Hydrothermal vents at 5000m on the Mid-Cayman Rise: where basement lithology and depth of venting controls sulphide deposit composition


Murton, B., Copley, J., Connelly, D., et al, . and Ship Party JC44 (2011) Hydrothermal vents at 5000m on the Mid-Cayman Rise: where basement lithology and depth of venting controls sulphide deposit composition. In, OCEANS 2011 MTS/IEEE KONA Conference & Exhibition. Oceans 11 Richardson, US, MTS/IEEE, 4pp.

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Description/Abstract

This contribution describes the geological setting of
hydrothermal activity within the Mid-Cayman Rise (MCR) using
data acquired during RRS James Cook cruise JC44 (MAR-APR
2010) from the deep-towed sidescan sonar TOBI, 6000m-diving
AUV Autosub6000 and the Robotic Underwater Vehicle (RUV)
HyBIS. The 110 km-long Mid-Cayman Rise (MCR), located
within the Cayman Trough, Caribbean Sea, is the deepest
seafloor-spreading centre in the world reaching to ~7000m. Its morphology is consistent with ultra-slow-spreading and magnetic anomalies confirm its divergence rate of only ~15 mm yr-1, with active spreading since ~49 Ma. Hence the MCR poses an endmember of extreme depth for oceanic accretion and hydrothermal circulation.

Our sonar imagery revealed accretion of new volcanic crust is focused within two ridge segments, to the north and south of a centrally located massif of peridotite and gabbro. Following earlier indications of hydrothermal plumes [1], we discovered two unique high-temperature hydrothermal system within the MCR: one at a depth of 5000m in the neovolcanic zone of the northern segment of the MCR, and another at 2200m on the flanks of the MCR coincident with the peridotite massif.

These sites show contrasting styles of fluid venting,
mineralisation, geological setting and host rock interaction
enabling us to propose that depth and base,ent lithology plays an important role in controlling the metal tenor of submarine hydrothermal deposits.

Item Type: Book Section
ISBNs: 9780933957398
Keywords: hydrothermal, ultra-deep, super-critical, mineralisation, metal tenor
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
Q Science > QD Chemistry
Q Science > QE Geology
Divisions: Faculty of Natural and Environmental Sciences > Ocean and Earth Science > Ocean Biochemistry & Ecosystems
National Oceanography Centre (NERC) > Marine Geoscience
ePrint ID: 336384
Date Deposited: 22 Mar 2012 15:59
Last Modified: 14 Apr 2014 11:38
Research Funder: NERC
Projects:
Hydrothermal activity and deep-ocean biology of the Mid-Cayman Rise
Funded by: NERC (NE/F017774/1)
Led by: Jonathan Timothy Copley
15 September 2009 to 1 March 2014
Publisher: MTS/IEEE
URI: http://eprints.soton.ac.uk/id/eprint/336384

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