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"Indonesia memiliki keunggulan di sektor pertambangan, dengan sumberdaya mineralnya yang melimpah, salah satunya adalah nikel. Menurut data Kementrian ESDM pada tahun 2020, cadangan nikel Indonesia, sebagian besar 90% tersebar di daerah Sulawesi Tenggara, Sulawesi Tengah, Sulawesi Selatan, dan Maluku Utara. Daerah penelitian berlokasi di Kabupaten Halmahera Timur, Maluku Utara dengan tipe deposit atau endapan nikelnya adalah tipe endapan nikel laterit yang berasal dari batuan dasar Komplek Batuan Ultrabasa Halmahera (Ub). Batuan dasar pada endapan nikel laterit, memiliki peranan penting dalam menghasilkan karakteristik endapannya. Namun sampai saat ini penelitian mengenai hal tersebut masih jarang ditemukan terutama pada daerah penelitian sehingga menarik untuk dilakukan studi lebih lanjut. Penelitian ini bertujuan untuk mengetahui karakteristik endapan nikel laterit yang dihasilkan dari jenis batuan dasar yang berbeda, serta potens unsur yang ada. Penelitian diawali dengan klasifikasi batuan induk analisis petrologi, petrografi, dan statistik deskriptif dari data geokimia, kemudian dilanjutkan dengan memodelkan kadar Ni menggunakan metode interpolasi Inverse Distance Weighting (IDW). Hasil penelitian didapati bahwa daerah penelitian tersusun atas batuan ultramafik harzburgit dan dunit. Dari hasil analisis data geokimia pada setiap lapisan, didapati bahwa persentase nikel tertinggi terdapat pada lapisan saprolit yang dihasilkan dari batuan dasar dunit dengan kemiringan lereng dominan sangat landai.

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Indonesia has an advantage in the mining sector, with its abundant mineral resources, one of which is nickel. According to data from the Ministry of Energi and Mineral Resources in 2020, most of Indonesia's nickel reserves, 90% are scattered in Southeast Sulawesi, Central Sulawesi, South Sulawesi and North Maluku. The research area is located in East Halmahera Regency, North Maluku with the type of nickel deposit or deposit being laterite nickel deposit type originating from the bedrock of the Halmahera Ultrabasic Rock Complex (Ub). The bedrock in laterite nickel deposits has an important role in producing the characteristics of the deposit. However, until now research on this matter is still rarely found, especially in the research area, so it is interesting to conduct further studies. This study aims to determine the characteristics of laterite nickel deposits produced from different types of bedrock, as well as the potential of the elements present. The study begins with the classification of the source rock with petrological analysis, petrography, and descriptive statistics from geochemical data, then proceeds with modeling the levels of Ni using the Inverse Distance Weighting (IDW) interpolation method. The results showed that the study area is composed of ultramafik harzburgite and dunite rocks. From the analysis of geochemical data for each layer, it was found that the highest percentage of nickel was found in the saprolite layer produced from dunite bedrock with a very gentle dominant slope."

"Daerah Ganda-Ganda, Morowali Utara merupakan salah satu daerah penghasil bijih nikel di Indonesia dari endapan laterit. Endapan laterit tersebut dihasilkan dari pelapukan batuan ultramafik (batuan asal). Pada area penelitian terdapat pada Komplek Ultramafik dari Jalur Ofiolit Sulawesi. Penelitian ini bertujuan untuk mengetahui komposisi endapan laterit, karakteristik batuan ultramafik, dan asosiasinya terhadap tektonik dari sampel batuan asal daerah penelitian. Metode yang digunakan yakni analisis petrografi, X-Ray diffraction (XRD), dan energy dispersive X-Ray fluorescence (EDXRF). Profil terdiri atas limonit dan saprolit hingga rocky saprolite. Komposisi mineral profil limonit didominasi goetit dan gibbsit. Saprolit didominasi antigorit, talk, lizardit, dan nakrit. Batuan asal didominasi mineral silikat. Jenis batuan ultramafiknya meliputi lherzolit terserpentinisasi, harzburgit terserpentinisasi, olivin websterit terserpentinisasi, dan serpentinit. Secara geokimia semua batuan ultramafik berkomposisi lherzolit. Semua batuan hadir mikrotekstur mesh. Banyak mineral olivin dan piroksen di batuan asal telah terubah menjadi mineral serpentin. Mikrotekstur serpentinit mencangkup tekstur mesh pada lizardit, tekstur relict pada olivin, tekstur veinlet mineral krisotil, dan tekstur decussate mineral antigorit. Komposisi batuan asal dominan tersusun atas mineral olivin, lizardit, dan piroksen. Batuan ultramafik daerah penelitian berasosiasi dengan tektonik supra-subduction zone (SSZ) yang dominan hingga mid-oceanic ridge basalt (MORB) dengan seri magma tholeiite.

