Abundant microfossils have recently been discovered in the late Palaeoproterozoic Changzhougou Formation, Changcheng Group, Jixian, north China. The Changzhougou microbiota consists dominantly of sphaeromorph acritarchs and some osillatoriacean cynobacterial filaments. The micro-fossils were recovered from shales and are compressed on bedding surfaces. The sphaeromorph acritarchs, ranging from 8.4 to 237.8 μm in diameter, are morphologically simple. On the basis of their dimensions and morphological considerations, the sphaeromorph acritarchs are interpreted as probably representing the resistant, reproductive cysts of unicellular protists. This assemblage is evidently among the oldest known clastic-facies microbiotas in the geological record and provides evidence of protist eukaryotes being extant at 1848 Ma.

A likely example of biochemical evolution in the nautiloids is demonstrated, based on X-ray fluorescence analysis of the Sr content of unaltered shells.

Alternating zones of normal and reverse natural permanent magnetization, each comprising about twenty-five flows, have been found in the Tertiary and Quaternary plateau basalt series of Iceland. The techniques for measuring this permanent magnetization are discussed and some results shown. It is suggested that zones of normal and reverse magnetization may be useful for correlation purposes in volcanic districts. Some other possible applications of rock magnetism are mentioned.

A preliminary geochemical investigation of Silurian (Llandovery) basinal mudstones (turbidites and hemipelagites) from the Southern Welsh Basin is described. Turbidite mudstones show higher concentrations of Fe2O3, MgO, TiO2, MnO, LOI, Zn and Zr than laminated hemipelagites. This is consistent with the observed higher concentrations of chlorite and Ti-bearing minerals in turbidite mudstones. Laminated hemipelagites show higher values of REEs (Ce and La), concentrated within authigenic monazites, and Ni, As, Cu and Pb within sulphide minerals (pyrite and galena) reflecting the influence of primary organic carbon levels and anoxic bottom waters on early diagenesis. Deposition of hemipelagites under oxidizing conditions is reflected in lower concentrations of authigenic sulphide mineral hosted elements compared with laminated hemipelagic lithologies. There is a distinct geochemical difference between mudstones of easterly and southerly provenance in the Southern Welsh Basin. This is shown for both turbidites and hemipelagites. The differences are due to the increased input of illite and the chemical elements associated with this mineral (K2O, A12O3, Rb and Ba). Turbidite mudstones sourced from the south show increased levels of heavy minerals, especially those associated with Ti-rich minerals. There is also an increase in elements associated with detrital monazites: Th and Y. The hemipelagites show higher values of REE and chalcophile elements consistent with their more reduced nature.

Basal Turonian Ezeaku Sandstone ridges along the Cenomanian hiatus in Afikpo area contain sandstone pebbles, cobbles, and boulders randomly distributed in nearly all the coarsening upward subfacies of the host units. Contacts with the host sandbody are sharp and, in places, lined with solution grooves. Generally, the angular to subrounded clasts have their 2 mm rims ferruginized, are fine to coarse grained and very strongly bioturbated. They are compositionally and texturally more similar to the adjacent Albian Asu River Group sandunits. These characteristics suggest an extrabasinal origin for these marine sandstone clasts. Albian Asu River Group sediments uplifted by the Cenomanian deformation are the most likely source. The general absence of similar clasts towards the eastern palaeostrandline where the primary Cretaceous source rocks lay is consistent with the interpretation. The remarkable parallelism between the trend of the clast outcrops and the axis of the Santonian anticlinorium (NE–SW) suggests the same axial direction for both tectonic phases.

In the carbonate-siliciclastic strata of West Gondwana (e.g. in the Montagne Noire, France), the aftermath of the mid Languedocian (mid Cambrian) regression is characterized by a late Languedocian major turnover of trilobite families and a Furongian–early Tremadocian radiation related to the stepwise immigration of trilobite invaders from East Gondwana under persistent transgressive conditions. The scarcity of upper Languedocian fossil accumulations in clayey substrates has inspired the sampling of the palaeogeographically most distal parts of the Iberian Chains (Spain), where diagenetic dissolution of ubiquitous hexactinellid sponge spicules has favoured the formation of siliceous concretions. These have yielded the trilobites Peronopsis cf. insignis, Oidalagnostus trispinifer, Proampyx difformis (= Proampyx aculeatus), Bailiaspis? glabrata (= Holocephalina agrauloides, by ontogeny), Holasaphus cf. centropyge and a paradoxidid gen. et sp. indet. Despite preservation and sampling biases, the identification of this taphonomic window in offshore clayey substrates of West Gondwana allows the recognition of a strong biogeographical link with Baltica, and the correlation of the global Guzhangian Stage and the Solenopleura? brachymetopa Zone of Scandinavia with part of the Mediterranean upper Languedocian Substage.

