检索结果-南通市图书馆

Crustal Structure across the Northwestern Margin of South China Sea:Evidence for Magma-poor Rifting from a Wide-angle Seismic Profile

引用

Acta Geologica Sinica(English Edition) 2012年第4期86卷 854-866页

作者： DING Weiwei Michael SCHNABEL Dieter FRANKE ruan aiguo WU Zhenli The Second Institute of Oceanography State Oceanic Administration Federal Institute for Geoscience and Natural Resource(BGR)

We present results from a 484 km wide-angle seismic profilie acquired in the northwest part of the South China Sea （SCS） during OBS2006 cruise. The line that runs along a previously acquired multi-channel seismic line （SO49-18） crosses the continental slope of the northern margin, the Northwest Subbasin （NWSB） of the South China Sea, the Zhongsha Massif and partly the oceanic basin of the South China Sea. Seismic sections recorded on 13 ocean-bottom seismometers were used to identify refracted phases from the crustal layer and also reflected phases from the crust-mantle boundary （Moho）. Inversion of the traveltimes using a simple start model reveals crustal images in the study area. The velocity model shows that crustal thickness below the continental slope is between 14 and 23 kin. The continental part of the line is characterized by gentle landward mantle uplift and an abrupt oeeanward one. The velocities in the lower crust do not exceed 6.9 km/s. With the new data we can exclude a high-velocity lower crustal body （velocities above 7.0 kin/s） at the location of the line. We conclude that this part of the South China Sea margin developed by a magma-poor rifting. Both, the NWSB and the Southwest Sub-basin （SWSB） reveal velocities typical for oceanic crust with crustal thickness between 5 and 7 kin. The Zhongsha Massif in between is extremely stretched with only 6-10 km continental crust left. Crustal velocity is below 6.5 kin/s; possibly indicating the absence of the lower crust. Multi-channel seismic profile shows that the Yitongansha Uplift in the slope area and the Zhongsha Massif are only mildly deformed. We considered them as rigid continent blocks which acted as rift shoulders of the main rift subsequently resulting in the formation of the Northwest Sub-basin. The extension was mainly accommodated by a ductile lower crustal flows, which might have been extremely attenuated and flow into the oceanic basin during the spreading stage. We compared the crustal stru

关键词： P-wave velocity model magma-poor rifting lower crust flow South China Sea

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Seismic phases from the Moho and its implication on the ultraslow spreading ridge

引用

Acta Oceanologica Sinica 2013年第12期32卷 75-86页

作者： ZHANG Jiazheng ZHAO Minghui QIU Xuelin LI Jiabiao ruan aiguo Key Laboratory of Marginal Sea Geology of Chinese Academy of Sciences South China Sea Institute of OceanologyChinese Academy of Sciences University of Academy of Sciences The Second Institute of Oceanography State Oceanic Administration

The Moho interface provides critical evidence for crustal thickness and the mode of oceanic crust accretion. The seismic Moho interface has not been identified yet at the magma-rich segments （46°-52°E） of the ultra- slow spreading Southwestern Indian Ridge （SWIR）. This paper firstly deduces the characteristics and do- mains of seismic phases based on a theoretical oceanic crust model. Then, topographic correction is carried out for the OBS record sections along Profile Y3Y4 using the latest OBS data acquired from the detailed 3D seismic survey at the SWIR in 2010. Seismic phases are identified and analyzed, especially for the reflected and refracted seismic phases from the Moho. A 2D crustal model is finally established using the ray tracing and travel-time simulation method. The presence of reflected seismic phases at Segment 28 shows that the crustal rocks have been separated from the mantle by cooling and the Moho interface has already formed at zero age. The 2D seismic velocity structure across the axis of Segment 28 indicates that detachment faults play a key role during the processes of asymmetric oceanic crust accretion.

关键词： Moho interface seismic phases ultra-slow spreading ridge 2D crustal structure SouthwesternIndian Ridge (SWIR)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Inversion of teleseismic waves at Shidao Seismographic Station

引用

Acta Oceanologica Sinica 2006年第5期25卷 63-73页

作者： ruan aiguo LI Jiabiao HAO Tianyao WU Qingju XU Yi Key Laboratory of Submarine C eosciences of State Oceanic Administration Hangzhou 310012 China Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100101 China Institute of Geophysics China Seismological Bureau Beijing 100081 China

