LA-ICP-MS zircon U-Pb dating and petrochemical analysis were used to study the formation age, geochemical characteristics and diagenetic environment of Shangyingbei pluton and Maoershan pluton from southern Zhangguangcai Range.Shangyingbei pluton consists of mid-coarse-grained moyite and Maoershan pluton consists of mid-fine-grained biotite moyite.The weighted average age of the plutons are 178.9 ±2.7 Ma for Shangyingbei plu-ton and 183.7 ±2.4 Ma for Maoershan pluton, which define them both as Early Jurassic intrusive rock.Both plu-tons have higher content of SiO2 and K2O, and lower content of TiO2, MgO, CaO, and higher TFeO/MgO ratio.In Shangyingbei pluton the Aluminum index A/CNK＝0.98～1.08 and the Rittmann Index σ＝1.51～2.66, whereas in Maoershan pluton the A/CNK＝1.00 ～1.01, σ＝2.12 ～2.36.The rare earth element distribution model of Shangyingbei pluton is in seagull form, indicating an inconspicuous light-heavy REE fractionation, while Maoershan pluton has a rightwards REE element distribution model, and light REE is more enriched than heavy REE.Both plutons are enriched in Rb, K, and depleted in Ba, Nb, Ta, Sr, Ti, P, Ho, Er, U, Eu etc.Geochemical analysis indicates both plutons are A2-type post orogenic granite, emplaced in extensional environment of the post orogenic belt in the Xing-Meng orogenic belt.%通过LA-ICP-MS锆石U-Pb定年和岩石化学分析,研究了张广才岭南段上营北岩体和帽儿山岩体的形成年代,地球化学特征和形成环境.上营北岩体为中粗粒钾长花岗岩,帽儿山岩体为中细粒黑云母钾长花岗岩.上营北岩体的加权平均年龄为178.9 ±2.7 Ma,帽儿山岩体为183.7 ±2.4 Ma,均为早侏罗世侵入岩.上营北岩体和帽儿山岩体主量元素都具有SiO2和K2O含量较高, TiO2、 MgO、CaO含量较低, TFeO/MgO值较高的特点;上营北岩体A/CNK＝0.98～1.08,里特曼指数σ＝1.51～2.66;帽儿山岩体含铝指数A/CNK＝1.00～1.01,里特曼指数σ＝2.12～2.36.上营北岩体稀土元素配分模式为海鸥型,轻重稀土分馏不明显;帽儿山岩体稀土元素配分模式为右倾型,轻稀土较重稀土富集;两个岩体均富集Rb、 K, Ba、 Nb、 Ta、 Sr、 Ti、 P、 Ho、 Er、 U、 Eu等元素出现不同程度的亏损.地球化学特征分析显示上营北岩体和帽儿山岩体均为A2型花岗岩,为后造山型花岗岩,形成于兴蒙造山带后造山的伸展环境.
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