Ore Geology

Ore deposits are sources of raw materials for industries. This paper examines the types of ore deposits in Nigeria. Ores of iron, tin-niobium-tantalum deposits, and precious metals in the Nigerian basement complex are predominantly associated with the metasediments (gneisses and schists). Associated with the older granites and metavolcanics are ores of nickel, chromium. The processes of ore formation in Nigeria vary from metamorphism and metasomatism to sedimentation. Base metals (Lead and Zinc) and some uranium deposits accumulate in Nigerian sedimentary basins. Presented in this article is a table listing all ore deposits, their types, mode of occurrence, and locations in Nigeria.

This report documents several new findings concerning the geology and mineral potential of the central East Tintic Mountains, Utah. For example, fission-track ages and 40Ar/39Ar ages which we report suggest that some of the
volcanism and alteration in this area is as old as 37.4 to 35.3 Ma. This early episode of volcanism was contemporaneous with lacustrine deposition; the overlying volcanic rocks and cross-cutting intrusions range in age from about 34.5 to 33.6 Ma. This implies that a large caldera related to the eruption of the younger Packard Quartz Latite and Fernow Quartz Latite is not present in this area . However, our data suggest that a smaller caldera related to the eruption of the tuff member of the Copperopolis Latite may be present. We note that many monzonite dikes and intrusions in this area are hornblende bearing and are correlative in modal and chemical composition with the productive Silver City Stock rather than the barren Sunrise Peak Stock. The large areas of hydrothermal alteration which surround these intrusions
exhibit many similarities to the well-studied alteration halos in the East Tintic District. The age, composition, and field relationships of the post-lacustrine volcanic rocks suggest that they may represent, in part, the extrusive equivalents of the monzonite dikes and Silver City Stock. Our work suggests that the Silver City Stock and related intrusions may be part of one of the youngest (33.6 ± 0.2 Ma) igneous events in the central East Tintic Mountains, but not as young as previously suggested (ca. 31.5 Ma). In addition, our recent work has documented the existence of unusually large (and abundant) magmatic sulfides in lava vitrophyres and vent-facies biotite latite dikes, which are the surface expressions of the Silver City Quartz Monzonite intrusions in this area. In addition, preliminary analytical data suggest that the sulfides host most (-75%) of the Ag present in the latites. The East Tintic Mountains are potentially the first locality, worldwide, where Ag in mesothermal veins can be demonstrated to be derived from degassed Ag-bearing magmatic sulfides. Consequently, the central East Tintic
Mountains are a favorable area for exploration for Ag (Pb-Zn-Cu-Au) ore bodies because: 1) productive monzonite intrusions are present, and 2) Paleozoic rocks favorable for ore deposition may be present beneath relatively thin volcanic cover because the area is not entirely enclosed within a caldera.

Vymazalováite, Pd3Bi2S2 is a new platinum-group mineral discovered in the Komsomolsky mine of the Talnakh deposit, Noril’sk district, Russia. It forms small (from a few μm to 20–35 µm) inclusions or euhedral grains in intergrowths of polarite, sobolevskite, acanthite and unnamed (Pd,Ag)5BiS2 in aggregates (up to ~200 µm) in galena and rarely in chalcopyrite. It occurs with telargpalite, cooperite, braggite, vysotskite, sopcheite, stibiopalladinite, sobolevskite, moncheite, kotulskite, malyshevite, insizwaite, Au-bearing silver and the newly described mineral kravtsovite (PdAg2S) in association with pyrite, chalcopyrite and galena in vein-disseminated mineralization in skarn rocks. Synthetic vymazalováite is brittle; it has a metallic lustre and a grey streak. In plane-polarized reflected light, vymazalováite is creamy grey and appears slightly brownish against galena in the assemblage with chalcopyrite. It exhibits no internal reflections. Average reflectance values in air for natural and synthetic vymazalováite are (R natural, R synthetic in %) are: 46.35, 45.7 at 470 nm, 47.65, 47.45 at 546 nm, 48.5, 48.2 at 589 nm and 49.5, 49.0 at 650 nm. Seven electron probe micro-analyses of vymazalováite give an average composition: Pd 40.42, Bi 49.15, Ag 0.55, Pb 1.02, S 7.77 and Se 0.26, total 99.17 wt.%, corresponding to the empirical formula Pd3.05(Bi1.89Ag0.04Pb0.04)Σ1.97(S1.95Se0.03)Σ1.98 based on a total of 7 atoms per formula unit. The simplified formula is Pd3Bi2S2. The mineral is cubic, space group I213, with a = 8.3097(9) Å, V = 573.79(1) Å3 and Z = 4. The density calculated on the basis of the empirical formula and cell dimensions of synthetic vymazalováite is 9.25 g/cm3. The strongest lines in the powder X-ray diffraction pattern of synthetic vymazalováite [d in Å (I) (hkl)] are: 4.15(32)(200), 2.93(78)(220), 2.40(100)(220), 2.08(53)(400), 1.695(34)(422), 1.468(35)(440) and 1.252(31)(622). The structural identity of natural vymazalováite with synthetic Pd3Bi2S2 was confirmed by electron back-scatter diffraction measurements on the natural sample. This new mineral honours Dr Anna Vymazalová of the Czech Geological Survey, Prague.

