bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Cloud Radiative Feedback, Remote ENSO Forcing, and Entrainment on the Persistence of North Pacific Sea Surface Temperature Anomalies
Authors: Park Sungsu , Alexander Michael A. , Deser Clara
Published: December 2006

The influence of cloud radiative feedback, remote ENSO heat flux forcing, and oceanic entrainment on persisting North Pacific sea surface temperature (SST) anomalies is investigated using a stochastically forced ocean mixed layer model. The stochastic heat flux is estimated from an atmospheric general circulation model, the seasonally varying radiative feedback parameter and remote ENSO forcing are obtained from observations, and entrainment is derived from the observed mean seasonal cycle of ocean mixed layer depth. Persistence is examined via SST autocorrelations in the western, central, and subtropical eastern North Pacific and for the leading pattern of variability across the basin. The contribution of clouds, ENSO, and entrainment to SST persistence is evaluated by comparing simulations with and without each term.

The SST autocorrelation structure in the model closely resembles nature: the pattern correlation between the two is 0.87–0.9 in the three regions and for the basinwide analyses, and 0.35–0.66 after subtracting an exponential function representing the background damping resulting from air–sea heat fluxes. Positive radiative feedback enhances SST autocorrelations (∼0.1–0.3) from late spring to summer in the central and western Pacific and from late summer to fall in the subtropical eastern Pacific. The influence of the remote ENSO forcing on SST autocorrelation varies with season and location with a maximum impact on the correlation magnitude of 0.2–0.3. The winter-to-winter recurrence of higher autocorrelations is caused by entrainment, which generally suppresses SST variability but returns thermal anomalies sequestered beneath the mixed layer in summer back to the surface in the following fall/winter. This reemergence mechanism enhances SST autocorrelation by ∼0.3 at lags of 9–12 months from the previous winter in the western and central Pacific, but only slightly enhances autocorrelation (∼0.1) in the subtropical eastern Pacific.

The impact of clouds, ENSO, and entrainment on the autocorrelation structure of the basinwide SST anomaly pattern is similar to that in the western region. ENSO’s impact on the basinwide North Pacific SST autocorrelation in an atmospheric general circulation model coupled to an ocean mixed layer model with observed SSTs specified in the tropical Pacific is very similar to the results from the stochastic model developed here.
Why Do People Perceive Ingroup Homogeneity on Ingroup Traits and Outgroup Homogeneity on Outgroup Traits?
Authors: Rubin Mark , Badea Constantina
Published: December 2006

People tend to perceive ingroup homogeneity on ingroup stereotypical traits and outgroup homogeneity on outgroup stereotypical traits (e.g., Kelly, 1989; Simon, 1992a; Simon & Pettigrew, 1990). If it is assumed that people use homogeneity ratings to indicate the extent to which groups possess traits, then this stereotype effect may be interpreted as an expression of perceived trait possession (i.e., ingroups possess ingroup stereotypical traits and outgroups possess outgroup stereotypical traits). If it is further assumed that research participants abide by the conversational norm of appropriate quantity (e.g., Bless, Strack, & Schwarz, 1993), then this stereotype effect should be significantly reduced following prior expressions of perceived trait possession. A literature review and two minimal group experiments (Ns = 75, 104) supported this prediction. This evidence is discussed in relation to the outgroup homogeneity effect and self-categorization theory.
Culture and Teasing: The Relational Benefits of Reduced Desire for Positive Self-Differentiation
Authors: Campos Belinda , Keltner Dacher , Beck Jennifer M. , Gonzaga Gian C. , John Oliver P.
Published: December 2006

The authors hypothesized that teasing, a social interaction that benefits relational bonds at the expense of the self, should be viewed as more affiliative, and experienced as more pleasurable, by members of cultures that deemphasize positive self-differentiation. In four multimethod studies, Asian Americans attributed more affiliative intent to teasers and reported more positive target experience than did European Americans. Teaser behavior, attribution biases, and personality did not account for culture-related differences in teasing experience. Rather, childhood teasing may better prepare Asian American children to overlook a tease's affront to the self in favor of its relational rewards. Implications of deemphasizing positive selfdifferentiation in social interaction are discussed.
Mother's Milk: An Existential Perspective on Negative Reactions to Breast-Feeding
Authors: Cox Cathy R. , Goldenberg Jamie L. , Arndt Jamie , Pyszczynski Tom
Published: December 2006

Drawing from an existential perspective rooted in terror management theory, four studies examined the hypothesis that breast-feeding women serve as reminders of the physical, animal nature of humanity and that such recognition is threatening in the face of one's unalterable mortality. Study 1 demonstrated that mortality salience (MS) led to more negative reactions toward a scenario depicting a woman breast-feeding her infant in public, and in Study 2, MS decreased liking and increased physical avoidance of a potential task partner described as breast-feeding in another room. Further supporting the hypothesis that such reactions are rooted in threats associated with human creatureliness, MS in conjunction with a breast-feeding prime led to an increase in the accessibility of creaturely related cognitions (Study 3) and priming human/animal similarities (i.e., creatureliness) led to increased negativity toward a magazine cover depicting a woman breast-feeding her child (Study 4). Implications of this research are discussed.
An attachment to the goniometer for use in the measurement of crystals with complex faces
Authors: Bowman H. L.
Published: December 2006

When mounted for measurement on the goniometer, the faces of the perovskite crystals described in the preceding paper yield, owing to the complex lamellated structure, a confused mass of images of the signal which cannot be analysed by the ordinary methods (such as using a lens in front of the eyepiece or shading portions of the face with a screen held in the hand), on account of the number and extremely small size of the reflecting surfaces. The apparatus described below was designed to give the means of identifying with certainty the image reflected from any given portion of such a face, and has been found to answer this purpose satisfactorily.
On the identity of Poonahlite with Mesolite
Authors: Bowman H. L.
Published: December 2006

Among the zeolite specimens from the neighbourhood of Bombay in the Oxford University Collection are several of the well-known type, showing pale green crystals of apophyllite associated with white stilbite and white silky needles labelled as ‘poonahlite’, on a matrix of purplish-brown amygdaloid, with a layer of a bluish-green, earthy mineral lining the amygdules and underlying the zeolites.

