南极南设得兰群岛海域地质新进展:“海洋六号”南极科考初步成果
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摘要
2016—2017年跨年度执行的中国第33次南极科考"海洋六号"航次,首次获取了南极半岛南设得兰群岛北部海域、布兰斯菲尔德海峡以及欺骗岛三个区域的17 850 km~2范围内多波束全覆盖高精度水深数据,地形分辨率高于目前公开的国际数据。多道地震结果显示调查区多处存在天然气水合物地球物理标志BSR。地热测量热流值表明南设得兰群岛以北热流值与全球海洋热流值数据吻合,不存在明显异常,群岛以南热流值数据偏高。沉积物样品为典型的冰海沉积物,在南设得兰群岛与南设得兰海沟之间,沉积物以粉砂-砂为主,夹杂砾石,随水深增加,沉积物粒径变细;而在布兰斯菲尔德海区表层沉积物分布具有不对称性,海槽南部陆架-上陆坡以及海槽东北和相邻陆架,沉积物以砾石、砂质为主;海槽和下陆坡为粉砂质硅质软泥。沉积物顶空气样品现场测试结果表明,表层沉积物50 cm左右深度内的甲烷含量没有明显的差异性,但在岛坡深水区两个测站甲烷含量在270cm左右深度时都存在局部高异常,且两者总甲烷含量的变化趋势有一定的相似性,可能与水合物分解迁移有关。
The 33 rd China Antarctic Research Expedition R/V "Hai Yang Liu Hao" Cruise, which was implemented in 2016–2017, was the first to obtain the full coverage and high precision multi-beam echo sounding water depth data of the seabed in the north of the South Shetland Islands, the Bransfield Strait and the Deception Island in the Antarctic Peninsula, covering an area of 17 850 km~2. Accurate topographic maps with higher terrain resolution than currently published data were obtained. The results of multi-channel seismic show that there are many natural gas hydrate geophysical markers BSR in the survey area. The geothermal heat flow value indicates that the heat flow value in the north of the South Shetland Islands is consistent with the global ocean heat flow data. There is no obvious anomaly, and the heat flux value data in the south of the archipelago are relatively high. Sediment samples are typical submarine glacial sediments between the South Shetland Islands and the South Shetland Trench. The sediments are dominated by silt-sand, mixed with gravel, and the sediment size becomes finer with increasing water depth. The distribution of surface sediments in the Bransfield Strait area is asymmetrical. On the southern shelf-upper slope of the trough and in the northeast and adjacent shelf of the trough, the sediments are mainly gravel and sandy, whereas the trough and the lower slope are silty siliceous ooze. The field test results of the headspace gases sample of sediments show that there is no significant difference in the methane content of surface sediments at the depth of about 50 cm below the seabed, but there are local high anomalies in the methane content of the two stations in the deep water area of the island slope at around 270 cm below the seabed. There is a certain similarity in the trend of total methane content, which may be caused by the decomposition and migration of hydrates.
The 33 rd China Antarctic Research Expedition R/V "Hai Yang Liu Hao" Cruise, which was implemented in 2016–2017, was the first to obtain the full coverage and high precision multi-beam echo sounding water depth data of the seabed in the north of the South Shetland Islands, the Bransfield Strait and the Deception Island in the Antarctic Peninsula, covering an area of 17 850 km~2. Accurate topographic maps with higher terrain resolution than currently published data were obtained. The results of multi-channel seismic show that there are many natural gas hydrate geophysical markers BSR in the survey area. The geothermal heat flow value indicates that the heat flow value in the north of the South Shetland Islands is consistent with the global ocean heat flow data. There is no obvious anomaly, and the heat flux value data in the south of the archipelago are relatively high. Sediment samples are typical submarine glacial sediments between the South Shetland Islands and the South Shetland Trench. The sediments are dominated by silt-sand, mixed with gravel, and the sediment size becomes finer with increasing water depth. The distribution of surface sediments in the Bransfield Strait area is asymmetrical. On the southern shelf-upper slope of the trough and in the northeast and adjacent shelf of the trough, the sediments are mainly gravel and sandy, whereas the trough and the lower slope are silty siliceous ooze. The field test results of the headspace gases sample of sediments show that there is no significant difference in the methane content of surface sediments at the depth of about 50 cm below the seabed, but there are local high anomalies in the methane content of the two stations in the deep water area of the island slope at around 270 cm below the seabed. There is a certain similarity in the trend of total methane content, which may be caused by the decomposition and migration of hydrates.
引文
陈玺,文鹏飞,付少英,何高文.2018a.基于LIFT思想的噪声压制技术在南极海域地震资料中的应用[J].地球学报,39(6):667-672.
陈玺,付少英,何高文,文鹏飞,杨力,刘斌.2018b.南极半岛附近海域与南海北部海域多道地震资料对比分析[J].地球学报,39(6):673-678.
王光宇,陈邦彦,张国祯,段威武,陈圣源.1996.南极布兰斯菲尔德海区地质[M].北京:地质出版社.
