The mining development is influences the economy growth and support to increases the society prosperity. East Belitung be able to execute the mining development which have some potential mining resources such tin, galena, iron ore, bauxite, granite, quartz sand, and kaolin. The research method is field observation to find out the geological condition and the mining material resources along with GIS analysis for representation the geomorphology and geology in East Belitung. East Belitung geomorphology consist of plains and hills with elevation more than 600 msl. The plain area is used for tin exploration and oil palm plantation, while the hill area for protected forest. East Belitung geology consist of alluvium, carbon sand, Tajam Formation, Kelapakampit Formation, Siantu Formation, Tanjungpandan Granite, Baginda Adalemite, Burungmandi Granodiorite, Batubesi Quartz Diorite. The geology structure in East Belitung are fold, fault and crack. Generally, the fold direction is NW-SE, the fault direction is NE-SE. Based on geochemical analysis and the distribution of mining material resources can be concluded that East Belitung area have large potential of mining material resources, it seen from galena, iron ore and bauxite materials that have intermediate until good quality. Besides that, from the delineation of potential distribution map shown the mining material have extensive distributions and can be optimization for regional development and society prosperity. Keywords : Mining Material, East Belitung, Delineation of Potential Distribution, Mining ABSTRAKPerkembangan area pertambangan sangat berpengaruh kepada pertumbuhan ekonomi suatu daerah dan membantu dalam peningkatkan kesejahteraan masyarakat. Salah satu daerah yang dapat melakukan pengembangan area pertambangan adalah Belitung Timur yang memiliki beberapa potensi bahan galian antara lain timah, galena, biji besi, bauksit, granit, pasir kuarsa, dan kaolin. Metode penelitian berupa pengamatan lapangan untuk mengetahui kondisi geologi dan sumberdaya bahan galian serta analisis GIS untuk mendapatkan gambaran geomorfologi dan geologi Kepulauan Belitung. Geomorfologi pada daerah Belitung Timur berupa pedataran dan perbukitan yang ketinggiannya berada diatas 600 mdpl. Pedataran lebih banyak dipergunakan untuk penambangan timah dan perkebunan sawit, sedangkan perbukitan dimanfaatkan untuk hutan lindung. Geologi pada daerah Belitung Timur terdiri dari Aluvium, Pasir berkarbon, Formasi Tajam, Formasi Kelapakampit, Formasi Siantu, Granit Tanjungpandan, Adalemit Baginda, Granodiorit Burungmandi, Diorit Kuarsa Batubesi. Struktur geologi yang berkembang pada kawasan ini adalah lipatan, sesar dan kekar .Arah sumbu lipatan umumnya Baratlaut-Tenggara, sedangkan sesar berarah Timurlaut-Baratdaya. Berdasarkan analisis geokimia dari sampel lapangan dan sebaran dari bahan galian yang ada dapat disimpulkan bahwa daerah kawasan Belitung Timur memiliki potensi bahan galian yang besar, terlihat dari kandungan bahan galian galena, biji besi, dan bauksit yang memiliki kadar menengah hingga tinggi. Selain itu, dari hasil deliniasi sebaran potensi memperlihatkan sebaran bahan galian berpotensi yang berada pada kawasan Belitung Timur sangat besar dan dapat dioptimalisasi agar berguna untuk pembangunan dan peningkatan kesejahteraan masyarakat. Kata kunci : Bahan Galian, Belitung Timur, Deliniasi Sebaran Potensi, Pertambangan.

Gunung Badak area, Ciletuh Bay, Sukabumi is area that has a rare diversity of rock at West Java region. Morphology of this area is interesting enough for one of the aspects of tourism, especially geological asptect (geotourism).This reveals the general geotourism potential in the Ciletuh Bay area. Method used in this study is a survey directly in the field and a review of some aspects of the geological literature Ciletuh. There are three groups of objects geotourism that can be developed in this area, namely: Amphiteater Morphology of Ciletuh Bay; Mandra Island; Manuk Island; Kunti Island and Lava pillows; G. Badak and G. Aseupan.Management and effective supervision are required to develop this potential to be geotourism, considering this area is part of Nature Reserve Cibanteng. Development potential to the south towards Ujung Genteng geotourism quite well developed for tourism towards the coast, and the green turtle protection.

