Evidence of an axial magma chamber beneath the ultraslow-spreading   Southwest Indian Ridge

doi:10.1130/G38356.1

CORC > 北京大学 > 地球与空间科学学院

	Evidence of an axial magma chamber beneath the ultraslow-spreading Southwest Indian Ridge
	Jian, Hanchao ; Singh, Satish C. ; Chen, Yongshun John ; Li, Jiabiao
刊名	GEOLOGY
	2017
关键词	EAST PACIFIC RISE SEA-FLOOR GENERATION MID-ATLANTIC RIDGE SEISMIC EVIDENCE OCEANIC-CRUST STREAMER DATA MELT INJECTION INVERSION VOLCANO
DOI	10.1130/G38356.1
英文摘要	Ultraslow-spreading ridges are a novel class of spreading centers symbolized by amagmatic crustal accretion, exposing vast amounts of mantle-derived peridotites on the seafloor. However, distinct magmatic centers with high topographies and thick crusts are also observed within the deep axial valleys. This suggests that despite the low overall melt supply, the magmatic process interacting with the tectonic process should play an important role in crustal accretion; however, this has been obscured due to the lack of seismic images of magma chambers. Using a combination of seismic tomography and full waveform inversion of ocean bottom seismometer data from the Southwest Indian Ridge at 50 degrees 28'E, we report the presence of a large low-velocity anomaly (LVA) similar to 4-9 km below the seafloor, representing an axial magma chamber (AMC) in the lower crust. This suggests that the 9.5-km-thick crust here is mainly formed by a magmatic process. The LVA is overlain by a high-velocity layer, possibly forming the roof of the AMC and defining the base of hydrothermal circulation. The steep velocity gradient just below the high-velocity layer is explained by the ponding of magma at the top of the AMC; this could provide the overpressure for lateral dike propagation along the ridge axis, leading to a complex interaction between magma emplacement, tectonic, and hydrothermal processes, and creating a diversity of seafloor morphology and extremely heterogeneous crust.; MOST (China Ministry of Science and Technology) [2012CB417301, DYXM-115-02-3-01]; National Science Foundation of China [41030857]; InterRidge/International Seabed Authority Endowment Fund Fellowship; SCI(E); ARTICLE; 2; 143-146; 45
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/475421]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Jian, Hanchao,Singh, Satish C.,Chen, Yongshun John,et al. Evidence of an axial magma chamber beneath the ultraslow-spreading Southwest Indian Ridge[J]. GEOLOGY,2017.
APA	Jian, Hanchao,Singh, Satish C.,Chen, Yongshun John,&Li, Jiabiao.(2017).Evidence of an axial magma chamber beneath the ultraslow-spreading Southwest Indian Ridge.GEOLOGY.
MLA	Jian, Hanchao,et al."Evidence of an axial magma chamber beneath the ultraslow-spreading Southwest Indian Ridge".GEOLOGY (2017).