clayey and sandy rocks of five km thick. The late-stage evolution was limited within some locations in the southern part of the Peninsula, where quartz sandstone, quartz-ite and feldspathic quartz sandstone predominate with a thickness of more than 10 km. According to the isotopic age determination, the lower limit of the Early Proterozoic geosyncline ranges from 2,300 to 2,500 Ma., and the upper limit is probably around l,700Ma. At about 2,000 Ma. before present occurred a mediumscale geological event. The crustal evolution in the area is featured by the Archaean complex as bed rocks, and the Early Proterozoic geosyncline of tensile nature in the early stage, being intensely compressed during the middle stage and uplifted in the northern part in the late stage, with the emplacement of granite-gabbro series and local piedmont deposits formed in the southern part. The geosynclines of different patterns control individual ore deposits and ore associations. |
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