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All Journal Bulletin of Scientific Contribution : Geology IJOG : Indonesian Journal on Geoscience Journal of Geoscience, Engineering, Environment, and Technology Jurnal Geologi dan Sumberdaya Mineral (Journal of Geology and Mineral Resources) Buletin Sumber Daya Geologi Jurnal Geologi Kelautan: Media Hasil Penelitian Geologi Kelautan Jurnal Sosial Ekonomi Pekerjaan Umum Journal of Geoscience Engineering and Energy (JOGEE) Prosiding Seminar Nasional Rekayasa Teknologi Industri dan Informasi ReTII Aceh International Journal of Science and Technology Jurnal Geologi dan Sumberdaya Mineral (Journal of Geology and Mineral Resources) Journal of Geosciences and Applied Geology
Mega Fatimah Rosana
Faculty of Geology, Padjadjaran University, Jln. Raya Bandung - Sumedang Km. 21
Aerospace Engineering Agriculture, Biological Sciences & Forestry Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics Transportation

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

 1 
Petrogenetic of Igneous Complex of Ilota Nanasi Gold Deposit, Gunung Pani, Gorontalo, Indonesia Rompo, Iryanto; Ismail, Fajar; Santoso, STJ Budi; Rosana, Mega Fatimah; Yuningsih, Euis Tintin
Journal of Geoscience, Engineering, Environment, and Technology Vol. 8 No. 4 (2023): JGEET Vol 08 No 04 : December (2023)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2023.8.4.14250

Abstract

Ilota Nanasi Au-Ag deposit located in the western flank of the Gn. Baganite, a part rhyodacite dome in Gn. Pani district, Gorontalo Province, where the extensive exploration programs were carried out by PT Gorontalo Sejahtera Mining (a subsidiary of PT J Resources Nusantara) from 2012 – 2020.  As the result, a total of 72.7 Mt @ 0.98 g/t Au and 0.85 g/t Ag (2.3 Moz Au and 2.6 Moz Ag) mineral resource was delineated in 2019. This paper mainly aimed to the petrogenesis association of granitoid basement and rhyodacite unit as the host rock in the Ilota Nanasi gold deposit. The geology of Ilota Nanasi is overlain by Late Miocene granodiorite, andesite and diorite basement, Pliocene volcanic complex predominantly dacite – rhyodacite, tuff, breccia, and quaternary deposit as alluvial and surface breccia. Hydrothermal alteration and gold – silver mineralization centered in the porphyritic rhyodacite host rocks where the intense silicification forming a zone around the hydrothermal crackle breccia unit and/or high-density quartz vein, veinlets and stockworks. Mineralization in Ilota Nanasi is interpreted as a low sulfidation epithermal system dominated by a large volume of hydrothermal crackle breccia, intense quartz veining, veinlets, and high-density fracturing. A combined analytical result of petrography and whole-rock geochemistry has been used to assess the petrogenetic association of the rhyodacite and granitoid basement in the Ilota Nanasi. The result of the AFM diagram plot shows sample trends in calc-alkaline magma field. In contrast, the SiO2 – K2O plot distributed in two trends: the older unit was associated with high-K calc-alkaline and the shoshonite series for the younger unit. The changing of magma series is considered as product of crystallization differentiation of evolved parental magma or derived from the melting of mantle material after the mantle or lower crustal was metasomatized during a former episode of subduction.
Geochemistry of Igneous Rocks of Citirem Formation and Its Implications for the Tectonic Setting in Ciletuh – Palabuhanratu UNESCO Global Geopark Area Hafidhah Nurul Haq; Rosana, Mega Fatimah; Endyana, Cipta; Nugraha, Katon Sena Ajie; Alamsyah, Irpan
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.2024.9.1.14367

Abstract

The igneous rocks of the Citirem Formation in the Ciletuh – Palabuhanratu UNESCO Global Geopark area petrographically not only consist of basalt, but also andesite, dacite, and gabbro. The characteristics of basalts Citirem Formation are composed of plagioclase 43% – 58% and olivine, mostly have amygdaloidal and aphanitic textures. Andesites are composed of 45% – 65% plagioclase, absence of olivine, mostly aphanitic and trachytic, some have intergranular textures. Dacite comprises 50% plagioclase, 20% quartz, and the absence of olivine, and aphanitic, intersertal textures. Gabbros are composed of 62% plagioclase, 6% – 12% olivine, with phaneritic texture. Based on the plot of the major elements vs SiO2 diagram, MgO, FeOt (Fe2O3+FeO), CaO, and TiO2 show a negative correlation with SiO2. In comparison, Na2O and K2O show a positive correlation with SiO2. The lithology of igneous rocks of Citirem Formation are basalt, trachybasalt, basaltic trachyandesite, trachyandesite, andesite, dacite and gabbro based on a plot of the Na2O+K2O vs SiO2 diagram for volcanic and plutonic rocks. The origin of magma type can be distinguished based on the plot of K2O vs SiO2 diagrams, the igneous rocks of Citirem Formation are divided into low-K, medium-K, high-K, and shoshonite magma series. Dacite STA 2, andesite STA 7, basaltic andesite STA 8, trachyandesite STA 10 and gabbro STA 14 are calc-alkaline based on triangular diagram Th-Hf-Ta-Zr-Nb. Gabbro STA 17 indicates IAT (island arc tholeiite), trachybasalt STA 19, basalt STA 20 and basaltic trachyandesite STA 27 are E-MORB, WPT (within plate tholeiitic), In contrast, trachybasalt STA 28 is WPA (within plate alkali). Primitive mantle long, NMORB-normalized REE patterns and chondrites-normalized show some rocks have distinctive patterns that have similarities with suprasubduction zone ophiolite rocks, MORB of Mirdita ophiolite, and some show similarities with patterns from OIB and E-MORB.
Geochemistry of Volcanic Rocks in Ponelo Island, North Gorontalo, Indonesia Nurahmah, Siti Chusnul Chatimah; Rosana, Mega Fatimah; Haryanto, Iyan
Journal of Geoscience, Engineering, Environment, and Technology Vol. 9 No. 3 (2024): JGEET Vol 09 No 03 : September (2024)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2024.9.3.16832

