摘要
全新世大暖期海侵边界的位置确定对研究区域古沉积环境演化和应对未来不确定的海平面上升对海岸带地区造成的影响提供了重要基础性前提.古海侵边界的确切位置可以通过追踪具有连续地层区域的海相地层尖灭点实现.本文选取莱州湾东岸具有钻孔数据和典型古海岸线地貌标志的区域为试验场,提出了一种探地雷达(GPR)追踪大暖期海侵边界的方法.结果显示,选取探测深度7—8m、图像分辨率0.3m的100MHz超强地面耦合(RTA)非屏蔽天线能够较好地识别海侵体系界面,结合已有钻孔Y61和现场探挖的浅钻,能够获得海侵沉积层由海向陆逐渐向上延伸、直至尖灭的层位位置变化信息的剖面图像.依据已确立的方法,在莱州湾南岸已有钻孔ZK305附近也取得了较好的效果.海侵形成的粉砂、细砂和泥的薄互层以楔形侵入至古今陆相沉积层间,在雷达图像上会形成明显的反射特征.方便快捷的探地雷达技术结合部分钻孔资料可用于海相层、古海岸线位置的精确测定,为古海岸线位置不确定的区域提供纵向直观、层序地层方面的判定依据.
Determination position of paleoshoreline in the Holocene Megathermal period can provide important reference for understanding the paleoenvironments evolution and coping with the future impact of uncertain sea-level rise on coastal zones. The determinate position of paleoshoreline can be discovered by tracking marine facies deposits pinch-out in continuous stratigraphic distribution. This problem motivated an integrated Groun the area with d Penetrating Radar（GPR） and sedimentological log data to identify the transgression boundary. Several GPR reflection lines had been collected between the dead cliff and Y61 driUing hole in eastern coast of Laizhou Bay with three different frequency antennas. The data from 100MHz RTA can resolve the internal architecture of the transgression system with a vertical resolution of about 0.3 m and effective penetration depth of 7--8m. It is feasible to image the architecture of different sedimentary units based on joint interpretation of the GPR reflections and sedimentological facies logs. From this map, the marine facies deposits pinch-out can been determined that is the position of paleoshoreline. In accordance with established methods, the change of transgression sedimentary layer near the ZK305 had been examined, and the pinch-out position had been identified accurately drilling hole in the southern Laizhou Bay. To conclusion, the interbedded transgression body with silt, sand and mud can be interpreted from the continental sedimentary layer. This method provides an illustrative judgment region with uncertainty transgression boundary. basis of sequence stratigraphy in some
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2014年第2期252-265,共14页
Journal of Basic Science and Engineering
基金
国家自然科学基金项目(41106041
41106036)
中国科学院战略性先导科技专项项目(XDA05120601)
中国科学院知识创新工程重要方向性项目(KZCX2-EW-207)
作者简介
通信作者：黄海军（1963-），男，研究员，博导．E-mail：hjhuang@qdio．ac．cn
刘艳霞（1979-），女，助研，博士．E—mail：liuyanxia@qdio．ac．cn
