Results of the sorting of the mikronekton and zooplankton material sampled by the German Antarctic Expedition 1975/1976

A description is given of the taxa sorted out of the zooplanktion and mikronekton material of the 1st German Antarctic Expedition 1975/76 by the Kiel sorting center. The methods employed in the sorting center are describined in detail. Notes for further use of the material are also given.

Colored dissolved organic matter (cDOM) absorption measurements in Antarctic lakes

The datasets present measurements of cDOM absorption of lakes located in Antarctic oasis during the summer periods from 2013 to 2016. In summer season of 2013 water samples were collected on Fildes Peninsula (King George Island, West Antarctica) - Bellingshausen Station, Russia. Investigated lakes on Fides Peninsula were completely or partly free from ice cover during water sampling. In summer seasons of 2014-2016 water samples were collected on Vestfold Hills, Reuer Island and Larsemann Hills Oasis (East Antarctica) - Progress station, Russia. During 2014-2016 summer season part of lakes on Larsemann Hills Oasis were free from ice cover, some of the lakes were completely covered by ice and were drilled before sampling. Part of the water samples from Progress Station (2015) has not been filtered. cDOM is operationally defined by the chosen filter pore size. Samples have been consistently filtrated through 0.7 µm pore size glas fibre filters. cDOM filtrates have been stored in darkness and have been measured after the expedition using the dual-beam Specord200 laboratory spectrometer (Jena Analytik) at the Otto Schmidt Laboratory OSL, Arctic and Antarctic Research Institute, St. Petersburg, Russia. The OSL cDOM protocol (Heim and Roessler, 2016) prescribes 3 Absorbance (A) measurements per sample from UV to 750 nm against ultra-pure water. The absorption coefficient, a, is calculated by a = 2.303A/L, where L is the pathlength of the cuvette [m], and the factor 2.303 converts log10 to loge. The output of the calculation is a continuous spectrum of a. The cDOM a spectra are used to determine the exponential slope value for specific wavelength ranges, S by fitting the data between min and max wavelength to an exponential function. We provide cDOM absorption coefficients for the wavelengths 254, 260, 350, 375, 400, 412, 440, 443 nm [1/m] and Slope values for three different UV, VIS, wavelength ranges: 275 to 295 nm, 350 to 400 nm, 300 to 500 nm [1/nm]. All data were carried out by scientists from Arctic and Antarctic Research Institute and Saint Petersburg State University of Russia during Russian Antarctic Expedition in 2013-2016.

Sea ice physics from the southern Weddell Sea

During the German Antarctic Expedition 1979/80, the sea ice conditions in the Weddell Sea were studied along the ice shelf between Cape Fiske (root of the Antarctlc Peninsula) and Atka Bay. Most intensively was the sea ice investigated in an area about 100 km northwest of Berkner Island, where a suitable site for the German station was found. In addition to the drift conditions, ice thickness as weIl as temperature and salinity of the ice were measured and the mechanical properties established. Several ice cores were taken back to Germany, where the compressive strength was measured in respect to strain rate, salinity, depth and temperature.

Tab. 1: Results of the movement measurements on the blue ice-field Blåisen

In January/February 1985 a German-South African expedition had the opportunity to repeat measurements made by means of stakes planted in 1951 (Norwegian-British-Swedish Antarctic Expedition 1949-52) and 1966 (SANAE VII). Although the rediscovery of the old stakes had not been expected, the stakes could be identified and it was possible to derive movement vectors on the basis of old and heterogenic measurement data. The long-term movement rates established basically confirm and complement the values determined in 1951. The flow rates of 9,1 cm/a to 66.4 cm/a proved to be extremly low. Observations of the stake lengths showed very little accumulation in the fringe areas of the blue ice-field (ca. 0.7 to 2.6 cm/a snow/firn); on bare ice an ablation of 2.6 cm/a water equivalent (2.9 cm/a ice) was measured. The paper begins with a description of the essential conditions for the formation of the blue ice-field. Subsequently the measurements are explained in detail and their results are discussed.

Fig. 6: Firn temperatures at Filchner Station

During the German Antarctic Expedition 1979/80 to the Filchner/Ronne Ice Shelf glaciclogical investigations were carried out at the Filchner station, mainly for determination of snow accumulation. Also meteorological measurements and observations were part of the programme. Similar glaciological work on a smaller seale was done at Atka Ice Port. The report presents the results of the glaciological investigations, In an introductory part some basie eonsiderations, definitions and methods are discussed briefly, completed by a few hints on practical snow pit work. Density measurements, stratigraphie analyses with aid of a throughlight profile and hardness determination are described in more detail. The analyses of the Fi1chner snow profile of January 1980 with suplements of January 1981 reveal 7 complete budget years for 370 cm depth or 53 cm snow accumulation/year, With a mean density of 0.377 g/cm**2 this value corresponds to a water equivalent of 20 g/cm**2. At the Atka site 3 budget years were determined within 210 cm depth of the snow pit or 70 cm of mean annual accumulaticn. With the rat her higher mean density of 0.438 g/cm**2 for this site the corresponding water equivalent amounts here to 30 g/cm**2, In addition to the snow pit studies shallow drillings were made at Filchner Station to a depth of 10.8 m with 128 sampies taken from the core and at Atka to 12.1 m depth with 114 sampies. At the Institute for Radiohydrometry, Neuherberg, the sarnples were analysed with respect to the stable isotope ratios 2H/1H and 18O/16O related to V-SMOW. Also the tritium content was measured. The vartiations of the stable isotope ratios with the depth show quasiperiodic fluctuations which are regarded as annual cycles of the accumulation rate. Counting of the pronounced peaks leads to 20 years for the Filchner core, giving 55 cm annual accumulation or 22 g/cm**2 water equivalent respectively. At Atka 15 years could be found corresponding to 75 cm annual accumulation or 32 g/cm**2 of water. The range of varianon and the mean value of the stable isotope ratios are significantly different for both sites, the agreement of the isotopic anal yses with the pit studies is rat her satisfactory. The tritium content shows for the Filchner core two pronounced peaks which can be related to the 1965 and 1966 winter seasons according to former studies at the South Pole station. These time estimates are consistent with the time scale derived fr orn the stable isotopes distribution. At the Atka site no similar effeet in the tritium values was found. In the drill holes firn temperatures were measured carefully. The 10 m value was determined to be -25 °C at Filchner Station and -17 °C at the Atka position.

