中文摘要：

蛇绿混杂堆积带地处鄂尔多斯地块与阿拉善地块的结合部位,也是早前寒武近东西向-北东向构造域与北北东向狼山构造带的交汇部位。该混杂岩由蛇绿岩岩块和混杂基质组成。蛇绿岩块有辉橄岩、辉石岩、辉长岩、斜长岩、玄武岩及硅质岩等,基质主要是橄榄岩。野外调查及室内鉴定结果显示,蛇绿岩岩块和基质遭受了较强的变质变形,地球化学研究表明其具有大洋壳蛇绿岩的特征。上述研究表明华北地块与阿拉善地块之间在早古生代曾经历了拉张-局限洋盆—最终碰撞闭会的全过程。

英文摘要：

The Jilantai ophiolitic melange belt is located in the intersection part of the Precambrian EW-NE-trending tec- tonic domain and NNE-trending Langshan structure belt in the conjunction of the Ordos and Alxa blocks. The melange con- sists of the ophiolite and hybrid matrix. Ophiolite ic composed of pyroxene peridotite, pyroxenite, gabbro, anorthosite, ba- salt and chert, etc. Matrix is mainly composed of peridotite. Field and laboratory investigations showed that its ophiolite and matrix were strongly metamorphosed and deformed. Geochemical studies show that the ophiolite has features of oceanic ophiolite. It is believed that the conjunction between the North China block and the Alxa block could have been experi- enced the whole evolution process from the extension, Limited oceanic basin, to final collision closure in the Early Paleo- zoic.