(Table 1) Ice thickness of new subglacial lakes identified in the ICECAP RES data and of previously known subglacial lakes

Subglacial hydrology in East Antarctica is poorly understood, yet may be critical to the manner in which ice flows. Data from a new regional airborne geophysical survey (ICECAP) have transformed our understanding of the topography and glaciology associated with the 287,000 km**2 Aurora Subglacial Basin in East Antarctica. Using these data, in conjunction with numerical ice sheet modeling, we present a suite of analyses that demonstrate the potential of the 1000 km-long basin as a route for subglacial water drainage from the ice sheet interior to the ice sheet margin. We present results from our analysis of basal topography, bed roughness and radar power reflectance and from our modeling of ice sheet flow and basal ice temperatures. Although no clear-cut subglacial lakes are found within the Aurora Basin itself, dozens of lake-like reflectors are observed that, in conjunction with other results reported here, support the hypothesis that the basin acts as a pathway allowing discharge from subglacial lakes near the Dome C ice divide to reach the coast via the Totten Glacier.

Observation of manganese coating and encrustation in different environments of the North-Western Atlantic ocean

The major topographic features, or provinces, beyond the continental slope off the Atlantic coast of the United States are (1) Sohm Plain, (2) Hatteras Plain, (3) Nares Plain, (4) Blake Basin, (5) Blake Plateau-Bahama Banks, and (6) Bermuda Rise. The whole of the described area is commonly referred to as the North American Basin. This basin is bounded on the north by Newfoundland Ridge and on the south by Puerto Rico Trench. Topographic features of note within the basin are the divide and the area of depressions between Sohm and Hatteras Plains, the sharply crested Blake Ridge, and the Puerto Rico Ridge. Recently accumulated data on deep-sea oores has given good evidence that the silt and sand covering the abyssal plains are displaced continental sediments in a virtually quartz-free oceanic environment. These sediments were deposited on a primary volcanic bottom. The primary or volcanic bottom is characterized by abyssal hills and seamounts, and the sediment bottom is characterized by abyssal plains, which extend seaward from the continental margins. On the Blake Plateau, bottom photographs and dredge hauls in the axis of the stream show that locally sediment has been removed and the bottom is paved with crusts and nodules of manganese. Photographs and dredged samples from the outer part of the New England Seamount, Chain and Caryn Peak also indicate extensive encrustations of manganese oxide which acts as a binding agent in areas of ooze or other organic debris and thus helps to stabilize the bottom.

Major and trace element analyses of ODP Leg 120 volcanic rocks (Table 1)

Widespread Lower Cretaceous magmatism occurred along the Indian-Australian/Antarctic margins, and in the juvenile Indian Ocean, during the rifting of eastern Gondwana. The formation of this magmatic province probably began around 120-130 Ma with the eruption of basalts on the Naturaliste Plateau and at Bunbury, western Australia. On the northeast margin of India, activity began around 117 Ma with the Rajmahal continental basalts and associated lamprophyre intrusions. The formation of the Kerguelen Plateau in the Indian Ocean began no later than 114 Ma. Ultramafic lamprophyres (alnoites) were emplaced in the Prince Charles Mountains near the Antarctic continental margin at ~ 110 Ma. These events are considered to be related to a major mantle plume, the remnant of which is situated beneath the region of Kerguelen and Heard islands at the present day. Geochemical data are presented for each of these volcanic suites and are indicative of complex interactions between asthenosphere-derived magmas and the continental lithosphere. Kerguelen Plateau basalts have Sr and Nd isotopic compositions lying outside the field for Indian Ocean mid-ocean ridge basalts (MORB) but, with the exception of Site 738 at the southern end of the plateau, within the range of more recent hotspot basalts from Kerguelen and Heard Islands. However, a number of the plateau tholeiites are characterized by lower 206Pb/204Pb ratios than are basalts from Kerguelen Island, and many also have anomalously high La/Nb ratios. These features suggest that the source of the Kerguelen Plateau basalts suffered contamination by components derived from the Gondwana continental lithosphere. An extreme expression of this lithospheric signature is shown by a tholeiite from Site 738, suggesting that the southernmost part of the Kerguelen Plateau may be underlain by continental crust. The Rajmahal tholeiites mostly fall into two distinct geochemical groups. Some Group I tholeiites have Sr and Nd isotopic compositions and incompatible element abundances, similar to Kerguelen Plateau tholeiites from Sites 749 and 750, indicating that the Kerguelen-Heard mantle plume may have directly furnished Rajmahal volcanism. However, their elevated 207Pb/204Pb ratios indicate that these magmas did not totally escape contamination by continental lithosphere. In contrast to the Group I tholeiites, significant contamination is suggested for Group II Rajmahal tholeiites, on the basis of incompatible element abundances and isotopic compositions. The Naturaliste Plateau and the Bunbury Basalt samples show varying degrees of enrichment in incompatible elements over normal MORB. The Naturaliste Plateau samples (and Bunbury Basalt) have high La/Nb ratios, a feature not inconsistent with the notion that the plateau may consist of stretched continental lithosphere, near the ocean-continent divide.

