基于GPR图像的福建海坛岛北部海岸冲积扇沉积构造及其成因的初步研究

发布时间：2018-04-25 20:38

本文选题：探地雷达 + 冲积扇　；参考：《沉积学报》2016年04期

【摘要】：福建海坛岛北部海岸发育一座覆盖淡灰黄色风成砂层、相对高度达30 m的大沙山,外貌很像风成大沙丘,但同时又具有冲积扇形态。其成因和沉积环境有待考证,而探明大沙山内部沉积构造是判别其成因的主要途径之一。在野外考察的基础上,运用探地雷达(GPR)对大沙山内部沉积构造进行探测,获得约20 m深度范围内的沉积构造图像数据。结果表明:大沙山中上部发育由棱角状砾石或粗砂细砂组成的沉积旋回和沟槽沉积构造,显示出冲积扇上部的沉积构造组合特点;中下部层面中交替呈现弧形沉积构造,大沙山南侧发育有向南倾斜28°~30°的前积层理。结合大沙山西侧冲沟剖面沉积构造、大沙山表面的棱角状砾石特征以及现代风沙地貌分布规律,初步认为大沙山是山前多期沟谷洪流携带的碎屑物沉积形成的冲积扇残余堆积体,沉积间隙受海岸带风沙活动影响。
[Abstract]:On the northern coast of Haitan Island, Fujian Province, there is a pale yellowish eolian sand layer, which is about 30 m high. Its appearance is very similar to that of wind-formed sand dune, but it also has the shape of alluvial fan at the same time. Its origin and sedimentary environment need to be studied, and it is one of the main ways to identify the origin of Dasha Mountain. On the basis of field investigation, ground penetrating radar (GPR) was used to detect the sedimentary structure in Dasha Mountain, and the sedimentary structure image data were obtained in the depth of about 20 m. The results show that sedimentary cycle and trench sedimentary structure are developed in the middle and upper part of Dasha Mountain, which consists of angular gravel or fine sand, which shows the characteristics of sedimentary tectonic assemblage in the upper part of alluvial fan, and alternately arcuate sedimentary structure in the middle and lower layers. On the south side of Dasha Mountain, there are antecedent stratigraphy tilting 28 掳to 30 掳south. Combined with the sedimentary structure of the west side of Dasha Mountain, the characteristics of the prism and gravel on the surface of Dasha Mountain and the distribution law of modern aeolian geomorphology, It is preliminarily considered that Dasha Mountain is a remnant deposit of alluvial fan formed by detritus deposited by multi-stage gully flood current in front of the mountain, and the sedimentary gap is affected by the aeolian sand activity in the coastal zone.
【作者单位】：福建师范大学地理科学学院;湿润亚热带生态地理过程省部共建教育部重点实验室;福建师范大学地理研究所;
【基金】：国家自然科学基金项目(41271031;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(U1405231)~~
【分类号】：P736.21

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