 | | Journal (article/letter/editorial) | | altered braunite-kutnahorite lutite at the Smartt Mine in the Kalahari manganese field, South Africa. Geological... with fibre lengths up to 10cm, occur at Smartt mine in the Kalahari manganese field. The occurrence...minerals as finely intergrown aggregates of cryptomelane and montmorillonite. Later Van Biljon (referred...(Waychunas, 1991). This group includes also cryptomelane (K-rich), coronadite (Pb-rich), romanechite...occurrence of manjiroite and todorokite at Smartt Mine in detail and to develop a model for their origin |  | | Journal (issue) | | calcite; crystal aggregates 15 cm in size. Vеrklinii Mine, Dabugorsk, Pпmorskii Krai, Russia. Specimen: V...cassiterite (?), corundum, cristobalite, cuprite (x1), hematite (xl), iozite (wustite), maghemite, melanophlogite...bimessite, buserite, columbite (?), chromite, cryptomelane, gahnite,hercynite, hollandite, hibonite, ilmenite...pyrolusite composition are common. The author found cryptomelane represented by rosette intergrowths of reddishbrown...concentric-zonal oolites with a hematite—vernadite— rancieite—cryptomelane composition, which are up to |  | | Book (edition) | | hand specimens. Left: Internal reflections of hematite (red), azurite (blue), and malachite (green)....matrix is pyrrhotite. Left (bottom): Polysynthetic hematite twinning under XPL, red internal reflections are...different internal reflections. Left: Zonal growth of hematite. Dehydration Cracks Various colloform minerals...secondary minerals. Left: Coffinite (darker grey) with hematite (lighter grey) in dehydration cracks. 7 Light...stable, leading to an exsolution process (e.g., hematite, rutile, and ulvöspinel separating from ilmenite) |  | Dekoninck, Augustin, Monié, Patrick, Blockmans, Sabine, Hatert, Frédéric, Rochez, Gaëtan, Yans, Johan (2019) Genesis and 40Ar/39Ar dating of K-Mn oxides from the Stavelot Massif (Ardenne, Belgium): Insights into Oligocene to Pliocene weathering periods in Western Europe. Ore Geology Reviews, 115. 103191 doi:10.1016/j.oregeorev.2019.103191 | Journal (article/letter/editorial) | | andalusite, hematite) into secondary Mn oxides,—hydroxides and—oxyhydroxides (cryptomelane, nsutite, lithiophorite...the weathering fluids, while the formation of cryptomelane and then lithiophorite in veins is associated...transition metals (As, Co, Cu, Ni). Dating of pure cryptomelane samples corroborate the multistage character...romanechite cryptomelane cryptomelane cryptomelane hollandite Romanèche mine Romanèche mine Romanèche...Romanèche mine Romanèche mine Transinnes quarry Fernie mine and Buderus quarry Fernie mine and Buderus quarry |  | | Journal (article/letter/editorial) | | geochronology on late-diagenetic to early metamorphic cryptomelane from the Urucum sequence reveals a minimum depositional...yield reproducible plateau ages of 513 ± 3 Ma. Cryptomelane ages are interpreted to record the minimum timing...succeeded metamorphism. A chemically distinct cryptomelane generation identified in surface samples yield...Ar/39 Ar systematics implies that the oldest cryptomelane samples experienced Ar-loss probably via thermally...Research 228 (2013) 48–62 Fig. 2. (A) The Urucum district, located in the state of Mato Grosso do Sul at |  | | Book | | times, and there is evidence of at least one flint mine dating from this period. Finely worked and polished...derives its name from the saltmining district of Hallstatt in Upper Austria, where many prehistoric finds have...needles or fibres radiate from a common center (hematite or reniform limonite, Pls. 13, p. 73, and 21 ...occasionally workable veins of cassiterite with hematite (Mexico); many other minerals too form as sublimates... and deposited later. Some of the