Daerah Aliran Sungai (DAS) Citarik Bagian Hulu secara administratif berada di Kabupaten Bandung dan sebagian Kabupaten Sumedang. Sungai Citarik merupakan anak dari Sungai Citarum yang melewati beberapa daerah seperti Cicalengka dan Rancaekek. Perkembangan wilayah yang pesat didaerah yang dilewati oleh Sungai Citarik ini menyebabkan sering terjadinya banjir saat musim hujan. Banjir yang terjadi didaerah ini selain disebabkan karena perubahan tutupan lahan yang masif juga dipengaruhi oleh faktor alamiah seperti peningkatan curah hujan dan faktor morfologi dari Sungai Citarik itu sendiri. Daerah penelitian dibagi menjadi 20 daerah tangkapan air (catchment area). Tujuan dari penelitian ini adalah untuk mengetahui tingkat kerentanan potensi banjir berdasarkan analisis morfometri. Parameter morfometri yang digunakan yaitu rasio kebundaran (Rc), kerapatan pengaliran (Dd), gradien sungai, dan kemiringan lereng. Parameter tersebut sebagai aspek kuantitatif bentuk lahan. Selain itu, parameter curah hujan dan penggunaan lahan juga digunakan sebagai parameter penentuan kerentanan banjir pada daerah penelitian. Hal ini ditunjukkan dengan hasil analisis karakteristik morfometri pada daerah penelitian memiliki bentuk DAS membundar - memanjang, kerapatan pengaliran sedang, gradien sungai rendah, curah hujan agak rendah, dan kemiringan lereng yang bervariasi dari datar-sangat curam. Terdapat 3 tingkat kerentanan banjir di daerah penelitian yaitu Wilayah Tidak Rentan di sebelah utara dan selatan daerah penelitian, Wilayah Sedikit Rentan pada bagian utara hingga selatan, dan Wilayah Agak Rentan pada bagian barat hingga tenggara daerah penelitian.

ABSTRACTGeoelectric measurement was done in order to obtain the presence, depth, thickness, quantity and distribution of aquifers in the study area. Geoelectric was done by applying 1-D Schlumberger configuration (DC sounding). Rock layer with a resistivity value ranges <20 μm indicates rocks with low resistance values, dominates the surface until 50 meters depth with varying thickness. This layer lithology thought to be composed of weathered soil, fine tuff and lapilli tuff. This layer is assumed to act as aquiclude, porous media that can store water but acts as barrier to the flow of groundwater. This lithology group can be filled by water during the rainy season, but in dry season contain very small amount of water. Rock layer with resistivity value ranges between 20 μm - 60 μm interpreted as coarse tuff intercalating with fine tuff, founded at 75 meters depths below the surface. Rock layers with high resistance values (> 60 μm), founded more than 75 meters in the north area, assumed to be volcanic breccia with tuff as matrix, and have small potential to act as aquifer. Keyword: Geoelectric, Schlumberger, Aquifer, Resistivity ABSTRAKPengukuran geolistrik yang dilakukan dalam upaya untuk mendapatkan kehadiran, kedalaman, ketebalan, jumlah dan penyebaran akuifer. Hasil  pengukuran geolistrik (Sounding) dengan konfigurasi Schlumberger Kelompok batuan dengan nilai tahanan jenis berkisar antara  <20 Wm yang mengindikasikan batuan dengan nilai tahanan jenis rendah mendominasi permukaan hingga kedalaman 50 meter dengan ketebalan bervariasi. Lapisan ini diduga memiliki litologi penyusun terdiri atas tanah lapukan, tuf halus dan tuf lapili. Lapisan ini diduga berperan sebagai akiklud, yaitu media berpori yang dapat menyimpan air tetapi tidak dapat mengalirkan airtanah yang dapat terisi oleh air pada musim hujan, namun pada musim kering tidak mengandung air. Lapisan batuan dengan nilai tahanan jenis antara 20 Wm - 60 Wm  diinterpretasi litologi tuf kasar berselingan dengan tuf halus, berada pada kedalaman mulai 75 meter di bawah permukaan. Lapisan batuan dengan nilai tahanan jenis tinggi (>60 Wm), mulai di kedalaman lebih dari 75 meter di bagian utara diperkirakan breksi vulkanik dengan matriks berupa tuf, dan memiliki potensi kecil sebagai akuifer. Kata Kunci: Geolistrik, Schlumberger, Akifer, Resistivitas

The northern part Cianjur based on the Regional Hazard Map of Mount Gede in West Java (kaswanda, 1994) is an explosion hazard areas. The rapid economic development, especially in the tourism sector resulting in increased occupancy, hotel or villa. As a result of the growth area of the building, and the increase of population, and transfer of land use, has resulted in the handling of the impact so that the necessary pre-disaster management in which one of them is a disaster mitigation. Determination of the level of risk is one basis for determining mitigation measures related to spatial planning. The main risk factors of natural disasters include volcanic eruption hazard factors, vulnerability and resilience. Factors will affect the hazard mitigation measures that will be done in the danger area. The primary hazard mitigation in the area would have been different in the secondary area. Thus the delineation is an important step that must be done before determining the level of risk. Determination of the spatial areas prone to natural disasters Volcanic eruptions, can be done with the mitigation measures related to spatial planning based on risk level.

