Lichenometry on adelaide island, antarctic peninsula: size‐frequency studies, growth rates and snowpatches

Abstract For many types of seaweeds in Polar Regions, open questions remain about how their life cycle contributes to their overall adaptation to the extreme abiotic environment. This applies in particular to the major canopy-forming brown algae in much of the Antarctic Peninsula of the genus Desmarestia, which was investigated here. Diving surveys around Rothera Research Station (Adelaide Island, Antarctica) during December 2017–February 2018 revealed the widespread presence of a hitherto-unknown life form of Desmarestia sp. of a tender, feather-like morphology. Further studies explored whether this could be (1) a new, hitherto undescribed Desmarestia species (2) a new record for the region of a known Desmarestia species previously recorded elsewhere or (3) a so-far unknown life form of a species recorded for the region. Collections enabled the extraction of PCR-friendly DNA and sequencing of ITS1, which unambiguously showed that the samples belonged to Desmarestia menziesii, the only Desmarestia species presently recorded for the Adelaide Island/Marguerite Bay region. The presence of the juvenile morphology was subsequently confirmed throughout much of the natural range of D. menziesii during cruise-based diving surveys along the Western Antarctic Peninsula in 2019 and from collections at Anvers Island in 1989. Our collections thus constitute its juvenile morphology, which is not previously documented in the literature. The wider significance for the Polar seaweeds is discussed in the context of Taxonomy and Ecology.

Download Full-text

Assessing the potential of multispectral remote sensing for lithological mapping on the Antarctic Peninsula: case study from eastern Adelaide Island, Graham Land

Antarctic Science ◽

10.1017/s0954102010000015 ◽

2010 ◽

Vol 22 (3) ◽

pp. 299-318 ◽

Cited By ~ 17

Author(s):

C.E. Haselwimmer ◽

T.R. Riley ◽

J.G. Liu

Keyword(s):

Remote Sensing ◽

Antarctic Peninsula ◽

Spectral Properties ◽

Volcanic Rocks ◽

Lithological Mapping ◽

Aster Data ◽

Intrusive Rocks ◽

Multispectral Remote Sensing ◽

The Antarctic ◽

Adelaide Island

AbstractThe results of lithological mapping using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data for the Wright Peninsula region of Adelaide Island, Antarctic Peninsula are compared with existing geological maps and recent field observations to assess the potential of multispectral remote sensing to undertake lithological mapping on the Antarctic Peninsula. The Wright Peninsula comprises calc-alkaline intrusive rocks ranging from granite to gabbro, volcanic rocks of acidic to intermediate composition, and arc-related sediments. The reflective and thermal bands of a single ASTER image were analysed with reference to reflectance spectra of rock samples from the study area. Assessment of the ASTER mapping outcomes was undertaken with a newly compiled geological map of Adelaide Island and observations made during recent fieldwork. The results demonstrate that ASTER can uniquely discriminate granitoid intrusive rocks and altered rhyolitic volcanic rocks that display distinctive spectral properties. The results are more ambiguous at discriminating more intermediate/mafic rocks such as diorite/gabbro, andesite/basalt and chlorite-bearing sediments due to the similarity in spectral properties. These results demonstrate that although ASTER data are limited in their ability to uniquely discriminate lithologies they can provide important lithological information in support of geological mapping on the Antarctic Peninsula.

Download Full-text

Cenozoic stress field in the southwestern Antarctic Peninsula from brittle mesostructures in Wright Peninsula, Adelaide Island

Polish Polar Research ◽

10.2478/v10183-011-0006-8 ◽

2011 ◽

Vol 32 (1) ◽

pp. 39-58 ◽

Cited By ~ 1

Author(s):

Adolfo Maestro ◽

Jerónimo López-Martínez

Keyword(s):

Stress Field ◽

Antarctic Peninsula ◽

Bimodal Distribution ◽

Horizontal Stress ◽

Early Miocene ◽

Western Antarctic Peninsula ◽

Compressional Stress ◽

Stress States ◽

Maximum Horizontal Stress ◽

Adelaide Island

Cenozoic stress field in the southwestern Antarctic Peninsula from brittle mesostructures in Wright Peninsula, Adelaide IslandPalaeostresses inferred from brittle mesostructures in the southern Wright Peninsula show a stress field characterized by compressional, strike-slip and extensional regime stress states. The compressional stress (σ1) shows a main NW-SE direction and the extensional stress (σ3) shows a relative scattering with two main modes: NE-SW to E-W and NW-SE. The maximum horizontal stress (σy) has a bimodal distribution with NW-SE and NE-SW direction. The compressional orientation is related to subduction of the former Phoenix Plate under the Antarctic Plate from the Early Jurassic to the Early Miocene. Extensional structures within a broad-scale compressional stress field can be related to both the decrease in relative stress magnitudes from active margins to intraplate regions and stretching processes occurring in eastern Adelaide Island, which develop a fore-arc or intra-arc basin from the Early Miocene. Stress states with NW-SE-trending σ1are compatible with the dominant pattern established for the western Antarctic Peninsula. NW-SE orientations of σ3suggest the occurrence of tectonic forces coming from fore-arc extension along the western Antarctic Peninsula.