sedimentary hematite and pyrite deposits are formed in this manner: |  | | Journal (article/letter/editorial) | | (MnO2: 55-72%) and low-grade (MnO2:40-55%) from four mine profiles, Purnapani, Joda West, Khandbandh and Bamebariwere...ore samples, the higher is the grade. The iron (hematite and goethite), aluminium silicate (kaolinite)...which Mn ore mineralisation is observed along the mine profile. Small- to medium-grained cherty rocks are...from the mine, these are stacked gradewise on the basis of their physical appearance by mine workers....and discussion Three bulk Mn ore samples from four mine profiles, Joda West, Khandbandh, Purnapani and Bamebari |  | | Journal (article/letter/editorial) | | ultimately in the uppermostparts, by psilomelane,cryptomelane,pyrolusite,corohaditc, etc. (mainly Mn4+) in...carbonates(rhodochrosite), or higher oxides (pyrolusite, cryptomelane,manganite, psilomelaneetc.), the lowtemperaturesilicates...assemblage. The most stablephasesare pyrolusiteand cryptomelane,but manganite,nsutite and birnessitemay alsoform...PYROLUSITE -- Mn02 RAMSDELLITE -- MnO2 CRYPTOMELANE -- K Mn8016(RICHMOND & FLEISCHER, 194E) PSILOMELANE...(Hewett and Fleischer,1960). In other deposits, by cryptomelane, holMexico, rhodochrosite and mangansiderite |  | | Journal (article/letter/editorial) | | andconcretionary cryptomelane oresarefound.The oresconsistmainlyof micro-to cryptocrystalline cryptomelane associated...Layeredbraunitcoresmined are composed of braunitc,cryptomelane, pyrolusite,hematite,andquartz.The averageMn contentsof...oresrangefrom 25.63 percentin the detritus-rich cryptomelane oresto 49.51 percentin theconcretionary ones...LIPPOLT Prairie and brushwoods Lake Town Road Rail Mine FIG. 1. Geographic mapof the Urucumdistrict. yet...the ores,whichmight Fe, Mn DEPOSITS, URUCUM DISTRICT, BRAZIL 1377 havebeenrelatedto volcanicprocesses |  | | Journal (article/letter/editorial) | | BODIES AT CHIKLA, SITASONGI AND BUZURG, BHANDARA DISTRICT, MAHARASHTRA, FANINDRA NATH MANGA- DONGRI INDIA...north-eastof Karli and east of the Dongri Buzurg mine. In generalthe beddeddepositsstrike NE-SW in extremeeasternpart...Fro. 3. Botryoidalmanganeseore at Dongri Buzurg mine. Fro. 4. Permeationof manganese and silica throughjoint...manganite, pyrolusite, cryptomelene, coronadite, hematite and goethite. Except coronadite,all the above...colloidallow-temperatureores, manganite, pyrolusite,cryptomelane,coronaditeand goethitewere identified; but in |  | | Journal (article/letter/editorial) | | separated iron from 30 manganese to produce cryptomelane microbialites, which agglutinated to form manganese...initially transformed the manganese oxides into cryptomelane and 36 then into hollandite. 2 37 KEY WORDS...environment 39 1. INTRODUCTION 40 The Urucum mining district occupies an area of approximately 800 km2 and...Urban et al. (1992) estimated that the Urucum district 47 contains more than 600 Mt of rock with high...environment, for the carbonate BIFs of the Santa Cruz Mine region 63 located on the southeastern part of |  | | Journal (article/letter/editorial) | | Belnhausen, Darmstadt, Germany, ankerite, 138. Benallt mine, Caernarvon~hire, Wales, bannisterite and ganophyllite...studies of natural fabrics. I. Growth-fabrics in hematite kidneyore and in fibrous calcite, 70. BRAITHWAITE...dehydration, 791 ; and see riebeckite. Crystal growth in hematite, 625. 1193 I)AS(~Ut'TA (I). R.), Thermal deconq}osition...and boulangerite in the Rajpura belt, Udaipur district, Rajasthan, India, 1174. DAs GUeTA (S. P.), Paragenesis...138. Dongri Buzurg, Maharashtra, India, cryptomelane, vredenburgite, 1034. Donsa, Rhodesia, yttrotantalite |  | | Journal (article/letter/editorial) | | SILICEOUS MANGANESE FORMATIONS FROM THE URUCUM DISTRICT, MATO GROSSO DO SUL, BRAZIL CORNELIS KLEIN† Department...Na-containing manganese assemblages of the Urucum district, Mato Grosso do Sul, Brazil. It is based on ten...