Повышение результативности, качества, дешевизны, доступности и скорости выполнения геологоразведочных работ является актуальной задачей для развития и восполнения минерально-сырьевой базы Казахстана и мира в целом. Современный прогресс научных, компьютерных и программных решений, космических и авиационных технологий, открыли инновационные возможности в составлении Геологической отчётности и в методике проведения геологоразведочных работ на всех стадиях. Инновационные способы применения данных спутникового дистанционного зондирования земли и современных геоинформационных систем позволяют усовершенствовать методику составления Геологической отчётности и проектирования геологоразведочных работ с целью более качественного прогнозирования, поисков, разведки и эксплуатации пластово-инфильтрационных месторождения урана.

This study utilizes the trace and rare earth element geochemistry of bulk ores and in situ LA-ICP-MS analyses of
mineral grains to clarify the controversy in the origin of the Bahariya sedimentary iron ores, Egypt. Different types
of iron ores were identified in the Bahariya Oasis including high grade, high-Mn, high-Ba, oolitic, and ochreous
iron ores. Hematite and goethite are the main constituents of the studied ores with some manganese oxide
and hydroxide minerals (pyrolusite, bixbyite, cryptomelane, aurorite, romanechite, manjiroite, and pyrochroite).
Barite is common in the high-Ba ore, while some quartz, calcite, and halite are detected in the oolitic iron ore.
High-Mn iron ores are characterized by higher contents of SiO2,Al2O3, MgO, CaO, Na2O, and K2O, while highBa iron ore has higher TiO2contents. Analyses of bulk ores and in situ mineral grains are characterized by substantially high contents of Ba (average of 9497 ppm); also Zn and Sr occur in considerably high concentrations
(averages of 4263 and 429 ppm, respectively). Mn-rich ores and Mn-bearing minerals show relative enrichments
of trace metals compared to the Mn-poor ores probably due to the ability of Mn-bearing minerals tofixsuchtrace
metals by adsorption, absorption, and/or replacement. TheΣREE ranges between 2.6 and 80 ppm with an average
of 23 ppm. High-Mn ores show higherΣREE (average of 61 ppm) compared with the low Mn ore (average of
13 ppm). The oolitic iron ore shows very lowΣREE content (7 ppm). Red and yellow ochers from El Gedida
mine have similarΣREE values (38 and 39 ppm, respectively), while red ocher from the Ghorabi area has relatively higherΣREE (57 ppm). Chondrite-normalized REE patterns of all types of iron ores, whether in the form of bulk
ores or Fe- and Mn-bearing grains, have LREE enrichment relative to HREE as shown by (La/Yb)Nratios that vary
from 1.7 to 29.4. Majority of the bulk samples and mineral grains have negative Eu anomalies with EuN/Eu*
ranges from 0.68 to 0.8. However, bulk samples of one high grade and high-Ba ores as well as some of the Mnbearing grains from El Gedida ores show positive Eu anomalies with Eu/Eu* ranges from 1.1 to 17.7. With few exceptions, all bulk ores and mineral grains show negative Ce anomalies with Ce/Ce* range from 0.28 to 0.96. A
seawater precipitation (hydrogenous to hydrothermal exhalite) is proposed for the Bahariya iron ores. The hydrogenous origin is suggested based on the occurrence of high-Mn iron ores in the base of the iron ore succession,
oolitic texture of some of these ores, Si–Al plot, low La/Ce ratios, high Y/Ho ratios, and LREE-enriched patterns
with negative Eu anomalies of most of the bulk ores and mineral grains. The hydrothermal contribution to the
source of these iron ores can be evident from the high contents of some trace elements such as Ba, Zn, and Mo,
and plots the analyzed samples in the hydrothermalfields of the Fe–M–(Ni + Co + Cu)∗10 ternary diagram,
(Co + Ni)–(As + Cu + Mo + Pb + V + Zn) and (Co + Ni + Cu–Co/Zn) binary plot, lowΣREE concentrations
and positive Eu anomalies and high La/Ce ratios in some of the analyzed samples. The hydrothermal contribution
looks for local effect and is restricted to El Gedida area

