bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subcalcic, Fe-rich amphiboles in meta-dolerites, Glenrock Station, NSW, Australia
Authors: Offler R. 
Published: December 2006

AbstractSub-greenschist facies metamorphism has produced unusual subcalcic, Fe-rich actinolitic amphiboles in meta-dolerites from the Glenrock Station area, NSW. They show edenite, riebeckite, ferri-tschermakite and Ti-tschermakite coupled substitutions. Their high Fe content is attributed to highaFe2+andaFe3+in the fluid phase produced during the breakdown of clinopyroxene, hornblende, magnetite, and ilmenite. The highaFe2+led to Fe led to Fe2-occupying theBsite, resulting in the formation of subcalcic amphiboles. Variation inaFe2+,aFe3+,aMg,aSi,aAl, andaCa, in different domains resulted in the crystallization of chemically inhomogeneous amphiboles.
Platy phlogopite from blast-furnace slags
Authors: Wearing E. 
Published: December 2006

AbstractPhlogopite mica has crystallized from blast-furnace slags at atmospheric pressure. Its chemistry is characterized by an excess of Na and K over their normal stoichiometric content, which is attributed to a composite association between phlogopite and glass. The diffraction pattern indicates that the phlogopite has a preferred orientation around the a-axis. Scanning electron microscopy shows that this phlogopite consists of numerous small platelets, which probably have their a-axes aligned.
Sulphide mineralogy of the Tomnadashan copper deposit and the Corrie Buie lead veins, south Loch Tayside, Scotland
Authors: Pattrick R. A. D. 
Published: December 2006

AbstractCopper mineralization at Tomnadashan is associated with granitic lenses intruded into a small Caledonian diorite body. The mineralization occurs as disseminations and irregular veinlets and mainly comprises pyrite, chalcopyrite, tetrahedrite-tennantite, calcite, and quartz. There are small inclusions of bismuthinite, galena, aikinite [(Cu,Pb,Fe,Bi)S3], and a mineral with a chemistry similar to hodrushite (Cu8Bi12S22). The tetrahedrite contains up to 6.1 wt. % bismuth.Four km to the south, at Corrie Buie, are quartz veins, hosted by meta-limestones, containing galena with minor amounts of chalcopyrite, pyrrhotite, sphalerite, electrum, schirmerite, and lillianite homologues.The mineralogy of both deposits is consistent with that associated with acid magmatism. There are mineralogical similarities between the two deposits but the style of mineralization at Tomnadashan suggests a limited hydrothermal system and therefore the Corrie Buie veins may be related to felsic intrusives to the south.
Celadonite-aluminous-glauconite: an example from the Lake District, UK
Authors: Loveland P. J. , Bendelow V. C. 
Published: December 2006

AbstractAn occurrence of a celadonite-like mineral in a weathered basalt in the Lake District has been investigated by X-ray diffraction, X-ray fluorescence, electron microprobe, and infra-red spectroscopic methods. The bulk composition of the mineral corresponds to an aluminous-glauconite. The data show that the mineral is most probably a celadonite-muscovite or celadonite-illite mixture, although a celadonite-phengite cannot be entirely discounted. Approximately 10% smectite layers are also present. The results suggest that re-examination of many aluminous glauconites may show them to be mixtures of this type.
Mineral chemistry of regional chloritoid assemblages in the Chlorite Zone, Lycian Nappes, South-west Turkey
Authors: Ashworth J. R. , Evirgen M. M. 
Published: December 2006

AbstractIn the Ören area at the base of the Lycian Nappes, chloritoid is common on a regional scale. Mn and inferred Fe3+contents are low. Chloritoid + quartz occur rather than the more hydrous equivalent pyrophyllite + chlorite, Fe/(Fe + Mg) values in chlorite ranging down to 0·27. Calcite and dolomite, which coexist with chloritoid and pyrophyllite, give a temperature estimate of 350± 30°C, implying moderate to high activities of water for pyrophyllite stability. Muscovite-paragonite geothermometry is unreliable. Mg/Fe distribution coefficients between chloritoid and chlorite differ systematically from literature values from higher grades (biotite and garnet zones). Intensity of colour in chloritoid correlates with inferred Fe3+content, which decreases outwards in grains showing prograde growth zoning.
Garnet websterites and associated ultramafic inclusions from a nepheline mugearite in the Walcha area, New South Wales, Australia
Authors: Stolz A. J. 
Published: December 2006

