Identifikasi Keterdapatan Mineral Radioaktif pada Urat-Urat Magnetit di Daerah Ella Ilir, Melawi, Kalimantan Barat

ABSTRAKElla Ilir secara administratif terletak di Kabupaten Melawi, Kalimantan Barat. Geologi regional daerah Ella Ilir tersusun atas batuan malihan berumur Trias–Karbon yang diterobos oleh batuan granitik berumur Yura dan Kapur. Keterdapatan mineral radioaktif di daerah tersebut terindikasi dari radioaktivitas urat-urat magnetit pada batuan malihan berumur Trias–Karbon dengan kisaran nilai 1.000 c/s hingga 15.000 c/s. Tujuan dari penelitian ini adalah menentukan jenis cebakan mineral bijih dan mengidentifikasi keterdapatan mineral radioaktif pada urat-urat bijih magnetit di daerah Ella Ilir. Metode yang digunakan adalah pemetaan geologi, pengukuran radioaktivitas, analisis kadar uranium, dan analisis mineragrafi beberapa sampel urat bijih magnetit. Litologi daerah penelitian tersusun oleh kuarsit biotit, metatuf, metabatulanau, metapelit, granit biotit, dan riolit. Sesar sinistral barat-timur dan sesar dekstral utara-selatan merupakan struktur sesar yang berkembang di daerah ini. Komposisi mineral urat-urat magnetit terdiri dari mineral-mineral bijih besi, sulfida, dan radioaktif. Mineral bijih besi terdiri dari magnetit, hematit, dan gutit. Mineral sulfida terdiri dari pirit, pirhotit, dan molibdenit sedangkan mineral radioaktif terdiri dari uraninit dan gumit. Keterdapatan urat-urat bijih magnetit dikontrol oleh litologi dan struktur geologi. Urat-urat magnetit pada metabatulanau berukuran tebal (1,5–5 m), mengisi rekahan-rekahan yang terdapat di sekitar zona sesar. Sementara itu, urat-urat magnetit pada metapelit berukuran tipis (milimetrik–sentimetrik), mengisi rekahan-rekahan yang sejajar dengan bidang sekistositas. Cebakan mineral bijih di daerah penelitian adalah cebakan bijih besi atau cebakan bijih magnetit berbentuk urat karena proses hidrotermal magmatik.ABSTRACTElla Ilir administratively located in Melawi Regency, West Kalimantan. Regional geology of Ella Ilir area is composed of metamorphic rocks in Triassic–Carboniferous age which are intruded by Jurassic and Cretaceous granitic rocks. Radioactive minerals occurences in the area are indicated by magnetite veins radioactivities on Triassic to Carboniferous metamorphic rocks whose values range from 1,000 c/s to 15,000 c/s. Goal of the study is to determine the type of ore mineral deposits and to identify the presence of radioactive mineral in magnetite veins in Ella Ilir area. The methods used are geological mapping, radioactivity measurements, analysis on uranium grades, and mineragraphy analysis of severe magnetite veins samples. Lithologies of the study area are composed by biotite quartzite, metatuff, metasilt, metapellite, biotite granite, and ryolite. The east-west sinistral fault and the north-south dextral fault are the developed fault structures in this area. Mineral composition of magnetite veins are consists of iron ore, sulfide, and radioactive minerals. Iron ore mineral consists of magnetite, hematit, and goetite. Sulfide minerals consist of pyrite, pirhotite, and molybdenite, while radioactive minerals consist of uraninite and gummite. The occurences of magnetite veins are controlled by lithology and geological structures. The magnetite veins in metasilt are thick (1.5–5 m), filled the fractures in the fault zone. Meanwhile, the magnetite veins in metapellite are thinner (milimetric–centimetric), filled the fractures that are parallel to the schistocity. The ore deposits in the study area are iron ore deposits or magnetite ore deposits formed by magmatic hydrothermal processes.

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PENYELIDIKAN GEOMAGNET BIJIH BESI DI WILAYAH JORONG KOTA BIRAH, KECAMATAN SUNGAI PAGU KABUPATEN SOLOK SELATAN

Jurnal Teknologi Informasi dan Pendidikan ◽

10.24036/tip.v10i3.21 ◽

2017 ◽

Vol 10 (3) ◽

pp. 64-72

Author(s):

Ceni Febi Kurnia Sari ◽

Yoszi Mingsi Anaperta

Keyword(s):

Magnetic Anomaly ◽

Iron Ore ◽

Intensity Variation ◽

Geological Structure ◽

Ore Deposits ◽

The North ◽

Side Rock ◽

Geological Conditions ◽

Iron Ore Deposits ◽

North Part

The measureable magnetic field intensity variation is then interpreted in the form of the distribution of the magnetic material below the surface, then used as the basis for the prediction of possible geological conditions observed. The iron ore deposits in the survei area are generally interpreted as a form of sediment that fills the rock cavities, especially in limestone cavities. This occurs due to the geological structure that gives space for the placement of mineralization of ore deposits in the side rock zone. The value of this magnetic anomaly is located in the west, the eastern, and also in the north part. Keywords: Geomagnet Method, Iron Ore, Magnetic Properties, Magnetic Value, Magnetic Anomaly Value.

