辽宁庄河鞍子山超单元岩浆就位机制

    MAGMA EMPLACEMENT MECHANISM OF THE ANZISHAN SUPER UNIT IN THE EAST PART OF ZHUANGHE, LIAONING

    • 摘要: 鞍子山超单元由4个单元组成,各单元中的叶理极发育,闪长质包体强烈压扁,钾长石斑晶定向排列,以上三者均平行于剪切带分布。由早期到晚期具有叶理构造减弱,包体数量减少,压扁程度降低,斑晶定向逐渐消失的变化趋势。包体应变指数K值为0<K<1,属于压扁型椭球体。根据包体旋转指向和定向薄片资料分析,鞍子山超单元主要受北东向吴炉—郑家山—上腰岭左旋剪切带的控制,属于楔形侵入膨胀式就位机制的产物。

       

      Abstract: The Anzishan super unit in Zhuanghe, Liaoning, consists of four units. They are characterized by well developed foliation, strongly flattened dioritic inclusions and oriented K feldspar phenocrysts, the three of which are all parallel to the shear zone. From the early to late stages the units had the following trends of change: foliation weakened, inclusions were reduced and their degree of flattening lowered and the preferred orientation of the phenocrysts disappeared gradually. The Flinn index K obtained by the strain measurement of the inclusions is 0<K<1; so the inclusions belong to flattened ellipsoids. On the basis of the direction of rotation of inclusions and data of oriented thin sections, the authors hold that the Anzishan super unit is mainly controlled by the NE trending Wulu Zhengjiashan Shangyaoling sinistral shear zone and that its magma emplacement mechanism is of wedge shaped intrusion expansion type.

       

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