Desa Pino Baru merupakan salah satu wilayah administratif di Kecamatan Air Nipis, Kabupaten Bengkulu Selatan, Provinsi Bengkulu. Studi ini berfokus memberikan informasi terkait kestabilan lahan di daerah Air Nipis dan sekitarnya yang didukung dengan fenomena geologi. Penelitian ini bertujuan untuk mengetahui keterkaitan antara struktur geologi dan implikasinya terhadap kestabilan lahan di daerah penelitian. Observasi lapangan didukung dengan analisa data struktur geologi untuk menginterpretasikan struktur daerah penelitian. Satuan batuan pada lokasi penelitian meliputi 2 formasi, yaitu: Formasi Seblat dan Formasi Lemau dengan struktur geologi berupa lipatan dan sesar. Analisis remote sensing berupa NDVI untuk menampilkan tingkat kerapatan vegetasi, kemudian analisa ruggedness index menunjukkan tingkat resiko tanah yang tidak stabil, dan analisa dissection index menunjukkan tingkat resiko pergerakan tanah di daerah penelitian. Berdasarkan analisis secara keseluruhan, dapat dihasilkan interpretasi bahwa daerah dengan tingkat kerentanan longsor di daerah penelitian paling tinggi berada pada arah WSW–ENE atau di Desa Batu Ampar, Desa Pino Baru, dan Desa Sukarami.

The study area that is mainly hilly, contains volcanics matters such as breccias, tufaceous lapili, tufand lava. Several outcrops are followed by mineralization where quartz vein also occurred.Developed structures in the study area are quite complex, where NE – SW faults pairing with NW –SE faults. Mineralization zones and quartz vein are found on faults segments, these evidence shows thatthere are primary Au prospect at the subsurface in the study area.

AbstractKarangsambung-Totogan Formation is the most exposed rock unit in Kalisana Village, Karangsambung, Kebumen. These two formations also form the bedrock of the study area, which consists of claystone. The Karangsambung-Totogan Formation is composed of sedimentary groups which are mixed up due to the gravity process known as Olistostrome. Pieces of centimeter to hundreds of meters of sedimentary rocks are scattered randomly during the scaly clay matrix. Kalisana Village is around 20 kilometers from the center of Kebumen Regency. Kalisana Village has an area of 349 hectares, with 109.86 hectares of rice fields and 239.14 hectares of dry land. Rice field area consists of irrigated and non-irrigated rice fields. Every year this research area often experiences water shortages during the dry season. The purpose of this study is to get a reference in making decisions to overcome the shortage of raw water in areas affected by drought through groundwater sources. The research methods include the preparation stage (literature study, previous research studies, preparation of tools, review of maps, etc.), field orientation, field work/measurements, data compilation, data analysis, evaluation and data processing. The results obtained three geological rock units namely; claystone associated with the Karangsambung Formation, a fragmented claystone unit associated with the Totogan Formation and breccias associated with the Waturanda Formation. Based on the geoelectric sonding results at three sounding locations, a subsurface image is obtained. At first sonding was found sandstones at depth of 11-18 meters with an aquifer thickness of about 7 meters. Correlation of tree geoelectric sonding location successfully described the subsurface of the Karangsambung-Totogan Formation which forms the base. The maximum geoelectric depth is around 120 meters. Keyword: Karangsambung Formation, Totogan Formation, Karangsambung, Geoelectric, aquifer AbstrakFormasi Karangsambung-Totogan merupakan satuan batuan yang paling banyak tersingkap di Desa Kalisana, Karangsambung, Kebumen. Dua formasi ini juga menjadi batuan alas di lokasi penelitian, yang terdiri dari batulempung. Formasi Karangsambung-Totogan tersusun oleh kelompok sedimen yang tercampur aduk karena proses pelongsoran gaya berat yang dikenal dengan istilah Olistostrome. Bongkah-bongkah batuan sedimen berukuran centimeter hingga ratusan meter tersebar secara acak dalam masadasar lempung hitam bersisik (scaly clay). Desa Kalisana berjarak sekitar 20 Kilometer dari pusat Kabupaten Kebumen. Desa Kalisana mempunyai luas 349 Ha, dengan luas lahan sawah 109,86 Ha dan lahan kering seluas 239,14 Ha. Luas lahan sawah terdiri dari sawah irigasi dan non-irigasi. Setiap tahun lokasi penelitian ini sering mengalami kekurangan air saat musim kemarau. Maksud penelitian ini adalah mendapatkan acuan dalam pengambilan keputusan untuk mengatasi kekurangan air baku pada daerah yang terdampak kekeringan melalui pencarian sumber airtanah. Metode penelitian meliputi tahap persiapan (studi pustaka, studi penelitian terdahulu, persiapan alat, penelaahan peta-peta, dan lain-lain), orientasi lapangan, pekerjaan lapangan/pengukuran, kompilasi data, analisis data, evaluasi dan pengolahan data. Hasil yang didapatkan berupa tiga satuan batuan geologi yaitu; batulempung yang berkorelasi dengan Formasi Karangsambung, satuan batulempung berfragmen yang berkorelasi dengan Formasi Totogan dan breksi yang termasuk Formasi Waturanda. Berdasarkan hasil geolistrik di tiga lokasi sounding didapatkan gambaran bawah permukaan. Di lokasi sonding 1 ditemukan lapisan batupasir pada kedalaman 11-18 meter dengan ketebalan akuifer sekitar 7 meter. Korelasi 3 titik sonding geolistrik berhasil menggambarkan bawah permukaan Formasi Karangsambung-Totogan yang menjadi alas tersebut. Kedalaman maksimal geolistrik sekitar 120 meter.Kata kunci: Formasi Karangsambung, Formasi Totogan, Karangsambung, Geolistrik, akuifer