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Geologi dan Identifikasi Cebakan Bijih di Daerah Batubesi, Belitung Timur

EKSPLORIUM ◽

10.17146/eksplorium.2017.38.1.3376 ◽

2017 ◽

Vol 38 (1) ◽

pp. 7

Author(s):

Ngadenin Ngadenin ◽

Frederikus Dian Indrastomo ◽

Adhika Junara Karunianto ◽

Ersina Rakhma

Keyword(s):

Iron Ore ◽

Southeast Asian ◽

Ore Deposits ◽

Geological Mapping ◽

The Other ◽

Geological Structures ◽

Ore Deposit ◽

Geological Setting ◽

Iron Ore Deposits ◽

Potential Area

ABSTRAKWilayah Batubesi di Belitung Timur berada di zona bagian timur dari granit jalur timah Asia Tenggara sehingga diduga merupakan daerah yang sangat potensial bagi terbentuknya cebakan bijih seperti besi dan timah bersama dengan monasit dan mineral asesoris lainnya. Penelitian ini bertujuan untuk mengetahui tataan geologi dan mengidentifikasi keterdapatan cebakan bijih dan mineral ikutan radioaktif di daerah Batubesi. Metodologi dalam penelitian ini adalah pemetaan geologi, pengukuran kadar uranium dan thorium, analisis petrografi, mineragrafi, dan butir. Daerah penelitian tersusun atas satuan granit dan metabatupasir. Granit diidentifikasi sebagai granit biotit dan granit hornblenda. Struktur geologi yang berkembang adalah sesar sinistral berarah barat daya – timur laut dan sesar dekstral berarah tenggara – barat laut. Cebakan bijih yang terbentuk di merupakan cebakan bijih besi primer tipe skarn iron tin polymetallic dengan magnetit sebagai mineral utama dan monasit serta zirkon sebagai mineral ikutan radioaktif . Mineral ikutan lainya adalah hematit, ilmenit, kasiterit, dan rutil. ABSTRACTThe Batubesi area in Belitung Timur is located in the eastern part of the Southeast Asian granites tin belt zone, so that it expected as a potential area for the occurence of ore deposit such as iron and cassiterite associate with monazite and other accessories minerals. The study aimed to understand the geological setting and to determine the occurrence of primary ore deposit and its radioactive accessories minerals. The methodologies in this research are geological mapping, uranium and thorium grade measurement, petrography, mineragraphy and grain counting analysis. The area composed by granite and metasandstone units. Types of granites are biotite and hornblende granites. The geological structures founded in this area are SW-NE sinistral and NW-SE dextral faults. Ore deposit in the area is primary iron ore deposits of skarn iron tin polymetallic type where magnetite is the main mineral while monazite and zircon are radioactive accessories minerals. The other accessories minerals are hematite, ilmenite, cassiterite, and rutile.

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On the Occurrence of considerable deposits of Limonite (Bog Iron Ore) in North-west Ross-shire

Mineralogical Magazine and Journal of the Mineralogical Society ◽

10.1180/minmag.1886.007.33.09 ◽

1886 ◽

Vol 7 (33) ◽

pp. 72-73

Author(s):

W. Ivison Macadam

Keyword(s):

Iron Ore ◽

Ore Deposits ◽

Present Communication ◽

North West ◽

The North ◽

Iron Ore Deposits

During the course of an inquiry into the nature and extent of the less known iron ore deposits of Scotland undertaken in connection with a paper to be communicated to the Society of Antiquaries of Scotland during the Winter Session 1886-87, I have been led to consieler certain masses of Bog Iron Ore which are distributed somewhat widely over the less cultivated portions of the country. The present communication deals only with the north-westerly portion of Ross-shire, and most of the localities are within the parish of Gairloch.

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INDEX AND PROBABILITY MAPS OF OCCURRENCE OF IRON ORE DEPOSITS: A PROPOSED GEOPHYSICAL APPROACH DEVELOPED IN CURRAL NOVO DO PIAUÍ (PI) STATE – BRAZIL

Brazilian Journal of Geophysics ◽

10.22564/rbgf.v31i3.311 ◽

2013 ◽

Vol 31 (3) ◽

pp. 365

Author(s):

Enos Nobuo Sato ◽

Teodoro Isnard Ribeiro De Almeida ◽

Vilson Marques Dias ◽

Jorge Kazuo Yamamoto ◽

Francisco De Assis Cavallaro ◽

...

