鲁西地区鲁山片麻状高钾二长花岗岩的成因

Genesis of Lushan Granulating High-potassium Monzonitic Granite in Luxi Area

鲁西是华北克拉通早寒武纪变质基底的主要出露区之一。分布在鲁山、上五泉、蔡店—辛庄镇、黄庄镇—房家圈—上升科峪一带的主要是片麻状高钾二长花岗岩,以条带状侵入体的形式出露在混合岩中或者大范围的广布。岩石样品表现出高Si O_2、高K_2O、低Mg O以及稀土总量较高、(La/Yb)_N较大并伴随较弱Eu负异常的地球化学特征,同时亏损大离子亲石元素,暗示其是由英云闪长岩在中下地壳部分熔融形成。

The Western Shandong Province is one of the major exposure terranes of early Precambrian metamorphic basement of the North China Craton. The Neoarehean gneissic K-rich monzogranites distributes in Lushan, ShangWuquan Caidian, Xinzhuangzhen Huangzhuangzhen Fangjiaquan and Shangshengkeyu areas to exhibit magmatic intrusions. It is emplaced into the nfigmatites or mass distribution. The K-rich monzogranites am characterized by high SiO2, K20 and low MgO, high TREE and （La/Yb）N ,with weakly negative Eu anomalies. They also show depletion of Nb, Ta and Ti in the primitive mantle-nomlalized spidergrams, suggesting that they were derived from partial mehing of tonalites at the nfiddle-lower crust.