AbstractA nepheline mugearite dyke in the Walcha area, New South Wales, contains xenoliths of Cr-diopside lherzolite, garnet- and spinel websterites, and two- pyroxene-garnet granulites. The Cr-diopside lherzolite xenoliths are regarded as refractory upper mantle which finally equilibrated at c. 950–980°C. The garnet websterites are considered to represent spinel websterite segregations from an Mg-rich olivine tholeiite magma at 14–16 kbar which on isobaric cooling to 1000–1050°C passed into the garnet pyroxenite stability field. Spinel-amphibole websterites which probably last equilibrated at c. 950°C and pressures of 9–12 kbar have dose mineralogical affinites with the Cr-diopside lherzolite xenoliths. The mafic granulites may represent metamorphosed crystal segregates resulting from relatively large degrees of crystallization of tholeiitic basaltic magma which finally equilibrated at c. 14 kbar and 1000°C Subcalcic clinopyroxene and spinel megacrysts crystallized from the host nepheline mugearite at c. 13–20 kbar.
Mineral chemistry of coexisting phases from shonkinitic rocks, Salem, Tamil Nadu, India
Authors: Friend C. R. L. , Janardhan A. S. 
Published: December 2006

AbstractGabbroic-textured shonkinitic rocks of unknown age cut deformed Archaean dunites and peridotites in the area immediately north of Salem. Magnesite formation post-dates their intrusion. The location of these rocks and the magnesite is thought to be controlled by the intersection of two major basement lineaments. A sequence of crystallization of the minerals and rocks from early undersaturated to late oversaturated rocks is established. Compositions of the coexisting mineral phases are reported here for the first time. Clinopyroxenes, which are relatively unevolved, commonly coexist with olivine (chrysolite) and sanidine. Bronzite, often intergrown with magnetite and green spinel, is occasionally present. In the most undersaturated rocks nepheline-sanidine fingerprint intergrowths occur, whilst perthitic sanidine, albitic plagioclase, and quartz are present in over-saturated rocks. Late in the crystallization sequence, in over-saturated rocks, PH2O appears to have increased allowing the formation of amphibole as well as clinopyroxene.
Zaisho—a pallasite containing pyroxene and phosphoran olivine
Authors: Buseck Peter R. , Clark Jim 
Published: December 2006

AbstractThe Zaisho meteorite, one of only four known pallasite falls, contains pyroxene, which is rare in pallasites, and it is only the fourth meteorite known to contain phosphoran olivine. Except for a recent report by Goodrich (1984) such olivine appears to be restricted to pallasites, and to those containing the rare Mg phosphate, farringtonite. It is unique among olivines in having P in tetrahedral sites and having vacancies, for charge balance, in octahedral sites. Zaisho also contains stanfieldite and a phosphate having a composition between that of stanfieldite and farringtonite. Its metallographic cooling rate is similar to that of many other pallasites, but its average olivine composition, Fa18.3, places it in a small group with more Fe-rich olivines than most pallasites.
Clay and pyrite transformations during ignition of pulverised coal
Authors: Hubbard F. H. , McGill R. J. , Dhir R. K . , Ellis M. S. 
Published: December 2006

AbstractClay minerals are the principal reactive, non-combustible, phases present in the pulverized coal burned in power station furnace units. Despite the short heating time involved, the clay mineral impurity is wholly transformed in the ignition.Illitic clays are partially melted, fluxed by water and potash, to produce an alumino-silicate melt phase. The melt is frothed by the synchronous production of carbon dioxide in an iron oxide catalysed oxidation of associated carbonaceous matter. This produces the hollow, gasfilled, glass-walled spheres (cenospheres) characteristic of pulverized fuel ash (PFA). Partial, primary devitrification crystallization of mullite and quartz from the high-alumina glass is general and the extent of devitrification may influence the pozzolanic efficiency of the PFA cenospheres.Without the advantage of potash fluxing, the kaolinite lattices are dehydrated and transformed, without melting, to amorphous aluminosilicate and crystalline mullite.Oxidation of pyrite leads to coating of cenospheres by condensed magnetite and the emission of sulphur dioxide in the flue gases.
Primary baddeleyite (Zr02) in kimberlite from Benfontein, South Africa
Authors: Scatena-Wachel D. E. , Jones A. P. 
Published: December 2006

