The Dhajala meteorite shower, the latest recorded fall in India, comprises pieces fragmented near the lower limit of the break-up zone. The meteorite is a chondrite consisting of silica-rich chondrules making up to 34 vol.%, and fine-grained, Fe-Ni metal-rich groundmass admixed with a few irregular lithic fragments. Dhajala contains olivine of variable compositions, ortho- and clinopyroxenes, troilite, kamacite, taenite, chromite, and clear to opaque glass; magnetite occurs only in the fusion crust. The chondrules, which are of variable shape, mineral composition, and texture, represent different stages of quenching, leading to incomplete crystallization of minerals and some degree of disparity between norm and mode. Lithophile elements are less in Dhajala than in average chondrites. Two chemical analyses of Dhajala are presented and it has 27·10% total iron and 2·38 % sulphur (maximum). Chemical and petrological data indicate that it is an H3 olivine-bronzite chondrite. Evidence for the crystallization of chondrules from melt is overwhelming. Some chondrules have been permeated by later troilite and NiFe from the groundmass, which might have crystallized directly from a gaseous environment.

Fassaitic diopside containing 22–23 wt% Al2O3 (approximately 41–43% calcium Tschermak's molecule, CaAl2SiO6) and melilite containing 69–43% gehlenite crystallized from a blast-furnace slag at atmospheric pressure between about 1450°C and 1250°C. The occurrence is of petrological interest because the association of pyroxene with gehlenite-rich melilite has not been recorded from experimental studies in the system CaO-MgO-Al2O3-SiO2, and because of the similarity of the compositions of both minerals to pyroxene and melilite in the Ca-Al-rich inclusions of the Allende meteorite.

Tritin(II)dihydroxyoxosulphate, Sn3O(OH)2SO4, is a rare corrosion product found on the surfaces of certain tin alloys. A new synthesis based on the hydrolysis of SnSO4 is described. The stability constant determination of Sn3O(OH)2SO4,s, at 298.2K and 105Pa is determined using direct measurements via electrodes, of the activities of tin(II) and sulphate ions. ΔfG0(298.2K) is equal to −1563.1 ± 0.9 KJ mol−1.

The pre-Caledonian NYF Skoddefjellet pegmatite in Wedel Jarlsberg Land, Svalbard, contains xenotime-(Y) that is partly replaced by fluorapatite-hingganite-(Y) reaction coronas. Hingganite-(Y) contains up to 2.0 wt.% of Gd2O3, 4.7 wt.% of Dy2O3, 3.3 wt.% of Er2O3 and 5.5 wt.% of Yb2O3. Such unusual, previously undescribed, xenotime-(Y) breakdown was caused by Ca- and F-bearing fluids interacting with the pegmatite. The occurrence of hinnganite-(Y) as a breakdown product of xenotime-(Y) implies that a Be-bearing phase (beryl in this case) was also involved in the reaction. There are few Ca-bearing primary phases in the pegmatite, indicating that the source of fluid was probably located in the generally Ca-richer host rocks (metasediments), though the fluid composition was modified during metasomatism of the pegmatite (i.e. beryl dissolution).

