Homogeneous glasses for the use as standards in electron-probe microanalysis were prepared as an alternative to natural minerals, oxides, and pure minerals. Homogeneity was achieved by careful grinding, mixing, and fusion of powders of known composition. Fusion was carried out under vacuum using a molybdenum boat. This method avoided bubbles and contamination and made it possible to achieve temperatures high enough for final mixing to occur during the fusion process. Nine glass beads each containing six to seven oxides were subjected to careful micro-probe examination. A statistical analysis of the results showed that for each element there was no significant difference in composition between the spots measured. As the analysing spot was of diameter 0·8 µ, this showed that the glasses were homogenous on a sub-micron scale.

A CO-bearing member of the hydroxylapatite–hydroxylellestadite series occurs as a Si-rich part of a hydroxylapatite–hydroxylellestadite series mineral (hydroxylapatitess) in a skarn xenolith from Tadano, Fukushima Prefecture, Japan. Hydroxylapatitess is composed of Si-poor and Si-rich parts. The Si-poor part is F-rich hydroxylapatite. The infrared spectrum of the Si-rich part demonstrates the presence of B-type CO3. A representative analysis of the Si-rich part yielded the empirical formula Ca4.989[(PO4)1.315 (SiO4)0.848 (SO4)0.368(CO2.943)0.480]∑3.011(OH0.629 Cl0.264 F0.107)∑1.000 on the basis of 8 cations, assuming Si = S + C. There is a very strong inverse correlation between Si and P in both the Si-poor and Si-rich parts. These data indicate that the substitution mechanism (SO4,CO3)2– + (SiO4)4– = 2(PO4)3– probably occurs in hydroxylapatite ss. Therefore, it was concluded that the Si-rich part corresponds to a CO3-bearing hydroxylapatite–hydroxylellestadite series mineral with CO3 partially replacing SO4. Most of the Si-rich part shows CO3 > SO4 and its composition approaches Ca5(SiO4)1.5(CO3,SO4)1.5(OH,Cl,F).

Acid mine drainage (AMD) commonly contains elevated concentrations of As(III) and/or As(V) due to oxidation of arsenic-containing sulfides. Bone char has been used as a low-cost filling material for passive treatment. The breakthrough curves of As(III) and As(V) were studied in column experiments conducted at different flow rates, adsorption cycle times, and with different coexisting cations and anions to compare their transport behaviours. The experimental data were fitted by the Convection- Diffusion Equation (CDE) and Thomas model with the aim of obtaining retardation factors of As(III) and As(V) and their maximum adsorption capacities, respectively. The maximum adsorption capacities of As(III) and As(V) are 0.214 and 0.335 mg/g, respectively. Coexisting Mn2+ and Al3+ ions can shorten the equilibrium time of As(V) adsorption from 25 h to 8 h, but they have little effect on As(III). The retardation factors of As(III) and As(V) calculated by the CDE model decrease with adsorption cycles from 37 to 20 and 51 to 32, respectively. The Mn2+ and Al3+ ions could enhance retention ability with adsorption cycle time, especially Mn2+ for As(V). Secondary adsorption phenomena were observed only in breakthrough curves of As(V) in the presence of Mn2+ and Al3+. The competitive influences of coexisting arsenic species is As(V) > As(III). Regeneration experiments using distilled water and NaOH solution were completed to quantify the degree of desorption of both As(III) and As(V). The results show that As(V) adsorbed on bone char has better desorption performance than As(III), and the average degrees of desorption of As(III) and As(V) for three desorption experiments are 75% and 31%, respectively.

Both new species are retrograde or mesogene minerals that occur in tactites at the Christmas mine, Gila County, Arizona (USA). Gilalite is green, H = 2, D = 2.82. Biaxial (—), 2V small, α = 1.560, β = γ = 1.635. No single crystals found; strongest lines at 13.49 Å, (10); 10.97 (5); 7.786 (5). Analysis gave CuO 36.2%, MgO 2.3, CaO 3.8, MnO 0.5, SiO2 41.5, H2O 14.6, close to Cu5Si6O17·7H2O.

Apachite is blue, H = 2, D = 2.80. Biaxial (—), 2V small, α = 1.610, β = γ = 1.650. No single crystals found. Strongest lines are 12.90 Å (10); 3.168 (7); 7.663 (5). Analysis gave CuO 43.6%, FeO 0.3, MgO 1.7, CaO 1.8, SiO2 40.8, H2O 13.8, close to Cu9Si10O29·11H2O.

