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
Rift-plume interaction in the North Atlantic
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
The style of oceanic crustal formation in the North Atlantic is controlled by interaction between the Iceland mantle plume and the lithospheric spreading. There are three main tectonic regimes comprising: (a) oceanic crust formed without fracture zones, with spreading directions varying from orthogonal up to 30° oblique to the ridge axis; (b) oceanic crust with a normal slow-spreading pattern of orthogonal spreading segments separated by fracture zones; and (c) 20–35 km thick crust generated directly above the centre of the mantle plume along the Greenland-Iceland- Fseroe Ridge. I show that the main control on the tectonic style is the temperature of the mantle beneath the spreading axis. A mantle temperature increase of as little as 50 °C causes an increase of about 30% in the crustal thickness, and thereby allows the mantle beneath the crust at the ridge axis to remain sufficiently hot that it responds to axial extension in a ductile rather than a brittle fashion. This generates crust without fracture zones and with an axial high rather than a median valley at the spreading centre. Using gravity, magnetic, bathymetric and seismic refraction data I discuss the mantle plume temperatures and flow patterns beneath the North Atlantic since the time of continental breakup, and the response of the crustal generation processes to these mantle temperature variations.
- Type
- Chapter
- Information
- Mid-Ocean RidgesDynamics of Processes Associated with the Creation of New Oceanic Crust, pp. 103 - 124Publisher: Cambridge University PressPrint publication year: 1999
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