“Garnierite” in weathering crust of ultramafic blocks from Cao Bang area, north Viet Nam

"Garnierite" is an important group of ore minerals in the supergene nickel deposits. Garnierite group minerals are Ni-bearing hydrous magnesium silicate formed due to the lateritic weathering of ultramafic rocks under humid tropical conditions. In the weathering crust on ultra-mafic blocks Ha Tri and Phan Thanh (Cao Bang province), garnierite group minerals have been found in the saprolite zone or as a coating on the surface of the fissures. Analytical results show that garnierite consists of a mixture of three solid solutions: (i) serpentine-like - 7Ao (lizardite-nepouite), (ii) talc-like - 10 Ao (pimelite-willemseite) and (iii) chlorite-like - 14 Ao (clinochlore-minite). EPMA analysis shows that garnierite in Cao Bang area is characterized by high Ni content (25.50-40.06%), low Fe content (0.09-0.9%) and almost no Al (<0.02%), similar to garnierite in the famous nickel mines in New Caledonia, Dominican Republic, etc... Notable, Ni and Mg contents in garnierite show a clear negative correlation, indicating the replacement for each other in the phases. Under the scanning electron microscope (SEM), garnierite has a raspberry shape forming continuous zones covering the unfinished weathered rock surface. These zones represent different stages of garnierite formation. The results of the study allow proposing a model of garnierite formation in the lateritic weathering zone in ultramafic blocks in the Cao Bang area.

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TYPOCHEMISTRY AND MINERAL ASSOCIATIONS OF NATIVE GOLD OF WEATHERING CRUST OF YEGORIEVSKIY ORE-PLACER AREA NORTH-WESTERN SALAIR)

GEOLOGY AND MINERAL RESOURCES OF SIBERIA ◽

10.20403/2078-0575-2020-2-96-109 ◽

2020 ◽

pp. 96-109

Author(s):

V. V. Kolpakov ◽

◽

P. A. Nevolko ◽

P. A. Fominykh ◽

◽

...

Keyword(s):

Native Gold ◽

Weathering Crust ◽

Mineral Associations ◽

Area North ◽

North Western

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ORE MINERALOGY AND MINERAL CHEMISTRY OF PYRITE, GALENA, AND SPHALERITE AT SORIPESA PROSPECT AREA, SUMBAWA ISLAND, INDONESIA

Journal of Applied Geology ◽

10.22146/jag.7191 ◽

2015 ◽

Vol 4 (1) ◽

Author(s):

Win Kant ◽

I Wayan Warmada ◽

Arifudin Idrus ◽

Lucas Donny Setijadji ◽

Koichiro Watanabe

Keyword(s):

Low Temperature ◽

Hydrothermal Fluid ◽

Mineral Chemistry ◽

Careful Study ◽

Average Content ◽

Thin Sections ◽

Content Ratio ◽

Fe Content ◽

Ore Minerals ◽

Ore Mineralogy

The Soripesa prospect area is located at Maria village, Wawo district, Bima region in the East Sumbawa Island, Indonesia. Lithology is dominantly composed of a lithic-crystal tuff of andesitic and dacitic composition and bedded limestone. The polymetallic epithermal quartz veins are hosted by andesitic volcaniclastic rocks. Within these veins, multiphases, colloform-crustiform, bedding to massive textures with pyrite, sphalerite, galena, chalcopyrite, chalcocite, azurite, and malachite are observed. Selected samples were analyzed by using ore microscopy and SEM-EDX. Ore minerals show replacement, ex-solution, colloform, and zonal textures. The paragenesis diagram was made from a careful study of polished sections and thin sections. Textures of ore minerals such as banded, exsolution, replacement, and zone, have been interpreted to correspond to the order of deposition. In pyrite, the average content of Co (0.45 wt.%) is higher than Ni content (0.14 wt.%) and it means that their origin may be hydrothermal origin. Average content ratio, Co:Ni is 2.81. Galena shows a low Ag content of 0.07 %in average. But they show a high Au content of 1.48 %in average. Sphalerite shows a low Fe content of 1.04 %in average and occasionally chalcopyrite inclusion/disease also occurred. Ga and Ge contents are also high in sphalerite. Co>Ni in pyrite, low content of Ag in Galena, low content of Fe and mole % FeS in sphalerite, high content of Ga and Ge, and log (Ga/Ge) in sphalerite, show that pyrite, galena, and sphalerite from Soripesa prospect area were formed under low temperature condition of hydrothermal fluid. Keywords: Ore textures, paragenesis, deposition, hydrothermal fluid, low temperature

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Mineralogická charakteristika hydrotermální mineralizace ze starých těžebních pozůstatků v oblasti Mladoňov - Nový Malín (silezikum)

