Two generations of sulphide-hosted platinum-group element mineralization occur in the West Sgaorishal ultramafic plug, Rum. Disseminated Cu and Ni sulphides around the margin of the plug host a restricted platinum-group mineral assemblage that is dominated by Pd bismutho-tellurides and sperrylite (PtAs2) with subordinate electrum (AuAg), froodite (PdBi2) and unidentified Pt–Bi–Te phases. Later sulphide-rich dykes cross-cut the plug and host an assemblage dominated by Pd bismutho-tellurides, sperrylite and locally very abundant paolovite (Pd2Sn). Whole rock combined platinum-group element+Au concentrations are proportional to the sulphide abundance with slightly elevated values in disseminated sulphide lithologies (>400 ppb) and very high values (>2000 ppb) in the sulphide-rich dykes. Both generations have relatively flat chondrite-normalized plots indicating a primitive magmatic source. Negative δ34S values (−9.2 to −18.3 ‰) indicate that the disseminated mineralization is due to contamination probably derived from Jurassic sedimentary rocks leading to sulphur saturation and collection of platinum-group elements. The sulphide-rich dykes must have entrained a platinum-group element-rich sulphide liquid collected from a much larger volume of magma. The presence of platinum-group elements and sulphide-rich dykes with δ34S values between −10.8 and −15.0 ‰ indicates that parts of the Rum Layered Suite became sulphur saturated through magmatic contamination. It appears likely that platinum-group element mineralization styles within the southern North Atlantic Igneous Province are diverse and may be present in a wider variety of mineralogical associations than previously recognized.

Carbon and oxygen isotope data from a succession of Cretaceous (Barremian–Cenomanian) age recovered from the Pacific Ocean (DSDP site 463) are presented. The carbon isotope curve reveals a large isotope excursion within the early Aptian where δ13C values reach ~4.8‰ in the L. cabri–G. ferreolensis foraminifera zone. A decrease in δ13C values is observed at the base G. algerianus zone, before a return to more positive values at the top of the G. algerianus–T. bejaouaensis zone. The pronounced early Aptian positive event is preceded by a large negative isotope excursion, confined to the G. blowi zone. Synchronous with this excursion are increased total organic carbon values and increases in Mn and Fe concentrations. Integrated biostratigraphic and magnetostratigraphic data, together with the carbon isotope profile, suggest that the organic-rich units of site 463 are correlatable with Oceanic Anoxic Event 1a. The input of isotopically light volcanic CO2 in concert with the intensification and upwelling of intermediate water enriched in 12C could account for the observed trends. A potential trigger may have been the destabilization of the water column and the prodigious CO2 emissions associated with hydrothermal activity and the emplacement of the Ontong Java Plateau. Coupled with faunal evidence, the subsequent positive carbon isotope excursion is interpreted to be resulting from high, but decreasing, productivity and possibly increasing ocean stratification resulting in strong carbon isotopic gradients and 13C-enriched surface waters. The decrease in δ13C within the G. algerianus zone is coincident with more positive δ18O values. If these are interpreted in terms of temperature this interval may be characterized by a period of cooling and possibly a waning of Corg cycling. A return to lower δ13C values during the middle Albian is considered to be related to the increased influence of upwelling, as opposed to a waning of Corg cycling. Upwelling introduced isotopically light carbon to the surface, arresting the stratified oceanic conditions.

A new Middle Permian locality in northern Johore, Peninsular Malaysia, yields a small-sized, but compositionally unique, brachiopod fauna consisting of eight species: Pseudoleptodus sp., Caricula cf. salebrosa Grant, Neochonetes (Nongtaia) aff. arabicus (Hudson & Sudbury), Karavankina sp., Transennatia cf. insculpta (Grant), Hustedia sp., Orthothetina sp., and martiniid indet. The first four genera are new records for Malaysia; in particular, the rare taxa Pseudoleptodus and Caricula characterize the fauna. The brachiopods occur together with the ammonoid Agathiceras sp., the nautiloid Foordiceras? sp., bivalves, and crinoid stems. The locality belongs to the East Malaya terrane of the Cathaysian biotic region, but some affinities to species of the Sibumasu province are recognized. The Malaysian forms of Pseudoleptodus, Caricula and Transennatia are similar to those of the Ratburi Limestone (southern Thailand). A Roadian–early Wordian age is interpreted for the Johore fauna. The similarity of brachiopods reported here with those from the Ratburi Limestone suggests that there was species interchange or one-way migration between shallow waters of East Malaya and Sibumasu across the main Palaeo-Tethys. The Tethyan seaway between the two terranes must have been narrower than previously interpreted by some authors to allow such faunal traffic during the Roadian–Wordian time period.

