The Dalradian Supergroup is interpreted traditionally as recording c. 300 m.y. of ‘episodic’ Neoproterozoic rifting. However, lower Dalradian (pre-Easdale Subgroup) facies architecture is incompatible with rift-basin fill, and no unambiguous Neoproterozoic extensional structures are present in those rocks. Consequently, no objective evidence exists to infer that Dalradian sedimentation was initiated during extensional tectonism. That, combined with the accumulating data for contractile deformation in Scotland at c. 870–800 Ma, the Knoydartian orogeny, permits the proposal of an alternative tectonostratigraphic evolution for the Dalradian. I propose that Dalradian basin genesis was initiated as a foredeep in response to Knoydartian orogenesis. The coarsening- and shallowing-upward, 6–8 km-thick Grampian Group–lower Lochaber Subgroup succession arguably represents a flysch to molasse Knoydartian foredeep overlain by a moderately stable post-orogenic shelfal sequence recorded by the relatively uniform thinner (c. 4 km) and compositionally more mature rocks of the upper Lochaber through Islay subgroups. Lithospheric-scale extensional tectonism and rifting did not occur until the late Neoproterozoic, as marked by the laterally variable, volcanic- and igneous-bearing Easdale Subgroup, and was followed by the late Neoproterozoic–early Palaeozoic Iapetan rift-to-drift transition through the Southern Highland Group.

An enigmatic buried structure, located in Mesozoic sedimentary rocks in the Perth Basin, Western Australia, was discovered in 1990 by Ampol Exploration. The basin-like Yallalie structure (centred on 30° 26′ 40.3″ S, 115° 46′ 16.4″ E) is circular in plan view and about 12 km in diameter. High-resolution, seismic-reflection profiles across the structure show a basin-shaped area of chaotic reflections that extend to a depth of approximately 2 km below the surface. The structure has sharp boundaries with surrounding faulted, but otherwise relatively undisturbed, rocks. In the centre of the structure there is an uplifted area approximately 3–4 km across, similar to those described from complex meteorite impact structures. The seismically defined structure coincides with a circular topographic depression, and image processing of digital elevation data has allowed recognition of concentric and radial structures extending as far as 40 km from the centre of the depression. Gravity surveys show the structure to be associated with a positive gravity anomaly of about 30 gu. Aeromagnetic surveys have defined annular anomalies associated with the central uplifted section, and possibly margins, of the structure. A search for siderophile element enrichments (by neutron activation analysis) in the rocks of the structure, which would indicate the presence of a meteorite component, proved negative. Quartz grains in cores that penetrate the structure show the development of prismatic cleavage fractures and irregular, slightly curved planes formed by brittle fracture. An allochthonous breccia of Late Cretaceous rocks occurs a few kilometres west of the western margin of the structure. Quartz grains from a thin veneer of Tertiary sediments that drape the structure are essentially undeformed. However, multiple sets of closely spaced planar deformation features in quartz, characteristic of highly shocked rocks, have yet to be observed in the rocks of the Yallalie structure and the allochthonous breccia. The morphology of the Yallalie structure determined from topographic and geophysical data suggests strongly that it is of impact origin. Geological and geochemical evidence is equivocal, but is not inconsistent with this interpretation.

Three elements of the ‘Ediacara fauna’ are described from lower Cambrian strata on the Digermul Peninsula, Norway. Nimbia occlusa Fedonkin, 1980 and Tirasiana sp. occur approximately 80 m above the base of the Lower Breivik Member, which approximately coincides with the Neoproterozoic–Cambrian boundary. A specimen of Cyclomedusa sp. has also been found in the Lower Duolbasgaissa Member about 600 m above the boundary, in rocks of trilobite-bearing age.

These discoveries add to a growing body of evidence that some elements of the dominantly Neoproterozoic Ediacara fauna continue into the Phanerozoic, thereby diminishing the scope of a possible late Neoproterozoic mass-extinction event.

The taxa described here, particularly Nimbia and Cyclomedusa, also occur at many other localities within Neoproterozoic strata and, in common with other elements of the Ediacara fauna, display remarkable morphological variation. Some of this diversity in form is probably caused by environmental and preservational factors. The possibility that it may, at least in part, reflect an inability of these early life forms to replicate faithfully their genes during reproduction should, however, not be overlooked.

