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Journal : Journal of Geoscience, Engineering, Environment, and Technology

Characteristics of Chromite Deposits at North Kabaena District, Bombana Regency, Southeast Sulawesi Province, Indonesia Hasria; Masri; Suryawan Asfar; Arisona; Ali Okto; La Ode Restele; La Ode Ngkoimani; Rika Yustika
Journal of Geoscience, Engineering, Environment, and Technology Vol. 6 No. 2 (2021): JGEET Vol 06 No 02 : June (2021)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2021.6.2.6424

Abstract

The study area is located in North Kabaena District, Bombana Regency, Southeast Sulawesi. This paper is aimed to describe characacristics of chromite deposits. This study is conducted in three stages, three stages including desk study, field work and laboratory analysis. Desk study mainly covers literature reviews. Field work includes mapping of surface geology and sampling of representative rocks types. Laboratory analysis includes the petrologic observation of handspecimen samples, petrographic analysis of the thin section and ore microscopy for polished section. The results of petrographic analysis show that olivine minerals are generally replaced by minerals orthopyroxene and has been alterated by lizardite type serpentine veins with a fractured structure. The mineral olivine is also replaced by the mineral chrysotile as a secondary mineral with a fibrous structure. Based on ore microscopy analysis show that chromite has generally experienced a lateritification process and has been replaced by magnetite, hematite and geotite minerals. Chromite has experience process of weathering and alteration from its source rock caused by tectonics that occurred in the study area. The results shows that the characteristics of chromite deposits in North Kabaena District Chromite deposits has generally encountered in peridotite rock which have a grain size of 0.3-20 cm. Furthermore, chromite deposits in the study area are also encountered in podiform deposits, distributed locally and shows podiform to tubular shape with the dimensions of 30-60cm.
Serpentinization Study On Ultramafic Rock at Morombo Area, Lasolo Islands District, North Konawe Regency, Southeast Sulawesi, Indonesia Hasria; Febiyanti; Masri; Ali Okto; Erzam S. Hasan; La Hamimu; Sawaludin; La Ode Muhammad Iradat Salihin; Wahab
Journal of Geoscience, Engineering, Environment, and Technology Vol. 7 No. 1 (2022): JGEET Vol 07 No 01 : March (2022)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2022.7.1.6643

Abstract

The research is in Morombo area, North Konawe Regency, Southeast Sulawesi. The purpose of this study was to determine the characteristics of serpentinized ultramafic rock and serpentine paragenesis. Research was conducted using field observations and laboratory analysis consisting of petrographic and geochemical analysis in the form of X-Ray Fluorosence (XRF). Petrographic analysis was carried out to identify the mineral content and textures in the rock and to determine the percentage of serpentine mineral presence. Both of these rocks are petrographically dominated by primary minerals olivine and clinopyroxine and secondary minerals namely lizardite, chrysotile, antiorite and opaque minerals. The XRF analysis was to determine the elements of Ni, Fe, Co, MgO, SiO2, CaO, Al2O3 and P in ultramafic rocks. The results of petrographic analysis show that serpentinized ultramafic rocks in the study area consist of serpentinized dunite and serpentinized peridotite. The formation of clay minerals in rocks does not occur because of the low serpentinization process in the rock. The results of XRF analysis showed that all samples in the bedrock showed Ni content above 0.2%. This is caused by the enrichment of Ni which is interpreted as a result of the serpentinization process along with the formation of lizardite in the rock. The serpentinization sub-processes in the study area comprised by hydration, serpentine recrystallization, and deserpentinization. Serpentine paragenesis is formed from the mid-oceanic ridge ocean floor, the orogenic phase to weathering. Substitution of Mg by Ni in ultramafic rocks will produce Ni-Serpentin. It is estimated that in the research area lizardite and chrysotile lizardite and chrysotile are the causes of Ni enrichment in bedrocks. The serpentinization characteristics of ultramafic rocks in the study area show a low to moderate level of serpentinization.
Petrogenetic Study on Ultramafic Rocks from Waturapa and Surrounding Areas, South Konawe Regency, Southeast Sulawesi Province Hasria; Masri; Muhammad Arba Azzaman; Muhamad Jerniawan
Journal of Geoscience, Engineering, Environment, and Technology Vol. 8 No. 1 (2023): JGEET Vol 08 No 01 : March (2023)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2023.8.1.11035

