摘要:
广东东莞厚街黑头山黑云母二长花岗岩体锆石SHRIMP U-Pb测定其岩浆结晶年龄为151.6 Ma(晚侏罗世),属燕山期岩浆活动产物。岩石化学成分富SiO2(>70%),富K2O(>4%);相对贫Al2O3(12%~14.4%),贫Sr、Ba、Eu、Ti和P;稀土配分曲线呈海鸥型,具明显的负铕异常。多方法综合判断认为黑头山花岗岩具明显的A型花岗岩特征,属弱过铝质A1型花岗岩,应是燕山期岩石圈拉张减薄构造背景下所形成的侵入岩体。
Abstract:
Heitoushan biotite monzonitic granite in Houjie Town, Dongguan, Guangdong province is located in the west end of Dalingshan complex granites, zircon SHRIMP U-Pb age show that it formed at 151.6 Ma (Late Juras-sic), which belongs to product of Yanshanian magmatism. On the chemical composition of the rock, Heitoushan granite rich in SiO2 (>70wt%), K2O (>4wt%);relatively poor in Al2O3 (12~14.4 wt%), poor in Sr, Ba, Eu, Ti and P;rare earth distribution curve shows the seagulls type, with obvious negative Eu anomaly. Comprehensive dis-crimination method found that Heitoushan granite possess obvious characteristics of A-type granite, further can be divided into peraluminous A1-type granite. This paper argues that Heitoushan A-type granite formed in Yansha-nian period under the background of the structure of the lithosphere extensional thinning.
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