Three-dimensional seismic structure of the Dragon Flag oceanic core complex at the ultraslow spreading Southwest Indian Ridge (49 degrees 39 ' E)

CORC > 南海海洋研究所 > 中国科学院南海海洋研究所 > 中科院边缘海地质重点实验室

	Three-dimensional seismic structure of the Dragon Flag oceanic core complex at the ultraslow spreading Southwest Indian Ridge (49 degrees 39 ' E)
	[Zhao, Minghui ; Qiu, Xuelin ; Zhang, Jiazheng] Chinese Acad Sci, Key Lab Marginal Sea Geol, South China Sea Inst Oceanol, Guangzhou 510301, Guangdong, Peoples R China ; [Li, Jiabiao ; Ruan, Aiguo ; Wu, Zhenli ; Niu, Xiongwei] State Ocean Adm, Inst Oceanog 2, Hangzhou 310012, Zhejiang, Peoples R China ; [Sauter, Daniel] CNRS, UMR 7516, Inst Phys Globe Strasbourg, Strasbourg, France ; [Chen, John] Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China ; [Cannat, Mathilde ; Singh, Satish] Inst Phys Globe Paris, Lab Geosci Marine, Paris, France ; [Zhang, Jiazheng] Univ Chinese Acad Sci, Beijing, Peoples R China
刊名	GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
	2013
卷号	14 期号:10 页码:4544-4563
关键词	ultraslow spreading ridge 3-D seismic structure SW Indian Ridge oceanic core complex detachment fault
ISSN号	1525-2027
通讯作者	mhzhao@scsio.ac.cn ; jbli@sio.org.cn
中文摘要	The Southwest Indian Ridge (SWIR) is an ultraslow spreading end-member of mid-ocean ridge system. We use air gun shooting data recorded by ocean bottom seismometers (OBS) and multibeam bathymetry to obtain a detailed three-dimensional (3-D) P wave tomographic model centered at 49 degrees 39'E near the active hydrothermal "Dragon Flag'' vent. Results are presented in the form of a 3-D seismic traveltime inversion over the center and both ends of a ridge segment. We show that the crustal thickness, defined as the depth to the 7 km/s isovelocity contour, decreases systematically from the center (similar to 7.0-8.0 km) toward the segment ends (similar to 3.0-4.0 km). This variation is dominantly controlled by thickness changes in the lower crustal layer. We interpret this variation as due to focusing of the magmatic activity at the segment center. The across-axis velocity model documents a strong asymmetrical structure involving oceanic detachment faulting. A locally corrugated oceanic core complex (Dragon Flag OCC) on the southern ridge flank is characterized by high shallow crustal velocities and a strong vertical velocity gradient. We infer that this OCC may be predominantly made of gabbros. We suggest that detachment faulting is a prominent process of slow spreading oceanic crust accretion even in magmatically robust ridge sections. Hydrothermal activity at the Dragon Flag vents is located next to the detachment fault termination. We infer that the detachment fault system provides a pathway for hydrothermal convection.
学科主题	Geochemistry & Geophysics
资助信息	We are highly appreciated the scientists and the crew of DY115-21 cruise on board R/V Dayang Yihao. We are equally thankful for the discussions with Jian Lin, Henry Dick, and Huaiyang Zhou. This research was supported by funds from Chinese National Natural Science Foundation (41176053, 41076029, 91028002, 41176046) and DY115 (DYXM-115-02-3-01). M. Zhao was supported by IPGP for one month of cooperative research with S. Singh. The manuscript was improved by constructive reviews from Brian Tucholke, Ingo Grevemeyer, and Juan Pablo Canales.
原文出处	AMER GEOPHYSICAL UNION
语种	英语
WOS记录号	WOS:000330531400038
公开日期	2015-01-22
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/11111]
专题	南海海洋研究所_中科院边缘海地质重点实验室
推荐引用方式 GB/T 7714	[Zhao, Minghui,Qiu, Xuelin,Zhang, Jiazheng] Chinese Acad Sci, Key Lab Marginal Sea Geol, South China Sea Inst Oceanol, Guangzhou 510301, Guangdong, Peoples R China,et al. Three-dimensional seismic structure of the Dragon Flag oceanic core complex at the ultraslow spreading Southwest Indian Ridge (49 degrees 39 ' E)[J]. GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,2013,14(10):4544-4563.
APA	[Zhao, Minghui.,Qiu, Xuelin.,Zhang, Jiazheng] Chinese Acad Sci, Key Lab Marginal Sea Geol, South China Sea Inst Oceanol, Guangzhou 510301, Guangdong, Peoples R China.,[Li, Jiabiao.,Ruan, Aiguo.,...&[Zhang, Jiazheng] Univ Chinese Acad Sci, Beijing, Peoples R China.(2013).Three-dimensional seismic structure of the Dragon Flag oceanic core complex at the ultraslow spreading Southwest Indian Ridge (49 degrees 39 ' E).GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,14(10),4544-4563.
MLA	[Zhao, Minghui,et al."Three-dimensional seismic structure of the Dragon Flag oceanic core complex at the ultraslow spreading Southwest Indian Ridge (49 degrees 39 ' E)".GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS 14.10(2013):4544-4563.