 | Gloaguen, Eric, Branquet, Yannick, Boulvais, Philippe, Moëlo, Yves, Chauvel, Jean-Jacques, Chiappero, Pierre-Jacques, Marcoux, Eric (2007) Palaeozoic oolitic ironstone of the French Armorican Massif: a chemical and structural trap for orogenic base metal–As–Sb–Au mineralisation during Hercynian strike-slip deformation. Mineralium Deposita, 42 (4) 399-422 doi:10.1007/s00126-006-0120-4 | Journal (article/letter/editorial) | | the Saint-Aubin-des-Châteaux quarry (Armorican Hercynian belt, western France), an epigenetic hydrothermal...de Saint Amand, BP 6759, 45067 Orleans Cedex 2, France e-mail: e.gloaguen@brgm.fr P. Boulvais : J.-J....CNRS/Université de Rennes 1, 35042 Rennes Cedex, France Y. Moëlo Laboratoire de Chimie du Solide, Institut...la Houssinière, BP 32229, 44322 Nantes Cedex 3, France P.-J. Chiappero Département Histoire de la Terre...d’Histoire Naturelle, 61 rue Buffon, 75005 Paris, France Present address: E. Gloaguen BRGM, 3, avenue Claude-Guillemin |  | | Journal (article/letter/editorial) | | Namaqua-aged gneissic fabrics defined by grain-flattening of quartz and feldspar in the equigranular leucogneisses...Gneisses were first recognised and mapped by Du Plessis (1979) as the “Yas Granite” and “Schuitdrift Granite”...well exposed in a small defunct dimension stone quarry, situated in a small hill about 500 m west of the...Southern Farms (Figure 1, 28°33’52”S; 19°45’59”E). The quarry is easily accessed via a short track or on foot...Naros Granodiorite (~1 110 Ma, Komsberg Suite; Du Plessis, 1986; Bial et al., 2015; Macey et al., 2015; Smith |  | | Journal (article/letter/editorial) | | nonkuselonkusie@gmail.com ABSTRACT In the Bandelierkop Quarry (South Marginal Zone of the Limpopo belt) two generations...crystallize to nano-granites, which consist of mica, quartz, feldspars and their polymorphs (Cesare et al....plagioclase in magma accumulation sites in the source. Quartz is proposed to co-precipitate with plagioclase...growth in the residuum and the crystallization of quartz and plagioclase in the melt filled structures (Nicoli...from the sites of magma accumulation following quartz and plagioclase crystallization, led to the preservation |  | | Journal (article/letter/editorial) | | folded Palzeozoic rocks continuous with those of Brittany, and forming part of the Armorican massif. In...breccia { ph Metam orphic Phtanite (Chalcedo nic quartz). Xv Metamo rp h ic phyllites a nd crus hed sandstones...conglomerates; coal-bearing beds of Littry and Plessis. Visean: Regneville limestone with Chonetes comoides...of pebbles of Brioverian sandstones or of vein quartz in a matrix of red sandstone (conglomerates and...which have been worked at Littry (Calvados) and at Plessis near Carentan. Andesitic lava flows are intercalated |  | | Journal (article/letter/editorial) | | 1937; Thompson et al. 1987; Diedericks and Du Plessis 1995; Aharonov et al. 1997; Clennell 1997). These...that melts to leave a residue of predominantly quartz, feldspar, and garnet. At moderate melt fraction...migmatite from the migmatitic core of the southern Brittany metamorphic belt (Fig. 1a, Brown 1983; Jones and...crystallization include optically continuous, interstitial quartz (interstitial-xenomorphic texture) between plagioclase...show well-developed euhedral crystal faces, and quartz films along plagioclase-plagioclase grain boundaries |  | | Book (volume) | | l’Institut Muséum d’histoire naturelle DE LA FRANCE ET SES COLONIES DK description physique et chimique...strüvérite et la inonazite. MINÉHALÜGIE DE IA FRANCE 4 lima paru dès le premier abord vraisemblable...rappelant certaines crocidolites. On y voit associés du quartz, de la pyrite, de l’albite et parfois des mouches...de Tamatave, des veinules de calcite, pyrite, quartz, associés des plaquettes de xyloLile brun ressemblant...0;09 1120 10,90 : ana- MlNKliALOGIK