Fluid Inclusion Study of Epithermal Quartz Veins from the Kyaukmyet Prospect, Monywa Copper-Gold Ore Field, Central Myanmar

The Kyaukmyet prospect is located near the main ore bodies of the Kyisintaung and Sabetaung high-sulfidation Cu-Au deposits, Monywa copper-gold ore field, central Myanmar. Lithologic units in the research area are of mainly rhyolite lava, lapilli tuff and silicified sandstone, mudstone and siltstone units of Magyigon Formation which hosted to be polymetallic mineralization. Our field study recorded that epithermal quartz veins are hosted largely in rhyolite lava and lapilli tuff units. Those quartz veins show crustiform, banded (colloform), lattice bladed texture and comb quartz. The main objectives of the present research in which fluid inclusion studies were considered to conduct the nature, characteristics and hydrothermal fluids evolution from the epithermal quartz veins. In this research, there are three main types of fluid inclusions are classified according to their phase relationship (1) two-phase liquid-rich inclusions, (2) the coexisting liquid-rich and vapor-rich inclusions, and (3) only vapor-rich inclusions. Microthermometric measurements of fluid inclusions yielded homogenization temperatures (Th) of 148–282 °C and final ice-melting temperature (Tm)  of -0.2°C to -1.4°C . The value of (Tm) are equal to the salinities reaching up 0.35 to 2.07 wt % NaCl equiv. respectively. Estimation formation temperature of the quartz veins provide 190°C and 210°C and paleo-depth of formation are estimated to be between 130m and 210m. Petrography of fluid inclusion and microthermometric data suggest that fluid boiling as well as mixing processes were likely to be happened during the hydrothermal fluid evolution at the Kyaukmyet prospect. According to the characteristics of many parameters including petrography of fluid inclusion, microthermometric data, paleo-depth, evidence of quartz vein textures and types of hydrothermal alteration from the Kyaukmyet prospect allows to interpret these data to be the low-sulfidation epithermal system

MINERAL POTENTIAL MAPPING USING GEOGRAPHIC INFORMATION SYSTEMS (GIS) FOR GOLD MINERALIZATION IN WEST JAVA, INDONESIA

Western Java is a part of the Sunda Banda magmatic belt. This belt is well known to be host for several gold deposits in Indonesia, the distribution of 107 Au occurrences in this area was examined in terms of spatial association with various geological phenomena. The goal of this project is to use GIS to conduct weights of evidence (WofE) model for gold mineralization in West Java, Indonesia. A Geographic Information System (GIS) is a computer system for capturing, storing, querying, analyzing, and displaying geospatial data and weight of evidence method is one of the most important datadriven methods for mapping in GIS. The method is a probability based on technique for mapping mineral potential using the spatial distribution of known mineral occurrences. Therefore this method is very useful for gold potential mapping. There are six evidences maps such as NE–SW lineaments NW–SE Lineament, host rocks, heat sources, clay alteration and limonitic alteration, have been combined using a weights of evidence model to predict gold potential in West Java. The best predictive map generated by this method defines 21.62% (9902 km) of study area as favourable zones for gold mineralization further exploration work. It predicts correctly 74 (92.5%) of the 80 model deposits and predicts correctly 26 (96.35%) of the 27 validation deposits, has 6 main 2 prospective target for future exploration are located in Bayah Dome, southern mountain, Honjie Igneous Complex and Bogor zone, Purwakarta. Bayah Dome is highest potential area for gold deposit like Gunung Pongor, Cikidang, Cirotan, Ciawitali, Cikotok destricts and other deposits. The potential area of Au occurrences in research area is associated with NE–SW and NW–SE structure/ lineaments, dominated surrounding the Tertiary intrusive rock unit and hosted in Miocene to Pleistocene lithology rock unit

Study on Epithermal Gold Mineralization System at Shwebontha Prospect, Monywa Copper-Gold Ore Field, Central Myanmar

The Shwebontha prospect area is situated in the Central Volcanic Belt, central Myanmar, where the well-known Sagaing Fault serves as its eastern boundary. This study aims to document key the mineralogy, host rock geochemistry and ore mineralizing fluids. The mineralization, hosted by Upper Oligocene to Middle Miocene rhyolites, displays a strong lithological control. Mineralization is characterized by gold-bearing silicified massive ore and chalcedonic quartz veins in which sulfides are clustered and disseminated not only in quartz gangue but also in rhyolite host rocks. The significant ore minerals in the mineralized veins include pyrite, sphalerite, galena, chalcopyrite, and gold. Common hydrothermal alterations such as silicic, argillic and propylitic alteration types are recognized. According to the fluid inclusion data and interpretation, ore mineralizing fluids in the research area are characterized by formation temperatures of 260-280 °C and salinity of 0.35-2.41 % wt. NaCl eq. respectively. Mixing of hydrothermal fluids was generally considered to be an effective mechanism for ore transport and deposition

MINERALOGY, GEOCHEMISTRY, AND SEQUENTIAL EXTRACTION EXPERIMENT OF REE IN WEATHERED ANGGI GRANITE, MANOKWARI REGENCY, WEST PAPUA, INDONESIA

