Received date: 2001-12-17
Revised date: 2002-03-06
Online published: 2002-05-25
Supported by
Project of the Cooperation between China and Canada, No. CCHEP282/19736
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
YIN Yong, ZHU Dakui, WANG Ying, GE Chendong, I. Peter Martini . On Barrier-Lagoon Development and GPR Application in BO'AO Area[J]. Acta Geographica Sinica, 2002 , 57(3) : 301 -309 . DOI: 10.11821/xb200203006
[1] Wang Ying et al. Tidal Inlet-embayment Coasts of Hainan Island. Beijing: China Environmental Science Press, 1998. 282.
[王颖 等著. 海南潮汐叉道港湾海岸. 北京: 中国环境科学出版社, 1998. 282.]
[2] Wang Wenjie. Sea level change and development course of barrier lagoons along coast of western Guangdong since middle Holocene. Tropical Oceanology, 1999, 18(3): 32-37.
[王文介. 粤西海岸全新世中期以来海平面升降与海岸沙坝泻湖发育过程. 热带海洋, 1999, 18(3): 32-37.]
[3] Gao Shanming, Li Yuanfang, Liu Guohai. Depositional characteristics of the system of sand-gravel outer bar and lagoon eustasy in Holocene in Liaoning coastal zone. Acta Geographica Sinica, 1992, 47(2): 129-137.
[高善明, 李元芳, 刘国海. 辽宁海岸沙砾堤-泻湖体系沉积特征与全新世海面变化. 地理学报, 1992, 47(2): 129-137.]
[4] Chen Xinshu. Geomorphology and development of Guangdong and Hainan sand coast. Tropical Oceanology, 1989, 8(1): 43-51.
[陈欣树. 广东和海南岛砂质海岸地貌及其开发利用. 热带海洋, 1989, 8(1): 43-51.]
[5] Li Guangzhao, Qi Faqing, Nong Huaqiong. Sedimentary facies sequences and evolutionary process of sedimentary environment of the barrier-lagoons in Jiangping area, Guangxi. Journal of Oceanography of Huanghai & Bohai Seas, 1999, 17(2): 8-18.
[倪广钊, 亓发庆, 农华琼 等. 广西江平地区沙坝-泻湖沉积相序与沉积环境演变过程. 黄渤海海洋, 1999, 17(2): 8-18.]
[6] Thom B G. Transgressive and regressive stratigraphy of coastal sand barriers in southeast Australia. Marine Geology, 1983, 56: 137-156.
[7] Li Jiansheng. The Quaternary environment evolution of the Leizhou Peninsula area, China. Marine Sciences, 1990, (2): 20-24.
[李建生. 华南沿海地区海相地层与全新世地层划分. 海洋科学, 1990, (2): 20-24.]
[8] Zhao Huanting, Zhang Qiaomin, Song Chaojing et al. Geomorphology and environment of the South China coast and the South China Sea Island. Beijing: Science Press, 1999. 528.
[赵焕庭, 张乔民, 宋朝景 等. 华南海岸和南海诸岛地貌与环境. 北京: 科学出版社, 1999. 528.]
[9] Luo Zhangren. Recent coastal landforms in Hainan Island. Tropical Geography, 1986, 7(1): 65-75.
[罗章仁. 海南岛现代海岸地貌. 热带地理, 1986, 7(1): 65-75.]
[10] Zhang Zhongying, Liu Ruihua. The Holocene along the coast of Hainan Island. Scientia Geographica Sinica, 1987, 7(2):129-139.
[张仲英, 刘瑞华. 海南岛沿海全新世. 地理科学, 1987, 7(2): 129-138. ]
[11] Chen Xidong, Fan Shiqing. Late Quaternary deposition and environment in the sea area northwest of Hainan Island.Tropical Geography, 1988, (1): 39-47.
[陈锡东, 范时清. 海南岛西北面海区晚第四纪沉积环境. 热带海洋, 1988, (1): 39-47.]
[12] Li Congxian, Wang Ping. Stratigraphy and distribution of Holocene barrier-lagoon system along China coast. Marine Science Bulletin, 1993, 12(3): 80-85.
[李从先, 王平. 我国沿岸全新世沙坝-泻湖体系的地层和分布. 海洋通报, 1993, 12(3): 80-85.]
[13] Van Dam L R, Schlager W. Identifying causes of ground-penetrating radar reflections using time-domain reflectometry and sedimentological analyses. Sedimentology, 2000, 47: 435-449.
[14] Stevens K M, Lodha G S, Holloway A L et al. The application of ground penetrating radar for mapping fractures in plutonic rocks within the Whiteshell research area, Pinawa, Manitoba, Canada. Journal of Applied Geophysics, 1995,33: 125-141.
[15] Sternberg Ben K, Mcgill J M. Archaeology studies in southern Arizona using ground penetrating radar. Journal of Applied Geophysics, 1995, 33: 209-225.
[16] Dolphin L T, Beatty W B, Tanzi J D. Radar probing of Victorio Peek, New Mexico. Geophysics, 1978, 43(7):1441-1448.
[17] Cook J C. Radar transparencies of mine and tunnel rocks. Geophysics, 40(5): 865-885.
[18] Tang Wenwu, Zhu Dakui, Ge Chendong et al. The application of ground penetrating radar to the survey of the coast environment. Marine Geology & Quaternary Geology, 2001, 21(2): 99-105.
[唐文武, 朱大奎, 葛晨东 等. 探地雷达 (GPR) 在海岸环境勘测中的应用. 海洋地质与第四纪地质, 2001, 21(2): 99-105.]
[19] Davis J L, Annan A P. Ground penetrating radar for high resolution mapping of soil and rock stratigraphy. Geophysical Prospecting, 1989, 37: 531-551.
[20] Vaughan C J. Ground-penetrating radar surveys used in archaeological investigations. Geophysics, 1986, 51(3): 595-604.
[21] Ferguson R J, Brierley G J. Levee morphology and sedimentology along the lower Tuross River, south-eastern Australia. Sedimentology, 1999, 46: 627-648.
[22] Beres M, Green A, Huggenberger P et al. Mapping the architecture of glaciofluvial sediments with three-dimensional georadar. Geology, 1995, 12: 1087-1090.
[23] Nicollin F, Kofman W. Ground penetrating radar sounding of a temperate glacier: modelling of a multilayered medium. Geophysical Prospecting, 1994, 42: 715-734.
[24] Beres M Jr., Haeni F P. Application of ground-penetrating-radar methods in hydrogeologic studies. Ground Water, 1991, 29: 375-386.
[25] Bridge N S, Alexander J, Collier R E et al. Ground-penetrating radar and coring used to study the merge-scale structure of point-bar deposits in three dimensions. Sedimentology, 1995, 42: 839-852.
[26] Smith D G, Jol H M. Radar structure of a Gilbert-type delta, Peyto Lake, Banff National Park, Canada. Sedimentary Geology, 1997, 113:195-209.
[27] Wu Zheng, Wu Kegang. Sedimentary structure and developing model of coastal dunes along the northeastern coast of Hainan Island, China. Acta Geographica Sinica, 1987, 42(2): 129-141.
[吴正, 吴克刚. 海南岛北部海岸沙丘的沉积构造特征及其发育模式. 地理学报, 1987, 42(2): 129-141.]
/
| 〈 |
|
〉 |