Teleseismic datasets at the Shidao Seismographic Station, located in the northwestern South China Sea, are used to determine the earth anisotropy and the vertical distribution pattern of the shear wave velocity by inversion approaches. The rotated correction function is applied to analyzing high quality SeS records from five earthquakes at distance of 25°-35° to obtain shear wave splitting parameters of the lithosphere. The result from the deepest earthquake among the five events indicates that the polarization of the fast shear wave is N94°E, which means the direction of extensional stress or the moving of the upper mantle mass in Xisha Islands is nearly west to east and confirms that the crust in this region is a transitional one and the driving force beneath the crust is from the moving mass consistent with the Eurasian plate. The anisotropy effective thickness is estimated about 100 km based on the time delay of 1.3 s between the fast and slow shear waves. The receiver function is applied to analyzing high quality P wave records from nine earthquakes at distance of 20°- 60° to obtain the vertical distribution pattern of shear wave velocity beneath the station. The result indicates that the crust could be divided into three layers： the uppermost crust （5 km above） is a velocity gradient zone consisting of several small layers, where the shear wave velocity increases from 1.5 to 3.5 km/s gradually; the 5 - 16 km depth interval also consiss of several small layers of which the mean velocity is about 3.8 km/s; and the lower crust （ 16.0 - 26. 5 km） is an obvious low velocity layer with a velocity of about 3.6 km/s. The buried depth of the Moho discontinuity is 26.5 kin, the mean velocity of the layers beneath the Moho is about 4.7 km/s and there is an obvious low velocity layer just beneath the Moho. Moreover, analysis of the arrival time of converted waves and the swinging variation of velocity around the initial model suggests that smaller layers in the model mayb

关键词： South China Sea S wave splitting receiver function S wave velocity structure waveform inversion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Passive seismic experiment and ScS wave splitting in the southwestern subbasin of South China Sea

引用

Chinese Science Bulletin 2012年第25期57卷 3381-3390页

作者： ruan aiguo LI JiaBiao LEE ChaoShing QIU XueLin PAN ShaoJun The Second Institute of Oceanography State Oceanic AdministrationHangzhou 310012China Institute of Applied Geosciences Taiwan Ocean UniversityKeelung 20224China South China Sea Institute of Oceanology Chinese Academy of SciencesGuangzhou 510301China

The seismic experiment of 3D array of OBS in the southwestern sub-basin of the South China Sea(SCS) is briefly introduced in this *** data analysis of broadband OBS shows that totally 93 earthquakes with magnitude of Ms 6.0-6.9 and 10 earthquakes with magnitude above Ms 7.0 were recorded in high quality during this experiment,especially the catastrophic earthquake Ms 9.0 occurred in the east sea area of Japan on March 11,*** anisotropy parameters inversion of ScS wave of four events above Ms 7.0 indicates that the fast direction of shear wave is N58°E parallel to the ceased spreading ridge of the southwestern sub-basin of SCS(the slow direction is S35°E perpendicular to the spreading ridge),which means the spreading ridge is under compressing stress at present and the cessation of seafloor spreading is related to such stress field as well.

关键词：地震实验中国南海西南海盆分裂三维数组数据分析参数反演各向异性

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Crustal structure and variation along the southern part of the Kyushu-Palau Ridge

引用

Acta Oceanologica Sinica 2022年第1期41卷 50-57页

作者： Xiaodong Wei Weiwei Ding aiguo ruan Jie Zhang Xiongwei Niu Jiabiao Li Yong Tang Key Laboratory of Submarine Geosciences Ministry of Natural Resources/Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200240China

As an interoceanic arc,the Kyushu-Palau Ridge(KPR)is an exceptional place to study the subduction process and related magmatism through its interior velocity ***,the crustal structure and its nature of the KPR,especially the southern part with limited seismic data,are still in *** order to unveil the crustal structure of the southern part of the KPR,this study uses deep reflection/refraction seismic data recorded by 24 ocean bottom seismometers to reconstruct a detailed P-wave velocity model along the *** show strong alongridge variations either on the crustal velocity or the thickness of the KPR.P-wave velocity model is featured with(1)a crustal thickness between 6–12 km,with velocity increases from 4.0 km/s to 7.0 km/s from top to bottom;(2)high gradient(~1 s^(-1))in the upper crust but low one(<0.2 s^(-1))in the lower crust;(3)a slow mantle velocity between 7.2 km/s and 7.6 km/s in the uppermost mantle;and(4)inhomogenous velocity anomalies in the lower crust beneath *** comparing with the mature arc in the Izu-Bonin-Mariana arc in the east,this study suggests the southern part of KPR is a thicken oceanic crust rather than a typical arc *** origin of low velocities in the lower crust and upper mantle may be related with crustal differentiation,which implies advanced crustal evolution from normal oceanic crust to partly thicken oceanic *** velocities in the lower crust are related to the difference in magmatism.

