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| IIIF Color HighRes |
| Scientific Results of a Journey in Central Asia, 1899-1902 : vol.4 |
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Citation Information
THE LAKOR-TSO AND ITS BEACH-LINES. 165
glens open out from the west, south-west, and south. Its eroded watercourse has been obliterated, and disappears before it reaches the gypsum area. South of Camp CIX rises an almost free-standing butte, which, I have no doubt, is nevertheless connected with the range that forms the left-hand, or south-west, boundary of the
valley of Lakor.
From Camp CIX, with the help of two of the Cossacks, and my levelling- tube and tape, I made a levelling of the mountain-slopes that rise west of that camp, my purpose being to ascertain the elevation of the highest visible beach-line above the bottom of the valley. We made our start from the edge of the level, though lumpy gypsum area, and, as I have already said, I estimated its altitude to be 2 m. above the surface of the existing lake. Our starting-point , was situated at least one kilometer from the lake shore. The tube was fixed at 1.50 m. above the ground, so that each successive station up the slope means an increase in elevation by that amount. The distance between the stations was measured with the tape, and decreased pretty constantly as we ascended and as the ascent increased in steepness. The sketch (Pl. 27) shows along the measured line a number of irregularities with a steeper pitch; these are to be ascribed to the beach-lines.
The distance between our starting-point and the first station amounted to 198 m., that is to say we had to advance nearly 200 m. in order to ascend i'/2 m. The next two sections measured 56 and 61 m., then the distance dropped to 35, 16, and 13 m., then increased to 20.7 and to 19. r, but after that remained pretty constant at i o m. or a little over all the way to the foot of a small eminence, which we left on the right. After that however the distance grew as short as 8, 7, 6, and 5 m., and during the last piece of the way it kept between 3 and 4, sometimes 5. The very shortest distance in which there was a rise of I r/2 m. was 3.12 m. The highest point at which the last indications of ancient beach-lines were visible lay just below or on the 5o ni. distance-line from a bed of quartzite that pierces the loose detritus. The number of stations was 85, so that the last or 85th station lies 130.5 m. above our starting-point, or about 133 m. above the then existing level of the lake. The line of measurement ran towards the S. 67° W., towards the summit of the fork. Along this line we passed five beach-lines, all quite distinct, though in point of distinctness they will not bear comparison with those on the mountain-slopes at the east end of the depression. At the highest point on this western end we detected no signs of an ancient beach-line; but I continued my measuring that far, so as to ascend to the same altitude as the highest of the beach-lines at the opposite end of the depression. Thus the highest visible strand-rampart at the outlet of the valley lies at an altitude of 133 m. above
the lake.
We have now therefore to compare the two opposite slopes. The outlet of the valley falls with extreme gentleness northwards towards the southern shore of the lake. On its eastern or right side the valley slopes towards the west, and on the opposite side, that up which we made our measurements, it slopes towards the east. This circumstance is of radical importance, and indeed it is obvious at the first glance; for the beach-lines which occur on the westward-looking versant are incomparably better developed than those on the eastward-looking versant; and this law holds
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