Thick ferromanganese (Fe-Mn) crusts from four Cretaceous seamounts (The Paps, Tropic, Echo and Drago) at the southern Canary Island Seamount Province (CISP) in the northeastern tropical Atlantic were recovered along the flanks and summits from 1700 to 3000 m water depths. CISP is composed of N 100 seamounts and submarine hills, is likely the oldest hotspot track in the Atlantic Ocean, and is the most long-lived of known hotspots globally. The Fe-Mn crusts grow on basalt-sedimentary rock substrates below the northeastern tropical Atlantic core of the oxygen minimum zone (OMZ) with a maximum thickness of 250 mm at a water depth of 2400 m. The mineral-ogical and chemical composition of these Fe-Mn crusts indicate a hydrogenetic origin. The main Mn minerals are vernadite with minor interlayered todorokite and asbolane-buserite. Fe oxides are essentially ferroxyhyte and goethite. The Fe-Mn crusts show high average contents in Fe (23.5 wt%), Mn (16.1 wt%), and trace elements like Co (4700 μg/g), Ni (2800 μg/g), V (2400 μg/g) and Pb (1600 μg/g). Rare earth elements plus yttrium (REY) averages 2800 μg/g with high proportions of Ce (1600 μg/g). Total platinum group elements (PGEs) average 230 ng/g, with average Pt of 182 ng/g. Two main types of growth layers form the crusts: 1) a dense laminae of oxides with high contents in Mn, Co and Ni associated with vernadite and Cu, Ni, and Zn associated with todorokite; 2) botryoidal layers with high contents in Fe, Ti, V and REY associated with goethite. The Fe-Mn crusts from the CISP region show higher contents in Fe, V, Pb and REY but lower Mn, Co, Ni and PGEs contents than Pacific or Indian ocean seamount crusts. The oldest maximum age of initiation of crust growth was at 76 Ma (Cam-panian, Late Cretaceous). Using a combination of high resolution Co-chronometer and geochemical data along an Electron Probe Micro Analysis (EPMA) transect, four stages in morphology, chemical contents and growth rates can be differentiated in the the Cenozoic crusts since 28 Ma, which we interpret as due to changes in the ventilation of the North Atlantic OMZ and to the increase of Saharian dust inputs. An earliest growth period, characterized by similar contents of Fe and Mn in the interval 27.8–24.45 Ma (late Oligocene-early Miocene) reflects slow precipitation related to a thick OMZ. An intermediate laminated zone with higher contents of Fe, Si and P, high growth rates reaching 4.5 mm/Ma, and precipitation of Fe-Mn oxides during the interval 24.5–16 Ma is related to periods of ventilation of the OMZ by intrusion of deep upwelling currents. Significant increase in Fe contents at ca. 16 Ma correlates with the onset of incursions of Northern Component Waters into the North Atlantic. Finally, since 12 Ma, the very low growth rates (b0.5 mm/Ma) of the crust are related to a thick North Atlantic OMZ, an increase in Sahara dust input and a stable thermohaline circulation.

