The deep structure of a sea-floor hydrothermal deposit

Nature
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Abstract

Hydrothermal circulation at the crests of mid-ocean ridges plays an important role in transferring heat from the interior of the Earth. A consequence of this hydrothermal circulation is the formation of metallic ore bodies known as volcanic-associated massive sulphide deposits. Such deposits, preserved on land, were important sources of copper for ancient civilizations and continue to provide a significant source of base metals (for example, copper and zinc). Here we present results from Ocean Drilling Program Leg 169, which drilled through a massive sulphide deposit on the northern Juan de Fuca spreading centre and penetrated the hydrothermal feeder zone through which the metal-rich fluids reached the sea floor. We found that the style of feeder-zone mineralization changes with depth in response to changes in the pore pressure of the hydrothermal fluids and discovered a stratified zone of high-grade copper-rich replacement mineralization below the massive sulphide deposit. This copper-rich zone represents a type of mineralization not previously observed below sea-floor deposits, and may provide new targets for land-based mineral exploration.
Publication type Article
Publication Subtype Journal Article
Title The deep structure of a sea-floor hydrothermal deposit
Series title Nature
DOI 10.1038/33126
Volume 392
Issue 6675
Year Published 1998
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Nature
First page 485
Last page 488
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