bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Eskdalemuir tholeiite and its contribution to an understanding of tholeiite genesis
Authors: Elliott R. B. 
Published: December 2006

SummaryThe Eskdalemuir tholeiite has the following modal composition: glass 42·2 %, felspar 24·4 %, pyroxene 30·6 %), magnetite 2 %, chlorite 1%. The glass has been separated and analysed. It has 70% SiO2 and is of granitic composition. On a selected triangular diagram the plots of the Eskdalemuir rock, its residual glass, and its crystallinc portion are spread along a narrow belt marking the compositions of the Tertiary tholeiites. Because the differences in the chemical compositions of the phrases of the Eskdalemuir tholeiite are produced by crystallization, it is concluded that the variety of composition of the other Tertiary tholeiites is consistent with a genesis controlled by crystallization differentiation.
New occurrences of vanadium minerals (mottramite, descloizite, and vanadinite) in the Caldbeck area of Cumberland
Authors: Kingsbury Arthur W. G. , Hartley J. 
Published: December 2006

SummaryFour new occurrences of vanadium minerals are described. New X-ray powder data are given for descloizite and mottramite, and show appreciable differences. Evidence is brought that the original occurrence of mottramite was not at Mottram St. Andrew, Cheshire, but Pim Hill, Shropshire, and that most if not all specimens labelled Mottram St. Andrew or Cheshire really came from Pim Hill.
The structures of the plagioclase felspars: VII. The heat treatment of intermediate plagioclases
Authors: Gay P. , Bown M. G. 
Published: December 2006

SummaryPrevious work has established that natural ‘low-temperature’ intermediate plagioclases show single-crystal diffraction patterns in which the subsidiary reflections are split into two; the separation of these split reflections appears to be dependent on the composition of the felspar. Several of these specimens have been subjected to varying heat treatments and their diffraction patterns examined.It is found that over the whole composition range the split subsidiary reflections have disappeared after treatment at high temperatures, and only the principal felspar reflections, which are characteristic of an albite-like structure, remain. Natural specimens initially showing anomalous patterns can also be homogenized in this way by suitable heat treatments. A careful study of the mode of disappearance shows that the separation of the subsidiary reflections is unchanged as long as they remain visible.The structural and petrological implications of this work are discussed.
Trace-element distribution in a garnet-chlorite rock from Foel Ddu, near Harlech, Merionethshire
Authors: Mohr P. A. 
Published: December 2006

SummaryAnalytical data on a garnet-chlorite rock and the contained garnet with spectrographic determinations of the trace elements are presented, and the principles determining the distribution of these elements between the garnet and the chlorite are discussed.
Titanomagnetites from a differentiated teschenite sill
Authors: Wilkinson J. F. G. 
Published: December 2006

SummaryMineragraphic, chemical, and X-ray data are presented on the titanomagnetites1 from a differentiated teschenite sill. The minerals are generally homogeneous. The earliest titanomagnetites are Fe3O4.Fe2TiO4.FeTiO3 a solid solutions; the titanomagnetite crystallization trend is one of enrichment in Fe3O4 and FeTiO3 at the expense of Fe2TiO4. The relations of the titanomagnetites to the parent rocks and associated minerals, and their role in basaltic magma iron enrichment are also discussed.
A contribution to the mineralogy of chloritoid
Authors: Snelling N. J. 
Published: December 2006

SummaryChloritoids from the Saxa Vord schists in the Shetland Isles and the Dalradian schists north of Stonehaven have been studied optically and chemically. In both eases monoclinic and triclinic crystals occur with α = b in the monoclinic varieties. Twinning is common with twin axes [110] and [230]. The formula of chloritoid is considered in relation to the structure recently suggested by Brindley and Harrison (1952).
Isokite and triplite from Bohemia
Authors: Fisher D. Jerome 
Published: December 2006

SummaryIsokite (CaMgPO4F), a new mineral homologous with sphene, was described late in 1955 from a Rhodesian carbonatite plug. A fine-grained variety is now reported from Bohemia, where it occurs as a replacement of (probably a hydrothermal alteration product of) coarse medium brown ‘later’ triplites. It is intimately associated with fine-grained apatite that along with quartz formed post-isokite.
Plagioclases from the Juvinas meteorite and from allivalite from the Isle of Rhum
Authors: Game P. M. 
Published: December 2006

