A research of influence of neo-tectonic movement on alluvial rivers: Review and prospect

Abstract

The study of neo-tectonic movement and its impact on alluvial river can deepen the understanding of the complex response theory in a geomorphic system and the complex hypothesis of multi- cycle deposition, and investigate thoroughly the relationship between sedimentary sequence and basin depositing processes, which can be widely applied to earth science, water engineering, traffic transportation, communications, oil and gas exploration and development, etc. In this paper, it is mainly reviewed the research progress of the influence of neo-tectonic movement in alluvial rivers, and neo-tectonic movement is described very briefly.In the embryonic period of the neo- tectonic movement, the study of the drainage pattern in a basin and the river towards controlled by the neo- tectonic movement, had been increasingly popular as a new discipline, but mainly focused on the geologic interpretation. Since the 1970 s,research on the neo-tectonic stress field can help us understand the neo-tectonic mechanism and dynamics. In author's point of view, active tectonics can be taken as part of the neo- tectonic movement, and the type and ratio of neo- tectonic movement has significant effect on alluvial river morphology and channel evolution, including the plane form, channel width, longitudinal profile, cross section, sinuosity, braided index, cutting strength and range, channel pattern,transport type and amount of sediment, which shows the complexity, hierarchy, sensitivity and prophetic. Influenced by active fold, uplift and depression on river longitudinal profile development, the compensation of subsidence by the sedimentation is concerned specially. As for the influence of neo- tectonic movement on alluvial river plane shape, the sinuosity was taken as the barometer of alluvial river in response to neo-tectonic activity. As for the effect of active fault on river development and evolution, sensitivity and prophetic are especially mentioned. This paper deals with the research progress in the bedrock exposed on riverbed by active uplifting, which resulted in developing both pressed and release meandering along upstream and downstream, respectively, and the so called "New structure", formed by river erosion. The traditional research methods and techniques are not generally described but mentioned that the experiment simulation has obtained remarkable achievements at home and abroad, and the mathematical simulation is just unfolding. It is prospected that at first, to pay attention to the crossing, permeating and comprehensive research of neo- tectonic movement impacting to alluvial river, the second to focus on effects of rapid tectonic movement to alluvial river, the third to observe regularly lifting rate of neo- tectonic movement, the riverbed evolution and sediment transportation in the neo-tectonic active area, the fourth, to take caution more with the physical model experiment and mathematic simulation, in which there is a great space for development, and finely to strengthen the cooperation and fusion of research ability.The study will enter a new stage of development.