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The Ganda-Ganda area, North Morowali is one of the nickel ore producing areas in Indonesia from laterite deposits. Laterite deposits are produced from the weathering of ultramafic rocks (source rocks). The research area is in the Ultramafic Complex of the Sulawesi Ophiolite Belt. This research aims to determine the composition of laterite deposits, the characteristics of ultramafic rocks, and their association with tectonics from the source rock samples from the research area. The methods used are petrographic analysis, X-ray diffraction (XRD), and energy-dispersive X-ray fluorescence (EDXRF). The profile consists of limonite and saprolite to rocky saprolite. The mineral composition of the limonite profile is dominated by goethite and gibbsite. Saprolite is dominated by antigorite, talc, lizardite, and nacrite. The source rocks are dominated by silicate minerals. Ultramafic rock types include serpentinized lherzolite, serpentinized harzburgite, serpentinized olivine websterite, and serpentinite. Geochemically, all ultramafic rocks fall in the lherzolite composition. All rocks have mesh microtexture. Many of the olivine and pyroxene minerals of the source rock have been altered into serpentine minerals. Serpentinite microtextures include the mesh texture of lizardite, the relict texture of olivine, the veinlet texture of chrysotile, and the decussate texture antigorite. The dominant composition of the source rocks consists of olivine, lizardite and pyroxene minerals. Ultramafic rocks in the study area are dominantly associated with supra-subduction zone (SSZ) tectonics to mid-oceanic ridge basalt (MORB) with a tholeiite magma series."

"Cadangan nikel laterit di nusantara tersebar pada wilayah Indonesia bagian tengah karena berasosiasi dengan jalur ultramafik. Pulau Pakal yang berada di Kabupaten Halmahera Utara, Provinsi Maluku Utara menjadi salah satu daerah dengan prospek nikel laterit yang baik. Penelitian ini bertujuan untuk mengidentifikasi batas antar zona laterit Pulau Pakal menggunakan korelasi metode resistivitas dengan konfigurasi Wenner dan data bor. Metode resistivitas digunakan untuk mengukur nilai tahanan jenis batuan laterit yang kemudian akan dikorelasikan dengan data bor untuk meningkatkan akurasi analisis yang akan dilakukan. Pengolahan data resistivitas dilakukan menggunakan perhitungan matematika inversi 2-D untuk menghasilkan penampang true resistivity 2-D. Selain itu dilakukan pengolahan data bor yang kemudian akan menghasilkan model penampang bor pada lintasan pengukuran. Hasil penelitian ini adalah integrasi penampang dari batasan antar zona laterit yang ditentukan berdasarkan respon resistivitas lintasan dan informasi litologi yang dihasilkan dari analisis unsur kimia pada data bor. Penampang integrasi lintasan 19 menunjukkan adanya perbedaan dalam menentukan batasan zona limonit dan saprolit berdasarkan nilai resistivitas dan data bor. Terdapat asosiasi air yang cukup signifikan pada zona limonit lintasan 19 yang membuat respon resistivitasnya menjadi lebih rendah daripada zona saprolit. Sebaliknya, penentuan batasan zona saprolit dan bedrock pada lintasan tersebut justru menunjukkan korelasi yang cukup baik. Penampang integrasi lintasan 20 menunjukkan korelasi yang baik antar respon resistivitas dan data bor di mana penentuan batasan zona laterit keduanya berada di kedalaman yang relatif sama.