The name poonahlite was originally given by H. J. Brooke, in 1831, to a mineral occurring on specimens which he had received from Henry Heuland. He states that the poonahlite formed slender crystals accompanying apophyllite from Poonah, and was at first taken for mesotype or needlestone, but that it had a prism-angle of 92° 20′.
On the identity of Guarinite and Hiortdahlite
Authors: Zambonini F. , Prior G. T.
Published: December 2006

Although more than fifty years have passed since Guiscardi published the first description of guarinite, the true nature of this mineral has never yet been ascertained. As regards the crystalline form, Guiscardi's first idea was that the crystals of guarinite are orthorhombic (he had himself reckoned the ratio a : b = 0.9896 : 1 ; see literature, nos. 3 and 5); but, having observed crystals with a tetragonal habit, he finally decided to describe the mineral as tetragonal-hemihedral. V. v. Lang by his optical investigations appeared to place the orthorhombic symmetry of guarinite beyond doubt, and Des Cloizeaux later published a note on a combination observed by him.
A camera lucida attachment for the goniometer
Authors: Herbert Smith G. F.
Published: December 2006

When investigating the morphology of crystals, such as those of schwartzembergite, which are so rounded or striated as to afford no definite reflections of the object-slit of the goniometer, the author found most serviceable a camera lucida which could be attached to the eye-piece of the telescope of the goniometer, and thus used for the direct drawing upon paper of the ‘light-figures’ given by the crystals, the ordinary signal being replaced by a pin-hole. The cap of the eye-piece in use is unscrewed and the camera lucida is fixed to the tube by means of four clamping screws.
A new meteoric iron found near Kyancutta, South Australia
Authors: Spencer L. J.
Published: December 2006

The local interest aroused by the discovery in 1931 of the meteorite craters near Henbury in Central Australia has led to the finding of a new meteoric iron in South Australia. This is due to the energy and enthusiasm displayed by Mr. R. Bedford of the Kyancutta Museum. According to his letter dated August 23, 1932, the mass was found in June 1932 by a farmer, Mr. L. G. Gardiner, whilst cultivating a sandy paddock 28 miles ESE. of Kyancutta. It was turned up from just beneath the surface. He describes it as weighing 72 lb., and being 17 inches long and roughly triangular in section with a thickness of about 8 inches. The mass is weathered and one face shows four Sharply cut hemispherical pits (fig. 2) averaging 1¼ inches in diameter and 1 inch in depth. The main mass is now in the Kyancutta Museum.
Studies on the zeolites. Part VI. Edingtonite
Authors: Hey Max H.
Published: December 2006

The very rare barium zeolite edingtonite was described by W. Haidinger (1825), and named in honour of Mr. Ed.ington. Haidinger's material consisted of small crystals on thomsonite from Dumbartonshire. An analysis by E. Turner indicated a calcium aluminosilicate, but there was a loss of 11·22 %. The crystals (sp. gr. 2·71) were morphologically tetragonal, with the prism m(ll0) and sphenoids p(111) and n, and an axial ratio c/a = 0·6725. A. Breithaupt (1832) gave the name 'Antiëdrit' on account of this Symmetry,
Studies on the zeolites. Part VII. ‘Clinoptilolite’, a silica-rich variety of heulandite.
Authors: Hey Max H. , Bannister F. A.
Published: December 2006

In 1890, L. V. Pirsson 2 described under the name of mordenite a crystalline mineral, isomorphous with heulandite, occurring in a highly weathered amygdaloidal basalt in the Hoodoo Mts., Wyoming. His analysis (1, table I) showed that the mineral had a composition near that of the original mordenite of H. How (1864) and his assumption that it represented a platy-crystalline phase of that normally fibrous mineral was generally accepted.
Some unusual alkali-felspars in the Central Australian charnockitic rocks
Authors: Wilson Allan F.
Published: December 2006

During a universal stage investigation of the pegmatitic felspars in the Central Australian charnockites, several alkali-felspars were found which, according to the stereograrms published by Emmons (3, pl. 12), should have been near ' anorthoclase' in composition. This identification, based purely on optical properties, was questioned in the first instance because of the absence of other evidence for a soda-rich suite of minerals in these apparently potassic pegmatites. Two felspars which suggested a high soda-content were chemically analysed. Neither proved to be notably high in soda.
An X-Ray study of schultenite
Authors: Claringbull G. F.
Published: December 2006

In 1926 schultenite from Tsumeb, Otavi, South-West Africa, was described as a new mineral by L. J. Spencer and related to the compound PbHAsO4. The specimen on which the original description was based is still unique in the British Museum collection and was used for the present study. There appears to be no record in the literature that the mineral has been discovered in any other locality

For the X-ray examination rather small fragments (less than 0·1 × 0·05 mm.) were broken from pieces of crystals since all the available crystals were too large and the material has a high absorption to X-rays. Single crystal rotation, oscillation, and Weissenberg photographs in 6-cm. diameter cameras with Cu-Kα radiation as well as Laue photographs (crystal-plate distance 4 cm.) with tungsten radiation were used to derive the unit-cell dimensions and space-group.
The uranium deposits of the Tete District, Mozambique
Authors: Davidson C. F. , Bennett J. A. E.
Published: December 2006

Early in 1947 an unusual mineral deposit was discovered at Mavuzi in the Tete district of Mozambique. The discovery was made by native boys searching for corundum on behalf of Senhor Mario Canuto de Carvalho, a Goanese prospector who had for some years been associated with primitive gold and corundum operations on the north bank of the Zambesi. The dominant ore-mineral in the new deposit was superficially similar to the pegmatitic samarskite found in small quantities in the mica-mining districts of the Alto Ligonha in eastern Mozambique; and when exposure of the mineral to a photographic plate confirmed that it was radioactive, the identification as samarskite was accepted both by local prospectors and by most of the field geologists who later worked on the deposits. The presence of uranium in the ore was first proven in a chemical analysis by the Southern Rhodesian Geological Survey.
The riebeckite-bearing dikes of Shetland (With Plate III)
Authors: Phemister James , Harvey C. O. , Sabine P. A.
Published: December 2006

The peninsula in which the mainland of Shetland ends north of Ronas Voe and Colla Firth is occupied mainly by the Ronas Hill Granite. This body is intrusive into a metamorphic series consisting of orthogneiss on the north and paragneiss oil the north-east, east, and south-east of tile peninsula. It is a biotite-granophyre within which earlier bodies of basic rock varying from diorite to gabbro are found. It is unsheared and unfoliated and is cut by a swarm of dikes with north-south trend which extends from tile north coast to Ronas Voe. There is evidence also of the existence of dikes earlier than the granite. The later dikes comprise spessartine, microdiorite, porphyrite, quartzfelspar- porphyry, and a great variety of felsites which are generally granophyric and spherulitic. Many of the felsites contain riebeckite and aegirine and have a corresponding blue or blue-green colour. From observation of chilling of dike against dike and intersection of dike by dike it has been found that tile basic dikes, spessartine, microdiorite, and porphyrite, are the oldest of the suite, the quartz-felspar-porphyries are older than the felsites, and the blue riebeckite-felsites are younger than white, pink, and dull red felsites which contain neither aegirine nor riebeckite
John Henry Heuland
Authors: Russell Arthur
Published: December 2006

John Henry Heuland, Fellow of the Geological Society, mineral collector and dealer of 25 King Street, St. James's, London, was born in 1778. He moved in 1839 to 31 Red Lion Square, London, where he remained until after 1850. Few details of his life are known, but his sale catalogues and his intense activity as a collector and dealer during the period when it was fashionable to form collections of minerals have secured him an important place in the historical archives of mineralogy.

In what year Heuland began to deal in minerals is uncertain, but it was before 1804 when we have a record of his buying in Lisbon. He subsequently travelled through France, Germany, Sweden, and Russia, collecting and buying minerals wherever possible. About the year 1806 he came into the possession of a fine collection of nfinerals which had been formed on the Continent between the years 1766 and 1806 by his uncle Mr. Jacob Forster.
On crossite from Anglesey
Authors: Holgate Norman
Published: December 2006

The occurrence of a member of the glaucophane group of minerals in Anglesey has been known since 1888, in which year Blake reported the presence of a blue amphibole in a schist exposed in the neighbourhood of the Anglesey Column, west of the Menai Bridge. In the course of his paper Blake made general remarks on the petrography of the schist and on its field relations. He dwelt at some length on the question of the identity of the blue amphibole which is its most notable constituent, describing its columnar habit and pleochroism, and recording an extinction angle of 15° with the axis of elongation (c). By comparison with a description of glaucophane due to Rosenbusch, Blake concluded that the blue amphibole from the Anglesey rock is a normal glaucophane, although it, an extinction angle as recorded by him is considerably in excess of the 4° to 6° mentioned by Rosenbusch.
Sinhalite (MgAlB04), a new mineral. (With Plate XXVII)
Authors: Claringbull G. F. , Hey Max H.
Published: December 2006

The investigation which has led to this description of a new mineral began because of a suggestion by Dr. W. F. Foshag, when on a Visit in 1951 to the Mineral Gallery of the British Museum (Natural History), that a brown cut gemstone exhibited as olivine had perhaps been incorrectly determined. More recently, Dr. Foshag has stated that the idea came from Dr. George Switzer, who as a result of an X-ray powder photograph taken in June 1950 of a similar specimen in the collection of the United States National Museum in Washington concluded that his material was not olivine and was likely to be a new species. The present work would not have been pursued had it been realized at the time that Dr. Switzer intended to continue the study when he had suitable material for analysis.
Manganese-iron garnet from Otjosondu, South-West Africa
Authors: Vermaas F. H. S.
Published: December 2006

Garnets rich in manganese and iron, associated with bariumfelspars, have been reported by de Villiers from the manganese ores of Otjosondu, South-West Africa, in which they occur as the most abundant silicate mineral. The farm Otjosondu is 80 miles NE. of Okahandja, a railway station on the line between Windhoek and Walvis.

