Despite their importance and frequency of usage, ‘grouping terms’ in petrology such as Association, Family, Lineage, Province, Series and Suite appear to lack established meanings. Partly by analogy with the recently standardized stratigraphic nomenclature, hierarchies of such terms are suggested to cover petrographic classification (rock-names), petrological classification (rock-names extended to magma-types), geographic classification (igneous provinces) and tectono-genetic classification (rock assemblages characteristic of particular tectonic regimes). Used in this way, the exact implications of each term become clearer. Again by analogy with stratigraphy, ‘Super-’ and ‘Sub-’ groupings are suggested in a few cases: ‘Subprovince’ for example can differentiate distinct rock assemblages related to separate parent magmas within one well-defined Province (e.g. nephelinite-carbonatite and basalt-trachyte assemblages in the East African Rift), and ‘Superprovince’ can be used to group coeval Provinces now separated by opened oceans, etc. (e.g. Thulean Superprovince composed of Hebridean, East Greenland, etc., Provinces). The term ‘Province’ itself carries several ambiguities; it is best confined to cases where the ages of the spatially associated igneous rocks fall within a narrow range (e.g. Oslo Province); ‘Belt’ is suggested for those where the age-range is more substantial (e.g. Jurassic-Tertiary magmatism of Southeast Brazil).

The current belief in a single chalky till glaciation of eastern England is upheld by a detailed examination of a section at Barrington which had been said to reveal two such tills. An attempt is made to arrange the glacial, periglacical and interglacial beds of southern Cambridgeshire into stratigraphic order and to place them within Quaternary stages. The study concludes with a consideration of the fabric data that were used to support the claim that two major chalk-rich tills occur in East Anglia. Till mineralization is reported in the area for the first time.

Pelitic schists from the Appin Group of the Dalradian Supergroup are all chemically distinct from pelitic schists in the older Moinian Supergroup. In addition, trace-element geochemistry can also discriminate between the individual pelitic schists within the Appin Group, especially those within the Lochaber Subgroup. These differences apparently relate mainly to differences in provenance rather than differences of sedimentary environment, and are sufficiently consistent to offer a means for correlation or identification of pelitic units in areas of the Central Highlands where the stratigraphy is still in dispute.

Preserved in the deformed peridotites of the Lizard, Cornwall, are relics of intricate primary precipitates of olivine. The mineral compositions of those rocks with an abundance of primary relics are typical of the primary assemblage Lizard peridotite. In detail the olivine primary structures resemble, but are not identical to, the crescumulates described from various layered ultrabasic intrusions. The available evidence shows distinctive specific features in the Lizard crescumulates in the scale and morphology of the structures and in the conditions of growth.

The Keystone/Muddy Mountain thrust of South East Nevada provides a spectacular example of a thrust sheet that has travelled across the earth's surface for a distance of at least 25 km, probably as much as 50 km. Along the thrust a Palaeozoic to early Mesozoic succession (> 4 km thick) has moved over a channelled erosion surface cut into Jurassic aeolian sandstone. Clasts in the channels are stratified, with those in upper layers being easily matched with the rocks in the thrust sheet – thus the clasts ‘herald’ the approach of the sheet. The clasts are only weakly deformed by the thrusting which belongs to the Sevier-Laramide orogeny.

Erosion appears to be a significant if not crucial factor in the emplacement of the Keystone thrust sheet. Adopting an erosion rate of 1 mm/a (in accord with Alpine and Himalayan estimates) and a rate of thrusting of 5 mm/a (in accord with estimates from the Canadian Rockies) it follows that the thrust sheet was ‘half-eroded’ after travelling about 25 km.

It is concluded that large displacement (i.e. > 25 km) may be impossible without erosion and one of two ‘erosion models’ would greatly facilitate transport up to 50 km, which is the likely maximum displacement.

New observations of sedimentary and tectonic structures confirm ‘pre-cleavage’ folding of the Arenig Loweswater Flags and Kirk Stile Slates. A major recumbent fold is thought to have developed by gravity gliding during Arenig-Llanvirnian times.

A brachiopod fauna is described from a marine horizon within the Dartmouth Beds at Bull Cove, Cornwall. The fauna indicates a Middle or Late Siegenian age and aspects of the palaeoecology are discussed. The Lower Devonian succession of south Devon and north Cornwall is discussed and the terms Meadfoot facies and Standon facies are proposed to replace the Meadfoot Beds and Staddon Grits of the old terminology.

The Sulitjelma Gabbro, occurring as a member of the Sulitjelma Ophiolite Complex, and typical of the ophiolite suite in its petrography and geochemistry, is cut by a vein of trondhjemite (plagiogranite). The previous identification of the vein as an offshoot of a continental potassium-rich granite, the Furulund Granite, is wrong. Therefore the Rb-Sr isochron age of 413±34 Ma, obtained from the granite, cannot be taken as the age of intrusion of the Sulitjelma Gabbro.

Computer-enhanced Landsat images reveal a 65 km arcuate lineament linking the concealed fault zone beneath Wadi Al-Batin to the central Arabian graben and trough system. Detection of the link allows a continuous 1000 km arc of faults and troughs cutting the Mesozoic-Cenozoic rocks of the Arabian Shelf to be recognized. The arc, here called the East Arabian fault zone, is interpreted as forming the western and southern boundaries of the East Arabian block, a tectonic unit underlying at least 200 000 km2 of the Arabian Peninsula.

Stratigraphical relationships within the 560 km central Arabian graben and trough system demonstrate that its faults were active during the late Cretaceous-early Palaeogene, movements ceasing when the Red Sea began to open and the Arabian subplate was established. The principal hydrocarbon fields of the Arabian Peninsula lie within the boundaries of the East Arabian block.

At the base of austroalpine nappes in Calabria alpine greenschist dynamometamorphism is overprinted by blueschist metamorphism. Tectonic overpressures and deep-rooted movements of upthrusting type in compressive regime are the key to generation of blueschistic conditions and to greenschist-bluecschist evolution of metamorphism. The tectonic overpressures are generated because the rocks at higher confining pressures and lower pore pressures have relatively higher resistance to deformation. The evolution from greenschist to blueschist conditions results from cooling during upward motion with overpressures remaining concentrated along the thrust zones.

Geochemical stream sediments and bed-rock surveys were carried out on an area of about 400 km2 in the Muelha-Dungash area. Results indicated that Sn and Nb anomalies are concentrated near Gabal Mueilha and are related to the greisenized and albitized granites. Disseminated-type and vein-type gold mineralizations occur in propylitized granodiorites and quartz veins at Samut. Cu anomalies show wide distribution, with a large proportion confined to the central and southwestern parts of the district, where signs of hydrothermal alterations are clear. Most of the Cu, Sn and Nb anomalies coincide with ‘deep-seated tectonic zones’ having the direction of the Red Sea Rift System, which are characterized by anomalous radioactivity and intense metamorphism as well as metasomatism and mineralization caused by acidic intrusions. Under the arid conditions of the Southeastern Desert of Egypt, stream sediments and bed rock surveys proved to be suitable methods of prospecting.

Some commercial silicone (Dow Corning Silastic E, J) and PVC (Dugdale DD 118) synthetic rubbers make excellent casting materials for the production of high-fidelity replicas of fossils from complex natural cavities. The methods described avoid tearing of the cast and damage to the mould.

The occurrence of Barroisiceras within the top bed of the Zone of Holaster planus near Dover in Kent provides the first ammonite evidence for the position of the base of the Coniacian in the Chalk of England. Inoceramus cf. rotundatus occurs ½ m above the ‘Top Rock’.