Projede Kurşun ve Çinko hazırlama teknikleri kullanılarak Türkiye’deki Çinko’nun katı ile sıvı ayrımının Kızıl Ötesi ışınımla ile yapılabilirliği açısından değerlendirme olanaklarının araştırılması hedeflenmiştir. Bu çalışmada endüstriyi yakından ilgilendiren çinko madeninin, katma değerli ürün kazanımı için geçtiği aşamalar hakkında ve kızılötesi ışınımla kurutucu tasarlanması hakkında ilgili bilgiler ele alınmıştır. Çinkonun hangi sanayilerde kullandığı, işletilmesi ve önemi açıklanmıştır. Kurutucu tipleri hakkında bilgi verilmiş ve kızılötesi ışınımla kurutucunun diğerlerinden avantajları ele alınmıştır. Çinko konsantresinin çıkarıldığı ve işlem gördüğü yerler ile alındığı yer ile ilgili bilgiler verilmiş ve uygulanması istenilen endüstriyel ölçekli kızılötesi ışınımla kurutucu ve deneysel ölçekte kızılötesi ışınımla kurutucu tasarımı yapılmıştır. Çinko cevheri gerekli uygun koşular sağlanarak kızılötesi ışınımla kurutularak bu sistemin fizibilite çalışması ortaya koyulmuştur. Tez kapsamında literatür çalışması olarak Türkiye ve Dünya’da çinko hakkında yapılan yayınlar derlenmiştir. Çalışmanın deneysel kısmında ise Türkiye’nin Balıkesir Balya bölgesinden alınan çinko numuneleri kullanılmıştır. Alınan numuneler üzerinde nem analizleri yapılmış ve tasarlan cihaz içinde kızıl ötesi ışınım ile muamele edilerek nem oranı saptanmıştır.Bu katı sıvı ayrımı sonucunda elde edilen bulgulara yer verilmiştir.Bu alanda yapılabilinecek çalışmalar için bir ön araştırma niteliği ortaya çıkarılmıştır.Bu çalışmanın yapılması sonucu edilecek kâr ortaya koyulmuştur.

Tunisa is the eastern segment of the Atlas mountains ranges formed during the Alpine orogeny. The Atlasic foreland is in the front of the Tellian folded belt Zinc and lead ores of Tunisan Atlassic foroland occur from Triassic to Upper Miocene dolostones and limestones. Four ore-deposits groups can be distinguished: (1a) Pb-Zn-Cu-As-Hg in the Tellian belt, (1b) Pb-Zn  in Upper Miocene strata in Upper Micene basins; 2) (a) Pb-Zn-Sr in Triassic cap-rocks and (b) Pb-Zn in the Upper Cretaceous cover of Triassic evaporates domes; 3)  (a) F-Ba-Pb-Zn in Jurassic platform carbonate and (b) Pb-Zn-Ba or siderite in Aptian platform carbonate; 4) F-Ba-Pb-Zn in Jurrasic platform carbonates. Replacement of limestones and open-space fillings in karst cavities are the principal types of ore occurrences; lesser amounts occur as open-space filling of fractures. Ore-forming brines have salinities in the range of 10 to 20 Wt% NaCl equ and temperature in the range of 70 to 200°C. Hydrocarbons as oil fluid inclusions or oil seeps are aundant in most the ore-deposits.  For the genesis of the ore-deposits we propose a orogenically-driven circulation of brines in crustal rocks, followed by the ascent and reaction with fluids in the overlaying rocks, as a consequence of the tectonic collisions of the European and African plates.

Reservoir-infiltration uranium deposits («sandstone» type) today are the main active source of
uranium mineral raw materials in the world and the only one in Kazakhstan. Their main advantage in the form of
better environmental friendliness, productivity and minimum production costs creates prospects for their further
detection in various parts of the world. It is important to simplify and improve multi-stage, expensive and difficult
geological exploration works for the purpose of forecasting and searching them with affordable innovative solutions.
The available multispectral satellite imagery has opened up new opportunities for the study of uranium ore
provinces. Mapping of uranium ore provinces based on multispectral satellite imagery allows them to be compared
with certain key ore-controlling data from geological and geophysical studies. The near-surface visible nature of
geotectonic structures, climatic conditions and zonal anomalies are more easily and efficiently visualized using
modern space technologies and computer solutions. The explanation of the derived correlations with the geotectonic
and climatic conditions allows the use of multispectral images in order to simplify and improve the quality of
forecasting, prospecting and exploration of reservoir-infiltration uranium deposits. More advanced aerial and space
remote sensing methods make it possible to detect surface anomalies associated with this type of ore. The scientific
explanation of the nature of these anomalies and their role in the geological and genetic model of ore formation
creates a solid theoretical basis for improving the exploration methodology. The convergence of the results obtained,
their theoretical explanation, simplicity and convincingness of the results make it possible to make new predictions
of promising areas of reservoir-infiltration uranium regions for several of the key ore-controlling factors and use this
methodology in conjunction with other data from regional and local studies at all stages of exploration

