ALBERT

Description: ANTscape is a project of the Antarctic Climate Evolution (ACE) Research Program to develop a series of maps to show changes in Antarctic paleotopography over the last ~100 million years. The reconstructions will provide a base for summarising a range of paleoenvironmental data, and for use as inputs for the next generation of ice sheet-ice shelf models. The present-day bedrock topography from the SCAR BEDMAP project will be used as a starting point for reconstructing past paleotopography, moving to BEDMAP 2 when it becomes available. Six maps, one for each significant climatic regime or shift, are planned: 4, 14, 34, 50, 70 and 92 Ma. Work is well advanced on the map for 34 Ma (Wilson and Luyendyk, 2009, Geophysical Research Letters). This is a time that is far enough back for there to be a significantly different topography, but not so far back that reconstruction is seriously unconstrained. It is also of great interest to paleoclimatologists as the largely ice-free landscape on which the first continental ice-sheet formed. The maps prepared by ANTscape will depend not only on restoration of Antarctic continental geography by reversing tectonic movements and elevation changes, but also the restoration of sediment eroded from the continent and deposited around and beyond the Antarctic margin. This will require modeling changes to the Antarctic landscape from erosion (Jamieson et al., 2010, Earth & Planetary Science Letters) and estimates of sediment volumes through the Circum-Antarctic Stratigraphy and Paleobathymetry Project (CASP). For further information see www.ANTscape.aq

Description: ANTscape is an ACE project to develop over the next three years a series of maps to show the changes in Antarctic paleotopography over the last ~100 million years. The reconstructions will provide a base for summarising a range of paleoenvironmental data, and be useful both as inputs for the next generation of ice sheet-ice shelf models, and for credible and realistic visualization of past landscapes to promote wider appreciation of past changes in the Antarctic environment. The first meeting of the group in April 2009 in Leeds agreed that for younger periods (Cenozoic) the present-day bedrock topography from the SCAR BEDMAP project would be a useful starting point for reconstructing past paleotopography, moving to BEDMAP 2 when it became available. However for older periods researchers would have to draw more on current knowledge of plate movements, tectonic deformation, thermal evolution and personal geological experience. Because of the scarcity of geological data, it was recognised that the reconstructions would entail considerable geological interpretation. However it was acknowledged that even poorly constrained reconstructions would be a significant improvement on the current practice of using present day topography for models of past ice sheets, when we know past topography was different.The following six time slices, each representing a significant climatic regime or shift, were proposed for a map: 4, 14, 34, 50, 70 and 92 Ma, with work beginning first on a map for 34 Ma. This is a time that is far enough back for there to be a significantly different topography, but not so far back that reconstruction is seriously unconstrained. It is also of great interest to paleoclimatologists as the largely ice-free landscape on which the first continental ice-sheet formed. The group leader for this time slice is Doug Wilson. The group decided the maps could most conveniently be developed by considering the Antarctic as comprising three large regions: 1) West Antarctica: Marie Byrd Land, Antarctic Peninsula, Ellsworth Mountains, West Antarctic rift system, Weddell Sea and Ross Sea, 2) East Antarctica including Transantarctic Mountains, and 3) the Antarctic margin, comprising the continental shelf and slope as far as the continent- ocean transition. A number of procedural issues are under discussion by ANTscape members, and input is sought from ACE 2009 participants in order that the issues be resolved in 2009. These include the primary geospatial tools to be used, spatial resolution of the primary product, the organizational scheme for gridding the data, and data/document storage and access. For the moment a report on the Leeds workshop along with abstracts and many of the presentations given there can be found at http://groups.google.com/group/antscape?hl=en The maps prepared by ANTscape will depend not only restoration of Antarctic continental geography by reversing tectonic movements and elevation changes, but also the restoration of sediment eroded from the continent and deposited around and beyond the Antarctic margin. This will require close collaboration with ROSSmap and the Circum-Antarctic Stratigraphy and Paleobaythmetry Project (CASP).

Description: The James Ross Basin, at the northern tip of the Antarctic Peninsula, provides the thickest and best-exposed onshore Cretaceous and Early Tertiary sedimentary succession in Antarctica. When compared with other onshore sections, it is clear that the area has a much broader significance as a key reference section for the Cretaceous and Early Tertiary throughout the Southern Hemisphere. The sedimentary record exposed within the basin also provides an unrivalled opportunity to unlock the record of climate change and biotic response within a high-palaeolatitude setting. James Ross Island was first visited during the heroic age of polar exploration at the start of the 20th century. Swedish geologist Otto Nordenskjold sailed into the region in 1901 in his ship Antarctic, captained by explorer and sealer Carl Larsen. Plans to spend a year in the region for scientific exploration went disastrously wrong when his ship sank near Paulet Island, forcing Nordenskjold to spend over 2 years in a small hut on Snow Hill Island. Members of his ship-wrecked party survived in horrific conditions, with only penguins for food and small stone huts for shelter at Hope Bay, at the tip of Trinity Peninsula, and also on Paulet Island. Nordenskjold's enforced stay in the area was, however, not unprofitable. In 1902 he and his five companions made trips over the sea ice to Seymour Island, where they made the first important fossil discoveries, including the bones of giant penguins (now known to be from the Eocene La Meseta Formation). This was well before Scott's ... This 250-word extract was created in the absence of an abstract.

Description: Small chorate dinoflagellate cysts are common in Upper Cretaceous to Quaternary sedimentary successions around the Antarctic margin. Taxonomic confusion surrounding dinoflagellate cysts and acritarchs of similar morphology throughout the southern high palaeolatitudes has hitherto limited investigation of their palaeoecological significance. This study aims to solve the taxonomic problems, and to allow a new assessment of dinoflagellate cyst acmes. A detailed morphological study of new material from the López de Bertodano Formation of Seymour Island, Antarctic Peninsula, is presented. These dinoflagellate cysts are identified as Impletosphaeridium clavus Wrenn & Hart 1988 emend. nov. Their gross morphology and their vast abundances in the James Ross Basin are strongly suggestive of dinoflagellate blooms. This scenario implies similarities to modern dinoflagellate cysts from the polar regions.