Denudation of the Côte d'Ivoire-Ghana transform margin from apatite fission tracks.

Florence Bigot-Cormier (1) , Christophe Basile (2) , Gérard Poupeau (3) , Jean-Pierre Bouillin (2) , Erika Labrin (2)

1 GEOAZUR 6526 - Géoazur
2 LGCA - Laboratoire de Géodynamique des Chaines Alpines
3 IRAMAT - Institut de Recherches sur les Archéomatériaux

Apatite fission track analysis of samples from the shoulder (marginal ridge) of the Côte d'Ivoire-Ghana transform continental margin reveal a cooling of the margin between 85 and 65 Ma for the central and eastern parts of the ridge. All samples were heated in situ during sedimentary burial with a temperature >120 °C, except for two samples located in the eastern part which were heated between 105 and 120 °C. For the first time, age/depth diagram along a transform margin shows a shape involving erosion starting at the bottom of the continental slope, then stepping backwards towards the edge of the slope. This retrogressive erosion can result from the deepening of the lithospheric plate sliding along the transform margin, from thick continental crust to thin continental crust, and finally to oceanic crust. This process could be at the origin of the shoulder uplift by flexural response to the important crustal discharge (>2 km).

Domaines: Géochimie

Florence Bigot-Cormier, Christophe Basile, Gérard Poupeau, Jean-Pierre Bouillin, Erika Labrin. Denudation of the Côte d'Ivoire-Ghana transform margin from apatite fission tracks.. Terra Nova, 2005, 17(2), pp.189-195. ⟨10.1111/j.1365-3121.2005.00605.x⟩. ⟨hal-00096370⟩