Latest Devonian A-type granite-gabbro plutons, in part ductilely deformed, are spatially associated with the strike-slip Cobequid fault zone. The youngest intrusions are close to the Cobequid fault zone, which was the main conduit for magma. Two phases of deformation accompanying magma emplacement are recognized. Early magmas intruded ductile rocks during left-lateral oblique thrust movements. A second stage of right-lateral oblique slip normal faulting accommodated uplift of the plutons when coarse granite was emplaced in the crestal regions. Cross-cutting late stage porphyries, granitic clasts in marginal basins cut by granitic dykes, and superposition of brittle on ductile structures all indicate rapid uplift of the plutons. The geometry of the Cobequid fault zone shows that pluton emplacement was not the result of extension in releasing bends during transcurrent shear. Rather, flower-structure high-angle faults acted as magma conduits and space was created by two processes: translation of wall rocks along thrust faults at depth, developing space away from the master fault zone and backward collapse of the uplifted magma chamber creating space towards the fault zone.

Pb–Pb single zircon ages of 546.2 ± 1.2 Ma demonstrate that the augen gneisses in the southern Menderes Massif were generated from Pan-African intrusions. During the Alpine orogenic evolution of the Menderes Massif these granites were metamorphosed and transformed into augen gneiss in an extensional top-to-the-south shear zone, located between augen gneisses and overlying schists. Quartz fabrics suggest a pronounced static recrystallization that post-dates the ductile deformation in the shear zone. Ar–Ar muscovite ages of 43–37 Ma from augen gneisses and schists suggest that ductile deformation and subsequent cooling occurred in the Eocene. These results contradict previous models that (1) interpret the extensional shear zone as late Oligocene in age and (2) regard the augen gneisses as syntectonic with respect to ductile extensional deformation.

By the new method of Sm—Nd isotopic dating on phosphatic small skeletal fossils and collo-phanite minerals, the Zhongyicun Member of the earliest Cambrian Meishucun Stage at Meishucun in Yunnan, southern China, has been dated at 562.8 ± 7.9 Ma and 562.1 ± 5.7 Ma. Another Sm—Nd age, 570.3 ± 17.1 Ma, has been obtained with samples from the Zhongyicun Member in Yunnan and its stratigraphic equivalents in Sichuan and Xinjiang. These data tend to suggest that the best age estimate of the Precambrian—Cambrian boundary is very likely within the range of 560–570 Ma. As biophosphates and sedimentary phosphates are widely distributed in sequences of the Precambrian—Cambrian transition, the Sm-Nd isotopic method is recommended as an effective approach for precise dating of the initial Cambrian boundary.

A small suite of trace fossils from the Zavkhan Basin (Govi-Altay) includes many of the ichnotaxa typical of the Nemakit-Daldynian, Tommotian and younger Cambrian stages, and other indeterminate forms. The traces are almost entirely from the sandstone intervals of the large-scale alternations of carbonate and siliciclastic sediments, thus emphasizing the facies and taphonomic controls on trace fossil distribution, and hence the inherent difficulties in using trace fossils in detailed global correlation, especially in using first appearances. The assemblage of traces and biofabrics is seen as resulting from the partly non-uniformitarian (non-actualistic) sedimentary environments that pertained over the boundary interval, rather than as evolutionary failures and subsequently vacated environments.

Neoproterozoic–Cambrian rocks of the Zavkhan Basin (Govi-Altay, western Mongolia) comprise large-scale alternations of siliciclastic- and carbonate-dominated units (cf. ‘Grand Cycles’). Analysis of such depositional sequences near the base of the Cambrian confirms that the distribution of trace fossils, small shelly fossils and calcimicrobial structures was strongly controlled by ecology and taphonomy, corresponding to specific points in a sea-level cycle. Evolution of the Cambrian biota is thus viewed through aseries of narrow time windows, once only for each depositional cycle. Correlation of the Precambrian–Cambrian boundary level on the basis of the first appearance of the Phycodes pedum assemblage is also fraught with difficulty, since stratigraphic resolution may be limited to a single sea-level cycle(c. 1–5 Ma). It is suggested that, in many cases, basin analysis will need to be undertaken before this boundary can be drawn.

