Название | Polar Exploration |
---|---|
Автор произведения | William Speirs Bruce |
Жанр | Документальная литература |
Серия | |
Издательство | Документальная литература |
Год выпуска | 0 |
isbn | 4064066064396 |
CHAPTER II THE POLAR REGIONS
I have defined the Antarctic Regions as lying within the Antarctic Circle, that is, south of 66½° S. latitude, but in 1892, on board the Scottish whaler Balæna, I found that this definition broke down, for we fell in with polar conditions before we reached latitude 60° S., some 500 miles south-eastward of Cape Horn, in the neighbourhood of the South Shetland Islands. My impressions of the circumstances are as vivid to-day as then, and more vivid, perhaps, than many other even more striking incidents during that and subsequent voyages.
Sailing south-eastward from the Falkland Islands across the breezy southern ocean, we came into weather, although it was mid-summer, having temperatures about freezing-point. This cold weather was accompanied by fairly frequent fogs which occasionally were very dense, till one day, when we were about 80 miles north-east of the South Shetland Islands, the fog divided, opening up a vista at the far end of which a gleam of sunshine revealed a huge shadowy iceberg—brilliantly white. Sailing on we came nearer to the berg, which was several miles off when we first sighted it, and found it to be a mass of ice which probably rose fully a hundred feet out of the water and was about half a mile long. The top of it looked as flat as a billiard table, and the sides were vertical white cliffs; some cracks, mostly vertical and lenticular, were strongly defined, because in them was to be seen the most brilliant and intense blue one can imagine. At the water-line the ice cliff was worn by the lashing of the relatively warm waves (32.3° F.), and here and there were caves at sea-level where green intermingled with intense blue. Into these caves the water rushed with a resounding roar, until each cave was a seething cauldron, and in some cases the spray from these caves rose high into the air. The sea was literally swarming with Cape pigeons and blue petrels, while great finner whales played and spouted in the vicinity of the ship. The Cape pigeons were so numerous that, on putting a small piece of fat over the side of the ship, one could catch them quite easily with an angler's landing-net. The silk tow-net showed that the water was swarming with a small shrimplike creature called Euphausia, several species of smaller crustacea, and some diatoms; the diatoms blocked the meshes of the silk and made the tow-net slimy. In the evening we sighted another berg to leeward, and at night two other icebergs on either bow of the ship. The sun set only a little to west of south, and a light band of brilliant sky stretched along the southern horizon much the same as is seen in Scotland in June. During that night we passed several bergs in the fog, which came down and enveloped us again; we also met some nasty irregular ragged bits of hard clear ice, each about the size of a cottage, called "growlers" by Arctic seamen on account of the sound they made when rolling in the waves. These growlers are literally floating rocks which would rip the sides out of an ordinary iron steamer. We were truly in the Antarctic Regions, although more than 300 miles north of the Antarctic Circle. For this and other reasons I prefer to define the Antarctic Regions as being bounded by the average limits of floating ice. This line is almost entirely north of 60° S., except to the south of the Indian Ocean and to the south of New Zealand and Tasmania, where it dips to the southward. It trends farthest north in the South Atlantic Ocean, reaching about 50° S. to the south of Cape Colony, and 55° S. to the south-east of the Falklands. Within this limit we find the conditions very much as I have described them on that first day when, on board the Balæna, we fell in with the ice.
But besides defining the limits of Antarctic ice, this boundary is useful in other respects, for it includes the whole of the continental land mass of the Antarctic Regions, which at several points protrudes beyond the Antarctic Circle, notably at Graham Land and Wilkes Land. It also includes most of the really typical Antarctic islands, such as South Georgia, the Sandwich Group, South Orkney, or Powell Islands, South Shetlands, Bouvet Island, Balleny Islands, etc. It also excludes continental terminations of South America and South Africa as well as Australia. The Antarctic Regions are of exactly opposite character to the Arctic Regions; whereas in the Arctic Regions there exists a polar basin of considerable depth, surrounded by an almost complete ring of continental land, composed of the northern parts of Europe, Asia and America, in the Antarctic Regions we have an extensive continental land mass surrounded by a continuous ocean. So far we know little of this vast continent, which is probably as large as Europe and Australia combined. What coast-line has been discovered was nearly all discovered before any of the more recent expeditions sailed to the south. It is interesting to note that the depth of the North Polar Basin is more or less equal to the height of the Antarctic continent.
Ross, Wilkes, D'Urville, Biscoe, Kemp, Palmer, Johnson and Morell all made important land discoveries previous to 1844. Since that time the most important land discovery was Coats Land, which not only filled up a gap between Enderby Land and New South Greenland, but which placed the edge of the Antarctic continent 500 miles farther north than Murray and others had mapped it. Of the interior of the Antarctic continent we know but little; the pioneer journey of Armitage, at an altitude of 9,000 feet, gave us our first insight into the nature and extent of the continental ice cap of which we have further knowledge from the journeys of Scott, Shackleton and David. (The Heart of the Antarctic, Sir E. H. Shackleton: London, 1910.)
There are two theories regarding the Antarctic continent: one, that it is one continuous land mass; the other, that it is divided by a channel from the Weddell Sea to the Ross Sea. To my mind all the evidence points to one land mass, and for the following reasons, although it should be noted that Prof. Penck and others adhere to a belief in two. Looking at the map we will find that the outline of the south of South America is almost the same as that part of the Antarctic continent known as Graham Land; each terminates in a pointed extremity which is largely broken up into clusters of islands and tends to turn towards the eastward; each has a group of islands lying to the eastward South America the Falkland Islands, and Graham Land the South Orkneys. We notice also that whereas the west coast of South America is rugged and broken up into many islets and channels, the east coast is of simpler outline. These features also hold good for Graham Land. Looking at the general sculpture of these two lands we find that South America has a high rugged mountain range on the west, parallel with the coast, and broad plains of low elevation on the east; the same features hold good in the description of Graham Land, as far as it is known. The most recent explorations of Dr. Jean Charcot still further emphasise these resemblances. Finally, looking at the geology, we find that both the west coast of South America and the west coast of Graham Land are made up of the same class of folded rocks, composed of gneisses, granites, etc., and that along each coast there is a tendency for active volcanoes to appear; but on the east coast of both lands there are sedimentary rocks of more recent origin with plateau formation. In fact, the only marked difference that occurs is in the glaciation, which is accounted for by difference of latitude.
Now give the globe a half turn round its axis and compare Victoria Land and its islands with Australia and its islands. We will find the outline of Victoria Land on its east coast has a remarkable resemblance to the east coast of Australia. Lying off the coast of Australia we have New Zealand and other islands which have their counterpart in the smaller islands off Victoria Land, notably Balleny Isles, Possession, Coulman, and Ross Islands. The east coast of Australia is flanked by a great mountain range parallel to the coast, which slopes away to the westward, and Victoria Land has exactly the same feature. Geologically both Australia and Victoria Land are plateau formations of similar type and age. The volcanic character of New Zealand compares with the volcanic islands of Balleny, Possession, Coulman and Ross; all are on folded mountain ranges.
There is a further striking feature. The whole of the west coast of South and North America has the same character in being skirted by parallel folded mountain systems, bearing a certain number of volcanoes. This general Eastern Pacific character also holds good for the west coast of Graham Land. So, also, the general type of the Western Pacific appears to be carried over into Victoria Land, and it is obvious that both these systems on the east and on the west of the Pacific Ocean are essentially the same except for secondary modifications. In consequence, we have all coasts of the Pacific, as far as they are known, of exactly similar formation