One specimen (referred to as no. 1), of which de Villiers published a chemical analysis, is massive and of a somewhat dark-yellowish colour. The material is traversed by veinlets of hyalophane (Cn9), about 0.5 mm. broad.
The structures of the plagioclase felspars: VI. Natural intermediate plagioclases
Authors: Gay P.
Published: December 2006

Specimens from some forty different localities over the composition range from about 20 % An to about 70 % An have been examined by X-ray single-crystal methods. The majority of these specimens show the normal intermediate plagioclase pattern characterized by weak pairs of subsidiary layer-lines of variable separation. It has been found that the separation of these layer-lines is a linear function of composition over the whole composition range. Further, this range is found to extend to more soda-rich compositions than was formerly believed, whilst the limits of the range are approximately defined by the compositions at which the separations of the subsidiary layer-lines about either thea- or theb-axes become zero.

The anomalous patterns shown by some specimens are discussed, and it is shown that most of these may be interpreted in terms of the previous geological history of the specimens.

A comparison of the present results with those obtained by previous workers in this field is made, and it is shown how the principal points of difference may be resolved. An account of the phase relationships of the low-temperature plagioclase series is given, and the problems arising from the present work are discussed.
The section CaSiO3-MgSiO3-Al2O3
Authors: Segnit E. R.
Published: December 2006

Phase relationships in the section CaSiO3-MgSiO3-Al2O3 through the quaternary system CaO-MgO-Al2O3-SiO2 have been determined. The bearing of the results on the genesis of aluminous pyroxenes and associated minerals in metamorphic rocks is discussed.
Some new occurrences of gonnardite
Authors: Meixner H. , Hey M. H. , Moss A. A.
Published: December 2006

This zeolite, hitherto recorded only from Chaux de Bergonne, France, has been found as zoned spherules with thomsonite (var. faroelite), on specimens from Aci Castello and Aci Trezza, Sicily, and Capo di Bove, Rome, from Weilberg, Rhineland, and from Klöch, Styria. Three chemical analyses confirm previous results; optical data suggest some variation in composition within a spherule. There is a striking resemblance between X-ray fibre photographs of gonnardite and of thomsonite, and between X-ray powder photographs of gonnardire and of natrolite. The Klöch occurrence, where the gonnardite is accompanied by phillipsite, is described in detail.
An effect of depth of focus on micrometric analysis
Authors: Elliott R. B.
Published: December 2006

When using many patterns of integrating stage the depth of focus is so great that it is not possible to distinguish between the upper and lower surfaces of a thin section; this may introduce serious errors into micrometric analyses. A procedure to meet this difficulty is suggested.
An unusual cassiterite paragenesis and its genetic implications
Authors: Lawrence L. J.
Published: December 2006

In the Torrington district of New South Wales the cassiterite occurs almost entirely in hydrothermal veins, with galena, blende, quartz, and chlorite; sometimes it replaces crinoid stems and gastropods. In the Madman vein, however, the cassiterite is associated with adularia, both minerals encrusting quartz. These observations suggest that the tin came in as alkali stannate solutions.
The system diopside-anorthite—åkermanite
Authors: Christiaan De Wys E. , Foster Wilfrid R.
Published: December 2006

The high-temperature phase equilibrium relationships in the system diopside-anorthite—åkermanite have been investigated by the quenching method. This system may be regarded as essentially a simple eutectic system. The eutectic is located at the composition 9 diopside:44 anorthite:47 åkermanite (by weight) and at a temperature of 1226° C. Åkermanite is a stable phase at least as low as this temperature. Triclinic anorthite is the only form of CaAl2Si2O8 encountered in the liquidus range of temperatures.
Bonchevite, PbBi4S7, a new mineral
Authors: Kostov Ivan
Published: December 2006

In quartz-seheelite veins traversing rocks from the metamorphic complex in the Central Rhodopian mountains, a mineral was found closely resembling bismuthinite. Its composition is Bi 66·62 %, Pb15·50 %, Cu 0·85 %, and S 16·71 %, corresponding to the formula PbBi4S7. It is orthorhombic, long prismatic to acicular with an axial ratioa:b:c= 0·9004:1:0·3249. Observed forms: {110}, {100}, {010}, and {011}. Sp. gr. 6·92. Hardness about 2 1/2. Displays a perfect cleavage along {100}. It is distinctly anisotropic. Strongest X-ray intensities: 3·50 Å. (10), 3·08 (8), 1·939 (8), 2·78 (6), 1·733 (6), 2·50 (5). The name is after the eminent Bulgarian mineralogist and petrographer G. Bonchev.
New techniques for the universal stage. II. The determination of the 2V when only one optic axis is accessible
Authors: Joel N. , Muir I. D.
Published: December 2006

When one optic axis of a biaxial crystal has been located accurately by the usual orthoseopic or conoscopic methods, the second may be located by determining the extinction positions at normal incidence and applying the Biot-Fresnel construction. When use is made of the extinction directions associated with two or more wave normals inclined to the section, this method gives more reliable values of the optic axial angle than can be obtained by the doubling of the angle V over the pole of a bisectrix. If the optic axes have been located with sufficient accuracy by this procedure, then this also determines the orientation of the indicatrix.
The effect of composition and structural state on the rhombic section and pericline twins of plagioclase felspars
Authors: Smith J. V.
Published: December 2006

