In 1991 a deep seismic line, MPNI-9101, was acquired in the southern North Sea. The line runs from the Mesozoic Broad Fourteens Basin in the north, across the West Netherlands Basin, onto the London–Brabant Massif in the south. The London–Brabant Massif is a WNW–ESE trending stable structure located beneath southeastern England, the southern North Sea and Belgium. The London–Brabant Massif represents the most easterly part of the Anglo-Brabant Massif. At the northern margin of the London-Brabant Massif, Devonian and Carboniferous siliciclastic and carbonate rocks onlap the massif. Farther south, shallow parts of the seismic line in the vicinity of the axial zone of the London–Brabant Massif are almost completely devoid of primary reflections. This zone is composed of strongly folded Lower Palaeozoic sedimentary units which have been mapped in the onshore part of Belgium. Numerous seismic reflection multiples from the base of the Cretaceous are observed on this part of the section. The southern limit of the zone is very abrupt and may correspond to a fault belt delimiting an area of magmatic rocks known in the onshore part of Belgium. Unusually the deeper parts of the seismic line show a strongly reflective lower crust beneath the London-Brabant, a phenomenon which has not been observed on other deep seismic sections across the massif. Two-way travel times to the base of the lower crustal reflective zone (corresponding to the Moho), increase from 10 seconds beneath the West Netherlands Basin in the north to 12 seconds beneath the London–Brabant Massif, suggesting a thickening of the crust.

Uranium enrichments (up to 4000 ppm) occur in the manganese and phosphorite assemblages of the Lower Cambrian clastic marine sedimentary sequence, Timna Basin, Israel. Two types of mineralization assemblages can be defined. Sedimentary stratabound assemblages consist of uranium-enriched stratiform manganese and phosphatic laminae, diagenetic (type A) manganese nodules composed of pyrolusite and hollandite laminae and phosphorite lenses. Fission-track maps show that the uranium is homogeneously distributed within host manganese and phosphatic minerals of these assemblages. Epigenetic assemblages are mainly composed of manganese- and phosphorite-bearing veins and secondary (type B) manganese nodules with a coronadite dominant mineralogy. Uranium is depleted in these assemblages, relative to the sedimentary stratabound assemblages.

The distribution of manganese and phosphorite assemblages has a marked bimodal character. Alternation between manganese and phosphatic laminae in the stratiform deposits reflects cycles of oxidizing and reducing conditions brought about by mixing and stratification of the waters in the Timna semi-closed depositional basins. Compaction of wet sediments led to remobilization and the formation of uranium-enriched manganese nodules at the aerated sediment–water interface, and uranium-enriched phosphorite lenses below the interface in reducing conditions. Epigenesis occurred through the passage of solution fronts which recrystallized the manganese and phosphatic minerals and remobilized metallic elements, particularly uranium which was leached away and is still being remobilized today.

The mechanism of uranium uptake in manganese phases is shown most probably to involve adsorbtion of [(UO2)3. (OH)5]+ complexes on precipitating minerals. Uranium is enriched in both the pyrolusite and hollandite laminae of type A nodules, but is particularly concentrated in the former (4000–10000 ppm). Thermodynamic calculations of the relative stabilities of pyrolusite and hollandite suggest that the pH conditions of hollandite formation were close enough to the pH limit of efficient uranium adsorption to inhibit its uptake relative to pyrolusite.

Palaeopascichnida is a problematic group of extinct organisms that is globally distributed in Ediacaran sequences of Avalonia, Baltica, Siberia, South China and Australia. The fossils related to Palaeopascichnida consist of serially or cluster-like arranged, millimetre- to centimetre-scale globular or allantoid chambers, which are characterized by substantial differences in preservation, leading to no consistent diagnosis for these organisms. Here we integrate morphometric variation, stratigraphic distribution and habitat settings of more than 1200 specimens from all known fossil localities. The results of the morphological analysis demonstrate variation in chamber shape and size, and allow us to recognize six valid species within the group. Statistical analysis of the specimen distribution with respect to sedimentary environments indicates a significant difference in palaeoecological settings between species, making a significant contribution to the evolution and systematic palaeontology of these problematic organisms and perspective on their use in Neoproterozoic biostratigraphy. Our revision and systematic study sheds new light on one of the least studied groups of the late Ediacaran biota.