Gold, a precious native metal, exists as occurrences in the Nigerian schist belts. This work was a term paper reviewing the works of authors on the ore geology, lithologic, and structural mode of formation of the platinum group element in Nigeria.  It is common to find gold in the form of veins, stringers, lenses, and reefs in the regional N-S shear zone (in the Northwestern part of Nigeria). Generally, gold closely associates with quartzofeldspathic and sulphidic minerals (quartz and pyrite, respectively). Most of the gold deposits accumulate in the Maru, Anka, Kushaka, Zuru, Egbe-Isanlu, and Ilesha supracrustal zones.

Banded Iron Formations (BIFs), as the name suggests, are chemically precipitated sedimentary rocks having alternating Fe-rich and Si-rich bands. The origin of BIF has always remained a debated topic of research. The BIF in the Badampahar Greenstone Belt is of Mesoarchean age that formed a part of the East Indian Shield. Here, the BIF is interlayered with metavolcanic rocks, quartzite, phyllite, and chert, which indicates a typical greenstone sequence. The present paper focuses a little on the depositional setting of the BIF and mostly on the post-depositional processes, which include formation of iron ores. Geochemical and sedimentological evidences suggest insignificant detrital input in the genesis of BIF and significant chemical precipitation in the deposition. The post-depositional processes involved subsequent stages of deformation, metamorphism, hydrothermal, and supergene processes after deposition. Hydrothermal fluid is found enriched in High Field Strength Elements (HFSEs) and transition elements. This hydrothermal fluid altered the BIF to form titanomagnetite and ilmenite-rich rock in Jashipur. Recycling of BIF magnetite into hematite and removal of silica also attributed to hydrothermal alteration, which ultimately led to form iron ores.

Un estudio reciente de la mina de bolivianita Anahi revela que la mineralización es  el producto de fluidos termales intracratonicos  que migraron a lo largo de un lineamiento  profundo en el borde de una cuenca con relleno de sedimentos clásticos del Proterozoico Superior.  La mineralización esta hospedada en caliza Cambriana y  relacionada a una estructura de hundimiento. Se presenta como cemento de brechas de colapso en cavernas de disolución, relleno de fisuras y grietas que se abrieron por procesos cársticos y la circulación de fluidos termales. El cuarzo cristalizó a base de la mezcla de fluidos termales enriquecidos en sílice con aguas descendentes meteóricas de baja temperatura cerca de la paleo-superficie. La geometría de los cuerpos mineralizados esta  controlada por la morfología subterránea del paleo-carst. La sílice precipitó cerca y encima del paleo-acuífero originalmente como ópalo-calcedonia con poco pirita.  Las gemas de cuarzo cristalizaron debajo de esta capa de sinter. La edad de la mineralización es desconocida. Pero el proceso cárstico comenzó  seguramente después de la consolidación de la caliza durante una fase continental con clima húmedo y esta efectivo hasta el presente. La migración de los fluidos termales fue probablemente  incitado por  el evento ígneo-térmico  que tuvo lugar en el Cretácico Superior producíendo extrusiones alcalinas en el oriente Boliviano.

Bolivia tiene todavía un excelente potencial geológico minero a desarrollar a pesar de una larga
tradición en la extracción minera. Pero por falta de seguridad jurídica y paz social no se efectuaron en los
últimos diez años las inversiones necesarias para descubrir nuevos yacimientos. El Precámbrico del
Oriente Boliviano es la región con mayor potencial también para algunos tipos de yacimientos no
tomados en cuenta hasta la fecha. La aplicación de modelos mejorados de yacimientos, el uso de
métodos geofísicos y geoquímicos modernos y de sistemas avanzados de información geográfica
podría ayudar en la identificación de nuevos yacimientos.

