IIIF Color HighRes
National Institute of Informatics - Digital Silk Road Project
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| IIIF Color HighRes |
| Scientific Results of a Journey in Central Asia, 1899-1902 : vol.1 |
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Citation Information
326 THE TSCHERTSCHEN DESERT.
in the boundary ones; but as a matter of fact they were absent from the most of them. I have never experienced a violent rain in this desert, and in fact it is shut in
on all sides by lofty chains of mountains; still that is no proof that it never does
rain there, for it can indeed rain, even though it be only once in ten or twenty years. On the other hand, I have twice seen it rain quite briskly at Kara-
koschun, in 1896 and again in 1900, on both occasions early in the summer. But
that snow falls in the desert we were very soon to have a convincing proof. It appears therefore likely, that the desiccation belts to which I have called atten-
tion are probably caused by chance rains. The reason they do not occur in the
neighbouring bajirs may be because these latter lie at a higher level, whereas the little, oval-shaped bajir being deeper, the surface moisture in it evaporates more
slowly owing to the nearer proximity of the ground-water underneath. The dust which settles in this bajir after rain adheres to the moist ground, and in no wise affects the colouring of the different belts; whereas in the adjacent bajirs, where the surface is dry, the dust forms an even coating of uniform colour throughout.
The most noticeable characteristics in the contour of these bajirs are the steep wall of sand on the east, and the leeward southern face, often equally steep,
though not so high, of the thresholds. On the other hand, the sandy slopes on the west of the bajirs and on the north side of the thresholds have a much gentler ascent, and consequently the contour of the base of the sand is here rather irregular.
In a bajir such as No. 20 one is amazed to find no trace of sand in its interior. It is entirely surrounded in every direction by veritable mountains of sand,
and I was also witness of strong gales from the south-south-west and the north-
north-east, and especially in spring and summer of violent gales from the east and east-north-east; yet not one grain of sand is wafted out upon its slightly granulated
surface — schor. It is as though it were entirely tabu to, and fenced against, all
such encroachments. On the other hand, in one place we found some gypsum. The ground, in the bajir in question, was so hard that we were able to travel along
the part of it which corresponded to the softest part in all the preceding bajirs. In
the sand there is, as it were, a certain power of cohesion or attraction, whereby this »viscous» material holds tenaciously together. As an actual fact, the cohesiveness
must really be attributed to the winds, and to the extremely regular deviation which they are forced to make when they blow close to the surface of the earth, as well as to the gradually modelled relief of the desert; hence all that the sand has to do is to follow along the routes which are in this way prescribed for it.
The threshold at the southern extremity of bajir No. 20 is unlike its predecessors, and this, as I have already stated, led to our losing our way in the high sand. Although there were small depressions to both the east and the west, there were none along the route we were following. The leeward flank of the eastern dune-wall appeared to be broken. Accordingly we pursued our way at haphazard, taking no notice of the depressions, trusting that, sooner or later, we should hit upon a fresh chain of bajirs. But this did not happen until after we had travelled 4 km. through the heavy sand, and even then the hollow in which we encamped bore little resemblance to a typical bajir, for it was choked with sand.
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