IIIFカラー高解像度
国立情報学研究所 - ディジタル・シルクロード・プロジェクト
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| IIIFカラー高解像度 |
| Overland to India : vol.2 | |
| インドへの陸路 : vol.2 |
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引用情報
222 OVERLAND TO INDIA
CHAP.
It is evident that such a horizontal filling as the plastic salt loam of the Kevir cannot be a löss formation. It still
bears all the signs of a salt lake bottom. It is indeed, wet /
in winter, and the ground water stands quite close to the
surface. The perfectly level salt layer excludes any sup- y
position of æolian origin. But, as far as I can make out, 0
the conditions in Persia are by no means at variance with
Richthofen's explanation of immense löss deposits, as much 4
as 2300 feet thick, in China and Mongolia. He certainly ti
found no trace of glaciers even on the highest hills of o
China, and considers that the diluvial ice epochs passed by 4
China without leaving any vestiges, owing to the dryness ol
of the climate. The effect of a dry climate is that the fine wind-blown products of weathering fill up all hollows in course of time to such an extent that all inequalities are
smoothed out, and even mounds and small hills are buried II
in them. Thus a flat, basin-shaped salt steppe is formed, on all sides skirted by hills. If the climate then becomes
moist, the salt steppe is turned into a löss basin. The n
precipitation is collected into rivers, which cut deeply into the löss deposits.
During the dry period preceding the ice age the same ~+
æolian deposition probably took place in the enclosed basins of Persia. The only unmistakable traces of löss deposits I found at the margin of the Kevir were at Turut. The village is, as I have already stated, built partly
on, and partly at the foot of, a terrace of löss which falls !
steeply or precipitously towards the flat, even slope which a
runs down to the edge of the Kevir. In the yellow beds of löss, which after rain have a surface as smooth and slippery as the Kevir, the brook of Turut cuts its way down along a furrow, which is shut in on both sides by steep or vertical walls of löss 4o to 5o feet high. The front of the löss bed, towards the salt desert, has a very irregular outline running out in projections and blocks between intruding bays. Of its prolongation east and west nothing is known to me. Northwards the yellow expanse seems to pass, at a distance of perhaps 6 miles, into the grey tone of the present detritus fan which runs up to the foot of the nearest hills. As far as the foot
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