Late to post-Variscan sedimentary basins of Sardinia were influenced during Pennsylvanian to Permian times by two main tectono-sedimentary cycles: a Pennsylvanian to Cisuralian cycle represented mainly by dark limnic deposits, overlain by a Guadalupian to a possibly Lopingian cycle, mostly characterized by red-bed deposits. Lacustrine waterbodies developed in some sedimentary basins that were filled with siliciclastic to frequently early silicified carbonate deposits, depending on the climate and environmental conditions, landscape morphology and tectonic regime. The limnic successions of the lower tectono-sedimentary cycle were deposited in permanent, tens of metres deep lakes in deep, narrow tectonic strike-slip basins under a temperate to warm-humid climate. They started as lakes with terrigenous sedimentary input and developed minor carbonate deposits mainly at the end of their story. Conversely, the red-bed successions of the upper cycle were deposited in ephemeral, shallow playa lakes related to wider basins in an extensive alluvial plain under a hot and arid climate. Here, the siliciclastic sediments are intercalated with thin carbonate beds that are typical of a high evaporation rate. The evolution of the lake type could be related not only to a major climatic shift, but also to the changing morphotectonic conditions of the Variscan chain influencing the local microclimate. Comparisons with coeval successions in the Provence Basin, the Massif Central Aumance basin (France) and the Saar–Nahe Basin (Germany) show both similarities and differences between the basins.

New Palaeogene vertebrate localities were recently reported in the southern Dakhla area (southwestern Morocco). The Eocene sediment strata crops out on cliffs along the Atlantic Ocean coast. Vertebrate remains come from five conglomeratic sandstone beds and are principally represented by isolated teeth belonging to micromammals, selachians and bony fishes, a proboscidean assigned to ?Numidotherium sp. and many remains of archaeocete whales (Basilosauridae). From fieldwork five lithostratigraphic sections were described, essentially based on the lithological characteristic of sediments. Despite the lateral variations of facies, correlations between these five sections were possible on the basis of fossil-bearing beds (A1, B1, B2, C1 and C2) and five lithological units were identified. The lower part of the section consists of rhythmically bedded, chert-rich marine siltstones and marls with thin black phosphorite with organic matter at the base. The overlying units include coarse-grained to microconglomeratic sandstones interbedded with silts, indicating deposition in a shallow-marine environment with fluvial influence. The natural remanence magnetization of a total of 50 samples was measured; the intensity of most of the samples is too weak however, before or after the first step of demagnetization. The palaeomagnetic data from the samples are very unstable, except for eight from three similar sandstone levels which show a normal polarity. Matched with biostratigraphic data on rodents, primates, the selachian, sirenian and cetacean faunas, the new carbon isotope chemostratigraphy on organics (1) refines the age of the uppermost C2 fossil-bearing bed to earliest Oligocene time and (2) confirms the Priabonian age of the B1 to C1 levels.

It requires but little imagination to conceive that a very slight subsidence of the country in North Wales lying between the Vale of Clwydd and the estuary of the River Dee would convert it into a peninsula consistingof Carboniferous rocks skirting to the north, and to the east a strip of Silurian ground. The backbone of this peninsula is composed of Lower Carboniferous rocks, forming the high range which starts from the bold cliffs that border the sandy flats of the north shore of Flint from Dyserth to Talacre. Stretching southwards by way of Halkyn Mountain, Moel Findeg, Nerquis Mountain to Minera and Llangollen, this range, in the main, forms ani anticline, off whose eastern flanks the higher divisions of the Carboniferous system dip in natural sequence towards the River Dee.

Seventeen Connemara pelites have been chemically and modally analysed and a garnet, a staurolite, and a biotite from them chemically analysed. The results show that these pelites are rather poor in silica and rich in alumina and total iron. It is believed that this was an original feature of the composition.