Tvrdýite, Fe2+Fe3+2A13(PO4)4(OH)5(OH2)4·2H2O, is a new phosphate mineral from the abandoned Huber open pit, in the Krásno ore district near Horní Slavkov, western Bohemia, Czech Republic. It was found along with Al-rich beraunite, fluorapatite and pharmacosiderite in a cavity of quartz gangue. Tvrdýite forms acicular to fibrous crystals with diameters in the range 0.5–5 μm and lengths up to 300 μm, partly grouped in radiating aggregates up to 3 mm in size. It has a silvery to olive, greyish green colour with pearly lustre, greyish-white streak and is very brittle with an uneven fracture; individual fibres are somewhat flexible. Cleavage on {100} is good; the Mohs hardness is ∼3–4. The calculated density is 2.834 g cm–3. Tvrdýite is optically biaxial (–), with α = 1.650(2), β = 1.671(1) and γ = 1.677(1) (white light); 2V = 56(1)°; dispersion: r > v, strong; optical orientation: Z = b, X ≈ a, Y ≈ c; pleochroism: X = greenish blue, Y = yellowish orange, Z = yellowish orange (X>> Y > Z). Tvrdýite is monoclinic, space group C2/c, a = 20.564(4), b = 5.101(1), c = 18.883(4) Å, β = 93.68(3)° and V = 1976.7(7) Å3, Z = 4, a:b:c= 4.031:1:3.702. The strongest eight lines in the powder X-ray diffraction (XRD) pattern [d in Å (I)(hkl)] are 10.227 (100) (200), 9.400 (6) (002), 7.156 (14) (202), 5.120 (7) (400), 3.416 (11) (600), 3.278 (6) (602), 2.562 (5) (800) and 2.0511 (3) (10,0,0). Chemical analyses by electron microprobe yielded MnO 0.01, ZnO 5.08, , FeO 4.31, Fe2O3 21.16, Al2O316.71, P2O5 32.64, As2O5 2.56, F 0.53, H2O (calc.) 17.84, O = F –0.22, total 100.62 wt.%. The resulting empirical formula, calculated on the base of 27 anions, obtained from the crystal structure, is Zn0.52Fe2+0.50Fe3+2.21Al2.75(PO4)3.86(AsO4)0.19OH4.60F0.23(OH2)4·2H2O. The ideal formula, Fe2+Fe3+2Al3(PO4)4(OH)5(OH2)4-2H2O, requires FeO 8.75, Fe2O3 19.44, Al2O3 18.62, P2O5 34.56, H2O 18.64, total 100.00 wt.%. The crystal structure of tvrdýite was solved from single-crystal data (synchrotron beamline) and refined to R1 = 0.038 for 2276 reflections with I > 2σ(I). Tvrdýite is isostructural with beraunite, but contains dominant Al in two of the four independent M sites, which are all occupied by Fe in beraunite.

The Krymka chondrite contains an exotic graphite-bearing fragment that appears to be of a new type of material added to unequilibrated LL-chondrite during agglomeration on the surface of the parent body. The fine-granular texture without chondrules, two morphological groups of graphite crystals which differ in size and occurence, high content of troilite (11.3 vol.%), the high Ni (55.5–66.6 wt.%) and Co (1.59–2.87 wt.%) contents of the taenite and absence of kamacite, the presence of F-apatite, which is rare for meteorites but common for lunar and terrestrial igneous rocks, are the main features of the fragment.

The mineralogy and texture indicate: (1) the fragment probably formed by crystallization from a highly reduced silicate melt, which had been enriched in carbon; 2) the subsequent metal sulphidization lowered its abundance and resulted in the formation of troilite and the compositional features of the residual metal; (3) terrestrial weathering of an exotic fragment and the host part of the chondrite produced iron hydroxides, pentlandite and quite possibly magnetite.

Ultramafic xenoliths enclosed in Plio-Quaternary alkali basalts from Tallante near Cartagne (southern Spain) are composed mainly of spinel lherzolites which are probably upper mantle residues. In many xenoliths, the spinel lherzolite is cut by pyroxenite or gabbroic anorthosite veinlets generally 0.2–3 cm thick. The clinopyroxenite veinlets were formed by high-pressure crystal-liquid segregation from alkali basalt magmas formed earlier than the host basalts, whereas mantle metasomatism played a role in the genesis of gabbroic anorthosites. Close to the contact with the veinlets, the spinel lherzolites are enriched in Ca, Fe, and some incompatible elements including light REE due to the migration of a fluid from the veinlets into the surrounding lherzolites. The host alkali basalts were derived from a heterogeneous, incompatible element-enriched upper-mantle source probably similar in composition and nature to the composite xenoliths, but were formed in a garnet stability field.

A borosilicate glass, containing 25 wt. % of simulated high-level radioactive waste has been reacted with water at 350°C and 500 bars for 14 and 48 days using large-volume ‘cold-seal’ high-pressure equipment. Under these conditions the glass crystallizes a suite of mineral phases including: albite, NaAlSi3O8; aegirine, NaFeSi2O6; riebeckite, Na2Fe2(Fe,Mg)3Si8O22(OH)2; zektzerite, LiNaZrSi6O15; barium-strontium molybdate, (Ba,Sr)MoO4; stillwellite, (Nd,Ce,La)BSiO5; willemite, Zn2SiO4; smectite; a lithium-sodium borosilicate hydrate; melilite (åkermanite), Ca2MgSi2O7. A description of the morphology of these phases is given, together with a number of chemical analyses. The implications of the incorporation of waste species in these mineral phases to the disposal of high-level radioactive waste is discussed.

There is an important corollary to Prior's rule to the effect that as the state of oxidation of meteorites is increased the quantity of olivine increases relative to pyroxene and metallic iron. We have derived a rigorous parametric expression for this corollary and find that, as in the case of the quantitative interpretation of the rule itself, there is in this case also a fair correspondence to the observational data, so that the validity of the rule is further supported.