Ciletuh located in Ciemas district, Sukabumi, West Java is known by its geological diversity (geodiversity). This area is located at the southwestern of Java Island and directly adjacent to the Indian Ocean. Ciletuh is a very attractive tourist visits area and deserve to be visited. This area is planned to be a National Geopark area and Global Geopark Network in 2016. This will certainly have an impact on the change of land use in the next few years. The change of land use will affect indirectly to the distribution of erosion rate in research area. The higher of land use changes, the higher of erosion rate that can cause environmental quality degradation. This research aims to reveal the land use changes can affect the level of of vulnerability to erosion in Ciletuh. This research method uses laboratory and studio analysis. Remote sensing analysis is used to delineate land use. The distribution rate of erosion in research area can be known through erosion calculation formula. Based on delineation of land use, Ciletuh have areas of land cover consisting of 6.666.104 m2 (9,7%) plantation, 10.444.567 m2 (15,2%) forests, 3.252.843 m2 (4,7%) settlements, 82.264 m2 (0,1%) swamps, 22.863.874 m2 (33,3%) paddy fields, 19.474.346 m2 (28,37%) bushes, 2.057.689 m2 (2,9%) vacant lands, and 3.788.699 m2 (5,5%) moors area. The result of early research identification indicates that the level of vulnerability to erosion associated with the greatest land cover is moor and vacant lands.

Research area generally have a big slope. Based on Van Zuidam classification (1983), the research area can be divided into 3 angle class or slope: 1) area which have surging hilly morphology with of slope range from 25 - 35 %, 2) area which have precipitous hilly morphology with slope range from 35 - 90 %, and 3) area which have hilly morphology cut sharply or hilly very precipitous with slope 90 – 150 %Area which including into landslide-zone in generally reside at area which have precipitous hilly and surging hilly morphology, there are at group 2 and 3. Both of the area of compiler rock generally not yet lihtificated powerfully, water content is high enough especially in rain season and rock generally relative soften

Sebagai negara dengan kekayaan panas bumi yang melimpah, sudah semestinya dapat memenuhi kebutuhan energi listrik lebih mudah. Salah satu indikator potensi panas bumi di sini yaitu keberadaan gunung api yang menerus dari barat hingga timur. Manifestasi panas bumi juga ditemui di daerah Sembalun, Lombok Timur. Sebagai bentuk dukungan mencapai target besar pemanfaatan panas bumi, dilakukan penelitian berupa identifikasi daerah potensial panas bumi dengan penginderaan jauh pada data citra landsat 8. Penelitian ini menggunakan parameter Normalized Difference Vegetation Index (NDVI), dan Land Surface Temperatur (LST) didukung peta topografi dari data DEM dan peta geologi. Setelah dilakukan mapping dan overlaying menggunakan software ArcGIS, diperoleh hasil levalisasi potensi panas bumi daerah Sembalun yang terbagi menjadi 4, yaitu daerah dengan potensi tinggi, sedang, rendah, dan sangat rendah, dengan kawasan utara Gunung Rinjani menjadi area yang cukup tinggi dilihat parameter yang ada.Kata Kunci: Panas bumi, NDVI, LST, Topografi, Litologi

