贵州东部镇远金堡铅锌矿床地球化学特征研究

Geochemical Characters of Jinbao Lead-zinc Deposit in Zhenyuan of Eastern Guizhou

对贵州黔东镇远金堡铅锌矿床碳—氧、硫同位素及流体包裹体温度、盐度地球化学特征研究,方解石和白云石碳同位素在-5.7‰-6.9‰,落在典型的火成碳酸岩区域(-5‰-7‰);氧同位素在11.2‰12.2‰之间,略高于火成碳酸岩。闪锌矿硫同位素分布集中,在11.5‰14.2‰之间,结合该区域的碳同位素,暗示成矿物质来自于深部地幔或岩浆作用。流体包裹体均一温度在106 238℃之间,冰点温度在-1.8-24℃之间,对应的盐度为2.926.1 wt%NaCl eq.,判断该矿床成矿流体属中低温、中高盐度的成矿流体。从闪锌矿流体包裹体均一温度-盐度变化趋势分析,成矿温度及盐度范围变化较大,成矿流体经历了不混溶过程,可能是岩浆热液在降温减压的过程中发生不混溶现象而形成的。结合区域地质条件及矿床地质特征分析研究,认为镇远金堡铅锌矿床成矿热液来源及其可能与岩浆热液有关。

Inthispaper,itdidgeochemicalcharacterstudyforC-O2,sulfurisotopeandflowinclusion temperature on Jinbao lead-zinc deposit in Zhenyuan,the C isotope of calcite and dolomite is -5.7‰ to -6.9‰,the O isotope in the typical igneous carbonate rock area is 11.2‰ to 12.2‰ and higher than igneous carbonate rock.Sulfur isotope in sphalerite is 11.5‰to 14.2‰and distributes intensively.With the C isotope, it’s inferred the metallogenic material comes from deep mantle and magmatism.The flow inclusion temperature is 106＆#176;to 238＆#176;,the freezing point is -1.8＆#176;to 24＆#176;and the salinity is 2.9 to 26.1wt%NaCleq.It can be judged the metallogenic flow of this deposit has low-middle temperature and middle-high salinity.By analysis the changing tendency of temperature and salinity,the metallogenic humidity and salinity changes a lot,the flow experienced unmixing process,it maybe caused by the unmixing phenomena when the magmatic hytrothermal decrease the temperature and pressure.By study the regional geologic condition and deposit geologic feature, it’s thought the metallogenic flow source of Jinbao lead-zinc deposit perhaps has relation with magmatic hy-drothermal.