The metamorphism surrounding the granite of Carn Chuinneag in eastern Ross-shire provides the classical example of polymetamorphism in which a regional metamorphism is superimposed on a normal thermal metamorphism.

Prior to the regional alteration a pelitic facies of the Moine sediments suffered metamorphism of a purely thermal type in the vicinity of the granite. At a subsequent date the whole region was involved in fold movements with the production of crystalline schists. In this deformation the belt of rocks surrounding the granite yielded in such a way that belts of the hornfels zone moved en masse and are preserved amidst rocks which are now typical crystalline schists, and all stages of transition between genuine hornfelses and typical micaschists can be traced in the field.

Although detailed experimental investigations have been carried out on the lime, magnesia, and ferrous pyroxenes, relatively little attention has been devoted to synthetic studies of the group involving replacements by ions of higher valencies. In the present study, determinations have been carried out on the limits of solid solution of alumina in pyroxenes in the system CaSiO3-MgSiO3-A12O3. Determinations of the solubility of ferric oxide and titania in diopside were also made.

Pure calcium carbonate, magnesia, silica (crushed and washed rockcrystal), alumina, ferric oxide, and titania were used for the preparation of the mixtures. The constituents in their requisite proportions were fused together four or five times with intervening crushing of the quenched glass. The product was an homogeneous glass free from crystalline material.

The question of the system to which perovskite should be referred, and the explanation of the discrepancy between its form and optical-properties, have been the subject of much discussion among crystallograpbers ever since the discovery by Des Cloizeaux, in 1858, of the double refraction of crystals of calciam titanate from Zermatt, having the same composition as the crystals of cubic form from the Ural Mountains, to which the name perovskite had been given by G. Rose in 1889.

When amosite (fibrous grunerite, Fe5·5Mg1·5Si8O22(OH)2), is heated in argon or nitrogen, physically combined water is lost up to 500–700° C. Above 500° C (static) or 700° C (dynamic), dehydroxylation occurs endothermically, giving a pyroxene as the main product. Under dynamic heating conditions, part of the hydroxyl water is lost as hydrogen, with concurrent oxidation of the iron. At about 1000° C the pyroxene is decomposed to olivine and cristobalite; at about 1100° C melting begins. In oxygen or air, physically combined water is again lost below 500–700° C. At 350–1200° C a sequence of overlapping dehydrogenation, oxygen absorption, and dehydroxylation reactions occurs, which gives rise to a broad exotherm on the d.t.a. curve. The main products (for static heating conditions) are an oxyamphibole at 350–800° C, and a spinel, hematite, a pyroxene, and X-ray amorphous material at 800–1100° C. Silica crystallizes as cristobalite at 1100–1350° C, and as tridymite at 1450° C. Most of the products in either neutral or oxidizing atmospheres are formed topotactically. The mechanisms and rates of the reactions are discussed, and the problem of determining the chemically combined water in amosite and other minerals of similar composition is considered.

The occurrence of the minerals is reviewed. Consideration of their genesis leads to a tentative list of primary minerals, and of early diagenetie, later diagenetic and geothermal metamorphic, and late near-surface changes.

Phase relations in the S-poor portions of the dry condensed Pt-Ir-Fe-S system were determined at 1000° and 1100°C with a particular emphasis on delineation of the solid solubility fields of the Pt-Ir-Fe alloys. At both temperatures, a broad field of γ(Ir,Fe,Pt) alloy coexists with γ-(Pt,Fe), Pt3Fe and PtFe which dissolve respectively at least 5.1, 29.3 and 24.0 at.% Ir at 1100°C (2.2, 23.6 and ≤17.2 at.% Ir at 1000°C). Gaps between the nearly Ir-free Pt-Fe alloys γ(Pt,Fe), Pt3Fe s.s., PtFe s.s. and γ(Fe,Pt) were estimated as 20–23 at.%, 40–42 at.% and 54.2–~57 at.% Fe at 1100°C (18–23, 39.5–42.5 and 59–62 at.% Fe at 1000°C). The first gap agrees with data from natural phases by Cabri et al. (1996). The Fe-rich sulphide melt dissolves only traces of Pt and Ir; Fe1–xS dissolves up to 5.8 at.% Ir at 1100°C and 3.4 at.% Ir at 1000°C. These solubilities and the compositions of coexisting alloys (before low-temperature exsolution) may serve as geothermometers. The S-rich melt dissolves up to 8.2 at.% Pt and 2.5 at.% Ir (measured on a solidified melt) at 1100°C. The Fe-Ir thiospinel dissolves up to 2.2 at.% Pt (for the composition Fe21.6Ir18.9Pt2.2S57.3 at 1100°C). The 25–28 at.% Fe portions of Pt3Fe with <10 at.% Ir partake in all important sulphide (± melt)-alloy assemblages (with PtS, Ir2S3, pyrrhotite, S-rich melt and thiospinel). Therefore, their use in recognizing distinct natural assemblages of genetic importance is of limited value.

