STRATA-BOUND ORE DEPOSITS OF DEVONIAN IN NANLING AREA, SOUTH CHINA

The Nanling of South China is one of the most important areas of nonferrous metal mineral resources. Based on incomplete statistical figures, strata-bound lead-zinc, pyrite, tungsten,tin, mercury, antimony and barite ore deposits have been found in Devonian of this area. There are ten's medium to large scale deposits ezplorated and numbers of small deposits spread far and wide. According to genetic types, these deposits can be classified into diagenetic, diagenetic-epigenetic, volcanic exhalation-sedimentary, superimposed and mixed hydrothrmal ore deposits. Four metallogentic models have been established: 1. submarine vadose circulating volcanic exhalation-deposition; 2. basinal diagenetic compactive fluids; 3. basinal thermal brine; 4. mixed hydrothermal metallogenic model. Although these strata-bound deposits are different in types and genesis, many similarities in their ore-controlling factors and distributon may be found. The main controlling factors are stratigraphy (formation), lithofacies and tectonic setting. Thereby, it is considered that any geologic factor controlling the ore formation could not be treated in isolation. The formation of any large scale ore deposit should be considered as the result of the coaction of various geological factors in certain geological settings, and those factors affect and interact commonly each other. The stratigraphic horizon, lithofacies and tectonic setting are thought as main factors for controlling the diagenetic-epigenetic strata-bound ore deposits, and three factors are concordant spatially. When the formation of ttrata-bound ore deposits are related to magmatism, the regional large fault, lithofacies zone, magmatic activity and metallogenesis often show the consistency. That is, the fault controlled early the lithofacies (or volcanic activity), and subsequently controlled the emplacement of magmatic rocks and the migration, circulation and final enrichment of the metallogenetic solutions.