SummaryThe optical properties and specific gravity, and the variations in these properties, of analysed plagioclases separated from the meteorite (eucrite) from Juvinas, France, are compared with the corresponding values for a terrestrial plagioclase of almost identical composition from an allivalite from Rhum. The range in properties for the Juvinas plagioclase indicates a compositional range from about Ab35An65 to Ab15An85, but the great majority of grains are bytownite with approximately 83 % (molecular) anorthite.The frequency of occurrence of the twin-laws of the Juvinas plagioclase resembles that of plagioclase from basalts and allied rocks.The variable changes and, in some grains, absence of change in the optical properties shown by the Juvinas plagioclase crystals, after heating to 1100°C. for 48 hours followed by rapid cooling, contrasts with the small but constant optical changes shown by the allivalite plagioclase (for which geological evidence indicates slow cooling) after identical heat treatment. It is inferred that the meteoritic plagioclase grains have had differing thermal histories, and that some grains have been subjected to previous natural quenching.
The powder patterns and lattice parameters of plagioclase felspars. II
Authors: Smith J. V. , Gay P. 
Published: December 2006

SummaryThe angular separations (2θ (131)+2θ (220)−4θand (2θfor 111 analysed plagioclase felspars have been determined from diffractometer records. From An0to An70the petrological environment has a strong influence on these separations, and if the An-content is independently known an accurate estimate of the structural state can he made from the first of these angular separations. From An70to An100there are only small variations in both separations with An-content and structural state. From An85to An100inconsistencies in the data suggest that other factors can influence any interpretation so seriously that only qualitative or semi-quantitative deductions may be made. Consideration of the angular separations and subsidiary reflections of sodie plagioclases from a wide range of geological environments has led to the novel hypothesis that in this composition region even plutonic specimens are in a metastable state with slightly disordered structures.The value to the petrographer of the available methods for the estimation of An- content and structural state is critically discussed. Although it is thought that the standard optical curves in present use are in need of some revision, the determination of optical orientation by universal-stage methods is probably adequate for routine studies. For more detailed investigations, this may be supplemented by X-ray powder data and refractive index measurements, whilst a complete description of the felspar requires the addition both of chemical analysis and single-crystal X-ray work. In particular, the efficacy of the various X-ray methods that have been proposed is discussed, and recommendations of the most suitable method for various composition ranges are made.
The mineral paragenesis and metamorphic status of garnet-hornblende-pyroxene-scapolite gneiss from Ghana (Gold Coast)
Authors: von Knorring O. , Kennedy W. Q. 
Published: December 2006

SummaryThe main minerals (garnet, pyroxene, hornblende, and scapolite) in certain Dahomeyan (Archaean) garnet-hornblende-pyroxene-scapolite gneisses from Ghana have been separated and analysed. Both the garnet and the pyroxene show marked eclogitic affinities, and the rocks are considered to occupy a transitional position between the amphibolite and eclogite facies. The scapolite is a sulphatic variety containing more than 4 % SO3 and is believed to be a product of autometasomatism. A revised scheme for the distribution of mineral facies within the temperature-pressure field of metamorphism is proposed.
New techniques for the universal stage. I. An extinction curve method for the determination of the optical indicatrix
Authors: Joel N. , Muir I. D. 
Published: December 2006

SummaryThis paper describes a development for the universal stage of the extinction curve method for determining the orientation of the optical indicatrix in biaxial crystals. The extinction curve may be defined as the locus of the poles of the extinction directions when the crystal is rotated between crossed polarizers about an arbitrary but fixed axis perpendicular to the microscope axis.When two or more extinction curves, or parts of them, are plotted on a stereographic projection, their intersections give the directions of the axes of the indicatrix, of which at least two are directly accessible. The main application of this new orthoscopic method is to provide a means of refining the orientation of the indicatrix obtained by this or any other method. The accuracy that can be obtained for minerals of low birefringence such as the felspars is considerably greater than with the conventional orthoscopic method.A complete account is given of the details of the plotting procedure.
On the unit cell of calcium potassium sulphate hydrate: synthetic and natural syngenite
Authors: Aruja E. 
Published: December 2006

