The Permian ended with the largest of known mass extinctions in the history of life. This signal event has been difficult to recognize in Antarctic non-marine rocks, because the boundary with the Triassic is defined by marine fossils at a stratotype section in China. Late Permian leaves (Glossopteris) and roots Vertebraria), and Early Triassic leaves (Dicroidium) and vertebrates (Lystrosaurus) roughly constrain the Permian–Triassic boundary in Antarctica. Here we locate the boundary in Antarctica more precisely using carbon isotope chemostratigraphy and total organic carbon analyses in six measured sections from Allan Hills, Shapeless Mountain, Mount Crean, Portal Mountain, Coalsack Bluff and Graphite Peak. Palaeosols and root traces also are useful for recognizing the Permian–Triassic boundary because there was a complete turnover in terrestrial ecosystems and their soils. A distinctive kind of palaeosol with berthierine nodules, the Dolores pedotype, is restricted to Early Triassic rocks. Late Permian and Middle Triassic root traces are carbonaceous, whereas those of the Early Triassic are replaced by claystone or silica. Antarctic Permian–Triassic sequences are among the most complete known, judging from the fine structure and correlation of carbon isotope anomalies.

On innumerable occasions, Adélie (Pygoscelis adeliae) and emperor penguins (Aptenodytes forsteri) have been observed in close proximity to killer whales (Orcinus orca), with no whale-penguin interactions reported. On the other hand, killer whales reportedly harass and eat seabirds on occasion (Walker 1968: p. 1122, Stacey et al. 1990, Williams et al. 1990). Killer whales are known to prey on young king penguins (A. patagonica) as they are fledging (Guinet 1992, Guinet & Bouvier 1995) and occasionally take emperor penguins (Mikhalev et al. 1981). Thomas et al. (1981) report killer whales chasing Adélies. Here we report the only observations of Adélie-killer whale interactions observed in nine field seasons on Ross Island.

On the basis of observations of Weddell seals (Leptonychotes weddellii Lesson) made in the course of studying shallow-water benthic communities in McMurdo Sound, Antarctica, we suggest that caching and/or defence of uneaten food may be a strategy practiced by this animal. Such a phenomenon is uncommon but taxonomically widespread among vertebrates. Depending on circumstances, it is termed hoarding, caching, or storage and may be short- or long-term, include defence of the resource, or have other variable expressions, with the common threads being deferred consumption and deterrence of consumption by others (Vanderwall 1990). Many vertebrate taxa exhibit hoarding behaviour, including rodents (e.g. Sciuridae), carnivores (e.g. Canidae, Felinidae) and birds (e.g. Corvidae, Picidae). No form of food caching, to our knowledge, has ever been reported in a wild pinniped.

A low diversity plant macrofossil assemblage described from the northern section of Fossilryggen, Vestfjella, Dronning Maud Land, Antarctica, is dominated by matted leaf impressions of Glossopteris sp. cf. G. communis Feistmantel and Glossopteris sp. cf. G. spatulata Pant & Singh, and in situ finely branched Vertebraria indica Royle rootlets. Equisetalean stems, rhizomes and leaf whorls (Phyllotheca australis Brongniart emend. Townrow), isolated seeds, scale-leaves, and fragmentary gymnosperm axes represent minor components of the assemblage. The fossils are preserved in fine-grained, floodbasin sediments and dark palaeosols. Although lacking definitive biostratigraphical indices, the flora is considered to represent a Middle Permian assemblage based principally on lithological and palynological correlation with the southern section at Fossilryggen and broad similarities to mid-Permian plant assemblages elsewhere in Gondwana.

The McDonald Islands (53°S, 73°E) originally comprised three small islands that lie on the Kerguelen Plateau, 44 km west of Heard Island. No volcanic activity was observed since their discovery in 1874 until 1997, when two passing ships recorded major changes and eruptive behaviour. A 2001 satellite image showed that the main island had doubled its area. This paper reports observations made from a cruise ship in November 2002, supplemented by a high-resolution satellite image acquired in March 2003. A new volcanic complex comprises lava domes, spines and flows, all assumed to be phonolitic, similar to the older volcanic rocks. The complex shows dormant volcanic activity, with numerous fumaroles, recent spine evolution and lava flows. Changes in relative sea level have connected Flat and McDonald Islands. A spit about 1km long with extensive shoals beyond, now extends eastward from McDonald Island and presents new hazards to shipping. Biological changes include colonization by king penguins (Aptenodytes patagonica), previously absent, and a large reduction in numbers of formerly widespread macaroni penguins (Eudyptes chrysolophus chrysolophus).