吴聪,王金莲,何高文,付少英,王力锋,赖佩欣.2018.南极乔治王岛与象岛邻近海域表层沉积硅藻组成及分布特征[J].地球学报,39(6):657-665.
中国地质科学院.2018.中国地质调查局、中国地质科学院2017年度地质科技十大进展发布[J].地球学报,39(2):129-131.
CHEN Xi,FU Shao-ying,HE Gao-wen,WEN Peng-fei,YANG Li,LIU Bin.2018b.An Comparative Analysis of Multichannel Seismic Data of the Sea Area near Antarctic Peninsula and Northern South China Sea[J].Acta Geoscientica Sinica,39(6):673-678(in Chinese with English abstract).
CHEN Xi,WEN Peng-fei,FU Shao-ying,HE Gao-wen.2018a.The Application of Noise Suppression Technology to Seismic Data of Antarctic Sea Area Based on LIFT[J].Acta Geoscientica Sinica,39(6):667-672(in Chinese with English abstract).
Chinese Academy of Geological Sciences.2018.Top Ten Geological Sci-tech Progresses of China Geological Survey(CGS)and Chinese Academy of Geological Sciences(CAGS)in the Year 2017 Unveiled[J].Acta Geoscientica Sinica,39(5):129-131(in Chinese).
GRACIA E,CANALS M,FARRAN M L,PIETO M J,SORRIBAS J,GEBRA TEAM.1996.Morphostructure and Evolution of the Central and Eastern Bransfield Basins(NWAntarctic Peninsula)[J].Marine Geophysical Researches,18(2-4):429-448.
JIN Y K,LEE J,HONG J K,NAM S H.2009.Is subduction ongoing in the South Shetland Trench,Antarctic Peninsula?:new constraints from crustal structures of outer trench wall[J].Geosciences Journal,13(1):59-67.
LODOLO E,CAMERLENGHI A,BRANCOLINI G.1993.A bottom Simulating reflector on the South Shetland margin,Antarctic Peninsula[J].Antarctic Sciences,5(2):207-210.
LODOLO E,CAMERLENGHI A,MADRUSSANI G,TINIVELLAU,ROSSI G.2002.Assessment of gas hydrate and free gas distribution on the South Shetland margin(Antarctica)based on multichannel seismic reflection data[J].Geophysical Journal International,148:103-119.
MALDONADO A,LARTER R D,ALDAYA F.1994.Fore-arc tectonic evolutions of the South Shetland margin,Antarctic Peninsula[J].Tectonics,13:1345-1370.
OLIVA URCIA B,GIL PENA I,MAESTRO A,LEZ MARTNEZ J,GALINDO ZALDVAR J,SOTO R,GIL IMAZ A,REY J,PUEYO O.2016.Paleomagnetism from Deception Island(South Shetlands archipelago,Antarctica),new insights into the interpretation of the volcanic evolution using a geomagnetic model[J].International Journal Earth Sciences,105:1-18.
PETERSEN S,HERZIG P M,SCHWARZ-SCHAMPERA U,HANNINGTON M D,JONASSON I R.2004.Hydrothermal precipitates associated with bimodal volcanism in the Central Bransfield Strait,Antarctica[J].Mineralium Deposita,39(3):358-379.
REY J,SOMOZA L,MARTINEZ-FRIAS J.1995.Tectonic,volcanic,and hydrothermal event sequence on Deception Island(Antarctica)[J].Geo-Marine Letters,15(1):1-8.
TINIVELLA U,ACCAINO F,CAMERLENGHI A.2002.Gas hydrate and free gas distribution form inversion of seismic data on the South Shetland margin(Antarctica)[J].Marine Geophysical Researches,23:109-123.
TINIVELLA U,ACCAINO F,DELLA VEDOVA B.2008.Gas hydrates and active mud volcanism on the South Shetland continental margin,Antarctic Peninsula[J].Geo-Marine Letters,28(2):97-106.
TINIVELLA U,ACCAINO F.2000.Compressional velocity structure and Poisson’s ratio in marine sediments with gas hydrate and free gas by inversion of reflected and refracted seismic data(South Shetland Islands,Antarctica)[J].Marine Geology,164(1):13-27.
WANG Guang-yu,CHEN Bang-yan,ZHANG Guo-zhen,DUANWei-wu,CHEN Sheng-yuan.1996.Geology of Shetland Islands,Antarctic[M].Beijing:Geological Publishing House(in Chinese).
WU Cong,WANG Jin-lian,HE Gao-wen,FU Shao-ying,WANGLi-feng,LAI Pei-xin.2018.Distribution of Diatom Assemblages in the Surface Sediments near the King George Island and Elephant Island,Antarctica[J].Acta Geoscientica Sinica,39(6):657-665(in Chinese with English abstract).
ZELT C A,SMITH R B.1992.Seismic traveltime inversion for2-D crustal velocity structure[J].Geophysical Journal International,108(1):16-34.
陈玺,付少英,何高文,文鹏飞,杨力,刘斌.2018b.南极半岛附近海域与南海北部海域多道地震资料对比分析[J].地球学报,39(6):673-678.