This book describes the history of mineral exploration and discovery in Indonesia over the past 25 years (1993-2017). During this period ('Period II') porphyry copper-gold, high- to low-sulfidation epithermal gold-silver, nickel laterite, and bauxite were the main deposit types targeted. Several other styles of mineralisation were found ,including sediment-hosted gold, orogenic gold, SEDX and MVT zinc-lead, and polymetallic VHMS.  Exploration took place in four stages: Phase II-1 (1993-1999) witnessed the biggest exploration boom in the country'e history, fueled largely by higher metal prices, the Grasberg and Batu Hijau discoveries, and the Busang fraud; Phase II-2 (2000-2005) was a time of limited exploration activity due to adverse politico-economic events, and Busang having been exposed as the largest hoax in world mining history; Phase II-3 (2006-2013), which coincided with the super commodity cycle, focused exclusively on brownfield exploration with nickel laterite and bauxite topping the list; Phase II-4 (2014-2017) represented another bust, mirroring a worldwide downturn in exploration activity, exacerbated by the implementation of unfavourable legislation.
Following a summary of the regional and metallogenic setting of Indonesia, case histories are presented for 58 moderate, large- and giant-size deposits discovered in Period II, describing how they were discovered and subsequently explored. A background geological summary and resource estimates are provided for each deposit. Some regional exploration programmes are also discussed, as are case histories of the Ertsberg Mineral District (spanning 80 years) and five deposits that have been explored for more than 30 years and are close to development. The Period II case histories are  then analysed together with those documented previously for the preceding 25 years (Period I; van Leeuwen, 1994) in terms of discovery and exploration methods, discovery frequency and costs, and time needed from exploration initiation to discovery, and from there to production. The two periods are compared and key success factors identified. The final part of the report looks both back (lessons learnt from 50 years of exploration) and forward (how to reverse the sharply downward discovery trend that started around six years ago

Istilah mesotermal merupakan klasifikasi endapan menurut Lindgren (1933) yang mengacu pada pembentukan endapan bijih yang terbentuk pada kedalaman 1.5 – 3 km dengan temperature berkisar 200°C - 300°C. Lindgren menggunakan istilah mesotermal untuk endapan emas dengan host rock berupa batuan metamorf. Di masa kini, endapan emas diklasifikasikan menjadi dua kelompok: Orogenic Gold Deposits dan Reduced Intrusion-related Gold Deposits. Endapan emas orogenik (orogenic gold deposits) merupakan endapan emas ‘mesotermal’ yang banyak ditemukan dan dieksploitasi saat ini. Orogenic Gold Deposits terkait dengan deformasi, metamorfisme dan magmatisme selama proses orogenesis pada batas kontinen dalam skala litosfer. Oleh karena itu, tatanan tektonik endapan ini berada di zona orogen sabuk metamorfik greenstone. Endapan emas orogenik dapat menunjukkan beberapa tipe mineralisasi baik itu berkaitan dengan zona ductile, brittle-ductile, atau zona brittle. Fluida bermigrasi sepanjang zona rekahan yang dipicu oleh peristiwa penurunan tekanan (pressure drop) selama peristiwa seismik. Bijih terbentuk sebagai pengisi urat pada sesar orde kedua dan ketiga di sepanjang perubahan jurus pada zona sesar. Mineralisasi bervariasi dari stockwork dan breksia di zona brittle, menjadi laminated crack-seal veins dan sigmoidal veins di zona brittle-ductile, dan menjadi tipe diseminasi dan penggantian di zona ductile. Umumnya endapan ini memiliki hostrock batuan fasies sekishijau dengan fluida hidrotermal yang terdiri dari unsur H2O-CO2-H2S, bersalinitas rendah hingga moderate dengan pH mendekati netral. Mineral yang sangat umum hadir pada endapan ini adalah mineral karbonat, sulfida, kuarsa dan mineral zona kloritisasi-propilitisasi. Mineral sulfida yang hadir berupa pirit, pirhotit, arsenopirit dengan jumlah ≤3-5%, mineral karbonat seperti ankerit, dolomit dan kalsit hadir melimpah sebanyak ≤5-15% setelah kuarsa. Di samping itu, kadar emas pada endapan ini berkisar antara 5-30 g/ton. Pada tahun 2008, ditemukan emas letakan yang berasosiasi dengan urat kuarsa terdeformasi dalam batuan metamorf di daerah Langkowala (Bombana), Sulawesi Tenggara, yang diduga sebagai endapan emas orogenik di Indonesia.