Camptonite sills of Permian age, intruded into Cambrosilurian sediments, are present in the northern part of the Oslo region, immediately to the north of Gran, Hadeland. They have been considered, along with associated dykes of camptonite and other minor intrusions of maenaite, to be related to the predominantly gabbroic rocks comprising the Oslo-essexite plugs (Brögger, 1894). Porphyritic varieties of camptonite are the most common, containing phenocrysts of concentrically zoned clinopyroxene and concentrically zoned brown amphibole; but, aphyric varieties with abundant brown amphibole also occur. A second amphibole (actinolite) forms thin, patchy, green overgrowths to some phenocryst or matrix brown amphiboles.

The pyroxenes range in composition from diopside to sahlite. They contain up to 0.7% Cr2O3 in the most Mg-rich zones and up to 0.6% Na2O in the most Fe-rich zones. TiO2 and Al2O3 are in the ranges 0.5–3.8% and 3.0–9.2% respectively. These compositions are similar to pyroxenes from other camptonites and alkali basaltic and alkali gabbroic rocks. ‘Normal’ zoned phenocrysts, in which an outer pinkish zone surrounds a colourless core in thin section, have more Fe, Ti, and Al, and less Mg and Si in the outer zone. In ‘reversed’ zoned crystals, the slightly pinkish core contains more Fe, Ti, and Al, and less Mg and Si. Oscillatory zoning, restricted to three concentric zones (pinkish-colourless-pinkish) show the same chemical changes with colour variation. In terms of end-member molecules, substitutions involving CaTiAl2O6, CaAl2SiO6 plus CaFeSi2O6 replacing CaMgSi2O6 are responsible for the zoning.

The majority of the zoned brown amphiboles are kaersutite following the criteria of Leake (1978). Those zones with Ti < 0.5 atoms per formula unit range from titanian pargasite and titanian ferroan pargasite to titanian ferro-pargasite. These compositions are similar to kaersutites crystallizing from other camptonites and as inclusions, or as megacrysts and phenocrysts in alkali basalts and derivative rocks. A simple concentric zoning with more Fe and less Mg in the outer zones occurs; but, an oscillatory zoning pattern, with an intermediate lighter brown zone (containing more Mg and less Fe) between two concentric darker zones, is more common. Other elements do not show consistent variations between zones, but Ti generally increases with increase in Aliv.

It is postulated that the earliest pyroxene zones crystallized from an alkali basalt magma at approximately 20 km depth. Crystallization of the remainder of the pyroxene phenocrysts and the kaersutite took place at high temperatures (> 940 °C) and at probably greater depths (7–15 km) than crystallization of nearby exposed gabbroic plugs (Oslo essexites). A mechanism of alternate crystallization of pyroxene and kaersutite in response to changes in PH2O, with some partial resorption of the non-crystallizing phase, is suggested to account for the observed petrographic features and oscillatory zoning in both minerals. The actinolite is a product of late-stage metasomatic activity.

MacFallite, Ca2(Mn3+,Al)3(OH)3[SiO4] [Si2O7], is a new species occurring with manganite, braunite, orientite and pyrolusite blebs, stringers, and framboidal aggregates, which replace calcite in fissures and lenses in Keweenaw basalt near Manganese Lake, Copper Harbor, Keweenaw County, Michigan. It is rich reddish brown to maroon in coarse aggregates; compact massive material is brown to dull pink. The streak and powder are brown with a reddish tint. Lustre silky to subadamantine, specific gravity 3.43(2), hardness 5+, cleavage {001} perfect; twinning by reflection on {100} is universal. The mineral is monoclinic, space group P21, or P21/m, Z = 2, a 8.929(6), b 6.045(5), c 10.905(7) Å, β 119.10(3)°, α 1.773(5), β 1.795(5), γ 1.815(5), sign + or −, pleochroism α yellow, β light brown, γ dark brown, γ‖b. Orientite, Ca2Mn 2+ (OH)4[Si3O10]-Ca2 (OH)2[Si3O10] ·2H2O, orthorhombic, space group Cc2m, Ccm21or Ccmm, a 9.042(4), b 6.090(2), c 18.990(7) Å, α 1.765(5), β 1.79(1), γ 1.81(1), sign + or −, α brownish yellow, β reddish brown, γ deep brownish red, α‖a, γ‖b, also occurs in moderate abundance. It is turbid chocolate brown in platy masses but crystals are transparent rich reddish brown. Streak and powder brown. Observed forms are m{110}, c{001}, and poorly developed to absent α{100}, thin to thick tabular parallel to {001}, cleavage (or parting) {001} perfect, specific gravity 3.33.