AbstractBaddeleyite was found during an electron microprobe study of kimberlite from the Benfontein Sills, which are famous for their igneous carbonate and cumulus features. Based on its close textural association with both groundmass and cumulus oxides (spinels, ilmenite, perovskite), the baddeleyite appears to be primary and crystallized directly from the kimberlite magma. The baddeleyite is remarkably pure, with average ZrO2 and HfO2 of 96.4±1.3 and 1.72±0.08 wt. % respectively. Minor element ranges found were: TiO2 0.32–0.80, CaO 0.31–0.80, FeO 0.43–1.31, MgO 0.06–0.24, SiO2 0.04–0.19, Cr2O3 0–0.07, and Al2O3 0–0.10 wt.%. Several additional trace elements were sought (Ce, Cs, Mn, Nb, Nd, Sr, Y, Yb, and U) but were not detected.
Jeppeite, a new K-Ba-Fe titanate from Walgidee Hills, Western Australia
Authors: Pryce M. W. , Hodge L. C. , Criddle A. J. 
Published: December 2006

AbstractJeppeite, a new mineral, similar in composition to and overgrown on priderite, has been found in the lamproite plug of Walgidee Hills (18° 19′ S, 124° 51′ E), Western Australia. The mineral is named for the discoverer, Dr J. Jeppe. It is monoclinic, C2/m, a 15.453 b 3.8368 c 9.123 Å β 99.25°, strongest powder lines 4.50(002) (4), 3.07(310) (10), 2.99(003,31) (10), 2.961(20) (4), 2.812(311,112) (10), 2.091 (6), 2.074 (6), 1.919 (8) similar to artificial K2Ti6O13. The sparse eluvial crystals are black, elongated along b, bounded by {100}, {20} faces (Λ 45°) and {010}; perfect 100 and good 20 cleavages or partings, submetallic lustre, pale-brown streak, brittle, and cleave into (100) flakes. Dobs 3.94, Dcalc 3.98. Colour values for illuminant C from reflectance spectra for Rp, Rb, and Rθ are: Y% 13.3, 14.4, 16.6; λd 474, 473, 475; and Pe% 5.1, 4.5, 4.3. Refractive indices from reflectances at 590 nm in air are 2.13, 2.21 and 2.35. In thin section, αΛα10° blue, β = b dark greenish brown almost to black, γ = c brown. Bireflectance and birefringence positive. H 5–6, VHN100 orientation dependent; for indentations normal to b 664–773.Jeppeite is common in the lamproite as prismatic to acicular aggregates associated with priderite, richterite, shcherbakovite, wadeite, perovskite, and apatite in a green and white celadonite and chlorite matrix, with a little calcite and sphene, after olivine, pyroxene, and leucite.Electron probe analysis, using Fe, Ti, nepheline, and benitoite standards, gave K2O 8.47, BaO 17.35, TiO2 69.29, Fe2O3 (total Fe) 4.74, sum 99.85%; (Mg, Na, Zr detected). This analysis calculates to (K1.15,Ba0.73)Σ1.88 (Ti5.56, Fe3+0.38)Σ5.94O13, or ideally, (K,Ba)2(Ti,Fe)6O13.
Sweetite, a new mineral from Derbyshire
Authors: Clark A. M. , Fejer E. E. , Couper A. G. , Jones G. C. 
Published: December 2006