The position of the rhombic section of plagioclase felspars, as calculated from the measured cell dimensions, has been shown to vary with the structural state, the variation from high- to low-temperature forms being most pronounced for albite. The theoretical composition plane of pericline twins is the rhombic section. If the structural state or the composition of the felspar changes after twinning has occurred, the cell dimensions and hence the rhombic section will change; however, the composition plane of the pericline twin will probably remain unchanged unless recrystallization occurs, or perhaps if the felspar is subjected to strong stress. Thus the observed pericline composition plane need not coincide with the rhombic section. Comparison of observed composition planes with the corresponding calculated rhombie sections shows that some of them do indeed differ and the differences have been used to provide information on the changes occurring subsequent to the establishment of the pericline twins. The interpretation is complicated by the occurrence of the acline-A twin, whose composition plane is {001}, for the rhombie section of plagioclase felspars from An0to An60may coincide with {001} if the structural state of inversion has a particular value. When the observed composition would agree with both pericline and acline-A twinning, the new termb-axis twinhas been used.
Variation of refractive index with ionization potential in some isostructural crystals
Authors: Ahrens L. H.
Published: December 2006

A closer understanding of the causes for the variation of refractive index with change of composition has been sought in terms of certain properties of ions. The study is confined to isostructural ionic crystals. It is assumed that polarization of the anions (usually O2− or F−) makes the principal contribution to the total refractive index effect, and that variation of refractive index is determined mainly by variable anion polarization. Polarization of the anion is controlled largely by the field in which it finds itself which, in turn, depends on the effective force of attraction of the cation: ionization potentials are used for the purpose of comparing such forces. For compounds involving pairs of 8- and 18-electron cations (Mg2+ and Zn2+; Al3+ and Ga3+; Si4+ and Ge4+; Ca2+ and Cd2+) or pairs of transition cations (Zr4+ and Hf4+; Nb5+ and Ta5+; Mo6+ and W6+) refractive indices are higher in the crystal that contains the cation of the element with the higher ionization potential. For larger suites of cations of various types (for example, Mg2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+, radii from 0·65 to 0·80 Å.) the predicted relationship between ionization potential and refractive index holds precisely for the compounds A2SiF6.6H2O (A2+, etc.), but only in part for other compounds; this may be due to the effect of the crystal field on certain 3d transition cations.
Helvine from a lithium pegmatite near Salisbury, Southern Rhodesia
Authors: von Knorring O.
Published: December 2006

A new occurrence of helvine, the rare manganese end-member of the helvine group, is described. The mineral is found in a granite pegmatite associated with microcline-perthite, petalite, spodumene, muscovite, and spessartine. A chemical analysis of the mineral is given.
The amygdale minerals in the Tertiary lavas of Ireland. II. The distribution of gmelinite
Authors: Walker George P. L.
Published: December 2006

Mapping of the distribution of zeolites in the Antrinl basalku has revealed that gmelinite is confined to a narrow zone along the eastern seaboard of Antrim. This zone comprises less than 1% of the area of the basalts, but in it gmelinite is extremely abundant. The gmelinite zone is superimposed upon the lava pile, and the minerals in it are clearly later than the laves; it is in the form of a dome, elongated north-west and traceable for 18 or 24 miles in this direction, and is found in the basal parts of the lava pile, locally reaching a height of some 500 feet in the pile. The zone may be related in its position and origin to the Island-magee fault zone. Gmelinite frequently forms a parallel overgrowth on chabazite. Superimposed upon the southern part of the gmclinite zone is a zone of late chabazite and heulandite containing, inter alia, parallel overgrowths of late chabazite on simple or twinned gmelinite.
A note on pyrosmalite from Nant Francon, North Wales
Authors: Brown P. E.
Published: December 2006

The presence of pyrosmalite is recorded in a metasomatized slate that is in contact with intrusive rhyolite in the Nant Francon area of North Wales.
A dickite with an elongated crystal habit and its dehydroxylation
Authors: Schmidt E. R. , Heckroodt R. O.
Published: December 2006

Dickite from a new occurrence at Barkly East, Cape Province, is described and compared with a previously unreported dickite from Postmasburg and a dickite from Ouray, Colorado. The Barkly East dickite crystals are elongated in the direction of the a-axis; the ratio of length to width of crystals varies from 3:1 to 16:1. Optical, electron microscopic, X-ray, and thermal data and a chemical analysis are given. The thermogram of the fraction smaller than 2 µ e.s.d.1 is characterized by a single peak at 600°C., while that of fractions larger than 2 µ e.s.d. shows a double endothermal effect. This two-stage dehydroxylation of dickite on heating is attributed to a particle size effect.
The transformation of tobermorite into xonotlite
Authors: Taylor H. F. W.
Published: December 2006

This hydrothermal process has been studied using single crystal X-ray methods. A crystal of tobermorite (Ca5Si6O22H10), treated with water at 380° C. and 250 atmospheres, gives a preferred orientation aggregate ofxonotlite (Ca6Si6O17(OH)2), together probably with unoriented silica. The relationship of orientations of product and starting material was established. The change occurs without intermediate dehydration of the tobermorite to the 9·35Å. state. The structural basis of the relationship is discussed, and it is compared with those already reported for the transformations of tobermorite into β-CaSiO3 and of xonotlite into β-CaSiO3. A simple experimental procedure for the single-crystal study of hydrothermal reactions is described.
What is plinthite?
Authors: Sweet Jessie M.
Published: December 2006

Many specimens of plinthite, a species described from Co. Antrim by T. Thomson in 1836 and later from Skye by M. F. Heddle, prove to be mixtures of zeolites and hematite. Both original analyses are those of a ferruginous clay (a mixture of hematite, kaolinite, and montmorillonite). The type specimen (Thomson Collection) is a red clay in the montmorillonite group intimately mixed with hematite and a little analcime.
The Tomhannock Creek, New York, chondrite
Authors: Mason Brian , Wiik H. B.
Published: December 2006

The Tomhannock Creek chondrite has been analysed, with the following results: Fe 11·36, Ni 1·69, Co 0·07, FeS 5·26, SiO2 36·88, TiO2 0·135, Al2O3 1·80, Cr2O2 0·30, FeO 14·94, MnO 0·31, MgO 23·81, CaO 1·39, Na2O 0·73, K2O 0·095, P2O5 0·36, H2O+ 0·34, C 0·10; total 99·57. The mineralogical composition is olivine (Fo81), hypersthene (En83), plagioclase (An22), nickel-iron, troilite, chromite, and probably apatite. The density of the meteorite is 3·65.