A fumarolic origin is proposed for the assemblage, which in many respects is similar to the great manganese oxide deposits in Oriente Province, Cuba. Macfallite appears to be structurally related to pumpellyite while orientite is apparently related to ardennite.

The sorption behaviour of I−, Cs+, Ni2+, Eu3+, Th4+ and UO2+ 2on NRVB (Nirex reference vault backfill) a possible vault backfill, at pH 12.8 was studied. Sorption isotherms generated were compared to results obtained in the presence of cellulose degradation products (CDP). Whereas Cs was not affected by the presence of the organic compounds, a notable reduction in the sorption of Th and Eu to cement was observed. The results also indicated limited removal of Ni from solution (with or without an organic ligand) by sorption, the concentration in solution seemingly being determined solely by solubility processes. In the case of uranium, the presence of CDP increased the sorption to cement by almost one order of magnitude. Further studies into the uptake of CDP by cement are being undertaken to identify the mechanism(s) responsible.

The nature and mode of origin of quartz-cored tourmalines (QCT) are studied from hydrothermal quartz veins within massive quartz-tourmaline (MQT) rocks at Roche, SW England. The QCT are annular, have blue maximum absorption colour and occur together with tourmalines with brown cores rimmed by blue tourmaline. Where the quartz core is not continuous throughout the length of the QCT crystals, the tourmaline core has brown maximum absorption colour, similar to tourmalines without quartz cores. Both the blue and brown tourmalines are schorl, but are compositionally distinct showing different Fe/(Mg + Ti) ratios and Ca concentrations. Fluid inclusion data indicate quartz precipitation from a moderate salinity (∼20–25 wt.% NaCl eq.) brine which periodically boiled following pressure drops within the vein system. The QCT show rheomorphic and lobate textures on their inner margins indicating selective dissolution of their brown, relative Mg-, Ti- and Ca-rich tourmaline cores and replacement with quartz. This presents a problem in terms of the nature of the fluid responsible for such selective dissolution because tourmaline is generally highly resistant under the normal range of hydrothermal fluid conditions. It is proposed that the relatively high concentrations of Ti, Mg and Ca in the brown tourmaline caused significant lattice strain, which together with an increase in pH, and probably Al, in the boiling hydrothermal fluid caused the brown cores to become unstable compared with the Fe-rich blue tourmaline rims.

Scheelite mineralization in the granulite-facies supracrustal sequences of the Kerala Khondalite Belt, southern India is reported. The supracrustal sequences where the mineralization is found comprise granulite-grade metasediments which underwent metamorphism at ∼550 Ma. The mineralization is assumed to have formed by late-stage metasomatism that overprinted the regional metamorphism of the country rock (garnet-biotite gneiss) and occurs along a quartz vein that intrudes the regional foliation. The paragenetic data from the vein demonstrate unambiguously a separate cycle of hydrothermal activity, resulting in metasomatism and mineralization. Scheelite is found in both the altered host rock along the foliation plane and in the quartz vein. Fluid inclusions preserved in the vein suggest that the mineralizing fluids were saline-aqueous in composition, while those in the country rocks were predominantly CO2-rich. The mineral chemistry and bulk-rock chemical composition of the mineralized domain reveal the unusual enrichment of Ca in the mineralised zone with the depletion of K. We propose that fluid discharging from a crystallizing deep-seated magma, mixing with deep circulating Ca-bearing palaeo-groundwater gave rise to the deposition of scheelite. The scheelite mineralization and the quartz vein emplacement occurred after the Pan-African regional metamorphism.

Metavivianite has been shown to be not dimorphous with vivianite. Assuming the homogeneity and uniformity of the original type samples, it is a triclinic hydrated ferri-ferrous hydroxy phosphate whose formula may be given as Fe2+3-xFe3+x(po4)2(OH)x(8-x)H2O where x > 1.4. The precise oxidation limits between which the triclinic lattice is stable are not known but the structure persists close to total oxidation of all iron. The structure of metavivianite was established using a fragment of kerchenite whose formula as originally given is covered by the general metavivianite formula. Assuming the homogeneity of the original (1907) samples, kerchenite and metavivianite appear to be identical.

