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第四纪研究 1990
NEOTECTONIC UPLIFT VELOCITY AND TYPE ALONG THE CHANGJIANG RIVER DURING QUATERNARY
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Abstract:
In the Sanxia Gorge (the Three Gorges) area along the Changjiang (Yangtze) River, there are many steps of planation surface and river terrace (PS&;RT), being the important marks of neotectonic uplift, the ages of which were determined by means of paleomagnetism dating, thermoluminescence dating and radio carbon-14 dating. According to the ages and appearance of PS&;RT, the author calculates the neotectonic uplift velocity and represents its type in the Sanxia Gorge area during Quaternary. The main conclusions of this paper are as follows:1. In the central zone of the Sanxia Gorge (Wushan to Zigui), the neotectonic uplift velocity was 0.37—0.47 mm/a during the last 2 Ma; 0.59—0.73 mm/a during the last 0.73 Ma; 0.38—0.43 mm/a during the last 0.20 Ma. In other words, average 0.28 mm/a during 2—0.73 Ma B.P.; 0.76mm/a during 0.73—0.20 Ma B.P.; 0.38—0.43mm/a during 0.20—0 MaB.P.2. The Sanxia Gorge area is a unsymmetrical neotectonic uplift dome-zone, contrasting sharply with which, the sides to the east of Yichang County and to the west of Wanxian County are both relative depression zones.3. During the last 2 Ma, the neotectonic uplift rhythm was slow, fast, rather slow.4. During the last 0.73 Ma, the neotectonic uplift centre of the Sanxia Gorge area had been tending to move eastward.