The composite dyke at An Cumhann, Arran consists of a central unit of quartz-feldspar porphyry flanked by narrow marginal dolerites containing xenocrysts of quartz, plagioclase and alkali feldspar identical to the phenocrysts in the porphyry. The chemistry of the marginal dolerites indicates that they formed by the crystallization of a hybrid magma produced at depth by the incorporation of the porphyritic acid magma in a basic liquid. During the intrusion of the hybrid magma, flow caused a differential distribution of the xenocrysts across the initial basic dyke. Subsequent intrusion of the quartz-feldspar porphyry magma along the still unconsolidated centre of the basic dyke produced the wide central unit. A similar origin is proposed for other composite intrusions of the same type in the region. Whilst it is unlikely that the coexistence of the highly contrasting magmas necessary for the formation of these intrusions is entirely coincidental there is little likelihood that the two liquids were related as members of the same fractionation series.

Aeolian dust deposits from continent and ocean have been extensively investigated to reflect past changes in source aridity and atmospheric circulations. Aeolian flux (AF) as a quantitative dust proxy has been widely used in both palaeoenvironmental reconstruction and numerical simulation. However, available AF data on the Chinese Loess Plateau (CLP) is too limited to assess the temporal–spatial variations at glacial–interglacial timescales, and therefore cannot be used as robust input parameters in palaeoclimate models. Here we investigate eight loess profiles along two N–S-aligned transects on the CLP to quantitatively estimate the AF variations over the last glacial–interglacial cycle. We first establish a refined chronological framework based on optically stimulated luminescence chronology and pedostratigraphic correlation. AF was then estimated by multiplying the sedimentation rate and bulk density. The results show that the AF increases from 2–18 g cm−2 ka−1 in the southeastern CLP to 14–105 g cm−2 ka−1 in the northwestern CLP. At glacial–interglacial scales, the AF varies from 2–20 g cm−2 ka−1 during the last interglacial to 8–105 g cm−2 ka−1 in the last glaciation. Due to more spatial coverage and better age constraints, our AF data can be used to refine other AF datasets and to improve the proxy–model comparison.

Burlingia balangensis sp. nov. from the lower Cambrian of South China represents the earliest species of this genus, and suggests that the genus may have originated in South China. A revision of the genus shows that B. primitiva and B. obscura can be used in order to indentify the base of the Cambrian Stage 5 when other trilobites are absent because their last appearance datum (LAD) coincides with the first appearance datum (FAD) of Oryctocephalus indicus. Available palaeogeographic and palaeoclimatic models suggest five major palaeocurrents during Cambrian times which could control the migration patterns of the Burlingia clade from South China to Baltica.

The Aguablanca stock is a Variscan mafic pluton located in the Ossa-Morena zone, southern Iberian Massif, hosting an unusual Ni–Cu–PGE mineralization associated with magmatic breccia pipes which intruded its northern part. The emplacement of the Aguablanca stock and the mineralized breccia pipes are related to the activity of the Cherneca ductile shear zone, a Variscan sinistral shear zone that favoured magma ascent through the upper crust. A detailed gravity study has been carried out in order to investigate the 3D geometry of the Aguablanca intrusion and to get insights about the emplacement mechanism and tectonic controls of the mineralization. The three-dimensional gravity modelling shows that the stock has an inverted drop geometry with a feeder zone in contact with the Cherneca ductile shear zone. The inferred orientation of the feeder zone suggests that the emplacement probably took place along an open tensional crack formed within the strain field of the adjacent Cherneca ductile shear zone. The modelling of the breccia pipes hosting the Ni–Cu–PGE ore shows that they are included inside the feeder zone, thus their emplacement is probably controlled by successive opening events of this tensional crack.

The regional strike of the bedding and foliation is NW but most of the folds and lineations plunge roughly SW. Lineations that resemble grain (longrain) seem to be usually parallel to the steeply plunging fold axes. This structural pattern occupies more than 2,000 km2. The formation of this pattern of folds was preceded and succeeded by regional folding along horizontal axes.