Abstract

The petrogenesis study of ultramafic igneous rocks in the South Konawe Region has been carried out by several previous researchers, however, petrogenesis of ultramafic igneous rocks in the Waturapa Region has never been carried out in detail. This study aims to determine the characteristics and petrogenesis of ultramafic igneous rocks in the Waturapa area using petrographic and geochemical analysis using the XRF method. Petrographic analysis was carried out to determine the relative abundance percentage of primary minerals in the form of olivine, clinopyroxene, orthopyroxene, and opaque minerals as well as secondary serpentine minerals which were formed later. Meanwhile, XRF geochemical analysis is used to determine the major and minor oxide content in rocks. This geochemical data is used to determine ultramafic rock types, and magma series and to interpret the tectonic setting of the research location. The results showed that the ultramafic rocks in the study area consisted of olivine websterite and lherzolite, both of which have been serpentinized which is characterized by the presence of serpentine minerals such as lizardite and chrysotile. These serpentine minerals are present as replacement minerals and fracture-filling minerals. The geochemical characteristics of the analyzed rocks showed a SiO2 content of less than 45%, high MgO content, and low K2O, TiO2, Na2O3, and P2O5 compounds. The igneous rocks in the study area are classified as ultrabasic or ultramafic rocks (peridot gabbro). Ultramafic rocks in the study area belong to the tholeiitic magma series that formed in oceanic islands or oceanic intraplate margins.
Petrochemistry of Ultramafic Rock in Baula - Pomalaa Ophiolite Complex, Southeast Sulawesi, Indonesia Cendrajaya, Rio Irhan Mais; Juarsan, Laode Ihksan; Masri; Rubaiyn, Al; Syahrul; Neni; Ramadani, Suci; Hasria
Journal of Geoscience, Engineering, Environment, and Technology Vol. 9 No. 1 (2024): JGEET Vol 09 No 01 : March (2024)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2024.9.1.14491

Abstract

Baula and Pomalaa Ophiolitic Complexes are part of East Sulawesi Ophiolite (ESO). The ultramafic rocks in the Baula and Pomalaa Ophiolite Complex mainly is peridotite and consist of harzburgite, lherzolite and olivine websterite, mostly serpentinized. Chemical and petrological research has focused on minerals, such as olivine, pyroxene, and spinel. This study examines the tectonic setting and temperature of ultramafic rock formation. Twelve ultramafic rock samples were examined using geothermometers made of pyroxene, petrographic examination, and coexisting olivine and spinel analyses. SEM and petrographic analysis of pyroxene lamellae and mylonite-ultramylonite structures allowed for the measurement of the geothermometer of ultramafic rocks. Using SEM-EDS, the coexistence of olivine and spinel was analyzed to determine the type of ultramafic tectonic setting. In the coexistence of olivine and spinel, olivine and spinel oxide compounds as tectonic setting markers in the form of Fo and Cr# values. Ultramafic rocks have different temperature levels, based on pyroxene thermometer, and the first one starts at a high temperature of 1000-1200ºC. It is characterized by thin, elongated augite lamellae. Instead, large lamellae characterize augite at medium temperatures (800–1000ºC). Irregular, anhedral, and broader forms of enstatite lamellae are typical of low temperatures (500–800ºC). Different generations of exsolution lamellae indicate that magma cooling was gradual. The distribution of #Fo ranged from 0.87 to 0.92, and Cr# values ranged from 0.13-0.19. According to coexisting olivine and spinel analysis. On the Olivine-Spinel Mantle Array (OSMA), the Fo and Cr# plot indicates that the peridotites tectonic setting was from the ocean floor and the magmatism was from MORB (Mid Oceanic Ridge Basalt). The Al2O3 vs. TiO2 pattern in spinel lherzolite also similar with Ampana and Kabaena peridotites magmatism.
Assessing the Carbon Sequestration Potential of Ultramafic Rocks in the Kolaka Ophiolite Complex, Southheastern Sulawesi: A Petrographic, Geochemical, and Mineralogical Study Syahrul; La Ode Dzakir; Riska; Rio Irhan Mais Cendra jaya; Masri
Journal of Geoscience, Engineering, Environment, and Technology Vol. 10 No. 1 (2025): Article In Press JGEET Vol 10 No 01 : March (2025)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Climate change has prompted significant global interest in carbon sequestration technologies, particularly using geological formations. This study investigates the potential of ultramafic rocks from the Kolaka Ophiolite Complex in Southeast Sulawesi for carbon sequestration, focusing on the mineralogical, petrographic, and geochemical characteristics that enhance their reactivity with CO₂. The research involved petrographic and mineragraphic analyses of 15 peridotite samples, geochemical measurements via X-ray fluorescence (XRF), and mineral characterization using scanning electron microscopy (SEM). The results revealed that Kolaka's ultramafic rocks, particularly harzburgite and lherzolite, exhibit moderate to high serpentinization, which enhances their reactivity with CO₂. Key minerals such as olivine, pyroxene, and serpentine, rich in magnesium, calcium, and iron oxides, demonstrate significant potential for mineral carbonation. Secondary minerals like magnesite and brucite were identified as products of carbonation, reinforcing the rocks' ability to act as carbon sinks. The discussion highlights that serpentinized peridotites are more effective for carbon sequestration than unaltered ones due to increased mineral reactivity. The presence of magnesite and Cr-Fe-rich carbonates, alongside serpentine veins, indicates that fluid-rock interactions have promoted ongoing carbonation processes. The Kolaka ultramafic rocks, therefore, hold strong potential for long-term carbon storage, offering a promising solution for reducing atmospheric CO₂ levels