There has been a long-standing controversy concerning the form of the Beinn an Dubhaich Granite, which intrudes Cambro-Ordovician limestones and contains enclosures of limestone at outcrop. We have undertaken a three-part geophysical investigation with the aim of resolving some issues raised by previous workers. Our most significant finding results from the measurement of a gravity profile across Beinn an Dubhaich. It reveals a negative anomaly of more than 2 mGal over the granite outcrop. Our preferred model to fit this anomaly is a steep-sided granite stock extending down to about 1 km depth, which implies that the limestone enclosures are roof pendants. In a supplementary study, we measured magnetic profiles across dykes in some of the limestone enclosures in order to determine the depth to the contact with the underlying granite. However, in the most clear-cut cases we could only determine a minimum depth of 20 m, and were unable to constrain the maximum depth. In hindsight, we suggest that microgravity surveying would be a better method for determining the thicknesses of the limestone roof pendants. In the third part of the investigation, we measured a tight grid of magnetic profiles to the northeast of the granite outcrop to test a previous suggestion that dyke-like lobes of granite intrude pre-existing fractures in the overlying limestones. We located several large magnetic anomalies associated with outcropping doleritic dykes and concluded that these had not been correctly identified in the earlier work. Consequently, the ground magnetic profiles acquired to date provide no valid evidence to support the idea of an interfingering contact between the limestones and the underlying granite.

The specimen is identified as the partial cranium of a nodosaurid ankylosaur (Ornithischia: Thyreophora) on the basis of the presence of bone which is fused to the dorsal surface of the skull and has secondarily closed the upper temporal fenestrae. The only unequivocally nodosaurid material recovered from the Isle of Wight to date comes from Wealden facies, and has been referred to the genus Polacanthus; it is considered highly probable that this new skull is referable to the same genus. Despite having undergone abrasion, through post-emergence water-rolling, the skull and cranial walls have proved to be relatively informative of the general anatomy of the braincase and the neural and vascular anatomy of this part of the head. The anatomy of the braincase of most ankylosaurs (with the notable exception of the juvenile specimens of the ankylosaurid Pinacosaurus) is surprisingly poorly known, despite the relative abundance of cranial material in North American and Asian collections.

The cranial neural and vascular anatomy is well shown in this specimen and enables the first detailed description of nodosaurid endocranial structures. The general form of the brain can be outlined from the structure of the endocast and the principal lobes can be identified; the majority of the cranial nerves have been identified, and a significant component of the associated vascular system is also visible. In most respects the endocast shows a neural anatomy which is common to that known in most dinosaurs. When compared to their nearest relatives, the ankylosaurid ankylosaurs (Euoplocephalus), the nodosaurid endocranial cast shows a more pronounced cerebral flexure, a forebrain which is broader and more expanded dorsally, and a more prominent cerebellum (although there is no evidence for a floccular lobe); there are minor differences in the arrangement of the cranial nerves, and the dorsal portions of the vascular system are better shown.

Because of erosion, the olfactory lobes of this specimen of cf. Polacanthus are not preserved, and cannot be compared to those of ankylosaurid ankylosaurs; the latter are unusual in the strong separation of the lobes (reflected in the divergent olfactory stalks); this feature may be associated with the very complex passages within the nasal region of the skull, which are lacking in the nodosaurids described to date.

New geological mapping has revealed further details of the tectonic and stratigraphic effects of Devonian and later reactivations of the Billefjorden Fault Zone, one of a number of important north—south trending lineaments in Svalbard. Analysis of offsets along the many steeply-dipping faults within the zone, and effects on the subsidence and deformation of the adjacent crustal blocks, is presented as a series of tectonic maps from the Late Devonian through to the Tertiary. Late Devonian sinistral transpression, suggested previously, cannot be ruled out, and Carboniferous reactivation was dominated by extension, with possibly a slight dextral strike-slip component. After Late Carboniferous to Early Cretaceous platform subsidence, during which the fault zone had little effect on sedimentation, development of the Tertiary West Spitsbergen Fold Belt (related to the opening of the Arctic Ocean) involved compressive (and transpressive?) reactivation of basement-seated structures further east, including the Billefjorden Fault Zone. In the Billefjorden—Austfjorden area this produced a large monoclinal fold across the fault zone, which was later cross-cut by extensional structures to produce the present day Billefjorden syncline. This localized late extension is related to a slight variation in the trend of the Billefjorden Fault Zone through this area.

