An ultraslow-spreading class of ocean ridge

  title={An ultraslow-spreading class of ocean ridge},
  author={Henry J. B. Dick and Jian Lin and Hans Schouten},
New investigations of the Southwest Indian and Arctic ridges reveal an ultraslow-spreading class of ocean ridge that is characterized by intermittent volcanism and a lack of transform faults. We find that the mantle beneath such ridges is emplaced continuously to the seafloor over large regions. The differences between ultraslow- and slow-spreading ridges are as great as those between slow- and fast-spreading ridges. The ultraslow-spreading ridges usually form at full spreading rates less than… 
The Ultraslow Spreading Southwest Indian Ridge
The Southwest Indian Ridge (SWIR) is among the world’s slowest spreading ridges with a full spreading rate of ~14 mm a−1 (at 64°E/28°S). The compilation of geophysical and geochemical data along the
First active hydrothermal vents on an ultraslow-spreading center: Southwest Indian Ridge
The ultraslow-spreading Southwest Indian Ridge is a major tectonic province, representing one of the important end-member mid-ocean-ridge types for its very slow and oblique spreading, and providing
Melting and Mantle Flow at Oblique Ultraslow-Spreading Ridges
Ultraslow-spreading ridges are a unique endmember of the mid-ocean ridge spreading system. Ultraslow-spreading ridges lack transform faults and often form segments oriented at an oblique angle to the
Mantle flow and melting underneath oblique and ultraslow mid‐ocean ridges
Mid‐ocean ridge morphology correlates strongly with spreading rate. As the spreading rate decreases, conductive cooling becomes more important in controlling ridge thermal structure and the axial
Ultraslow Spreading and Volcanism at the Eastern End of Gakkel Ridge, Arctic Ocean
Ultraslow spreading ridges are poorly understood plate boundaries consisting of magmatic and amagmatic segments that expose mostly mantle peridotite and only traces of basalt and gabbro. The slowest
Magmatic versus amagmatic : a study of local seismicity and lithospheric structure at two contrasting Southwest Indian Ridge segments
New seafloor is constantly being created at the global spanning system of mid-ocean ridges (MOR). Over a wide range of spreading rates is the produced oceanic crust of surprisingly uniform thickness
Hydrothermal venting in magma deserts: The ultraslow‐spreading Gakkel and Southwest Indian Ridges
Detailed hydrothermal surveys over ridges with spreading rates of 50–150 mm/yr have found a linear relation between spreading rate and the spatial frequency of hydrothermal venting, but the validity
Microseismicity of the ultraslow-spreading Gakkel ridge, Arctic Ocean: A pilot study
SUMMARY The active mid-ocean ridge of the Arctic Ocean, named Gakkel ridge, is the slowest spreading ridge of the global system of mid-oceanic ridges with full spreading rates declining from about
Asymmetric crustal structure of the ultraslow-spreading Mohns Ridge
ABSTRACT New analysis of the geophysical data of the ultraslow-spreading Mohns Ridge and its off-axis structure reveals a distinctive asymmetric structure. We calculate residual bathymetry (RB) and


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.
Evidence of recent volcanic activity on the ultraslow-spreading Gakkel ridge
It is demonstrated that eruptions along the ultraslow-spreading Gakkel ridge are focused at discrete locations and appear to be more voluminous and occur more frequently than was previously thought.
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
Geophysical evidence for reduced melt production on the Arctic ultraslow Gakkel mid-ocean ridge
S seismic evidence is presented for the presence of exceptionally thin crust along the Gakkel ridge rift valley with crustal thicknesses varying between 1.9 and 3.3 km, implying that these magma production and transport systems have been stable over this timescale.
Dependence of ridge-axis morphology on magma supply and spreading rate
WHY do some mid-ocean-ridge axes have as their topographic expression a median valley 1–2 km deep and 15–30 km wide, whereas others have an axial high 100–200 m high and 1–2 km wide? In general,
Melt Generation at Very Slow-Spreading Oceanic Ridges: Constraints from Geochemical and Geophysical Data
We show that there is a strong and consistent correlation between geochemical and geophysical estimates of the amount of melt generated in the mantle beneath oceanic ridges. This correlation holds
Oblique rifting in a slow-spreading ridge
IN oceanic rifts, the spreading direction is usually nearly perpendicular to the ridge axis, but at the Reykjanes1 and Mohns2–4 ridges this direction is highly oblique (30° to 40° to the axis). These