In northeastern Spitsbergen and western Nordaustlandet well preserved Late Precambrian diamictites have variously been interpreted as tillites or the product of tectonic activity. By focusing on the sedimentology of the diamictites in two key areas, this paper presents unequivocal evidence that the diamictites are indeed glacigenic, confirming the conclusions of previous field investigations. In particular dropstones in large numbers and striated stones are diagnostic of glacial transport, while other characteristics are strongly suggestive of glacial conditions.

Stratigraphic studies indicate two discrete glacial episodes, both belonging to the Varangian epoch. The earlier resulted in a thin tillite sequence deposited in a shallow shelf-tidal-lacustrine environment. It is closely associated with stromatolitic dolostones. The later episode resulted in a tillite sequence a few hundred metres thick with two units in northeastern Spitsbergen separated and bounded by dolostone units. Deposition occurred in a shallow marine environment but occasional uplift led to terrestrial conditions and the deposition of fluvioglacial sediments and the development of periglacial phenomena.

The weathering of a suite of basalt clasts, that have been transported by mass wasting downslope in the Cumulus Hills region of the Queen Maud Mountains, Antarctica, is examined from both geochemical and glacio-geomorphic viewpoints. Chemical weathering, predominantly oxidation and hydration, increases in severity from clast core to rim for the suite. These weathering processes and concomitant formation of a weathering rind are suggested to be an accumulative process, culminating in the disaggregation of the rock due in part both to the chemical breakdown of the interstitial and intersertal basaltic glass and to physical weathering processes.

Mass wasting rates in the range of 1.4 × 10−3−1.13 × 10−1 cm. y−1 are estimated, assuming that the style of transport is dry creep. These transport rates suggest that the rock-surface/air-temperature differences in the study area may have been as little as 0.5 °C and heating and cooling cycles as few as 1 cy. y−1 for the last 4.2 Ma.

Large deposits of marine-sand occur in the Taw, Camel and Hayle estuaries of north Devon and Cornwall. Total carbonate concentrations reach 67% in the Hayle, 62% in the Camel, and 40% in the Taw. Well mixed, the sands contain modern skeletal debris of consistent composition, which persists up to 18 km and 12 km landward from the mouths of the Taw and Camel estuaries. Although primarily a molluscan sand, remains of barnacles, bryozoans, echinoids, foraminifera, sponge spicules, decapods and coralline algae are common. Carbonate mineralogy provided by these components (on a 100% carbonate basis) consists of 45% aragonite, 38% low Mg-calcite and 17% high Mg-calcite. Two estuaries of the southeast coast of Devon (the Exe and Teign) contain smaller carbonate concentrations of up to 9 and 14%. Values are low there owing to dilution by readily eroded cliff-talus from local exposures of New Red Sandstone. These Permo-Triassic sediments provide carbonate lithoclasts, however, which supplement the modern biogenic supply. Strontium values have been used to estimate the extent of carbonate lithoclasts supplied to the Exe and Teign. The present source of marine-sand of estuaries in southwest England is considered to be mostly near-shore detritus supplemented by eroded cliff-talus, derived largely from local outcrops. Once this material enters the estuarine regime it is available as a supply of sediment for further up-estuary transport.

Abundance data, determined by epithermal neutron activation analysis, are reported for radioelements in the northern units of the Leinster granite. Compared to similar data for silicic igneous rocks and British Caledonian granites, the Leinster granite shows normal U and K contents but is low in Th. Inter-element correlations and fission-track results suggest that most Th and up to 40% of the U is bound in resistate accessory phases (zircon, sphene, apatite), but that the bulk of U is associated with late-stage alteration products and is located at interstitial labile sites within the host-rock matrix. Mobilization of U located at such sites in the Leinster granite by hydrothermal leaching could lead to redeposition and enrichment in marginal sediments of Old Red Sandstone or younger age.

A freshwater and land molluscan assemblage from an Ipswichian stream channel at Maxey, Cambridgeshire, is discussed. The presence of Belgrandia marginata and Vallonia enniensis suggests that summer temperatures may have been somewhat warmer in the Ipswichian period. The assemblage represents the silting processes under relatively quiet water conditions, possibly in a side channel or backwater of a meandering river system.

Rb-Sr analyses of syntectonic single-crystal garnets from the Svartsobacken and Dikanas schist units of the Seve Nappe, Scandinavian Caledonides, show systematic differences. One group yields a Precambrian age spectrum consistent with that given by whole-rock analyses; the other group gives Caledonian ages similar to those given by mica analyses. It follows that the tectonic events reflected in the garnet inclusion patterns are also of different ages and, subject to certain limitations, the method can be used to provide a clearer interpretation of the deformational and metamorphic history of the rock.

Natural pyroxene spinifex-textured rocks, free of olivine, may have MgO contents as high as 15%. If these rocks are allowed to crystallize in the laboratory under equilibrium conditions, olivine is the liquidus phase at 1350°C and pyroxene does not appear until the temperature has fallen to 1180°C. A similar problem is encountered in high MgO komatiites. If spinifex-textured and aphyric komatiites from Munro Township are plotted on an MgO-CaO-Al2O3 diagram, olivine control is evident until the MgO content of the melt falls to 15%. At this point the liquid trend moves away from the CaO-MgO boundary, indicating the crystallization of pyroxene. If a high MgO komatiite is crystallized in the laboratory under equilibrium conditions, pyroxene does not appear until the MgO content of the liquid reaches 9%. It is suggested that experimental and natural systems behave differently because pyroxene has crystallized metastably in the natural system under conditions of extreme supercooling. The early metastable crystallization of pyroxene can only affect the liquid trend if the spinifex zone contains a cumulate component.

Echinoderm plates from the Protolenus Limestone are recognised as belonging to three groups; plates with folded surfaces, plates with bevelled edges and a third group. They are not comparable with other Lower Cambrian echinoderms and may be derived from a genus or genera of eocrinoid which is not known from complete specimens.