The paper presents two years of observations (1995 and 1996) for water velocity and temperature near the Ross Ice Shelf edge, where a mooring, composed of three current meters, five temperature and three conductivity sensors, one turbidimeter, two sediment traps and one Acoustic Doppler Current Profiler, was deployed. The mooring site was chosen to study the behaviour of the Ice Shelf Water, within the framework of the Project on the Climatic Long-term Interaction for the Mass balance in Antarctica of the Italian National Programme for Antarctic Research. The Ice Shelf Water outflow from below the Ross Ice Shelf is a persistent phenomenon in this area, but it is characterized by impulsive injections often associated with recirculation processes. Two years of data records of physical variables are investigated here in order to analyse the Ice Shelf Water outflow behaviour and to give an estimate of this feature. Our results show that the Ice Shelf Water events have variable duration (from one to seven days) and present an interannual variability in their timing. In spite of this, the mean Ice Shelf Water outflow during the overlapping period of the two time series is quite similar: 0.15 Sv for 1995 and 0.28 Sv for 1996.

Six ichnocoenoses in the clastic Devonian Horlick Formation (max. 56 m) confirm the nearshore marine character of eight of the nine lithofacies present. Abasal sand sheet overlies a weathered granitic land surface (Kukri Erosion Surface) on Cambro–Ordovician granitoids. The level nature of this surface and the way it cuts across weathering profiles, suggests that the surface had been modified by marine processes prior to deposition. The basal sand sheet (Cross-bedded Sand sheet Lithofacies) contains tidal bundles, and at its top, abundant Monocraterion (Monocraterion Ichnocoenosis). The second sand sheet (Pleurothyrella Lithofacies) is heavily burrowed and shows alternating periods of sedimentation, burrowing, and erosion below wave base as the sea deepened (Catenarichnus Ichnocoenosis). With increasing transgression, finer sediments were deposited (Laminated Mudstone and Feldspathic lithofacies) in an unstable pattern of coarse sandbars and finer troughs (Cruziana-Rusophycus and Arenicolites ichnocoenoses) crossed by active longshore marine channels (Poorly-sorted Lithofacies, Spirophyton Ichnoocoenosis). Short-lived but powerful storms produced thin shelly tempestites (Shell-bed Lithofacies), whereas sporadic, very thin phosphate rich beds (Phosphatic Lithofacies) may have resulted from marine transgressions across the basin. The deepest water is probably represented by sediments of the Spirifer Lithofacies (Rosselia Ichnocoenosis). The Schulthess Lithofacies is regarded as fluvial, deposited in the lower reaches of a river draining a land area that lay towards Marie Byrd Land. Channels in the basal sand sheet indicate movement to the southwest, but orientation became more variable higher in the sequence. Four new measured sections are figured. The relationship of the Ohio Range to the rest of Antarctica during the Devonian is suggested.

Data from a monostatic acoustic radar operating at British Antarctic Survey's Halley station on a coastal Antarctic ice shelf show a band of small target echoes at an altitude of 700–1000 m during spring 1991. Statistical analysis of the echo signature show that the targets are spread more evenly in the horizontal than would be expected for a random signature, whilst the local distribution in the vertical is Gaussian. Similar echo signatures have been observed previously, and are attributed to birds, bats or insects: the Antarctic data are also consistent with bird targets, but the case is not proven. No birds have been observed directly, but at 700 m they would be barely visible to the naked eye. The nearest nesting area with suitably large numbers of birds (Antarctic petrels, Thalassoica antarctica) is a few hundred kilometres away. Estimates of velocity and target density imply that the Halley site would need to be specially favoured by the colony for their acoustic signature to be observed in such numbers, but such might be the case due to the presence of perennial coastal open water to the west of the station.

Bransfield Strait, a narrow active rift with three submarine basins, separates the South Shetland Islands from northern Antarctic Peninsula. Volcanism in Bransfield Strait commenced prior to 0.75 Ma and continues, with recent subaerial eruptions at Deception, Bridgeman and Penguin islands, submarine hydrothermal activity and numerous young basaltic seamounts located along the rift axis. Gravity cores were collected from five locations within the central Bransfield basin. Diatomaceous mud interbedded with terrigenous detritus and discrete ash layers up to 10 cm thick are the commonest sediment types in all the cores. The major element compositions of glass shards within the ash layers are, apart from the uppermost layer, compositionally similar to pyroclastic units preserved on Deception Island, a young (<0.75 Ma) active stratovolcano. The uppermost ash layer cannot be closely matched compositionally to any known source in the Antarctic–Scotia Sea–southern South America region. Its presence indicates that a volcanic centre other than Deception Island contributed ash to the Bransfield basin. Based on the shallow stratigraphical position of the compositionally distinctive ash layer, only a few decimetres beneath the seafloor, its source volcano was probably active in historical times (<few hundred years).