The first specimen of the ankylosaur genus Polacanthus from the mainland Barremian of southeast England is described as Polacanthus rudgwickensis sp.nov. Polacanthus rudgwickensis is larger than Polacanthus foxii, and there are significant differences in the dermal armour, the tibia and caudal vertebrae of the two species. Polacanthus foxii appears to be restricted at present to the Isle of Wight with one specimen from southwest England, whilst Polacanthus rudgwickensis is only known from Sussex. This geographical distribution, the palaeobiological implications and possible sexual dimorphism are discussed for this genus.

The transition zone between 100 % dykes and high-level plutonic rocks of the Solund-Stavfjord Ophiolite Complex is complex due to the existence of many lithologies with different and variable contact relationships. The rocks of the plutonic complex vary in composition from FeTi basaltic to quartz dioritic, and the grain sizes vary from fine to pegmatitic. Felsic varieties are produced by fractional crystallization of basaltic magma as demonstrated by geochemical evolution and by gradual transition from gabbro to quartz diorite. Patches of fractionated dioritic rocks may show both gradual and intrusive relationships with the surrounding host gabbro. This demonstrates that late-stage liquids commonly left the source region and locally intruded the surrounding parent rocks. The high-level plutonic rocks are thoroughly epidotized and are cut by dykes consisting of granoblastic epidote and quartz. The high-level plutonic complex is associated with irregular bodies of fine- to medium-grained plagioclase-porphyritic diabase of high MgO content. These diabase bodies are intruded by dykes that become progressively more regular in shape. The plutonic complex locally shows intrusive relationships with the overlying 100% dyke complex, but is itself cut by two dyke swarms. The dykes of the first swarm formed while the plutonic complex experienced sinistral shear strain, and the dykes are generally less regular and thinner than the dykes of the second swarm. This indicates that the dykes of the first swarm intruded while the rocks of the plutonic complex were still hot, while the next dyke swarm intruded later when the rock complex was colder. Dykes of both swarms range in composition from slightly to strongly fractionated, suggesting that the magma chambers they were expelled from underwent significant fractionation in between magma replenishment. Numerous dykes of both swarms carry large quantities of glomeroporphyritic aggregates of plagioclase and altered clinopyroxene, indicating that the source area to the dykes very often was a crystal mush.

Seven radiocarbon dates of carbonate shells and charcoal from the upper two metres of sediment in the Indo-Gangetic plains of northern Bihar, eastern India, can be divided into three groups, with the following approximate ages: 2400±45 a BP (two samples), 1100±45 a BP (four samples) and 765±45 a BP (one sample). This evidence for at least three episodes of sedimentation in the last 2400 a contrasts with evidence of greater ages from similarly near-surface sediments in the middle Gangetic plains of Uttar Pradesh, further west. In these more westerly areas, greater ages and well-developed river terraces point to much more restricted late Holocene sedimentation. Rates of net sediment accumulation calculated using our Bihar ages, spanning a period of the order of 103–104 a, are similar to those calculated for periods of the order of 105–106 a for the Himalayan foreland basin. This suggests that, in the whole basin case, short-period rates higher than the Bihar rates have been compensated by longer than Bihar periods of non-deposition or erosion.

The first specimen of the ankylosaur genus Polacanthus from the mainland Barremian of southeast England is described as Polacanthus rudgwickensis sp.nov. Polacanthus rudgwickensis is larger than Polacanthus foxii, and there are significant differences in the dermal armour, the tibia and caudal vertebrae of the two species. Polacanthus foxii appears to be restricted at present to the Isle of Wight with one specimen from southwest England, whilst Polacanthus rudgwickensis is only known from Sussex. This geographical distribution, the palaeobiological implications and possible sexual dimorphism are discussed for this genus.

We report U—Pb and 207Pb/206Pb zircon ages for a granulite facies gneiss assemblage exposed in a large quarry at Ihosy, southern Madagascar. The granulites are derived from pelitic to arkosic sediments and attained equilibrium conditions at 650–700°C and 4–5 kbar. Higher P—T conditions of 750–800°C and 6 kbar in the presence of low water activities have led to dehydration melting processes. The formation of granitic melts, which (partly) moved away from their source region, intruded into upper parts of the metapelitic gneisses as small granitic veins and left behind granulitic garnet-cordierite-quartz bearing rocks. Detrital zircons in a sample of metapelite and a sample of quartzofeldspathic gneiss yielded ages between ˜720 and ˜1855 Ma, suggesting a chronologically heterogeneous source region and a depositional age of less than ˜720 Ma for these rocks. High-grade metamorphism and anatexis are documented by zircon ages between 526 ±34 and 557 ±2 Ma with a mean age of about 550 Ma. The broad lithologies, metamorphic grades and ages recorded in the Ihosy rocks are similar to those in the Wanni Complex of northwestern Sri Lanka and in high-grade assemblages of southernmost India and support the contention that all these terrains were part of the Mozambique belt which formed as a result of collision of East and West Gondwana in latest Precambrian time.

