The relatively well preserved, 42 km diameter lunar impact crater Aristarchus was excavated across the boundary between the Aristarchus Plateau and the mare plains. Previous geological mapping of the different ejecta facies associated with Aristarchus has shown that there are distinct morphological differences between ejecta emplaced on either side of the fault scarp that separates the plateau from the mare. One explanation of this observation is that ejecta behaved in different ways on emplacement depending on the original lithology of the excavated material. To test this proposal, we examine the pre-Aristarchus regional stratigraphy and identify the spectral signatures of each of the material's units. By comparing these data with analysis of the geology and spectral characteristics of the ejecta units, we are able to show the provenance of each of the mappable ejecta facies. The conclusions are consistent with the concept of the crater ejecta asymmetry being related to bedrock characteristics. Using geological mapping, spectral interpretation and present understanding of the impact cratering process, we reconstruct the impact event and suggest how such techniques could be used further to interpret the Moon's composition and history.

Large Dictyonema species, including D. pulchellum T. S. Hall, have been collected from beds in the Uldale Fells (northern Lake District), below strata yielding Didymograptus protobalticus Monsen. They suggest the presence there of graptolitic beds transitional from Lancefieldian to Bendigonian in age (approximately Tremadoc-Arenig) and suggest that the area may yet provide an internationally correlatable base to the Arenig Series in Britain.

A 22 m thick primitive, basanitoid sill comprises homogeneous olivine teschenite, overlain by picrite and a rhythmically layered sequence of olivine teschenite, salitic teschenite and syenite. Differentiation occurred in two stages by fractional crystallization, in part from melt residual from formation of picrite. Syenitic blebs and hydrated globules, occurring through the layered sequence, formed by the same mechanism rather than by immiscibility. Endothermic cindering of a small coal seam below the intrusion absorbed heat and steam from the sill, removing volatiles from the lower part and establishing a strong downward heat flux. The picrite was restricted to the upper part of the sill by more rapid cooling of the lower half.

A new and well-preserved.asteroid, Protremaster uniserialis (gen. & sp.nov.) is described from the Lower Jurassic (Sinemurian) of Antarctica. This find extends the fossil record of the family Asterinidae and the subfamily Tremasterinae considerably and lends support to the idea that asteroids underwent an important morphological diversification in the late Triassic-early Jurassic.

The composite dyke at An Cumhann, Arran consists of a central unit of quartz-feldspar porphyry flanked by narrow marginal dolerites containing xenocrysts of quartz, plagioclase and alkali feldspar identical to the phenocrysts in the porphyry. The chemistry of the marginal dolerites indicates that they formed by the crystallization of a hybrid magma produced at depth by the incorporation of the porphyritic acid magma in a basic liquid. During the intrusion of the hybrid magma, flow caused a differential distribution of the xenocrysts across the initial basic dyke. Subsequent intrusion of the quartz-feldspar porphyry magma along the still unconsolidated centre of the basic dyke produced the wide central unit. A similar origin is proposed for other composite intrusions of the same type in the region. Whilst it is unlikely that the coexistence of the highly contrasting magmas necessary for the formation of these intrusions is entirely coincidental there is little likelihood that the two liquids were related as members of the same fractionation series.

Intertidal molluscs are known to occur in similar positions or zones on shores throughout the world. However, little is known about the extent to which these distributions are preserved in the fossil record. This study attempts to define the relationship to present sea level of live and dead intertidal molluscs in the Mediterranean, and utilizes this information to interpret the position at which Quaternary shorelines were formed.

The preservation of zonation patterns in the fossil record is affected by post-mortem transport, breakage and burial of the shell material. To take account of such taphonomic changes, experimental studies of shell transport and burial under waves and unidirectional currents were made, and the distribution of dead molluscs on modern shores were compared with live distributions. It proved possible to predict the frequency with which certain species were deposited on the modern shore and, by analogy, the likelihood of their preservation in the fossil record. Thus death assemblages in fossil shorelines can be accurately related to past sea levels.

Palaeomagnetic data from mid to late Palaeozoic rocks are potentially valuable for testing models of the assembly of Spitsbergen and for determining the palaeo-position of parts of Spitsbergen relative to the major tectonic elements that comprised the Old Red Continent. Fine-grained red sandstones from the Tournaisian to Namurian Billefjorden Group, collected by members of Cambridge Spitsbergen expeditions, were subjected to stepwise chemical and thermal demagnetization. The characteristic magnetization is found in normal and reverse polarities and corresponds to a pole position at 23° S, 332 °E, dp = 5.7°, dm = 10.5°, which is near an early Carboniferous pole computed for the Baltic Shield-Russian Platform (Baltica). When compared to Laurentia (North America) in the context of the revised Mauch Chunk palaeomagnetic study, Spitsbergen falls a few degrees south of the Bullard reconstruction but the error of the determination of the palaeolatitude overlaps with this position. Therefore relative motion between any part of Spitsbergen and Laurentia and Baltica during the Carboniferous is not resolved.

The Whin Sill comprises a major quartz tholeiite sill of late Carboniferous age underlying an area of c. 5000 km2 and with a volume of c. 200 km3, associated with contemporaneous dykes emplaced within Carboniferous sedimentary rocks in northeast England. New trace element analyses of chilled margins, sill interiors and dykes indicate that the Whin Sill complex magmas show significant chemical variations in terms of the relatively stable trace elements Th, Ce, Y, Zr, Nb and Ni. These data indicate that the complex was fed by a large number of compositionally distinct magma pulses, and that certain of the dykes may have formed feeder channels for the sill. The chemical characteristics of the sill and dyke samples are consistent with derivation by extensive polybaric fractional crystallization of olivine tholeiite magma derived by partial melting of compositionally heterogeneous mantle peridotite and/or crustal contamination of mantle-derived magmas.

A simple seismic refraction line some 115 km long has been made across Norfolk to provide constraints on the depth to the ‘igneous/metamorphic’ basement. Shots were fired in the Wash and off the coast near Lowestoft and attempts were made to record at approximately 2 km intervals along the line. Recording quality was only fair, resulting in incomplete coverage of the line, and this restricts the quality of interpretation. The results show a refractor of about 6.05 km s−1 revealed over the whole line with no first-arrival evidence of the 4.5–5.5 km s−1 velocity expected from Palaeozoic sediments. Using estimated velocities of 2.4 km s−1 for the post-Palaeozoic succession, 4.5–5.5 km s−1 for the Palaeozoic succession and an estimated sub-crop position of the basement on the sub-Mesozoic floor, models are produced which suggest that the Palaeozoic sediments are no more than 600–1500 m thick at the eastern end of the line, depending on the Palaeozoic velocity assumed.