IIIF Color HighRes
National Institute of Informatics - Digital Silk Road Project
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| IIIF Color HighRes |
| Southern Tibet : vol.7 |
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Citation Information
THE SELF-CONTAINED BASINS OF TIBET.
496
few lake basins or depressions which, therefore, are situated in the midst of the Kwen-lun System. Two of these basins are considerably larger than the average
basins along the southern foot of the system , and one of them, that of the Lake Ayagh-kum-köl, belongs to the very largest of the whole plateau-land. It has an area of 26,550 sq. km., whereas the other basin, that of Achik-köl, is not half as large, or 12,200 sq. km. Comparing the absolute altitude of these two lakes with that of one of the . southern Kwen-lun lakes, for instance No. II, we find how the lake basins of this part of Tibet gradually become lower from south to north, No. II having an altitude of 4 900 m., Achik-köl of 4365 m., and Ayagh-kum-köl of 3867 m.
The next series of lakes is not quite as sharply defined as those along the base of the Kwen-lun, though here the route of Wellby and Malcolm is of great
assistance. To the same series belong some lakes described by DEASY, RAWLING,
DE RHINS, LITTLEDALE and myself. Some of the most important, in all ten, are entered in my list. Their basins are as a rule comparatively small, that of Lake Markham' being
the largest with an area of 5275 square km. As to the proportion between the area of the lake and the area of its drainage basin, no general rule can be traced. In one case, viz., the little lake to the E. N. E. of Chang-lung-yogma, its area is only i t- of its drainage basin, while my lake No. XVIII as well as Arport-tso are of their drainage basins.
Proceeding one step farther south I have calculated the areas of thirteen lakes
and their basins, all belonging to the central parts of the plateau-land. The number of such lakes is of course very great, though I have only chosen those the surroundings
of which are fairly well known. They are not bounded by a latitudinal valley
between two mountain systems, but are only taken at random here and there in the central parts of Tibet. The largest of these lakes is the one called Lac des
Hemiones by de Rhins and having an area of 562 sq. km. according to his map.
Both its form and its size are, however, doubtful, especially as DE RHINS and GRENÀRD call its northern' half No. 5 and its southern half No. 6. Probably it is two lakes,
perhaps one fresh and one salt, as is an ordinary combination on the plateau-land. The largest drainage basin of the group in question, viz., the one I discovered in 1901, has an area of 7 5 5 o sq. km. Here the relation between the lake and its drainage area is as I: 5o, whereas the same relation in the case of Lac des Hemiones is I:6. Of course, these figures are only approximate.
The next series of lake basins shows a high degree of continuity. It begins in the west with Panggong-tso and comes to an end in the east with Selling-tso.
I I am principally against the habitude of some explorers to baptize lakes and mountains with European names, but as the names already given are entered upon all European maps I cannot help using them. My views in this question are explained in a little article: European names in Tibet, Geografiska Annaler, Stockholm 192o, p. 363 et seq.
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