四川九龙柏香林铜矿床围岩稀土、微量元素地球化学

Minor Element and REE Geochemistry of the Baixianglin Cu Deposit in Jiulong,Sichuan

通过对柏香林铜矿床变沉积岩和变基性火山岩围岩稀土、微量元素分析显示,二云石英片岩稀土配分型为右倾型,具有较强的Eu负异常(Eu/Eu*=0.43~0.30,平均0.38),富集大离子亲石元素(Rb、Ba和U等),亏损高场强元素(Nb、Ta和Hf),与大陆地壳基本一致;黑云绿泥透闪岩的稀土、微量配分较为平坦,(La/Yb)N平均1.57,无明显Ce(Ce/Ce*平均0.88)与Eu异常(Eu/Eu*平均1.01)。综合分析认为,里伍岩群变沉积岩与变基性火山岩很可能形成于统一的弧后盆地构造背景,弧后盆地岩浆活动在其沉积过程中携带来丰富的金属元素,为江浪穹窿富铜矿床的发育奠定了物质条件。

This paper deals with minor element and REE Geochemistry of two-mica quartz schist and biotite-chlorite tremolitite as wall rock of the Baixianglin Cu deposit in Jiulong, Sichuan. Minor element and REE geochemistry of the two-mica quartz schist is characterized by enrichment in large ion lithophile element such as Rb, Ba and U as well as LREE, and depletion in high field-strength element such as Nb, Ta and Hf with 6Eu value of 0.3-0.43. Minor element and REE geochemistry of the biotite-chlorite tremolitite is characterized by （La/Yb）n of 1.57, mean δCe value of 0.88 and mean 8Eu value of 1.01. These indicate that wall rock of the Baixianglin Cu deposit was formed in a back arc basin where magmatic activity was responsible for ore material origin.