Phyllolepid placoderm remains from the Aztec Siltstone fish fauna are described as Austrophyllolepis quiltyi sp. nov., Austrophyllolepis cf. A. youngi, Placolepis tingeyi sp. nov., and phyllolepid indet. The new Antarctic species of two genera previously only known from Australia reinforce evidence from other fish taxa of close biogeographic affinity, as part of the eastern margin of Palaeozoic Gondwana. At least three genera and four species gives the Aztec Siltstone fish fauna the most diverse phyllolepid assemblage known, and probably the oldest documented so far (?late Middle Devonian). Specimens of Austrophyllolepis from the type locality at Mount Howitt, Victoria, are refigured for comparison with the Antarctic species. The order Phyllolepida is a key group for understanding Devonian vertebrate biogeography and palaeogeography, with a unique disjunct distribution in both time and space between the Southern and Northern hemispheres. Phyllolepids document one of the major dispersal events in early vertebrate history, which approximately coincided with the Frasnian–Famennian boundary mass extinction during the Late Devonian.

To date, Cretaceous nautilids from the Antarctic Peninsula have received little attention and only a single species had been reported, Eutrephoceras simile Spath, from Seymour, Snow Hill, and James Ross islands. Currently, it is considered a synonym of Eutrephoceras subplicatum (Steinmann), which has also been described from the Upper Cretaceous of central Chile, southern Argentina and Angola. Here, we report and describe E. subplicatum in detail, based on specimens from the Lower Campanian–Maastrichtian of Vega, Seymour and James Ross islands, presenting, for the first time, embryonic conch features related to the palaeoecology of these organisms. The nauta of this species had a diameter of approximately 30 mm with 5–6 septa. In addition, we describe a new species, Eutrephoceras antarcticum, and one specimen assigned to the same genus in open nomenclature, both recovered from the Lower Campanian beds of James Ross Island.

A revised stratigraphy of Cenozoic volcanic outcrops in the Brandy Bay area on James Ross Island is obtained by combining palaeomagnetic and stratigraphical anlysis with 40Ar/39Ar dating. The fieldwork was carried out between January and March 2002. Oriented palaeomagnetic samples were obtained from 17 volcanic units, the majority of samples being from lava-fed deltas. Individually the deltas are a few to several hundred metres thick and were formed during voluminous basaltic eruptions within an ice sheet or in a marine setting. Out of the sampled units, 15 carry a stable primary magnetization; six were of normal polarity and nine were reversely magnetized. Our 40Ar/39Ar dating constrains the emplacement of most of the Brandy Bay basalts to the Gilbert chron, with the youngest dated unit having an age of 3.95 Ma and the oldest 6.16 Ma. The mean palaeomagnetic field direction from 14 units has an inclination I = −76° and declination D = 352°, α95 = 7°. The results further suggest that the lava caps on some of the deltas have high remanent intensity and should generate recognizable aeromagnetic anomalies. The combination of palaeomagnetic and isotopic analysis with field mapping methods in a single field area is unique in Antarctica so far and demonstrates that the combination can yield rigorous local stratigraphy in a geographically remote volcanic terrain having discontinuous outcrops.

The palynological content of randomly collected sedimentary rock clasts from the till on the south-east slope of the Basen nunatak in northern Vestfjella in western Dronning Maud Land indicate that these sedimentary rocks were derived from strata of Middle Permian age. The palynological content and preservation is similar to palynofloras described from the sedimentary rocks that crop out at the Fossilryggen nunatak to the south-east, therefore, it seems likely that the Fossilryggen area represents the source of the sedimentary rock samples in the Basen till. This is further supported by known ice flow directions obtained from striations and clast fabric measurements in the area.