The area to be described is that part of the Lias outcrop extending from Lincoln southwards to Barrow-on-Soar and Grantham, and includes south-west Lincolnshire and small portions of northeast Leicestershire and east Nottinghamshire (see Map, Fig. 1).

The rocks of this district were mapped by the Geological Survey, and an account of some of them was published in 1885 and 1888; the south-western part of the area has been resurveyed and described in more recent memoirs. A summary of the geology of the area was prepared in 1910 by A. J. Jukes-Browne, but except for these publications the literature is scattered and consists mainly of short papers; details of these are given where they are referred to.

Abundances of rare-earth elements (REE) and Th, Ta, Hf, Sc, Co, Ba determined by instrumental neutron activation analysis show similarity between lamprophyres and other potassic rocks including kimberlite. The Indian lamprophyres have fractionated REE patterns with enrichment of light REE. The light REEs show more variation than the heavy REEs within the group.

Lamprophyres occurring in intimate association with the alkaline basalt may be genetically related. The trace element characteristics of the abundant lamprophyre dykes in granitic terrain are unlikely to be generated by assimilation of alkaline basalt by granitic crust. Small amounts of partial melting in mantle pockets enriched in incompatible elements as a result of metasomatic processes would explain the elemental concentration observed in the lamprophyres.

The Weeks Formation preserves a diverse, yet largely undescribed, exceptionally preserved fauna of late Guzhangian age. Here I describe Notchia weugi gen. et sp. nov., a new arthropod characterized by a short cephalon, a trunk with 12 tergites and weakly differentiated into two morphological regions, and a spine-bearing rectangular telson. This combination of characters is incompatible with its assignment to any known groups. The new taxon also adds to examples of convergent evolution of ramified digestive glands in arthropods, possibly as an adaptation to infrequent feeding.

The area studied includes the majority of the main granite masses north of the belt of Ordovician and Silurian rocks running eastwards from Quimper to around Vitré and Laval. The heavy minerals of the Channel Islands granites have already been described by the writer (1). In the present paper the work is extended to the northern half of Finistère, and the greater part of the Côtes-du-Nord, Ille-et-Vilaine, and Manche. It is confined for the most part to the granites, and comparisons are made with those of the Channel Islands in an endeavour to obtain more definite evidence as to the age of the Jersey “Newer” Granites.

In the Hecla Hoek rocks of Prince Charles Foreland, field evidence indicates that chloritoid has developed only where conditions of extreme stress have affected pelitic rocks of a certain type. Microscopic examination confirms that many of the chloritoid-bearing rocks are extremely strained, and demonstrates that growth of the mineral was contemporaneous with movement. The distribution of chloritoid is in complete discordance with the pattern of regional metamorphism.

Bedding-parallel fibrous calcite veins in black shales (Cretaceous, southern UK) were investigated using a combined field, stable isotopic geochemistry, petrographic and crystallographic method to examine their formation mechanism. Calcite veins occur in all shale beds and are most abundant in the bituminous shales of the Chief Beef Beds. The calcite fibres in these veins exhibit either an antitaxial fibre growth with curvy stylolites as the median zone, or a predominantly syntaxial, upwards growth. The calcite veins range from –0.49 to 1.78‰ of δ13C values, and –6.53 to –0.03‰ of δ18O values, which are both similar to those of their host shales. Our petrographic observations demonstrate that subhorizontal and interconnecting microstylolite networks commonly occur within the calcite veins. Equant calcite grains in the median zones exhibit indenting, truncating and also interpenetrating grain contacts. It is interpreted that the fibrous calcite veins were sourced by neomorphic calcite from their host shales, with evidence from the δ13C signatures, pressure-solution features (stylolites, microstylolites and grain contact styles) and embedded fossil ghosts within the veins. The diagenetic fluids, from which calcite was precipitated, were a mixing of the original seawaters and 18O-depleted meteoric waters. Development of bedding-parallel calcite veins is considered to have been enhanced by pressure solution as a positive feedback mechanism, which was facilitated by the overburden pressure as the maximum principal stress. Calcite fibres, with a predominant subvertical c-axis orientation, exhibit a displacive growth in porous shales and a replacive growth at vein-limestone contacts. This study highlights the critical role of pressure solution in the formation of bedding-parallel calcite veins during burial and diagenesis of immature black shales.