There are closed spatial relationship between the different phases, the different metallic minerals, the precious-metals bearing minerals, the volcanic host rock and the plutonic intrusions of the Arinem vein system. Nine samples from Bantarhuni vein including four samples from quartz-sulfide vein from different stages and level, and five samples from altered host rock were analyzed geochemically by Induced Couple Plasma (ICP) and Induced Couple Plasma Mass Spectrometer (ICP-MS) to identified the geochemical characteristics of Bantarhuni vein system. The geochemical data obtained from the quartz-sulfide vein and altered host rock of the Bantarhuni vein is mostly similar to those obtained from Arinem vein samples. Some samples from the alteration zone have contents similar to the less altered Jampang Formation and andesitic Miocene and Pliocene intrusions rocks, with a little depletion and enrichment for some oxides. The abundance of ore and gangue minerals vary among each stage of mineralization of Bantarhuni vein. The REE in the Arinem and Bantarhuni veins considered to have been extracted by water/rock interaction between hydrothermal solution and country rocks. Some REE pattern of the mineralized Bantarhuni vein show irregularly pattern and this is could be due to high content of sulfide minerals in the samples, or due to analytical error during sample dissolution. The gold and silver contents in the Arinem and Bantarhuni veins vary very much and there is relatively low Au and Ag concentrations occur in samples from any alteration zone. There is no correlation found between gold and other major ore elements except for Ag. The highest content of Au is having low ΣREE.   Keywords : Bantarhuni vein, Geochemical, quartz-sulfide vein, water-rock interaction.                                            Terdapat hubungan spasial antara fase yang berbeda, mineral logam yang berbeda, mineral yang mengandung logam mulia, batuan induk (host rock) vulkanik dan intrusi plutonik dalam sistem urat Arinem. Sembilan sampel dari urat Bantarhuni yang terdiri dari empat sampel dari urat kuarsa-sulfida dari stages dan kedalaman yang berbeda, dan lima sampel dari host rock yang terubah dianalisis secara geokimia degan Induced Couple Plasma (ICP) dan Induced Couple Plasma Mass Spectrometer (ICP-MS) untuk mengidentifikasi karakteristik geokimia dari sistem urat Bantarhuni. Data analisis geokimia yang diperoleh dari urat kuarsa-sulfida dan batuan induk terubah dari urat Bantarhuni sebagian besar sama dengan yang diperoleh dari sampel urat Arinem. Beberapa sampel dari zona alterasi memiliki kandungan mirip dengan Formasi Jampang yang terubah lemah dan batuan intrusi andesit berumur Miosen dan Pliosen, dicirikan dengan sedikit pengurangan dan pengayaan untuk beberapa oksida. Kelimpahan bijih dan mineral gang bervariasi di dalam setiap tahap mineralisasi di urat Bantarhuni. REE di urat Arinem dan Bantarhuni kemungkinan diekstraksi dengan adanya interaksi air/batuan antara fluida hidrothermal dan batuan sampingnya. Beberapa pola REE dari urat Bantarhuni yang termineralisasi menunjukkan pola yang tidak teratur dan hal ini kemungkinan disebabkan oleh tingginya kandungan mineral sulfida dalam sampel, atau karena kesalahan pada saat analisis dalam pelarutan sampel. Kandungan emas dan perak dalam urat Arinem dan Bantarhuni sangat bervariasi dan konsentrasi Au dan Ag pada sampel dari setiap zona alterasi relatif rendah. Tidak ada korelasi ditemukan antara emas dan unsur bijih utama lainnya kecuali dengan Ag. Sampel dengan kandungan Au tertinggi adalah sampel yang memiliki ΣREE rendah. Kata kunci: Urat Bantarhuni, geokimia, urat kuarsa-sulfida, interaksi air-batuan.

