The Fulu iron formation (IF) is an iron-rich unit in the Neoproterozoic glacial successions, South China. The major element data suggest that the iron sources of the Fulu IF are derived from binary mixing from hydrothermal and detrital loads. The Fulu IF is characterized by slightly positive Eu anomalies similar to other Neoproterozoic IFs, indicating that a high-temperature hydrothermal input may contribute little to Neoproterozoic IFs. A shift from non-existent to slightly negative Ce anomalies of the Fulu IF indicates that the IF precipitated across an iron chemocline separating a weakly oxic surface ocean from an oxygen-depleted deep ocean.

The Maestrat basin was one of the most subsident basins of the Mesozoic Iberian Rift system, developed by a normal fault system which divided it into sub-basins. Its Cenozoic inversion generated the N-verging Portalrubio–Vandellòs fold-and-thrust belt in its northern margin, detached in the Triassic evaporites. In the hinterland, a 40 km wide uplifted area, in the N–S direction, developed, bounded to the N by the E–W-trending, N-verging Calders monocline. This monocline is interpreted as a fault-bend fold over the ramp to flat transition of the E–W-trending, N-verging Maestrat Basement Thrust, and also indicates the transition from a thick-skinned (S) to a thin-skinned (N) style of deformation. This paper presents a kinematic evolutionary model for the northern margin of the basin and a reconstruction of the Maestrat Basement Thrust geometry, generated by the inversion of the Mesozoic normal fault system. It contains a low-dip ramp (9°) extended southwards more than 40 km, attaining a depth of 7.5 km. As this thrust reached the Mesozoic cover to the foreland, it propagated across the Middle Muschelkalk evaporitic detachment, generating a nearly horizontal thrust which transported northwards the supra-salt cover, and the normal fault segments within it, for c. 11–13 km. The displacement of the basement in the hanging-wall of the low-dip basement ramp generated the 40 km wide uplifted area, while the superficial shortening was accumulated in the northern margin of the basin – which contains the thinnest Mesozoic cover – developing the Portalrubio–Vandellòs fold-and-thrust belt.

Evidence from Mull and Ardnamurchan is brought forward to show that the injection of cone-sheets is accompanied by a vertical lifting of the upper wall. This confirms Anderson's explanation. It is argued that the fracturing and injection are of a quite sudden character and that it is in the nature of the process that no evidence from recent volcanoes has yet been obtained of contemporary cone-sheet injection.

The Châteaupanne Unit belongs to the South Armorican domain of the Armorican Massif (France), which is part of the Variscan belt. This unit includes two Lower Devonian plant levels and one of them corresponds to the Basal Member of the Chalonnes Formation. A sedimentological and palaeontological analysis of these fossiliferous deposits from the Châteaupanne quarry (Montjean/Loire, Maine et Loire, France) is presented here for the first time. The age determination based on palynology indicates that the locality records the earliest occurrence of plant megafossils in the Armorican Massif. Their presence suggests an emergence event that has never been described before. Our study highlights the promising potential of the Basal Member of the Chalonnes Formation to aid in understanding these occurrences, and provides new insights into the history of the Variscan belt.

The differentiated dyke rocks of Mer Mundwara comprise a subalkaline series which includes basalts and dolerites, and an alkaline series which includes theralites, porphyritic alkali syenites and nepheline syenites. These intrude into the coarse grained Precambrian granites which, in their turn, are subjacent bodies in the Aravalli system of metamorphic complex of archaean age. Absolute age of basic volcanics is 56±8 Ma, thus relating their emplacement to Deccan Trap volcanism in the Cretaceo-Eocene times in Central and Western India. Petrochemical characteristics of the basic rocks exemplify an alkaline character and so indicate that the basaltic magma of Mer Mundwara is tectonically and genetically different from the Deccan basalts which are in the main tholeiitic. The geological setting, petrography and major and minor element chemistry (Na > K and abundance of Nb, Co, Sn and V) relegate the dyke rock suite to the alkaligabbroic formations of Borodin (1974) with their parent magmatic source in the upper mantle. The alkaline igneous rocks of Mer Mundwara strongly suggest a possible occurrence of rare earths, niobium, zirconium and fluorine in industrial concentrations and also thorium and phosphorus.

Single grains of detrital white mica from two different synorogenic sediments in the Southern Urals were analysed using the in situ ultraviolet laser ablation Ar–Ar dating technique to discriminate between age signatures associated with a high-pressure signal (phengites) from those related to muscovite only. Two disparately aged sandstone formations of Neoproterozoic (Upper Vendian) and Upper Devonian (Famennian) age were formed by the erosion of high-relief source areas with contemporaneously exhumed high-pressure rocks. A bimodal distribution of ages and chemical compositions can be detected in the two detrital populations. There is no age overlap between the two populations, reflecting completely different source areas containing high-pressure rocks of different ages. Within the Upper Vendian sandstones, detrital white mica from a 571–609 Ma age group is phengitic in composition (Si 3.3–3.41 per formula unit), while an older 645–732 Ma age group is comprised of muscovite composition grains only. The first group is compatible with the time of late exhumation and emplacement of a source area containing high-pressure rocks, the Neoproterozoic Beloretzk terrane. The older age range is compatible with a long history of cooling and the allochthonous nature of this terrane. Detrital white mica from the Famennian sandstones (Zilair Formation) comprises one age group (342–421 Ma) containing phengite (Si 3.21–3.39 per formula unit) and muscovite, and a second group (446–496 Ma) containing muscovite only. While the derivation of the second group cannot be correlated with any as yet known regional data, the first age group indicates the earliest arrival of high-pressure rocks at the surface along the suture zone after Late Devonian arc–continent collision.

