关键词: 古河道, 楼兰

Abstract: During 1978 and 1980, the author investigated into Loulan two times to and discovered on ancient river channel in the city, and did some measurement on the depth of wind-erosion inside and out side the ancient city.The ancient river channel has been seriously winderoed.It can be discerned that its strike is NS-SE. Once the river flowed into the city from NW and out of the city towords SE, finally contributing to the Lop lake.The width of the remains of the "V"formed river bottom is about 8 m The width of the bank is 2m. The depth of the original river channel was about 2-2.6m. On both sides of the river channel, there is apparent bedding with the inclined angle of 15-20° At the bendings of the channel, the inclined angle of the bedding inside the bank is greater than that out side the bank. Some remains of spiral shells have been'found in the channel. Some carbornised boughs have been found buried under the bottom of the river. Various kinds of pottery fragments, boughs, and tree trunks have been found distributed on both banks. The discovery of the ancient river channel has provided scientific evidence for the study of the life of residents in Loulan at that time, of the arrangement of the city, and of the prosperity and recession of Loulan.To measure and estimate the wind-erosion landform, G poitts have been chosen and 14 azimuths have been measured. The regulation found is. the winb erosion depth on the side against wind is greater than that on the opposite side, outside city greater than inside city,in the direction of NE greater than in the direction of SW.The wind erosion chiefly resnlts from NE wind and SW wind, in addition to low level jet-stream and the sinking energy of high level NK wind.From the measurement, the average wind-erosion rate is 3.5mm/year, with the minimum of 2.4mm/year nd the maximum of 4.7mm/year.The measurement of the wind-erosion depth and the estimate of wind-erosion rate can provide new scientific dasis ror sand-desert control,ecological dalance,and oasicprotection.

Key words: Ancient river, wind erosion rate