Talc-dominated seafloor deposits reveal a new class of hydrothermal system

Hodgkinson, Matthew; Webber, Alexander; Roberts, Stephen; Mills, Rachel A.; Connelly, Douglas P.; Murton, Bramley J. ORCID: https://orcid.org/0000-0003-1522-1191. 2015 Talc-dominated seafloor deposits reveal a new class of hydrothermal system. Nature Communications, 6. 10150. 10.1038/ncomms10150

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Abstract/Summary

The Von Damm Vent Field (VDVF) is located on the flanks of the Mid-Cayman Spreading Centre, 13 km west of the axial rift, within a gabbro and peridotite basement. Unlike any other active vent field, hydrothermal precipitates at the VDVF comprise 85–90% by volume of the magnesium silicate mineral, talc. Hydrothermal fluids vent from a 3-m high, 1-m diameter chimney and other orifices at up to 215 °C with low metal concentrations, intermediate pH (5.8) and high concentrations (667 mmol kg−1) of chloride relative to seawater. Here we show that the VDVF vent fluid is generated by interaction of seawater with a mafic and ultramafic basement which precipitates talc on mixing with seawater. The heat flux at the VDVF is measured at 487±101 MW, comparable to the most powerful magma-driven hydrothermal systems known, and may represent a significant mode of off-axis oceanic crustal cooling not previously recognized or accounted for in global models.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1038/ncomms10150
ISSN:	2041-1723
Date made live:	22 Oct 2015 15:34 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/512084

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1038/ncomms10150

ISSN:

2041-1723

Date made live:

22 Oct 2015 15:34 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/512084