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

doi:10.1002/ggge.20264

CORC > 北京大学 > 地球与空间科学学院

	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 ; Li, Jiabiao ; Sauter, Daniel ; Ruan, Aiguo ; Chen, John ; Cannat, Mathilde ; Singh, Satish ; Zhang, Jiazheng ; Wu, Zhenli ; Niu, Xiongwei
刊名	geochemistry geophysics geosystems
	2013
关键词	ultraslow spreading ridge 3-D seismic structure SW Indian Ridge oceanic core complex detachment fault MID-ATLANTIC RIDGE UPPER CRUSTAL STRUCTURE EAST PACIFIC RISE II FRACTURE-ZONE SEA-FLOOR HYDROTHERMAL FIELD THIN CRUST TOMOGRAPHY REFRACTION ACCRETION
DOI	10.1002/ggge.20264
英文摘要	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.; Geochemistry & Geophysics; SCI(E); EI; 4; ARTICLE; 10; 4544-4563; 14
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/220117]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Zhao, Minghui,Qiu, Xuelin,Li, Jiabiao,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.
APA	Zhao, Minghui.,Qiu, Xuelin.,Li, Jiabiao.,Sauter, Daniel.,Ruan, Aiguo.,...&Niu, Xiongwei.(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.
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 (2013).