胶北隆起中生代壳幔岩浆的混合反应是巨量金质来源的关键

The mixing of Mesozoic crust-mantle magma is the key to the source of large amounts of gold deposits in the Jiaobei uplift, China

胶东地区金矿巨量金质来源一直是学界争论的焦点,很难找到有说服力的直接证据。在没有其它更有效的直接证明巨量金质来源的情况下,本文通过胶北隆起主要地质体新鲜岩石大量微量元素地球化学数据的变化规律,间接得出中生代壳幔岩浆的混合反应是巨量金质来源的关键,即郭家岭和伟德山两期壳幔岩浆的混合反应和演化可能是巨量金质来源的主要形成机制,同时更是热量供给源,而玲珑花岗岩可能是少量金质的提供者和主要赋矿地质体。胶东地区金矿主要成矿时间(130~105Ma)与郭家岭(130~125Ma)和伟德山(126~108Ma)两期花岗岩浆演化结晶时间完全吻合,说明其关系密切,岩浆混合反应和冷凝期,岩浆热液上升运移沉淀成矿。该区中生代地质体对早前寒武纪的地球化学环境有一定的继承性,中生代地壳混合了大量地幔物质,Au丰度偏高,平均为1.31×10;,为地球化学高背景场。

The huge material source of gold deposits in Jiaodong area has always been the focus of academic debate, and it is difficult to find convincing evidence. In the absence of other more effective direct proof of the source of huge gold, this paper indirectly draws the conclusion that the huge gold comes from the mixing reaction of Mesozoic crust-mantle magmas based on the variation law of large amounts of trace elements geochemical data from fresh rocks of main geological bodies in Jiaobei area. The mixing reaction and evolution of the Guojialing and Weideshan crust-mantle magmatism may be the main mechanism for the formation of huge gold source, and it is also the source of heat supply. Linglong granite may be a small amount of gold supplier and the main ore-hosting geological body. The main metallogenic time of gold deposits in Jiaodong area(130~105 Ma) is the same as the evolution and crystallization time of granite magma of Guojialing(130~125 Ma) and Weideshan(126~108 Ma) granites, which means they are closely related. During magma mixing reaction and condensation period, magmatic hydrothermal fluids ascending, migration, and precipitation mineralization. The Mesozoic geological bodies inherited geochemical environment of Early Precambrian in this area. The Mesozoic crust was mixed with a large amount of mantle materials, and the Au abundance was high, averaging 1.31×10;, which was a geochemical high background.