High-resolution magnetic signature of active hydrothermal systems in the back-arc spreading region of the southern Mariana Trough

Fujii, Masakazu, Okino, Kyoko, Honsho, Chie, Dyment, Jerome, Szitkar, Florent, Mochizuki, Nobutatsu and Asada, Miho (2015) High-resolution magnetic signature of active hydrothermal systems in the back-arc spreading region of the southern Mariana Trough Journal of Geophysical Research: Solid Earth, 120 (5). pp. 2821-2837. DOI 10.1002/2014JB011714.

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Abstract

High-resolution vector magnetic measurements were performed on five hydrothermal vent fields of the back-arc spreading region of the southern Mariana Trough using Shinkai 6500, a deep-sea manned submersible. A new 3-D forward scheme was applied that exploits the surrounding bathymetry and varying altitudes of the submersible to estimate absolute crustal magnetization. The results revealed that magnetic-anomaly-derived absolute magnetizations show a reasonable correlation with natural remanent magnetizations of rock samples collected from the seafloor of the same region. The distribution of magnetic-anomaly-derived absolute magnetization suggests that all five andesite-hosted hydrothermal fields are associated with a lack of magnetization, as is generally observed at basalt-hosted hydrothermal sites. Furthermore, both the Pika and Urashima sites were found to have their own distinct low-magnetization zones, which could not be distinguished in magnetic anomaly data collected at higher altitudes by autonomous underwater vehicle due to their limited extension. The spatial extent of the resulting low magnetization is approximately 10 times wider at off-axis sites than at on-axis sites, possibly reflecting larger accumulations of nonmagnetic sulfides, stockwork zones, and/or alteration zones at the off-axis sites.

Document Type: Article
Additional Information: WOS:000356454500001
Keywords: deep-sea magnetics; hydrothermal system; back-arc spreading region; Mariana Trough
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems > Marine Mineralische Rohstoffe
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS Magmatic and Hydrothermal Systems
Refereed: Yes
DOI etc.: 10.1002/2014JB011714
ISSN: 0148-0227
Projects: TAIGA
Date Deposited: 16 Jul 2015 11:36
Last Modified: 02 May 2017 10:43
URI: http://eprints.uni-kiel.de/id/eprint/29253

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