| 甘肃北山早古生代蛇绿岩带的特征及演化 |
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| 作者姓名： | 张扬 何国琦 |
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| 作者单位： | 同济大学，北京大学 |
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| 摘 要： | 板块构造学说问世以来,地质学有了突破性进展。现代大洋岩石与大陆蛇绿岩之间明显的相似性,使人们把蛇绿岩视为消失大洋在大陆造山带中的残留标志。笔者综合有关蛇绿岩的研究成果,在我国北山首次确定了早古生代的蛇绿岩带,并对其发展演化做了研究
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| 关 键 词： | 蛇绿岩带 残余洋壳 岩石化学图解 |
THE CHARACTERISTIC AND EVOLUTION OF EARLY PALEOZOIC OPHIOLITE IN BEISHAN AREA,GANSU |
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| Authors: | Zhang Yang |
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| Institution: | Zhang Yang (Department of Geotcchnical Engineering Tongji University)
He Guoqi (Department of Geology Beijing University) |
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| Abstract: | Xichangiing ophiolite belt is preserved well and is recognized first in Beishan area.The- re are three rock units in Xichangjing ophiolite.The lower unit is composed of peridotite and ilerzolite.In the middle unit,the cumulated troctolite and layered gabbro are pres- ent.The upper unit is characterized by sheeted dykes,pillow lavas and oceanic basalt, which had undergone metamorphism.Above the ultramafite and mafite,there are many fragments of oceanic sediment rock. The petro-chemical study indicates that the three rock units have the same magma chamber and are products oi magmatic differentiation.Also,it is suggested that the for- marion of Xichangjing ophiolite differs from the type of MORB,and may be explained by themodel of small oceanic crust,which has developed on continental basement and closed at the end of Ordovician. |
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| Keywords: | ophiolite belt residual ocean crust geochemical graph |
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