Bulletin Mineralogie Petrologie ◽

10.46861/bmp.28.261 ◽

2020 ◽

Vol 28 (2) ◽

pp. 261-275

Author(s):

Zdeněk Dolníček ◽

Miroslav Nepejchal ◽

Vlastimil Flášar ◽

Jana Ulmanová

Keyword(s):

Electron Microprobe ◽

Bohemian Massif ◽

Native Gold ◽

Native Copper ◽

Ore Minerals ◽

Ore Mineralization ◽

Area North ◽

Native Bismuth

In the area north of Mladoňov, which is built by phyllites and quartzites of the Vrbno Group and granite-derived phyllonites of the Desná Group (Silesicum, northern part of the Bohemian Massif), there were found two types of hydrothermal ore mineralization in vein material sampled from remnants of old mining/prospection. The Cu(-Bi-Au) mineralization hosted by quartz gangue was found at the locality Husarčina šachta. A main ore mineral is chalcopyrite, which contains inclusions of pyrite, native bismuth, bismuthinite, a phase close to bismite, and native gold with fineness of 717 - 818. Baryte, recorded in part of collected samples, probably represents a significantly younger hypogene mineralization. Supergene minerals include malachite, azurite, a phase close to chrysocolla, bornite, Cu-sulphides, tenorite, native copper, limonite and probably also cuprite. A quartz-pyrite-pyrrhotite mineralization with accessory arsenopyrite and xenotime-(Y) and supergene limonite and baryte was recorded at localities Husarčina šachta and Kopka. Sporadically, Fe-sulphides contain elevated contents of Au (measurable by means of an electron microprobe), probably due to submicroscopic inclusions of native gold. Gold could be leached from wall rocks by ore fluids and/or remobilized from older mineralization to the younger one. The presence of traces of Cr, Co and Ni in some ore minerals implies for wider circulation of parent fluids involving probably also basic or ultrabasic rocks.

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Ore Microscopy of the Pegmatites of Keffi Area, North Central Nigeria

European Journal of Environment and Earth Sciences ◽

10.24018/ejgeo.2021.2.5.174 ◽

2021 ◽

Vol 2 (5) ◽

pp. 34-40

Author(s):

I. Y. Tanko ◽

K. Dzigbodi-Adjimah

Keyword(s):

Quantitative Analysis ◽

Light Microscopy ◽

Elemental Composition ◽

North Central ◽

Wavelength Dispersive Spectrometry ◽

Reflected Light ◽

Ore Minerals ◽

Backscattered Electron ◽

High Concentrations ◽

Area North

Investigation of the pegmatites of Keffi area was carried out in reflected light microscopy to determine the texture, elemental composition, and the semi-quantitative analysis of the ore minerals from the three groups of pegmatites identified in Keffi area: the non-mineralised, the intermediate and the mineralised pegmatites. Backscattered Electron (BSE) images and Wavelength Dispersive Spectrometry (WDS) were used. Petrographically the portion which is characterised by profuse albitisation, sericitisation and silicification is also associated with the development of cleavelandite, lepidolite, coloured tourmaline and high concentrations of cassiterite and columbite-tantalite (coltan).The order of crystallisation in the pegmatites is from microcline to quartz followed by (plagioclases) oligoclase to albite and by mica (from biotite to muscovite) then by accessory minerals such as black tourmaline, garnet, beryl and lastly oxides of Sn-Nb-Ta. Sphene, rutile, zircon, apatite, ilmenite, and magnetite appeared to be earliest minerals whilst garnet pyrite and chalcopyrite may be syn-metamorphic. Beryl and coloured tourmaline appear to be of hydrothermal phase.

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A TEM INVESTIGATION OF NICKEL ORE MINERALS FROM NEW CALEDONIA: NEW IMPLICATIONS FOR TECTONICS, HEALTH, AND ENVIRONMENTAL SAFETY

10.1130/abs/2016am-283867 ◽

2016 ◽

Author(s):

Brittany A. Cymes ◽

◽

Mark P.S. Krekeler ◽

Kirsten N. Nicholson ◽

Jeffry D. Grigsby

Keyword(s):

New Caledonia ◽

Environmental Safety ◽

Ore Minerals

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The Nickel Deposits of New Caledonia

Atlas of Economic Mineral Deposits ◽

10.1007/978-94-011-6511-2_5 ◽

1979 ◽

pp. 18-19

Author(s):

Colin J. Dixon

Keyword(s):

New Caledonia ◽

Nickel Deposits

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Passive obduction and gravity-driven emplacement of large ophiolitic sheets: The New Caledonia ophiolite (SW Pacific) as a case study?

