The distribution of andalusite, kyanite and sillimanite in an important part of the NE Dalradian is mapped. Sillimanite represents a late episode overprinted on the regional Andalusite and Kyanite Zones. The spatial distribution of sillimanite confirms that the heat source for the sillimanite-grade metamorphism in this area was the Newer (or Younger) Basic magma. The sillimanitic aureole of the Newer Basic intrusives is divisible into a Sillimanite Zone and a higher-grade Sillimanite—potash feldspar Zone. Relict andalusite is common in the Sillimanite Zone. Coarse muscovite replacing other minerals is primary in both zones, and should not be confused with late retrograde effects. Electron-probe analytical data on the Sillimanite–potash feldspar zone paragenesis of muscovite are presented. In this, its type area, the so-called ‘Boyne Line’ does not exist; the concept of such a tectonic dislocation arose through misinterpretation of the metamorphic effects.

The regional strike of the bedding and foliation is NW but most of the folds and lineations plunge roughly SW. Lineations that resemble grain (longrain) seem to be usually parallel to the steeply plunging fold axes. This structural pattern occupies more than 2,000 km2. The formation of this pattern of folds was preceded and succeeded by regional folding along horizontal axes.

Hopen (Hope Island) in the Svalbard archipelago is difficult of access and only recently has reliable geological information become available. Published information is reviewed and combined with new observations.

The island, 37 km long and no more than 2.5 km wide or 370 m high is structurally simple with flat-lying arenaceous strata which are described with three measured sections. Three new local stratal units are defined: Iversenfjellet Formation (325 m, base not seen); Flatsalen Shale Formation (55 m); and Lyngefjellet Sandstone Formation (80 m, top not seen).

From a few ammonite, bivalve, saurian and plant megafossil occurrences and 30 palynomorph taxa (newly recorded) the marine and fluviatile facies range in age from possibly late Karnian, through Norian, Rhaetian and possibly into early Jurassic. The Rhaetian flora, well established palynologically, is the first clear evidence of rocks of this age in Svalbard. Associated Sirenites extends the range of this ammonite and suggests that Svalbard may yield significant new evidence for this span of Earth history.

Sediments from 6 localities showing negligible deformation are described from a generally strongly deformed formation of metasediments. The tidal flat facies include decimetre-thick tabular sands, interpreted as the flood tide storm deposits of subtidal to intertidal channels, as well as centimetre to millimetre thick, rippled and laminated sands and silts with gypsum pseudomorphs. The gypsum crystals grew at interfaces where more permeable, overlaid less permeable, sediment and then underwent partial solution before being replaced by ferroan calcite and quartz. The shallow marine facies are centimetre-thick rippled sands interbedded with muds, interpreted as storm sediments.

Four mineralogical zones, corresponding to the following ‘maximum’ metapelitic assemblages

zone 1: chloritoid-chlorite-kyanite

zone 2: staurolite-chloritoid-chlorite-kyanite

zone 3: biotite-staurolite-chloritoid-chlorite-kyanite

zone 4: biotite-staurolite-garnet-chlorite-kyanite

have been mapped in the Ultrahelvetic rocks of the Lukmanier area in Switzerland. Petrographic study suggests that, despite the ubiquity of ‘disequilibrium’, the zone boundaries accord with the simple univariant equilibria

chloritoid+kyanite = staurolite+chlorite+quartz+H2O

chloritoid+chlorite+muscovite = staurolite+biotite+quartz+H2O

and chloritoid+muscovite+quartz = staurolite+garnet+biotite+H26

Using structural contours, minimum isogradic dips of 35° north have been obtained.

The Lukmanier parageneses require the Lepontine phase of Alpine metamorphism to have had a geotherma! gradient distinct from both Alpine blueschists and the Bergell contact metamorphites. The high minimum value for isograd and isotherm orientation here points to a convective heat source for the Lepontine event.