This research objective is to identify geochemical andmineralogical characteristics of Rare earth elements(REE) in the weathering products of Anggi Granite, which is located in Manokwari Regency, WestPapua, Indonesia. The research is conducted on 7samples of fresh rocks and 7 samples of weatheredrocks of Anggi Granite. The research analysis consists of petrography, XRD, XRF, and sequential extraction experiment, supported by secondary dataand references. Anggi Granite is S-type and peraluminous granite that contains zircon, monazite andapatite as a rare earth bearing minerals. Weathering products of Anggi Granite do not have a significant enrichment of REE, even some of the samplesare depleted in REE. REE in weathered Anggi Granite are dominantly present in the primary minerals,mostly in zircon and monazite. Extractable formof geochemical fractions include crystalline Fe-oxideoccluded fraction (ilmenite, hematite and goethite),and ion-exchangeable (illite, kaolin and chlorite).Enrichment of REE in the weathered Anggi Granite is influenced by the presence of resistant REEbearing minerals, in the forms of zircon and monazite, degree of weathering related to the presenceof secondary minerals, and other factors such as pHand E

Petrographic Characteristics and Geochemistry of Volcanic Rocks in the Kyaukmyet Prospect, Monywa District, Central Myanmar

The Kyaukmyet prospect lies approximately 5 km ENE of the highsulfidation Kyisintaung copper-gold deposit, Monywa district, central Myanmar. Geologically, the research area is remarked by magmatic extrusion that occurred during the Late Oligocene to Middle Miocene of Magyigon Formation which led to the outcrops of volcanic rocks. Study detailed on petrographical and geochemical of the Kyaukmyet volcanic rocks has not been performed before the present work. The principal aim of this paper is to document the petrographical and geochemical characteristics of volcanic suite rocks exposed in the Kyaukmyet prospect. The results of this data have provided insight into the origin of the rocks and petrogenetic processes during evolution. Petrographically, all the studied volcanic rocks in the research area show that trachytic and porphyritic textures with phenocrysts of quartz, plagioclase, and K-feldspar which are embedded in a fine to medium grained groundmass. The accessory minerals of this rock consist of biotite, chlorite and opaque mineral.Geochemically, these volcanic rocks having calc-alkaline nature and classified as volcanic field (rhyolite) as well as volcanic arc setting. Based on the chondrite normalized spider diagram, LREE has enriched to HREE in this area which indicated negative Eu anomaly and subduction tectonic setting

Studi Awal Geologi di Daerah Beruang Kanan Kabupaten Gunung Mas Propinsi Kalimantan Tengah

The regional tectonic conditions of the KSK Contract of Work are located in the mid-Tertiary magmatic arc (Carlile and Mitchell, 1994) which host a number of epithermal gold deposits (eg, Kelian, Indon, Muro) and significant prospects such as Muyup, Masupa Ria, Gunung Mas and Mirah. Copper-gold mineralization in the KSK Contract of Work is associated with a number of intrusions that have occupied the shallow-scale crust at the Mesozoic metamorphic intercellular junction to the south and continuously into the Lower Tertiary sediment toward the water. This intrusion is interpreted to be part of the Oligocene arc of Central Kalimantan (in Carlile and Mitchell 1994) Volcanic rocks and associated volcanoes are older than intrusions, possibly aged Cretaceous and exposed together with all three contacts (Carlile and Mitchell, 1994) some researchers contribute details about the geological and mineralogical background, and some papers for that are published for the Beruang Kanan region and beyond but no one can confirm the genesis type of the Beruang Kanan region The mineralization of the Beruang Kanan area is generally composed by high yields of epithermal sulphide mineralization. with Cu-Au mineralization This high epithermal sulphide deposition coats the upper part of the Cu-Au porphyry precipitate associated with mineralization processes that are generally controlled by the structur

PEMAHAMAN DAN PENGGUNAAN DATA PENGINDRAAN JAUH DAN SIG PADA EKSPLORASI ENDAPAN MINERAL (SEBUAH RANGKUMAN)

