Chemial and isotope compositions of rocks from the West Antarctic

The paper is devoted to a marine geophysical-geological research in the West Antarctic. This researche contributed to establishing the base geodesic network of the West Antarctic and supplemented geokinematic monitoring based on this network with geophysical and geologic information on structure and features of geomorphological and tectonic development of the South Ocean floor. Collected materials allow to conclude about the inhomogeneity of the Scotia Sea floor and about combination of fragments of a continental massif with young rift structures in conditions of the upwelling mantle. The ancient continental bridge, faunal connections between the South America and the West Antarctic has been destroyed by processes of destruction, taphrogeny and sea floor spreading. Structures of the Scotia and Caribbean Seas, North Fiji and Arctic Basins are similar.

Lagrangian back-tracing results for Kohnen station; output of time dependent numerical experiment with a 3D nested Antarctic ice sheet model

A nested ice flow model was developed for eastern Dronning Maud Land to assist with the dating and interpretation of the EDML deep ice core. The model consists of a high-resolution higher-order ice dynamic flow model that was nested into a comprehensive 3-D thermomechanical model of the whole Antarctic ice sheet. As the drill site is on a flank position the calculations specifically take into account the effects of horizontal advection as deeper ice in the core originated from higher inland. First the regional velocity field and ice sheet geometry is obtained from a forward experiment over the last 8 glacial cycles. The result is subsequently employed in a Lagrangian backtracing algorithm to provide particle paths back to their time and place of deposition. The procedure directly yields the depth-age distribution, surface conditions at particle origin, and a suite of relevant parameters such as initial annual layer thickness. This paper discusses the method and the main results of the experiment, including the ice core chronology, the non-climatic corrections needed to extract the climatic part of the signal, and the thinning function. The focus is on the upper 89% of the ice core (appr. 170 kyears) as the dating below that is increasingly less robust owing to the unknown value of the geothermal heat flux. It is found that the temperature biases resulting from variations of surface elevation are up to half of the magnitude of the climatic changes themselves.

Antarctic dataset in NetCDF format

The dataset described in this document has been put together for the purposes of numerical ice sheet modelling of the Antarctic Ice Sheet (AIS), containing data on the ice sheet configuration (e.g. ice surface and ice thickness) and boundary conditions, such as the surface air temperature and accumulation. It is now possible to download a community ice sheet model (e.g. Glimmer-CISM, Rutt et al., 2009 doi:10.1029/2008JF001015), but without adequate data it is difficult to utilise such models. More specifically, ice sheet models that are initialised and run forward from the present day ice sheet configuration, need input data to represent the present-day ice sheet configuration as closely as possible (unlike those spun-up from ice free conditions, which only require the bed/bathymetry). Whilst the BEDMAP dataset (Lythe et al., 2001) was a step forward when it was made, there are a number of inconsistencies within the dataset (see Section 3), and since its release, more data has become available. The dataset described here incorporates some major new datasets (e.g. AGASEA/BBAS ice thickness, Nitsche et al. (2006) bathymetry doi:10.1029/2007GC001694), but by no means incorporates all the new data available. This considerable task is left for a 'BEDMAP2', (an updated version of BEDMAP), however, the processing carried out in this document illustrates the requirements of a dataset for the purpose of high resolution ice sheet modelling, and bridges the gap until a BEDMAP2 is published. It is envisaged, however, that updated versions of the data set will be made available periodically when new regional data sets become available and can be readily incorporated.