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研究区位于华北克拉通北缘东段,排山楼二长花岗岩体为一个小型的岩株,出露于排山楼韧性剪切带型金矿床的北部。岩石为不等粒似斑状花岗结构,主要由钾长石、更长石、石英、黑云母和少量角闪石构成,含有锆石、榍石、磷灰石、钛铁矿等副矿物,属于高钾钙碱性准铝质I型花岗岩。该二长花岗岩具有富钠,高Sr、Ba含量,重稀土强烈亏损和轻微的正铕异常等特殊的地球化学特征,从而推断其岩浆可能起源于加厚陆壳底部角闪岩类的部分熔融。锆石U-Pb年龄(128±1.3Ma)表明该岩体在燕山晚期白垩纪侵位。由于在排山楼矿床观察到二长花岗岩的侵位晚于控矿糜棱岩带、但岩体本身又发育了金矿化,根据本岩体与含矿韧性剪切带的密切时空关系,参照区域构造热事件与成矿作用的密切联系,认为排山楼二长花岗岩浆的侵位与控矿韧性剪切作用,可能是本区燕山晚期岩石圈伸展体系下同一构造热事件的不同侧面,因而二者应存在构造机制上的密切联系。但不排除控矿韧性断裂长期活动的可能性以及曾经有更早期次金矿化发生的可能性。
The study area is located in the eastern part of the northern margin of the North China Craton. The Paleishang granite is a small type of rock that is exposed to the northern part of the Paoshishan ductile shear zone gold deposit. The rocks are unequal granuliform-like granodioritic structures and are mainly composed of potash feldspar, longer feldspar, quartz, biotite and a small amount of amphiboles, which contain accessory minerals such as zircon, limestone, apatite and ilmenite, Belongs to high-K calc-alkaline quasi-aluminum type I granite. The monzonitic granites have special geochemical features such as high Na, high Sr, Ba, heavy heavy rare earth loss and slight positive Europium anomaly, so that the magma may originate from the partial melting of the amphibolites at the bottom of thickening continental crust . The zircon U-Pb age (128 ± 1.3Ma) indicates that this rock emplaced in the late Yanshanian Cretaceous. Due to the observation that the emplacement of the monzonitic granite in the Paishanlou deposit is later than that of the ore-controlling mylonite, the rock mass itself developed gold mineralization. According to the close spatio-temporal relationship between this rock mass and the ore-bearing ductile shear zone, According to the close relationship between tectonic events and mineralization, it is considered that the emplacement and ore-controlling ductile shearing of the Paleozoic magma in the Paleishan Block may be caused by the different tectono-thermal events under the Late Yanshanian lithosphere extension system , So the two should exist in the structural mechanism of the close contact. But does not rule out the possibility of long-term activities of the controlled ore toughness fracture and the possibility of earlier gold mineralization.