Fifty new Nd isotope analyses are presented from the North Bay area of the Grenville Province in Ontario. These data are used to map the extent of an allochthonous Grenvillian terrane which is an outlier of the Allochthonous Polycyclic Belt of the Grenville Province. Amphibolite facies orthogneisses from the allochthonous terrane have depleted mantle Nd model ages (TDM) below 1.8 Ga, whereas the gneisses of the structurally underlying parautochthon almost invariably have model ages above 1.8 Ga. The distribution of model ages is consistent with the distribution of distinct types of metabasic rock, used by other researchers as the criterion for recognizing rocks of the allochthonous and parautochthonous belts of the Grenville Province. The agreement between these different types of evidence demonstrates that Nd isotope mapping is a reliable and powerful tool for mapping terrane boundaries in high-grade metamorphic belts.

Graptolites from more than 60 horizons in the basinal Caradoc succession of southwest Wales, between Fishguard and Cardigan, allow recognition of the multidens, clingani and linearis biozones. The biostratigraphy permits recognition of major differences in the sedimentary rock-sequence north and south of structures associated with the Fishguard–Cardigan Fault Belt. The Penyraber Mudstone Formation, disconformably overlying the Fishguard Volcanic Group (Llanvirn), is partly of multidens Biozone age. It is succeeded south of the Newport Sands Fault by the Cwm yr Eglwys Mudstone Formation of clingani to linearis biozones age. North of the fault the Cwm yr Eglwys Mudstone Formation is replaced laterally by the northwards-thickening, sandstone turbidite-dominated Dinas Island Formation (clingani and linearis biozones). Graptolite stratigraphical distribution indicates that Dicranograptus clingani occurs only rarely within the caudatus Subzone of the clingani Biozone and that Climacograptus antiquuss.l. also does not range above the lower part of the clingani Biozone. The first occurrence of Dicellograptus morrisi, within the upper clingani Biozone, confirms its value as a marker for the morrisi Subzone, and is associated with the first occurrences of Diplacanthograptus dorotheus and Normalograptus minimus. Dicellograptus flexuosus, used to indicate the morrisi Subzone elsewhere, occurs throughout the clingani Biozone in the Cardigan area. The linearis Biozone is recognized by Climacograptus tubuliferus. Oxic bottom conditions in early and early mid-Caradoc times largely precluded the influx of, or preservation of, graptolite faunas in the Penyraber Mudstone Formation. Anoxic mudstones of the Cwm yr Eglwys Mudstone and Dinas Island formations preserve graptolite assemblages of 21 and 26 species, signalling strong open marine influences which persisted in this area until late Caradoc times. This contrasts with the shelfal faunas in the Whitland area (south Pembrokeshire), where the late Caradoc is dominated by low-diversity Normalograptus-dominated assemblages.