SummaryThe space group and unit cell of natural syngenite have been redetermined. X-ray powder photographs of natural syngenite and synthetic CaSO4.K2SO4.H2O were found to be practically identical. Optical and d.t.a. data are also given.
X-ray studies of synthetic diamonds
Authors: Lonsdale Kathleen , Milledge H. Judith , Nave Eric 
Published: December 2006

SummaryStudies are described of various specimens of diamonds made by the General Electric Company of New York, and by Allmänna Svenska Elektriska Aktiebolaget, Västeras, Sweden. The G.E. synthetic diamonds always contain single crystal inclusions of nickel or of a Ni-rich face-centred cubic compound. These are strictly parallel to the diamond surrounding them. If the nickel inclusions are twinned on (111), the diamond is similarly twinned; and this is usually the case. It is suggested that epitaxial growth is part of the mechanism of the graphite-to-diamond transformation in the G.E. technique. Other powdered or single-crystal inclusions are also found; some of those correspond to compounds that occur in meteoritic carbon. There is no parallel growth in such cases. The Swedish synthetic diamonds do not contain nickel, but they are generally less well-crystallized than the G.E. specimens. Both, however, give good diffraction spots indicating a well-ordered structure with (except very rarely) no trace of graphite present.
The fibrous zeolite erionite; its occurrence, unit cell, and structure
Authors: Staples Lloyd W. , Gard J. A. 
Published: December 2006

SummaryThe type locality for erionite has been identified and specimens compared with Eakle's original material. New determinations of the physical properties and a chemical analysis have been made. Correlation of X-ray powder and fibre rotation data with electron diffraction of single crystals has shown that the unit cell is hexagonal with a 13·26, c 15·12 Å., space-group P31c, P¯31c, P63mc, P¯62c, or P63/mmc, giving a calculated sp. Gr. of 2·07 and atomic cell contents (Ca, Mg, Na2, K2)4·5Al9Si27O72.27H2O. A structure is proposed for the aluminosilicate frame, with space-group P63/mmc, which gives satisfactory correlation between observed and calculated structure factors for the X-ray fibre rotation pattern.
Yoderite, a new hydrous magnesium iron aluminosilicate from Mautia Hill, Tanganyika
Authors: McKie Duncan 
Published: December 2006

SummaryYoderite occurs as a major constituent in a quartz-kyanite-tale schist, and is a high-pressure phase formed by the reaction Ky + Tc → Yd + Qu. The monoclinic unit-cell, a 8·10 Å., b 5·78 Å., c 7·28 Å., β 106°, space-group P21 or P21m, contains approximately (Mg2·0Ca0·2Fe0·5Al5·3Si4·0O17·6(OH)2·4. The structure appears to be related to that of kyanite, with which the mineral is intergrown; it is not an analogue of staurolite. The three strongest powder lines are 3·50 Å. vvs, 3·03 Å. vs, 2·61 Å. s. Specific gravity 3·39. Subsidiary reflections, similar to those of the intermediate plagioclases, have indices with non-simple fractional values of k. Optical properties are α 1·689 pale Prussian blue, β 1·691 indigo, γ 1·715 light olivegreen, absorption β > α > γ, 2Vγ25°, optic axial plane {010}, γ:[001] ≈ 7° in the obtuse angle β. An interpretation of the colour on the electron-exchange hypothesis Fe2+ ⇌ Fe3+ + e−, is suggested. A kinetic study has been made of the disappearance of the subsidiary reflections in the range 700°C. to 820°C.; further heating to 850°C. produces the metastable appearance of mullite, and at temperatures above 1100°C. the equilibrium anhydrous assemblage indialite + sapphirine appears.
The system CaO-MgO-FeO-SiO2 and its bearing on the origin of ultrabasic and basic rocks
Authors: Wyllie Peter J. 
Published: December 2006

