The Inagli complex, one of several Mesozoic intrusive complexes of the Aldan Shield (Siberian Platform), exhibits a concentric structure comprising several alkaline ultramafic rock-types. A central dunite body is surrounded by olivine- and phlogopite-clinopyroxenites forming an inner rim. The outer rim consists of different shonkinitic and malignitic rocks. The K-Ar ages obtained for the whole complex vary around 132 Ma.

The dunites and clinopyroxenites are characterized by cumulate textures. With increasing modal abundances of clinopyroxene and subordinate phlogopite, the rocks develop to olivine-clinopyroxenite, shonkinite, and malignite with intercumulus potassium feldspar. Mineralogical characterization of the rocks suggests they evolved by fractional crystallization. The highly forsteritic olivines (Fo up to 95) require a melt as magnesian as mg# 87.1, representing ±26 wt.% MgO. The parental melt is likely to be an olivine-, H2O- and K2O-rich picritic liquid of shoshonitic character. Major and trace element systematics show high LILE/LREE and LREE/HFSE ratios indicating the involvement of a subduction zone component in the genesis of these rocks.

Textures produced by reactions involving garnet in a sillimanite-staurolite schist have been investigated using an irreversible thermodynamic model. The model predicts that the local production or consumption of garnet is strongly influenced by the proximity of garnet to growing sillimanite and dissolving staurolite. Garnets within sillimanite segregations should dissolve near the sillimanite-bearing centre of the segregation while garnets within or adjacent to staurolite poikilo-blasts should grow as the staurolite is replaced by a muscovite-rich pseudomorph. Garnets located in the matrix may grow, not react at all, or dissolve depending on the local configuration of nearby sillimanite, staurolite, and garnet. Textures predicted by the model are similar to those observed in thin section: many garnets are truncated within sillimanite segregations; garnets located in pseudo-morphs after staurolite are equant and have thick unpoikilitic rims that suggest growth; most matrix garnets also have thick inclusion-free rims that suggest growth but a few have thin rims, indicating little growth, or are irregularly shaped, suggesting dissolution.

The new mineral mössbauerite (IMA2012−049), Fe6 3+O4(OH)8[CO3]·3H2O, is a member of the fougèrite group of the hydrotalcite supergroup. Thus, it has a layered double hydroxide-type structure, in which brucite-like layers [Fe6 3+O4(OH)8]2+ are intercalated with CO3 2− anions and water molecules. Mössbauerite is the fully oxidized analogue of fougèrite and trébeurdenite, related to them chemically by the exchange of (Fe3+O2−) with (Fe2+OH−). Mössbauerite, intimately intergrown with trébeurdenite, was discovered in intertidal gleys from Mont Saint-Michel Bay, France, along with quartz, feldspars and clay minerals. Mössbauerite is formed by the oxidation of the other members of the fougèrite group. Like them, it occurs as μm-scale platelets in gleys with restricted access to atmospheric O and decomposes rapidly when exposed to air. Identification and characterization of these minerals has relied on an electrochemical study of synthetic analogues and Mössbauer spectroscopy, which inspired the name of the new mineral.

Unlike fougèrite and trébeurdenite, which are blue-green, pure synthetic mössbauerite is orange in colour. Detailed optical and other physical properties could not be determined because of the small platelet size and instability. The hardness is probably 2−3, by analogy with other members of the supergroup and the density, calculated from unit-cell parameters, is 2.950 g/cm3. Synchrotron X-ray data indicate that the natural material is a nanoscale intergrowth of 2T and 3T polytypes; the latter probably has the 3T7 stacking sequence. The corresponding maximum possible space group symmetries are P m1 and P3m1. Unit-cell parameters for the 3T cell are a = 3.032(7) Å, c = 22.258(4) = 367.420 Å and Z = ½.

Mössbauer spectroscopy at 78 K indicates that two distinct Fe3+ environments exist in a 2:1 ratio. These are interpreted to be ordered within each layer, but without the development of a threedimensional superlattice. Mössbauerite undergoes gradual magnetic ordering at 70−80 K to a ferromagnetic state, below which it splits into three sextets S 1m, S 2m and S 3m, as measured at 15 K, and shows the same intensity ratio ½:⅙:⅓ as the three doublets for fougèrite D 1f, D 2f, D 3f in the paramagnetic state at 78 K. This suggests that there is also short-range coupling of interlayer carbonate anions with respect to the octahedral layers and that the 2D long-range order of carbonates in interlayers remains unchanged.