This research was carried out at the southern pit wall in the open gold mining area of PT. Kelian Equatorial Mining, located at 00 00 '32, 56 "S - 00 05 '09, 14" South Latitude and 1150 23’ 29,02" - 1150 28' 04,73" East Longitude. Administratively, it located in the Tepu area, Subdistrict of Linggang Bigung, West Kutai, East Kalimantan province. Physiographically that area is a part of Central Kalimantan volcanic arc.Rocks exposed in this area can be divided into 4 (four) rock units, i.e. The Eocene Sandstone Unit; The Lower Miocene Andesitic Pluton Unit; The Middle Miocene Hydrothermal Breccia Unit; and The Early Miocene Diatreme Breccia Unit.Geological structures that developped in this area were joints and faults. The faults are dilational structures types, in the form of sinistral- and dextral normal faults. These geological structures facilitated the penetration of andesite, followed by the appearence of hydrothermal fluids which produced the formation of hydrothermal breccia, and diatreme breccia. Hydrothermal breccia fragment consisting of andesite and sandstone, usually in jigsaw textured which are arranged in a matrix rock flour (Sillitoe, 1985), i.e. very fine grained material that came from milling process of breccia fragments. The carbonate minerals in the form of bladed texture are dominat minerals that filled the interfragments and matrix cavities. Partially, apart of carbonate minerals, the bladed silica was also present in cavity filling. The cavity filling minerals are associated with the appearence of metallic minerals.The alteration zones in the research area can be grouped into three zones, namely: 1.) Zone containing chlorite + clay + sericite + adularia + carbonate 2.) Zone containing sericite + carbonate + clay + adularia ± quartz and 3.) Zone containing carbonate + clay + sericite + adularia + quartz / silica. These alterations are classified as subpropylitic - until phyllic zones (Corbett & Leach, 1996). Metal mineralization such as sphalerite, galena, pyrite, covellite, arsenopyrite and chalcopyrite are associated with carbonate alteration ± adularia ± quartz ± sericite ± clay were primarily formed as a cavity filling and veins in hydrothermal breccia. The analysis results of Au and Ag contents in some rocks samples of hydrothermal breccia ranged from 0.04 grams / ton to 8.96 grams / ton Ag and 0.55 to 11.8 grams / ton, while the recovery of Au ranged between 16.08% up to 85.12%. The highest content and % recovery value of Au was founded in hydrothermal breccia.The mineralization stages can be divided into three stages: 1). The pre-brecciation stage that associated with the occurence of chlorite, sericite, adularia, clay and pyrite dissemination as well as the formation of carbonate veinlets and quartzs in direction of the Northwest - Southeast, 2) The syn-brecciation stage, it related to the formation of hydrothermal breccia, i.e. the occurence of carbonate and silica enrichment and the alteration minerals such as sericite, adularia, clay that related to the deposition of base metals as cavity filling and as veinlets in the direction of Southwest-Northeast. 3) Post-breccia stage was related to the occurence of carbonate veinlets ± base metals which associated with the clay minerals. Those cut the fragments, rock flour matrix, cavities filling minerals in hydrothermal breccia after the their formation in the direction of Southwest-Northeast.Mineralization in the area of study occured as ore deposits in hydrothermal breccia and in the veins as well as the veinlets. Hydrothermal breccia formed by two processes, i.e.; structural control and high-pressure hydrothermal fluids, at the temperature more than 200° - 250° C, with the acidity condition of (pH) 6, 6-8, 3. This condition is classified as a system of low sulphidation that related to porphiry with gold-carbonate base metal deposits (Corbett & Leach, 1996).

Daerah Sepaku merupakan daerah potensi batu gunung, berupa batu gamping, batu pasir dan batu lempung, dengan morfologi bergelombang kuat dan sedang. Penelitian ini bertujuan untuk mengetahui jenis batuan penyusun struktur bawah permukaan berdasarkan nilai resistivitas batuan di sekitar. Penelitian dilakukan dengan menggunakan metode geolistrik Bawono (Modified: Naniura NRD 300 HRF) konfigurasi Schlumberger dengan mengukur nilai tahanan jenis lapisan tanah di daerah Sepaku sebanyak 10 lintasan. Pemodelan dan inversi data lapangan dilakukan menggunakan software Res2DinV. Hasil penelitian menunjukkan keberadaan batu gamping memiliki nilai tahanan jenis antara 300 – 1870 Ωm, batu pasir 30 – 300 Ωm, dan batu lempung 3 – 30 Ωm. Litologi batuan secara keseluruhan didominasi perselingan batu pasir dan lempung, sedangkan batu gamping hanya memiliki ketebalan 15 – 40 meter. Litologi batu gamping memiliki gua di Lintasan GL1, dan rongga atau rekahan di semua lintasan.

