Characteristics of the Yihe River Paleo-Valley near the Linyi Jiuqu Yihe River Bridge, Shandong Province

摘要

The Yihe River's stratigraphical cross-section near the Jiuqu Yihe River Bridge of Linyi City was selected as the research zone. The stratigraphical cross-sections of paleo-valley were established with bore datum near the Jiuqu Yihe River Bridge. The geophysical seismic imaging method of shallow stratigraphy was applied to detect drilling. Data of 1 OSL dating was obtained through the analysis of the sample collected from the bottom of the paleo-valley near the G327 Yihe River Bridge and of 2 ~(14)C dating were obtained through the analysis of the samples collected in burial terrace of the Benghe River. It is concluded that: the Yihe River paleo-valley is located on the fault zone. Near the Jiuqu Yi River Bridge, the paleo-valley below 53～55m is the paleo-valley of the Yihe River and Benghe River in the Last Glacial Maximum (LGM). During the LGM, the Benghe River flowed into the Yihe River in the downstream of the Jiuqu Yihe River Bridge. The paleo-valley above 54m is considered as the paleo-valley of the Yihe River since the LGM. After the Late Glacial, the Benghe River flowed into the Yihe River at the present location. The Yihe River paleo-valley has a relatively large width-depth ratio, which means a wide and shallow river channel with the characteristics of braided river.