Various genetic models have been proposed for the supergiant Proterozoic Broken Hill Pb–Zn–Ag deposit largely based on geological and geochronological evidence. Here we present Zn, Cd and S isotope compositions as well as Zn/Cd ratios of sphalerite from Broken Hill and minor Broken Hill-type deposits (Australia) to help constrain these models but focus on syngenetic and magmatic–hydrothermal processes, since epigenetic models can be rejected because the orebodies were deformed and metamorphosed by the Olarian Orogeny. Values of δ34SVCDT, δ66ZnAA-ETH and δ114CdNIST SRM 3108 for sphalerite from Broken Hill range from +0.27 to +4.73 ‰, −1.15 to +0.46 ‰ and −0.48 to +0.01 ‰, respectively, while those for the smaller Broken Hill-type deposits range from −5.11 to +1.28 ‰, −0.97 to +0.10 ‰ and −1.02 to +2.59 ‰, respectively. By combining published S isotope data of sulfides from the Broken Hill district with those obtained here, the sources of sulfur via thermochemical sulfate reduction, bacterial sulfate reduction and a magmatic origin cannot be distinguished. However, when the S isotope compositions are considered along with the broad range of Cd and Zn isotope data for sphalerite, which are among the lightest and heaviest yet reported for a sulfide deposit, the isotopic datasets are consistent with low-temperature biogenic processes associated with syngenetic deposition of sulfides. Cadmium isotope compositions when coupled with Zn/Cd ratios of sphalerite have previously been used to classify Pb–Zn deposits, including low-temperature, high-temperature and exhalative ores. However, the Zn/Cd ratios of sphalerite from Broken Hill cannot be used for such classification purposes.

The Palaeozoic Uralian orogen formed by accretion of island arcs and microcontinents along the eastern margin of the East European platform. In the middle Urals, a promontory of the East European platform, the Ufaley Complex experienced eclogite facies conditions followed by an amphibolite facies overprint. The Verkniy Ufaley intrusion crosscuts the amphibolite facies foliation in the East Ufaley Complex and thus postdates the two metamorphic events. A concordant U–Pb age of 316±1 Ma obtained on magmatic titanite dates the intrusion of the pluton and provides a minimum age for subduction and subsequent amphibolite facies metamorphism of the East European continental margin. Zircon yields discordant age data that reflect the involvement of Proterozoic crustal sources.

The Portsoy–Duchray Hill Lineament has been widely quoted in the literature as a major zone of discontinuities, running from Portsoy on the Banff coast to the Duchray Hill area in Perthshire. A review of the evidence indicates that there is no single structural entity running from Portsoy to Duchray Hill; the term ‘Portsoy-Duchray Hill lineament’ should be avoided. There are, however, significant along- and across-strike variations in geological history across a zone which extends from Portsoy to the Cabrach (the ‘Portsoy Line’). Certain elements can be identified also in areas further south, e.g. the Coyles of Muick shear zone and Glen Doll fault.

The Portsoy Line was initiated as a zone of syn-depositional faulting, with resulting facies variations similar to those seen across the Glen Doll fault. The Portsoy Line was reactivated as a ductile shear zone during Caledonian orogenesis, while the Glen Doll fault is a later, more brittle, structure. The shear zone from Portsoy to the Cabrach forms the western branch of a system of shears which acted to focus syn-orogenic basic magmatism, and differential movement during post- metamorphic uplift. The Coyles of Muick shear zone is the most southerly example of the system of shears, and there is probably a transfer zone along Deeside between it and the Portsoy-Cabrach shear zone, now obscured in part by the Ballater Granite. The focused shear zones serve to delineate the Buchan area, with its low pressure metamorphism and distinctive structural style, from areas to the south and west where the structural level was deeper, and deformation more pervasive.

Basic hornfelses occurring at the contact of slates and olivinenorite are ascribed to influx of Ca, Mg, Fe, Ti, Mn, and P from the gabbro magma into the sedimentary rocks. This kind of basic front, unlike those postulated for acid bodies, has a basic back.

Regional gravity and aeromagnetic data of Wales have been processed using a variety of techniques. Image processing has greatly assisted qualitative interpretation, whilst automated procedures have provided additional quantitative information. The shaded relief images emphasize gradients in the potential fields, and are useful for displaying strong linear features. The Euler deconvolution method produces plotted solution maps, which define the position of the source of the gravity and magnetic anomalies. Euler solution maps of Wales and the adjacent continental shelf are presented for the first time. These maps are interpreted in relation to the known geology, with special emphasis on the Lower Palaeozoic Welsh Basin. It is proposed that the Euler solutions define a network of fault-bounded blocks within the Precambrian basement.