地理学报 ›› 2002, Vol. 57 ›› Issue (3): 301-309.doi: 10.11821/xb200203006

• 论文 • 上一篇    下一篇

博鳌地区沙坝-泻湖沉积及探地雷达的应用

殷勇1, 朱大奎1, 王颖1, 葛晨东1, I.PeterMartini2   

  1. 1. 南京大学海岸与海岛开发教育部重点实验室, 南京210093;
    2. Dept. Land Resource Science, University of Guelph, Ontario, NIE 4E5, Canada
  • 收稿日期:2001-12-17 修回日期:2002-03-06 出版日期:2002-05-25 发布日期:2010-09-06
  • 作者简介:殷 勇 (1964- ), 男, 博士, 海洋地质专业, 现在从事博士后研究。E-mail: wiyin@263.net
  • 基金资助:

    中加高校合作项目(CCHEP282/19736)

On Barrier-Lagoon Development and GPR Application in BO'AO Area

YIN Yong1, ZHU Dakui1, WANG Ying1, GE Chendong1, I. Peter Martini2   

  1. 1. The Key Laboratory of Coast and Island Development, Nanjing University, Nanjing 210093, China;
    2. Dept. of Land Resource Science, University of Guelph, Ontario, Canada NIE 4E5
  • Received:2001-12-17 Revised:2002-03-06 Online:2002-05-25 Published:2010-09-06
  • Supported by:

    Project of the Cooperation between China and Canada, No. CCHEP282/19736

摘要:

通过钻孔资料和探地雷达 (GPR) 反射剖面, 揭示了海南岛东部博鳌地区晚更新世以来沙坝-泻湖体系沉积序列和内部反射结构。探地雷达 (GPR) 给出了有关沙体厚度、岩性特征、潜水面深度、海水侵入范围以及沙体含水性等重要参数,是海岸带环境调查的有效手段。通过和钻孔资料的对比,在玉带滩海岸沙坝上部层序中识别出两套具有区域意义的反射波组,南岗村沙洲浅滩识别出一套反射波组。综合分析表明,博鳌地区沙坝-泻湖体系晚更新世以来随海平面的上升经历了基岩侵蚀→河流、河漫滩相→泻湖→海岸沙坝、半封闭泻湖、河口湾的演化过程。

关键词: 沙坝- 泻湖体系, 沙洲浅滩, 沉积序列, 探地雷达 (GPR), 反射波组, 博鳌

Abstract:

A suite of sedimentary sequences and a three-dimensional (3D) observation of coastal bar and shoal deposits from sandy gravel coast zone in Bo'ao, eastern Hainan Island were made using cores, outcrops and ground-penetrating-radar (GPR) profiles. According to litho-facies distribution, three sedimentary sequences are distinguished in sedimentary columns, which constitutes an upward coarse-fine-coarse cycle. GPR reflectors show that water table in the area is located about 6 m below the surface and the reflective signals decrease rapidly under the water surface due to absorption of saturated sand to the electromagnetic (EM) waves. The GPR electromagnetic wave penetrates less than 5 m on modern beach because of the intrusion of salted sea water. The same phenomenon is encountered on the shoal near the lagoon where the ground water invades sediments. Several GPR facies can be identified from the profiles. As to Yudai Tan coastal bar, two types of reflector configurations of regional significance were verified up and down the water surface or unconformity in some places. Parallel to slightly wavy reflectors above water surface contrast with hummocky, chaotic, oblique and hyperbola reflectors below the water surface. The former reflectors may indicate homogeneous and fine to medium sand while the latter indicates an increase in the content of coarse sand and gravel. Discontinues, hummocky and chaotic reflectors identified on Nangang Cun shoal may indicate an alternation between sand and clay during deposition. The results show that the Nangang Cun shoal may develop in late Holocene period and before it joined the coastal bar, there was a lagoonal region separating them. It is indicated that GPR is a reliable, rapid, and economical method for high-resolution profiling of subsurface sediments in sandy gravel coastal zone. In order to increase the reliability, continuous geological logs from test holes, wells and outcrops are needed to interpret the radar data.

Key words: barrier-lagoon system, shoal, sedimentary sequence, GPR, reflector configuration, Bo’ao