Determining the origin of beach ridges in lacustrine basins can often be problematic. The sedimen- tary processes responsible for formation of beach ridges on the north shore of Huangqihai Lake were investigated by us...Determining the origin of beach ridges in lacustrine basins can often be problematic. The sedimen- tary processes responsible for formation of beach ridges on the north shore of Huangqihai Lake were investigated by using ground penetrating radar （GPR）. A 400 MHz GPR antenna was used to achieve a high vertical resolution of 0.044）.08 m. The radar stratigraphy was then determined using principles of seismic stratigraphy. The radar facies （RF） were determined by analyzing internal configuration and continuity of reflections, as well as reflection termination patterns. The identified RF fall into three groups （inclined, horizontal and irregular）. The inclined group consists of RF that display inclined reflections. The horizontal group consists of RF that exhibit predominantly horizontal reflections. In the irregular group, the reflections are typically weak. RF with reflections with gently landward dips in the shore-normal profile are interpreted as washover sheet deposits. RF with steeply landward-dipping and imbricated reflections are interpreted as washover lobes. Washover sheets develop when overwash fails to enter a significant body of water and sedimentation takes place entirely on the relatively flattened topography. Washover lobe development occurs when overwash enters a region in which topography dips steeply landward, and sedimentation takes place on the surface of washover sheets or previous washover lobes. The beach-ridge deposits are interpreted as being formed entirely from vertically and laterally stacked washover sheets and washover lobes. They were formed by wave-dominated processes and secondary overwash processes supplemented by longshore currents.展开更多
基金This paper was supported by the State Scholarship Fund （Grant No. 201406400030）, the National Natural Science Foundation of China （Grant No. 41072084） and Research Fund for the Doctoral Program of Higher Education （Grant No. 20120022130002）. The authors sincerely thank Professor Lars B. Clemmensen of University of Copenhagen for his constructive idea. The authors also thank Beibei Liu, Yonghui Du, Zhaopu Gao and Yanan Miao for their assistance in the field and laboratory. Cliff thanks the Charles T. McCord Chair in Petroleum Geology for support. The authors also thank two anonymous reviewers.
文摘Determining the origin of beach ridges in lacustrine basins can often be problematic. The sedimen- tary processes responsible for formation of beach ridges on the north shore of Huangqihai Lake were investigated by using ground penetrating radar （GPR）. A 400 MHz GPR antenna was used to achieve a high vertical resolution of 0.044）.08 m. The radar stratigraphy was then determined using principles of seismic stratigraphy. The radar facies （RF） were determined by analyzing internal configuration and continuity of reflections, as well as reflection termination patterns. The identified RF fall into three groups （inclined, horizontal and irregular）. The inclined group consists of RF that display inclined reflections. The horizontal group consists of RF that exhibit predominantly horizontal reflections. In the irregular group, the reflections are typically weak. RF with reflections with gently landward dips in the shore-normal profile are interpreted as washover sheet deposits. RF with steeply landward-dipping and imbricated reflections are interpreted as washover lobes. Washover sheets develop when overwash fails to enter a significant body of water and sedimentation takes place entirely on the relatively flattened topography. Washover lobe development occurs when overwash enters a region in which topography dips steeply landward, and sedimentation takes place on the surface of washover sheets or previous washover lobes. The beach-ridge deposits are interpreted as being formed entirely from vertically and laterally stacked washover sheets and washover lobes. They were formed by wave-dominated processes and secondary overwash processes supplemented by longshore currents.
