关键词: 焦家式金矿成矿理论, 成矿规律, 热隆-伸展, 阶梯式, 中国胶东, 金矿

Abstract:

The Jiaojia-style gold deposit in Jiaodong Peninsula, the most important type of gold deposit in China, belongs to the structure-controlled hydrothermal gold deposit. It can be subdivided into the altered-rock type in the fracture zone, gold-bearing quartz vein type, stockwork quartz vein type along the fracture zone, quartz-sulphide vein type, interlayer type along the detachment belt, altered-conglomerate type and breccia type along the basin margin faults. These types of gold mineralization took place mainly in the Early Cretaceous period. The ore-forming materials were derived from an intensive crust-mantle interaction. The Early Precambrian and Mesozoic ore-hosting rocks were experienced generally phyllic, pyritization, silicification and potassic alteration. Gold bodies are characterized by pinch out, branches, composite, repetition, lateral extension, lateral tilting, echelon and imbrication. The uplifting of hot magma, fluid activities and extensional detachment resulted in the massive formation of gold deposits in Jiaodong Peninsula. The coeval-melted segregation magma and activated fluids derived from the Early Cretaceous crust-mantle interaction are important carriers of migration and enrichment of gold materials. The extensional detachment resulted from magma uplifting provided favorable ore-hosting spaces for the gold mineralization. Therefore, a thermal uplifting-extension-controlled metallogenic theory is proposed. The Jiaojia-style gold deposit was caused by the large-scale thinning of the lithosphere in the Early Cretaceous period in the Eastern China, being controlled by extensional tectonics. The ore-controlling faults have the ladder-style variation from steep to gentle dip angles. The gold deposits are emplaced and enriched at the gentle angle fault segments and the break part from steep to gentle dip angles, displaying a ladder-like distribution pattern.