A saccoderm desmid Mesotaenium berggrenii forma (Mesotaeniaceae) occurring as a major component of the snow algal flora is reported from the Windmill Islands region of Continental Antarctica. Stages of the life cycle of the species are illustrated. The local distribution of the species is outlined, habitat conditions described, taxonomy, reproduction and survival strategies discussed. Morphological and nuclear size classes indicate the possibility of polyploidy in the species.

At Radok Lake, northern Prince Charles Mountains, more than 2500 m of Permian Amery Group strata in the Beaver Lake graben are downfaulted against a Proterozoic metamorphic basement. An irregular blanket of late Cenozoic Pagodroma Tillite, up to 100 m thick, overlies the Permian strata and Proterozoic basement. The metamorphic basement comprises repeatedly deformed, high-grade felsic, mafic, aluminous and minor calc-silicate rocks derived from igneous and sedimentary precursors. Low- to medium-pressure granulite-facies metamorphism, assumed to be the ~1000 Ma event widely recorded in the East Antarctic Shield, was followed by incipient to moderate amphibolite-facies retrogression. Three folding events are recognized. Sporadic occurrences of pseudotachylite in the basement represent seismic faulting after substantial uplift and erosion. At the southern end of Radok Lake the Permian coarse alluvial fan facies, the Radok Conglomerate, is overlain disconformably by the Dart Fields Conglomerate, a basal member of the Bainmedart Coal Measures. Five kilometres along strike the deltaic Panorama Point beds, containing sideritic ironstone strata, are overlain conformably by arkosic sandstones of the basal Bainmedart Coal Measures. The Amery Group is intruded by two alnöite sills and at least five altered alkaline mafic dykes. The Pagodroma Tillite contains reworked marine microfossils and records the erosion of higher latitude Cenozoic marine sequences by an expanding ancestral Lambert Glacier.

A geophysical data set including some 1400 km of reflection seismic profiles and 17000 km of gravity lines was recorded in the waters north-west of the Antarctic Peninsula during the austral spring cruise of RV Polarstern (October to December 1987). These data form a contribution to the earlier and continuing studies dealing with the tectonics of Bransfield Strait, the structure of the South Shetland Trench, and the segmentation of the adjacent oceanic crust. The seismic profiles and gravity data illustrate among other features the differential extension of Bransfield Strait and the structure and morphology of the former converging plate boundary, which vary corresponding to the time of the last ridge trench collision. Observations have been made about the active character of several oceanic fracture zones in time which meet the former plate boundary.

The petrography and mineralogy of Iherzolite nodules from an intrusive body of alkaline-ultrabasic rocks on Jetty Peninsula. The nodules are massive with a porphyritic hypidiomorphic granular texture. The main rock-forming minerals are: olivine, pyroxene, garnet and chrome spinel. The nodules are coarse granular spinel-garnet Iherzolites that are chemically similar to pyrope peridotite from Krezemze, Czechoslovakia, and pyrope-bearing peridotite from alkaline ultrabasites of Yakutia, USSR. The Al2O3 content in enstaties and Ca/(Ca + Mg) ratio in co-existing chrome diopside suggest that equilibrium conditions of the mantle mineral assemblage are: T = 875–900°C, P = 20–24 kbar, conditions typical of the spinel-pyrope facies of the upper mantle. Depths of withdrawal of the inclusions do not exceed 60–75 km. Available age determinations of the intrusive alkaline-ultrabasic rocks (145–150 Ma) suggest that alkaline-ultrabasic magmatism and withdrawal of plutonic nodules were related to rifting which resulted in the breakup of the Gondwana supercontinent in the late Mesozoic.

Isolated fish remains including a tooth of the oldest described frilled shark, Chlamydoselachus thomsoni sp. nov. are described and figured from the Santa Marta Formation (Santonian–Campanian, Late Cretaceous) of James Ross Island, Antarctic Peninsula. Their geological and palaeoecological context is considered in the light of recent geological studies.

A preliminary palynological study of Beacon Supergroup sedimentary rocks exposed at Milorgfjella, Dronning Maud Land, has yielded a relatively rich and well preserved palynoflora dominated by spores and pollen grains, but also including acritarchs and green algae. The palynoflora is dominated by the pterophyte spores Punctatisporites gretensis, Punctatisporites parvus, Granulatisporites spp., Microbaculispora tentula Horriditriletes spp. and Verrucosisporites andersonii, and the gymnosperm pollen grains Plicatipollenites spp. and Cannanoropollis spp. Also present are the lycopod spore Jayantisporites pseudozonatus, the praecolpate pollen grain Marsupipollenites striatus and the monocolpate pollen grain Cycadopites cymbatus. The palynoflora indicates freshwater conditions or, at least, a major freshwater influence on the depositional environment. Comparison of the palynoflora with others from Gondwana suggests an Early Permian (Asselian–Sakmarian) age.