关键词： P-wave velocity structure ocean bottom seismometer Kyushu-Palau Ridge magmatism thicken oceanic crust

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The morphotectonics and its evolutionary dynamics of the central Southwest Indian Ridge (49° to 51°E)

引用

Acta Oceanologica Sinica 2013年第12期32卷 87-95页

作者： LIANG Yuyang LI Jiabiao LI Shoujun ruan aiguo NI Jianyu YU Zhiteng ZHU Lei Institute of Oceanology Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Submarine Geosciences the Second Institute of OceanographyState Oceanic Administration China Ocean Mineral Resources Research and Development Association

The morphotectonic features and their evolution of the central Southwest Indian Ridge （SWIR） are dis- cussed on the base of the high-resolution flfll-coverage bathyraetric data on the ridge between 49°-51°E. A comparative analysis of the topographic features of the axial and flank area indicates that the axial topogra- phy is alternated by the ridge and trough with en echelon pattern and evolved under a spatial-temporal mi- gration especially in 49°-50.17°E. It is probably due to the undulation at the top of the mantle asthenosphere, which is propagating with the mantle flow. From 50.17° to 50.7°E, is a topographical high terrain with a crust much thicker than the global average of the oceanic crust thickness. Its origin should be independent of the spreading mechanism of ultra-slow spreading ridges. The large numbers of volcanoes in this area indicate robust magmatic activity and may be related to the Crozet hot spot according to RMBA （residual mantle Bouguer anomaly）. The different geomorphological feature between the north and south flanks of the ridge indicates an asymmetric spreading, and leading to the development of the OCC （oceanic core complex）. The tectonic activity of the south frank is stronger than the north and is favorable to develop the OCC. The first found active hydrothermal vent in the SWIR at 37°47＇S, 49°39＇E is thought to be associated with the detach- ment fault related to the OCC.

关键词： ultra-slow spreading multibeam bathymetry morphotectonics oceanic core complex,Southwest Indian Ridge

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The deep structure of the Duanqiao hydrothermal field at the Southwest Indian Ridge

引用

Acta Oceanologica Sinica 2018年第3期37卷 73-79页

作者： SUN Chaofeng WU Zhaocai TAO Chunhui ruan aiguo ZHANG Guoyin GUO Zhikui HUANG Enxian Key Laboratory of Submarine Geosciences State Oceanic AdministrationHangzhou 310012China Second Institute of Oceanography State Oceanic AdministrationHangzhou 310012China Institute of Geophysics and Geomatics China University of OceanographyWuhan 430074China Henan Province Earthquake Administration Zhengzhou 450016China

Polymetalic sulfide is the main product of sea-floor hydrothermal venting, and has become an important sea-floor mineral resources for its rich in many kinds of precious metal elements. Since 2007, a number of investigations have been carried out by the China Ocean Mineral Resources Research and Development Association（COMRA）cruises（CCCs） along the Southwest Indian Ridge（SWIR）. In 2011, the COMRA signed an exploration contract of sea-floor polymetallic sulfides of 10 000 km2 on the SWIR with the International Seabed Authority. Based on the multibeam data and shipborne gravity data obtained in 2010 by the R/V Dayang Yihao during the leg 6 of CCCs21, together with the global satellite surveys, the characteristics of gravity anomalies are analyzed in the Duanqiao hydrothermal field（37°39′S, 50°24′E）. The ＂subarea calibration＂ terrain-correcting method is employed to calculate the Bouguer gravity anomaly, and the ocean bottom seismometer（OBS） profile is used to constrain the two-dimensional gravity anomaly simulation. The absent Moho in a previous seismic model is also *** results show that the crustal thickness varies between 3 and 10 km along the profile, and the maximum crustal thickness reaches up to 10 km in the Duanqiao hydrothermal field with an average of 7.5 km. It is by far the most thicker crust discovered along the SWIR. The calculated crust thickness at the Longqi hydrothermal field is approximately 3 km, 1 km less than that indicated by seismic models, possibly due to the outcome of an oceanic core complex（OCC）.

关键词： crustal thickness Duanqiao hydrothermal field gravity anomaly polymetallic sulfides Southwest Indian Ridge

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Cenozoic tectono-sedimentary characteristics and extension model of the Northwest Sub-basin,South China Sea

引用

Geoscience Frontiers 2011年第4期2卷 509-517页

作者： Weiwei Ding Mingbi Li Lihong Zhao aiguo ruan Zhenli Wu Key Laboratory of the Submarine Geoscience State Oceanic Administration 32# North Baochu Road Hangzhou 310012 China Shandong University of Science and Technology Qingdao 266510 China

