The geomagnetic field pattern in the vicinity of Georg Forster station, Antarctica, is discussed. Induced magnetization is assumed to model the regional minimum in the total field intensity (MAGSAT) located here, and an associated anomalous body at a depth of 50 km is calculated and interpreted. This model is, however, discounted in favour of a cross section derived from a meridional ground magnetic profile recorded over a distance of about 200 km. The most striking features of the profile are positive anomalies over the ice shelf which are explained by dykes of basic rocks emanating from the lower crust and from the mantle. The derived crustal structure reflects a transition from continental crust to transitional type crust.

This article is devoted to the assessment of trends of atmospheric air pollution and atmospheric impacts on the environment in the oases of the Thala Hills, Enderby Land, East Antarctica. Estimates of annual emissions of SO2, nitrogen oxides (NOx), inhalable particulate matter with a diameter of ≤ 10 μm (PM10) and CO and their dynamics over 56 years of Thala Hills exploration are given, as well as levels of surface air concentrations of SO2, NOx, PM10 and PM10 atmospheric depositions using air dispersion modelling. It is shown, in particular, that average annual emissions of NOx, PM10 and CO peaked in the early 1990s and have decreased 30.9 times by now. Sulphur dioxide emissions were highest in the late 1960s–late 1970s and decreased 270 times since then. Results of comparisons of modelled air concentrations and depositions with the available data on the measurement of surface air pollutant concentrations and atmospheric depositions are presented. Sources of uncertainties in the estimates of emissions, ground-level concentrations and depositions are described. Proposed approaches can be used to assess the cumulative impacts of ongoing and planned activities on atmospheric air and on other components of the environment through assessing the atmospheric air in the Antarctic Treaty area.

Throughout the Transantarctic Mountains, Early Jurassic silicic magmatism preceding the emplacement of the Ferrar flood-basalt province (Heimann et al. 1994) is documented by the increasing input of silicic ash into otherwise epiclastic, fluviolacustrine deposits of the Beacon Supergroup (see Elliot et al. 2017). Vertebrate biostratigraphy and radiometric analyses indicate a Sinemurian to Pliensbachian age span for silicic volcaniclastic deposits in the central Transantarctic Mountains (CTMs) (Elliot et al. 2017). For northern Victoria Land (NVL), radiometric geochronology and palynostratigraphy revealed that explosive silicic volcanism began with minor pulses during the early Sinemurian (c. 195 Ma) and reached a peak phase beginning in the middle Pliensbachian (c. 187 Ma) (Bomfleur et al. 2014). A basin-wide correlation of these widely separated age frameworks has so far been hampered by the scarcity of data on coeval deposits in southern Victoria Land (SVL). Here, we present new palynostratigraphic data from mixed epiclastic–volcaniclastic deposits in the Prince Albert Mountains that provide supporting evidence for the widespread synchronicity of silicic volcanic episodes preceding Ferrar magmatism.

Chinstrap penguins (Pygoscelis antarcticus) show little sexual dimorphism and sexing by direct observation can be difficult. Through molecular techniques, male and female adults were identified at Stinker Point, Elephant Island, South Shetland Islands, in the 2011–12 and 2012–13 breeding seasons. In the assessment of sexual dimorphism using morphological characteristics, males were 6.0–9.4% larger than females. From the most significant morphological measurements, a discriminant function was formulated that classified 80.6% of the birds correctly. In addition, our data on bill length and depth were compared with those in the literature to evaluate sexual dimorphism between different breeding locations and to test the performance of the discriminant function. There were no differences in sexual dimorphism between breeding locations. However, the discriminant function should be used with caution because some penguins may be misclassified. Therefore, when there is doubt about the accuracy of morphometric approaches, application of molecular sexing techniques is recommended.

Scanning electron microscope and image analysis techniques were used to construct a profile of otolith growth from June 1987–June 1988 in immature Notothenia coriiceps. Growth was found to fluctuate seasonally with a large decrease between August and late November 1987. Examination of stomach fullness showed that fish continued to feed during winter. Increases in absolute light levels and sea temperature during spring were found to coincide approximately with increasing growth. Conclusive evidence distinguishing between hypotheses for limitation of growth either by seawater temperature or by resource availability was not found.

Microwave radiometer SSM/I (Special Sensor Microwave Imager) data and scatterometer QuikSCAT (Quick Scatterometer) data have been widely used for near-surface snow melt detection based on their sensitivity to liquid water present in snow. The SSM/I data have high reliability and the QuikSCAT data have high spatial resolution. In order to improve the accuracy of Antarctic near-surface snow melt detection, we propose a new method based on the synergy of SSM/I and QuikSCAT data, i.e. the snow melt physical model incorporates the complementary advantages of both datasets. Based on comparisons with temperature data from three automatic weather stations, the proposed algorithm improved the accuracy of snow melt detection. The algorithm could also be applied to other regions, which would provide further evidence to support its use and additional data to document changes in the Antarctic due to global climate change.

Antarctic research has progressed steadily from the era of reconnaissance studies into a period of problem-oriented scientific investigation. The International Geophysical Year and the intensive work of the 1960s and 1970s have established fundamental knowledge of Antarctic environmental systems on which present and future activities can be planned. Antarctic scientists of all nationalities are now eager to accept and exploit the challenges presented by global change programmes. At its XXth meeting in Hobart in September 1988, SCAR proposed an Antarctic component for inclusion in the ICSU International Geosphere–Biosphere Programme. Antarctic science thus considers itself sufficiently mature to be able to contribute effectively to programmes of world scope. Indeed, involvement in such activities may be seen as mandatory in order to continue to underscore the credibility and mainstream relevance of Antarctic scientific endeavours.