Glaciological characteristics and carbon dioxide record of ice cores from Antarctica

We report a decadally resolved record of atmospheric CO2 concentration for the last 1000 years, obtained from the West Antarctic Ice Sheet (WAIS) Divide shallow ice core. The most prominent feature of the pre-industrial period is a rapid ~7 ppm decrease of CO2 in a span of ~20-50 years at ~1600 A.D. This observation confirms the timing of an abrupt atmospheric CO2 decrease of ~10 ppm observed for that time period in the Law Dome ice core CO2 records, but the true magnitude of the decrease remains unclear. Atmospheric CO2 variations over the time period 1000-1800 A.D. are statistically correlated with northern hemispheric climate and tropical Indo-Pacific sea surface temperature. However, the exact relationship between CO2 and climate remains elusive due to regional climate variations and/or uneven geographical data density of paleoclimate records. We observe small differences of 0 ~2% (0 ~ 6 ppm) among the high-precision CO2 records from the Law Dome, EPICA Dronning Maud Land and WAIS Divide Antarctic ice cores. However, those records share common trends of CO2 change on centennial to multicentennial time scales, and clearly show that atmospheric CO2 has been increasing above preindustrial levels since ~1850 A.D.

Benthos fauna in the North Sea from 2 surveys in 1986 and 1987

During two surveys in the North Sea, in summer 1986 and in winter 1987, larger epibenthos was collected with a 2 m beam trawl. The distributions of the species were checked for average linkage by means of the JACCARD-index cluster analysis. In summer two main clusters can be recognized. These are situated to the north and to the south of the Dogger Bank. In winter two main clusters may be recognized as well, but these clusters divide the North Sea into a western and an eastern part. We conclude, that these differences of epibenthos characteristics are correlated with seasonal changes in water body distributions.

(Table 1) Two-way travel times and depths of picked internal reflection horizons (IRHs) of the NGRIP ice core

During the summer of 2003, a ground-penetrating radar survey around the North Greenland Icecore Project (NorthGRIP) deep ice-core drilling site (75°06' N, 42°20' W; 2957 m a.s.l.) was carried out using a shielded 250 MHz radar system. The drill site is located on an ice divide, roughly 300 km north-northwest of the summit of the Greenland ice sheet. More than 430 km of profiles were measured, covering a 10 km by 10 km area, with a grid centered on the drilling location, and eight profiles extending beyond this grid. Seven internal horizons within the upper 120 m of the ice sheet were continuously tracked, containing the last 400 years of accumulation history. Based on the age-depth and density-depth distribution of the deep core, the internal layers have been dated and the regional and temporal distribution of accumulation rate in the vicinity of NorthGRIP has been derived. The distribution of accumulation shows a relatively smoothly increasing trend from east to west from 145 kg/m**2/a to 200 kg/m**2/a over a distance of 50 km across the ice divide. The general trend is overlain by small-scale variations on the order of 2.5 kg/m**2/a/km, i.e. around 1.5% of the accumulation mean. The temporal variations of the seven periods defined by the seven tracked isochrones are on the order of +-4% of the mean of the last 400 years, i.e. at NorthGRIP ±7 kg/m**2/a. If the regional accumulation pattern has been stable for the last several thousand years during the Holocene, and ice flow has been comparable to today, advective effects along the particle trajectory upstream of NorthGRIP do not have a significant effect on the interpretation of climatically induced changes in accumulation rates derived from the deep ice core over the last 10 kyr.

Static GPS measurements and elevation model in the vicinity of the EDML deep-drilling site

Interpretation of ice-core records requires accurate knowledge of the past and present surface topography and stress-strain fields. The European Project for Ice Coring in Antarctica (EPICA) drilling site (0.0684° E and 75.0025° S, 2891.7 m) in Dronning Maud Land, Antarctica, is located in the immediate vicinity of a transient and splitting ice divide. A digital elevation model is determined from the combination of kinematic GPS measurements with the GLAS12 data sets from the ICESat satellite. Based on a network of stakes, surveyed with static GPS, the velocity field around the EDML drilling site is calculated. The annual mean velocity magnitude of 12 survey points amounts to 0.74 m/a. Flow directions mainly vary according to their distance from the ice divide. Surface strain rates are determined from a pentagon-shaped stake network with one center point, close to the drilling site. The strain field is characterised by along flow compression, lateral dilatation, and vertical layer thinning.