Remapping of parts of the Galway granite has shown that over most of its outcrop it is a homogeneous adamellite. A steeply dipping belt of basic rocks borders the intrusion on the north where there is a reaction zone between adamellite and basic rock. A similar but gently dipping belt of basic rocks overlies the granite to the west. In the south, where there is no reaction zone, the granite intrudes and hornfelses a group of pillow lavas, greywackes, and conglomerates. The structural features of the northern border indicate that the granite has been emplaced as a diapir and radial fractures in the north-east border further indicate that the granite and its basic envelope moved upward and outward together into the Connemara schists.

During the summer of 1929 members of the International Summer School of Geology and Natural Resources, Princeton University, had the opportunity of examining with Mr. E. B. Bailey geological sections in the South-west highlands of Scotland and assisting in the determinations of tops and bottoms of beds in certain critical areas. The subdivision of the series into formations and the distribution of these formations were already for the most part known, but some important details of the structural interpretation were in doubt. In 1924, Thorolf Vogt, after visiting the area, stated that he had determined the order of succession in parts of the folded series; but these determinations by Vogt and their implications had not been verified or accepted by Mr. Bailey by the early part of 1929. Detailed observations made by the Princeton party in 1929, on strata which admitted of top and bottom determinations on the basis of cross-bedding, channelling and texture gradations, confirmed and extended the findings of Vogt; and Mr. Bailey is now in a position to restate the structural interpretation of the South-west Highlands making use of satisfactorily determined sequences in some of the units where formerly the sequence was in doubt or had been incorrectly inferred.

Growth and variation in a single species from a thin bed at one locality are examined statistically. The different dimensions are shown to be allometrically related both to each other and to the volume of the shell. It is argued that total width is the best measure of age of the individual and it is shown that at a certain width there is a break in the continuity of growth of the length and thickness.

This paper presents new LA-ICP-MS zircon U–Pb chronology, whole-rock geochemical and zircon Hf isotopic data for the felsic lavas of the Huili Group from the southwestern Yangtze Block. LA-ICP-MS zircon U–Pb dating shows that these rocks were emplaced in Late Mesoproterozoic time (∼1028 to 1019 Ma). Relative to typical I-type and S-type granitoids, all the samples are characterized by low Sr and Eu, and high high-field-strength element contents, high TFeO/MgO, enriched rare earth element compositions and negative Eu anomalies, indicating that they share the geochemical signatures of A-type granitoid. They can be further divided into two groups: Group I and Group II. Group I are A1-type felsic rocks and were produced by fractional crystallization of alkaline basaltic magmas. The Group II felsic lavas belong to the A2-type and were derived by partial melting of a crustal source with mixing of mantle-derived magmas. Both Group I and Group II felsic lavas may erupt in a continental back-arc setting. The coexistence of A1- and A2-type rocks in the southwestern Yangtze Block suggests that they can occur in the same tectonic setting.

The recently discovered massive and stockwork sulphide mineralization of Semblana-Rosa Magra and Monte Branco, situated ESE of the Neves–Corvo volcanogenic massive sulphide (VMS) deposit in the Iberian Pyrite Belt (IPB) is presented. Geological setting and tectonic model is discussed based on proxies such as palynostratigraphy and U–Pb zircon geochronology. The mineralization is found within the IPB Volcano-Sedimentary Complex (VSC) Lower sequence, which includes felsic volcanic rocks (rhyolites) with U–Pb ages in zircons of 359.6 ± 1.6 Ma, and black shales of the Neves Formation of late Strunian age. Massive sulphides are enveloped by these shales, implying that felsic volcanism, mineralization and shale sedimentation are essentially coeval. This circumstance is considered highly prospective, as it represents an important exploration vector to target VMS mineralization across the IPB, in areas where the Lower VSC sequence is present. The Upper VSC sequence, with siliciclastic and volcanogenic sedimentary rocks of middle–late Visean age, shows no massive mineralization but a late Tournaisian (350.9 ± 2.3 Ma) volcanism with disseminated sulphides was also identified. Nevertheless, stratigraphic palynological gaps were found within the Strunian and in the Tournaisian sediments, between the Lower and Upper VSC sequences, reflecting probable erosion and uplift mechanisms linked with extensional tectonics. The Semblana and Monte Branco deposits and the Rosa Magra stockwork are enclosed by tectonic sheets that dismembered the VSC sequence in a fold-and-thrust tectonic complex, characteristic of the NE Neves–Corvo region. The methodologies used allow a geological comparison between Neves–Corvo and other IPB mine regions such as Lousal–Caveira, Herrerias, Tharsis and Aznalcollar.