Zadovite, BaCa6[(SiO4)(PO4)](PO4)2F (R3m, a = 7.0966(1) Å, c = 25.7284(3), V = 1122.13(3) Å3, Z = 3) and aradite, BaCa6[(SiO4)(VO4)] (VO4)2F (R3m, a = 7.1300(1), c = 26.2033(9) Å, V = 1153.63(6) Å3, Z = 3) are two new mineral species of a novel modular structure type related closely to the structure of nabimusaite, KCa12(SiO4)4(SO4)2O2F. Both minerals occur in paralavas enclosed in pyrometamorphic rocks of the Hatrurim Complex, Negev desert, Israel. Zadovite and aradite are colourless, transparent with a white streak, have a vitreous lustre and an uneven fracture. Both minerals are uniaxial (–) with refractive indices (589 nm) ω = 1.711(2), ε = 1.708(2) (zadovite) and ω = 1.784(3), ε = 1.780(3) (aradite). The zadovite structure type comprises two tetrahedral sites, which may host a broad compositional range of atoms such as Si, P, V and S. Results of electron microprobe analyses show a correlation between excess Si4+ and S6+ contents, suggesting the substitution scheme 2(P,V)5+ = Si4+ + S6+ at the tetrahedral sites. This points to the possibility of new minerals isostructural with zadovite with end-member formulae BaCa6(SiO4)2[(PO4)(SO4)]F, BaCa6(SiO4)2[(VO4)(SO4)]F, BaCa6[(SiO4)1.5(SO4)0.5](PO4)2F and BaCa6[(SiO4)1.5(SO4)0.5](VO4)2F. The Raman spectra of aradite and zadovite reflect the varying PO4 (e.g. change of band intensity at ∼1031 cm–1) and VO4 contents (e.g. change of band intensity at ∼835 cm–1). The presence of SO4 leads to an additional Raman band at ∼997 cm–1. The structure of zadovite-series minerals belonging to the nabimusaite group is characterized by a 1:1 alternation of antiperovskite-like {[FCa6](TO4)2}4+ modules and Ba(TO4)2–4 modules.

A detrital assemblage of magnesian ilmenite, pyrope, chrome-diopside, rutile, and zircon has been traced to outcropping ultrabasic alkaline rocks, hitherto unknown in the Melanesian region. Analyses and descriptions of these ‘kimberlite indicator minerals’ are given. The host rocks comprise alnöite, an alnöite breccia with calcite matrix, and a magnesian ankaratrite, which are described, with chemical analyses. Emphasis is laid on the abundance of ultrabasic inclusions and xenocrysts and the replacements and transformations they have undergone. Malaita Island promises to contribute significantly to the understanding of the relations between alnöite, melilite basalts, and kimberlites.

A detailed mineralogical examination of representative material from the P2-West 'kimberlite' located in the Wajrakarur Kimberlite Field (India) demonstrates that significant differences exist between these rocks and archetypal hypabyssal kimberlite. The intrusion consists of an olivine-phyric facies which has been transected by, and includes clasts of, a consanguineous phlogopite-rich pegmatitic facies. The olivine-rich parts of P2-West are relatively fresh and consist of euhedral-to-subhedral microphenocrystal olivine set in a groundmass of fine-grained anhedral monticellite, amoeboid apatite, and subhedral-to-euhedral perovskite within a partially chloritized-to-fresh phlogopite-rich mesostasis. The rock lacks the abundant olivine macrocrysts characteristic of kimberlite. Monticellite crystals are commonly partially or completely replaced by pectolite and hydrogarnet. Similar material occurs as irregular aggregates randomly scattered throughout the groundmass. The groundmass, in contrast to that of hypabyssal kimberlites, is relatively poor in spinels. Atoll spinels are absent, with the majority of spinels occurring principally as mantles upon microphenocrystal olivine. Disaggregated cumulate-like assemblages of intergrown anhedral perovskite and spinel are common. Spinel compositions are unlike those of kimberlites and their evolutionary trend is similar to that of lamproite and lamprophyre spinels. The pegmatitic facies of the intrusion are highly and pervasively altered, and characterized by the presence of large clasts, veins, and irregular aggregates consisting of large (1–5 mm) crystals of pinkish-bronze Al-poor phlogopite intergrown with and/or including: apatite; pectolite-hydrogarnet pseudomorphs after an unidentified euhedral phase; chlorite laths; barytolamprophyllite; perovskite; tausonite; diverse Sr-Ba-carbonates; and baryte. The presence of barytolamprophyllite and tausonite are typical of potassic undersaturated alkaline rocks and have never been reported from kimberlite; however, neither feldspar nor feldspathoids are present in P2-West. Micas in fresh and altered rocks are Al2O3- and BaO-poor, and exhibit compositional evolutionary trends towards tetraferriphlogopite rather than kinoshitalite. On the basis of these mineralogical data it is suggested that P2-West represents an unusual lamproite-like intrusion which has undergone extensive hydrothermal deuteric alteration and should not be considered a bona fide kimberlite.