The epizoan Vermiforichnus Cameron (1969b) from the Upper Ordovician (Caradoc) of the Berwyn Hills and the Welsh Borders is host-specific, occurring in association with the strophomenid Macrocoelia and the orthid Heterorthis. The spionid polychaete probably responsible for the production of the Vermiforichnus borings inhabited both live and dead individuals. In live individuals Vermiforichnus was located at the anterior margin and oriented perpendicular to the commissure, this position affording both a means of protection and a more efficient feeding position. In dead individuals population density was lower and the borings were randomly oriented. Vermiforichnus was restricted to inner—outer sublittoral environments and, as such, is a useful palaeoenvironmental guide.

The Diguva Sonaba area (Vishakhapatnam district, Andhra Pradesh, South India) represents part of the granulite-facies terrain of the Eastern Ghats Mobile Belt. The Precambrian metamorphic rocks of the area predominantly consist of mafic granulite (±garnet), khondalite, leptynite (±garnet, biotite), charnockite, enderbite, calc-granulite, migmatic gneisses and sapphirine–spinel-bearing granulite. The latter rock type occurs as lenticular bodies in khondalite, leptynite and calc-granulite. Textural relations, such as corroded inclusions of biotite within garnet and orthopyroxene, resorbed hornblende within pyroxenes, and coarse-grained laths of sillimanite, presumably pseudomorphs after kyanite, provide evidence of either an earlier episode of upper-amphibolite-facies metamorphism or they represent relics of the prograde path that led to granulite-facies metamorphism. In the sapphirine–spinel-bearing granulite, osumilite was stable in addition to sapphirine, spinel and quartz during the thermal peak of granulite-facies metamorphism but the assemblage was later replaced by Crd–Opx–Qtz–Kfs-symplectite and a variety of reaction coronas during retrograde overprint. Variable amounts of biotite or biotite+quartz symplectite replaced orthopyroxene, cordierite and Opx–Crd–Kfs–Qtz-symplectite at an even later retrograde stage. Peak metamorphic conditions of c. 1000°C and c. 12 kbar were computed by isopleths of XMg in garnet and XAl in orthopyroxene. The sequence of reactions as deduced from the corona and symplectite assemblages, together with petrogenetic grid and pseudosection modelling, records a clockwise P–T evolution. The P–T path is characteristically T-convex suggesting an isothermal decompression path and reflects rapid uplift followed by cooling of a tectonically thickened crust.

Eight inliers of Carboniferous Limestone are situated between Ashby de la Zouch and Melbourne on the northeastern side of the Leicestershire Coalfield. They may conveniently be divided into a western group consisting of the Ticknall, Calke, and Dimminsdale exposures, all of which occupy comparatively low ground in valleys, and an easterly group, Breedon Hill, Breedon Cloud, Barrow Hill, Osgathorpe, and Grace Dieu. The first three of the latter group form prominent hills rising above the Triassic rocks which surround them. They are also remarkable for the high dips in the rocks composing them. In the other inliers dips of less than 15° are the rule, while dips of about 5° are common.

A specimen of the trepostome bryozoan Orbipora from the Lower Arenig of south Wales is described and figured. This is currently the oldest unequivocal bryozoan recorded in the literature. Although mostly decalcified, the colony preserves clear remnants of the large styles which characteristically indent the zooecial apertures in Orbipora. The wide palaeogeographical distribution of Orbipora in the early Ordovician is consistent with the hypothesized planktotrophic larval phase. Theoretical considerations and evidence from the occurrence of Orbipora in south Wales suggest that nearshore clastic environments would be fruitful settings in which to search for further early bryozoans, although quality of preservation may be poorer than in offshore carbonates.