The fluorescent neutral lipid stain, nile red, was used to examine cell-specific neutral lipid levels in natural assemblages of Antarctic sea ice microalgae. Neutral lipid:chlorophyll, neutral lipid:particulate carbon (PC) and neutral lipid:particulate nitrogen (PN) ratios were highest in communities dominated by Nitzschia spp. and Navicula glaciei van Heurck. The lowest specific neutral lipid content was estimated in the congelation ice samples dominated by the diatom Amphiprora spp., and in surface assemblages dominated by Phaeocystis pouchetii Hariot and the dinoflagellate Gymnodinium sp. Scatter plots of neutral lipid on PC and PN, which included data from all assemblages, showed that assemblages dominated by P. pouchetii and Amphiprora spp. clustered near the origin reflecting their relatively lower specific neutral lipid levels, compared with assemblages dominated by N. glaciei and Nitzschia spp. Cellular PC:PN was significantly (P<0.001) lower in microalgae inhabiting surface melt pools or tide cracks compared to those associated with congelation or platelet ice.

Snow accumulation and surface microrelief distributions, together with the surface katabatic wind pattern and elevation profiles, are presented for the eastern Wilkes Land katabatic wind zone. The broad-scale net accumulation distribution displays a strong negative correlation with elevation but on the mesoscale there are significant variations with respect to the elevation profile. The accumulation distribution was found to be dependent on slope aspect. Higher accumulation rates were observed on the north-east (windward) slope than those on the north-west (leeward) slope for the elevation range of 1870 m–2230 m. These higher accumulation rates are associated with the occurrence of longitudinal dunes deposited by precipitation, during synoptic events. The dependence of the accumulation distribution on aspect implies that synoptic and orographic processes are the major control on the depositional regime, and that maritime synoptic systems regularly penetrate eastern Wilkes Land to at least 2300 m elevation.

The regional geology and lithostratigraphy of the Late Cretaceous strata of north-east James Ross Island have been described by a number of authors (e.g. Olivero et al. 1986, Pirrie 1989). The aim of this short note is to describe a sequence of strata currently assigned to the Santa Marta Formation, and to reinterpret the processes and environments of deposition of this sequence.

Major rifts is the Ross Ice Shelf controlled the October 1987 calving of the 154 × 35 km “B-9” iceberg, one of the longest on record. The 2000 km, 22 month drift of this iceberg and the quite different tracks of smaller bergs that calved with it have extended our understanding of the ocean circulation in the Ross Sea. B-9 initially moved north-west for seven months until deflected southward by a subsurface current which caused it to collide with the ice shelf in August 1988. It then completed a 100 km-radius gyre on the east-central shelf before resuming its north-westerly drift. Based upon weekly locations, derived from NOAA-10 and DMSP satellite and more frequent ARGOS data buoy positions, B-9 moved at an average speed of 2.4 km day−1 over the continental shelf. It was not grounded there at any time, but cast a large shadow of open water or reduced ice thickness during the austral winters. B-9 was captured by the continental slope current in May 1989, and attained a maximum velocity of 13 km day−1 before breaking into three pieces north of Cape Adare in early August 1989.

A new fossil genus of decapod Crustacea, belonging to the family Polychelidae is described from James Ross Island, Antarctic Peninsula. The specimen was obtained from a block of reworked Jurassic tuffaceous black shale belonging to the Ameghino (= Nordenskjöld) Formation in the Lower Cretaceous Kotick Point Formation. This is the first report of fossil Polychelidae in the Southern Hemisphere.

The youngest pre-caldera volcanism of Deception Island is represented by a thick sequence of subaerial pyroclastic deposits which has been grouped as the Yellow Tuff Formation. Most of these deposits were related to the explosive activity of a central vent which was destroyed during the formation of the caldera. Two members can be distinguished in this formation. The lower member is mainly composed of 1 to 12 m thick massive pyroclastic flow deposits with interbedded air-fall and surge deposits. The upper member is in stratigraphical continuity with the lower member and consists of base surge deposits with minor air-fall and thin pyroclastic flow deposits. The pre-caldera deposits have undergone a palagonitic alteration which produced crystallization of smectites, Fe-oxides, zeolites and calcite.