Alumoåkermanite, (Ca,Na)2(Al,Mg,Fe2+)(Si2O7), is a new mineral member of the melilite group from the active carbonatite-nephelinite-phonolite volcano Oldoinyo Lengai, Tanzania. The mineral occurs as tabular phenocrysts and microphenocrysts in melilite-nephelinitic ashes and lapilli-tuffs. Alumoåkermanite is light brown in colour; it is transparent, with a vitreous lustre and the streak is white. Cleavages or partings are not observed. The mineral is brittle with an uneven fracture. The measured density is 2.96(2) g/cm3. The Mohs hardness is ~4.5–6. Alumoåkermanite is uniaxial (–) with ω = 1.635(1) and ε = 1.624–1.626(1). In a 30 mm thin section (+N), the mineral has a yellow to orange interference colour, straight extinction and positive elongation, and is nonpleochroic. The average chemical formula of the mineral derived from electron microprobe analyses is: (Ca1.48Na0.50Sr0.02 K0.01)(Si1.99Al0.01O7). Alumoåkermanite is tetragonal, space group P421m with a = 7.7661(4) Å, c = 5.0297(4) Å, V = 303.4(1) Å3 and Z = 2. The five strongest powder-diffraction lines [d in Å, (I/Io), hkl] are: 3.712, (13), (111); 3.075, (25), (201); 2.859, (100), (211); 2.456, (32), (311); 1.757, (19), (312). Single-crystal structure refinement (R1 = 0.018) revealed structure topology typical of the melilite-group minerals, i.e. tetrahedral [(Al,Mg)(Si2O7)] sheets interleaved with layers of (CaNa) cations. The name reflects the chemical composition of the mineral.

Garnet porphyroblasts in metasediments from Magerøy crystallized during static metamorphism. They display three optical zones, each having characteristic inclusions and chemistry. The compositional zoning is related to prograde metamorphism (an inner zone, 1, and a graphite-bearing zone) and retrogression (the outer zone, 2). Inclusions of two types are present in zone 1: type 1 are equidimensional remnants of the matrix, preferentially included along planes of rapid growth; type 2 are tubular and represent recrystallized quartz grains concentrated along defects in the garnet lattice. The defects are lineage boundaries between growth segments related to screw dislocations on crystal faces. Crystal growth developed at relatively high degrees of supersaturation, but below the supersaturation required for the development of dendrites. The inclusions suggest rapid growth of zone 1, caused by heat flow from an adjacent interkinematic mafic/ultramafic intrusive complex. The graphite-bearing zone crystallized at the metamorphic peak, while the inclusion-free idioblasfic rim probably developed during retrograde metamorphism.

Darwin (1881) was one of the first scientists to formally record that earthworms excrete calcium carbonate granules, with some up to 2 mm in diameter. However, since Darwin’s studies they have received relatively little attention. The function of the granules remains a mystery, but may be related to regulation of Ca, CO2, pH or some other as yet undiscovered metabolic process (Robertson, 1936; Piearce, 1972). There has recently been an increase in research activity focussed on earthworm calcium carbonate granules driven by the work of Canti (Canti, 1998, 2007; Cantian d Piearce, 2003) and largely relating to their potential use in archaeology.

The specimen described by Claringbull and Hey (1952) has been re-examined using electron-microscope, electron-diffraction, X-ray, and dehydration isobar methods. It differs from other specimens in several respects. The basal spacing does not shrink appreciably on dehydration. The principal cleavage is (100) and not (001). The body-centred pseudo-cell of normal dimensions, but the distribution of the weak reflections differs from that found for other specimens. The mechanism of conversion into wollastonite has also been examined.