Waimirite-(Y) (IMA 2013-108), orthorhombic YF3, occurs associated with halloysite, in hydrothermal veins (up to 30 mm thick) cross-cutting the albite-enriched facies of the A-type Madeira granite (∼1820 Ma), at the Pitinga mine, Presidente Figueiredo Co., Amazonas State, Brazil. Minerals in the granite are 'K-feldspar', albite, quartz, riebeckite, 'biotite', muscovite, cryolite, zircon, polylithionite, cassiterite, pyrochlore-group minerals, 'columbite', thorite, native lead, hematite, galena, fluorite, xenotime-(Y), gagarinite-(Y), fluocerite-(Ce), genthelvite–helvite, topaz, 'illite', kaolinite and 'chlorite'. The mineral occurs as massive aggregates of platy crystals up to ∼1 μm in size. Forms are not determined, but synthetic YF3 displays pinacoids, prisms and bipyramids. Colour: pale pink. Streak: white. Lustre: non-metallic. Transparent to translucent. Density (calc.) = 5.586 g/cm3 using the empirical formula. Waimirite-(Y) is biaxial, mean n = 1.54–1.56. The chemical composition is (average of 24 wavelength dispersive spectroscopy mode electron microprobe analyses, O calculated for charge balance): F 29.27, Ca 0.83, Y 37.25, La 0.19, Ce 0.30, Pr 0.15, Nd 0.65, Sm 0.74, Gd 1.86, Tb 0.78, Dy 8.06, Ho 1.85, Er 6.38, Tm 1.00, Yb 5.52, Lu 0.65, O (2.05), total (97.53) wt.%. The empirical formula (based on 1 cation) is (Y0.69Dy0.08Er0.06Yb0.05Ca0.03Gd0.02Ho0.02Nd0.01Sm0.01Tb0.01Tm0.01Lu0.01)Σ1.00[F2.54〈0.25O0.21]Σ3.00. Orthorhombic, Pnma, a = 6.386(1), b = 6.877(1), c = 4.401(1) Å, V = 193.28(7) Å3, Z = 4 (powder data). Powder X-ray diffraction (XRD) data [d in Å (I) (hkl)]: 3.707 (26) (011), 3.623 (78) (101), 3.438 (99) (020), 3.205 (100) (111), 2.894 (59) (210), 1.937 (33) (131), 1.916 (24) (301), 1.862 (27) (230). The name is for the Waimiri-Atroari Indian people of Roraima and Amazonas. A second occurrence of waimirite-(Y) is described from the hydrothermally altered quartz-rich microgranite at Jabal Tawlah, Saudi Arabia. Electron microprobe analyses gave the empirical formula (Y0.79Dy0.08Er0.05Gd0.03Ho0.02Tb0.01Tm0.01Yb0.01)Σ1.00[F2.85O0.08〈0.07]Σ3.00. The crystal structure was determined with a single crystal from Saudi Arabia. Unit-cell parameters refined from single-crystal XRD data are a = 6.38270(12), b = 6.86727(12), c = 4.39168(8) Å, V = 192.495(6) Å3, Z = 4. The refinement converged to R1 = 0.0173 and wR2 = 0.0388 for 193 independent reflections. Waimirite-(Y) is isomorphous with synthetic SmF3, HoF3 and YbF3. The Y atom forms a 9-coordinated YF9 tricapped trigonal prism in the crystal structure. The substitution of Y for Dy, as well as for other lanthanoids, causes no notable deviations in the crystallographic values, such as unit-cell parameters and interatomic distances, from those of pure YF3.

We have applied atomistic simulation techniques to model the continuous CdCO3-CaCO3 solid solution and to investigate the thermodynamic properties. All inequivalent substitutional configurations were considered for the single unit cell and the (2x1x1) supercell for the full range of Cd concentrations, as well as doping between 0and 16.7 mol.% Cd for the (2x2x1) supercell. Our calculations show that segregation of Cd2+ and Ca2+ is energetically favourable when compared with any other cation distribution. No cation ordering is expected at high temperature and the system behaves as an ideal solid solution above 200 K, due to the configurational entropy. The lattice parameters change with the Cd concentration, where they are predicted to follow a linear relationship, due only to cation substitution but not cation ordering.