Keyword(s):

Iron Ore ◽

Target Selection ◽

Ore Deposits ◽

Geological Mapping ◽

Iron Formation ◽

Probability Of Occurrence ◽

Iron Ore Deposits ◽

Exploration Area ◽

Host Rocks ◽

Iron Formations

ABSTRACT. This article shows the results of the development of a procedure called TC-ASA index which is based on the contrast of magnetic and radiometric properties between host rocks and the mineralization, being interpreted as the probability of occurrence and deﬁning ambience where iron formation to occur. It consists in subtracting the values of total count (TC) from the analytic signal (ASA), which are products of gammaspectrometry and magnetic methods, respectively. This index was applied to the actual data referring to the iron formations of Curral Novo do Piau´ı, where the main mineral is magnetite, thus characterized by high magnetic susceptibility and often associated with metabasic rocks. These rocks often present low concentration of radioactive elements, enabling the identiﬁcation of geological environment with potential for occurrence of iron ore. The use of this procedure allowed for the reduction of the exploration area, providing a fast target selection for geological mapping, geochemistry and ground geophysics. In addition, it supplies with important elements that will assist mining companies in setting strategic priorities.Keywords: iron ore exploration, probability of occurrence maps, gammaspectrometry, magnetometry. RESUMO. Este trabalho mostra os resultados do desenvolvimento de um procedimento aqui denominado Índice TC-ASA que tem por base o contraste de propriedades magnéticas e radiométricas entre as rochas encaixantes e a mineralização, sendo interpretado como probabilidade de ocorrência e delimitando ambiências propícias a ocorrências de formações ferríferas. Tal procedimento consiste na subtração dos valores de contagem total (CT) dos valores do sinal analítico (ASA), que são produtos dos métodos geofísicos gamaespectrométrico e magnetométrico, respectivamente. Este índice foi aplicado a dados reais coletados nas formações ferríferas de Curral Novo do Piauí, cujo principal mineral é a magnetita, caracterizada pela suscetibilidade alta e frequentemente associada à metabásicas. Estas rochas normalmente têm baixa concentração de elementos radioativos, possibilitando a identiﬁcação de ambiências geológicas potenciais para ocorrencia deste tipo de minério. A utilização deste procedimento permitiu a diminuição da área de pesquisa em estudo de reconaissance proporcionando uma rápida seleção de alvos para mapeamento geológico, geoquímica e geofísica terrestre. Além disto, proporciona elementos importantes que auxiliam as empresas de exploração mineral na deﬁnição de suas prioridades estratégicas.Palavras-chave: prospecção de minério de ferro, mapas de probabilidade de ocorrência, gamaespectrometria, magnetometria.

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Reconstruction and appraisal of Akunu–Akoko area iron ore deposits using geological and magnetic approaches

Materials and Geoenvironment ◽

10.1515/rmzmag-2016-0003 ◽

2016 ◽

Vol 63 (1) ◽

pp. 19-38

Author(s):

Cyril Okpoli ◽

Adedibu Akingboye

Keyword(s):

Structural Control ◽

Iron Ore ◽

Ore Deposits ◽

Geological Mapping ◽

Southwestern Nigeria ◽

Linear Feature ◽

Subsurface Geology ◽

Magnetic Methods ◽

Iron Ore Deposits ◽

High Magnetic Susceptibility

AbstractGeological mapping and magnetic methods were applied for the exploration of iron ore deposits in the Akunu–Akoko area of Southwestern Nigeria for the purpose of evaluating their geological characteristics and resource potentials. A proton magnetometer measures the vertical, horizontal and total magnetic intensities in gammas. The subsurface geology was interpreted qualitatively and quantitatively. The downward continuations and second vertical derivatives, the small-sized mineralised bodies and shallow features in the study area were mapped. The faults are trending in the following directions: NE–SW, NW–SE, N–S and E–W groups, while the iron ore mineralisation is structurally controlled by two major groups of fault trends, namely, the NE–SW and NW–SE; the N–S and E–W groups are mere occurrences that do not contribute to the structural control of the iron ore mineralisation in Akunu.The upward continuation has a linear feature similar to the principal orientation of the regional faults, while Locations 2 and 3 have relatively high magnetic susceptibility zones; suspected to be iron ore deposits. The depths to the magnetic sources ranged from 25 m to about 250 m.

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