山东沂水龙泉站金矿床地球化学特征

Geochemical Characteristics and Its Origin of Longquanzhan Gold Deposit in Yishui of Shandong Province

沂水龙泉站金矿与成矿有关的主要地质体以新太古代泰山岩群与燕山期花岗岩金含量较高。对黄铁矿地球化学的研究资料表明:早期黄铁矿为金矿物的主载矿物。稀土元素分布特征反映了成矿流体由早期相对中偏高温(260~330℃)和还原的环境向晚期低温和氧化环境演变的趋势。对方解石、石英包裹体的研究表明:包裹体均一温度变化范围较宽,在107~550℃之间,可分为125~160℃,177~230℃和260~330℃3个温度峰值集中区,分别反映了以中温石英为代表的早期成矿阶段(260~330℃),以中低温石英和方解石为代表的中期成矿阶段(177~260℃)和以低温方解石为代表的晚期成矿阶段(125~160℃)。其冰点温度变化于-2^-8.6℃之间,盐度在3.39wt%~12.39wt%之间。

Gold content in Longquanzhan gold deposit and major geological bodies which has close realtion with ore - forming are high in Taishan group and Yanshan granites. As proved by the results of studying geochemistry of pyrite, pyrite in early period is main carrier mineral of gold minerals. As proved by rare earth information, ore - forming fluid in early period is formed in medium- high temperature （260 -330℃ ） and reducing environment, and has the evolution trend to low temperature in late period and oxidizing milieu. As proved by the study to calcite and quartz enclosure, varation scope of homogenization temperature of enclosure is very wide between 107 -550℃. It can be divided into 3 temperature peak concentration areas as 125 - 160℃, 177 -230℃ and 260 -330℃ . It reflects early ore- forming period （260 -330℃ ）which mediumlow temperature quartz is its representative, middle ore-forming period （177 -260℃ ）which medium- low temperature quartz and calcite are representatives, and late ore - forming period （ 125 - 160℃） which low temperature calcite is its representative. Freezing temperature varies between -2 - -8.6℃, and salinity is 3.39wt% - 12.39wt%.