GOLD MINERALIZATION AT LATUPPA AREA LUWU REGENCY <BR />SOUTH SULAWESI PROVINCE

• Main Author: Najamuddin
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/5126
• Institution: Institut Teknologi Bandung

<b>Abstrak :</b><p align=\"justify\"> <br /> Gold mineralization, which is located in Latuppa area, Luwu Regency, South Sulawesi Province, belongs to the West Sulawesi Volcanic-Plutonic Arc and is situated between two main faults, i.e., Pa/u Koro and Saddang. The area is occupied by meta-sedimentary rocks of Latimojong Formation (Late Cretaceous) and andesitic lava flow of Lamas\' volcanic rocks (Paleocene-Oligocene). These rocks were intruded by biotite monzogranite (Late Miocene-Pliocene) and subvolcanic rocks (dacite and andesite). <br /> <br /> <br /> Mineralization, in general, is well developed within the biotite monzogranite and a small part within metasediment. Mafic monzogranite, dacite and andesite porphyry are assumed to be a source for mineralization. Mineralization is commonly in the forms of stockworks (veinlets), veins, banded and dissemination; locally, oreshoot and brecciation are also found. The presence of stockworks (veinlets) and dissemination characterize a porphyry type while vein and banded indicate an epithermal type. <br /> <br /> Hydrotermal alteration observed is potassic, propylitic, phyllic and argillic assemblages. Potassic and argiliic alteration possibly indicate porphyry and epithermal types respectively. <br /> <br /> Ore minerals of high temperature consisting of magnetite, pyrrhotite, arsenopyrite and bornite, are possibly indicative of a porphyry type. Ore minerals of low temperature, comprising cinnabar and stibnite, caharacterize the epithermal type. Ore minerals, which are commonly found, are pyrite, sphalerite, galena and chalcopyrite. Non-ore minerals are quartz, calcite, epidote and siderite white guthite and jacobsite are secondary minerals. General trends of mineralization are north-south, southwest-northeast; locally east-west. Analyitical results of gold within surface samples range from 0.02-70.8 ppm while core samples range from 0.02-41.2 ppm. <br /> <br /> Gold mineralization in Latuppa was derived from fluid mixing between high salinity fluids (> 6 wt % NaCl equivalent) (magmatic) and terminated with low salinity fluids (1,7 wt % NaCl equivalent) (meteoric) with homogenization temperatures range from 351-143°C. Combined mineralogical observation and fluid inclusion study, it is suggested that gold mineralization in Latuppa was formed by several hydrotermal episodes and belongs to epithermal-porphyry type of low suiphidation.