摘要:

An extensive glaciological programme was started on the McMurdo Ice Shelf in the 1962–63 summer. Parameters such as absolute movement, direction of movement, compression and extension strain rates, 10-metre density profiles, and accumulation rate have been measured. Preliminary examination of the data show little direct relation between orientation of maximum compression and absolute speed of movement and direction.

ISSN:0028-8306    

DOI:10.1080/00288306.1967.10426751

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

Compared with the other continents Antarctica is remarkably free from earthquakes, especially in view of the active volcanism and other signs of instability. On the hypothesis that earthquake activity is affected by variations in the thickness of the ice-cap, any future earthquake of even moderate magnitude may be expected to yield useful information about the source mechanism of earthquakes and also about ice-cap dynamics.

ISSN:0028-8306    

DOI:10.1080/00288306.1967.10426752

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

In order to study the regimen of the McMurdo Ice Shelf three holes, 31, 32, and 57 m deep, were drilled near the seaward edge of the shelf; ice thicknesses at the drill sites were calculated to be 33, 48, and 94 m respectively. The rate of melting at the bottom of the shelf was found to be 1 m per year at two drill sites. The vertical density gradient in each of the holes is larger than that observed at Little America Station, and the density increases abruptly by about 0.1 g cm−3at the top of a brine-soaked layer which was estimated to be less than 6 m thick in each hole. Temperature profiles can be explained on the assumption that the brine moves horizontally through the shelf from the seaward edge to the interior and supplies heat to the shelf by convection and by liberation of latent heat during freezing. The observed brine level in the holes is about 20 percent lower than the hydrostatic level.

ISSN:0028-8306    

DOI:10.1080/00288306.1967.10426753

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

A map and descriptions of the soils of Taylor Dry Valley, Victoria Land, Antarctica, are presented. Soils from Hallett Station, Ross Island, and other places around McMurdo Sound are briefly described and compared with those of Taylor Dry Valley. The role of the soil-forming factors and the nature of the soil.forming processes in Victoria Land is discussed. Soils on “normal sites” (e.g., on slightly elevated gentle slopes on moraine or similar parent material) may be regarded as zonal soils. They are virtually lithochromic, coarse textured, structureless, and without humic horizons. Two groups are recognised: (a) Those in arid Taylor Dry Valley, which have a surface or subsurface layer slightly to moderately cemented with calcium carbonate or gypsum and are underlain at depths of about 12 in. by frozen ground. (b) Those outside Taylor Dry Valley, e.g., at Hallett Station and Ross Island and also at high elevations; more moisture is available, probably from more frequent summer snowfalls, and soluble materials are distributed throughout the soils and do not form surface crusts. Soils with much moisture and those rich in organic matter are classed as intrazonal.

ISSN:0028-8306    

DOI:10.1080/00288306.1967.10426754

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The morphology, physics, and chemistry of Lake Miers (78° 07′ S, 163° 54′ E), a warm freshwater Antarctic lake, are discussed. The presence of rock debris on the floating lake ice has led to the formation of dirt cones and melt pools. Fossil levels of these pools show that the annual ablation is 15–20 cm. Despite a mean annual air temperature of − 20 ° c, the bottom waters of the lake are at + 5 ° C. This is shown to be a natural example of solar heat storage and the observed temperature profile is satisfactorily accounted for. Chemical evidence suggests that the lake has been filled by freshwater containing K, Na, Cl, and O2, and that it is now stagnant below the 4° C depth. In this lower zone Ca, Mg, CO2, and SiO2are diffusing upwards from the lake bed, possibly partly released by anaerobic biological activity.

ISSN:0028-8306    

DOI:10.1080/00288306.1967.10426755

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The geomorphology and glacial history of the Miller Range on the edge of the Polar Plateau in the central Transantarctic Mountains is described. Three high-level glacial erosion surfaces are mapped and these surfaces represent progressive degradation of an original peneplain by successive advances of the continental ice sheet. Extrapolated to the coast they correlate with a summit erosion surface 1,600–1,900 m above the Ross Ice Shelf. During this early Pleistocene period of glaciation, the level of the Polar Plateau was apparently 800–1,000 m higher than at present. Following a major interglacial hiatus, the present glacial valleys were cut, deepened, and filled by ice, which gradually receded leaving a sequence of recessioml moraines. During this younger Pleistocene glaciation the Polar Plateau was no more than 300–400 m above its present level.

ISSN:0028-8306    

DOI:10.1080/00288306.1967.10426756

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

Lake Miers is covered by a thick ice sheet which is domed over most of its area and thrust into sharp debris-covered ridges around its margin. Ridges result largely from compression generated in the ice raft by freeze and thaw. Apart from a narrow moat in summer the ice round the lake shore is frozen fast to the lake bed. The margin of the floating ice raft is thrust over the fast shore ice to form pressure ridges. In the prevailing aridity the ridges ablate relatively swiftly and an equilibrium is attained between the rates of uplift and downwasting. With continued uplift the infrozen gravels migrate to the surface of the ridges and accumulate there as a residual cover. Because of its low albedo the debris cover causes locally increased insolation, and because it is thin, heat is conducted to the underlying ice and ablation is increased. These active and young moraines are quite different from passive and ancient ice-cored moraines. The latter are preserved only because of a thick and insulating debris cover: the Lake Miers ridges exist despite their thin insolating gravel cover and primarily because they are dynamic.

ISSN:0028-8306    

DOI:10.1080/00288306.1967.10426757

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor