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TAKLA MAKAN
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TAKLA MAKAN , the Central Asian See also:desert which lies between the N. See also:foot of the Kuen-lun ranges and the wide See also:curve of the See also:Tarim See also:river on the W., N., and E. It appears to be naturally divisible into two parts by the river See also:Khotan-darya, and the name applied to the western See also:part between that river and the Yarkand-darya (Tarim) is the desert of Takla Makan proper, while the part between the Khotan-darya and the See also:line of the See also:lower Tarim and the See also:Cherchen-darya is known as the desert of Cherchen. The former is occupied almost entirely by See also:sand-See also:dunes. Sand mountains range in See also:altitude from 6o ft. up to as much as 300 ft. The only breaks in this See also:sea of sand-waves " are a few small patches of alluvial See also:clay. Often two distinct systems of dunes can be distinguished; one See also:system, consisting of the larger concatenations, stretches from E. to W., while the secondary or transverse dunes run from N. to S. or from N.E. to S.W. The steeper faces of the dunes and of the dune-accumulations are fer the most part turned towards the S., the S.W. and the W., that is, invariably away from the direction of the prevailing winds; but in some parts the steep faces are those fronting the E. and the S. In the desert of Cherchen, however, where the See also:general height of the dunes in the N.E. is uniformly greater than in the desert of Takla Makan proper, reaching up to 350 ft., the configuration is complicated by the See also:appearance of elongated expanses of level clay called bayirs, varying in See also:size from See also:half a mile to a dozen See also:miles in length, barren and tinged with saline deposits in the See also:middle, with scanty vegetation around, and lofty sand-dunes overhanging them on both sides. These elliptical, cauldron-shaped basins all stretch from N.E. or E.N.E. to S.W. or W.S.W., and are arranged in See also:long curving chains, the successive depressions being parted by transverse ridges of sand. They owe their configuration in See also:great part, perhaps entirely, to the prevailing See also:wind. On perfectly level ground the dunes are crescentic in shape, have a steep See also:face towards the W., are highest in the centre, and slope away in each direction towards the two horns or cusps of the See also:crescent. On the windward See also:side they have a See also:convex, See also:spoon-shaped slope, regularly formed, but crumpled by tiny sand-waves or ripple-marks. " With regard to the large accumulations of sand (in the desert of Cherchen) we have ascertained the following See also:laws—(1) In the N. of the desert they turn their steep faces towards the N.W., in the middle towards the W.N.W., and in the S. towards the W. and W.S.W.; (2) their eastern slopes ascend rather slowly towards their crests; (3) on the other side their steep leeward faces go down sheer at an See also:angle of 33°, or else in two or three steps; (4) their See also:mass diminishes towards the S.; (5) they are each built up of an innumerable number of individual dunes; (6) although their See also:relief is influenced by winds from other quarters than the predominant, their mass is unaffected by them: (7) it is their varying breadths which give rise originally to the thresholds, and consequently to the formation of the bayirs ' (Sven Hedin, op. cit. i. 362). The bayirs become progressively rarer, less distinct, and smaller in size as one advances from E. to W. At the same See also:time the arrangement of the sand-dunes grows more and more irregular, and the dunes themselves plunge steeply down towards the W., the S., and the S.W., and are See also:drawn out towards the N.N.E. and S.S.W., the N. and S. and the N.W. and S.E. In that part of the desert two systems of dunes are distinguish-able, intersecting or rather See also:crossing over one another diagonally or at right angles. In the extreme See also:west, at Ordan-Padshah, between See also:Kashgar and Yarkand, the dunes travel annually some 13 ft. towards the S.E., not towards the S.W. The See also:principal cause of the difference between the arrangement of the sand-dunes in the desert of Cherchen and the arrangement of the sand-dunes in the desert of Takla Makan proper in the W. is the wind. In the latter, winds from several quarters co-operate to See also:mould the relief of the desert into capricious and