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DC,a multi-metal ore field,is an important and well known producer of tin in China.Besides tin,also mined are zinc,lead,antimony,copper,arsenic,tungsten,mercury,silverand many other metals.Most of the deposits in this region occur in Devonian limestones andsiliceous shales.The ore deposits in this field are predominated by cassiterite sulphide type.As to theorigin of those deposits,they seem closely related to biotite granite.The ore-forming mate-rial is mainly derived from magmatic rocks,and part of it may come from the host rocks.The appearance of horizontal zoning of ore deposits in this field is extremely distinct,with LXG biotite granite as the core.Found in the magmatic rocks is molybdenum minera-lization.From the biotite granite outwards there displays such an occurring sequence as thefollowing:copper(zinc)skaru ore deposits,scheelite ore deposits,wolframite ore deposits,cassiterite sulphide ore deposits,lead-zinc(antimony)ore deposits and mercury or arsenic oredeposits.In this region the mineralizing-temperature zoning is also distinguishable,basicallyin agreement with the horizontal zoning of ore deposits.In other words,the formation tem-perature of ore deposits occurring around the granite is higher than that farther away fromthe granite.The following mineralization periods and stages can be divided:the first period,inclu-ding skarn sub-stage,cassiterite-quartz sub-stage,cassiterite-sulphide sub-stage,cassiterite-calcitesub-stage;the second period,including ferrosphalerite(galena)-franckeite sub-stage,jameso-nite-boulangerite sub-stage;and the third period,including pyrite-calcite sub-stage.The characters of material composition are as follows:ore minerals are characterized bygreat variety,perfect crystallinity,large grain-size and abundant sulfosalts.More than 90species of minerals have been identified.What is more interesting is that lead and antimonyin some of the cassiterite-sulfide deposits are derived from jamesonite rather than galena andstibnite,which provides an example rarely encountered in metallic deposits throughout theworld.
DC, a multi-metal ore field, is an important and well-known producer of tin in China.Besides tin, also mined are zinc, lead, antimony, copper, arsenic, tungsten, mercury, silverand many other metals. in this region occur in Devonian limestones andsiliceous shales.The ore deposits in this field are predominated by cassiterite sulphide type.As to theorigin of those deposits, they seem closely related to biotite granite.The ore-forming mate-rial is mainly derived from magmatic rocks, and part of it may come from the host rock. The appearance of horizontal zoning of ore deposits in this field is extremely distinct, with LXG biotite granite as the core. Found in the magmatic rocks is molybdenum minera-lization. From the biotite granite outwards there displays such an occurring sequence as the following: copper (zinc) skull ore deposits, scheelite ore deposits, wolframite ore deposits, cassiterite sulphide ore deposits, lead-zinc (antimony) ore deposits and mercury or arsenic oredeposits.In this region the mineralizing-temperature zoning is also distinguishable, basicallyin agreement with the horizontal zoning of ore depositss.In other words, the formation tem-perature of ore deposits happening around the granite is higher than that farther away fromthe granite.The following mineralization periods and Cassiterite-quartz sub-stage, cassiterite-sulphide sub-stage, cassiterite-calcitesub-stage; the second period, including ferrosphalerite (galena) -franckeite sub- stage, jameso-nite-boulangerite sub-stage; and the third period, including pyrite-calcite sub-stage. The characters of the material composition are: ore minerals are characterized by great variety, perfect crystallinity, large grain-size and abundant sulfosalts .More than 90species of minerals have been identified. What is more interesting is that lead and antimonyin some of the cassiterite-sulfide deposits are derived from jamesonite rather than galena andstibnite, wwhich provides an example rarely encountered in metallic deposits throughout the world.