基于探地雷达与光释光测年的广东海岸沙丘发育过程研究

The development of coastal dune are affected by multiple factors such as sand sources, wind strength and direction , sea level change, human activities, etc,. Its activation, fixing and reactivation are recorded in the internal stratification and physical and chemistry property of sand. It is suggested that the “Holocene Coastal Dunes” in Southern China were formed in the Mid-Holocene. However, their evolution and controlling factors of the coastal dune in Guangdong are still unclear. Here, we plan to study nine coastal dunes in Guangdong Province which have different types. The ground-penetrating radar (GPR) will be applied to achieve the 3-dimention GPR profiles for the dunes, which can be used to confirm the position of optically stimulated luminescence (OSL) dating samples. As a result, continuous 3D GPR images of the coastal dunes with accurate OSL ages will be synthesized. By this study, the evolution of the coastal dunes during the last 1000 years will be distinguished. The mechanism of the development of different coastal dunes in Guangdong since the Mid-Holocene will be discussed, including the effects of summer monsoon, winter monsoon, sea level changes, storm and human activities. The results will provided scientific basis for coastal land use in this region.

海岸沙丘的发育过程受沙源、风况、海平面升降以及人为活动等因素的控制，其运动、固定与再运动等信息都保留在丰富的内部层理与沙物质中。华南全新世海岸沙丘被普遍认为形成于中全新世以来。然而，晚全新世以来广东海岸沙丘的形成演化及控制因素至今尚不清楚。申请者近两年对粤东惠来与粤西湛江东海岛对海岸沙丘进行了初步的勘察与样品采集，在此基础上，拟对广东9个海岸沙丘区不同类型的海岸沙丘进行探地雷达勘察，合成反映海岸沙丘内部结构的连续的三维探地雷达剖面，读取采集光释光测年样品的最佳位置，获取光释光样品年代，合成附有光释光年代的高精度的连续的海岸沙丘三维雷达图像。在此基础上确认最近1000年以来广东海岸是否存在大规模的风沙堆积期，并探讨中全新世以来广东不同类型的海岸沙丘的发育过程及其与夏季风、冬季风、海平面变化、风暴、 人为活动等影响因素之间的关系，为当前海岸带开发建设等提供科学依据。