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

> > > >
Color Image Gray High Res. Image PDF Graphics   Japanese English
0235 Explorations in Turkestan 1903 : vol.1
Explorations in Turkestan 1903 : vol.1 / Page 235 (Color Image)

Captions

[Photo] 142 Terrace wall of the Kan Su, west of Kashgar, showing horizontal gravel above tilted Mesozoic strata. On the left or north side are the coal measures; on the right are the vermilion-red beds. Between the two can be detected a slight unconformity, A.

OCR Text

 

'i1

RECONNAISSANCE IN CENTRAL TURKESTAN.   205

nor does this show the full complexity of the problem. In the valley of the Ispairan Su, south of Marghilan, for example, gravels of two and possibly three ages can be detected. The oldest is a very coarse deposit three or four hundred feet thick, which is cemented into solid conglomerate by calcite from the limestone walls. A deep valley was then cut in the conglomerate, so that its remaining portions form a terrace several hundred feet above the stream (fig. 144). This valley was then filled, though to a much less height than before, with gravel of the saine sort as the first, except that it is not cemented so firmly into conglomerate. In this second conglomerate another valley has been cut ; and there are places where the filling and cutting seems to have been repeated a third time on a still smaller

Fig. 142.—Terrace wall of the Kan Su, west of Kashgar, showing horizontal gravel above tilted Mesozoic strata. On the left or north side are the coal measures; on the right are the vermilion-red beds. Between the two can be detected a slight unconformity, A.

scale. If all this is due to deformation it means that there has been an extraordinarily complex series of palpitations—now up, now down—and that while the upward movements have been parallel over large areas, the downward movements have occurred erratically here and there in such a way that the terraces of valleys close beside one another are of different types, or that the upper part of a valley has merely been cut again and again, while the lower part has been both cut and filled an equal number of times. If, then, the theory that the terraces are due to movements of the crust can not be said to be absolutely untenable by reason of the complications that it involves, it certainly matches the facts only indifferently well.