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The lateritic nickel reserves in the archipelago are distributed in the central part of Indonesia due to their association with ultramafic belts. Pulau Pakal, located in North Halmahera Regency, North Maluku Province, is one of the areas with good lateritic nickel prospects. This study aims to identify the boundaries between lateritic zones in Pulau Pakal using the correlation of resistivity methods with the Wenner configuration and borehole data. The resistivity method is used to measure the resistivity values of laterite rocks, which are then correlated with the borehole data to improve the accuracy of the analysis. The processing of resistivity data is done using 2-D inversion mathematical calculations to generate 2-D true resistivity sections. Additionally, the borehole data is processed to create a borehole cross-sectional model along the measurement path. The result of this study is the integration of cross-sections indicating the boundaries between lateritic zones, which are determined based on the resistivity response along the profile and lithological information obtained from the chemical analysis of the borehole data. The integration cross-section of profile 19 shows differences in determining the boundaries between the limonite and saprolite zones based on resistivity values and borehole data. There is a significant water association in the limonite zone of profile 19, which causes its resistivity response to be lower than that of the saprolite zone. Conversely, the determination of the saprolite and bedrock boundaries in that profile shows a fairly good correlation. The integration cross-section of profile 20 shows a relatively good correlation between resistivity response and borehole data, where the boundaries of both lateritic zones are at a similar depth."

"Hutan berfungsi sebagai penyerap karbon dan menyimpannya dalam bentuk biomassa hutan, untuk itu diperlukan teknik yang efektif dan mudah digunakan dalam menduga cadangan karbon pada suatu hamparan vegetasi. Penelitian ini bertujuan untuk mengetahui estimasi stok karbon di area hutan Halmahera Timur serta sebarannya menurut karakteristik fisik hutan. Estimasi stok karbon diperoleh dari hubungan keterkaitan antara diameter batang, tinggi pohon kerapatan vegetasi, dan biomassa yang dihitung melalui model Alometri dengan nilai NDVI citra Landsat TM, sehingga dari hubungan tersebut diperoleh sebaran stok karbon di area hutan Halmahera timur.Dari hasil pengolahan sebaran stok karbon tertinggi terdapat pada kerapatan vegetasi rapat dengan persentase nilai sebesar 52,20%, sedangkan untuk sebaran stok karbon berdasarkan kelerengan nilai tertinggi terdapat pada kelerengan 16-25%, untuk sebaran stok karbon tertinggi berdasarkan ketinggian terdapat pada ketinggian 501-750, dan untuk sebaran stok karbon tertinggi berdasarkan jenis tanah terdapat pada tanah latosol.

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Forests serve as carbon sinks and store it in the form of forest biomass, it is necessary for effective technique and easy to use in suspected carbon stocks on a carpet of vegetation. This study aims to determine the estimated carbon stocks in forest areas of East Halmahera and distribution according to physical characteristics of forest. Estimated carbon stocks derived from the relationship between stem diameter, tree height vegetation density, and biomass are calculated through Algometry model with Landsat TM NDVI values, so that the relationship obtained distribution of carbon stocks in forest area east of Halmahera.

The results have the highest carbon stock distribution on the density of vegetation meeting with the percentage value of 52.20%, while for the distribution of carbon stocks based on the steepness of the highest value found in 16-25% slope, for the distribution of the highest carbon stocks based on height are at an altitude of 501 - 750, and to the highest carbon stock distribution by type of soil found on the ground latosol."

