长江三峡地区第四纪以来新构造上升速度和形式

本文以长江三峡地区各级夷平面和阶地作为重要标志,用地层学、古地磁测年、热释光测年和14C测年等手段,确定了它们的时代,从而分别计算2Ma、0.73Ma和0.2Ma以来的新构造上升速度。本文还探讨了新构造上升的特征:（1）长江三峡是一个以巴东为中心的不对称的新构造穹形隆起区,宜昌以东和万县以西是相对坳陷区;（2）2Ma以来,新构造上升节奏为缓慢—较快—较慢;（3）0.73Ma以来,新构造上升中心有向东迁移的趋势。

NEOTECTONIC UPLIFT VELOCITY AND TYPE ALONG THE CHANGJIANG RIVER DURING QUATERNARY

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.