The Kærven syenite complex, which reflects the hitherto earliest recorded stages in the Tertiary of East Greenland, outcrops in the middle reaches of the Kangerdlugssuaq Fjord as a peripheral intrusion to the Kangerdlugssuaq intrusion. The rocks of the Kærven complex range from syenite through alkali feldspar quartz-syenite to alkali feldspar granite. The general sequence of crystallization of the Kærven magmas was: alkali feldspar ± olivine(Fa96−99) ± plagioclase(An41−11), clinopyroxene (augite, ferrosalite, ferrohedenbergite), quartz and amphibole. Whole-rock major and trace-element data show coherent geochemical trends which suggest comagmatism. The data reveal that the Kærven rocks are distinct from the rocks from the adjacent Kangerdlugssuaq intrusion (e.g. higher TiO2, FeOT in low-SiO2 samples, lower Na2O, approx. constant Zr/Nb). The mineral chemistry supports this conclusion, as the Kærven samples typically have calcic amphiboles and clinopyroxenes with a very limited Na-enrichment in contrast to the sodic trends of the Kangerdlugssuaq intrusion. Normative feldspar compositions plot near to the Ab-Or cotectic in the Q-Ab-Or system and a maximum pressure of crystallization of 3–5 kbar with moderate to low PH2O is indicated.

Trace elements preferently incorporated in plagioclase and alkali feldspar, i.e. Sr, Ba and Rb, show systematics which are not compatible with an evolution of the rock suite by crystal fractionation of these phases, though possibly alkali feldspar may be partially accumulated in a few very evolved rocks. Numerical calculations do not suggest a magmatic evolution by fractional crystallization of the observed phases. The variation of Sr, Ba and Rb as well as of the incompatible elements Nb, Zr and Th support a derivation of the rock suite mainly by mixing two components, a syenitic and a granitic end-member. It is concluded that magma mixing was the most significant process in the formation of the Kærven rock suite accompanied by some crystal fractionation. Evidence for crustal contamination is detected in a few samples from the outer part of the intrusion but has not affected the main suite of rocks.

Idioblastic, mm-scale brookite is reported from SiO2-Ba-Fe-rich metasomatic rocks from the carbonatitic Gross Brukkaros Volcanic Field, Southern Namibia. Electron probe microanalysis shows significant concentrations of Nb (12–17 wt.% Nb2O5), coupled with Fe, substituting for Ti in the structure. Calculation of the analytical data indicates evolving Fe2+/(Fe2++Fe3+) ratios during crystallization and two distinct substitution mechanisms in operation: 2Ti4+ ⇋ Nb5+ + Fe3+ and 3Ti4+ ⇋ 2Nb5+ + Fe2+. The compositional patterns observed are explained in terms of initial growth in an environment which evolved from oxidizing to reducing. The outermost 10 µm rims of the crystals are characterized by oxidizing conditions, resulting from a subsequent metasomatic overprint.

Holtite, (Si2.25Sb0.75)B[Al6(Al0.43Ta0.27□0.30)O15(O,OH)2.25], is orthorhombic a = 4.6914(5), b = 11.896(2), c = 20.383(4)Å, space group Pnma. Full-matrix least-squares refinement yielded a final R = 0.030, for 1664 reflections with I ⩾ 3σ(I). Its crystal structure is closely related to that of dumortierite, but with the difference that extensive substitution of Si by Sb occurs in holtite. SbO3 triangular pyramids replace the SiO4 tetrahedra arranged around the inside edge of the hexagonally shaped tunnels which are the feature of the dumortierite and holtite structures. Associated with these replacements is the replacement of Al by Ta in the octahedral site centred in these tunnels, and the development of vacancies in this metal site and its attached oxygens.