DK (i FRANCE ],A (>nOUPE DE L’APATÏTE APATITE Anjou. (T |  | | Journal (article/letter/editorial) | | Jansen (19821 gives a maxtmum of 6000 m. and du PlessIs ( 1987) a figure of 7000 m or (quoted in a paper...T%zkelI(1975); De Bruiyn (1971a. 1971b. 1972a. 1972b); Du Plessis (1972a. 1972b): Jansen (1969,1970a, 1970b. 1975a...in the MainBasin. and correlates sequences. Du Plessis ( 19871 studied rocks lying to it with the Wilge...Sterk River Formation grades laterally into the du Plessis supported Jansen’s original theories of Alma Formation...berg Formation In the southwest. These in turn Plessis and Walraven (19901 suggest a pull-apart grade |  | | Journal (article/letter/editorial) | | specimens featured here were collected by Herman du Plessis HE MOUNTAIN KINGDOM OF LESOTHO is located in...Gauteng, South Africa brucec@uj.ac.za HERMAN du PLESSIS 10 Howick Gardens Webb Street, Farramere Benoni...round, thatched huts is on the left. Herman du Plessis photo, January 2017. 306 ROCKS & MINERALS Figure...Figure 2. Stilbite on drusy, botryoidal quartz, 4 cm, Butha-Buthe district, Lesotho. Bruce Cairncross...geology at the University of Johannesburg. Herman du Plessis is an avid field collector. Most of his mineral |  | | Journal (article/letter/editorial) | | equigranular but can, rarely, be strongly porphyritic. Quartz, plagioclase, antiperthite, hornblende and biotite...Variably oriented younger discrete shear zones and quartz-filled faults cross-cut the pluton. U-Pb zircon...been mapped as the “Stolzenfels Enderbite” by Du Plessis (1979, 1986), Moen and Toogood (2007) and Macey...(~1140 Ma, Moen and Toogood, 2007) is a garnet-quartz-feldspar gneiss with a moderate Namaqua fabric...granodiorite and rare diorite. The rocks are generally quartz-rich (~30 to 35%) and contain plagioclase (An45 |  | | Journal (article/letter/editorial) | | SILURIAN-DEVONIAN BOUNDARY, FROM VENDEE (WESTERN FRANCE) J.J. PEUCAT’, ’ Centre Amoricain F. PARIS’ d’Etude...GCochimie-Rennes CBdex (France) Universite de Rennes Z, GRECO 7 du C.N.R.S. F-35042 Rennes Cedex (France) Universite...Universite de Poitiers, F-86022 Poitiers Cedex (France) for publication June 3, 1986) Abstract Peucat, J.J...Silurian-Devonian boundary, from Vendee (western France). In: G.S. Odin (Guest-Editor), Calibration of...of Bohemia (Czechoslovakia) and Artois (northern France). On the other hand, closely related carbonaceous |  | O'Hara, Matthew J., Kellogg, Cyndi M., Parker, Cyrena M., Morrison, Samuel S., Corbey, Jordan F., Grate, Jay W. (2017) Decomposition of diverse solid inorganic matrices with molten ammonium bifluoride salt for constituent elemental analysis. Chemical Geology, 466. 341-351 doi:10.1016/j.chemgeo.2017.06.023 | Journal (article/letter/editorial) | | across a range of inorganic sample types: glass, quartz, zircon, soil, and pitchblende ore. Method performance...(NH4F·xHF), where x is commonly 1, 1.5, and 2 (du Plessis et al., 2016; Rakov and Mel'nichenko, 1984). Ammonium...solids including glass, the refractory minerals quartz and zircon, and NIST soil and AQCS uranium ore...specific material being decomposed. For glass and quartz, required ratios are consistent with predictions...materials Milled samples of the refractory minerals quartz (SiO2) and zircon (ZrSiO4) and also an amorphous |  | | Journal (article/letter/editorial) | | assisted in the exposure of an important vein of white quartz, often radiate.On its course also are the ferruginous...appearance du e t o the alternation of bands of quartz and biotite, but most usu ally th e metam orphic...beds of conglomerate with rolled pebbles of white quartz, which would tend to prove that they came from...Mail d' Angers in the form of mottled slates with quartz-conglomerates termed poudingues de Loire, intercalated...of Beaucouze, crossing the Maine to reach the Plessis by