The Neoproterozoic–Cambrian succession in the Zavkhan Basin of western Mongolia preserves early Cambrian bioconstructions of Nemakit-Daldynian to Botomian age. As elsewhere (Siberia, Morocco), the Nemakit-Daldynian bioconstructions in the upper Tsagaan Oloom Formation to lower Bayan Gol Formation interval were purely calcimicrobial. Spectacular calcimicrobial ‘patch reefs’ of presumed Tommotian age are present in the lower Bayan Gol Formation. In contrast, late Atdabanian–early Botomian bioconstructions are varied and well developed in the upper Salaany Gol Formation including, in addition to calcimicrobial bioherms, Gordonophyton–Razumovskia crusts, radiocyathan—archaeocyathan bioherms and thickets of the ramose archaeocyath Cambrocyathellus.

These latter Zavkhan Basin buildups show some ecological and sedimentological features in common with coeval bioconstructions in South Australia, which also developed under a tectonically active regime.

The Channel Islands of Guernsey and Sark are amongst the few localities within the Neoproterozoic, Cadomian orogenic belt where Palaeoproterozoic basement is exposed. Basement units collectively referred to as ‘Icartian’ comprise orthogneisses (e.g. the c. 2000 Ma Icart granite gneiss), metasediments and amphibolites. On Guernsey, the protolith to the Icart granite gneiss was intruded into metasediments already deformed during a D1 deformation event. Both were variably deformed during a D2 event within an approximately north—south trending, steeply dipping, oblique dextral shear zone. On Sark, metasediments and amphibolites carry a D1 fabric (not necessarily correlatable with that on Guernsey) which was deformed during D2 to form recumbent—gently inclined folds and tectonic fabrics which locally carry top-to-the-south kinematic indicators. Early Cadomian quartz diorites which intruded the Icartian basement carry variably developed magmatic and moderate temperature (400–550 °C) LS solid-state fabrics which are similarly oriented to D2 basement structures. This indicates that the quartz diorites were emplaced and deformed during a protracted D2 event. Published 40Ar/39Ar amphibole cooling ages of c. 600 Ma from Guernsey and Sark quartz diorites and a host Icartian amphibolite are consistent with reworking of basement units during the Cadomian Orogeny. The contrasting kinematic pattern during Cadomian deformation implies that a flat-lying shear zone on Sark may have accommodated oblique dextral strike-slip movement on Guernsey with an overall southerly direction of tectonic transport. Deformation most likely occurred in the hanging-wall of a major south-dipping Neoproterozoic subduction zone.

The Permo-Triassic Trinity Peninsula Group is a widespread, regionally metamorphosed metasedimentary sequence in northern Graham Land, Antarctica, which forms the local ‘basement’ to the mainly Jurassic–Cretaceous Antarctic Peninsula magmatic arc. The metamorphic grade, thermal evolution and pressure series of this major tectono-stratigraphical unit are largely unknown. Determining the nature of the metamorphism has relied hitherto on conventional optical identifications of the major phases, mainly in rare volcanic beds. However, diagnostic mineral parageneses are generally absent and the precise metamorphic grade is unknown or has to be inferred over large areas. Using white mica (illite) crystallinity of interbedded mudrocks, the Trinity Peninsula Group is now shown to have been pervasively altered mainly at anchizonal and epizonal grades. Conditions ranged from upper anchizonal in the northeast to thoroughly epizonal in the southwest. Outwith thermal aureoles near plutonic intrusions, the alteration temperatures ranged mainly from 250 to 325 °C, exceeding 300 °C in the highest-grade (epizone/greenschist facies) parts of the sequence. The facies series, K-white mica b cell dimension measurements and mineral phases present are characteristic of an intermediate pressure series altered under moderate geothermal gradients (<35 °C/km), corresponding to burial depths of c. 7–10 km. Unroofing and substantial erosion of the Trinity Peninsula Group took place during polyphasal vertical tectonic movements linked to the development of the magmatic arc in northern Graham Land. The geological setting of the Trinity Peninsula Group is ambiguous and could have been a foreland (or back-arc) basin or the mid- to upper levels of an accretionary prism.