Download Full-text

Chrono- and lithostratigraphy of a Mesozoic–Tertiary fore- to intra-arc basin: Adelaide Island, Antarctic Peninsula

Geological Magazine ◽

10.1017/s0016756811001002 ◽

2011 ◽

Vol 149 (5) ◽

pp. 768-782 ◽

Cited By ~ 10

Author(s):

TEAL R. RILEY ◽

MICHAEL J. FLOWERDEW ◽

MARTIN J. WHITEHOUSE

Keyword(s):

Antarctic Peninsula ◽

Basaltic Andesite ◽

West Coast ◽

Volcanic Rocks ◽

Volcanic Group ◽

Volcaniclastic Rocks ◽

Definition Of ◽

The Antarctic ◽

Adelaide Island

AbstractThe Mesozoic fore-arc of the Antarctic Peninsula is exposed along its west coast. On Adelaide Island, a 2–3 km succession of turbiditic coarse sandstones and volcanic rocks is exposed. Four U–Pb (zircon) ages are presented here that, in combination with a new stratigraphy, have permitted a robust chrono- and lithostratigraphy to be constructed, which in turn has allowed tentative correlations to be made with the Fossil Bluff Group of Alexander Island, where the ‘type’ fore-arc sequences are described. The lithostratigraphy of Adelaide Island includes the definition of five volcanic/sedimentary formations. The oldest formation is the Buchia Buttress Formation (149.5 ± 1.6 Ma) and is correlated with the Himalia Ridge Formation of Alexander Island. The sandstone–conglomerate dominated succession of the Milestone Bluff Formation (113.9 ± 1.2 Ma) is tentatively correlated with the Pluto Glacier Formation of Alexander Island. Three dominantly volcanic formations are recognized on Adelaide Island, akin to the volcanic rocks of the Alexander Island Volcanic Group; the Mount Liotard Formation is formed of 2 km of basaltic andesite lavas, whilst the Bond Nunatak Formation is also dominated by basaltic andesite lavas, but interbedded with volcaniclastic rocks. The Reptile Ridge Formation has been dated at 67.6 ± 0.7 Ma and is characterized by hydrothermally altered rhyolitic crystal-lithic tuffs. Tentative correlations between Adelaide Island and Alexander Island preclude the two areas forming part of distinct terranes as has been suggested previously, and a proximal source for volcaniclastic sediments also indicates an exotic terrane origin is unlikely.

Download Full-text

The management of sledge dogs in the Antarctic

Polar Record ◽

10.1017/s0032247400028680 ◽

1976 ◽

Vol 18 (112) ◽

pp. 25-35

Author(s):

R. W. Bostelmann

Keyword(s):

Antarctic Peninsula ◽

Scientific Work ◽

Field Work ◽

Summer Season ◽

Falkland Islands ◽

Main Form ◽

Areas Of Interest ◽

The Antarctic ◽

Adelaide Island ◽

Permanent Presence

The British Antarctic Survey (BAS) has relied on sledge dogs as the main form of transport for field parties since its predecessor, the Falkland Islands Dependencies Survey (FIDS), imported them in 1945, when it created a permanent presence on the continent. Over the years dogs have been used for extensive work over a very wide area. In 1975 BAS changed its policy with respect to work in the southern Antarctic Peninsula. In future seasons scientists will not winter in this area but will be flown to Adelaide Island and then into the field. They will carry out more detailed scientific work in particular areas of interest. This means that it is no longer practical to maintain huskies on base as they could not be kept fit and well disciplined during the winter for a short summer season. The scientists, similarly, could not be expected to learn to work the dogs efficiently in the time available, and the change in the nature of their work means that they will not move camp so frequently. The dogs, since they must be fed even if they are resting, would be uneconomic in such a situation. Finally, most of the work will be in areas that are thought to be safe so the dogs will not be needed to probe for crevasses. In future seasons BAS will rely on skidoos for field work (Figs 1 and 2).

Download Full-text