Apparent correlation of palaeomagnetic intensity and climatic records in deep-sea sediments

Most reports of a correlation between Pleistocene climate and geomagnetic field intensity rely strongly on the assumption that sediment natural remanent magnetic (NRM) intensity provides a record of geomagnetic field strength and is not sensitive to local changes in properties of the sediment. Critical assessment of relevant data presented here and elsewhere from deep-sea sediment cores shows that a pronounced dependence of NRM intensity on sediment composition can occur which implies that this assumption is unlikely to be generally valid. As sediment composition often reflects varying depositional conditions induced by climatic change, the significance of correlations proposed between Pleistocene palaeomagnetism and climatic indicators in deep-sea sediments may be less dramatic than sometimes supposed

Constraints on Cosmic Neutrino Fluxes from the ANITA Experiment

We report new limits on cosmic neutrino fluxes from the test flight of the Antarctic Impulsive Transient Antenna (ANITA) experiment, which completed an 18.4 day flight of a prototype long-duration balloon payload, called ANITA-lite, in early 2004. We search for impulsive events that could be associated with ultra-high energy neutrino interactions in the ice, and derive limits that constrain several models for ultra-high energy neutrino fluxes. We rule out the long-standing Z-burst model as the source for the ultra-high energy cosmic rays.Comment: 4 pages, 3 figures, accepted to PR

Subglacial and Seabed Topography, Ice Thickness and Water Columm Thickness in the Vicinity of Filchner-Ronne-Schelfseis, Antarctica

The seabed morphology beneath the ice shelf is dominated by a slope down towards the interior of the continent. Deep troughs, possibly glacially deepened, run beneath the eastern and weatern sides of the ice shelf and cross the continental shelf. An area of small water column thickness to the north-west of Berkner Island suggests that extensive grounding could occur after a relatively small change in the ice shel

Flow lines on Antarctic ice shelves

Satellite images of Ronne and Filchner ice shelves show a variety of surface features many of which are believed to indicate flow lines in the ice. Sufficient imagery is now available from Landsat satellites to plot these features from mosaics. Although some of the features have been recognized from aircraft, it was not until an overall view was provided that the true extent of the features and their relationship to the major ice streams became apparent. Using this evidence together with published ice thickness data from radio echo and seismic sounding, flow patterns within the ice shelves and tributary glaciers can be inferred

Investigations of an 'ice plain' in the mouth of Pine Island Glacier, Antarctica

We present newly acquired airborne radar data showing ice thickness and surface elevation for Pine Island Glacier, Antarctica. These data, when combined with earlier measurements, suggest the presence of a lightly grounded area immediately above the grounding line of Pine Island Glacier. We identify this region as a "ice plain". It lies close to the centre line of the glacier, has an elevation above buoyancy of 28 km. The upstream edge of the ice plain is defined by a "coupling line". The configuration of the ice plain implies that nearby thinning of the ice stream would result in substantial grounding-line retreat. We suggest that the grounding-line retreat of Pine Island Glacier, observed between 1992 and 1996, probably commenced sometime after 1981