Cell dimensions obtained from X-ray powder photographs of twenty-four natural olivines and one synthetic forsterite have been related to the cation contents by a new statistical procedure developed by M. H. Hey. Unlike conventional statistical analysis, which assumes error only in one parameter, this procedure simultaneously considers the estimated errors in all variables.

Linear terms in Ca, Mn, Mg (or Fe(≡ 1-Mg-Ca-Mn)) satisfactorily account for the cell dimensions, and there was no need to invoke a term in Mg2. Since there are three cell dimensions and three chemical unknowns, it is theoretically possible to estimate the major cations in olivine just from the cell dimensions. However, the coefficients for Mn and Fe are so similar and the ranges of Ca and Mn are so small that the technique would be impractical.

Data for ideal (Mg,Fe) olivines were estimated by adjusting the cell dimensions by linear extrapolation from the cell dimensions of tephroite and monticellite. A simple chemical term was sufficient to account for each cell dimension. The linear relation between cell volume and Mg is consistent with the complete disorder of Mg and Fe revealed by parallel single-crystal X-ray studies.

The cell dimensions of a synthetic fayalite deviate significantly from those of natural fayalites after correction for the effects of Ca and Mn substitution in the latter: some structural or chemical difference, probably involving ferric iron, is indicated.

No superstructure lines have been found, in contradiction to Eliséev's data.

Flint from the chalk of north-western Europe has long been an ingredient of ceramic 'bodies'. It is still widely used by British pottery manufacturers in glazed tries and in certain types of tableware. Continental manufacturers also have made some use of it.

Flint is more readily converted to cristobalite than are the coarsergrained varieties of quartzose silica. The presence of an adequate amount of cristobalite in the 'body' ensures that, at room-temperature, the glaze-film on the ware shall be under a compressive stress. Thus the development of 'crazing', i.e. of minute tension-fissures in the glaze, tends to be avoided.

The significance of the potential impacts of microbial activity on the transport properties of host rocks for geological repositories is an area of active research. Most recent work has focused on granitic environments. This paper describes pilot studies investigating changes in transport properties that are produced by microbial activity in sedimentary rock environments in northern Japan. For the first time, these short experiments (39 days maximum) have shown that the denitrifying bacteria, Pseudomonas denitrificans, can survive and thrive when injected into flow-through column experiments containing fractured diatomaceous mudstone and synthetic groundwater under pressurized conditions. Although there were few significant changes in the fluid chemistry, changes in the permeability of the biotic column, which can be explained by the observed biofilm formation, were quantitatively monitored. These same methodologies could also be adapted to obtain information from cores originating from a variety of geological environments including oil reservoirs, aquifers and toxic waste disposal sites to provide an understanding of the impact of microbial activity on the transport of a range of solutes, such as groundwater contaminants and gases (e.g. injected carbon dioxide).

Gully pot sediments and pavement and road gutter dusts have been collected from the city of Coventry in the West Midlands, UK. These samples have been subjected to metallic element analysis and the activity of a number of gamma-emitting radionuclides have been measured in order to assess whether they exceed published trigger or action levels, and whether their disposal or dispersal may have implications for receiving landfills and/or water courses. Results indicate above-background levels of metallic elements in dusts and sediments with Cu and Zn exceeding ICRCL action levels in some cases. The highest activities of some radionuclides are found in road gutter and street dusts and the lowest activities are found in gully pot sediments. Road dusts are more likely to be recirculated into the ambient air by passing traffic and could potentially pose a risk to pedestrians. The effective dose rates calculated for these dusts and sediments indicate that some samples approach and even exceed the 1 mSv y—1 limit to members of the public recommended by ICRP (1991). Some individual nuclides exceed their clearance levels laid down in the revised basic safety standards of the 1993b Radioactive Substances Act, 1993 (DoETR, 1999), by as much as 2.5 times. This is especially true of 210Pbun and 7Be, two fallout nuclides, and also of 40K.