南极布兰斯菲尔德海峡船测重力资料处理及区域重力场特征

发布时间：2018-04-01 17:17

本文选题：布兰斯菲尔海峡　切入点：重力数据处理　出处：《国家海洋局第一海洋研究所》2015年硕士论文

【摘要】：南极大陆及周边海域是目前国际资源调查与环境变化研究的热点地区。通过海洋地球物理考察与评价,探测南极周围陆架上的地层分布特点,可以解译记录在地层中的以前南极环境变化的信息。海洋重力测量作为海洋地球物理调查的基本方法之一,对于研究南极周边海域的地质构造特征与演化,进而指导海域资源调查与全球变化研究等具有重要意义。我国自1984年首次在南极半岛布兰斯菲尔德海峡开展海洋重力调查以来,已先后开展了31个航次的南极考察,在南极半岛布兰斯菲尔德海峡、普利兹湾等海域积累了丰富的资料。然而,由于受海冰、风浪、定位精度等多重因素影响,且存在仪器类型不统一等问题,产生的偶然误差和系统误差相对较大。本论文基于我国在南极半岛布兰斯菲尔德海峡的实测数据,结合国际公开数据,依次采用精度控制、最小二乘平差、船测数据融合、重力场与构造分析等方法,总结出了一套适于极区海域船测重力数据处理的方法流程,研究显示:依次采用逐点分析、最小二乘滤波、交叉耦合改正分析及厄特渥斯改正值再校正等方法处理,可达到在数据处理过程中控制精度的目标。本论文利用研究区数据融合结果系统分析了南极布兰斯菲尔德海峡的重力场特征,基于改良的艾里模型,反演计算莫霍面的深度,并进行均衡改正获得均衡重力异常及均衡残余异常。结合收集的地震剖面资料分析了区域构造特征,研究表明:(1)布兰斯菲尔德海峡空间重力异常呈条带状分布,走向总体与地形相近,异常场被欺骗岛和布里奇曼岛分为3个区域,同时被北北西走向的构造线及海底火山隔开,在中部海槽形成多个异常低值圈闭。(2)海峡内的布格重力异常由两侧向中间为升高的异常,大致在坡折处形成异常场值为100×10-5m/s2的分界线,在中部次海槽和东部次海槽海山处形成两个异常高值圈闭,异常值最高为150×10-5m/s2。此外,在陆坡区形成多个圈闭异常。(3)布兰斯菲尔德海峡内海岛之间莫霍面深度的连续性被后期的海底火山活动和断裂构造隔断,与研究区南北分带,东西分块的构造格局相对应。莫霍面深度以弧后扩张中心为最低值,向南设得兰群岛和南极半岛两个方向递增,数值从12km递增至陆坡位置的24km。(4)布兰斯菲尔德海峡弧后扩张中心区域更趋于均衡平衡的状态。研究区中部次海槽均衡残余异常高值出现在海底火山位置,异常场主要以60×10-5m/s2为主。
[Abstract]:The Antarctic continent and its surrounding sea area are the hot spots in the international resource survey and environmental change research at present. By means of marine geophysical investigation and evaluation, the stratigraphic distribution characteristics of the continental shelf around the Antarctic are explored. As one of the basic methods of marine geophysical survey, marine gravimetry can be used to study the geological structure and evolution of the sea area around Antarctica. It is of great significance to guide the investigation of sea area resources and the study of global change. Since the first marine gravity survey in the Bran Strait of the Antarctic Peninsula in 1984, China has carried out 31 expeditions to the Antarctic. In the Bran Strait of the Antarctic Peninsula, Pritz Bay has accumulated abundant data. However, due to the influence of many factors, such as sea ice, wind and waves, positioning accuracy, and so on, there are many problems such as the disunity of instrument types and so on. The accidental error and the systematic error are relatively large. Based on the measured data of our country in the Bran Strait of the Antarctic Peninsula, combining with the international public data, the accuracy control, the least square adjustment, and the data fusion of the ship survey are adopted in turn. The method of gravity field and structure analysis is summarized, and a set of method flow of gravity data processing suitable for marine gravity survey in polar area is summarized. The results show that point by point analysis, least square filter, and so on are adopted in turn. Cross-coupling correction analysis and Ertworth correction correction, etc., In this paper, the gravity field characteristics of Bran Strait in Antarctica are systematically analyzed by using the data fusion results of the study area, and the depth of Moho surface is inversed based on the improved Eli model. The isostatic gravity anomaly and the isostatic residual anomaly are obtained by equalization correction. The regional structural characteristics are analyzed in combination with the collected seismic profile data. The results show that the spatial gravity anomaly of the Bran Strait is a strip distribution. The anomalous field is divided into 3 regions by deceiving island and Bridgman island, and is separated by the tectonic line of NNW strike and submarine volcano. The Bouguer gravity anomaly in the Central trough is elevated from two sides to the middle, and the boundary of anomaly field is about 100 脳 10-5m/s2 at the slope break. Two anomalous high value traps were formed at the middle subtrough and the eastern subtrough seamounts. The highest abnormal values were 150 脳 10 ~ (-5) m / s ~ (2). The continuity of the Moho depth between the islands in the Bran Strait is separated by late submarine volcanic activity and fault structures, and is separated from the north-south zone of the study area. The depth of Moho surface is the lowest in the center of back-arc expansion, and increases in the direction of south Shetland Islands and Antarctic Peninsula. The numerical value increases from 12km to 24km.m.4 of the continental slope) the region of the back-arc expansion center of the Bran Strait tends to be more balanced. In the central part of the study area, the residual anomaly of the subtrough equalization appears in the submarine volcanic position, and the main anomaly field is 60 脳 10-5m/s2.
【学位授予单位】：国家海洋局第一海洋研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P223.39

【参考文献】