downcutting

基本解释

The deep troughs on the Three Gorges valley bottom are formed by river downcutting along the structurally zones on the background of regional tectonic uplift.
结果表明：（1）三峡坝区河谷深槽是在三峡地区构造抬升过程中，水流顺构造裂隙强烈侵蚀下切而形成的；
Besides the above, oil reservoirs in member 9+10 of Yanan formation in Jurassic are controlled by vertical migration pathway generated by riverway downcutting.
另外，侏罗系延安组延9+10段油气成藏还受到古河道下切形成垂向运移通道控制。