Bobshannonite, Na2KBa(Mn,Na)8(Nb,Ti)4(Si2O7)4O4(OH)4(O,F)2, is a new TS-block mineral from Mont Saint-Hilaire, Québec, Canada. It occurs as blocky crystals 0.5–1 mm across,perched on sérandite and albite. Other associated minerals are epididymite, catapleiite, aegirine, kupletskite, rhodochrosite and rhabdophane-(Ce). Bobshannonite occurs as vitreous to frosty, transparent to translucent very pale brown to orange brown crystals, has a very pale brown streak, hackly fracture and does not fluoresce under cathode or ultraviolet light. Cleavage is {001} very good, no parting was observed, Mohs hardness is ∼4, it is brittle and Dcalc. = 3.787 g/cm3. Crystals are twinned extensively and do not extinguish in cross-polarized light. Bobshannonite is triclinic, C1, a = 10.839(6), b = 13.912(8), c = 20.98(1) Å, α = 89.99(1), β = 95.05(2), γ = 89.998(9)°, V = 3152(5) Å3. The six strongest reflections in the powder X-ray diffraction data [d (Å),I, (hkl)] are: 2.873, 100, (241, 241, 044, 044, 241, 241); 3.477, 60, (006); 3.193, 59, (224, 224); 2.648, 40, (402, 243, 243); 2.608, 35, (008, 226, 226); 1.776, 30, (249). Chemical analysis by electron microprobe gave Ta2O5 0.52, Nb2O5 19.69,TiO2 5.50, SiO2 26.31, Al2O3 0.06, BaO 7.92, ZnO 1.02, FeO 0.89, MnO 26.34, MgO 0.06, Rb2O 0.42, K2O 2.38, Na2O 4.05, F 0.70, H2Ocalc. 1.96, O = –0.29, total 97.53 wt.%, where the H2O content was calculated from the crystal-structure analysis. The empirical formula on the basis of 38 anions is Na1.89(K0.93Rb0.08)Σ1.01Ba0.95(Mn6.85Na0.52Zn0.23Fe0.232+Mg0.03Al0.02)Σ7.88(Nb2.73Ti1.27Ta0.04)Σ4.04(Si8.07O28)O9.32H4.01F0.68,Z = 4. The crystal structure was refined to R1 = 2.55% on the basis of 7277 unique reflections [F > 4σ(F)] and can be described as a combination of a TS (Titanium Silicate) block and an I (Intermediate) block. The TS block consists ofHOH sheets (H – heteropolyhedral, O – octahedral). The topology of the TS block is as in Group II of the Ti disilicates: Ti + Nb = 2 a.p.f.u. per (Si2O7)2 [as defined by Sokolova (2006)]. In the O sheet, ten[6]MO sitesare occupied mainly by Mn, less Na and minor Zn, Fe2+, Mg and Al, with <MO–ϕ> = 2.223 Å. In the H sheet, four [6]MH sites are occupied by Nb and Ti (Nb > Ti), with <MH–ϕ> = 1.975 Å,and eight [4]Si sites are occupied by Si, with <Si–O> = 1.625 Å. The MH octahedra and Si2O7 groups constitute the H sheet. The TS blocks link via common vertices of MH octahedra. In the I block, Ba and Kare ordered at the AP(1) and AP(2) sites with Ba:K = 1:1 and the two BP sites are occupied by Na. The ideal composition of the I block is Na2KBa a.p.f.u. Bobshannonite, perraultite, surkhobite and jinshajiangite are topologically identical Group-II TS-block minerals. Bobshannonite is the Nb-analogue of perraultite. The mineral is named bobshannonite after Dr. Robert (Bob) D. Shannon (b. 1935), in recognition of his major contributions to the field of crystal chemistry in particular and mineralogy in general through his development of accurate and comprehensive ionic radii and his work on dielectric properties of minerals.

Vein formation occurred throughout a deformation sequence which involved early transpressive ductile deformation through to late-kinematic transpressive brittle structures which host a series of gold prospects. Fluid inclusion data from (S1) fabric parallel veins associated with early deformation suggest that a low-salinity aqueous fluid, with a mean salinity of 6.4 wt.%, was present during peak metamorphism, Pelite mineralogy and isochores constrain peak metamorphism to the lowermost part of the upper greenschist facies at 325 to 425°C and 1.4 to 3.4 kbar.

Fluid inclusion data from auriferous and barren late-kinematic quartz veins, both containing unmixing assemblages of aqueo-carbonic inclusions with low salinities of ≈2.7 wt.% NaCl equiv., indicate unmixing occurred at 300°C and 1.5 kbar.

Volatiles (CO2, N2, CH4) are observed in all the late-kinematic veins. The N2 contents of veins with elevated gold grades are typically higher than those with low gold grades. N2 reaches 8.7 mole% in a vein with 0.49−4.6 p.p.m. Au compared to <1 mole% in a vein with <0.05 p.p.m. Au. The CH4 content of late kinematic veins is generally less than 1 mole% and shows no relative enrichment in mineralised veins. The generation of N2 in the mineralising fluid most likely results from interaction of fluid with the ammonium ion, NH4+, in micas and feldspars. This interaction could take place either at source, due to metamorphic devolatisation reactions, or along those structures which acted as fluid conduits due to fluid-rock interaction.

