Southern Tibet : vol.4 / Page 332 (Color Image)

0332	Southern Tibet : vol.4

In the afternoon the wind increased to a storm, coming from S. 85° W. It
was interesting to witness the impenetrable clouds of dust and sand which now again
were driven along the ground. The whole landscape around at once was concealed,
even the nearest hills to the east disappeared completely. It was like a desert storm
in *Takla-makan*. The solid material was swept along the ice across the lake. Where
the ice is uneven, forming small waves, some coarser material remains on the lee
side and will cause some melting the next time the sun returns. At seasons when
there is no ice, the storms must contribute very considerably to fill up the basin of
the lake. We have already found how very shallow it is, and seeing these heaps
of material, one is rather astonished that the whole basin is not quite filled up. As
a rule, the situation of the isobaths, however, is explained by the transporting acti-
vity of the prevailing W. S. W. wind, for the deepest part of the lake is situated
in its eastern half; the western being more directly exposed to the filling action
of the wind. Remembering that this destructive transporting and filling activity
goes on every year for thousands and hundreds of thousands of years, one is able
to realize the result we find in the level forms and flat gradients of the Tibetan
highlands.

Nain Sing exaggerates the S. W. basin of the lake and makes it too broad.
But as a matter of fact it is surprising that he has given the whole lake a form
that is not very far from reality. This tells a good deal in favour of his capacity
of observation. By passing only along one side of a lake, it is very difficult to
draw even an approximately correct contour of its shore. This may easily be seen
from Pan. 117A and 117B, Tab. 21, where we seem to be surrounded by a ring of
mountains, all of about the same altitude, only those to the N. E. and E. N. E., just
behind our camp, seem to be higher on account of the short distance. The mountains
south of us were called *Tagrak-tangu*.

Our fourth sounding line goes W. S. W. across the lake and is 11 km. in length.
A long distance out from *Camp CI*, the lake is so shallow that the ice is resting
directly upon the black mud and ooze of the bottom, as may easily be seen in the
openings of cracks. The cracks and crevasses, as a rule, run north and south, the
long stripes of white salt, in the direction of the wind. Much of this salt is as if
fixed to the ice, but still more is driven by the wind to the E. N. E., and out over
the eastern plain. This action tends to decrease the salinity of the lake, as a certain
amount of salt is carried away from the water in this way, every year. But on the
other hand, the rainwater of the whole region finally flows into the lake, and takes
a good deal of the windblown salt back to it. At any rate the salinity increases
from year to year, though it is not yet strong enough to make animal and vegetable
life impossible. The salinity also increases as the lake dwindles, as is readily visible
from the beach-lines.

National Institute of Informatics - Digital Silk Road Project
Digital Archive of Toyo Bunko Rare Books

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National Institute of Informatics - Digital Silk Road Project Digital Archive of Toyo Bunko Rare Books

Citation Information

OCR Text

National Institute of Informatics - Digital Silk Road Project
Digital Archive of Toyo Bunko Rare Books