Late Precambrian (∼ 750±200 Ma) glaciogenic sequences exhibit substantial evidence for marked climatic inequability of seasonal and longer periodicity (10° to ∼ 106 yrs): (1) tillites are closely associated with dolomites, limestones and evaporites apparently of warm-water origin; (2) tillites occur with red beds and iron-formations whose iron probably was derived ultimately from lateritic weathering; (3) glacial dropstones occur locally within carbonates and iron-formations; (4) laminae, interpreted as varves by many workers, are common in argillites, carbonates and iron-formations; and (5) permafrost structures attributable to repeated seasonal changes of temperature are locally abundant. Such climatic, particularly seasonal inequability apparently conflicts however with the probable low (≲30°) palaeolatitudes of deposition of numerous late Precambrian glaciogenic sequences.

The contradictions presented by such sequences may be resolved by postulating a considerably increased obliquity of the ecliptic (ε) in late Precambrian time. Substantial increase in e would: (1) greatly amplify global seasonality; (2) weaken climatic zonation, thus allowing warm-water sedimentation and lateritic weathering over wide latitudes; and (3) increase the ratio of radiation received annually at either pole to that received at the equator, so when 54° < ε < 126° low and middle latitudes (≤ 43°) would be glaciated in preference to the poles. Ice sheets and permafrost thus can be envisaged principally in low and middle latitudes with contiguous warm-water and iron-rich facies under a markedly seasonal climate. The concept of secular change of e is supported by other geological evidence.

Textural patterns characteristic of supposed pre-, post- and to a lesser extent syn-tectonic porphyroblasts are reviewed. Difficulties of interpretation arise where an Si (internal schistosity) is absent, and Se (external schistosity) behaviour adjacent to porphyroblast margins is the only available criterion; examples may be found showing truncation of Se by pre-Se porphyroblasts. Truncation and/or deflection textures are not by themselves sufficient criteria for determining the time relations of particular phases of deformation and crystallization.

The evolution of Neogene volcanic activity in the Central Taurus is investigated; stratigraphical and radiometric age data from the Ürgüp (Kayseri) basin idicate that volcanism in the area began at least as early as Upper Miocene, lasting up to prehistoric times. The volcanism maintained throughout this time interval a calcalkaline character. The diachronous end of calcalkaline volcanism along the Taurus margin is tentatively related to the differential collision between the Afro-Arabian and the Anatolian plates, probably due to an original irregular shape of the Anatolian continental margin.

It is suggested that post-(Hercynian)orogenic tensional forces may have initiated a major rift valley system in the Palaeozoic rocks of southern Britain. Large graben structures may underlie the Bristol Channel, the Severn Basin and the Weald Jurassic trough. Smaller graben structures are present in Devon and are associated with extrusive, potassium-rich lavas. The bounding faults of the larger postulated grabens may have been active during early Mesozoic times and may have fundamentally controlled sedimentation in local sags. A model is proposed which ascribes the development of fault-bounded Permo-Triassic basins and Jurassic axes of uplift to fracturing in the Palaeozoic basement.

Granitic rocks in the central Transantarctic Mountains were emplaced and crystallized during the Early Ordovician Period, as indicated by Rb-Sr whole-rock isochron dates (488 and 463 Ma) and a concordant U-Pb date on sphene (476 Ma). Other U-Pb data provide evidence for an old inherited component of zircon in the granites.

Three new species of Marsupiocrinus are described from the basal Wenlock Laurel Limestone of southeastern Indiana. Although the earliest representatives of the genus yet known, they display fully the specialized characters peculiar to it. Two new subgenera of Marsupiocrinus are erected on the basis of arm structure and cup shape.

Recent collections of graptolites from the Călărasi, Ianca-Berlescu and Tăndărei boreholes have helped to refine the stratigraphy of Silurian (Wenlock, Ludlow) and Devonian rocks of the Moesian Platform. Fourteen species are recorded for the first time from Rumanian strata, others are left under open nomenclature, whilst well-preserved specimens of the following species provide additional information on their detailed morphology and hence upon their relationships and evolution: Monocliniacis sp., Holoreriolites (Balticograptus) cf. balticus Eisenack, Saetograptus cf. rams (Teller), Monograptus kolihai Bouček, ?Cyrtograptus sp., Barrandeograpus pulchellus (Tullberg), and ?Neodiversograptus ex gr. nilssoni(Barrande).

