John F. Splettstoesser

Antarctica: Geology of the Ellsworth Mountains.

Geologic reconnaissance indicates that the Ellsworth Mountains consist mainly of thousands of feet of folded, slightly metamorphosed, clastic sedimentary rocks of unknown age. Three major stratigraphic units are recognized, but only fragmentary fossils have been found. The folding is asymmetric, overturned, or recumbent; fold axes strike north, 10� to 20� west. Basic igneous sills occur in the northern Heritage Range.

Notes on Antarctic wildlife: Ross seals Ommatophoca rossii and emperor penguins Aptenodytes forsteri

Abstract Systematic observations on birds and mammals were carried out in the 1996/97 austral summer in Antarctica while on a circumnavigation of the entire continent by the Russian icebreaker Kapitan Khlebnikov. A total of 22 Ross seals Ommatophoca rossii were recorded during the period 9 December 1996–16 January 1997 of that 65 day cruise, with 75% of them found in light to heavy pack ice conditions. The highest abundance was in the Riiser‐Larsen Sea (between 14°E and 35°E longitude). Half of the seals were observed over the shelf zone, while others were over continental slope to deep ocean. Discussion of all sea‐ice habitats from all sightings of Ross seals from the 1996/97 summer is presented here, along with opportunistic sightings of Ross seals from the same icebreaker in December 1992‐January 1993 and in 1997/98 along the coastline from about 57°E to 100°E. An unusually large concentration of Ross seals was observed during an 8 h period near Gaussberg (66° 13′S, 89°35′E) on 7 January 1993, when a minimum of 40 Ross seals were counted. A search for an emperor penguin Aptenodytes forsteri colony was made in November ‐ December 1997 in the area of the West Ice Shelf, where a colony at Pingvin Island was discovered in 1956 and last seen in 1960. The original population of 30 000 birds was not found, but a smaller subcolony of about 200 breeding pairs (estimated) was found, perhaps a remnant of the original colony which was forced to re‐locate because of a major breakup of West Ice Shelf in 1968.

The first transit of the Northwest Passage by Russian icebreaker

In a voyage beginning 24 July in Ulsan, South Korea, and ending i n St Petersburg, Russia, on 21 September 1992, the icebreaker Kapitan Khlebnikov successfully completed an unassisted transit of the Northwest Passage, from Bering Strait to the North Atlantic Ocean. The ship was chartered jointly by Polar Schiffahrts-Consulting, Hamburg, Germany; Blyth and Company Travel, Toronto, Ontario, Canada; and D.G. Wells Marine Ltd, Ottawa, Ontario, Canada. It was marketed for tourists, some of whom traveled the entire distance of 14,120 nautical miles [26,150 km]. Khlebnikov was the fifty-third vessel to complete the Northwest Passage since Roald Amundsen first accomplished it in 1906 (Pullen and Swithinbank 1991, and confirmed by the office of Coast Guard Northern, Ottawa, Canada).

Antarctic Circle Crossed by Large Cruise Vessel

The first crossing of the Antarctic Circle by MS Amsterdam, a large cruise vessel with a passenger capacity of some 1,300, was made twice in the 2003-2004 austral summer on the western side of the Antarctic Peninsula. MS Amsterdam is the largest cruise vessel to cross the Antarctic Circle, and the second largest ship to do so, the first being the U.S. aircraft carrier Philippine Sea during Operation Highjump, 1946-1947. Sea-ice conditions in the area cruised were unusually light, with minor scattered icebergs. Advantages of multiple cruises using a non-ice-strengthened vessel in the same areas in an austral summer include determination of sea-ice distribution and weather patterns over several months, leading to better predictions for avoidance of areas with difficult ice conditions, thus saving valuable cruise time and fuel, in addition to a safety factor.

Columnar jointed sandstone in Beacon Supergroup, Britannia Range, Antarctica

Abstract A columnar jointed structure occurs in Hatherton Sandstone (Devonian) where it is intruded by Ferrar Dolerite (Early Jurassic) in the Britannia Range, Antarctica. Although Ferrar Dolerite sills and dikes intrude sedimentary rocks of the Beacon Supergroup over much of the Transantarctic Mountains, this is the first report of columnar jointed sandstone. Petrography of the jointed rock shows it to be a medium to fine grained, moderately well sorted quartzarenite composed of moderately well to well rounded grains of quartz and very minor amounts of potassium feldspar and quartzose rock fragments. A series of measurements of microjoints showed nearly random orientations.

The Greenland Ice Sheet Program: 1975 field activities

The Greenland Ice Sheet Program (GISP) in August 1975 completed its fourth successful field programme since its beginning in 1971. The GISP research is aimed at the investigation of glaciological, geophysical, geochemical and palaeo-climatological parameters of the Greenland ice sheet and at the interpretation of these factors in terms of climatic significance for the present and for the future.