(weathering), both of which are pervasive in the Urucum district. The six BIF samples are representative of the...complex silicate assemblages with braunite, cryptomelane, some pyrolusite, and authigenic aegirine. The...distinctive because it consists almost entirely of hematite and chert (jasper) with almost all of the iron |  | | Journal (issue) | | Arthur Roe Famous Mineral Localities: The Brumado District, Bahia, Brazil..................................on the Benitoite Gem mine, it was stated that the Mina Numero Uno, a nearby mine having a similar mineralogy...famous Swiss “Cavradischlucht” (Cavradi Gorge) hematite crystals from the St. Gothard area. The crystals...crystal blades on the sur faces of the hematite. The hematite crys tals were mostly single and multiple...un usually thick ones caught my eye. Here the hematite crystals were perfectly terminated, particularly |  | | Journal (article/letter/editorial) | | rocks surrounding them, hollandire, micaceous hematite,cryptomelaneand pyrolusiteare presentassociatedwith...other is located6 milesto the west,passing Jhabua District,MadhyaPradesh, syngenetic bands throughAmliamal...discussion 1176 Location of Kajlidongri, Jhabua District, Madhya Pradesh and its regional geological setting...bands of quartz. It is commonlyaccompanied by hematite in the chloritezone,which apparentlyindicatesthat...brauniteare associated with 1179 hollandite,cryptomelane and pyrolusite. Some of xenoblasticgrainsof |  | | Journal (article/letter/editorial) | | braunite, hematite, and quartz are the dominant constituents, with minor pyrolusite, cryptomelane, and chalcedony...including well-rounded detrital quartz grains and hematite-chert pellets, as well as oncoids. The oncoids...ore deposits, like those of the Nikopol-Chiatura district in Ukraine and Georgia (Bolton and Frakes, 1985)...and underground room and pillar operations. The mine finally closed down in 1995, mainly because of high...e A 1153 B Major basement fault Opencast Mn Mine Basal conglomerate unit B A West f East f |  | | Report (volume) | | Argentian Cryptomelane and Bromargyrite in Volcanic Rocks near Silver Cliff, Colorado GEOLOGICAL SURVEY...J* I »c- > HI I t 1 ' f I Argentian Cryptomelane and Bromargyrite in Volcanic Rocks near Silver...silver minerals, especially a new variety of cryptomelane, and explains why unmined silver ores remain...remain at the surface in this old mining district UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON :.............................................. Cryptomelane ........................................... |  | | Journal (article/letter/editorial) | | 164 R O C K S AND M I N E R A L S Figure 1: Hematite incrustation pseudomorph after barite; 3 inches...pseudomorphs after pyrite, pyrite, siderite Faber lead mine—near Faber cerussite, chalcopyrite, fluorite, argentiferous...ilmenite, magnesite, magnetite, talc Stony Point mine—near Charlottesville chalcopyrite, cuprite, goethite...near Jordan mines barite, hematite (botryoidal and stalactitic), hematite incrusta tion pseudomorphs...County Enterprise mines (manganese)—near Beckham cryptomelane (gem quality), manganite, quartz crystals State |  | | Journal (article/letter/editorial) | | iron ores, including: (1) inclusions within the hematite and goethite and/or Mn accumulated on their active...cement-like Mn oxide and hydroxide minerals (bixbyite, cryptomelane, aurorite, romanechite, manjiroite, and pyrochroite)...the formation of Mn and Fe ores in the Urucum District, Brazil via a supergene process. Corona-Esquivel...million