王光宇,陈邦彦,张国祯,段威武,陈圣源.1996.南极布兰斯菲尔德海区地质[M].北京:地质出版社.
吴聪,王金莲,何高文,付少英,王力锋,赖佩欣.2018.南极乔治王岛与象岛邻近海域表层沉积硅藻组成及分布特征[J].地球学报,39(6):657-665.
中国地质科学院.2018.中国地质调查局、中国地质科学院2017年度地质科技十大进展发布[J].地球学报,39(2):129-131.
CHEN Xi,FU Shao-ying,HE Gao-wen,WEN Peng-fei,YANG Li,LIU Bin.2018b.An Comparative Analysis of Multichannel Seismic Data of the Sea Area near Antarctic Peninsula and Northern South China Sea[J].Acta Geoscientica Sinica,39(6):673-678(in Chinese with English abstract).
CHEN Xi,WEN Peng-fei,FU Shao-ying,HE Gao-wen.2018a.The Application of Noise Suppression Technology to Seismic Data of Antarctic Sea Area Based on LIFT[J].Acta Geoscientica Sinica,39(6):667-672(in Chinese with English abstract).
Chinese Academy of Geological Sciences.2018.Top Ten Geological Sci-tech Progresses of China Geological Survey(CGS)and Chinese Academy of Geological Sciences(CAGS)in the Year 2017 Unveiled[J].Acta Geoscientica Sinica,39(5):129-131(in Chinese).
GRACIA E,CANALS M,FARRAN M L,PIETO M J,SORRIBAS J,GEBRA TEAM.1996.Morphostructure and Evolution of the Central and Eastern Bransfield Basins(NWAntarctic Peninsula)[J].Marine Geophysical Researches,18(2-4):429-448.
JIN Y K,LEE J,HONG J K,NAM S H.2009.Is subduction ongoing in the South Shetland Trench,Antarctic Peninsula?:new constraints from crustal structures of outer trench wall[J].Geosciences Journal,13(1):59-67.
LODOLO E,CAMERLENGHI A,BRANCOLINI G.1993.A bottom Simulating reflector on the South Shetland margin,Antarctic Peninsula[J].Antarctic Sciences,5(2):207-210.
LODOLO E,CAMERLENGHI A,MADRUSSANI G,TINIVELLAU,ROSSI G.2002.Assessment of gas hydrate and free gas distribution on the South Shetland margin(Antarctica)based on multichannel seismic reflection data[J].Geophysical Journal International,148:103-119.
MALDONADO A,LARTER R D,ALDAYA F.1994.Fore-arc tectonic evolutions of the South Shetland margin,Antarctic Peninsula[J].Tectonics,13:1345-1370.
OLIVA URCIA B,GIL PENA I,MAESTRO A,LEZ MARTNEZ J,GALINDO ZALDVAR J,SOTO R,GIL IMAZ A,REY J,PUEYO O.2016.Paleomagnetism from Deception Island(South Shetlands archipelago,Antarctica),new insights into the interpretation of the volcanic evolution using a geomagnetic model[J].International Journal Earth Sciences,105:1-18.
PETERSEN S,HERZIG P M,SCHWARZ-SCHAMPERA U,HANNINGTON M D,JONASSON I R.2004.Hydrothermal precipitates associated with bimodal volcanism in the Central Bransfield Strait,Antarctica[J].Mineralium Deposita,39(3):358-379.
REY J,SOMOZA L,MARTINEZ-FRIAS J.1995.Tectonic,volcanic,and hydrothermal event sequence on Deception Island(Antarctica)[J].Geo-Marine Letters,15(1):1-8.
TINIVELLA U,ACCAINO F,CAMERLENGHI A.2002.Gas hydrate and free gas distribution form inversion of seismic data on the South Shetland margin(Antarctica)[J].Marine Geophysical Researches,23:109-123.
TINIVELLA U,ACCAINO F,DELLA VEDOVA B.2008.Gas hydrates and active mud volcanism on the South Shetland continental margin,Antarctic Peninsula[J].Geo-Marine Letters,28(2):97-106.
TINIVELLA U,ACCAINO F.2000.Compressional velocity structure and Poisson’s ratio in marine sediments with gas hydrate and free gas by inversion of reflected and refracted seismic data(South Shetland Islands,Antarctica)[J].Marine Geology,164(1):13-27.
WANG Guang-yu,CHEN Bang-yan,ZHANG Guo-zhen,DUANWei-wu,CHEN Sheng-yuan.1996.Geology of Shetland Islands,Antarctic[M].Beijing:Geological Publishing House(in Chinese).
WU Cong,WANG Jin-lian,HE Gao-wen,FU Shao-ying,WANGLi-feng,LAI Pei-xin.2018.Distribution of Diatom Assemblages in the Surface Sediments near the King George Island and Elephant Island,Antarctica[J].Acta Geoscientica Sinica,39(6):657-665(in Chinese with English abstract).
ZELT C A,SMITH R B.1992.Seismic traveltime inversion for2-D crustal velocity structure[J].Geophysical Journal International,108(1):16-34.