Rock deformation and metamorphism can interact at the mechanistic level in the following ways: (a) facilitation of cataclasis through the release of high-pressure fluid during dehydration and decarbonation reactions; (b) facilitation of intracrystalline plasticity through the stresses induced during solid-state volume changes; (c) enhanced deformability through the transient existence of fine-grained reaction products; (d) modification of chemical potential gradients driving diffusion if a reaction can occur along the diffusion path; (f) changes in the resistance to intracrystalline plasticity through the effect of reaction-induced changes, pore fluid pressure and chemistry on point defect chemistry of the solid phases.

Examples of experimental studies of each of these types of interaction are described. Special experimental problems arise through: (i) the effects of solid phase and pore space volume changes, and their effects on pore fluid pressure and measured strain; (ii) the effects of such microstructural changes on the determination of flow law parameters; and (iii) in many instances the need for very long duration deformation experiments if reaction kinetics are sluggish.

There is an outstanding need for experimental studies of the effects of non-hydrostatic stress on the conditions for the onset of metamorphic reactions and phase transformations, as a basis for understanding some classes of deformation/metamorphism interaction. However, it is emphasized that the threefold classification of rock deformation mechanisms into cataclastic, crystal-plastic, and diffusive mass transfer processes, established from the study of deformation of monomineralic rocks, forms an essential framework for the understanding of deformation/metamorphism inter-relationships.

Clinopyroxene phenocrysts and groundmass crystals are relict phases in altered basalt and basaltic andesite lavas, and arenites of the Cudgegong Volcanics and Toolamanang Volcanics, Cudgegong-Mudgee district, New South Wales. Petrography, field relationships and clinopyroxene compositions indicate that basaltic blocks in the latter unit are reworked from the Cudgegong Volcanics. Clinopyroxene phenocrysts show a restricted compositional range and minor Feenrichment from core to rim, features considered indicative of a calc-alkaline parent magma. It is proposed that the Cudgegong Volcanics crystallized under hydrous conditions, at least in the later stages, with rising fO2 resulting in a Fe-Ti oxide crystallizing as a primary phase. The clinopyroxenes are considered to have crystallized at moderate (5–6 kbar) and falling pressures and at minimum temperatures in the range 900 to 1000°C. Coupled substitutions affecting the “other” components in the clinopyroxene structural formula indicate that the ivAl-viFe3+, ivAl-viAl and ivAl-viTi4+ couples are important. The Sofala Volcanics, south of the study area, and the Cudgegong Volcanics are similar in age, petrography and stratigraphic position, and contain relict clinopyroxenes which are chemically similar. This suggests that the units are laterally equivalent and adds further evidence to the proposal that an oceanic island arc system was active in central western New South Wales during the Late Ordovician.

Sixteen fluorapatite specimens from regional skarns in granulite terrain were associated with Al-zoned diopside ± scapolite ± actinolite ± calcite(+ rare phlogopite). Apatite was low in Ce (ave. 0.19% Ce2O3) and enriched in LREE relative to HREE (La/Yb = 31 to 74 in 4 specimens). Some specimens showed small negative Eu anomalies and some crystals were zoned in REE. SrO averaged 0.36%. The mineral contained some carbonate (ave. 0.5% CO2 in 5 specimens), appreciable silica (ave. 0.5%), and variable sulphate (0.1 to 1.2% SO3). Excess charge due to S6+ was largely compensated by Si4+. Chlorine was minor and F accounted for 75–98% of the F, Cl and OH ions. Apatite from marble lacking amphiboles and pyroxenes has a similar chemical composition, but apatite from later carbonatite and fenite contains more Ce and Sr. Apatite from Gatineau fenite, Gatineau carbonatite and world-wide siliceous igneous rock generally contains less S. Apatite from Gatineau skarns normally contains more Cl and less S than that from phosphorite. Magnesian marble was silicated to skarn by reaction with siliceous gneiss. Phosphorus, REE, and Sr were removed from nearby rocks and transported in aqueous, carbonated solutions containing minor amounts of F, Cl and S at granulite-facies conditions. Apatite and calcite precipitation took place in skarns and marble during the Grenville (Proterozoic) orogeny.