La Croix Verte. West of the Maine this band |  | | Journal (article/letter/editorial) | | René Heyn 1, *, Abraham Rozendaal 1 , Anton Du Plessis 2 1 2 * and Carene Mouton 1 Department of Earth...control Citation: Heyn, R.; Rozendaal, A.; Du Plessis, A.; Mouton, C. Characterization of Coloured Gemstones...Topaz 6 mm 0.83 Trillion 3 Hydro Amethyst Quartz 12 mm 5.67 Cushion rose cut 3 Tanzanite Zoisite...CT conditions, following the guidelines of du Plessis et al. [28]. These included three blue diffused...1–17. [CrossRef] Rozendaal, A.; le Roux, S.G.; du Plessis, A.; Philander, C. Grade and product quality control |  | | Journal (article/letter/editorial) | | more prominent towards the top of the formation. Quarry on Hartenbosch 217 north of Mossel Bay. (E) Very...some of the clasts showing in-situ fracturing. Quarry on Hartenbosch 217. (G) Cross-bedded sandstone...conglomerate showing some water escape structures in the quarry on Hartenbosch 217. SOUTH AFRICAN JOURNAL OF GEOLOGY...colour (Figure 3B and D). The clasts are mainly quartz arenite from the Table Mountain Group, phyllite...instances also Figure 5. (A) Intra-basinal fault in quarry on Hartenbosch 217 north of Mossel Bay. (B) Northward |  | | Journal (article/letter/editorial) | | 362±370 Ó Springer-Verlag 1997 ARTICLE G. du Plessis á G.J. Jonck á R. Kruger Potential low-grade iron...in the Editorial handling: P.G. Eriksson G. du Plessis (&) á R. Kruger Geology, Iron Ore Business, Iscor...coarser-grained meta-BIFs, consisting essentially of quartz with magnetite, the dominant iron-bearing mineral...lens-shaped bodies of serpentinite and chromitite (Du Plessis 1996). Intrusive pegmatite veins and diabase dykes...thin bands of magnetite and quartz. Interbedded waste material includes quartz-feldspar gneiss, grunerite-banded |  | | Journal (article/letter/editorial) | | shown, based on authors’ unpublished data. (du Plessis, 1987; Callaghan et al., 1991), a long-lived, lithospheric-scale...microgranophyre and discrete, finegrained crystals of quartz and K-feldspar. Geochronology Baddeleyite was extracted...Mokapane (formerly Potgietersrus) (Figure 2; du Plessis, 1978). Regression through five discordant analyses...Sample JP10z was collected within the Moshaneng Quarry, where the dolerite is currently being exploited...pyroxene fraction from dolerite at the Moshaneng Quarry (Jones and McElhinny, 1966), near our sites JP9 |  | | Journal (article/letter/editorial) | | 1977; Michaluk and Moen, 1991; Keyser and du Plessis, 1993; Schutte, 1994). Where exposed, the granitoid...spillway (Michaluk and Moen, 1991; Keyser and du Plessis, 1993); iii fine- to medium-grained grey or pink...referred to as the Mosita Granite (Keyser and du Plessis, 1993). All the granitoid varieties contain xenoliths...minerals are prominent the rocks may be regarded as quartz diorites. Plagioclase feldspar (albite-oligoclase)...Tables 1, 2 and 3 and located on Figs 1 and 2. quartz make up the bulk of the remaining components and |  | | Journal (article/letter/editorial) | | 1975; Rozendaal et al., 1986; Hartzer, 1989; Du Plessis and Walraven, 1990). There is close agreement amongst...et al., 1988, 1991; Du Plessis, 1990; Du Plessis and Walraven, 1990; Du Plessis 1990) and will not be...hanging wall rocks FW TZ HW Pink-grey Altered quartz, k-spar, plag arkose Ankerite, tourmaline mottling...