ABSTRAKSurvei Magnetotelurik (MT) telah dilakukan di daerah panas bumi Maranda yang terletak di Kabupaten Poso, Sulawesi Tengah. Pola struktur geologi di daerah Maranda didominasi oleh arah utara-selatan yang berasosiasi dengan arah sesar naik Poso yang berada di bagian baratnya dan pola struktur berarah relatif barat-timur sebagai antitetiknya. Hasil perhitungan dengan geotermometer silika baik pada kondisi conductive cooling maupun adiabatic cooling menunjukkan nilai yang hampir sama dimana suhu reservoir berdasarkan geotermometer kelompok mata air panas Maranda berkisar antara 125-184°C. Tujuan survei ini adalah untuk mengetahui struktur tahanan jenis bawah permukaan yang berkorelasi dengan sistem panas bumi. Pengukuran MT di daerah panas bumi Maranda telah dilakukan pada 42 titik ukur yang tersebar membentuk 8 buah lintasan berarah baratdaya-timurlaut dengan jarak antar titik ukur sekitar 1000 m. Peta tahanan jenis (MT) memperlihatkan adanya pola kelurusan berarah baratlaut-tenggara dengan sebaran tahanan jenis tinggi di sebelah baratdaya dan sebaran tahanan jenis rendah di sebelah timurlaut. Batuan penudung yang dicirikan dengan nilai tahanan jenis rendah berada di sebelah timurlaut di antara mata air panas Maranda dan mata air panas Kawende dengan pola yang membuka ke arah timurlaut. Batuan penudung ini diperkirakan berada di dekat permukaan hingga kedalaman 750 meter dengan ketebalan 500-750 meter. Kata kunci: magnetotelurik, panas bumi, Maranda, Sulawesi Tengah ABSTRACTMagnetotelluric (MT) surveys have been conducted in the Maranda geothermal area located in Poso District, Central Sulawesi. The geological structure pattern in the Maranda region is dominated by the north-south direction associated with the Poso thrust fault in the west and the structures pattern of relative east-west trending as their antithetes. The results of calculations with silica geotherm meter in both conductive cooling and adiabatic cooling conditions show almost the same value that the reservoir temperature based on the geothermometric of the Maranda hot springs ranges from 125-184 ° C. The purpose of this survey is to knowing the structure of the subsurface resistivity that correlates with the geothermal system. Measurements of MT in geothermal Maranda have been done on 42 scattered points forming 8 trajectory direction southwest-northeast with the distance between the measuring point about 1000 m. The type resistance maps (MTs) show an alignment pattern in northwest-southeast direction with high resistance range in the south-west and low-end resistance range to the northeast. The cap rocks that are characterized by low-end resistance values are northeast of Maranda's hot springs and Kawende's hot springs with a pattern that opens to the northeast. The cap rocks are estimated to be near the surface to a depth of 750 meters with a thickness of 500-750 meters. Keywords: magnetotelluric, geothermal, Maranda, Central Sulawesi

The West Java area is part of back arc basin comprising a number of North-South oriented half graben and sub-basin situated at the southernmost edge of the Sunda Platform. The area chosen for this study is called as Kuningan Area, located at the Bogor Trough, which has a complete sequence of rifting events. However, limited wells are available; therefore, a basin fill history could not be identified.It is predicted that this area has a hydrocarbon potential. Play concepts in the Northwest Java Basin, especially focused on syn-rift and post-rift sediments, whilst in the past they concentrated on carbonate build-ups on structural highs and the Jatibarang volcanics.In the offshore of NW Java Basin, to the north of this area, the proven oil and gas province are scattered in the several sub-basins such as Northwest Java Basin and Arjuna Basin. A number of different plays as shown in structural cross section in W-NE direction of the West Java Basin show the presence of extensive block faulting in the basement forming graben-like structures. The deposition of carbonate build-up is clearly indicated as Baturaja Formation in the lower part and Parigi Formation in the upper part. It is hoped that this configuration extends to the Kuningan Area which is mostly covered by thick Quaternary volcanic rocks.

