#TITLE_ALTERNATIVE#

• Main Author: AZRI (NIM : 12009032) ; (Pembimbing : Prof. Dr. Emmy Suparka ; Ir. Nurcahyo I. B., MT, Ph.D), AMALINA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17907
• Institution: Institut Teknologi Bandung

Research area is administratively located in Erstberg District - Tembagapura, Mimika Regency, Papua Province and geographically, located in coordinate 736600 E – 738200 E and 9548500 N – 9549300 N. This study uses core data from nine wells, those are TEW03-28, TE03-25, TE05-15, TE07-13, TE07-14, TE09-08, TE16-03, DMLZ05-05, and DMLZC07-01. Macroscopic observation along with microscopic analysis such as petrography analysis, mineragraphic analysis, NIR analysis, and also geochemical assay analysis were made on each core samples to determine the zonation of alteration and with mineralization. Based on these analyzes, showed that the study area is composed of three rock units, from old to young, namely: Limestone-Shale Unit, Dolomitic Limestone Unit, and Diorite Intrusion Unit. In the study area, there are eight alteration zones. Those are (1) Dolomite-Calcite-Pyrite Zone, (2) Diopsid-Forsterite-Muscovite Zone, (3) Biotite-Feldspar-Quartz Zone, (4) Garnet-Biotite-Diopsid-Magnetite Zone, (5) Magnetite-Anhydrite Zone, (6) Tremolit-Actinolite-Talc-Anhydrite Zone, (7) Sericite-Calcite-Quartz Zone, and (8) Anhydrite-Sericite Zone. Mineralization processes that occur in the study area includes two types, porphyry skarn and supergene enrichment. The mineralization process formed three zones, namely: Pyrite-Chalcopyrite-Pyrrhotite Zone, Chalcopyrite-Bornit-Magnetite Zone, Bornite-Covellite-Digenit Zone. The age of rocks in the study area is estimated Late Cretaceous-Paleocene from calcareous sedimentary rocks, then intruded by Pliocene Intrusion, resulting the formation of Zone (1) by metamorphism process as the early stage in skarn mineralization. Calcsilicate hydrothermal fluids which came then, after the outer edge monzodiorit frozen, entered through cracks that formed by Ertzberg Fault 1 Zones and overprinting Zone (1), and forming the zonation due to multiple stage metasomatism. This early retrograde stage formed Zone (2), Zone (3), Zone (4), and Zone (5). Hydrothermal fluid has been mixed with meteoric fluid, resulting lower acidity and temperature and formed Zone (6) and Zone (7). Degradation in solubility of the fluids causing the final retrogade stage and precipitated Zone (8) in some places.