AbstractSweetite, naturally occurring Zn(OH)2 with tetragonal symmetry, has been found at Milltown, near Ashover, Derbyshire. It occurs as colourless or whitish bipyramids up to 1 mm in size scattered over the surface of colourless fluorite cubes. The cell dimensions are α 8,222 and c 14.34Å with Z = 20. The strongest lines of the X-ray powder pattern are (d, I, hkl): 4.53 37 (112); 3.572 60 (004,202,211); 2.922 100 (213,220); 2.708 18 (105,204); 2.257 17 (224,215,321); 1.840 11 (226,420,413); 1.764 24 (316). Sweetite is uniaxial negative, ω 1.635, ɛ 1.628. Dmeas is close to 3.33 and Dcalc 3.41. Chemical analysis gave 84.3% ZnO and 17.0% H2O, while theoretical figures for Zn(OH)2 are 81.9 and 18.1% respectively.
Straczekite, a new calcium barium potassium vanadate mineral from Wilson Springs, Arkansas
Authors: Evans Howard T. , Nord Gordon , Marinenko John , Milton Charles 
Published: December 2006

AbstractStraczekite, a new calcium barium potassium vanadate from Wilson Springs (formerly Potash Sulfur Springs), Arkansas, occurs as a rare secondary mineral in fibrous seams in gangue. The dark greenish-black crystals are very soft, thin laths up to 0.5 mm in length, forming thick masses. No single-crystal X-ray patterns could be obtained, but good electron diffraction patterns yielded a monoclinic unit cell in space group C2/m, C2, or Cm. The cell parameters were refined by least squares analysis of Guinier-Hägg X-ray powder data: a 11.679(2), b 3.6608(4), c 10.636(2)Å, β = 100.53(4)° (strongest lines are: 003, 3.486, 100; 001, 10.449, 50; 020 1.8306, 50; 01/510, 1.9437, 15; 111/03, 3.255, 10; 311/12, 2.492, 10; 021, 1.8030, 10). Chemical analysis yields the formula: (Ca0.39Ba0.31K0.33Na0.11)(V1.594+V6.315+Fe0.103+)O20.02(H2O)2.9. The calculated density is 3.21 g/cm3. The mineral conforms to a series of synthetic vanadium bronzes, typified by Ag1-xV2O5 of known structure. It represents a new series of layer vanadate minerals of general formula MxV8O20·yH2O, similar in properties but distinct from the hewettite series (MxV6O16·yH2O).
Some aspects of Tertiary acid magmatism in NE Ireland
Authors: Meighan I. G. , Gibson D. , Hood D. N. 
Published: December 2006

AbstractGeochemical data (including REE determinations) are presented for all five Mourne Mountains granites and three Northern Ireland rhyolites. These confirm (1) the extremely fractionated nature of some of the rocks (Sr and Ba < 10 ppm, Rb > 400 ppm, Eu/Eu* < 0.1, and K/Rb < 100), and (2) a major revision to the outcrops of the E. Mourne granites G1 and G2 in which much of the former is reclassified as G2. Combined petrographic and geochemical studies have also indicated that magmatic pulses were involved in the emplacement of Mourne intrusions G2 (Revised)-G5 inclusive.The N. Ireland Tertiary acid rocks exhibit general geochemical similarities to their analogues elsewhere in the British Tertiary Igneous Province (in which Sr is generally < 100 ppm and CeN/YbN generally < 8 with Eu/Eu* often < 0.6), but as a suite the Mourne granites are enriched in Rb and some other LIL elements relative to their N. Arran counterparts.The more fractionated acid magmas of NE Ireland are believed to have evolved from primitive granitic parent liquids by crystal fractionation at depth which involved major and accessory phases (including zircon and allanite). In the Mourne (and County Antrim) areas the primitive acid compositions lie at the ends of basaltic (tholeiitic) differentiation series, and in the Mourne central complex there is a complete geochemical sequence from basic rocks through intermediate members to primitive and ultimately highly evolved, subalkaline, granitic intrusions. It is concluded that the data are consistent with the Mourne granites and Northern Ireland rhyolites being essentially basaltic differentiates, although Sr isotope evidence indicates some (probably minor) crustal involvement.
An X-ray determinative method for the divalent cation ratio in the triphylite-lithiophilite series
Authors: Fransolet Andrié-Mathieu , Antenucci Diano , Speetjens Jean-Marie , Tarte Pierre 
Published: December 2006