This paper addresses the study of the thermohaline circulation and convective processes induced by the presence of a coastal polynya in Terra Nova Bay (Ross Sea, Antarctica). These processes are analysed by means of oceanographic observations and numerical simulations. Time series of hydrological parameters and currents show the High Salinity Shelf Water (HSSW) formation with the mixing of the water column down to great depths, and a seasonal cycle of kinetic energy. A two-dimensional time dependent model for the numerical simulation of the effects of polynya on the circulation has been implemented. This model allows estimation of the contribution of thermohaline forcing on the circulation pattern, the amount of ice production consistent with the observed salinity distribution and annual cycle of currents and the amount of HSSW exported. The thermohaline forcing due to the polynya is able to induce strong horizontal currents up to 40 cm s−1 near the polynya area, as well as vertical movements of the order of 1 cm s−1. An annual ice production, ranging from 45 m to 90 m, mixes the water column at great depths, up to 750 m, and increases the salinity of the surface incoming waters up to 34.82. The estimated net north-eastward transport of HSSW ranges from 0.34 Sv to 1.23 Sv, depending on ice production.

The Horlick Formation is a fossiliferous, predominantly marine succession of interbedded sandstone and mudstone that crops out along a prominent escarpment in the Ohio Range. The formation buries a relatively level wave-cut platform eroded across a basement granitoid, and is nowhere more than 56 m thick due to subsequent Permo–Carboniferous glacial erosion.

The sediments have been described in terms of nine lithofacies (Bradshaw & McCartan 1983, McCartan & Bradshaw 1987), that were renamed in conjunction with the establishment of six ichnocoenoses (Bradshaw et al. 2002). An abundant but relatively limited shelly fauna was described by Doumani et al. 1965 and Bradshaw & McCartan 1991.

The six ichnocoenoses within the Horlick Formation have been used in palaeoenvironmental interpretations (Bradshaw et al. 2002). Catenarichnus is an important element and name bearer for one of these ichnocoenoses. Detailed descriptions of the remaining ichnofauna will be described in a separate paper.

Energy from the outer regions of the magnetosphere may be transferred to the polar ionosphere by plasma waves. A magnetometer array operated during the Antarctic winter observed Ultra-Low-Frequency (ULF) plasma waves in the Pc 1–2 (0.1–10.0 Hz) frequency range, propagating parallel to the surface of the Earth in a waveguide or duct centred at ∼300 km altitude in the ionosphere. These compressional fast mode plasma waves most likely originated in the outer magnetosphere as shear mode plasma waves guided along the geomagnetic field. The region of origin in the magnetosphere for the waves is not certain as several widely spaced volumes map along geomagnetic field lines to a relatively close ensemble in the polar ionosphere. This paper compares the direction of propagation for the waves with signatures of magnetospheric regions geomagnetically projecting onto the ionosphere. Regions such as the polar cusp, low latitude boundary layer and mantle were observed by DMSP spacecraft and a SuperDARN high-frequency radar. The most likely region in the polar ionosphere for the fast mode waves to have originated from is equatorwards of the polar cusp, suggesting the field guided waves originated just inside the magnetopause. A case is made for association of the observed Pc1-2 ULF waves with post-noon, field-aligned-current systems driven by reconnection of the solar Interplanetary Magnetic Field (IMF) and the geomagnetic field near the magnetopause.

The Darwin Glacier region is located between the Carlyon and Darwin glaciers in southern Victoria Land, Antarctica (Fig. 1). Previous work on Ross Orogeny granitoids of the Darwin Glacier region is mutually conflicting. Haskell et al. (1965) mapped three plutons, the Carlyon Granodiorite, Mount Rich Granite and Hope Granite, Felder & Faure (1990) did not recognise the Hope Granite, and Encarnación & Grunow (1996) interpreted the entire area as underlain by a single intrusion, the Brown Hills pluton. Fieldwork during the 2000 field season and subsequent geochemical and geochronological analysis described here indicates the presence of three distinctive granitic suites, emplaced during Cambrian times. These include the Foggy Dog Granite (FDG) suite, the Darwin calcic suite and the Cooper Granodiorite.