| Structure metallogeny holds the view that mineralization mainly takes place inthe evolutionary phase of some special structure system in the long geological history.Wulonggou ore concentration areas, located in East Kunlun Middle Part of QinghaiProvince, are full-fledged in its Paleozoic-Mesozoic structure, magmatism and goldmineralization, but fail to conduct thorough and intensive research on the relationshipbetween its geological structure, magmatism and gold mineralization. Therefore, thisstudy takes gold mineralization and Metallogenic Prognosis as the core topic, does arefined and painstaking research on space and time distribution in geological structure,rock association, petrology, geochemistry and typical ore deposit, and drawsconclusions as follows:(1) Wulonggou is located in the Northeast wing of Golmud-Wulonggoumetamorphic core complex, whose extension and disjunction have formed the originaleastnorth-oriented ductile shear zone and formed a unique core concentrationstructure of metamorphic core complex with fold deformation, resulting in the goldmineralization in this area.(2) The motion sequence and mechanical properties evolution in ductile shearzone deformation in Wulonggou ore concentration areas have been established, that is,the left-lateral normal slip ductile shear zone in Early Indo-Sinian; a shift from theleft-lateral normal slip to the left-slip thrusting and to the right-lateral normal slip inLate Indo-Sinian to Yanshanian ductile-brittle deformation phases; a shift from theright-lateral normal slip to the left-slip thrusting and back to the right-lateral normalslip in the Late Yanshanian to Himalayan brittle deformation phases.(3) Brittle-ductile deformation and early metallogenic hydrothermal alteration inWulonggou ore concentration areas take place in Late Indo-Sinian to EarlyYanshanian (235～197Ma). Brittle deformation and late mineralization take place inLate Yanshanian to Himalayan (91.9~21.0Ma), whose Early-Middle phases (51~21Ma) play a significant role in the process of mineralization.(4) Influenced by the structure of metamorphic core complex and its evolution,gold mineralization in Wulonggou ore concentration areas takes place in the processof intracontinental orogenic brittle deformation after the formation of metamorphiccore complex. Its metallogenic environment is relatively closed brittle deformationzone with weak deoxidation atmosphere; metallogenic materials include crust-mantle mixtures characterized by deep sources, shell source metallogenic materials andmixtures of non-deep sources such as metamorphic water and natural water.(5) Multi ductile-brittle ore-bearing shear zones of compatible ore blending inWulonggou areas are formed in Late Triassic to Early Cretaceous. The goldore-bearing structure there takes shape in Late Cretaceous to Early Tertiary, while thefive elements of gold deposits like “source, collection, transportation, storage andshelter” are established in Late Indo-Sinian to Himalayan.(6) Metallogenic Prognosis shows great deposit potentials in Huanglonggou andShuizhadonggou, with a278-ton estimate of gold resources and a167-ton of Au, anddeep exploration concerned should be consequently intensified. |
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