A swarm of basaltic and camptonitic dykes in the Northern Highlands of Scotland has been studied. The dykes include monchiquite, olivine basalt, olivine dolerite, and camptonite, and a study of the relations of the various types in individual dykes suggests that the camptonites have arisen by the crystallization of late fractions from a magma of fairly normal dolerite type.

Results of detailed remapping of the Kirkcudbright area in the Southern Belt of the Southern Uplands of Scotland, together with new palaeontological data, necessitate revision of the regional structure, and re-interpretation of the sedimentary history of the northwest margin of the Lower Palaeozoic lapetus Ocean. On the east side of Kirkcudbright Bay, at least six sediment-ologically and structurally distinct, subvertical tectonic blocks can be distinguished. Recognition of the Raeberry Castle Formation as a Wenlock turbidite sequence, rather than mid- to late Llandovery as previously interpreted, removes the need to postulate the existence of an axial rise and a distinct basin adjacent to the south, in mid- to late Llandovery times.

Along the Dinaric–Hellenic orogen, the Late Jurassic – Early Cretaceous ophiolite obduction over the Adria continental margin was sealed by sedimentation of clastic terrestrial deposits rapidly followed by a widespread carbonate platform system since the Early Cretaceous period. These Cretaceous sediments presently crop out over areas of varying extension, from several hundred kilometre wide undeformed continuous covers to small-scale tectonic slivers involved in the tectonic stack following the latest Cretaceous–Palaeogene collision. These deposits are unconformably sedimented above the units formed by the Late Jurassic to Early Cretaceous nappe stacking above the eastern Adria continental margin. We studied these deposits in a large area between western Serbia and eastern Bosnia. In the studied area, these deposits are divided into three lithostratigraphic groups according to their age, depositional environment and type of underlying basement. The Mokra Gora Group sediments (upper Aptian–Maastrichtian) were deposited on top of previously obducted and weathered ophiolites, the Kosjerić Group (Cenomanian–Campanian) overlies composite tectonic units comprising obducted ophiolites and their underlying continental basement portions, while the Guča Group (Campanian–Maastrichtian) exclusively rests on top of continental basement. The reconstructed sedimentary evolution of these groups, together with the comparison with the syn- and post-obduction deposits at the front of the ophiolitic nappe(s) in a wider area of the internal Dinarides (e.g. Pogari Group and Bosnian flysch), allowed us to clarify the obduction mechanisms, including their tectonic context, the changes in depositional environments and the timing of depositional and tectonic events, and, in a wider view, shed light on the geodynamic evolution of the Dinaric belt.

The extent to which a country suffers denudation at the present time is to be measured by the amount of mineral matter removed from its surface and carried into the sea. An attentive examination of this subject is calculated to throw some light on the vexed question of the origin of valleys and also on the value of geological time. Of the mineral substances received by the sea from the land, one portion, and by far the larger, is brought down by streams, the other is washed of by the waves of the sea itself.

Several of the tubes of this singular genus are exposed in section on the weathered (water-worn ?) surface of a piece of limestone. The tubes are of an elongate conical form, rather rapidly tapering, and straight or slightly curved, the longest about 10 lines; each contains several smaller tubes one within the other, the last of these little hollow cones being the chamber of habitation. The shell is thick, and has consequently not been crushed, two or three of the inner tubes retaining their cylindrical form, as seen in the section Fig. 1b.

The real nature of marine reptile fossils found in England between the 1700s and the beginning of the 1900s remained enigmatic until Mary Anning's incredible fossil discoveries and their subsequent study by eminent English and French scientists. In 1820, Georges Cuvier acquired several ichthyosaur specimens found by Mary Anning, now kept or displayed in the Palaeontology Gallery of the Muséum National d'Histoire Naturelle (MNHN) in Paris. Four years later, Cuvier obtained a plesiosaur specimen from Mary Anning, only the second ever discovered. Cuvier was fascinated by these fossils and their study allowed him to apply his comparative anatomical method and to support his catastrophist theory. We have re-examined these important specimens from a historical point of view, and describe them here taxonomically for the first time since Cuvier's works. The Paris specimens belong to two different ichthyosaur genera (Ichthyosaurus and Leptonectes) and one plesiosaur genus (Plesiosaurus).