EGU25-18143, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-18143
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
MAPRIDGES: Geometry of global mid-ocean ridge plate boundaries, and the role of transform faults and non-transform offsets
Javier Escartín1, Benjamin Sautter2,3, Carmen Gaina4, Sven Petersen5, Roi Granot6, and Manuel Pubelier1,2
Javier Escartín et al.
  • 1CNRS, UMR8538, Paris, France (escartin@geologie.ens.fr)
  • 2CGMW, 77 rue Claude Bernard, 75005 Paris, France
  • 3Geo-Ocean, Univ Bretagne Sud, Univ Brest, CNRS, Ifremer, UMR6538, F-56000 Vannes, France
  • 4Centre for Planetary Habitability, PHAB, University of Oslo, Sem Sælands vei 24, PO Box 1048, Blindern, NO-0316 Oslo, Norway
  • 5GEOMAR – Helmholtz Centre for Ocean Research, Kiel, Germany
  • 6Department of Earth and Environmental Sciences, Ben‐Gurion University of the Negev, Beer‐Sheva, Israel

The global mid-ocean ridge system produces the oceanic lithosphere accounting for ~70% of the Earth’s surface, while hosting active processes (tectonic, volcanic, hydrothermal circulation). The ridge system is segmented by both transform faults and non-transform offsets, and their geometry can be now re-evaluated with existing multibeam bathymetry (with a resolution of ~100 m or better), both from publicly accessible datasets (e.g., GMRT, NCEI, Pangaea, AWI, among others) and available through published studies. This high-resolution bathymetry is now available for ~25% of the ocean seafloor, but covers a significant proportion of the global mid-ocean ridge system (>70%) and is thus suitable to refine and finely define its geometry. 

 

The MAPRIDGES database (https://doi.org/10.17882/99981) provides a global dataset that includes the newly-defined geometry of individual mid-ocean ridge segments, the most complete catalog to date of transform faults, and identifies non-transform offsets (NTOs). This effort is linked to the World 5M project by CGMW (Commission for the Geological Map of the World). We calculate the lateral offset associated with these NTOs, and determine if they correspond to overlaps of adjacent segments or if they are associated with a gap (underlap). Two different plate models (MORVEL and GSRM) are used to estimate  the length of overlaps, underlaps and their links to variations in spreading direction.

 

Our new database, gives a global, detailed view of the global mid-ocean ridge geometry, and provides the first  evaluation of the overall lengths of ridges and associated lateral offsets, both transform and non-transform. Mid ocean ridge segments (1471) show a cumulative length of ~71200 km, with and along-axis distance of ~4800 km of overlapping segments, and ~1700 km of underlap; taking these offsets into account this yields a total length of along-axis segments of ~75300 km. We have also digitized the traces of 262 transform faults to obtain the most complete catalogue to date of these structures. Transform faults account for a cumulative lateral offset of ridges of ~27000 km. We report a first estimate of the lateral offset of 1058 identified NTOs at ~10400 km, accounting for >30% of the cumulative transform fault length. The resulting cumulative lateral offset from both transform and non-tranform segments is thus ~37400 km, and is ~50% of the total ridge length. As in the case of transform faults, these NTOs are associated with deformation of a significant volume of the recently accreted oceanic lithosphere, and thus likely facilitating hydrothermal circulation and alteration of the lithosphere. This study will facilitate the quantification of these processes and provides a basis to better understand their implications on local and global environments (e.g., chemical fluxes associated with alteration at all offsets).

How to cite: Escartín, J., Sautter, B., Gaina, C., Petersen, S., Granot, R., and Pubelier, M.: MAPRIDGES: Geometry of global mid-ocean ridge plate boundaries, and the role of transform faults and non-transform offsets, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18143, https://doi.org/10.5194/egusphere-egu25-18143, 2025.