- 著者
-
吉江 隆
大坪 徹
奥 直樹
上田 祐子
- 出版者
- 資源地質学会
- 雑誌
- 資源地質 (ISSN:09182454)
- 巻号頁・発行日
- vol.65, no.2, pp.53-79, 2015
Pan Pacific Copper Co.,Ltd. (PPC) commenced intensive explorations for the Caserones copper-molybdenum deposit and its cluster deposits in 2006 just after the acquisition of property and confirmed more than one billion tons of resources in 2009. <br>Vertical mineral zonation related to weathering is distinctive in the Caserones deposit, which the oxidized and sulfide supergene enrichment zones are determined over the primary mineralization. <br>Primary Cu-Mo sulfide mineralization follows both spatially and temporally the intrusion of dacite porphyry (PDA), a NNW-SSE elongated dyke intruding into the Paleozoic monzogranite batholith and the breccia probably in close genetic relationship with PDA. Three stages of the mineralization are recognized. Early stage accompanies potassic alteration. Veins equivalent to EB and A in El Salvador occur in this stage. Quartz-sericite alteration is the most prominent alteration and dominated in the third stage which is also the most intensive period of veining of the so-called D-vein. The porphyry mineralization is overlapped by an epithermal-like mineralization (ZEP) which carries pyrite, chalcopyrite, galena and tennantite. Fluid inclusion study recognizes two types of inclusions, type Ⅰ(V+L+S) and type III(V+L, V<30%). Type Ⅰ inclusions show homogenization temperature ranging 283-463°C and salinity between 31.8-44.4% NaCl eq. On the other hand, type III inclusions have temperature ranging 329-474°C and salinity ranging 4.6-20.6% NaCl eq. Fluid inclusions of ZEP are characteristically low both in temperature and salinity, 200-288°C and 2.9-7.4% NaCl eq respectively. Chronological study indicates 17-19 Ma for dacite porphyry, sericite and molybdenite.<br>Several prospects are known in the project area and they show common characteristics in geology with the Caserones deposit, while interpreted period of those magmatism and mineralization is possibly older than of the Caserones. Exploration for those deposits are still in reconnaissance stage, but some 100-200 million tons of sulfide potential is estimated for Cerro Sur prospect and some 40 million tons of oxide potential is expected for Angelica prospect.