Abstract:

The Last Glacial Period, popularly known as the Ice Age, was the most recent glacial period, which is characterized by high frequency and high amplitude climate fluctuations and unusually cold. How the river system responds to the climate change in this period deserves attention? According to classical geomorphology theory, the behavior of the river incision occured during the interglacial period or glacial-interglacial transition, while the fluvial aggradation occurred during the glacial period. However, this paper believed that the river incision occurred during the Last Glacial Period is an indisputable fact based on summarizing the research results of river geomorphology in recent years. To begin with, the traditional models of river terrace formation were summarized. The simple tectonic driving model is not reasonable because the climate change plays a very important role. The single climate change cannot drive the formation of multistage and higher elevation terrace, so crustal uplift is a necessary factor. The climate change is a key factor for the formation of river terraces by driving the river fill-cut behavior transition. Three models of the river system response to climate change during the Last Glacial Period are summarized: (1) massive flooding events caused by high-frequency climate fluctuations drive rapid the river incision; (2)the high-frequency climate fluctuations combining rapid crustal uplift drive the river incision; (3) the coastal plain sea level which drops significantly triggers the river incision. Those models have very important guiding significance of understanding the river system responses to the short-term climate change and the judgment on the origin of river terraces.

Key words: Last Glacial Period, river terrace, river incision, abrupt climate change, base level of erosion