塔里木盆地南缘古绿洲分布与河流、冰川的关系

依据野外实地考察和考古资料对塔里木盆地南缘河流与其流域内的古绿洲分布情况进行了研究,着重探讨了历史时期以来古绿洲分布规律、迁移过程与河流、冰川特点之间的耦合关系。研究表明,盆地南缘东侧的且末、若羌地区河流及冰川规模小,数量少;其中下游形成的绿洲小,且从汉代至今都在河流出山口处分布,变化不大,而西侧的和田地区反之,河流下游的沙漠中分布着数量较多的大规模古绿洲;汉代的古绿洲多分布在冲积平原下部的沙漠中心,中部则是以唐代古绿洲遗址为主,上部沙漠边缘多为近代和现代绿洲;古绿洲迁移最大距离可达200 km左右;河流年径流量与古绿洲在沙漠分布的距离呈正相关关系。

Relationship between the ancient oasis changes and rivers,glaciers in the southern Tarim Basin

According to the field work, the document record and the archeology resource on the rivers in the Tarim basin and on the basic of the comprehensive study on the distance, the scale and the location of the ancient oases, this paper discusses the relationship between the distribution regularity and development process of the ancient oases and the rivers and glaciers. The characteristics of the ancient oases depend on the size of the rivers. The rivers in Qiemo and Ruoqiang region at the southeast of the Tarim basin are of small scale and runoff but in the Hetian region and in the west of the Tarim basin the rivers are of big scale and runoff. Therefore, the oases in the Altun Mountains are small and change little. The oases lie on the edge of the alluvial plain in front of the mountains from Han Dynasty to nowadays. The large ancient oases mostly are located on the northern slope of the Kunlun Mountain. The ancient oases have large areas and scales and change in a large scale. The oases mostly are sited at the lower reaches of the local rivers in the Han Dynasty and sited at the middle reaches in Tang Dynasty and the modem oasis sited at some middle reaches and the upper reaches. The abandon of the oases were taken place gradually from the lower reaches to the upper reaches. The maximal moving distance is about 200 km. So the temporal and spatial changes of the ancient oases are obviously regular. The different distances of the ancient oases going into the deserts are based on the different amount of fiver runoff and they have significant positive correlation. Their relationship is positive related. In the south of Tarim basin, each 1 x l0s m3 fiver runoff can push the ancient oasis going forward to desert 20.726 km averagely according the regressive model. The capacity and the area of glacier have the similar relationship with the distance and scales of the ancient oasis in desert. The high elevation mountain provides good condition for glacier exist- ence and development. The greater the capacity of glacier, the farther and the larger the ancient oases go into the desert. In the east, the glaciers in the Altun Mountains are of smaller amount and area; so the capacity of glacier and the scale of ancient oasis are smaller. In the west, the glaciers in the Kunlun Mountains show the larger amount and area; so the capacity of glacier and area the scale of ancient oasis are larger.