The Redwater Shale Member (Oxfordian) of the Sundance Formation was deposited in the foreland basin of the Cordillera during the last and largest marine transgression of the Jurassic in North America. One ichthyosaur (Ophthalmosaurus natans), two cryptocleidoid plesiosaurs (Tatenectes laramiensis, Pantosaurus striatus) and one pliosauromorph (Megalneusaurus rex) are known from the Redwater Shale Member. Ichthyosaurs are much more abundant than plesiosaurs, making up almost 60% of the fauna. No actinopterygian fish have been found, although four species have been identified from the lower Sundance Formation. At least one hybodont shark and one neoselachian are known from rare isolated teeth. The main food source for the marine reptiles was belemnoids, as indicated by preserved gut contents for all four species. In comparison, the better known and slightly older Peterborough Member of the Oxford Clay Formation of England, has a much higher taxonomic and ecological diversity, especially in the plesiosaurs, marine crocodiles, and fish. The lower diversity in the Redwater Shale Member probably reflects a much lower primary productivity in the Sundance Sea, as well as restricted migration from the open ocean to the north.

Osculocystis, a new scoliocystine cystoid, is characterized by reduced oral plates which form a tubercle; three pectinirhombs, B2: IL2, L2: R1, and L4: R4; and apparently only one brachiole. Osculocystis is based on a single specimen of the type species, O. monobrachiolata, from the Lower Silurian of Buildwas, Shropshire. It is the first recorded Lower Silurian cystoid from Britain and is most closely related to Glansicystis Paul.

Simple arithmetical techniques are set out whereby planimetric data, of the kind used in constructing area-height diagrams, can be made to yield additional quantitative information useful in description and comparison of relief. The most useful is an expression for mean available relief, which takes account of the form as well as of the height of interfluves. It is also shown how the depth of dissection of a datum surface can be mapped and measured.

Amongst the Carboniferous corals, not the least interesting are those species which, for one reason or another, may be difficult to classify, or at any rate diverge somewhat from the common order. It is with one of these aberrant members that the present communication is concerned; and it is, perhaps, not altogether unfitting that most of the material happens to be of Irish origin.

In the core of the Netherton Anticline at Saltwells, near Dudley, in the vicinity of a small area of basalt marked on the Geological Survey maps, Mr. King, in February last, discovered a series of rocks, ranging from the Upper Ludlow Mudstones to the Old Red Sandstone, cropping out from beneath the base of the Coal-measures of South Staffordshire. During April Mr. Lewis independently recognized Silurian here, and we agreed to work out the details together.

Structures similar to the monticules of Palaeozoic trepostomatous Bryozoa which occur in the Jurassic cyclostome Reptomultisparsa incrustans are described. They are interpreted as having a function analogous to that inferred for monticules. A smaller proportion of zooecia open on the monticules than between them, and, of these a higher proportion are occluded.These observations lend support to the theory proposed by Banta, McKinney & Zimmer (1974) that monticules functioned as regions of exhalant current chimneys on the zoarial surfaces of Bryozoa.

In this paper we present new petrological and whole-rock geochemical data for the Palaeoproterozoic metasedimentary rocks in the upper part of the Ji'an Group within the Jiao–Liao–Ji Belt, China, as well as zircon U–Pb age dates and in situ Lu–Hf isotope data. The new data improve our understanding of the original nature of the metasedimentary rocks, further providing insights into their tectonic setting and the evolutionary history of the northern segment of the Jiao–Liao–Ji Belt. The zircons can be divided into two groups, viz., one of magmatic origin and the other of metamorphic origin. Zircon U–Pb dating gave mean or statistical peak ages for the magmatic zircons at 2035, 2082, 2178, 2343–2421, 2451–2545, 2643–2814 and 2923–3446 Ma, and mean peak ages for the metamorphic zircons at 1855 and 1912 Ma, which indicate a maximum depositional age of 2.03 Ga and two-stage metamorphic events at c. 1.91 and 1.85 Ga for the metasedimentary rocks. Geochemical data show that (1) the protoliths of these rocks were mainly sandstones, greywackes and claystones, together with some shales; (2) the main sources of the sedimentary material were Palaeoproterozoic granites and acid volcanic rocks, with minor contributions from Archaean granitic rocks; and (3) the sediments were deposited in an active continental margin setting. Moreover, along the northeastern margin of the Eastern Block of the North China Craton there is evidence of ancient crustal materials as old as 3.76 Ga, and multiple crustal growth events at 3.23–3.05, 2.80–2.65, 2.54–2.45 and 2.28–2.08 Ga.