Book contents
- Frontmatter
- Contents
- Preface
- Sensitivity of teleseismic body waves to mineral texture and melt in the mantle beneath a mid-ocean ridge
- Evidence for accumulated melt beneath the slow-spreading Mid-Atlantic Ridge
- An analysis of variations in isentropic melt productivity
- A review of melt migration processes in the adiabatically upwelling mantle beneath oceanic spreading ridges
- Rift-plume interaction in the North Atlantic
- The ultrafast East Pacific Rise: instability of the plate boundary and implications for accretionary processes
- Seafloor eruptions and evolution of hydrothermal fluid chemistry
- Controls on the physics and chemistry of seafloor hydrothermal circulation
- Where are the large hydrothermal sulphide deposits in the oceans?
- Sea water entrainment and fluid evolution within the TAG hydrothermal mound: evidence from analyses of anhydrite
- Thermocline penetration by buoyant plumes
- Crustal accretion and the hot vent ecosystem
- Biocatalytic transformations of hydrothermal fluids
- Index
Where are the large hydrothermal sulphide deposits in the oceans?
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- Preface
- Sensitivity of teleseismic body waves to mineral texture and melt in the mantle beneath a mid-ocean ridge
- Evidence for accumulated melt beneath the slow-spreading Mid-Atlantic Ridge
- An analysis of variations in isentropic melt productivity
- A review of melt migration processes in the adiabatically upwelling mantle beneath oceanic spreading ridges
- Rift-plume interaction in the North Atlantic
- The ultrafast East Pacific Rise: instability of the plate boundary and implications for accretionary processes
- Seafloor eruptions and evolution of hydrothermal fluid chemistry
- Controls on the physics and chemistry of seafloor hydrothermal circulation
- Where are the large hydrothermal sulphide deposits in the oceans?
- Sea water entrainment and fluid evolution within the TAG hydrothermal mound: evidence from analyses of anhydrite
- Thermocline penetration by buoyant plumes
- Crustal accretion and the hot vent ecosystem
- Biocatalytic transformations of hydrothermal fluids
- Index
Summary
Large sulphide deposits have been identified on slow and fast spreading ridges and back-arc basins. Their formation is controlled by a combination of several conditions, each of which alone is often only compatible with the formation of small and unstable deposits. The geological control of deposits has to be considered both at the regional and local scales. The convective system is dependent on the morphology of the heat source (magma chamber) and the magma supply. Major sites are controlled by regional topographic highs that are the locus of the highest magma and heat supply along the ridge. On slow spreading ridges the flow of hydrothermal fluids can also be controlled by major regional rift valley faults. The discharge within a field is controlled by the local near surface permeability related to faulting or permeability of rocks. Recent discoveries considerably enlarge the potential locations of hydrothermal activity. On slow spreading ridges we have now to consider the base and top of the rift valley walls and the non-transform offsets, in addition to the relatively well documented control by volcanic topographic highs. Known sites also demonstrate that slow spreading ridges are more favourable for the formation of extensive mineralization. On fast spreading ridges, deposits are numerous and very small because the upflow zone is relatively narrow and subject to perturbation by frequent tectonic and volcanic activity. However, near fast spreading ridges, first order sulphide deposits can be formed on off-axial seamounts. Geological and physical conditions are key parameters controlling the morphology and potential size of deposits.
- Type
- Chapter
- Information
- Mid-Ocean RidgesDynamics of Processes Associated with the Creation of New Oceanic Crust, pp. 211 - 224Publisher: Cambridge University PressPrint publication year: 1999
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