Deception Island (South Shetlands, Antarctica) is one of the most active volcanoes in Antarctica, having erupted recently in 1967, 1969 and 1970, damaging scientific stations on the island. It is also seismically very active. The island has attracted the attention of many researchers as it constitutes an undisturbed natural laboratory to study seismo-volcanic events and how they affect landscape modelling and evolution. One of the most remarkable geological and geomorphological features on Deception Island is the linearity of its easternmost coastal landform, the origin of which remains unknown. Some answers, based on presence of strike-slip fault or on the ice cap and beach geomorphological dynamics, have been reported in the literature. Our new work provides several indications of the existence of a dip-slip submarine fault, parallel to the coast (NNW–SSE), which suggests a tectonic origin for this morphological feature. Uplifted marine terraces, incision of a fluvial network over the ice cap, normal faulting parallel to the coast in the north and south rock heads bounding the beach and sharp shelf-break with rather constant slope, constitute some of this evidence. Terrace uplift and fluvial channel incision decreasing southward from Macaroni Point, indicates possible tilt movement across this inferred fault plane.

The Bruce, Discovery, Herdman and Jane banks, all located along the central-eastern part of the South Scotia Ridge, represent isolated topographic highs, surrounded by young oceanic crust (∼5–23 Ma), whose petrological and structural nature is still the subject of speculation due to the lack of relevant data. Surface wave tomography in and around the Scotia Sea region, performed using eight broadband seismic stations and 300 events, shows that the central-eastern part of the South Scotia Ridge is characterized by negative surface wave group velocity anomalies as large as 6% in the period range from 15 s to 50 s. The spatial resolution of our data set (∼300 km) makes it possible to study a specific area (centred at 61°S and 36°W) that includes Discovery Bank and appears to show dispersion characteristics similar to those found beneath the northern tip of the Antarctic Peninsula and southern South America. Surface wave dispersion curves are inverted to obtain 1-D isotropic shear wave velocity profiles that suggest a continental nature of Discovery Bank. Crustal thickness is in the range 23–28 km with a sub-Moho velocity of 4.1–4.2 km s−1. The boundaries of the negative group velocity anomalies are marked by a high level of seismic activity. The depth of the events and their large seismic moment suggest the presence of continental lithosphere. The continental-type crust of this topographic relief is supported by our interpretation of multichannel seismic reflection profiles acquired across this rise, where the observed seismic structures are interpreted as thinned and faulted continental plateau.

Fluctuations in the volume of the Antarctic ice sheet for the last 740 ka are calculated by forcing a simple ice sheet model with a sea-level history (from a composite deep sea δ18O record) and a temperature history (from the Dome C deuterium record). Antarctic ice volume reaches maximum values of about 30 × 1015 m3, 3 to 8 ka after glacial maxima [defined as maximum values of the deep sea δ18O record]. Minimum values of ice volume reached in the course of interglacial periods are about 26 × 1015 m3. Most of the time the temperature forcing (larger accumulation) and sea-level forcing (grounding-line retreat) tend to have competing effects. However, towards the end of a glacial cycle, when temperature rises and sea-level is still relatively low, the ice volume reaches a peak. The peak value is very sensitive to the relative phase of the sea-level forcing with respect to the temperature forcing. This is further studied by looking at the response of the model to purely periodic forcings with different relative phase. The large sensitivity of ice sheet size to the phase of the forcings may have some implications for dating of deep ice cores. Care has to be taken by using anchor points from the deep sea record.

Well sorted, fine lithic sandstone within the Drygalski Formation at Cape Lockyer on the southern tip of Heard Island, preserves a diverse terrestrial palynoflora as well as marine diatoms and a few foraminifera. A combination of these elements suggests a Late Miocene age (10–5 Ma). The palaeovegetation was markedly different from that presently on the island, and appears to comprise at least two ecologically distinct communities: open heath or herbfield dominated by grasses and Asteraceae, and a more mesophytic community dominated by ferns but also including lycopods and angiosperms such as Gunnera. This may have represented a coastal flora similar to the ‘fern-bush’ community that exists now on Southern Ocean islands north of the Antarctic Polar Frontal Zone, and in Tierra del Fuego; however, there is no evidence of tree species in the local flora and trace amounts of tree pollen present may have blown in from other landmasses in the region.

