R. E. Bevins

Aberystwyth University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Namuwite, (Zn,Cu)₄SO₄(OH)₆.4H₂O, a new mineral from Wales

Mineralogical Magazine (1982)

R. E. Bevins S. Turgoose Peter A. Williams

Abstract Found on a specimen in the mineral collection of the National Museum of Wales, no. NMW 27.111.GR414, from the Aberllyn mine, Llanrwst mining field, North Wales, with hydrozincite on a breccia cemented by sphalerite, quartz, calcite, and ankerite. Atomic absorption and TGA analyses gave ZnO 37.8, CuO 22.0, SO 3 14.9, H 2 O 24.5, total 99.2%, corresponding to (Zn 2.50 Cu 1.49 ) Σ3.99 S 1.00 O 7 ·7.32 H 2 O on the basis of total O = 7 in the anhydrous part. The ideal formula is (Zn,Cu) 4 SO 4 (OH) 6 ·4H 2 O where Zn > Cu. It is hexagonal a 8.29, c 10.50 ± 0.01 Å, possible space groups P 6, P , P 6/ m , P 622, P 6 mm , P m 2, P 2 m , and P 6/ mmm . Isomorphous with synthetic Zn,SO 4 (OH) 6 6·4H 2 O and (Zn,Cu) 4 SO 4 (OH) 6 ·4H 2 O. Strongest X-ray powder diffractions are: 10.59(100)0001, 5.31(15)0002, 4.15(25)11 0, 2.71(42)21 0, 2.63(41)21 1,0004, 2.41(22)21 2, 1.57(23)32 2, 1.55(20)41 1. Namuwite is pale sea-green in colour, lustre pearly, streak very pale green, H (Mohs) 2. Cleavage {0001}, perfect. Density (g/cm 3 ) 2.77 (meas.), 2.81 (calc. on the normalized empirical formula). It is optically uniaxial, sign not determined owing to the extremely low birefringence. Refractive index n = 1.577(5)(Na D ). The mineral and name have been approved by the Commission on New Minerals and Mineral Names, IMA.

Anhydrous

Structural formula

10.1180/minmag.1982.046.338.09

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Citations (24)

The Valle Nevado stratified sequence: chemistry and alteration pattern

Luis Aguirre Damian Robinson R. E. Bevins E. Fonseca Manuel Vergara

Sequence (biology)

Source

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Citations (2)

The link between fluids and rank variation in the South Wales Coalfield: evidence from fluid inclusions and stable isotopes

Geofluids (2004)

D. H. M. Alderton N. H. Oxtoby H. Brice Nathalie Grassineau R. E. Bevins

Abstract Fluid inclusion and stable isotope data from quartz and carbonate minerals in fracture fillings and ‘ironstone’ nodules from the South Wales Coalfield have been used to characterise the fluids generated during basin evolution and associated coalification. Carbonates grew first, probably at relatively shallow depths and low temperatures (<100°C). The carbonates exhibit a trend of increasing C‐isotopic values across the coalfield, ranging from δ 13 C = −12‰ VPDB in the SE of the coalfield to 0‰ VPDB in the NW, possibly as a result of increasing methanogenesis in the deeper (NW) parts of the coalfield. Quartz formed at a later stage of basin formation, probably at temperatures between 150 and 200°C. Fluid inclusions in these minerals suggest that burial and coalification of the sediments were associated with mixed aqueous–petroleum fluids. Furthermore, the density of these petroleum fluids decreases towards the NW of the coalfield, where the rank of the associated coal increases to anthracite grade. The study confirms that the composition and temperature of these fluids closely correlate with the variations in coal rank, indicating a possible causal link. The data also give general support to models that propose regional fluid flow in the basin. and are consistent with the erosion of approximately 2 km of section which is not preserved today. A geothermal gradient (at maximum burial) of 45°C km −1 is proposed, and thus no exceptionally anomalous thermal regime is required to explain coal rank variation.

Ironstone

Carbonate minerals

Anthracite

10.1111/j.1468-8123.2004.00083.x

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Citations (18)

U–Pb zircon-rutile dating of the Llangynog Inlier, Wales: constraints on an Ediacaran shallow marine fossil assemblage from East Avalonia

Figshare (2023)

Anthony J. I. Clarke Christopher L. Kirkland Latha R. Menon Daniel J. Condon John C. W. Cope

Appendix 1.

