卫星遥感信息与华北平原第四纪环境变迁研究

遥感已成为第四纪研究的重要信息源。50年来对华北平原的认识过程,为遥感分析提供了判断和推理的理论依据。卫星遥感信息具有宏观概念与微观论证相结合的特点,为研究华北平原第四纪环境变迁提供了多方面的信息和新的概念:通过线性形迹查明一些新的断裂构造;依据地貌标志和考古、测年记录标定古海岸线;利用多时相对比阐明河道迁移与河槽摆动规律;追踪残存遗迹和剖析开发利用的人文标志;查明湖泊、沼泽的消亡;提出建立数据库用于第四纪环境的再现、模拟和预测等。

SOME INFORMATION OF QUATERNARY ENVIRONMENT CHANGES FROM SATELLITE IMAGE IN NORTH CHINA PLAIN

The satellite image for micro demonstration and macro change monitoring can be used not only to detect the historical vestiges of environmental evolution and change, but to comprehensively study historical background and modern process of natural environment, and to analyze the effect of neotectonic movement, the process of modern force and the interference of human activities.The North China Plain is a compound mainly constructed by Quaternary sedimentary process and also some other multiple processes mixed up together such as flood and alluival fans and deltas, and marine deposits. Since the latest half century, the study on the North China Plain by Chinese geoscientists has experienced five stages, that is, concept detuction; relief surveying and geomorphological mapping; geological drilling and geophysical prospecting; aerial photogrammetry and monitoring on geo-dynamic phenomena; evolution modelling study and multiple dimension analysis.Since 1975, the mosaic imagery maps of the whole and also some local areas of the North China Plain have been published by Landsat MSS images geometrically corrected with different accuracies. The scales are ranged from 1:500 000 to 1:250 000. Multiple information has been provided for the study on Quaternary environment changes.1) Linements and Neotectonic MovementsThe linements and Neotectonic faults have increased 50 percent in Beijing area through ground checking. The Tan-Lu deep fault belt is extended thousand km. The fault belt with NNW strike is run through the North China Plain, Which plays a role in landform and river change control.2) The Seashore Change Since Holocene EpochAccording to the comprehensive analysis on geomorphological marks, archaeological and ¹⁴C dating, six old coast lines have been marked along the Bohai Sea and the Huanghai Sea.3) River Course Migration and River Bed Change155 old river course marks during various periods have been demarcated by using multidate comparison. Among these old river course marks, there are 26 abandoned by the Yellow River since 1855. On the flood and alluival fan of the Yongding River, the old river courses are divided into three stages. The migration of the old river courses and the neck points where the tributaries converged are controlled by neotectonic movement, and appearing regularities.4) Withering Away of Lakes and Changing of DepressionsThere are three groups of lakes and marshland in the North China Plain. Near the Baiyangdian Lake, 23 vestiges of marsh lakes have been discovered by tracing the remaining marks and analyzing the cultural developing marks. The withering process of the old lakes and swamps in the North China Plain has been analyzed.It has been proposed to establish a database for Quaternary environment of the North China Plain, which is used to store remotely sensed data, and ground observation and historical document records to reproduce, simulate and predict environment evolution process. Also it will be further used to be connected with erosion of the Loess Plateau and marine deposit of the Bohai Sea to construct geo-dynamic analysis model for systematical study on internal and external circulation of the sedimentary matter. Pilot study work has been being carried out in the new delta of the Yellow River, the lower reaches of the Yellow River and parts of the Loess Plateau.