changing outlines; but in the E. the wind blows not only with greater regularity from one settled direction, the N.E. or E.N.E., but also with much greater violence. Indeed, it is in the open Lop See also:country, where the mountains, the Kuruk-tagh on the N., and the Astin-tagh on the S., are the nearest to each other, that the wind develops its greatest and most concentrated See also:energy.' In the E., where the sand waves are most exposed to the fiercest wind, they See also:form elongated waves, distinctly out-lined, corresponding to the breakers of the ocean. They disseminate themselves westwards over the desert in ever-widening concentric circles. The curving courses of the Tarim and the Koncheh-darya are the only check upon the invasion of the Takla Makan by the sand which is generated in the desert of Lop or further E. and N. in the mountains which See also:girdle the desert of See also:Gobi. But the former river is itself encroaching upon the N.E. margin of the desert, and pressing more and more towards the S.W. With regard to the origin of the stupendous masses of sand that fill the See also:basin of the Tarim, K. Bogdanovich considers them to consist for the most part of the disintegrated products of the See also:fine-rained alluvial See also:clays of the desert itself. On the other See also:hand, G. N. Potanin and V. A. Obruchev both seek for its origin in the hard rocks of the mountains which encircle the deserts; and in this view, subject to certain modifications, Sven Hedin is disposed to agree. But he adds 2 that the masses of sand themselves " are ' Sven Hedin, op. cit. i. 364. Y Op. cit. if. 448. derived from three See also:separate See also:sources, in part directly, in part in.. directly—(1) the See also:direct transportation by the wind of the products of disintegration from the adjacent mountains, whether sandstones or crystalline rocks; (2) through the activity of the wind operative amongst the arenaceous alluvia of the See also:rivers and temporary lakes; (3) through the sand that was already See also:present in the See also:soil, and which became exposed in rings more or less concentric in proportion as the former (Central Asian Mediterranean) sea dried up." Of these agencies the river Tarim makes by comparison much the smallest contribution of disintegrated material to the See also:volume of sand. The See also:area covered by sands in the desert of Takla Makan proper is estimated at nearly i i6,000 sq. m., and the area covered by them in the desert of Cherchen at nearly 143,000 sq. m. Vegetation and See also:animal See also:life are extremely scarce. The former is practically confined to various See also:steppe See also:plants, kamish (reeds), tamarisks (almost invariably growing on See also:root-mounds), and poplars. The animals are See also:hares, rats and one or two other rodents, foxes, and in a few places the See also:wild See also:camel. The See also:climate is one of extremes. At Merket on the W. See also:verge of the desert of Takla Makan proper the winters are See also:cold, though the snowfall is small, while the summers are hot. In the desert of Cherchen a temperature of -22° F. has been observed in the See also:depth of See also:winter, and there See also:snow sometimes falls heavily. During the sand-storms which sweep over the region in See also:spring, the thermometer drops as much as 10° or 12° F. below zero. On the other hand, a temperature as high as 86° has been recorded in the end of See also:April (cf. See also:Goal). It is only in winter that this appalling desert can be crossed with any degree of safety. It is destitute of See also:water, but in winter it is possible to transport See also:ice on the backs of camels. Some-times for days together the desert is enveloped in an impenetrable dust-haze, which chokes and smothers every living creature. In the second half of the 13th See also:century Marco See also:Polo See also:left a vivid description of this desert and related legends associated with it (see the edition of his travels in See also:English by See also:Sir II. See also:Yule, ed. 1903). The fullest See also:account by a See also:modern writer is that given by Sven Hedin hr his Scientific Results of a See also:Journey in Central See also:Asia, 1899–1902 (Stock-holm, vols. i. and ii. 1905–6) ; see also his Through Asia (See also:London, 1898), vol. i. For See also:archaeology, see See also:TURKESTAN. (J. T. Additional information and CommentsThere are no comments yet for this article.
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