Assemblage (archaeology)

10.6084/m9.figshare.24745835

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Citations (0)

Diastathermal (extensional) metamorphism at very low grades and possible high grade analogues

Earth and Planetary Science Letters (1989)

D. Robinson R. E. Bevins

10.1016/0012-821x(89)90022-8

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Citations (32)

Retracing the footsteps of H.H. Thomas: a review of his Stonehenge bluestone provenancing study

Antiquity (2018)

R. E. Bevins Rob Ixer

Abstract

10.15184/aqy.2018.10

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Citations (4)

Zeolitization processes in basic lavas of the Báucarit Formation, northwestern Mexico

Andean geology (1994)

Jean Jacques Cochemé Luis Aguirre R. E. Bevins D. Robinson Philippe Münch

ABSTRACT. Basalts and basal tic andesites interbedded with sandstones in the molassic Baucarit Formation of northwestern Mexico show contrasting zeolite and clay assemblages in amygdales and in veins cross-cutting the flows. In amygdales, heulandite-clinoptilolite, chabazite, offretite/erionite and phillipsite are associated with a di-smectite clay. In veins, mesolite, analcime and stilbite are associated with minor clay, quartz and calcite. The low temperature nature of the zeolites and clays suggests that the infiltrating fluid had a temperature below 100°C and probably ca. 60°C. The absence of a pervasive alteration and a lack of correspondence between clay and host-rock chemistry suggest that this fluid was probably of a meteoric and fresh water character, which subsequently evolved into a more alkaline nature following interaction with glassy material in the interbedded mollassic sediments. RESUMEN. Procesos de ceolitizacion en lavas basicas de la Formacion Baucarit, noroeste de Mexico. Los basaltos y andesitas basalticas interestratificados con areniscas en la formacion molasica Baucarit del noroeste de Mexico poseen asociaciones contrastantes de ceolitas y minerales arcillosos contenidas en amigdalas y en venas que atraviesan las coladas. En las amigdalas, heulandita-clinoptilolita, chabacita, offretita/erionita y phillipsita estan asociadas con una diesmectita. En las venas, mesolita, analcita y estilbita se asocian con cuarzo, calcita y cantidades menores de minerales arcillosos. La ausencia de una alteracion pervasiva y la falta de correspondencia entre la composicion quimica de los minerales arcillosos y la roca huesped sugieren una precipitacion a partir de un fluido de origen externo. El caracter de baja temperatura de las ceolitas y minerales arcillosos sugiere que el fluido infiltrado tenia una temperatura inferior a 100°C y posiblemente cercana a 60°C. Este fluido era, probablemente, agua dulce de caracter meteorico que posteriormente evoluciono hacia una naturaleza mas alcalina a consecuencia de su interaccion con el material vitreo contenido en los sedimentos molasicos interestratificados.

Andesites

Analcime

Authigenic

10.5027/andgeov21n2-a05

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Citations (5)

Revisiting the provenance of the Stonehenge bluestones: Refining the provenance of the Group 2 non-spotted dolerites using rare earth element geochemistry

Journal of Archaeological Science Reports (2021)

R. E. Bevins Nicholas J.G. Pearce Rob Ixer

Outcrop

Rare-earth element

10.1016/j.jasrep.2021.103083

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Citations (12)

Fluid fluxes during low-temperature alteration: implications of multi-style alteration assemblages from the Welsh Borderland, UK

Geological Journal (1996)

Richard Metcalfe R. E. Bevins D. Robinson

Localized (domainal) low-temperature alteration may indicate variations in the chemistry of alteration fluids and/or discrete fluid flow paths during metamorphism. Occurrences of epidote- and pumpellyite-dominated domains are often used as evidence for large fluxes of Ca-rich fluids. However, comparative studies of two domainal alteration styles from basaltic to andesitic lavas and volcaniclastic rocks at Builth Wells, Wales, UK suggest that such interpretations cannot be applied universally. Here, only one set of domains can be attributed to large fluxes of Ca-rich fluids. In contrast, the second set of domains formed where the host rock supplied the necessary Ca, and fluid/rock ratios were relatively low. These domains are hosted by rocks which show a Caledonian regional metamorphic imprint, characterized by the alteration assemblage albite+chlorite+titanite±prehnite±pumpellyite±calcite±muscovite±quartz (considered to have formed at c. 200°C and ≤2.5 kbar). Type 1 domains lie along fluid channelways, such as veins. Pumpellyite is the dominant secondary mineral, but the alteration assemblage is variable with pumpellyite±prehnite±calcite±titanite±chlorite (±quartz). The domains formed at temperatures of 130–230°C during Ordovician hydrothermal activity, before the peak of regional metamorphism. In contrast, Type 2 domains are not associated with obvious fluid channelways. A central prehnite-dominated zone typically has a rim with the assemblage pumpellyite+calcite±prehnite±chlorite±titanite±K-rich phyllosilicate. These domains probably formed from pelitic xenoliths which contained a volcaniclastic component at temperatures of 130–230°C and at relatively low fluid/rock ratios. However, the timing of domain formation is uncertain. Pyrobitumen, in veins and disseminated throughout the rock, may have influenced the formation of both types of domain by stabilizing pumpellyite in preference to epidote and causing metamorphic calcite formation through the release of CO2 to the alteration fluids. © 1996 John Wiley & Sons, Ltd.

Titanite

Muscovite

Sericite

Phengite

10.1002/(sici)1099-1034(199612)31:4<323::aid-gj710>3.0.co;2-7

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Citations (2)

The Caledonian Rocks of Britain

Springer eBooks (1986)

R. E. Bevins W. Gibbons A. L. Harris Gilbert Kelling

Dalradian

Basement

Accretionary wedge

Orogeny

10.1007/978-94-009-4654-5_1

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Citations (4)