BSGF - Earth Sciences Bulletin ◽

10.2113/gssgfbull.184.6.545 ◽

2013 ◽

Vol 184 (6) ◽

pp. 545-556 ◽

Cited By ~ 30

Author(s):

Yves Lagabrielle ◽

Alain Chauvet ◽

Marc Ulrich ◽

Stéphane Guillot

Keyword(s):

New Caledonia ◽

Oceanic Lithosphere ◽

Accretionary Wedge ◽

Plate Convergence ◽

Tectonic Force ◽

Sw Pacific ◽

Tropical Conditions ◽

Significant Extension ◽

Gravity Driven ◽

Basaltic Layer

Abstract The 300 km long allochthonous sheet of oceanic mantle forming the New Caledonia ophiolite displays three specific characters: 1) the ophiolite pile lacks concordant sheeted dykes and pillow basalt layers; 2) the ophiolite, refered to as the Peridotite nappe, is thrusted over the basaltic formations of the Poya terrane which are classicaly thought to originate from a different oceanic environment; 3) The basal contact of the ultramafic sheet is remarkably flat all along New-Caledonia and the Peridotite nappe has not been thickened during obduction, rather it experienced significant extension. This suggests that the peridotites have not been emplaced by a tectonic force applied to the rear. New petrological and geochemical results obtained from mantle rocks finally show that the Poya terrane may originate from the same oceanic basin as the peridotites. In this article, we consider such possible cogenetic links and we propose a simple model for the obduction of the New Caledonia ophiolite in which the Poya basalts represent the original cover of the Peridotite nappe. We infer that continuous uplift of the subducted units buried beneath the oceanic lithosphere in the northern part of New Caledonia drove passive uplift of the ophiolite and led to erosion and to initiation of sliding of the basaltic layer. During the Priabonian (latest Eocene), products of the erosion of the basaltic layer were deposited together with sediments derived from the Norfolk passive oceanic margin. These sediments are involved as tectonic slices into an accretionary wedge formed in response to plate convergence. The volcaniclastic sedimentation ends up with the emplacement of large slided blocks of basalts and rafted mafic units that progressively filled up the basin. Obduction process ended with the gravity sliding of the oceanic mantle sheet, previously scalped from its mafic cover. This process is contemporaneous with the exhumation of the HP-LT units of Pouebo and Diahot. Gravity sliding was facilitated by the occurrence of a continuous serpentine sole resulting from metasomatic hydratation of mantle rocks, which developed during the uplift of the Norfolk basement and overlying Diahot and Pouébo units. Progressive emersion of the obducted lithosphere allowed subsequent weathering under subaerial, tropical conditions.

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La genese et l'evolution des gisements de nickel de la Nouvelle-Caledonie

BSGF - Earth Sciences Bulletin ◽

10.2113/gssgfbull.s5-xvii.1-3.105 ◽

1947 ◽

Vol S5-XVII (1-3) ◽

pp. 105-160 ◽

Cited By ~ 6

Author(s):

E. de Chetelat

Keyword(s):

New Caledonia ◽

Parent Rock ◽

Minor Role ◽

Genetic Process ◽

Ore Minerals ◽

Nickel Ores ◽

Magnesium Silicates ◽

A Minor

Abstract The nickel ores of New Caledonia are the product of concentration of hydrous nickel and magnesium silicates during laterization of peridotite. The ore minerals are primary magmatic constituents of the parent rock, which is considered to have been intruded in the Tertiary. Serpentinization of the peridotite plays only a minor role in the genetic process; impermeable serpentinized zones acted as a barrier to the further migration of nickel-bearing solutions and thus aided concentration.

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Analysis of electroless nickel thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100086854 ◽

1991 ◽

Vol 49 ◽

pp. 510-511 ◽

Cited By ~ 1

Author(s):

C. W. Price ◽

E. F. Lindsey

Keyword(s):

Thin Films ◽

Inertial Confinement Fusion ◽

Electroless Nickel ◽

Inertial Confinement ◽

Plating Bath ◽

X Ray ◽

Nickel Thin Films ◽

Nickel Deposits ◽

Confinement Fusion ◽

Thickness Measurements

Thickness measurements of thin films are performed by both energy-dispersive x-ray spectroscopy (EDS) and x-ray fluorescence (XRF). XRF can measure thicker films than EDS, and XRF measurements also have somewhat greater precision than EDS measurements. However, small components with curved or irregular shapes that are used for various applications in the the Inertial Confinement Fusion program at LLNL present geometrical problems that are not conducive to XRF analyses but may have only a minimal effect on EDS analyses. This work describes the development of an EDS technique to measure the thickness of electroless nickel deposits on gold substrates. Although elaborate correction techniques have been developed for thin-film measurements by x-ray analysis, the thickness of electroless nickel films can be dependent on the plating bath used. Therefore, standard calibration curves were established by correlating EDS data with thickness measurements that were obtained by contact profilometry.

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