Tomhannock Creek is not identical with Homestead, nor with Yorktown. Yorktown is a chondrite that appears to have fallen near Yorktown, Westchester County, New York (41° 17′ N., 73° 49′ W.), in September 1869.
A thermodynamic analysis of the system anorthite-åkermanite
Authors: de Wys E. Christiaan
Published: December 2006

From thermodynamic considerations of the system anorthite-åkermanite it appears that the melts in this system are ionic in nature. The liquidus relation in this system would thus seem to afford confirmation of the theory, based on conductivity measurements, that silicate melts such as molten anorthite dissociate into such ions as Ca2+ and (Al2Si2O8)2−.

Further thermodynamic calculations involving no unreasonable assumption lead to a close reproduction of the experimental liquidus curve of åkermanite. This lends added strength to the belief in the stable existence of åkermanite down to the eutectic; no evidence in support of the claim that åkermanes becomes unstable below 1 325° C. (Osborn and Schairer, 1941) was encountered.

According to Osborn et al. (1954) the presence of substantial Ca2+ increases the desulphurizing potential of blast furnace slag. The thermodynamic treatment of the binary system anorthite-åkermanite leads to the conclusion that both phases dissociate in the molten state and in mutual solution to yield Ca2+; it therefore appears probable that a high concentration of these minerals in the slag would have a salutary effect on the slag chemistry.
Amphibolite-granulite facies assemblages in southern Nyasaland
Authors: Morel S. W.
Published: December 2006

The mineral assemblages developed in a variety of high-grade metamorphic rocks from southern Nyasaland are compared with standard metamorphic facies mineral assemblages proposed by some authors.
On the lithium amphibole holmquistite, from Benson pegmatite mine, Mtoko, Southern Rhodesia
Authors: von Knorring O. , Hornung G.
Published: December 2006

A new occurrence of holmquistite is described. The mineral is found in amphibolite at the contact of a lithium pegmatite. Chemical analyses and optical data of the holmquistite and an associated hornblende are given.
Methods for the chemical analysis of meteorites. I. Siderites
Authors: Moss A. A. , Hey M. H. , Bothwell D. I.
Published: December 2006

Simple chemical procedures (colorimetric and gravimetric) for the determination of Co, Cr, Cu, Ga, Ni, P, and S in an iron meteorite or in the separated metallic phase of a pallasite are described; the minimum size of sample is discussed. A procedure for the quantitative removal of the metallic, sulphide, and phosphide phases from a stone or siderolite is described, and is applicable to the quantitative isolation of silicate and oxide inclusions from siderites (other than some very high in nickel).
Twenty-second list of new mineral names
Authors: Hey M. H.
Published: December 2006

This list continues the series of 21 published triennially by Dr. L. J. Spencer between 1897 and 1958. Such lists evidently meet a generally-felt need, as they now appear in the American Mineralogist, the Bulletin de la Société française de Minérlogie et de Cristallographie, and the the continuation of Dr. Spencer's series seems desirable since it differs from the others in several respects.
Heyite, Pb5Fe2(VO4)2O4 , a New Mineral from Nevada
Authors: Williams Sidney A.
Published: December 2006

Heyite occurs in silicified limestone with other oxidation-zone minerals derived from galena, chalcopyrite, and pyrite. The occurrence is near Ely, Nevada. Most common are pyromorphite, cerussite, and chrysocolla. Heyite occurs on and replaces corroded tungstenian wulfenite. Crystals are small (up to 0·4 mm), simple in habit, and monoclinic. Only {001}, {100}, {110}, and {01} have been observed. Twinning on {110} is relatively common. The colour is yellow-orange with a yellow streak, H = 4. Electron probe analyses (average of three) gave PbO 75·4 %, ZnO 0·81 %, FeO 8·41 %, V2O5 12·65 %. This leads to Pb5(Fe,Zn)2(VO4)2O4, with Z = 1.

The space group is P21/m. Cell constants, refined from powder data, are a 8·910 Å, b 6·017, c 7·734 (all ±0·004 Å); β III° 53′±4′. The strongest powder lines (Cr-Kα) are: 3·248, 11, (100); 2·970, 30, 21 (69); 2·767, 211 (61); 4·873,110, (46); 3·674, 111, (35); 2·306 (33); 3·010, 020, (29); 3·412, 20, 11, (25); 8·281, 100, (25); and 2·113 (20). Gcalc 6·284, Gmeas 6·3±0·2 Optically biaxial with 2Vγ 82°calc, 89°meas; αD 2·185, βD 2·219, γD 2·266; all values ±0·01 and determined in S-Se melts. Dispersion is weak with π > ν. The orientation is β = b, α: [001] 36° (in obtuse β). Nonpleochroic.

Three small specimens were found, and represent a total of less than 100 mg of the mineral. One has been deposited with the British Museum (Natural History). The name is for Dr. Max Hey, eminent British chemist and mineralogist.

