东川式层控铜矿中非层状矿体的形成机制初议

A DISCUSSION ON THE METALLOGENIC MECHANISM OF NON-STRATIFORM ORE BODIES OF DONGCHUAN STRATABOUND COPPER DEPOSITS

Although stratiform ore bodies are the dominant form of the Dongchuan type stratabound copper deposits, the non-stratiform ores of higher grade still play an important role in mining production. Three types of metallogenic mechanisms are proposed in this paper ie. structural activities, metamorphism, and magmatism respectively, among which the first type, especially the fracturing structure, is by far the most predominant. Fracturing structures mainly cause the redistribution of copper within a local domain, to form fissure-filling veins or to enrich the nearby stratitorm ore bodies. No great quantity or long distance transportation of ore materials can be found during the ore formation of this type. This is also evidenced by the study of stable isotope compositions. Ore bodies related to the diapiric blocks occurring at Fengshan, Yimen area, belong to a special kind of non-stratiform ore. It was formed in the same way of the stratiform Shishan ores (sedimentation-reworking), but not a result of late-staged reformation of Shishan ores. Neither metamorpnism nor magmatism plays an important part to the formation of non-stratiform ore bodies.