A Low-Sulfidation Epithermal Mineralization in the River Reef Zone, the Poboya Prospect, Central Sulawesi, Indonesia

Vein Textures, Ore Mineralogy, and Fluid Inclusions

Tomy Alvin Rivai, Kotaro Yonezu, Syafrizal, Kenzo Sanematsu, Damar Kusumanto, Akira Imai, Koichiro Watanabe

Research output: Contribution to journalArticle

Abstract

The Poboya Prospect lies along the North Northwest - South Southeast Palu-Koro Fault Zone in the central part of the West Sulawesi Arc. The geology of the area consists of the Palu Metamorphic Complex overlain by the Paleogene-Neogene Tinombo Formation of volcanosedimentary rocks, the Celebes Molasse sediment, and Late Cenozoic granitic rocks. Petrography, scanning electron microscope with energy-dispersive spectrometry (SEM-EDS), electron probe microanalyzer (EPMA), and fluid inclusion microthermometry were carried out to examine vein textures, ore mineralogy, and characteristics of the ore-forming fluid responsible for mineralization in the River Reef Zone, the Poboya Prospect. Textures of quartz-carbonate veins in the River Reef Zone include massive micro-comb, moss, colloform, crustiform, mosaic, feathery, flamboyant, lattice bladed, ghost bladed, parallel bladed, and saccharoidal textures representing primary growth, recrystallization, and replacement. The homogenization temperature and fluid salinity are 240–250°C and 0.3–0.7 wt% NaCl eq., respectively. Ore minerals precipitated in the early stage consist of electrum, naumannite-aguilarite, chalcopyrite, pyrite, marcasite, sphalerite, and pyrrhotite. Apart from pyrrhotite, these ore minerals were also precipitated in the late stage along with selenopolybasite, freibergite, argyrodite, pyrargyrite, and galena. Selenium more preferably occurs as the crystallographic replacement of sulfur in naumannite-aguilarite, argyrodite, pyrargyrite, selenopolybasite, and freibergite instead of as independent selenide minerals. The low-sulfidation epithermal deposit in the River Reef Zone, the Poboya Prospect, illustrates the potential of the West Sulawesi Arc, particularly along the Palu-Koro Fault Zone, to host epithermal gold mineralization.

Original languageEnglish
JournalResource Geology
DOIs
Publication statusPublished - Jan 1 2019

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Reefs
Mineralogy
fluid inclusion
Ores
mineralogy
reef
Textures
texture
Rivers
ore mineral
pyrrhotite
mineralization
Minerals
Fluids
fault zone
replacement
river
epithermal deposit
electron
marcasite

All Science Journal Classification (ASJC) codes

  • Geology
  • Geochemistry and Petrology

Cite this

@article{a06bc32b19cd407498d4f1835dbbe2c4,
title = "A Low-Sulfidation Epithermal Mineralization in the River Reef Zone, the Poboya Prospect, Central Sulawesi, Indonesia: Vein Textures, Ore Mineralogy, and Fluid Inclusions",
abstract = "The Poboya Prospect lies along the North Northwest - South Southeast Palu-Koro Fault Zone in the central part of the West Sulawesi Arc. The geology of the area consists of the Palu Metamorphic Complex overlain by the Paleogene-Neogene Tinombo Formation of volcanosedimentary rocks, the Celebes Molasse sediment, and Late Cenozoic granitic rocks. Petrography, scanning electron microscope with energy-dispersive spectrometry (SEM-EDS), electron probe microanalyzer (EPMA), and fluid inclusion microthermometry were carried out to examine vein textures, ore mineralogy, and characteristics of the ore-forming fluid responsible for mineralization in the River Reef Zone, the Poboya Prospect. Textures of quartz-carbonate veins in the River Reef Zone include massive micro-comb, moss, colloform, crustiform, mosaic, feathery, flamboyant, lattice bladed, ghost bladed, parallel bladed, and saccharoidal textures representing primary growth, recrystallization, and replacement. The homogenization temperature and fluid salinity are 240–250°C and 0.3–0.7 wt{\%} NaCl eq., respectively. Ore minerals precipitated in the early stage consist of electrum, naumannite-aguilarite, chalcopyrite, pyrite, marcasite, sphalerite, and pyrrhotite. Apart from pyrrhotite, these ore minerals were also precipitated in the late stage along with selenopolybasite, freibergite, argyrodite, pyrargyrite, and galena. Selenium more preferably occurs as the crystallographic replacement of sulfur in naumannite-aguilarite, argyrodite, pyrargyrite, selenopolybasite, and freibergite instead of as independent selenide minerals. The low-sulfidation epithermal deposit in the River Reef Zone, the Poboya Prospect, illustrates the potential of the West Sulawesi Arc, particularly along the Palu-Koro Fault Zone, to host epithermal gold mineralization.",
author = "Rivai, {Tomy Alvin} and Kotaro Yonezu and Syafrizal and Kenzo Sanematsu and Damar Kusumanto and Akira Imai and Koichiro Watanabe",
year = "2019",
month = "1",
day = "1",
doi = "10.1111/rge.12206",
language = "English",
journal = "Resource Geology",
issn = "1344-1698",
publisher = "Wiley-Blackwell",