The cell is strikingly similar to that of brackebuschite but electron probe examination of a newly analysed (by atomic absorption) specimen of the latter from the type locality in Argentina shows a marked chemical difference. Heyite strongly resembles descloizite in appearance.
Ortho- and Clino-Pyroxenes from the Charnockite Series of Amaravathi, Andhra Pradesh, South India
Authors: Ramaswamy A. , Murty M. S.
Published: December 2006

The chemical analyses, structural formulae, and optical data of seven orthopyroxenes and six clinopyroxenes, all from the charnockite series of Amaravathi, are presented. The orthopyroxenes are in the hypersthene-ferrohypersthene range while the clinopyroxenes are in the sahlite range. The aluminous nature of the pyroxene is believed to be the result of high pressure. The clinopyroxenes have the granulite trend on the Wo-En-Fs plot. The tie-line projections and the KD values for the pyroxene pairs indicate conditions of chemical equilibrium around 670 °C for the charnockite series of Amaravathi.
The development of crystalline structure in aluminium hydroxide polymorphs on ageing
Authors: Elderfield H. , Hem J. D.
Published: December 2006

Infrared absorption spectra of the precipitated solids separated from aluminium-hydroxide solutions below the pH of minimum solubility of Al(OH)3 demonstrate the slow ageing of polymeric Al complexes to gibbsite. On comparison with the spectra of natural gibbsites, shifts in absorption frequency during crystal growth are interpreted in terms of changes in hydrogen bonding as a consequence of deprotonation and stacking of aluminium hydroxide layers to form gibbsite. In alkaline solutions the bayerite polymorph precipitates and IR frequencies are compatible with protonation as aluminate ions associate with the bayerite crystal having a lower crystal energy than its low pH polymorph. The infrared spectrum of nordstrandite, which is probably the stable polymorph in alkaline solution, shows evidence of strongly polarized hydroxyl ions similar to gibbsite.
Composition of chromites in cordierite-and mica-bearing Cr-Ni ores from Málaga Province, Spain
Authors: Oen I. S. , Kieft C. , Westerhof A. B.
Published: December 2006

An unusual paragenesis of chromite, nickeline, cordierite, and red-brown mica occurs in veins, pods, and schlieren in serpentinized ultramafic rocks at La Gallega and Los Jarales in Máilaga province, Spain. The chromites in this paragenesis are low-ferric, ferrous-rich aluminous chromites with exceptionally high vanadium content ranging between 1·8 and 2·9 wt % V2O3and high zinc content ranging between 0·5 and 1·0 wt % ZnO. A comparison of chromite composition with available experimental data, together with paragenetical and textural evidence, suggests that the chromite, cordierite, and red-brown mica crystallized at magmatic temperatures between approximately 1300° and 1000°C at low oxygen fugacities and maximum pressures below 10 kb, probably near 5 kb.
The Kabo, Nigeria, meteorite fall
Authors: Hutchison R. , Ajakaiye D. E. , Elliott C. J. , Fry F. A.
Published: December 2006

At least four stones fell over a distance of about 9 km at the end of a west to east trajectory on 25 April 1971 at about 1630 hours local time. Their approximate location is 11° 51′ N., 8° 13′ E. About 13·4 kg of this xenolithic bronzite chondrite, class H4, were recovered. A bulk chemical analysis with total Fe = 29°4 % (wt), is presented. Olivine is Fa18.9 (molec.) in composition. Concentrations of the cosmogenic radionuclides 22Na, 26Al, and 54Mn were 71±6, 56±5 and 84±6 dpm/kg, respectively.
Crystal structures of some double hydroxide
minerals
Authors: Taylor H. F. W.
Published: December 2006

Three groups of minerals are discussed,
which are typified by pyroaurite and sjögrenitc,
hydrocalumite, and ettringite. All show
interesting structural features. In the
pyroaurite-sjögrenite group, brucite-likc layers
carrying a net positive charge alternate with
layers in which the oxygen atoms of carbonate
groups and water molecules are statistically
distributed on a single set of sites; other anions
may replace the carbonate, especially in synthetic
phases. Hydrocalumite and related synthetic phases
also have layer structures in which positively
charged main layers alternate with intermediate
layers containing anions and water molecules; the
anions occur in cavities and their nature can
again vary widely. In the ettringite group, the
structures are based on positively charged
columns, between which occur channels containing
anions and sometimes also water molecules. This
group includes thaumasite, the only natural
mineral known to contain silicon six-coordinated
by oxygen that is not a high-pressure phase. The
thermal dehydration behaviour in each group is
briefly considered.
The crystal chemistry of the amphiboles II Refinement of the crystal structure of oxy-kaersutite
Authors: Hawthorne F. C. , Grundy H. D.
Published: December 2006

Three-dimensional counter-diffractometer data corrected for absorption and a full matrix least-squares method have been used to refine the crystal structure of an oxy-kaersutite in the space groupC2/m. The chemical composition of the amphibole is with cell parametersa9·8920(11),b18·064(2),c5·3116(7)Å and β 105·388(5)°. Cation site occupancies were refined using bulk chemical constraints and the A-site positionally disordered. The final conventionalR-factor for 1041 observed reflections is 4·0%.