Lazarus Ercker: Beschreibung: Allerfürnemisten Mineralischen Ertzt, vnnd Berckwercksarten: wie dieselbigen, vnnd eine jede in sonderheit, jrer natur vnd eigenschafft nach, auff alle Metaln Probirt, vnd im kleinem fewer sollen versucht werden, mit erklerung etlicher fürnehmen nützlichen Schmelzwerckem im grossen fewer, auch schaidung Goldt, Silber, vnnd andere Metalln ... vnd was denen allen anhengig in fünff Bücher verfast, Dergleichen zuuorn niemals in Druck kommen ... mit schönen Figuren vn[d] abriß der Instrument, trewlich vn[d] fleissig an Tag geben. Prag 1574

Framboids, spherical aggregates of minute, usually pyrite, grains are the commonest texture of sulfides in sedimentary rocks. They also occur in many other environments, ranging from magmatic rocks to antiquarian books. Framboidal textures are formed by several minerals including copper and zinc sulfides, greigite, magnetite, magnesioferrite or hematite, as the products of both primary deposition and replacement. Special attention is paid to pyrite framboids in this paper, with detailed descriptions of different framboid-related forms: annular framboids, sunflower framboids, micro- and polyframboids. Framboidal forms are often hierarchically structured over three size scales, with complexities ranging from microframboids, to framboids, and to polyframboids. Pyrite in framboids results from inorganic reactions between dissolved iron and sulfide, with a greigite intermediary. The sulfur is usually biogenic in origin. Simple pyrite framboids are formed during aggregation, possibly enhanced by the magnetic properties of the monosulfide precursor. Further processes, including particulation and organically controlled aggregation, result in more complicated forms such as polyframboids. Pyrite framboids can grow to euhedral grains provided the supply of iron and sulfide is not limited. Pyrite framboids often occur in close spatial relationship with organic matter, silica or carbonates, which influence their formation and growth. Replacement of iron sulfide framboid-related forms by other minerals can be indicative of sediment diagenetic conditions, or additional processes such as mineralization in ore deposits. Framboids influence the distribution of many trace elements. Due to their high specific surface areas, framboids can accumulate these trace elements during growth. Recrystallization of framboids can redistribute many trace elements. An overview of the common association between pyrite framboids and fossils is given, stressing both the importance of organic matter in framboid formation, and of the framboids in the processes of mineralization and preservation of fossils. Iron sulfide framboids may have influenced the earliest stages of life formation on the Earth as a source of energy and catalytic action, by accumulating organic compounds, and by acting as reaction chambers and templates which facilitated reproduction and information transfer. Applications from framboid studies are presented, ranging from determination of the redox conditions in water and sediment columns using size and distribution of framboids, to evaluation of deterioration processes in museum specimens.

Food is essential for human survival. Phosphate rock, a critical mineral for the production of fertilisers, is key to achieving food security globally. This article reviews the mineralogy, geological nature, processing and economics of this important resource. Apatite is the primary mineral of phosphate rock. Phosphate rock occurs geologically as sedimentary phosphorites, guano, and igneous deposits. Phosphate rocks are beneficiated by flotation. Morocco (Western Sahara, inclusive) and China rank amongst the highest producers of phosphate rock. Africa holds over 80 percent of world's phosphate rock reserves. As at the year 2016, the price of marketable phosphate rock was USD 72 per metric tonne.