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T1 - A Low-Sulfidation Epithermal Mineralization in the River Reef Zone, the Poboya Prospect, Central Sulawesi, Indonesia

T2 - Vein Textures, Ore Mineralogy, and Fluid Inclusions

AU - Rivai, Tomy Alvin

AU - Yonezu, Kotaro

AU - Syafrizal,

AU - Sanematsu, Kenzo

AU - Kusumanto, Damar

AU - Imai, Akira

AU - Watanabe, Koichiro

PY - 2019/1/1

Y1 - 2019/1/1

N2 - The Poboya Prospect lies along the North Northwest - South Southeast Palu-Koro Fault Zone in the central part of the West Sulawesi Arc. The geology of the area consists of the Palu Metamorphic Complex overlain by the Paleogene-Neogene Tinombo Formation of volcanosedimentary rocks, the Celebes Molasse sediment, and Late Cenozoic granitic rocks. Petrography, scanning electron microscope with energy-dispersive spectrometry (SEM-EDS), electron probe microanalyzer (EPMA), and fluid inclusion microthermometry were carried out to examine vein textures, ore mineralogy, and characteristics of the ore-forming fluid responsible for mineralization in the River Reef Zone, the Poboya Prospect. Textures of quartz-carbonate veins in the River Reef Zone include massive micro-comb, moss, colloform, crustiform, mosaic, feathery, flamboyant, lattice bladed, ghost bladed, parallel bladed, and saccharoidal textures representing primary growth, recrystallization, and replacement. The homogenization temperature and fluid salinity are 240–250°C and 0.3–0.7 wt% NaCl eq., respectively. Ore minerals precipitated in the early stage consist of electrum, naumannite-aguilarite, chalcopyrite, pyrite, marcasite, sphalerite, and pyrrhotite. Apart from pyrrhotite, these ore minerals were also precipitated in the late stage along with selenopolybasite, freibergite, argyrodite, pyrargyrite, and galena. Selenium more preferably occurs as the crystallographic replacement of sulfur in naumannite-aguilarite, argyrodite, pyrargyrite, selenopolybasite, and freibergite instead of as independent selenide minerals. The low-sulfidation epithermal deposit in the River Reef Zone, the Poboya Prospect, illustrates the potential of the West Sulawesi Arc, particularly along the Palu-Koro Fault Zone, to host epithermal gold mineralization.

AB - The Poboya Prospect lies along the North Northwest - South Southeast Palu-Koro Fault Zone in the central part of the West Sulawesi Arc. The geology of the area consists of the Palu Metamorphic Complex overlain by the Paleogene-Neogene Tinombo Formation of volcanosedimentary rocks, the Celebes Molasse sediment, and Late Cenozoic granitic rocks. Petrography, scanning electron microscope with energy-dispersive spectrometry (SEM-EDS), electron probe microanalyzer (EPMA), and fluid inclusion microthermometry were carried out to examine vein textures, ore mineralogy, and characteristics of the ore-forming fluid responsible for mineralization in the River Reef Zone, the Poboya Prospect. Textures of quartz-carbonate veins in the River Reef Zone include massive micro-comb, moss, colloform, crustiform, mosaic, feathery, flamboyant, lattice bladed, ghost bladed, parallel bladed, and saccharoidal textures representing primary growth, recrystallization, and replacement. The homogenization temperature and fluid salinity are 240–250°C and 0.3–0.7 wt% NaCl eq., respectively. Ore minerals precipitated in the early stage consist of electrum, naumannite-aguilarite, chalcopyrite, pyrite, marcasite, sphalerite, and pyrrhotite. Apart from pyrrhotite, these ore minerals were also precipitated in the late stage along with selenopolybasite, freibergite, argyrodite, pyrargyrite, and galena. Selenium more preferably occurs as the crystallographic replacement of sulfur in naumannite-aguilarite, argyrodite, pyrargyrite, selenopolybasite, and freibergite instead of as independent selenide minerals. The low-sulfidation epithermal deposit in the River Reef Zone, the Poboya Prospect, illustrates the potential of the West Sulawesi Arc, particularly along the Palu-Koro Fault Zone, to host epithermal gold mineralization.

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