Table 5 Comparison of surface elevations by Seasat and optical survey along EGIG line

Surface elevation maps of the southern half of the Greenland subcontinent are produced from radar altimeter data acquired by the Seasat satellite. A summary of the processing procedure and examples of return waveform data are given. The elevation data are used to generate a regular grid which is then computer contoured to provide an elevation contour map. Ancillary maps show the statistical quality of the elevation data and various characteristics of the surface. The elevation map is used to define ice flow directions and delineate the major drainage basins. Regular maps of the Jakobshavns Glacier drainage basin and the ice divide in the vicinity of Crete Station are presented. Altimeter derived elevations are compared with elevations measured both by satellite geoceivers and optical surveying.

Texture description and distribution of components in ODP Hole 103-639D (Figure 2)

A detailed analysis of the texture, matrix, and elements of the microfacies from the carbonate sequence recovered in ODP Hole 639D resulted in a typological classification of 10 major microfacies types and their variants. The variations in distribution and succession of type microfacies allowed us to divide the carbonate sequence into 12 facies-defined subunits. Based on the analyzed characteristics and their relations, we also propose a paleoenvironmental interpretation involving a mixed carbonate/terrigenous ramp model instead of the previous, classical zoned carbonate platform.

Accumulation rate and stable oxygen isotope ratios of the ice cores from the North Greenland Traverse

We present for the first time all 12 d18O records obtained from ice cores drilled in the framework of the North Greenland Traverse (NGT) between 1993 and 1995 in northern Greenland. The cores cover an area of 680 km × 317 km, 10 % of the Greenland ice sheet. Depending on core length (100-175 m) and accumulation rate (90-200 kg/m**2/a) the single records reflect an isotope-temperature history over the last 500-1100 years. Lowest d18O mean values occur north of the summit and east of the main divide as a consequence of Greenland's topography. In general, ice cores drilled on the main ice divide show different results than those drilled east of the main ice divide that might be influenced by secondary regional moisture sources. A stack of all NGT records and the NGRIP record is presented with improved signal-to-noise ratio. Compared to single records, this stack represents the mean d18O signal for northern Greenland that is interpreted as proxy for temperature. Our northern Greenland d18O stack indicates distinctly enriched d18O values during medieval times, about AD 1420 ± 20 and from AD 1870 onwards. The period between AD 1420 and AD 1850 has depleted d18O values compared to the average for the entire millennium and represents the Little Ice Age. The d18O values of the 20th century are comparable to the medieval period but are lower than that about AD 1420.

(Table 1) Ice floe size and other characteristics during aerial observations in Prydz Bay, Antarctica

On the basis of aerial photographs of sea ice floes in the marginal ice zone (MIZ) of Prydz Bay acquired from December 2004 to February 2005 during the 21st Chinese National Antarctic Research Expedition, image processing techniques are employed to extract some geometric parameters of floes from two merged transects covering the whole MIZ. Variations of these parameters with the distance into the MIZ are then obtained. Different parameters of floe size, namely area, perimeter, and mean caliper diameter (MCD), follow three similar stages of increasing, flat and increasing again, with distance from the open ocean. Floe shape parameters (roundness and the ratio of perimeter to MCD), however, have less significant variations than that of floe size. Then, to modify the deviation of the cumulative floe size distribution from the ideal power law, an upper truncated power-law function and a Weibull function are used, and four calculated parameters of the above functions are found to be important descriptors of the evolution of floe size distribution in the MIZ. Among them, Lr of the upper truncated power-law function indicates the upper limit of floe size and roughly equals the maximum floe size in each square sample area. L0 in the Weibull distribution shows an increasing proportion of larger floes in squares farther from the open ocean and roughly equals the mean floe size. D in the upper truncated power-law function is closely associated with the degree of confinement during ice breakup. Its decrease with the distance into MIZ indicates the weakening of confinement conditions on floes owing to wave attenuation. The gamma of the Weibull distribution characterizes the degree of homogeneity in a data set. It also decreases with distance into MIZ, implying that floe size distributes increase in range. Finally, a statistical test on floe size is performed to divide the whole MIZ into three distinct zones made up of floes of quite different characteristics. This zonal structure of floe size also agrees well with the trends of floe shape and floe size distribution, and is believed to be a straightforward result of wave-ice interaction in the MIZ.

Global hydrobelts and hydroregions

Hydrobelts divide the global landmasses into eight hydrological regions with resolution of 0.5°, based primarily on the annual average temperature (T) and runoff (q). The interbelt differences were maximised and intrabelt variability minimise. These hydrobelts are decomposed on continents as 26 hydroregions. The main aim of the dataset is to provide a robust reporting scale that could be used in water-related issues. The spatial datafiles for both, hydrobelts and hydroregions, are provided as shp-files and ascii raster files with accompanied metadata.