AbstractThe powder diffractograms of twenty wet chemically analysed samples in the isomorphous triphylite-lithiophilite series and five synthesized members with Fe/(Fe + Mn) = 1, 0.75, 0.50, 0.25, and 0.0, were recorded. Their unit cell dimensions were accurately refined in order to find a reliable method for semi-quantitative determination of the divalent cation content of these minerals. A multivariate best fit analysis based on Kummell’s procedure shows the marked influence of Fe2+ and Mg2+ on the cell dimensions, as well as that of small amounts of Fe3+ substituting for Mn2+, following LiMn2+ → □ Fe3+. The best representation of the correlation between chemical composition and cell parameters is given by the equations:a = 6.1041 − 0.0245 Fetot − 0.049 Mg2+b = 10.4511 − Fetot − 0.082 Mg2+c = 4.7400 − 0.0130(Fe2+ + Mg2+) − 0.025 Fe3+.No evidence of non-linearity has been found for the variation of the three cell dimensions with the chemical composition. Assuming the absence of appreciable amounts of Mg2+, the following set of equations is proposed: Fetot = 41(6.104–a); Fetot = 35(10.451–b); Fetot = 77(4.740–c) in which the c dimension gives a relatively poor estimate.Two sets of determinative graphs were constructed, one based on the cell parameter variation, and the other on the 311, 222, and 142 reflection angular positions, v. the total iron content of these minerals. These two methods, whose reliability is examined, can be used for determination of the divalent cation content, provided the samples contain less than about 0.5 wt.% Na2O, 0.5 wt.% CaO, and 3 wt. % Fe2O3, and are homogeneous.
Two varieties of lithiophorite in some Australian deposits
Authors: Ostwald J. 
Published: December 2006

AbstractElectron probe microanalyses carried out on thirty areas of lithiophorite (Al,Li)MnO2(OH)2 from five Australian localities indicate wide variations in its Ni, Co, Cu, and Zn content. The concentration of these elements varies inversely with the alumina content, though there is a marked change in their concentration at 18% alumina, suggesting the existence of two varieties of lithiophorite with differing concentration of transition elements. EPMA line scans also indicate definite changes in Co content in lithiophorite grains less than 0.2 mm in dimension. The variations in alumina and transition elements may be explained if lithiophorite is considered to be an irregular mixed-layer-lattice intergrowth of pure lithiophorite with members of the recently discovered asbolane-type minerals.
Tin-bearing sulphides from St Michael's Mount and Cligga Head, Cornwall
Authors: Moore F. , Howie R. A. 
Published: December 2006

AbstractThe result of electron probe microanalyses, along with X-ray and optical data obtained for tin sulphides from two different localities in south-west England indicate that the mineral hitherto described from St Michael’s Mount as stannite is in fact kesterite, Cu2(Fe0.23Zn0.77)SnS4. The yellow ‘stannite’ reported from this locality proved to be stannoidite, Cu8(Fe2.39 Zn0.61)SnS2S12. Kesterite, Cu2(Fe0.09Zn0.90SnS4, and zincian stannite, Cu2(Fe0.63Zn0.38)SnS4, are also reported from Cligga Head. It is suggested that a more cautious approach should be taken in identifying these tin sulphides solely on their optical properties.
Mpororoite and anthoinite from the Kara mine, Tasmania
Authors: Matsubara Satoshi , Kato Akira , Nagashima Kozo 
Published: December 2006

AbstractThe first occurrence of mpororoite and anthoinite outside the African Continent has been found in an altered skarn from the Kara mine, Tasmania, forming a white powdery mixture of the two minerals pseudomorphing scheelite. The wet chemical analysis of the mixture shows WO3, Al2O3, and H2O to be the essential constituents, proving the non-essential nature of Fe2O3 in mpororoite; the original mpororoite contained high Fe2O3 substituting for Al2O3. The thermal treatment of the mixture at 100°C for 6 hours in air brings about the conversion of mpororoite into anthoinite, which re-hydrates into mpororoite, although the associated anthoinite does not. The source of Al is ascribed to the decomposition of aluminian andradite in the skarn.
Thermal expansion behaviour of beryllonite [Na(BePO4)] and trimerite [CaMn(BeSiO4)3]
Authors: Henderson C. M. B. , Taylor D. 
Published: December 2006

