The Lake Ambrose volcanic belt (LAVB) outcrops as a 45 km long northeast-trending belt of mafic and felsic volcanic rocks along the eastern side of the Victoria Lake Group in south-central Newfoundland. It comprises roughly equal proportions of mafic pillow basalt and high silica rhyolite, locally interbedded with epiclastic turbidites. Volcanic rocks have been metamorphosed in the greenschist facies and are extensively carbonatized.

U-Pb (zircon) dates from rhyolite at two, widely separated localities give identical ages of 513 ± 2 Ma (Upper Cambrian), and this is interpreted as the eruptive age of the volcanic sequence. Primitive arc and low-K tholeiites can be recognized on the basis of major and trace element geochemistry, ranging from LREE-depleted to LREE-enriched. Geochemical variation between mafic volcanic types is interpreted predominantly to reflect contrasts in source characteristics and degree of partial melting; some variation within each geochemical type attributable to fractional crystallization can be recognized. Detailed examination of some samples indicates that the heavy REE and related elements have locally been mobile, probably as a result of carbonate complexing.

The LAVB is the oldest well-dated island arc sequence in Newfoundland, and perhaps in the Appalachian–Caledonian Orogen. Its age requires modification of widely held models for the tectonic history of central Newfoundland. It is older than the oldest known ophiolite, demonstrating that arc volcanism was extant before the generation of the oldest known oceanic crust in this part of Iapetus. It further demonstrates that there was a maximum of approximately 30 Ma between the rift-drift transition which initiated Iapetus, and the initiation of subduction. This suggests that the oceanic sequences preserved in Newfoundland represent a series of arcs and back arc basins marginal to the main Iapetus Ocean, and brings into question whether the Appalachian accreted terranes contain any remnants of normal mid-ocean ridge type Iapetan crust.

Cathodoluminescence (CL) examination of Recent biogenic carbonates shows that they are often luminescent regardless of their mineralogical composition (calcite v. aragonite), habitat (marine v. fresh water), way of life (sessile v. vagile) or environment (hyper- v. hyposaline water). Thus, the presence of luminescence in biogenic particles is not a reliable indicator of diagenetic alteration as some authors have suggested. In addition, CL can reveal variations in the mineralogy of shell material (e.g. regenerated calcitic v. primary aragonitic) and can highlight growth-related structures. Manganese (Mn2+) is the most likely activator of this luminescence, and its content in the shells of benthic organisms seems to be linked to growth rate, ontogeny, open sea conditions, bathymetry and salinity. In neritic environments the Mn2+ content and the CL of molluscs and foraminifera appear to increase with decreasing salinity. This study indicates that CL may be an important tool for the determination of environmental and ontogenetic parameters in biogenic carbonates in addition to its current use indiagenetic studies.

In northern Euboea, central eastern Greece, an up to 3 km-thick polygenetic melange (Pagondas complex) is structurally interleaved between a Triassic–Jurassic carbonate platform (Pelagonian Zone) and an overriding harzburgitic ophiolite. The melange mainly comprises late Triassic shallow-water limestone and calciturbidites, radiolarites, Triassic–Jurassic tholeiites, alkaline basalts and minor andesites. The units concerned range from kilometre-sized thrust sheets, and detached blocks, to broken formation and structureless, or bedded matrix-supported conglomerates (diamictite). The melange includes remnants of Neotethyan oceanic lithosphere, overlain by radiolarites, hemipelagic carbonates and distal calciturbidites derived from a Mesozoic carbonate platform. Tholeiites were erupted at a Triassic–Jurassic spreading axis, whilst within-plate-type alkali basalts are interpreted mainly as seamounts. Kilometre-scale detached blocks of shallow-water coralline limestone are identified as collapsed atolls, formed within an ocean and/or along the rifted continental margin. Volcaniclastic sediments are locally interbedded with radiolarite, and reflect post-volcanic erosion of the ocean floor. Intra-oceanic convergence began, apparently in late early Jurassic time, giving rise to the Euboea ophiolite above an inferred westwards-dipping subduction zone. The Pagondas Complex then developed as an accretionary prism. The subduction trench later collided with the Pelagonian passive margin, driving the hot Euobea ophiolite over the accretionary complex, to produce amphibolites and greenschists of the metamorphic sole. Trench–margin collision then drove the entire supra-subduction zone complex, apparently eastwards, downflexing the Pelagonian carbonate platform to form a foredeep in which late Jurassic (Kimmeridgian–Tithonian) radiolarian sediments accumulated. During emplacement, the accretionary complex was disrupted and partly resedimented as debris flows, turbiditic volcaniclastic sandstone and shale in a foredeep, or foreland basin setting.

Laser ablation techniques permit the determination of the stable isotopic ratios of finely crystalline calcite cements in chalks for the first time. Modelling of fluid–rock interaction using whole rock and laser ablation stable isotopic data indicates that carbonate mineral diagenesis in the Eldfisk Field consisted largely of the dissolution and reprecipitation of calcite with little associated loss of porosity. Cementation by calcite derived from stylolites apparently occurred throughout the Eldfisk Field chalk, but had only a subsidiary effect on whole rock isotopic ratios. Oxygen isotopic data indicates a pore water temperature of 50–80 °C during the bulk of chalk recrystallization. Increases in whole rock δ13C values with depth are likely the result of bacterial methanogenesis during chalk recrystallization.

Detailed sampling of the Little Minch Sill Complex reveals that it is composed of both single and multiple sills. These are formed of three main, genetically related units: picrite, picrodolerite and crinanite, which are the result of differentiation of an alkali-olivine basalt magma (approximately 10% MgO) in an upper-crustal magma chamber. Variations in igneous stratigraphy and the presence of internal chills in the Trotternish sills suggest that they were emplaced by multiple intrusion and subsequently differentiated in situ. Changes in petrography adjacent to pegmatite veins and textures within picrite units indicate compaction and filter-pressing were important processes after emplacement. Rhythmic layering (1 cm to 1 m thick) is conspicuous in the sills near contacts but does not involve cryptic mineral variation. Such modal layering may be more common than realised in relatively small-scale intrusions and maybe modelled in terms of in situ differentiation under conditions of significant undercooling in a changing thermal gradient at the synthetic for-sterite-diopside-anorthite eutectic.

Using geophysical borehole log signatures and basic lithological information from sidewall cores and well-cuttings, division and correlation of the mid-Cretaceous sediments of the Wessex Basin can be achieved. A sub-Gault (early Albian) unconformity surface is mapped with some accuracy across the Hampshire–Dorset area, and the deposits of a previous, Aptian transgression are observed. The distinctive log signatures aid in facies reconstructions and sequence stratigraphical analysis: especially the onlap of basal Gault horizons onto and across basement ‘highs’. The highly variable thickness and lithological distributions characteristic of the Wealden pass upward into laterally extensive facies distributions in the Lower Greensand and Gault. Sequence boundaries are identified at the base of the Wealden; Lower Greensand; Gault; within the Gault (cristatum subzone); and base Chalk.

Sm–Nd and K–Ar isotopic determinations on an amphibolite from the Highland Border Complex yield Cambrian ages. Collisional events which might have generated the amphibolite appear incompatible with the passive margin character of Laurentia at that time. A possible explanation is that the part of the Highland Border Complex containing the amphibolite and associated rock units was generated outside Laurentia.