福建海坛岛北部海岸带冲积扇沉积构造及其发育模式
发布时间：2019-04-22 20:09
【摘要】：海岸带冲积扇作为海陆过渡带中的重要沉积地貌单元,蕴藏有丰富的"陆-海-气"耦合作用及其古地理环境变化信息。本文选取福建海坛岛北部的海岸带冲积扇(大砂山)为研究对象,在大砂山表层布设6条累计长度约700m的探地雷达(GPR)测线,结合剖面观察解译以获取大砂山内部沉积构造和沉积序列信息。结果显示:GPR探测图像很好地显示约20m深度范围内的沉积构造信息,可以识别出9种沉积构造雷达相,这些雷达相总体上反映了海岸带冲积扇以泥石流和沟谷洪流为主、并交替有海岸风沙作用的沉积构造特征。综合三维沉积构造信息可知,大砂山为两个冲积扇侧向连接而成的复合体。结合野外地质地貌考察和砂样粒度分析,认为该冲积扇发育过程可分为四个阶段:(1)晚更新世末次间冰期,海岸带老红砂堆积形成"红色沙漠";(2)晚冰期时频发的暴雨洪水,携带南部山区的风化碎屑物质堆积在海岸带形成了冲积扇主体,并覆盖在老红砂剥蚀面上;(3)全新世早中期气候湿润,河流下切侵蚀冲积扇,形成大砂山基本形态;(4)全新世晚期,全球气候转冷,海岸风沙作用兴起,塑造成为现代大砂山的地貌特征。
[Abstract]:Coastal alluvial fan, as an important sedimentary geomorphological unit in the sea-land transitional zone, contains abundant information of "land-sea-air" coupling and paleogeographic changes. In this paper, the coastal alluvial fan (Dashanshan) in the northern part of Haitan Island, Fujian Province, is chosen as the object of study. Six ground penetrating radar (GPR) lines with a cumulative length of about 700m are set up on the surface of Dashanshan. The information of sedimentary structure and sequence in Dashanshan mountain can be obtained by cross-section observation and interpretation. The results show that 9 kinds of sedimentary structural radar facies can be identified from GPR images, which reflect that debris flow and gully flood are dominant in alluvial fan of coastal zone, and that the sedimentary tectonic information in the depth of about 20m can be identified very well, and that 9 kinds of sedimentary structural radar facies can be identified in this paper. And alternately has the sedimentary structural characteristics of coastal aeolian action. According to the information of three-dimensional sedimentary structure, Dashanshan is a complex formed by lateral connection of two alluvial fans. Combined with the geological and geomorphological investigation in the field and the grain size analysis of sand samples, the development process of the alluvial fan can be divided into four stages: (1) the late Pleistocene interglacial period, the old red sand accumulation in the coastal zone formed the "red desert"; (2) the heavy rain and flood occurred frequently in the late glacial period, and the weathering debris from the southern mountain area accumulated in the coastal zone to form the main body of alluvial fan, which was covered on the eroded surface of the old red sand; (3) in the early and middle Holocene, the climate was moist, the rivers cut down and eroded alluvial fan, and formed the basic form of the big sand mountain; (4) in the late Holocene, the global climate turned cold and the coastal wind and sand action rose, which became the physiognomy characteristic of the modern big sand mountain.
【作者单位】： 福建师范大学地理科学学院;福建省湿润亚热带山地生态重点实验室;福建师范大学地理研究所;
【基金】：国家自然科学基金(编号:41271031和41301012) 国家自然科学基金委员会——福建省人民政府促进海峡两岸科技合作联合基金(编号:U1405231) 福建省自然科学基金(编号:2017J01460)联合资助的成果
【分类号】：P736.21
，
本文编号：2463158
[Abstract]:Coastal alluvial fan, as an important sedimentary geomorphological unit in the sea-land transitional zone, contains abundant information of "land-sea-air" coupling and paleogeographic changes. In this paper, the coastal alluvial fan (Dashanshan) in the northern part of Haitan Island, Fujian Province, is chosen as the object of study. Six ground penetrating radar (GPR) lines with a cumulative length of about 700m are set up on the surface of Dashanshan. The information of sedimentary structure and sequence in Dashanshan mountain can be obtained by cross-section observation and interpretation. The results show that 9 kinds of sedimentary structural radar facies can be identified from GPR images, which reflect that debris flow and gully flood are dominant in alluvial fan of coastal zone, and that the sedimentary tectonic information in the depth of about 20m can be identified very well, and that 9 kinds of sedimentary structural radar facies can be identified in this paper. And alternately has the sedimentary structural characteristics of coastal aeolian action. According to the information of three-dimensional sedimentary structure, Dashanshan is a complex formed by lateral connection of two alluvial fans. Combined with the geological and geomorphological investigation in the field and the grain size analysis of sand samples, the development process of the alluvial fan can be divided into four stages: (1) the late Pleistocene interglacial period, the old red sand accumulation in the coastal zone formed the "red desert"; (2) the heavy rain and flood occurred frequently in the late glacial period, and the weathering debris from the southern mountain area accumulated in the coastal zone to form the main body of alluvial fan, which was covered on the eroded surface of the old red sand; (3) in the early and middle Holocene, the climate was moist, the rivers cut down and eroded alluvial fan, and formed the basic form of the big sand mountain; (4) in the late Holocene, the global climate turned cold and the coastal wind and sand action rose, which became the physiognomy characteristic of the modern big sand mountain.
【作者单位】： 福建师范大学地理科学学院;福建省湿润亚热带山地生态重点实验室;福建师范大学地理研究所;
【基金】：国家自然科学基金(编号:41271031和41301012) 国家自然科学基金委员会——福建省人民政府促进海峡两岸科技合作联合基金(编号:U1405231) 福建省自然科学基金(编号:2017J01460)联合资助的成果
【分类号】：P736.21
，
本文编号：2463158
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