Geological map of northern XU-Fjella, Heimefrontfjella, Dronning Maud Land, Antarctica (Scale 1:25,000)

The geological map shows the northeastern part of the polyphase deformed Sivorg Terrane in the Heimefrontfjella/Dronning Maud Land. The basement was affected by late Mesoproterozoic and Cambrian deformation and metamorphism. Geological mapping was carried out during the Antarctic Expedition 2000/01 of the Alfred Wegener Institute for Polar and Marine Research. Topographic data were obtained through stereoscopic aerial photo interpretation. The photogrammetric photo flights were undertaken in 1986 by the Institut für Angewandte Geodäsie, Frankfurt/M. Horizontal ground control points required for aerial photo interpretation were determined by means of Doppler satellite observation during the 2nd German Neuschwabenland Expedition 1985/86. Vertical ground control points were taken from unpublished map drafts at 1:100 000 scale by Norsk Polarinstitutt, Oslo. The elevation above mean sea level was transferred to Heimefrontfjella barometrically. For this reason assertions concerning the absolute elevation (referred to sea level) are uncertain. Contours and spot heights presented on the map were obtained from the photogrammetric evaluation of the photography taken in 1986; relative elevation data (height differences) are accurate to approximately ±10 m. Published by Fachbereich Geowissenschaften, Universität Bremen & Geologisches Institut, RWTH Aachen.

Geological map of HANSSONHORNA, Heimefrontfjella, Dronning Maud Land, Antarctica, 2nd revised Edition (Scale 1:25,000)

The geological map shows the border area between the polyphase (late Mesoproterozoic and Cambrian) deformed Sivorg Terrane and the Kottas Terrane where a pervasive Cambrian tectonometamorphic overprints is lacking. Geological revision mapping was carried out during the Antarctic Expedition 2000/01 of the Alfred Wegener Institute for Polar and Marine Research. Topographic data were obtained through stereoscopic aerial photo interpretation. The photogrammetric photo flights were undertaken in 1986 by the Institut für Angewandte Geodäsie, Frankfurt. Horizontal ground control points required for aerial photo interpretation were determined by means of Doppler satellite observation during the 2nd German Neuschwabenland Expedition 1985/86. Vertical ground control points were taken from unpublished map drafts at 1:100 000 scale by Norsk Polarinstitutt, Oslo. The elevation above mean sea level was transferred to Heimefrontfjella barometrically. For this reason assertions concerning the absolute elevation (referred to sea level) are uncertain. Contours and spot heights presented on the map were obtained from the photogrammetric evaluation of the photography taken in 1986; relative elevation data (height differences) are accurate to approximately ±10 m. Published by Geologisches Institut der RWTH Aachen & Fachbereich Geowissenschaften, Bremen.

Radiocarbon dating on four sediment profiles from Bunger Hills, East Antarctica

Radiocarbon dating was carried out on the total organic carbon of 19 lacustrine and marine sediment samples from the Bunger Hills. The results indicate that radiocarbon contamination is negligible throughout two sediment sequences from a fresh water lake. In contrast, two sequences from marine basins are irregularly influenced by the Antarctic Marine Reservoir Effect, which today amounts to more than 1000 years, depending on the degree of dilution with meltwater. All sediments were deposited during Holocene time.

Geochemistry of selected Ferrar samples from Northern Victoria Land and George V Land during GANOVEX VIII

Newly sampled basaltic andesites and andesites from the tholeiitic Ferrar Supergroup of northern Victoria Land and George V Land, Antarctica, are attributed to the known low-Ti and high-Ti series. Aside from known sparsely distributed high-Ti extrusives, a high-Ti sill was found in the Alamein Range outside the Rennick Graben. Low-Ti lavas, sills and dikes display wide petrographical, mineral and geochemical variations, reflecting extensive in-situ differentiation. High-Ti rocks from Litell Rocks are homogeneous with respect to mineralogy and geochemistry, minor deviations are shown by the sampled sill. Chilled margins of low-Ti sills, dikes and lava flows exhibit nearly constant bulk-rock chemistry (mg# ~60) within the studied area. Compared to chilled margins from Tasmanian sills, the striking uniformity of the pre-emplacement chemistry of Ferrar magmas over large distances supports the magma transport model of Elliot et al. (1999, doi:10.1016/S0012-821X(99)00023-0). In the area investigated, compositional variations within the low-Ti series, caused by in-situ differentiation, increase towards the Wilson-Bowers Terrane boundary, possibly displaying the asymmetrical distribution of outcrops over this area. Absence of Ferrar occurrences east of the Bowers Terrane remains a matter of palaeo-geodynamic discussion. Besides, the secondary mineralogy of extrusives from Litell Rocks and Monument Nunataks exhibits noticeable differences, which indicates an elevated thermal gradient in the vicinity of Litell Rocks compared to Monument Nunataks during the Cretaceous.