In an attempt to clarify the release of trace elements from the seasonal coastal sea ice, samples were periodically collected in a nearshore station inside the Gerlache Inlet (Terra Nova Bay, Western Ross Sea), during the summer 2000/01 and analysed for dissolved and particulate cadmium, copper, iron, manganese and lead, as well as salinity, suspended particulate matter, nutrients and phytoplankton pigments. In order to provide insight on the metal association with the particles included in the sea ice, the metal solid speciation was also investigated. Both vertical distributions within the ice cores and temporal variations at the seawater interface were studied, in an effort to fully characterize the system and correlation among the considered parameters. Concentrations and speciation patterns clearly indicate metal incorporation within the annual sea ice due to resuspension of sediments, followed by release of particulate metals during melting as a primary process affecting trace metal availability in the Antarctic coastal waters.

The barotropic and baroclinic tides in the Ross Sea were simulated using a primitive equation, sigma-coordinate model, the Regional Ocean Model System (ROMS), for four tidal constituents, M2, S2, K1, and O1. Small elevation amplitudes were predicted over most of the basin, with a combined standard deviation of 30–50 cm. Larger amplitudes, with standard deviations ranging from 50–70 cm, occurred deep within the ice shelf cavity, over the continental slope, and over Iselin Bank. Most of the elevation response was associated with the diurnal constituents (K1 and O1), as was most of the depth-independent (barotropic) velocity response. Baroclinic tides were generated at locations of steep topography for the semidiurnal constituents, but not the diurnal. Diurnal continental shelf waves were generated by the diurnal tides and found to amplify the semidiurnal elevations and baroclinic tidal velocities over the continental slope. Comparisons with observations in both elevation and velocities showed very good agreement for the semidiurnal constituents (M2 and S2) and moderate agreement for the diurnal constituents (K1 and O1). The disagreement for the diurnal constituents was associated with diurnal frequency continental shelf waves, which were overexcited along the shelf break. The baroclinic tides induced both small-scale horizontal and vertical shear in the velocity fields in the Ross Sea.

Depleted mantle model ages derived from granitoids of the Lassiter Coast Intrusive Suite, sampled over a wide geographical area in eastern Ellsworth Land, Antarctica, cluster between 1000 Ma and 1200 Ma and suggest involvement of Proterozoic crust in the petrogenesis of the suite. Ion-microprobe U–Pb zircon analyses from a small intrusion at Mount Harry, situated at the English Coast, yield a concordant age of 105.2 ± 1.1 Ma, consistent with published ages from other parts of the Lassiter Coast Intrusive Suite. Significant variation in the Sr and Nd isotope composition of the granitoids, along the extrapolation of the Eastern Palmer Land Shear Zone (a proposed terrane boundary) located close to the English Coast, is not evident. However, the isotope signature at the English Coast is more homogeneous than the Lassiter Coast; this variation may relate to geographical proximity to the Pacific margin during intrusion, may reflect subtle changes in basement with a broadly similar character across the proposed terrane boundary, or suggest that any major fault structure is located further to the north, with implications for the kinematics of regional mid-Cretaceous transpression.

This paper focuses on the daily cycle of the surface energy balance and the atmospheric surface layer during a detailed meteorological experiment performed near Kohnen base in Dronning Maud Land, East Antarctica, in January and February 2002. Temperature, specific humidity, wind speed and the turbulent scales of these quantities, exhibit a strong daily cycle. The sensible heat flux cycle has a mean amplitude of ∼8 W m−2, while the latent heat flux has an amplitude of less than 2 W m−2, which is small compared to the amplitude of net radiation (∼ 35 W m−2) and sub-surface heat (∼ 25 W m−2). Between ∼ 9 and 16 h GMT convection occurs due to a slightly unstable atmospheric surface layer. At the end of the afternoon, the wind speed decreases abruptly and the mixed layer is no longer supported by the sensible heat input; the stratification becomes stable. At night a large near-surface wind shear is measured due to the presence of a nocturnal jet, which is likely to be katabatically driven, but can also be the result of an inertial oscillation. No strong daily cycle in wind direction is recorded, since both the katabatic forcing at night and the daytime forcing by the large-scale pressure gradient were directed approximately downslope during the period of measurement.