南极罗斯海重力场特征及莫霍面深度反演  

Regional characteristics and Moho depth for the Ross Sea, Antarctic

作　　者：马龙 郑彦鹏 Ma Long;Zheng Yanpeng(Key Laboratory of Marine Sedimentology and Environmental Geology,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;Key Laboratory of Marine Mineral Resources,Ministry of Natural Resources,Guangzhou 510075,China;Laboratory for Marine Geology,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266061,China)

机构地区：[1]自然资源部第一海洋研究所海洋沉积与环境地质重点实验室,山东青岛266061 [2]自然资源部海底矿产资源重点实验室,广东广州510075 [3]青岛海洋科学与技术试点国家实验室海洋地质过程与环境功能实验室,山东青岛266061

出　　处：《海洋学报》2020年第1期144-153,共10页

基　　金：自然资源部海底矿产资源重点实验室开放基金(KLMMR-2018-B-01);国家基金委-山东省联合基金项目(U1606401);泰山学者攀登计划(tspd20161007);极地科学战略研究基金(20120309);国家青年基金(41606084);南北极环境综合考察与评估专项(CHINARE2017-01-03-02,CHINARE2017-04-01-04)

摘　　要：本文基于中国南极考察第30航次、第32航次所获得的实测重力资料,结合NGDC资料,开展12个航次重力场数据的平差融合工作,全部386个交点平差后标准差减小为±1.53×10−5 m/s2,与卫星重力差值平均值为1.49×10−5 m/s2,均方差为±3.81×10−5 m/s2,并在此基础上采用频率域界面反演法计算莫霍面深度。研究发现,与沉积盆地对应重力异常低值相悖,在罗斯海北部盆地、维多利亚地盆地、中央海槽、东部盆地4个主要盆地腹地却表现为重力异常高值,跨度达100 km以上。莫霍面深度分布整体呈南深北浅之势,范围为10~28 km。伴随着罗斯海西部盆地的多次拉张及岩浆活动,该区域的地壳厚度和莫霍面深度高值和低值相间分布,并表现出越来越大的差异性。综合剖面结果表明,罗斯海重力异常值的长波长变化与莫霍面的起伏呈正相关关系,但是反演的莫霍面深度与区域重力场特征并非完全对应,所以岩浆底侵和地壳侵入仍不足以导致罗斯海盆地的重力异常或盆地几何形状。Based on the measured data in the 30 th, 32 th of Chinese National Antarctic Research Expedition, combined with the reference data, this study processed 12 groups of data in study area and draw the gravity anomaly map, with all 386 crossovers among these cruises the standard deviation reaching ±1.53×10-5 m/s2. Compared to satellite gravity, the mean value of the difference is 1.49×10-5 m/s2, with the standard deviation is ±3.81×10-5 m/s2.On this basis, we used a frequency domain interface inversion method to calculate the Moho depth. It is contrary to sedimentary basins with low values of gravity anomaly, the gravity of the hinterland in the northern Ross Basin, the Victoria Basin, the Central Trough and the Eastern Basin is high, with a span of 100 km or more. The distribution of the Moho depth is generally high in the south and low in the north, ranging from 10 km to 28 km. Along with the multiple extensions and magmatism in the western part of the Ross Sea, the crustal thickness and Moho depth of the area show increasing differences, with interphase distribution of abnormal high and low values. Combining inverted depth of Moho and Gravity-Seismic inversion interpretation profile, we considered the long-wavelength variation of the gravity anomaly is positively correlated with the fluctuation of the Moho depth. However, the inversion Moho depth does not correspond exactly to the regional gravity field characteristics, so magma underplating and crustal intrusion are still insufficient to cause gravity anomalies or basin geometries in the Ross Sea Basin.

关 键 词：重力场特征 莫霍面深度 罗斯海 南极 

分 类 号：P738.2[天文地球—海洋地质]