The rotation of the tetrahedral chains in calcic clino-amphiboles is shown to be a function of the Alivcontent of the tetrahedral sites. Comparison of this oxidized amphibole with an hydroxyamphibole of similar chemical composition indicates that on oxidation the maximum amount of structural relaxation takes place in the vicinity of theM(I) octahedra, which distort to a high-energy configuration.
Hydrothermal synthesis of albite: the
effect of NaOH on Obliquity
Authors: Trembath L. T.
Published: December 2006

A series of albites was synthesized in the
presence of aqueous NaOH fluids (concentration 0
to 4N NaOH,
Pfluid
= 15000 1b/in2) over the
temperature range 300 to 500 °C. At fixed
temperature-pressure conditions increasing NaOH
concentration of the initial fluid can be
correlated with decreasing obliquity of the
albites.
Conjugate cummingtonite and hornblende at
Sgeir nan Sgarbh, South Harris, Outer
Hebrides
Authors: Livingstone A. , Frost M. T. , Suddaby P.
Published: December 2006

Chemical analyses, cell parameters, and
optical data are presented for conjugate
cummingtonite and hornblende, which occur in a
paragneiss. A metasomatic origin for the
development of hornblende from cummingtonite,
during retrogressive metamorphism, is
proposed.
Crystallization trend of titanomagnetites
in an alkali basalt from Saint-Clément (Massif
Central, France)
Authors: Prévot M. , Mergoil J.
Published: December 2006

Three generations of homogeneous
titanomagnetite in a hawaiite from Saint-Clément
may be defined by differences in size, habit, or
reflectance, and are believed to correspond to
different crystallization stages of the lava.
Chemical compositions were determined by electron
microprobe, and by X-ray and thermomagnetic
methods.

Larger crystals are of intratelluric
origin and occur either as inclusions in
phenocrysts of early clinopyroxene (generation 1)
or separately in the groundmass (generation 2); in
the latter case, they always show evidence of
resorption. Post-eruptive titanomagnetite
(generation 3) is smaller and so highly oxidized
that it is better termed titanomaghemite. Since
the maghemitization, which is a low temperature
process, alters the metallic ratios (especially
the Fe/Ti ratio) the metallic contents at the time
of the high-temperature crystallization are
exactly known only for the intratelluric
titanomagnetites.

As intratelluric crystallization proceeds
Ti content increases greatly (5 to 14%); Mn also
increases (but slightly), A1 and Mg decrease,
while results for Cr are inconclusive. Apparently
these changes go on until the post-eruptive
crystallization stage.

The titanium trend is contrary to common
belief. However, it is in accordance with
predictions from the Fe-Ti-O system and may be
explained by a decrease in oxygen fugacity during
magma ascent.
Nahcolite (NaHCO3) in inclusions in apatites from some E. African ijolites and carbonatites
Authors: Rankin A. H. , Le Bas M. J.
Published: December 2006

Nahcolite (NaHCO3) is identified and recorded for the first time from an igneous rock. Often associated with it is another carbonate mineral tentatively identified as kalicine (KHCO3), which has not previously been recorded as a primary mineral in any rock. These minerals occur in inclusions in apatite crystals in ijolites and carbonatites, and indicate that both ijolite and carbonatite magma must have been considerably richer in soda and potash than is indicated by the chemical analyses of the rocks. The identification was made by a combination of microchemical, solubility, crystallographic, and optical determinations.
Examples of twinning and parallel growth in zircons from some Precambrian granites and gneisses
Authors: Jocelyn J. , Pidgeon R. T.
Published: December 2006

Growth twins, parallel growths, and necked crystals are described from zircon populations from granitic gneisses from the Precambrian of SW. Greenland. From observations of the distribution of internal growth zones it is concluded that whereas twinning takes place early in the growth history of elbow twins it can occur at any time during crystallization of the zircon. Parallel growth is attributed to a process of synneusis or attachment of zircons that have initially undergone separate growth histories. This implies that viscosity conditions of the rocks were low enough to permit the movement and collision of growing zircon crystals. The common occurrence of zircons with central constrictions, sometimes superimposed on transverse fractures, in zircon suites from the granitic gneisses is explained in terms of late-stage chemical corrosion accompanied by brittle fracturing.
Phosphate minerals from Reaphook Hill, Flinders Ranges, South Australia
Authors: Hill R. J. , Milnes A. R.
Published: December 2006

Several uncommon phosphate minerals including tarbuttite, parahopeite, scholzite, and collinsite occur in near-surface gossans at the Reaphook Hill zinc prospect. Electron-probe microanalyses of the tarbuttite and scholzite compare well with published analyses of specimens of these minerals from the type localities in Zambia and Bavaria respectively. However, microanalyses of the parahopeite are significantly different from published analyses of parahopeite, and suggest that it may be one member of an isomorphous series in which six-coordinated Zn can be replaced by other cations, including Fe, Mg, and Mn. Furthermore, crystals of the Reaphook Hill parahopeite are compositionally zoned with their centres enriched in Fe and Mn relative to the margins, which are enriched in Mg.

Zincian collinsite occurs at Reaphook Hill as concentric crusts composed of very fine grained radially oriented plates. Electron-probe microanalyses of this material are significantly different from published analyses of collinsite from the type locality in British Columbia: Zn instead of Fe occupies the divalent cation sites; this material may be part of an isomorphous series that includes fairfieldite. Microanalyses also indicate that the Reaphook Hill collinsite crusts are compositionally zoned such that Zn:Mg ratios vary from the base to the outer edges of the crusts. This zoning is interpreted as the result of variation in the availability of Zn and Mg during growth. Zoning of similar type, but due to variation in the Fe: Mg ratio, was observed in concentric crusts of collinsite from the type locality in British Columbia.