再论兴隆沟组火山岩成因

Re-discussion on the origin of volcanic rocks of the Xinglonggou Formation,North China.

本文通过对辽西北票地区兴隆沟组安山质火山岩的组分和岩相学研究,发现作为捕虏晶的斜方辉石存在反环带和韵律环带。根据具反环带结构的斜方辉石的微量元素丰度研究,提出兴隆沟组火山岩是岩浆混合作用的产物而非下地壳拆沉作用的产物。对比华北克拉通北缘不同时代,不同成因的单斜辉石,推测辉石有可能来源于早中生代下地壳的堆晶岩。

Based on the composition and petrographic studies of the andesitic volcanic rocks of the Xinglonggou Formation in Beipiao region, western Liaoning Province, we found revisely-zoned and rhythmically-zoned orthopyroxenes as xenocrysts. The trace element abundances and patterns of the revisedly-zoned orthopyroxene xenocrysts indicate that the volcanic rocks of the Xinglonggou Formation wer the products of magma mixing rather than the lower-ernst delamination. These orthopyroxenes perhaps came from the Early Mesozoic Lower crust cumulates according to the comparison to clinopyroxenes of different ages and origins from the north margin of North China Craton.