SummaryExperimental data in the system CaO-MgO-FeO-SiO2 suggest that there may be a plateau on the liquidus and solidus of the multicomponent system basalt-peridotite. If this is so, fusion of peridotite would produce only basaltie magmas over a wide temperature range; when the temperature reached a value such that the liquid crossed the threshold of the plateau, there would be a rapid increase in the amount of fusion for small temperature increases, with the formation of picritic magmas; basaltic magmas containing suspended forsteritic olivine crystals could dissolve them if the temperature rose slightly above that of the plateau threshold; a high proportion of a picritic magma would crystallize in a small temperature interval, with the precipitation of forsteritic olivine that was only slightly zoned. These possibilities are compared with current theories, and it is concluded that several petrological axioms may require critical re-examination. An experimental procedure is outlined to determine the shape of the liquidus and solidus in the basalt-peridotite system.
Occurrence of stokesite in Czechoslovakia
Authors: Čech F. 
Published: December 2006

SummaryStokesite was found in a lithium-bearing pegmatite at Ctidružice near Moravské Budějovice in Western Moravia (Czechoslovakia) in a close association with cryptocrystalline cassiterite. The type of its occurrence is described and its X-ray powder diffraction data given. This represents only the second occurrence of this very rare hydrous silicate of tin and calcium.
Electron-optical and electron-diffraction study of a disordered structural state in the transformation goethite-hematite (Plate XX)
Authors: McConnell J. D. C. , Lima-de-Faria J. 
Published: December 2006

SummaryPrevious X-ray observations by J. Lima-de-Faria and P. Gay on the transformation goethite-hematite indicate that in the process of state change at low temperatures, maxima of scattered X-ray intensity occur as satellites to strong and diffuse Bragg maxima due to hematite. These maxima define a repeat distance of about 32 Å. Corresponding satellite maxima have been observed using electron diffraction technique and satellite maxima flanking the direct beam (000) have been used to obtain a direct electron optical image of the disordered state at high magnification. Such photographs show a mainly regular fringe system with spacing of approximately 30 Å. Dislocation patterns were also observed.
On hour-glass sector zoning in clinopyroxene
Authors: Ferguson A. K. 
Published: December 2006

SummaryThe observations of hour-glass sector zoning from four selected clinopyroxenes in undersaturated lavas best fit a model in which the sector zoning is formed due to a structural requirement in a growth direction normal to {100} where a high concentration of silicate units, required to build the silicate chains, is unsatisfied. In these sectors Al substitutes for Si, the charge balance being maintained by octahedral substitutions, of which Ti contributes to the deeper colour of the sectors. The presence of concentric zoning only reflects a change in temperature and a change in the composition of the liquid during crystallization of the pyroxene.
Urea, a new mineral, and neotype phosphammite from Western Australia
Authors: Bridge P. J. 
Published: December 2006

SummaryUrea, a new mineral identical with the artificial compound, occurs as crystals associated with phosphammite, ammonian aphthitalite, and weddellite in guano from Toppin Hill, 123° 56′ E., 28° 42′ S., Western Australia. The urea occurs as elongated tetragonal pyramids, space group , a 5·646, c 4·701 Å, X-ray powder data are given. Optical properties: ω 1·484, ε 1·603. Chemical analysis gave urea, CO(NH2)2 96·0, H2O− 0·46, Na 0.13, K 0·35, Ca 0·07, Mg 0·03, S 0·11, P 0·24, NH3 < 1·0 %, remainder probably mainly H2O+; urea 96 %, impurities 4 %. Type material is preserved in the collection of the Government Chemical Laboratories, Perth, Western Australia.
Tungsten- and antimony-substituted
rutile
Authors: Graham J. , Morris R. C. 
Published: December 2006

Summary
Two occurrences of rutile are reported
from Big Bell in Western Australia containing up
to 5·8 wt % WO3, 1·7 wt %
Sb2O5,
and 1·7 wt % FeO. One occurs in a mica schist, and
the other in a pegmatite, and both contain a fine
intergrowth of ilmenite lamellae. Small grains of
gudmundite are associated with the rutile in the
pegmatite. Microprobe analyses do not conclusively
establish the mechanism of isomorphous
substitution.
Killalaite, a new mineral from Co. Sligo, Ireland
Authors: Nawaz R. 
Published: December 2006