Pengindraan jauh merupakan metode untuk mendapatkan informasi objek permukaan bumi tanpa kontak langsung dengan objek tersebut, Dalam kontek ekplorasi, pengindraan jauh merupakan alat bantu pada pemetaan endapan mineral, meliputi : pemetaan batuan, struktur geologi dan mineral alterasi hidrotermal, Sehingga dapat dikatakan pengindraan jauh menjadi salahsatu alat penting untuk menentukan endapan mineral, terutama kemampuan pengindraan jauh memberikan informasi yang berupa anomali spektral. Adapun alasan parameter yang digunakan berupa pemetaan batuan, umumnya mineralisasi terjadi pada jenis batuan tertentu, begitupula pemetaan struktur, umumnya mineralisasi dikontrol oleh struktur pada arah tertentu, mineralisasi biasanya terjadi di sepanjang atau berbatasan dengan struktur geologi, begitu juga mineral alterasi sangat berperan sebagai penciri dari keberadaan endapan mineral tertentu. Sebagai tambahan, pemahaman data pengindraan jauh hiperspektral maupun multispektral adalah sangat penting karena data hiperspektral maupun multispektral memiliki banyak saluran, dimana tiap saluran mempunyai kemampuan untuk membedakan banyak mineral, sehingga sangat membantu didalam identifikasi dan memetakan secara tematik daerah eksplorasi. Pada tahap akhir eksplorasi, penggunaan SIG (Sistem Informasi Geografi) untuk mengintegrasi, menganalisa serta memanipulasi bermacam-macam data georeference dan geoscience untuk memilih lokasi mineral potensial atau sebagai panduan untuk eksplorasi tingkat lanjut/detil pada tahap berikutnya.Pengindraan jauh merupakan metode untuk mendapatkan informasi objek permukaan bumi tanpa kontak langsung dengan objek tersebut, Dalam kontek ekplorasi, pengindraan jauh merupakan alat bantu pada pemetaan endapan mineral, meliputi : pemetaan batuan, struktur geologi dan mineral alterasi hidrotermal, Sehingga dapat dikatakan pengindraan jauh menjadi salahsatu alat penting untuk menentukan endapan mineral, terutama kemampuan pengindraan jauh memberikan informasi yang berupa anomali spektral. Adapun alasan parameter yang digunakan berupa pemetaan batuan, umumnya mineralisasi terjadi pada jenis batuan tertentu, begitupula pemetaan struktur, umumnya mineralisasi dikontrol oleh struktur pada arah tertentu, mineralisasi biasanya terjadi di sepanjang atau berbatasan dengan struktur geologi, begitu juga mineral alterasi sangat berperan sebagai penciri dari keberadaan endapan mineral tertentu. Sebagai tambahan, pemahaman data pengindraan jauh hiperspektral maupun multispektral adalah sangat penting karena data hiperspektral maupun multispektral memiliki banyak saluran, dimana tiap saluran mempunyai kemampuan untuk membedakan banyak mineral, sehingga sangat membantu didalam identifikasi dan memetakan secara tematik daerah eksplorasi. Pada tahap akhir eksplorasi, penggunaan SIG (Sistem Informasi Geografi) untuk mengintegrasi, menganalisa serta memanipulasi bermacam-macam data georeference dan geoscience untuk memilih lokasi mineral potensial atau sebagai panduan untuk eksplorasi tingkat lanjut/detil pada tahap berikutnya

Geochemical Characteristics of Metamorphic Rock-Hosted Gold Deposit At Onzon-Kanbani Area, Central Myanmar

Gold and associated base metal mineralization of Onzon-Kabani area located in the western border of generally N-S trending Mogoke Metamorphic Belt where well-known Sagaing fault is served as a western boundary of this area. In this research area, many artisanal and small-scale gold mines were noted in last three decades. Gold mineralization is hosted in marble and gneiss unit of research area but most common in marble unit. Variety of igneous intrusions are also observed in research area. Mineralizations are observed as fissure filling veins as well as lesser amount of disseminated nature in marble unit. Mineralogically, gold are associated with other base metal such as pyrite, galena, sphalerite, chalcopyrite, marcasite and arsenopyrite. Hydrothermal alteration halos are developed in peripheral of hydrothermal conduits or mineralization veins from proximal to distal such as 1) silicic, 2) sericite-illite, and 3) propylitic alteration.  Most of hydrothermal minerals from each altered zones showed that near neutral condition of pH (e.g. adularia, calcite, illite, sericite and chlorite). Alternatively, hydrothermal alteration zones that show with ore minerals such as native gold, electrum, sphalerite, galena, chalcopyrite, arsenopyrite and marcasite which mostly observed in silicic alteration zone. Typical boiling characters of vein textures and fluid inclusion petrography are observed in hydrothermal system of research area. Boiling, cooling and mixing are possiblily responsible for gold deposition in hydrothermal system. In this paper, authors are documented to clarify the type of mineralization based on hydrothermal alterations, ore and gangue mineral assemblages and fluid inclusion study. All of these data can describe and play an important role for both with respect to understanding deposit genesis and in mineral exploration

Petrogenetic interpretation of granitoid rocks using multicationic parameters in the Sanggau Area, Kalimantan Island, Indonesia

Granitoid rock compositions from a range of tectonic environments are plotted on a multicationic diagram, based on major and trace element geochemistry and K-Ar dating. This shows that there is a different tectonic nature, rock affinity and suites. The basement granitoid rocks are ranging from diorite to granite composition. They appear to the products of crystallization differentiation of a calc-alkaline magma of island affinity and range to metaluminous granites, granodiorite and tonalite. The tectonic setting has two kinds which are subduction and post-subduction. The geochemical interpretation, origin and melting of mechanism and tectonic setting shows the types of granitoid are M and I-M type. The basement of granite and granodiorite are a segment of island arc that were happened the Sintang Intrusion as post subduction or syn-collision tectonic setting. Keywords: Petrogenetic, tectonic, affinity, Sintang Intrusion, Kalimanta