Cetacean fossils have been recorded from middle and late Eocene deposits on Seymour Island since the beginning of the twentieth century and include fully aquatic Basilosauridae and stem Neoceti. Here, we report a small cetacean vertebra tentatively referred to as Neoceti from the late Eocene of Seymour Island. It shows a mosaic of traits, some of which are characteristic of early Neoceti (anteroposteriorly long transverse processes; a ventral keel on the ventral side of the centrum; thin pedicles of the neural arch), whereas others are shared with Basilosauridae (low-placed bases of the transverse processes). However, some traits are unique and may be autapomorphic: presence of separate prezygapophyses on the vertebra at the thoracic/lumbar boundary and a proportionally short centrum. Both traits imply a fast swimming style, which is characteristic of modern dolphins rather than Eocene cetaceans. Thus, this specimen can be identified as Neoceti indet., with some hypothetical odontocete affinities. Along with a few other Eocene whale taxa, it seems to be among the earliest known members of Neoceti on Earth. The finding of small and fast-swimming Neoceti in Antarctica also demonstrates early diversification of cetaceans and ecological niche partitioning by them dating back as early as the late Eocene.

The first recorded volcanic eruption in Antarctica occurred on Bridgeman Island (South Shetland Islands) in early 1821, < 2 years after Antarctica was discovered. However, the observations were disputed owing to a lack of physical evidence. A consensus arose that they probably referred to Penguin Island, a young volcano with a well-formed volcanic cone situated just 60 km to the west. However, a recent re-examination of the historical reports demonstrated that the event was undoubtedly located at Bridgeman Island. Our new study demonstrates that the eruption was explosive and lasted throughout 1821. The vent was situated in the sea ~500 m to the west of Bridgeman Island and the eruption was hydrovolcanic (Surtseyan). The new volcano constructed a tuff ring composed of unconsolidated lapilli and ash, which rapidly coalesced with nearby Bridgeman Island, similar to how the Capelinhos volcano joined with neighbouring Faial (Azores) in 1957–1958. The tuff ring had a very low profile and was rapidly removed by marine erosion. However, fumarolic activity persisted for a few decades. Because the eruption is only 200 years old, the underlying volcanic construct (Bridgeman Rise) should be regarded as dormant rather than extinct.

Here we describe new microfossil assemblages for the Miocene Hobbs Glacier Formation and the first possibly indigenous assemblages for the Plio-Pleistocene Weddell Sea Formation on Seymour Island, West Antarctica. The assemblages are composed mainly of foraminifers, but radiolarians, calcitarchs and poriferan sclerites are also present. For the Hobbs Glacier Formation, we report the foraminifers Bolivina sp., Oolina globosa and Rosalina cf. globularis; and for the Weddell Sea Formation, we report Favulina hexagona, Globigerinita uvula, Globocassidulina cf. subglobosa and Psammosphaera fusca. The low abundance and diversity of microfossils, allied with the complex taphonomical processes that prevailed in Antarctic glacial–marine palaeoenvironments, make it impossible to define whether the assemblages are composed of a mixture of indigenous and re-elaborated specimens or exclusively of re-elaborated remains. Nevertheless, the indigenous nature of some specimens is suggested by their inherent fragility, excellent preservation and/or taxonomic association with indigenous assemblages from correlated strata. The taxonomic compositions are not directly comparable with other Antarctic assemblages, although most of the species were previously reported from pre-Quaternary or modern deposits of both West and East Antarctica. This lack of correspondence is probably due to preservation biases, but any further significance is hidden by the complex taphonomy of the deposits.

The changes implemented in 2005 in the development strategies of Antarctic science carried out by Chile have had a positive impact on the scientific productivity of the Chilean Antarctic Science Program (PROCIEN). We analysed scientometric indicators from between 2009 and 2019. The bibliographic data were extracted from the Web of Science database using search query keywords. We used multiple correspondence analysis to identify specific trends and also network analyses of international collaboration in VOSviewer. The number of Antarctic science publications in Chile has gradually increased from 21 in 2009 to 95 in 2019. The rise in the number of articles was higher in journals for the first impact factor quartile. Research lines showing increased first-quartile impact factor papers corresponded to Antarctic ecosystems, biotechnology and geosciences. The main geographical domains in which such research activities have been carried out corresponded to in the South Shetland Islands and the Antarctic Peninsula. Fieldwork data are the main sources for the production of scientific articles, and there are three science platforms within which most of these papers concentrate. The diversification of funding sources, the implementation of improvements in the selection process and Chile's alignment with Scientific Committee on Antarctic Research programmes have contributed to improving the science that Chile has developed in Antarctica.

Details are presented of seismic velocities at a site near Rothera Point, Adelaide Island, Antarctic Peninsula. The snow/firn velocity structure was obtained using a 24-channel Bison 9000 seismograph, recording the outputs of geophones of 40 Hz natural frequency attached to 150 mm snow spikes. The refraction velocity of the underlying bedrock was measured using a 48-channel DFS V recorder and 10 Hz geophones. The records were obtained during trials of equipment and techniques which took place in the 1988–89 and 1990–91 seasons. The data will be of interest to other investigators studying firn structure around Antarctica or considering crustal seismology in the Antarctic Peninsula region.

The distribution of annual mean biomass of mesozooplankton (animals in the size range 0.2–20 mm) in the upper layer (0–100 m) of the Atlantic sector of the Southern Ocean was mapped. The map was constructed from 4216 measurements at 2184 oceanographic stations, from the Russian and Brazilian archive records, from published sources, and from the British Oceanographic Data Centre. The annual mean mesozooplankton biomass value for the South Atlantic is estimated in this study to be 93 mg m−3 wet weight.