AbstractThe thermal expansions of trimerite and beryllonite have been determined up to 800°C. No anomalies were observed in the thermal expansion curves but the expansion coefficients for beryllonite are approximately twice those of trimerite. The thermal expansion behaviour of the minerals is interpreted in terms of a tetrahedral tilting model with the main change in apparent tilting being about the monoclinic 010 plane, i.e. the 0001 pseudo-hexagonal plane.
Mineralogical data on a multiple intrusion in the Rustenburg Layered Suite of the Bushveld Complex
Authors: Davies G. , Cawtnorn R. G. 
Published: December 2006

AbstractMineralogical and chemical data are presented on an intrusion of a hypersthene gabbro body into coarse-grained noritic cumulates of the critical zone, which occurs at the margin of the Rustenburg Layered Suite of the Bushveld Complex. Two types of contact relations are found between the above two rock suites: (1) a clearly cross-cutting contact is observed on the southern margin of the hypersthene gabbro body close to the interface between the layered suite and the floor rocks; (2) a diffuse heterogeneous contact is found on the north-western limb of the body which is further into the complex. Field observations and chemical data suggest that, at the time of the hypersthene gabbro injection, the surrounding cumulates were above ambient temperatures. The difference in the contacts described above is probably related to the prevailing temperature gradient at the time of emplacement. The cumulate rocks further into the complex were at a higher temperature than those closer to the margin.Trace element chemistry and phase relations in the basalt tetrahedron indicate that the hypersthene gabbro is genetically unrelated to the cumulate rocks which it intrudes. The body probably represents an offshoot of the magma from which the upper zone of the Rustenburg Layered Suite crystallized.
The composition of diopside solid solutions, and of liquids, in equilibrium with forsterite, plagioclase, and liquid in the system Na2O-CaO-MgO-Al2O3-SiO2 and in remelted rocks from 1 bar to 12 kbar
Authors: Biggar Gordon M. 
Published: December 2006

AbstractSubsolidus diopside compositions and coexisting diopside and liquid compositions which are also in equilibrium with anorthite and forsterite in the system CaO-MgO-Al2O3-SiO2 were determined by X-ray diffraction and by electron microprobe in samples equilibrated at 1 bar and at 7 kbar. Along with previous data from the literature and using a recently published grid relating diffraction peaks to composition, results from both techniques are satisfactorily reconciled. At 1 bar, diopside composition (moles, Di = CaMgSi2O6, En = Mg2Si2O6, CaTs = CaAl2Si2O6) in equilibrium with anorthite, forsterite, and spinel (analogous to alkali basalts) are close to Di79CaTs20En1 and those in equilibrium with anorthite, forsterite, and pigeonite (analogous to tholeiitic basalt) are close to Di75CaTs3En22. At 7 kbar the equivalent compositions are Di69CaTs28En3 and Di69CaTs26En5 respectively.In the system CaO-Na2O-MgO-Al2O3-SiO2, electron microprobe analyses of augites and liquids at 1 bar confirm the changes expected in the loci of liquids and show that the low Na2O (< 0.50 wt.%) augites are similar to those in CaO-MgO-Al2O3-SiO2. At 7 kbar the orthopyroxene field has expanded sufficiently and augite was not encountered in the limited range of samples studied.In remelted rocks the augite compositions at 1 bar are similar to the compositions of augites in low pressure effusive rocks. At 2–15 kbar, the available data in the literature for dry basalts show that experimentally recrystallized augites are very sub-calcic and very aluminous, and no natural equivalents exist in plutonic gabbros or in ophiolitic rocks. This discrepancy is not resolved but either the experimental pyroxenes are metastable or the pyroxenes presently in the rocks are not the pristine compositions.