"Keuntuhan lereng batuan merupakan kasus kelongsoran yang memerlukan analisis khusus, sehingga menimbulkan antusias untuk melakukan analisis berdasarkan metode elemen hingga. Metode tersebut dianggap paling memiliki sensitivitas yang baik. Dalam melakukan analisis perlu direncanakan pemodelan yang dianggap tepat dalam memodelkan geometri antar batuan utuh dan model konstitutif yang merepresentasikan kondisi batuan aslinya. Digunakan model geometri yang merepresentasikan jenis kelongsoran guling khususnya dalam memodelkan diskontuniutas celah antar batuan utuh. Model geometri yang digunakan adalah model dengan elemen area kecil bersudut 60̊ berlawanan jarum jam. Model konstitutif yang digunakan untuk memodelkan lereng batuan adalah Mohr-Coulomb. Ada beberapa faktor yang diprediksi dapat mempengaruhi keruntuhan lereng, diantaranya pengaruh pemotongan lereng karena pekerjaan konstruksi dan kondisi muka air tanah. Tujuan penelitian ini untuk mendapatkan pemodelan yang optimal pada analisis kelongsoran lereng batuan menggunakan media perangkat Midas GTS NX.

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The failure of rock slopes is a landslide case that requires special analysis, so that it creates enthusiasm to carry out an analysis based on the finite element method. This method is considered to have the best sensitivity. In conducting the analysis, it is necessary to plan a model that is considered appropriate in modeling the geometry between intact rocks and a constitutive model that represents the original rock condition. A geometric model is used that represents the type of toppling failure, especially in modeling the jointed rock. The geometry model used is a model with a small area element at an angle of 60̊ counterclockwise. The constitutive model used to model rock slopes is Mohr-Coulomb. There are several factors that are predicted to affect slope failure, including the effect of cutting slopes due to construction work and ground water level conditions. The purpose of this study was to obtain optimal modeling of rock slope slide analysis using sotfware Midas GTS NX."

"Daerah penelitian secara administratif berada di daerah Ganda-Ganda, KecamatanPetasia, Kabupaten Morowali Utara, Provinsi Sulawesi Tengah. Pelapukan batuanultramafik menghasilkan endapan laterit dengan karakteristik yang berbeda disetiapdaerah. Penelitian ini bertujuan untuk mengetahui karakteristik mineralogi dan geokimiaendapan nikel laterit dan batuan dasar, serta derajat laterisasi dan distribusinya padadaerah penelitian. Data yang digunakan merupakan data lapangan dari 6 profil lateritberupa 39 sampel batuan dan tanah, serta data assay dari analisis XRF (X-RayFluorescence) dan XRD (X-Ray Diffraction). Profil laterit pada daerah penelitian terdiridari limonit dengan kadar Ni 0,2 – 0,47%, serta saprolit 0,23 – 0,89% (termasuk sampelbedrock). Sampel bedrock yang merupakan bongkah batuan disekitar lapisan saprolitsecara mineralogi dianggap mewakili batuan dasar di bawah permukaan, memiliki kadarNi 0,56 – 0,89% dan diinterpretasikan merupakan rocky saprolite. Nikel pada limonitsecara dominan berasosiasi dengan mineral goetit dan gibsit, sementara pada saprolitberasosiasi dengan mineral serpentin (lizardit dan antigorit), talk, olivin (forsterit danfayalit), dan piroksen (enstatit). Derajat laterisasi pada daerah penelitian menunjukkanlimonit mengalami moderate – strongly lateritized, saprolit kaolinitized – stronglylaterized dan Index of laterization (IOL) berkorelasi positif dengan hubungan korelasikuat terhadap Fe pada limonit, saprolit, dan bedrock, sementara berkorelasi negatifterhadap Ni dengan hubungan lemah pada sampel bedrock.

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The research area is administratively located in Ganda-Ganda, Petasia District,

North Morowali Regency, Central Sulawesi Province. Weathering of ultramafic rocks

produces laterite deposits with different characteristics in each area. This study aims to

determine the mineralogical and geochemical characteristics of nickel laterite deposits

and bedrock, as well as the degree of laterization and its distribution in the research area.

