Original Research Paper

Marine Geophysical Researches

, Volume 31, Issue 3, pp 173-195

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Crustal structure of the ultra-slow spreading Knipovich Ridge, North Atlantic, along a presumed ridge segment center

  • Aleksandre KandilarovAffiliated withDepartment of Earth Science, University of Bergen Email author 
  • , Hildegunn LandaAffiliated withDepartment of Earth Science, University of Bergen
  • , Rolf MjeldeAffiliated withDepartment of Earth Science, University of Bergen
  • , Rolf B. PedersenAffiliated withDepartment of Earth Science, University of Bergen
  • , Kyoko OkinoAffiliated withOcean Research Institute, University of Tokyo
  • , Yoshio MuraiAffiliated withInstitute of Seismology and Volcanology, Hokkaido University


A combined ocean bottom seismometer, multichannel seismic reflection and gravity study has been carried out along the spreading direction of the Knipovich Ridge over a topographic high that defines a segment center. The youngest parts of the crust in the immediate vicinity of the ridge reveal fractured Oceanic Layer 2 and thermally expanded and possibly serpentinized Oceanic Layer 3. The mature part of the crust has normal thickness and seismic velocities with no significant crustal thickness and seismic velocity variations. Mature Oceanic Layer 2 is in addition broken into several rotated fault blocks. Comparison with a profile acquired ~40 km north of the segment center reveals significant differences. Along this profile, reported earlier, periods of slower spreading led to generation of thin crust with a high P-wave velocity (Vp), composed of a mixture of gabbro and serpentinized mantle, while periods of faster spreading led to generation of more normal gabbroic crust. For the profile across the segment center no clear relation exists between spreading rate and crustal thickness and seismic velocity. In this study we have found that higher magmatism may lead to generation of oceanic crust with normal thickness even at ultra-slow spreading rates.


Knipovich Ridge Ultra-slow spreading Crustal structure Refraction seismics Ocean bottom seismometer Multichannel seismic reflection