SummaryKillalaite occurs in a thermally metamorphosed limestone at Killala Bay, near Inishcrone, Co. Sligo. It is a secondary mineral and occurs in cavities and veins with calcite or afwillite in spurrite-wollastonite rocks. It is found in well-formed colourless crystals, up to 2 mm long, with a characteristic penetrative twinning observed under crossed nicols as a cross ‘bow-tie’, cleavage (100) perfect, (010) good, (001) poor. The crystals are monoclinic, biaxial, 2Vα26°, refractive index α 1·635 and γ 1·642, optic axial plane (010), β = [010] (elongation), γ: [001] ≈ 16°, density calculated from RI ∼ 2·88, provisional approximate cell dimensions a 9·3, b 9·9, c 7·7 (±0.1 Å), β ∼105° and Z = 2. Electron microprobe analysis gave CaO 57·o, SiO2 39·8; H2O (by difference) 3·2; MgO, Al2O3, and Fe2O3 together < 0·3 weight %, composition 2Ca3Si2O7.H2O. The stronger lines of the X-ray powder pattern are: 3·03, 2·824, 2·724, 2·275, 2·224, 1·688, 1·673, and 1·413 Å. It probably formed in a CO2-deficient hydrothermal environment in the PT range of 350° to 500 °C and 500 to 3500 bars. The mineral is named after the name of the locality, Killala Bay, and should be pronounced as killalahite. Type material is preserved at the Ulster Museum and at the British Museum (Natural History).
An E.S.R. study of natural fluorite containing manganese impurities
Authors: Bailey A. D. , Hunt R. P. , Taylor K. N. R. 
Published: December 2006

SummaryThe electron spin resonance spectrum of a sample of natural, orange-coloured fluorite from Broken Hill, Australia, has been observed and shown to arise from the presence of manganese ions. From an analysis of the structure of this spectrum it has been possible to estimate the various contributions to the ionic energy level splitting and to show that these are in good agreement with comparable results for synthetic material. It is evident that the manganese ions have entered the lattice substitutionally at Ca2+ sites and the nature of this site is discussed.
Survival and Late Effects in Children With Hodgkin's Lymphoma Treated With MOPP/ABV and Low-Dose, Extended-Field Irradiation
Authors: Chow Lionel M.L. , Nathan Paul C. , Hodgson David C. , Jenkin Derek , Weitzman Sheila , Grant Ronald M. , Manson David , Bross Adee , Doyle John J. , Danjoux Cyril , Greenberg Mark L. 
Published: December 2006

Purpose Reduced-intensity protocols for pediatric Hodgkin's lymphoma are aimed at preserving excellent relapse-free survival while decreasing the incidence of late effects. Patients and Methods We retrospectively reviewed the outcome of 123 children treated consecutively for Hodgkin's lymphoma at a single institution. Patients with stages I-IIIB disease received three cycles of mechlorethamine, vincristine, procarbazine, and prednisone (MOPP)/ doxorubicin, bleomycin, and vinblastine (ABV) followed by 15 Gy of extended-field irradiation, while those with stage IV disease were treated with six to eight cycles of MOPP/ABV chemotherapy with or without radiotherapy. Results At a median follow-up of 8.5 years (range, 1.4 to 15.5 years), the estimated 10-year overall survival and event-free survival are 94% (SE, 2.2%) and 88% (SE, 3.1%) respectively. There have been 12 treatment failures and six disease-related deaths. A very large mediastinal mass (≥ 50% of the maximal thoracic diameter) was associated with a 10-year event-free survival of 50% (SE, 14%) compared with 91% (SE, 4.0%) for smaller masses (P < .001). Late cardiopulmonary toxicity is largely absent, and the incidence of hypothyroidism is 14%. There have been no cases of secondary leukemia and four secondary solid malignancies observed to date. Conclusion MOPP/ABV and low-dose, extended-field radiotherapy is an effective treatment for pediatric Hodgkin's lymphoma. With median follow-up of 8.5 years, late cardiopulmonary effects and secondary malignancies from this treatment regimen are infrequent. Continued longitudinal observations, particularly for breast cancer in female patients and gonadotoxicity, will determine whether the goal of decreasing treatment-related complications while maintaining excellent survival has been achieved.