metric tons and are produced from El Gedida mine as raw material for the Egyptian Steel Company (ESC)...be addressed in this section. The El Gedida iron mine area is an oval shaped depression up to 15 km 2 |  | | Journal (article/letter/editorial) | | ' A l t a F o r m a t i o n ) of thinly banded hematite and jasper, with beds of manganese oxide. Lenticular...between ferruginous arkose and the typical banded hematite. It has been proved further, that in the western...interruption in the deposition of the dominating hematite-jaspilite, and the corresponding increase of the...The main constituent of the manganese ore is cryptomelane. This was proved Fig. 2. Arcosic sandstone... Chert and hematite form an ooid-like texture. Besides there are two granules of hematite (white), grains |  | | Journal (article/letter/editorial) | | Samples were also collected from deep boreholes and mine profiles. 2. Geological Setting RESOURCE GEOLOGY...view of Orahari deposit showing mine benches. B: An enlarged view of mine profile, note the extent of lateritisation...silicate/gangue minerals. The chief Fephases are hematite and goethite with kaolinite/ illite as the major...The major manganese minerals are romanechite/cryptomelane with occasional pyro- vol. 56, no. 1, 2006...Romanechite/ Cryptomelane, Pyrolusite, Pyrolusite, Cryptomelane, Lithiophorite, Quartz, Cryptomelane, Kaolinite/Illite |  | | Journal (article/letter/editorial) | | profile from the Serra da Moeda (MO) to the Sapecado mine (SAP) at the Serra do Itabirito. iron-formations...itabirites with deeply weathered itabirites and soft-hematite ores. Spier et al. (2003) provide detailed characterization...The major geological units present at the Sapecado mine are itabirites and iron ores of the Cauê Formation...out continu- ously along the eastern edge of the mine and show a very consistent sub-vertical dip and... The main banded iron formation at the Sapecado mine is a siliceous itabirite, the protore of the iron |  | | Journal (article/letter/editorial) | | Reivilo Formation (Fig. 4). Aluminous shales or hematite pebble conglomerates of the Gamagara Formation...diaspore and kaolinite with variable amounts of hematite and minor amounts of illite, anatase and rutile...structures such as intercalations of shale or hematite pebble conglomerate, often showing contorted sedimentary...partridgeite* bixbyite manganite roman6chite cryptomelane manganomelane** lithiophorite pyrolusite ramsdellite...distinguished in this group namely manjiroite (Na-rich), cryptomelane (Krich), coronadite (Pb-rich) and roman~chite |  | | Journal (issue) | | limonite pseudomorphs after pyrite, siderite Faber lead mine-near Faber cerussite, chalcopyrite, fluorite, argentiferous...topaz, tourmaline, triplite Trueheart pegmatite mine (f)-near Amelia beryl (var. aquamarine), microcline... magnesite, magnetite, pyrite, talc Stony Point mine-near Charlottesville chalcopyrite, cuprite, goethite...goethite, malachite, siderite Buck Mountain mine-near Forks of Buffalo arsenopyrite, fluroite, gold, scorodite...perrierite, rhabdophane, zircon Christian tract mine (copper)-near Sweet Briar actinolite-tremolite, |  | | Journal (article/letter/editorial) | | magnetite, maghemite, ferritchromite, goethite, hematite, kaolinite and gibbsite. Lithiophorite is the...Co grades 2.3– 4.5 times higher than the run-of-mine ore. Keywords Asbolane . Lithiophorite . Nkamouna...the main commodity as well as the first commercial mine in Cameroon. Similar to other oxide laterite deposits...Nkamouna and other mineralized laterites in Lomié district (modified from Lambiv Dzemua et al. 2009) spatial...yellowish brown matrix. Note the presence of deep red hematite selvedges associated with the bands. d Ferralite |
|
