Makarov Basin extinct ridge

ID: 4-13

Observations and comments:

Due to its extreme northerly latitude, which is beyond the extent of the global bathymetry and gravity grids used in this study, this proposed extinct ridge was not included within the comparative study that accompanies this dataset.

Ocean: Marginal basin, Arctic Circle
Spreading center type: Large-scale extinct MOR
Time of cessation: Chron C21 (Seton et al., 2012)
Subsequent active spreading center: Gakkel Ridge was spreading simultaneously in the later stages of the ridges life, with concurrent magmatism in the Alpha Ridge-Mohns Ridge and southern basins.

Review of previous studies:

Taylor et al. (1981), made a ‘tentative’ identification of magnetic anomalies within the basin and proposed that the opening of the basin had been related to the Baffin Bay and Labrador Sea opening, which is strongly disputed by Christopher et al., (2011). The location of the former axis of spreading was inferred by Taylor et al. (1981) to be situated between 84 and 87° N and from 120 to 160° W. The basin is thought to have been active from the late Cretaceous Quiet Zone or around the time of anomaly C34 until C21, simultaneous with opening of the Baffin Bay (Taylor et al., 1981).

The depth of the basin is not seen to be consistent with the inferred age according to the age-depth relationship demonstrated by Sclater et al. (1971). Taylor et al. (1981) thus infer that smaller and marginal basins may not achieve a thermal equilibrium that is equivalent to larger basins. Despite a detailed seismic study of the Makarov Basin, information on the extinct ridge that formed the oceanic crust in this region is relatively limited, which may in part be due to the extensively thickened lower crust reported in the basin (Sorokin et al., 1999). Oceanic 'Layer 3' is reported to be up to 15 km thick and is thought to have been influenced by anomalous, regional mantle temperature, such as by a proximal hotspot (Sorokin et al., 1999).

Suggested reasons for cessation:

Changes in both spreading rate and the direction of opening are argued to have occurred at around the time of anomaly C24 (Taylor et al. 1981), which is believed to be strongly related to the Northern Atlantic opening and may have contributed to cessation.


Christopher, T., Pulvertaft, R. and Dawes, P. R., 2011, North Atlantic spreading axes terminate in the continental cul-de-sacs of Baffin Bay and the Laptev Sea, Canadian Journal of Earth Science, v. 48, p. 593-601.

Sorokin, M.Y., Zamansky, Y.Y., Langinen, A.Y., Jackson, H.R. and Macnab, R., 1999, Crustal structure of the Makarov Basin, Arctic Ocean determined by seismic refraction. Earth and Planetary Science Letters, v. 168, p. 187–199.

Taylor, P.T., Kovacs, L.C., Vogt, P.R. and Johnson, G.L., 1981, Detailed aeromagnetic investigation of the Arctic Basin, v. 86, pp.6323–6333.