The data used include field data from 6 laterite profiles consisting of 39 rock and soil

samples, as well as assay data from XRF (X-Ray Fluorescence) and XRD (X-Ray

Diffraction) analyses. The laterite profiles in the study area consist of limonite with Ni

content of 0.2 – 0.47%, and saprolite with Ni content of 0.23 – 0.89% (including bedrock

samples). The bedrock samples, which are rock fragments around the saprolite layer, are

mineralogically considered to represent the bedrock beneath the surface, with Ni content

of 0.56 – 0.89% and are interpreted as rocky saprolite. Nickel in limonite is predominantly

associated with the minerals goethite and gibbsite, while in saprolite it is associated with

serpentine minerals (lizardite and antigorite), talc, olivine (forsterite and fayalite), and

pyroxene (enstatite). The degree of laterization in the study area shows that limonite is

moderately to strongly lateritized, saprolite is kaolinitized to strongly laterized, and the

Index of Laterization (IOL) positively correlates with Fe in limonite, saprolite, and

bedrock, while it negatively correlates with Ni with a weak correlation in bedrock

samples."

"Prediksi tekanan pori merupakan hal yang penting dalam persiapan program pemboran, khususnya jika diprediksi menembus zona gas dangkal. Program pemboran akan mempengaruhi saat penentuan desain selubung pemboran, berat lumpur dan mitigasi tekanan abnormal sebagai bahaya pemboran. Di lapangan ?B?, Cekungan Sumatera Tengah beberapa sumur mengalami tendangan lumpur (kick). Kejadian tersebut yang melatar belakangi studi tekanan pori untuk pemboran selanjutnya. Studi ini ditekankan pada teknik integrasi prediksi tekanan pori dari data sumur, yaitu data pemboran, wireline log, data tekanan formasi dan data seismik 2-D. Saat ini, teknologi seismik dengan dasar teknik geopressure dapat memberikan estimasi tekanan dari data kecepatan seismik dikombinasikan dengan data sumur memiliki tren yang sama. Studi ini menggunakan hasil analisa kecepatan seismik untuk mendapatkan resolusi tinggi kecepatan dalam tiga dimensi. Tahap kalibrasi dilakukan berdasarkan hasil perhitungan tekanan pori dari data sumur dan well log. Metoda Eaton merupakan metoda empiris untuk mengestimasi tekanan pori data log sonik, resistivitas, dan densitas yang dikalibrasi dengan pengukuran tekanan formasi dari data RFT dan DST. Prediksi tekanan pori di Lapangan ?B? dilakukan dapat membuat prediksi di seluruh area lapangan dan berguna dalam desain selubung pemboran, berat lumpur, dan pencegahan untuk drilling hazard.

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Pore Pressure Prediction is crucial to prepare a safe drilling program especially if there the well will potentially intersect shallow gas zones. It influences casing design, drilling mud weight and mitigation of overpressure as a drilling hazard. In the "B" Block, Central Sumatra Basin several wells have experienced kicks. These kicks led me to conduct a pore pressure study ahead of future drilling. The work more emphasize the technique integrated pore pressure prediction (PPP) brings together well and 2-D seismic data. The study used as input data from drilling data, wireline logs, pressure tests,and 2D Seismic.

Nowadays, seismic technology-based geopressure techniques provide an estimation of pore pressure from seismic velocity combine with well data has a relation in trend.

This study uses velocity analysis result to obtain a high-resolution velocity cube. Afterward, calibrated to pore pressure using well log and drilling data. The Eaton method is an empirical method to estimate pore pressures from sonic, resistivity and density logs which are calibrated to measured pore pressures from RFT and DST. In the "B" Block, the resistivity data did not reliably characterize pore pressure, and density data was incomplete, so the sonic log proved to be the most appropriate source data. Reliable pore pressure distribution required an empirical relationship between pore pressure and velocity. The Bentu Block pore pressure model created in this study allowed us to predict pore pressure throughout the block, and was used to design a drilling program especially for propose delineation wells, casing design, drilling mud weight, and overpressure prediction to prevent drilling hazards."