Based on the interpretations of three seismic profiles and one wide-angle seismic profile across the Northwest Sub-basin,South China *** sequences,deformation characteristics and an extension model for this sub-basin have been worked *** tectonic-stratigraphic units are *** analyses of extension show that the event occurred mainly during the Paleogene and resulted in the formation of half-grabens or grabens distributed symmetrically around the spreading *** are characterized by chaotic and discontinuous reflectors,indicating clastic sediments. Farther to the southwest,the sub-basin features mainly continental rifting instead of sea-floor spreading. The rifting would have been controlled by the shape of the massif and developed just along the northern edge of the Zhongsha-Xisha Block,rather than joined the Xisha *** 25 Ma.a southward ridge jump triggered the opening of the Southwest *** NW-directed stress caused by the sea-floor spreading of the Northwest Sub-basin may have prevented the continuous opening of the *** that the Northwest Sub-basin experienced thermal cooling and exhibited broad *** deep crustal structure shown by the velocity model from a wide-angle seismic profile is also symmetrical around the spreading center,which indicates that the Northwest Sub-basin might have opened in a pure shear model.

关键词： Continental rifting Cenozoic Tectono-sedimentary characteristics Extension model Northwest Sub-basin Marginal sea

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Oceanic crustal structure and tectonic origin of the southern Kyushu-Palau Ridge in the Philippine Sea

引用

Acta Oceanologica Sinica 2022年第1期41卷 39-49页

作者： Xiongwei Niu Pingchuan Tan Weiwei Ding Wei Wang Yao Wei Xiaodong Wei aiguo ruan Jie Zhang Chunyang Wang Yong Tang Jiabiao Li Key Laboratory of Submarine Geosciences Ministry of Natural Resources/Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200240China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China

A new high-resolution velocity model of the southern Kyushu-Palau Ridge(KPR) was derived from an activesource wide-angle seismic reflection/refraction profile. The result shows that the KPR crust can be divided into the upper crust with the P-wave velocity less than 6.1 m/s, and lower crust with P-wave velocity between 6.1 km/s and 7.2 km/s. The crustal thickness of the KPR reaches 12.0 km in the center, which gradually decreases to 5.0–6.0 km at sides. The velocity structure of the KPR is similar to the structures of the adjacent West Philippine Basin and Parece Vela Basin(PVB), indicating a typical oceanic crust. Isostatic analysis shows that some regional compensation occurs during the loading of the KPR, which implies that the KPR was built mainly by magmatism during the splitting of the Izu-Bonin-Mariana arc and the following back-arc seafloor spreading of the PVB during30–28 Ma BP. The absence of the thick middle crust(6.0–6.5 km/s) and high velocity lower-crustal layers(7.2–7.6 km/s) suggest that arc magmatism plays a less important role in the KPR formation.

关键词： P-wave crustal structure ocean bottom seismometer Kyushu-Palau Ridge oceanic crust

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Time correction of the ocean bottom seismometers deployed at the southwest Indian ridge using ambient noise cross-correlation

引用

Acta Oceanologica Sinica 2018年第5期37卷 39-46页

作者： LIU Yunlong LIU Cai TAO Chunhui YAO Huajian QIU Lei WANG Ao ruan aiguo WANG Hanchuang ZHOU Jianping LI Huaiming DONG Chuanwan College of Geoexploration Science and Technology Jilin University Key Laboratory of Submarine Geosciences Second Institute of OceanographyState Oceanic Administration Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space Sciences University of Science and Technology of China Institute of Geophysics and Geomatics China University of Geosciences School of Earth Sciences Zhejiang University

Seismic monitoring using ocean bottom seismometers（OBS） is an efficient method for investigating earthquakes in mid-ocean ridge far away from land. Clock synchronization among the OBSs is difficult without direct communication because electromagnetic signals cannot propagate efficiently in water. Time correction can be estimated through global positioning system（GPS） synchronization if clock drift is linear before and after the deployment. However, some OBSs in the experiments at the southwest Indian ridge（SWIR） on the Chinese DY125-34 cruise had not been re-synchronized from GPS after recovery. So we attempted to estimate clock drift between each station pairs using time symmetry analysis（TSA） based on ambient noise cross-correlation. We tested the feasibility of the TSA method by analyzing daily noise cross-correlation functions（NCFs） that extract from the data of another OBS experiment on the Chinese DY125-40 cruise with known clock drift and the same deployment site. The results suggest that the NCFs＇ travel time of surface wave between any two stations are symmetrical and have an opposite growing direction with the date. The influence of different band-pass filters,different components and different normalized methods was discussed. The TSA method appeared to be optimal for the hydrophone data within the period band of 2–5 s in dozens of km-scale interstation distances. A significant clock drift of ~2 s was estimated between OBSs sets through linear regression during a 108-d deployment on the Chinese cruise DY125-34. Time correction of the OBS by the ambient noise cross-correlation was demonstrated as a practical approach with the appropriate parameters in case of no GPS re-synchronization.

关键词： clock drift cross-correlation ambient noise OBS

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：