(mineralized) Pale grey to greenish grey Altered k-spar, quartz, plag arkose Ankerite mottling, chlorite zones...numbers decrease into FW Red to pink-red Altered quartz, k-spar, plag arkose Hematite speckling, finegrained |  | | Journal (article/letter/editorial) | | into coarse crystalline algal laminites with drusy quartz concentrations and with increasing silification...Transvaal were described in detail by Page and Du Plessis (1986). The Mooiplaas mine is situated in the southwestern...cement production plant is located next to the quarry activities. Mined are partly dolomitized giant...Dolerite dikes crosscutting the formation in the quarry area, including the weathered zone along the dikes...with an operating stripping ratio of 2: 1, the quarry moves about a million ton of rock per month. The |  | | Journal (article/letter/editorial) | | basalts and thus the extension, as 2714 • 8 Ma. A quartz porphyry (the Makwassie Formation) towards the...of South Africa (G, Fig. lb) is discussed by Du Plessis and Walraven (1990) who present a model that utilises...distribution and deformation of the Complex. Du Plessis and Walraven base their model on an evaluation...framework of the Bushveld Complex referenced by Du Plessis and Walraven (1990), is the Palala shear zone (Fig...many years. My thanks to you all. Drs. C. P. du Plessis and C.W. Stowe are thanked for their constructive |  | | Journal (issue) | | 81-84 Basaltes, leur altération climatique 85-90 Quartz choqués GEODE 37(2), 04.12 HONA 47(1), 02...Wisconsin; Wavellite from the National limestone quarry near Mt. Pleasant Mills, Snyder Co., Pënnsylvania)...mine, Big Horn Mts., Maricopa Co., Arizona 181-183 Quartz concentrated around altered pyrite 189-191 In memoriam...waar o.a. de Ameib farm ligt. Foto © Herman Du Plessis April 2012. Net zoals bij de Mile 72 werden ook...onder nummer 412/1. Dankwoord Dank aan Herman Du Plessis voor de toestemming om zijn foto te publiceren |  | | Journal (article/letter/editorial) | | ores (Ozkaya et al., 2007; Nurmi et al., 2009; du Plessis et al., 2011). The subsequent oxidation of Fe2+...two-stage reactor configuration recently proposed by du Plessis et al. (2011) was used for biological Fe2+ oxidation...Maghemite/chromite Magnetite Pentlandite Pyrite Pyrrhotite Quartz Talc Vermiculite Violarite Goethite Smectite (nontronite)...jarosites,” Geochim. Cosmochim. Acta 67, 2063-2076. du Plessis, C. A., Slabbert, W., Hallberg, K. B., and Johnson...Ginige, M. P., Cheng, K. Y., Hilario, F., and du Plessis, C. A. (2014a). “Biohydrometallurgical iron oxidation |  | | Journal (article/letter/editorial) | | effectively separated. Selective separation of quartz from pyrite and chalcopyrite was also achieved...Natarajan and Das (2003) compared the settling rates of quartz, pyrite and chalcopyrite with cells that had been...nickel laterite ores (Hallberg et al., 2011; du Plessis et al., 2011). Further studies are required to...in the separation of haematite from a haematite–quartz suspension. Related to the Mycobacteria, the species...conditions, the bacterial cells adhered to both quartz and haematite, leaving both minerals with similar |  | | Journal (article/letter/editorial) | | microCT: Case study Stephan G Le Roux, Anton Du Plessis, Abraham Rozendaal www.elsevier.com/locate/cageo...Cite this article as: Stephan G Le Roux, Anton Du Plessis and Abraham Rozendaal, The quantitative analysis...microCT: case study Stephan G LE ROUX 1, Anton DU PLESSIS 1, Abraham ROZENDAAL 2 1 CT Scanner Facility,...mainly consists of scheelite, pyrite, pyrrhotite and quartz as shown in Figure 5. However this does not indicate...are present in the various cores. 1) Sheelite; 2) Quartz; 3) Pyrite; 4) Pyrrhotite Fig 6: Theoretical X-ray |  | | Report (issue) | | anhedral and subhedral fluorite. Interstitial quartz constitutes on average 20% of the bulk mass of...in length and which are lined with fluorite and quartz crystals are common, while unrnineralised clasts...2% SiO2, 3.06% P2O5 (= 7.23% apatite) (P.G. du Plessis, !SCOR, pers. comm.). Second in importance, the...25% BaSO4, 4.19% P2O5 (= 9.93% apatite) (P.G. du Plessis, ISCOR, pers. comm.). 6 Body C is an irregular...6% SiO2, 0.51% P2O5 and 0.72% BaSO4) (P.G. du Plessis, !SCOR, pers. comm). Between 1953 and 1955 about |
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