Penelitian dilakukan di Cekungan Bandung bagian timur yang secara geologi tersusun oleh dominasi batuan vulkanik berumur Kuarter. Penelitian ini bertujuan untuk mengungkap hubungan antar aspek morfotektonik yang terdiri dari indeks gradien panjang sungai (SL) dan hipsometri (HI) dalam merespon aktivitas tektonik di daerah penelitian. Penelitian dilakukan menggunakan media citra DEM (Digital Elevation Model) melalui dukungan SIG (Sistem Informasi Geografis) di studio. Perangkat lunak ArcGIS 10.0 digunakan dalam proses pengolahan citra serta Microsoft Excel digunakan dalam proses perhitungan dan analisis data. Berdasarkan hasil penelitian, daerah penelitian terdiri dari enam DAS, yaitu DAS Citarik Hulu, Cijalupang, Ciwirama, Ciburial, Cikeruh, dan Cimande yang sebagian besar berada pada morfologi perbukitan dan gunung hingga pedataran dengan kemiringan lereng mulai dari sangat curam hingga datar. Daerah penelitian memiliki enam pola pengaliran sungai, yaitu pola radial, subradial, subdendritik, parallel, subparallel, dan anastomotik. Secara umum, keenam pola pengaliran tersebut menunjukkan bahwa daerah penelitian didominasi area berlereng curam hingga sangat curam dan tersusun oleh batuan vulkanik di bagian utara, timur, dan selatan, berlereng landai hingga datar dan tersusun oleh material lepasan di bagian tengah hingga barat, serta dipengaruhi struktur geologi minor. Hal ini dibuktikan dari hasil perhitungan nilai SL (113,24 – 409,75) dan HI (0,22 – 0,50) yang menunjukkan respon aktivitas tektonik rendah hingga cukup tinggi. Selain itu, korelasi nilai SL dan HI menunjukkan tingkat hubungan sangat kuat yang tercermin dari koefisien korelasi (r) = 0,932, yaitu semakin besar nilai SL maka semakin besar pula nilai HI.

Aliran air dari hulu ke hilir dipengaruhi oleh berbagai hal, terutama adalah jenis batuan penyusun di daerah resapan serta intensitas deformasinya. Kombinasi struktur sesar dan kekar dapat memodifikasi variasi permeabilitas dari sangat permeabel (akuifer bagus) sampai dengan sangat kedap (akuiklud). Tujuan penelitian ini yaitu untuk mengetahui kondisi geologi, baik kondisi geologi permukaan maupun bawah permukaan yang terdiri atas batuan penyusun, tatanan tektonik dan pola strukturnya serta pengaruhnya terhadap aliran airtanah. Secara administratif daerah penelitian meliputi daerah Kecamatan Gekbrong, Kabupaten Cianjur, Provinsi Jawa Barat.Daerah penelitian dibagi menjadi 3 satuan geomorfologi, yaitu Satuan Geomorfologi Tubuh Gunungapi Strato, Satuan Geomorfologi Kaki Gunungapi Strato dan Satuan Geomorfologi Perbukitan. Urutan satuan stratigrafinya, dari yang tua sampai yang muda, adalah Satuan Breksi Tuff, Satuan Breksi Vulkanik, Satuan Tuff Breksian, Satuan Lava Andesit dan Lava Basaltik. Batuan di daerah penyelidikan umumnya berasal dari endapan volkanik dan dapat dikelompokan berdasarkan kisaran nilai tahanan jenisnya. Sesar-sesar yang ada di permukaan adalah : Sesar Gekbrong, Sesar Cibeleng dan Sesar Cipadang, ketiganya berarah relatif baratdaya – timurlaut, sedangkan sesar di bawah permukaan berarah timurlaut – baratdaya tidak diberi nama. Daerah resapan dibatasi sesuai dengan batas sesar yang berarah timurlaut – baratdaya, mengindikasikan bahwa sesar ini bertindak sebagai sealing fault.Kata Kunci: Gekbrong, Endapan Vulkanik, Struktur Geologi, Daerah Resapan, Resistivitas

The purpose study to recognize and interprete resources of gold deposit in Long Agung, Malinau District, East Kalimantan Province. The field work also to interprete system of gold deposit in research area.

Nowaday natural resources have to be optimalized for humanitarian welfare, It needed manajemen of mining effort that have the same with characterization of each natural resourses, then it needed to take inventory of appearance of natural resources itself. All the information of mineral deposits be fitured in Map that covered in Identification and Mapping Potential Mineral Resourses Work.South Mountained Zone is a Table Land which developed a triangle with its top at southern Bandung have direction west to east, from The Pelabuhan Ratu Bay until Nusakambangan. Width of South Mountained Zone is about 50km. This zone is divided into 3 subzones, which is Jampang Subzone, Pangalengan Subzone, and Karangnunggal Subzone. The research area is included in Jampang subzone that contain Pra-tertiary Rock and Tertiary Sediment and appears in western of this zone. The Oldest rock found at South Mountained Block West Java consist igneous rock, ultrabase, and basalt (Van Bemmelen, 1949) and Skish which appears in Pra-tertiary age (Mark, 1957). Endang Toyib (1975) comment that complex melange deposits which is consist in Ciletuh area are the oldest rock (Mps, Mgg, Mgp). Those rocks formed by ofiolith and metamorphic rock and sedimentary rock consist black clay that scraped and mixed tectonically.