Abstract

Ponelo Island is located in the northern part of Sulawesi, which is still an enigma regarding the genesis of the volcanic rocks found on this island. Therefore, the objective of this study is to understand the petrogenesis and tectonic implication of these volcanic rocks. Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) to obtain trace and rare earth elements is the method of this study. The volcanic rocks found on Ponelo Island consist of basalt and basaltic andesite rocks with a calc-alkaline affinity. The transition data suggested a highly fractionated cause of low transition element (Ni=17-38 ppm; Cr=13-47) compared to primary magma concentration, anomalies negative of Ba, Sr, and Ti of spider diagrams, and negative anomaly of Eu (Eu/Eu*=0.88-0.99). Relationship between low concentration between Ce/Y (0.74-0.76) and La/Yb vs Sm/Yb ratio indicated ~5% spinel-lherzolite mantle source partial melting. On the other hand, incompatible element ratios, such as Ba/Nb (39.03-45.28), Ba/Th (75.52-82.67), Rb/Nb (3.93-6.22), K/Nb (1772.22-2703.45), Ba/La=13.67-14.57, Th/La (0.17-0.18), La/Nb (2.91-3.16), depleted Nb/U (6-6.74), and also lack of xenolith or enclaves indicate cryptic crustal contamination.  The slab-derived fluid indicated by ratios of Rb/Y (0/019-0/05), Nb/Y (0.10-0.11), Th/Yb (0.52-0.61), and Ba/La ratio (13.29-14.57). Ponelo volcanic rocks shows typical calc-alkaline island arc tectonic setting particularly with enrichment in ion lithophile element (LILE) and light rare earth elements (LREE) along with depletion in high field strenght elements (HFSE) and heavy rare earth elemets (HREE), as shown by spider diagrams.
Co-Authors Achmad Noerkhaerin Putra Achmad Rizal Adi Hardiyono, Adi Adjat Sudradjat Adjat Sudrajat Agus Didit Haryanto -, Agus Didit Haryanto Akhmad Fauzan Alamsyah, Irpan Almun Madi Andi Kurniawan Angga Syahputra, Muhammad Eko Ar-rouf, Ferdian Budi Arie Noor Rakhman Asri Arifin Asrial, Nouval Muamar Aton Patonah, Aton Azzaenuri, Mohammad Fachri Bahtiar, Wisnu Indra Bensaman, Benny Boy Yoseph Cahya Sunan Sakti Syah Alam Cecep Yandri Sunarie, Cecep Yandri Chiyonobu, Shun Cipta Endyana Dicky Muslim Diwantara, Raja Hertansyah Eko Tri Sumarnadi Agustinus Emi Sukiyah Ernowo Ernowo Euis Tintin Yuningsih Fachrudin, Kurnia Arfiansyah Fadhlurrohman Putrananda, Aditya Faizal, Reza Mochammad Faizal, Reza Mochammad Faurine, Nurul Rizma Fitriany, Ria Fivry Wellda Maulana Hafidhah Nurul Haq Heriawan, Mohammad N Hernadi, Deni Heru Sigit Purwanto Hill Gendoet Hartono Hiroharu Matsueda Ildrem Syafri Indra Kusuma, Riko Ardiansyah Indrakususma, Riko Ardiansyah Indrakususma, Riko Ardiansyah Ismail, Fajar Iyan Haryanto, Iyan Johanes Hutabarat Kamaruddin, Hashari Kamaruddin, Hashari Kemala Wijayanti, Kemala Khoerunisa, Resa Kurnia Arfiansyah, Kurnia Lia Jurnaliah Lili Fauzielly Marbun, Ardiansyah Maulana, Muhammad Hafidz Meiriyanto, Fernandy Mohamad Nur Heriawan Muhammad Hery Setiyawan Nana Sulaksana Nordin, Nazihah Nugraha, Katon Sena Ajie Nurahmah, Siti Chusnul Chatimah Nurzakiyah, Halimah Pradnya Paramarta Raditya Rendra Pratiwi, Prisca Nurul Purwaiswanto, Bambang Antoro Putri, Nisrina Nadellia Raden Isnu Hajar Sulistyawan, Raden Isnu Hajar Rangga Suteja, Rangga Rezky, Yuanno Rezky, Yuanno Ridho Kresna Wattimena Ridho Kresna Wattimena, Ridho Kresna Rinawan, Fiandri Indragunawan Rinawan, Fiandri Indragunawan Rompo, Ahmad Iryanto Rompo, Iryanto Ruswanto, . Santoso, STJ Budi Saputra, Dwie H. Sentosa*, Millati Amalia Soepriadi, Soepriadi Soepriadi, Soepriadi Sukaesih Sukaesih, Sukaesih Sukardan Tawil SUMARWAN, FIRMAN Suwandhi, Awang Suwandhi, Awang SYAH, MOHAMAD AKBAR Tampubolon, Armin Undang Mardiana Wibowo, Setiyo Widyariestha, Mira Winantris Winantris Wirdan, Muhammad Faisal Yanuar, Yerry Yuningsih, Euis Tintint Zakaria, Zulfiadi Zuzy Anna