Five overlapping sections from the thick Neoproterozoic to early Cambrian sediments of western Mongolia were analysed to yield a remarkable carbon-isotope, strontium-isotope and small shellyfossil (SSF) record. Chemostratigraphy suggests that barren limestones of sequences 3 and 4, which lie above the two Maikhan Uul diamictites, are post-Sturtian but pre-Varangerian in age. Limestones and dolomites of sequence 5, with Boxonia grumulosa, have geochemical signatures consistent with a post-Varangerian (Ediacarian) age. A major negative δ13C anomaly (feature ‘W’) in sequence 6 lies a shortdistance above an Anabarites trisulcatus Zone SSF asemblage with hexactinellid sponges, of probable late Ediacarian age. Anomaly ‘W’ provides an anchor point for cross-correlation charts of carbon isotopes and small shelly fossils. Trace fossil assemblages with a distinctly Cambrian character first appear in sequence 8(Purella Zone), at the level of carbon isotopic feature ‘B’, provisionally correlated with the upper part of cycle Z in Siberia. A paradox is found from sequence 10 to 12 in Mongolia: Tommotian-type SSFs continue to appear, accompanied by Nemakit-Daldynian/Tommotian-type 87Sr/86Sr ratios but by increasingly heavyδ13C values that cannot be matched in the Tommotian of eastern Siberia. The steady rate of generic diversification in Mongolia also contrasts markedly with the Tommotian ‘diversity explosion’ in eastern Siberia, which occurs just above a major karstic emergence surface. One explanation is that sequences 10 to 12 in Mongolia preserve a pre-Tommotian portion of the fossil record that was missing or removed in easternSiberia. The Mongolian sections certainly deserve an important place in tracing the true course and timing of the ‘Cambrian radiation’.

Deep-marine strata of the Skiddaw Group, deposited in high southerly palaeolatitudes on the northern margin of Eastern Avalonia in the early Ordovician, contain a diverse ichnofauna dominated by examples of fodinichnia. This includes Alcyonidiopsis pharmaceus, several ichnospecies of Chondrites, Dictyodora zimmermani, Glockerichnus radiatus, Gordia marina, Ixalichnus enodius, two or possibly three ichnospecies of Phycodes, Planolites montanus, Volkichnium volki, an ‘arthropod-produced? repichnion’, ‘paired pits’, ?Gordia aff. marina, ‘thinly-walled, looping, burrows’ and burrows of Planolites/Palaeophycus affinity. Stellascolites radiatus Etheridge, 1876 is reassigned to the ichnogenus Glockerichnus Pickerill, 1982 as Glockerichnus radiatus (Etheridge, 1876).

Several of the ichnotaxa are present in other ichnofaunal assemblages of early Ordovician age which were also emplaced at high southerly palaeolatitudes. The relatively high diversity of this ichnofaunal assemblage supports suggestions that models of the rate at which the deep-marine environment was colonized during the early Phanerozoic are in need of revision.

A significant 5- to 30-metre-thick interval of siliciclastic turbidites forming the First Flysch is present in the deep-water succession of the Pindos Zone. Nannofossil investigations in the central parts of the Pindos Mountains of mainland Greece indicate an assemblage of the Marthasterites furcatus zone (CC13). The presence of M. furcatus, together with common Quadrum gartneri suggests that the turbidites were deposited mainly during the middle to upper part of the late Turonian. The siliciclastic turbidites are interpreted as deposits of a lowstand fan as a result of a pronounced short-time eustatic sea-level drop in the late Turonian.

A macroscopic fold formed during the fourth deformation, D4, in the Robertson River Metamorphics, north Queensland, Australia. Growth of biotite, garnet, staurolite and andalusite porphyroblasts also occurred synchronous with D4. Only biotite porphyroblasts have formed preferred alignments across the fold, and they define two dominant orientations. The more common is parallel to D4 fold axes, which is also parallel to D1 D2 and D4 intersection lineations. The other varies up to 90° from this within the D4 axial plane. Mineral elongation lineations do not reflect the extension direction of the deformation in which they formed (D4), but are a function of pre-existing anisotropics in the rock parallel to intersection lin-eations. Porphyroblast growth is inferred to be a result of microfracturing along favourably oriented linear anisotropics formed by multiple intersection of foliations, as well as parting of the the S1, and S2 foliations.