| 摘要: |
| 南极布兰斯菲尔德海峡及邻区是南极半岛海域火山、地震等新构造运动最活跃的地区，由于前人对资料处理解释的差异，导致盆地的构造格局仍部分存疑。本文以研究区的卫星重力数据为基础，以多道反射地震和部分岩性资料为约束，采用重震联合反演方法构建了三条横跨研究区的地壳结构剖面，并进一步研究布兰斯菲尔德海峡盆地的地壳结构。研究结果表明布兰斯菲尔德海峡盆地莫霍面深度为33-38km。菲尼克斯板块俯冲消减下沉至南设得兰岛弧之下，导致南设得兰海沟的俯冲带后撤，产生3-4km厚的岩浆混染地壳，密度为2.9g/cm3。分析认为受板块运动和弧后扩张影响，沿布兰斯菲尔德海峡盆地扩张脊分布的海底火山裂隙式喷发，并进一步导致盆地的持续性扩张。 |
| 关键词: 布兰斯菲尔德海峡 重震联合反演 地壳结构 扩张脊 |
| DOI：10.11693/hyhz20191000192 |
| 分类号:P738 |
| 基金项目:自然资源部海底矿产资源重点实验室开放基金，KLMMR-2018-B-01号；国家基金委-山东省联合基金项目，U1606401号；泰山学者攀登计划，TSPD20161007号。 |
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| STRUCTURE INVERSION AND ITS TECTONIC INTERPRETATION IN BRANSFIELD STRAIT AND THE ADJACENT AREA, ANTARCTIC |
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MA Long1,2,3, XING Jian4
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1.First Institute of Oceanography, MNR, Key Laboratory of Marine Sedimentology and Environmental Geology, Qingdao 266061, China;2.Key Laboratory of Marine Mineral Resources, Ministry of Natural Resources, Guangzhou 510075, China;3.Laboratory for Marine Geology, Pilot National Oceanography Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China;4.East Sea Marine Environmental Investigating & Surveying Center, SOA, Shanghai 200137, China
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| Abstract: |
| The Bransfield Strait, Antarctic, and the adjacent areas are the most active neotectonics region of volcanoes and earthquakes. Due to the differences in interpretation of data by former researchers, the structural pattern of the basin is still partially questionable. Based on the satellite gravity data, multi-channel reflection seismic and parts of the lithology data, we used gravity modeling to establish three crustal structure profiles across the basin, and analyzed the crustal structure. Results show that the Moho depth of the Bransfield Basin is 33-38km. The Phoenix Plate submerged and sank below the South Shetland Islands, causing the South Shetland trench subduction zone to retreat, producing a 3-4 km thick magma-contaminated crust in density of 2.9 g/cm3. The analysis suggests that under the influence of plate movement and back-arc spreading, the submarine volcanic fissure eruption along the spreading ridge of the Bransfield Basin leads to a further continued spreading of the basin. |
| Key words: Bransfield Strait gravity modeling crustal structure spreading ridge |