In mining operations carried out below the water table, mine area could potentially affect the surrounding. With further deepening of the mine and quarry, the drawdown can impact on water supply wells and base flow. The variation in radius of influence under confined and unconfined aquifer condition is assessed using a hypothetical case study with three operational quarry sites. Average pit-wise radius of influence (R0) for the pit mine, under unconfined and confined aquifer conditions is 963 m and 61 km, respectively, whereas effective radius (Re) for total (cumulative) excavated mine area is 1.7 and 146 km, respectively. It means that the maximum and minimum value of overall impact/influence for the unconfined aquifer lies in-between 963 m and 1.7 km. Similarly that the maximum and minimum value of overall impact/influence for the confined aquifer lies in-between 61 and 146 km. Meanwhile, Re or effective radius for total (cumulative) excavated area seems more appropriate from evaluation viewpoint due to the overlapping (superposition) concentric mining quarries. Thus, assessment of quarry-wise and total radius of influence is of importance to fulfil targeted production, economically with minimum interruptions as part of the mine planning. Moreover, it helps us to assess, monitor and regulate the impact of a mine-dewatering program in the area. Also, the pumping test is often used to estimate radius of influence; it can trigger the inflow or radius of influence. Estimate of the radius of influence using analytical equation mainly independent of discharge/abstraction from the aquifer stands as a preferred choice for the prediction of radius of influence at the quarry/mine pit. There is a strong rationale that policies should be informed by such analytical assessment because it helps us to prevent or minimize negative impacts as part of regulation and pit-mining management and are useful tools for practitioners to design economically efficient and cost-effective in situ groundwater remediation systems, to contain contaminant plumes, to evaluate the surface–subsurface water interaction and to verify numerical models.

Geologi ialah ilmu pengetahuan yang mempelajari material bumi secara menyeluruh, dan juga menyelidiki lapisan lapisan batuan yang ada di dalam kerak bumi. Geologi mempelajari asal mula, struktur, penyusun kerak bumi, berbagai macam proses yang sedang berlangsung maupun setelah pembentukannya, sampai dengan keadaan bumi saat ini. Di dalam kerak bumi terdapat bermacam – macam batuan dan diantara lapisan – lapisan kerak bumi terdapat air yang kita gunakan sehari – hari. Geologi juga mempelajari sejarah – sejarah perkembangan bumi beserta makhluk yang pernah ada dan hidup di bumi ini. Adapun pengertian geologi menurut para ahli:

Lenses of radioactive Quartz Pebble Conglomerates (QPC) and associated quartzites are exposed along western margin of Archean Bonai Granite in Singhbhum-Orissa Craton, eastern India intermittently spreading over a strike length of 8–10 km. QPCs are radioactive while quartzites are mostly non-radioactive in nature. The purpose of the research is to investigate and characterize the radioactive QPC and quartzites geochemically to decipher their paleo-weathering conditions, provenance characteristics and possible tectonic setting of deposition. Geochemical data suggest moderate to high chemical weathering conditions in the provenance areas of QPC and quartzites. Major, trace and REE data indicate predominantly felsic to partly mafic-ultramafic sources for the deposition of radioactive Quartz Pebble Conglomerates from the surrounding Archean terrain. Elevated values of Th, U, Pb, La, Ce, Y and low Sc with high critical trace elemental ratios of Th/Sc, La/Sc, Th/Cr and Zr/Sc in radioactive QPC indicate their derivation from felsic igneous source. Low concentration of Th and Sc in quartzites compared to QPC and their variable Th/Sc ratios indicate both felsic and mafic sources for quartzites, albeit their preferential felsic affiliation. Higher Cr/Th ratios in quartzites (18.4), moderate Cr/Th in QPC (5.42), low to moderate Y/Ni in QPC (0.36–12.4) and quartzite (0.29–1.88), along with Au ranging from 30 to 1527 ppb, Pt up to 188 ppb and 682 ppb in QPC and quartzites respectively point towards some contribution from mafic-ultramafic source as well. REE patterns and in particular negative Eu anomalies for both QPC and quartzites further support their derivation from felsic rocks and could possibly linked to some of the phases of Archean Singhbhum Granite and Bonai Granite. Granitic to pegmatitic source for QPC is also revealed by the presence of rounded to sub-rounded mon-azite, zircon and thorian-uraninite grains in their matrix. Study indicates that QPC and quartzites were deposited in a passive margin tectonic setting developed during Archean between a span of 3.3 and 3.16 Ga along the western margin of Bonai Granite when the reducing condition was prevalent as indicated by their low Th/U ratios (<4.0) and presence of detrital grains of uraninite and pyrite in QPC. Radioactive QPC from western margin of Archean Singhbhum-Orissa Craton bears broad resemblance with QPC from Witwatersrand basin of South Africa and Elliot Lake, Canada and thus appears to be ideal sites for exploring QPC hosted U (+Au-PGE) mineralization in the analogous areas.