摘要:
选择沂河汤头—刘道口段作为研究河段.在船流街—解家庄断面进行了电测法物探和钻探工作.搜集了柳杭橡胶坝、解放路沂河大桥、陶然路沂河大桥、罗程路沂河大桥等钻孔资料.根据物探、钻探结果及钻孔资料,绘制了船流街—解家庄、柳杭橡胶坝附近、解放路沂河大桥附近、陶然路沂河大桥附近及罗程路沂河大桥附近5个断面的沂河古河槽地质剖面示意图.在船流街、解家庄、柳杭、祊河大桥南岸及陶然路大桥附近沂河河槽等剖面采集了14C及光释光(OSL)年代样品,样品分别在美国BETA实验室、北京大学AMS 14C实验室、南京师范大学光释光实验室等进行了测试,获得了26个年代结果.结论认为,船流街附近约70 m以下、柳杭橡胶坝附近约69.53 m以下、解放路沂河大桥附近约55.09 m以下、陶然路沂河大桥附近约50.36 m以下、罗程路沂河大桥附近约56.35 m以下的河槽,为末次冰期最盛期时的沂河古河槽,古河槽宽深比较大,河槽宽浅;沂河古河槽底部基岩岩性复杂,断裂带发育.由于断裂构造、岩性、支流汇入等,沂河古河槽在解放路沂河大桥、陶然路沂河大桥附近形成局部深切;末次冰期最盛期,沂河汤头—刘道口段属于辫状河.
Abstract:
The Tangtou–Liudaokou reach of the Yihe River is selected as the research object. The authors carried out electrical sounding and drilling work along Chuanliujie–Xiejiazhuang cross section. Drilling data of Liuhang rubber dam, Jiefang Road Yihe Bridge, Taoran Road Yihe Bridge and Luocheng Road Yihe Bridge were selected. Based on electrical sounding and drilling results and drilling data, five pieces of stratigraphical cross sections for the location of the incised valley were drawn. After that,14C and OSL samples of Chuanliujie cross section, Xiejiazhuang cross section, Liuhang cross section, Benghe River Bridge south shore and riverbed near Taoran Road Bridge were collected. The samples above were tested at the BETA Analytic Radiocarbon Dating Laboratory, AMS 14C Laboratory in Peking University and OSL Laboratory in Nanjing Normal University by14C and OSL methods. Twenty-six results were obtained and the conclusions are as follows: The incised valley about –70 m below Chuanliujie drill hole, about –69.53 m below the area around Liuhang rubber dam drill hole, –55.09 m below the area around Jiefang Road Yihe River Bridge drill hole, –50.36 m below the area around Taoran Road Yihe River Bridge drill hole and –56.35 m below the area around Luocheng Yihe River Bridge drill hole constitute the incised valley at the last glacial maximum period. The lithological characteristics at the bottom of Yihe River channel are complicated. Local deep cut was developed at Jiefang Road Yihe River Bridge and Taoran Road Yihe River Bridge because of fractural structure, lithology and branch inflows. Yihe River incised valley's breadth depth ratio is large, the channel is wide and shallow, and hence it belongs to the braided river.
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