The direction and velocity of iceberg drift were measured during 1987 by photogrammetric methods. Drift along the southern coast of King George Island followed the NE and ENE directions of wind and water currents. The highest mean velocities (0.6–0.8 ms−1) were recorded in March and April, and the lowest velocities (0.1–0.2 ms−1) in winter, from May–July. From August–October velocities (0.4–0.6 ms−1) were higher than in November to December (0.4–0.5 ms−1). The waters flowing into Admiralty Bay came from the western part of the Bransfield Strait.

A new fauna of late Early to early Middle Triassic vertebrates has been found in the upper member of the Fremouw Formation in the Beardmore Glacier area of Antarctica. It includes Cynognathus, a kannmeyeriid, and other therapsid (mammal-like) reptiles representing new, more derived genera of carnivorous and gomphodont cynodonts. New genera of temnospondyl amphibians belonging to the capitosauroid evolutionary complex also occur. The unusual abundance of well-preserved amphibians may offer new insights concerning the evolution and distribution patterns of early Mesozoic temnospondyls. These fossils represent only the second terrestrial vertebrate fauna from the mainland of Antarctica. The fossils occur on a prominent sandstone platform, which represents part of the exhumed channel of a braided stream deposit. The platform is over 200 metres above the well-known Lystrosaurus fauna of the lower Fremouw Formation. The locality is near the axis of a major foreland basin that paralleled the present trend of the Transantarctic Mountains. Conditions of rapid subsidence and aggradation of fluvial units were ideal for the preservation of vertebrate faunas.

An analysis is made of the climate of the Australian Antarctic station Mawson (67.6°S, 62.9°E) and its hinterland in the light of 30 years of observations and of previous investigations. Data are presented on free atmosphere temperature and wind structure, the synoptic meteorology of the region, solar radiation, surface temperature, sea ice, wind and weather. Emphasis is placed on the characteristics of the shallow south easterly katabatic winds averaging 11.1 m s−1 throughout the year and the frequent periods of intense gale associated with the effects of major Southern Ocean depressions. The climate of Mawson is believed to be typical of much of the coast of East Antarctica in regions where the ice-cap falls steeply to sea level.

Marie Byrd Land is amongst the most inaccessible and least visited regions of Antarctica. It contains a large alkaline volcanic province, with 18 large central volcanoes and numerous small satellitic centres, ranging in age from late Oligocene (c. 28–30 Ma) to Recent (LeMasurier 1990). The volcanic rocks provide an outstanding record of the late Cenozoic glacial and volcanic history of Antarctica. The volcanism has been described within a region-wide model of hot-spot impingent at the base of the crust, widespread eruption of mafic plateau lavas and the sequential release of more evolved magmas from crustal chambers beneath central volcanoes situated along a series of reactivated, orthogonal basement fractures (LeMasurier & Rex 1989). Most of the volcanoes have been studied only on a reconnaissance level.

Ozone concentrations in the atmospheric surface layer above the Weddell Sea during the Antarctic spring season of 1989 varied significantly. Lower levels of ozone were associated with colder Antarctic air masses and higher values with warmer mid-latitude air. The lowest ozone concentration (1 to 2 ppbv) was measured in the centre of a low pressure system. A definite diurnal variation of tropospheric ozone observed during clear days with low total ozone amount (177 matm cm) may be interpreted as a consequence of the occurrence of photochemical reactions under conditions of increased ultraviolet solar radiation.

Unmanned magnetometer stations (UMS) have been developed and were installed at remote location near Syowa station, Antarctica (69°S, 40°E) to perform field tests in the harsh Antarctic environment. The UMS was powered by a thermo-electric generator fuelled by kerosene (LTEG) which supplies 87 Watts continuously to the load. The LTEG and instrumentation (flux gate magnetometer, data logger, chronometer) were installed in a thermally insulated shelter (0.9 m by 1.8 m by 1.9 m). The shelter and an 800 l fuel tank were mounted on a sled, and were towed by snow tractor. The UMS were installed at Kizahasi beach, Skarvsnes (50 km south-west of Syowa) and at H-100 of the Mizuho route (100 km south of Syowa) in the early spring of 1988 and operated until the end of the year. The data obtained will be used for a study of the spatial phase and amplitude structure of the ionospheric current systems and a response of the local induction currents to them.

The Shackleton Range occupies a key geological position in Antarctica (Fig. 1). Its location, at the edge of the continental craton between the mobile belts of the Transantarctic Mountains (TAM) and the stable platform of Dronning Maud Land (Neuschwabenland), and its geological constitution offer possibilities for: understanding the nature of the ‘Pacific’ margin of the Antarctic craton during the Palaeozoic, distinguishing between subduction- and collision-related tectonics at an ancient continental margin, and contributing to the debate on the relationship between East and West Antarctica. The structural orientation of the range, at right angles to the trend of the TAM, has puzzled geologists ever since its discovery.