The ichnogeneric status of trilobite furrows (Cruziana) and resting excavations (Rusophycus) is discussed and the suggestion (Seilacher, 1970) that these two distinct types of trace should be united under the genus Cruziana is rejected.

The tectonic evolution of Nigeria's Benue Trough has recently been the focus of investigations, especially in relation to continental drift and opening of the South Atlantic Ocean during Cretaceous times. Most of the tectonic models presented for the Benue depression have placed undue emphasis on certain plate tectonic concepts which are inconsistent with the salient geologic features of the trough. A possible model, involving the rise and cessation of mantle upwelling beneath a Cretaceous hot spot, and attendant patterns of doming, rifting, sedimentation, magmatism and tectonism, is proposed for the Benue aulacogen.

Measurements have been made on drumlins from the Glasgow district and eastern Westmorland, using 1:25000 topographic maps and direct field mapping. Comparison of the results suggests that topographic maps provide data which varies in accuracy with the clarity of the drumlin pattern depicted by the map, and the character of the particular descriptive parameter. Dimensionless parameters such as elongation ratio, tapering value (k), and stoss-point ratio are most accurately estimated, but size, spacing and density are consistently inaccurate, and the number of drumlins recognized is, at best, only 50 % of the number of drumlins that exist in the field. It is suggested that topographic maps fail to give information at the precision level required for the analysis of this type of glacier bedform.

Stratigraphic sections measured at Wilhelmøya and Hellwaldfjellet in eastern Svalbard are described in their entirety in terms of formal lithostratigraphic units for the first time. They include rocks of mid-Triassic to late Jurassic age. The Uleneset Member is newly described and palynological evidence is used to show that it is largely Norian (late Triassic) in age.

Kaolinite is the major mineral in the saprolite of a fossil laterite, found intercalated amid basalt flows from the Lower Cretaceous in the Negev desert. The kaolinite was produced by pseudomorphic alteration of plagioclase. Haematite is a secondary product and accumulated in a ferruginous soil horizon. In the saprolite Sr, Mn and Cu were strongly depleted, Zn and Ni were slightly depleted, whereas Co and Cr accumulated. In the ferruginous horizon, Sr, Mn, Cu and Zn were severely depleted, while Cr and Ni accumulated. The lateritic formation is evidence for the possible existence of tropical or intertropical conditions during the Lower Cretaceous in the Negev.

A general model for pedogenic carbonate development in alluvial sediments is based upon of rates flood sediment accretion versus time taken for particular carbonate profiles to develop. Conclusions regarding rates of Holocene carbonate pedogenesis and the changing morphology and thicknesses of carbonate profiles with time are used to predict critical values of floodbasin accretion rates which would have enabled particular ancient profiles to develop. Local (intra-drainage basin) and regional profiles are separated and a number of models for calcrete genesis are outlined. The presence or absence of particular genetic stages of calcrete may be used as a rough guide to estimate ancient floodbasin accretion rates.

Pollen analyses from sediment adhering to fossil mammalian bones from Barrington, Cambridgeshire, have demonstrated that the deposit is of Ipswichian zone IIb age. This is also indicated by the mammal fauna. Herb-dominated communities, which appear to have been largely maintained by the activities of herbivorous mammals, grew locally on the river floodplain, whilst temperate mixed-oak forest was present further away.

The geology of Barbuda, a low-lying island in the Lesser Antilles, is reexamined and the stratigraphy is revised. The oldest rocks are limestones of the Highlands Formation, a Middle Miocene accumulation of fore-reef facies. This is overlain successively by the Pleistocene Beazer and Codrington Formations, limestone accumulations of reefal, lagoonal and dune facies. The Holocene Palmetto Point Formation is comprised of extensive beach ridge and dune limestones. From this, the Barbuda Bank (which includes Antigua) is considered to have had a geological history like the neighbouring Anguilla and Guadeloupe Banks.