Almandine garnets in the cordierite-bearing granite of Sweltor Quarry, Dartmoor, contain < 10 mol. % of the spessartine end-member, whilst those in the Lundy granite have c. 10 mol. % spessartine. Experimental work indicates that such compositions can grow in equilibrium with siliceous melts at depths of 18–25 km. This evidence, reaction rims, lack of marked zoning and comparison with garnets in other siliceous calc-alkaline siliceous rocks point to a genesis involving partial melting of the ‘local’ lower crust. A restite origin rather than direct crystallization from magma is favoured but the evidence is equivocal. The Dartmoor granite (Hercynian) is a typical peraluminous late- to post-tectonic S-type granite. The S-type character of the Lundy (Tertiary) granite is revealed by the occurrence of garnet and topaz together with biotite enriched in Rb, Cs and F, despite its close association with Tertiary basic magmatism in an anorogenic setting.

Charoite, ideally (K,Sr,Ba,Mn)15–16(Ca,Na)32[(Si70(O,OH)180)](OH,F)4·nH20, is a rock-forming mineral from the Murun massif in Yakutia, Sakha Republic, Siberia, Russia, where it occurs in a unique alkaline intrusion. Charoite occurs as four different polytypes, which are commonly intergrown in nanocrystallme fibres. We report the structure of charoite-96 (a = 32.11(6), b = 19.77(4), c = 7.23(1) Å, β = 95.85(9)°, V = 4565(24) Å3, space group P21/m), which was solved ab initio by direct methods on the basis of 2676 unique electron diffraction reflections collected by automated diffraction tomography and refined to R1/wR2 = 0.34/0.37. The structure of charoite-96 is related to that of the charoite-90, which was also solved recently. Both structures are composed of three different types of dreier silicate chains running along [001] and separated by ribbons of edge-sharing Ca- and Na-centred octahedra. In the structure of charoite-96, adjacent blocks formed by three different silicate chains and stacked along the x axis, are shifted by a translation of 1/2 c. The shifts involve a hybrid dreier quadruple chain, [Si17O43]18– and a double dreier chain, [Si6O17]10–. In charoite-90 adjacent blocks are stacked without shifts.

At least six separate rare earth and uranium-bearing daughter crystals occur in fluid inclusions hosted by andraditic garnet from the Mary Kathleen REE-U ore skarn, Queensland, Australia. The daughter minerals are particularly high in La, Nd and Ce which reflects the relatively high concentration of these in the bulk ore (La2O3 = 33.5%, Nd2O3 = 9.1% and Ce2O2 = 51.5% of the 2.6 wt. % REE common in the ore). The host garnets themselves contain up to 7600 ppm REE and 5 to 2700 ppm U. The energy-dispersive spectra (EDS) are consistent with the following minerals: a (Y, Ce, U, Ca, Fe, Nb, Ta) mineral; a (Ca, Fe, Ce) carbonate(?) mineral; a (Fe, Ca, Y, Ce, Nb, Ta) mineral; a possible carbonate of La, Mn and Nd; a chlorite of Mn and La as well as a possible chloride or oxychloride of K, Mg, Mn and La. Their occurrence infers that relatively high concentrations of REE and U prevailed in the original, oxidized, concentrated (30–70 wt. % total dissolved salts), high-temperature (550–670°) ore solutions. Their presence as daughter crystals may be due to the fact that CaCl2 is a dominant salt in the solutions and that the latter's solubility was sufficiently high to ‘salt out’ the less soluble REE-U components.

Intermediate members of the grossular–andradite and grossular–uvarovite series are known to display anomalous birefringence, which is inconsistent with the ideal cubic space group of garnet Iad. To determine the reason for such birefringence, the crystal structures of at least 15 samples were refined by different authors including the present ones. The crystals with the value of anomalous birefringence of Δn > 0.001 are normally characterized by partial ordering of the octahedral cations (Al/Fe and Al/Cr for grossular–andradite and grossular–uvarovite series, respectively). This reduces the symmetry to the orthorhombic space group Fddd or even to the triclinic space group I. As is seen from the distribution of occupancies over octahedral sites in the triclinic space group, eight occupancies are grouped into two quartets of similar occupancies, leading to pseudo-orthorhombic crystal structures. The variety of structures with different degrees of pseudo-orthorhombicity is due to the action of the growth dissymmetrization mechanism. Simulations of the optical indicatrix in the point-dipole approximation confirm cation ordering as the main cause of the anomalous birefringence.

Pseudorutile, , has recently been revalidated as a mineral species, and the neotype locality is now South Neptune Island, South Australia. Powder X-ray diffraction data are given on a hexagonal primitive unit cell with a = 2.8667(5) and c = 4.5985(9) Å. Leucoxene, arizonite and proarizonite are considered to be mixtures. Kleberite is considered to be a hydroxylian pseudorutile, .

