Modes of faulting at mid-ocean ridges

  title={Modes of faulting at mid-ocean ridges},
  author={W. Roger Buck and Luc L. Lavier and Alexei N. B. Poliakov},
Abyssal-hill-bounding faults that pervade the oceanic crust are the most common tectonic feature on the surface of the Earth. The recognition that these faults form at plate spreading centres came with the plate tectonic revolution. Recent observations reveal a large range of fault sizes and orientations; numerical models of plate separation, dyke intrusion and faulting require at least two distinct mechanisms of fault formation at ridges to explain these observations. Plate unbending with… 
Oceanic detachment faults generate compression in extension
In extensional geologic systems such as mid-ocean ridges, deformation is typically accommodated by slip on normal faults, where material is pulled apart under tension and stress is released by
Dynamical Instability Produces Transform Faults at Mid-Ocean Ridges
Numerical models suggest that transform faults are actively developing and result from dynamical instability of constructive plate boundaries, irrespective of previous structure.
Magmatic and tectonic extension at mid‐ocean ridges: 1. Controls on fault characteristics
We use 2‐D numerical models to explore the thermal and mechanical effects of magma intrusion on fault initiation and growth at slow and intermediate spreading ridges. Magma intrusion is simulated by
Central role of detachment faults in accretion of slow-spreading oceanic lithosphere
An examination of ∼2,500 km of the Mid-Atlantic Ridge between 12.5 and 35° N is presented, which reveals asymmetrical accretion along almost half of the ridge, suggesting that much of the variability in sea-floor morphology, seismicity and basalt chemistry found along slow-spreading ridges can be thus attributed to the frequent involvement of detachment faults in oceanic lithospheric accretion.
Modes of seafloor generation at a melt-poor ultraslow-spreading ridge
We report on extensive off-axis bathymetry, gravity, and magnetic data that provide a 26-m.y.-long record of axial tectonic and magmatic processes over a 660-km-long and melt-poor portion of the
Tectonic versus magmatic extension in the presence of core complexes at slow-spreading ridges from a visualization of faulted seafloor topography
We develop a forward model of the generation of faulted seafloor topography (visualization) to estimate the relative roles of tectonic and magmatic extension in the presence of core complexes at


Abyssal hills formed by stretching oceanic lithosphere
Tectonic plates are formed and move apart at mid-ocean ridges. Some portion of this plate-separation process can occur by stretching of the crust, resulting in a complex pattern of extensional
A simple model for the fault‐generated morphology of slow‐spreading mid‐oceanic ridges
We postulate that fluctuations in magmatic activity at mid-oceanic ridges perturb the horizontal least principal stress across rift-bounding normal faults, leading to alternating phases of magmatic
Causes of variation in fault-facing direction on the ocean floor
A marked variation in fault-facing direction with spreading rate is observed on the flanks of mid-ocean ridges. On slow- and intermediate-rate spreading centers inward-facing faults predominate,
A geological model for the structure of ridge segments in slow spreading ocean crust
First-order (transform) and second-order ridge-axis discontinuities create a fundamental segmentation of the lithosphere along mid-ocean ridges, and in slow spreading crust they commonly are
Corrugated slip surfaces formed at ridge–transform intersections on the Mid-Atlantic Ridge
The strips of ocean crust formed at the inside corners of both transform and non-transform offsets on the Mid-Atlantic Ridge are punctuated by topographic highs—the 'inside-corner highs'1–3—where
Relationship between spreading rate and the seismic structure of mid-ocean ridges
DIFFERENT parts of the global mid-ocean ridge system create oceanic crust at rates that differ by more than a factor of ten. The rates of supply of heat to these different systems must also vary
Correction: 'Necking of the Lithosphere and the Mechanics of Slowly Accreting Plate Boundaries'
Data on ridges with slow spreading rates (1–3 cm/yr), obtained through detailed studies with Deep-Tow instruments and manned submersibles (French-American Mid-Ocean Undersea Study), or where the
The Gakkel Ridge: Bathymetry, gravity anomalies, and crustal accretion at extremely slow spreading rates
[1] The Gakkel Ridge in the Arctic Ocean is the slowest spreading portion of the global mid-ocean ridge system. Total spreading rates range from 12.7 mm/yr near Greenland to 6.0 mm/yr where the ridge
Magmatic and amagmatic seafloor generation at the ultraslow-spreading Gakkel ridge, Arctic Ocean
Observations of the Gakkel ridge demonstrate that the extent of mantle melting is not a simple function of spreading rate: mantle temperatures at depth or mantle chemistry (or both) must vary significantly along-axis.
Accretional curvature of lithosphere at magmatic spreading centers and the flexural support of axial highs
Fluid magma should tend to rise up to the level of local isostatic equilibrium at an axis of plate spreading. The magma and underlying partial melt accretes to the side of the separating plates and