"Pulau Ternate merupakan pulau vulkanik yang terbentuk dari tubuh Gunung Gamalama. Litologi di pulau ini didominasi oleh produk-produk vulkanik hasil erupsi gunung berapi. Akan tetapi, belum ada penelitian mengenai karakterisasi produk vulkanik dan sumbernya. Penelitian ini bertujuan untuk mengidentifikasi karakteristik endapan piroklastik, proses, dan mekanisme erupsi pada saat pembentukan endapan piroklastik di daerah penelitian. Metode yang digunakan dalam penelitian ini adalah Grain Size Distrubution (GSD) dan analisis komponen. Hasil penelitian menghasilkan data komponen pumice sebanyak tujuh jenis dan lithic sebanyak empat jenis. Mekanisme pengendapan yang membentuk endapan piroklastik merupakan pyroclastic fall. Terdapat setidaknya tiga kali fase erupsi yang membentuk endapan piroklastik, yaitu fase erupsi Gunung Telaga dan dua fase erupsi Gunung Gamalama yang ditandai dengan persebaran komponen.

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Ternate Island is a volcanic island formed from the body of Mount Gamalama. The lithology of island is dominated by the volcanic products of the volcano eruption. However, no research has been done on the characterization of volcanic products and their sources. The study aims to identify the characteristics of pyroclastic deposits, processes, and eruption mechanisms at the time of the formation of pyroclastic deposits in the research area. The methods used in this study are Grain Size Distrubution (GSD) and component analysis. The results of the research resulted in data on the components of the pumice as many as seven types and the lithic as four types. The sedimentary mechanism that forms the pyroclastic deposits is a pyroclastic fall. There are at least three phases of the eruption that form the pyroclastic deposits, namely Mount Telaga's eruptive phase and two Phases of Mount Gamalama's Eruption characterized by the spread of components."

"Pulau Sulawesi merupakan salah satu pulau dengan deposit nikel laterit terbesar di Indonesia, yang berkaitan erat dengan keberadaan East Sulawesi Ophiolite (ESO). Deposit nikel laterit merupakan hasil dari pelapukan batuan ultramafik yang ditemukan pada sekuen ofiolit, sehingga mengalami pengayaan unsur tertentu pada setiap profil laterit. Penelitian mengenai hubungan antara batuan induk terhadap karakteristik deposit nikel laterit yang dihasilkan masih jarang ditemukan sehingga sangat menarik untuk diteliti lebih lanjut. Penelitian ini bertujuan untuk mengetahui batuan induk serta kaitannya terhadap karakteristik deposit nikel laterit yang terdapat di Kabupaten Konawe, Sulawesi Tenggara tepatnya di lapangan DS. Penelitian diawali dengan klasifikasi batuan induk berdasarkan data geokimia XRF dengan menggunakan pembelajaran mesin tersupervisi yang kemudian dilanjutkan dengan analisis petrografi dan mikro XRF pada setiap tipe batuan dasar yang ditemukan. Berdasarkan hasil penelitian, diketahui bahwa daerah penelitian tersusun atas batuan ultramafik harzburgit tipe 1, 2 dan 3 yang dibedakan berdasarkan komposisi mineral utama. Dari hasil analisis data XRF setiap zona, didapatkan hasil bahwa persentase nikel tertinggi ditemukan pada profil saprolit lunak pada zona harzburgite tipe tiga yang didukung oleh kondisi kemiringan lereng.

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Sulawesi is one of the islands with the largest nickel laterite deposits in Indonesia, which is closely related to the existence of East Sulawesi Ophiolite (ESO). Laterite nickel deposit is the result of weathering of ultramafic rocks found in ophiolite sequences, with certain element enrichment in each laterite profile. Research on the relationship between the source rock and the characteristics of the laterite nickel deposit is still rarely found, so it is very interesting for further research. This study aims to determine the source rock and its relation to the characteristics of laterite nickel deposits in Konawe Regency, Southeast Sulawesi, precisely in the DS field. The study began with the classification of the bedrock based on XRF geochemical data using supervised machine learning which was continued with petrographic and micro XRF analysis for each type of bedrock. Based on the research results, it is known that the research area is consisted of ultramafic harzburgite rocks types 1, 2 and 3 which are differentiated based on the composition of the major minerals. From the analysis of XRF data for each zone, the result shows that the highest percentage of nickel was found in the soft saprolite profile in the Harzburgite zone type three which was supported by morphological conditions."