New U–Pb zircon dating yields a crystallization age of 458±3 Ma for the largely gabbroic Grøndalsfjell Intrusive Complex in the Gjersvik Nappe of the Caledonian Upper Allochthon in Scandinavia. This is identical, within error, to the age of the adjacent Møklevatnet Complex that is dominated by quartz monzodiorite (456±2 Ma), and the two intrusive suites may be regarded as members of a composite intrusion here referred to as the Nesåa Batholith. Mafic members of this calc-alkaline batholith are characterized by slightly positive εNd–εSr values, marked enrichment of the light rare earth elements and high Th/Yb ratios suggestive of a subduction-modified mantle source. The I-type granitoids have similar isotope values and highly fractionated rare earth element patterns, and are interpreted as products from partial melting of garnet-bearing mafic rocks. The Nesåa Batholith intruded a previously deformed, 483 Ma or older, metavolcanic sequence of oceanic arc affinity. The margins of the pluton show evidence for synkinematic emplacement, which is tentatively interpreted in terms of magma ascent controlled by deep-seated shear zones. Further uplift and exhumation of the crystallized plutons was followed by rapid deposition of batholith-derived conglomerates and arkoses in a marginal basin represented by the Limingen Group. The age of the Nesåa Batholith fills the gap in reported ages for Caledonian magmatism, between the Early to Middle Ordovician, oceanic to continental margin type, arc sequences of Laurentian palaeotectonic affinity, and the Late Ordovician–Early Silurian batholith complexes of interpreted Laurentian margin affinity. It is interpreted as an early phase of the more extensive plutonism recorded in the Bindal Batholith of the Uppermost Allochthon to the west. Our model implies that the Early Ordovician oceanic arc sequences of the Gjersvik Nappe were deformed and accreted on to Laurentian margin lithologies prior to Late Ordovician times. This composite crustal assemblage was the source for the voluminous quartz monzodioritic intrusions of the Nesåa Batholith, which formed by partial melting due to ponding of subduction-related mantle derived mafic magmas either within or at the base of the active continental margin.

The Bossòst dome is an E–W-trending elongated structural and metamorphic dome developed in Cambro-Ordovician metasedimentary rocks in the Variscan Axial Zone of the central Pyrenees. A steep fault separates a northern half-dome, cored by massif granite, from an E–W-trending doubly plunging antiform with granitic sills and dykes in the core to the south. The main foliation is a flat-lying S1/2 schistosity that grades into a steeper-dipping slaty cleavage at the dome margins. Three major deformational and two metamorphic phases can be differentiated. S1/2 schistosity is an axial planar cleavage to W-vergent recumbent folding that probably occurred in mid-Westphalian time. Peak regional metamorphism M1 is characterized by static growth of staurolite and garnet following thermal relaxation of the previously thickened crust. Strong non-coaxial deformation recording uniform top-to-the-SE extension during D2a is preserved in staurolite–garnet schists in a 1.5 km thick, shallowly SE-dipping zone in the southeastern dome. A 500 m thick contact aureole (M2) was imprinted on the regionally metamorphosed rocks following the intrusion the Bossòst granite during D2b. More coaxial deformation prevailed during synkinematic growth of M2 phases in the inner part of the contact aureole around the northern part of the dome, where it obliterated D2a fabrics. Progressive non-coaxial deformation continued in the southeastern antiform and is recorded by late-synkinematic growth of cordierite. Successive overprinting of the M1 staurolite–garnet assemblage by andalusite and cordierite of M2 is preserved in the southern part. The assemblage muscovite+cordierite+staurolite+biotite is considered metastable, given the low Mn and Zn contents of staurolite and cordierite, and interpreted as the result of prograde metamorphism during decompression. P–T conditions during M2 were approximately 3 kbar and 600 °C. Pervasive crenulations and mesoscopic to regional southerly verging folds are the result of D3 NNE–SSW compression post-dating ductile deformation and contact metamorphism. Polymetamorphic assemblages of the Bossòst dome preserve a regionally confined zone of ESE-directed extensional shearing within an overall N–S compressional setting. Exact timing of extensional shearing is not known, but can be constrained by recumbent folding during the mid-Westphalian and granitic intrusions, which confine it to Late Carboniferous time (c. 305 Ma). Crustal-scale flat-lying extensional shear zones with similar orientation and time frame are observed in the Hospitalêt massif of the eastern Axial Zone. This suggests that crustal extension, though probably restricted by regional strain partitioning over orthogneiss or intruding granitic bodies within an overall compressive setting, was not uncommon in Late Carboniferous time in the Axial Zone of the Pyrenees.