Determination of the solid-phase arsenic speciation in sediments hosting high-arsenic groundwaters, utilized for drinking and irrigation in Bengal, SE Asia and elsewhere is important in order to understand the biogeochemistry of arsenic. Despite this, there is a relative paucity of speciation data for solid-phase arsenic in such systems, due to preservation difficulties, low arsenic concentrations in the sediments, multiple coordination environments and sample heterogeneity. In this study, X-ray absorption near edge structure spectroscopy was used in conjunction with linear least-squares fitting of model compounds to determine the oxidation state of arsenic in sediments from West Bengal and Cambodia. Whatever the collection and storage method used, substantial oxidation of arsenic was commonly observed over periods of weeks to several months. Sands were particularly susceptible to changes in arsenic oxidation state during storage. Analysis within two or three weeks of collection is therefore recommended, whilst on-site storage under a nitrogen atmosphere immediately after collection is particularly recommended for the preservation of sandy samples. Both muds and sands from West Bengal and Cambodia were dominated by arsenite (As(III)) with <35±10% arsenate (As(V)). Complete oxidation to arsenate was never observed suggesting that a significant proportion of the sedimentary arsenic is inaccessible within crystalline phases. Centrifuging under anaerobic conditions enabled more detailed information about a variety of arsenic coordination environments to be determined.

The present paper summarizes the facts at present known regarding a characteristic effect that is often produced in the fresh plagioclase felspars of igneous rocks by thermal metamorphism—namely the development of a special type of cloudiness caused by the appearance of minute inclusions. Reference is also made to certain wel|-known rocks in which the clouding of plagioclase felspars has been described without any suggestion that the peculiarity of the felspars is connected with thermal metamorphism.

Mineral sequestration is among several promising methods of CO2 reduction. It involves incorporation of CO2 into a solid phase via precipitation of carbonate minerals. A prerequisite to carbonate precipitation is the availability of aqueous metal cations and a network of porous media for fluid flow and water-rock interactions. The Hellisheidi-Threngsli lava field in SW Iceland comprises ideal conditions for studying the feasibility of permanent CO2 storage as minerals in basaltic rocks. In this paper we report on a tracer test conducted between two wells at the Hellisheidi-Threngsli site to characterize the physical properties of the main aquifers. The results suggest that most of the water flow between the wells is through an homogenous thick layer with high tortuosity along flow paths and a high reactive surface area for water-rock interactions.

Anorthite megacrysts are common in basalts from the Japanese Island Arc, and signally rare in other global fields. These anorthites are 1 to 3 cm in size and often contain several corroded Mg-olivine inclusions. The megacrysts generally range from An94Ab4Ot2 to An89Ab6Ot5 (Ot: other minor end-members, including CaFeSi3O8, CaMgSi3O8, AlAl3SiO8, □Si4O8) and show no chemical zoning. They often show parting. Redclouded megacrysts contain microcrystals of native copper with a distribution reminiscent of the shape of a planetary nebula. Hydrocarbons are also present, both in the anorthite megacrysts and in the olivines included within them. Implications of lateral variations in the Fe/Mg ratio of the included olivines, in Sr-content and in Sr-isotope ratio of the anorthite megacrysts with respect to the Japanese island arc, relate to mixing of crustal components and subducted slab-sediments into the basaltic magmas.

Igneous graphite, a rare constituent in terrestrial mafic and ultramafic rocks, occurs in three EH and one EL enstatite chondrite impact-melt breccias as 2–150 µm long euhedral laths, some with pyramidal terminations. In contrast, graphite in most enstatite chondrites exsolved from metallic Fe-Ni as polygonal, rounded or irregular aggregates. Literature data for five EH chondrites on C combusting at high temperatures show that Abee contains the most homogeneous C isotopes (i.e. δ13C = −8.1 ± 2.1‰); in addition, Abee's mean δ13C value is the same as the average high-temperature C value for the set of five EH chondrites. This suggests that Abee scavenged C from a plurality of sources on its parent body and homogenized the C during a large-scale melting event. Whereas igneous graphite in terrestrial rocks typically forms at relatively high pressure and only moderately low oxygen fugacity (e.g., ∼ 5 kbar, logfO2 ∼ −10 at 1200°C), igneous graphite in asteroidal meteorites formed at much lower pressures and oxygen fugacities.