Structural mapping from the Flat Belt into the Tummel Steep Belt of the Dalradian Supergroup of the Central Highlands provides evidence for a new interpretation of the relationship between the two belts and their evolution. The open upright D3 major folds of the Flat Belt intensify into the Steep Belt and are responsible for the steeper dips. These D3 folds refold four newly recognized D2 major folds. It is the recognition of the interference of these two sets of folds that leads to the radically revised structural interpretation presented here. A reconstruction of the pre-D3 structural history shows that the stack of major D2 folds, on the lower limb of the Tay Nappe, originally verged to the northwest, as did three D1 fold-pairs.

A model is proposed for the D2 deformation in a transpressional setting, simplified as partitioned into two sub-horizontal zones. The lower zone is represented by the pure-shear-dominated Tummel Belt with extension parallel to the regional orogenic trend; the upper zone is represented by the simple-shear-dominated Flat Belt where extension is perpendicular to that trend. The curvature of the minor D2 fold hinges supports a more refined model of smoothly continuous partitioning of transpressive deformation between the basement and high-level, southeast-propagating nappes above the Flat Belt.

Two metabentonite suites occur within the Wenlock limestones and marls of Gotland, one within the Slite Formation (M. belophorus to the C. ellesae biozones) and the other in the Mulde Formation (G. nassa–M. dubius Biozone). Their geochemical characteristics based on rare-earth element (REE) distributions in apatite crystals separated from the metabentonites suggest origins from three separate volcanic sources. One of these sources has an alkaline affinity, reflected in relatively high levels of Th, Nb and Zr, which suggests that it may have lain over thickening continental crust during the waning stages of the closure of the Tornquist Sea, while the other two represent calc-alkaline magmas. The source of the volcanic ash is placed some 400 km to the southwest of Gotland, on the Tornquist–Teysseyre Zone, which is the northernmost expression of the Trans-European Suture Zone. Distinctive differences in REE distribution in apatite from these metabentonites should assist in future correlation studies in Wenlock stratigraphy, both within the Baltic region and further afield.

Unusual mineralized and silicified carbonate-rich geodes were found hosted in Lower Triassic red mudstones in Central Spain. From their borders to their centres, the geodes display (a) a millimetric carbonate crust, (b) a quartz rim, (c) massive dolomite, (d) gold-bearing iron-rich infills (hematite laths and goethite with up to 7000 ppm of gold) and (e) calcite cements that sometimes seal the central hollow. Textural evidence indicates that the geodes were originally anhydrite, which was subsequently replaced by quartz and dolomite. The resultant porosity from this replacement, or by later dissolution, has been filled by epithermal gold-bearing iron-oxide hydroxides, romanechite and calcite.

δ13C values indicate the participation of meteoric waters in an environment which was characterized by both a sub-desert climate and a temperate–tropical climate. Oxygen signatures reflect very variable temperatures for all minerals, with the exception of calcite, which appears to have precipitated at <38°C. Iron-oxide temperature values can reach up to 85°C (epithermal stage). The mineralogical assemblages of these unusual geodes denote early diagenetic replacement followed by the epithermal activity. This mineralization is linked to the Late Hercynian, calc-alkaline volcanism of Central Spain (the Hiendelaencina mining district).

The mid-Cretaceous sediments of northeast England were deposited at the western margin of the southern North Sea Basin, with sedimentation occurring in a range of tectonic settings. Detailed analysis of the areal distribution and sedimentary facies of Aptian to earliest Cenomanian sediments has allowed the pattern of onlap onto the Market Weighton structural high and changes in relative sea level to be documented. Successive onlap episodes during the Early Aptian, Late Aptian and Early Albian culminated in the final flooding of the structure during the Late Albian (varicosum Subzone). Sea-level curves generated from coastal onlap patterns are difficult to relate to published ‘global’ sea-level curves due to the high frequency of the fluctuations in relative sea level observed. Despite this, detailed correlation and analysis of sedimentological events suggest that even the most expanded, basinal succession is relatively incomplete. This study has also shown that the change from dominantly syn-tectonic to dominantly post-tectonic sedimentation style occurred in the late Early Albian.