Do faults trigger folding in the lithosphere?

Muriel Gerbault (1) , Eugenii B. Burov (2) , Alexei N.B. Poliakov (1) , Marc Daignières (1)

1 UM - Université de Montpellier
2 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

A number of observations reveal large periodic undulations within the oceanic and continental lithospheres. The question if these observations are the result of large- scale compressive instabilities, i.e. buckling, remains open. In this study, we support the buckling hypothesis by di- rect numerical modeling. We compare our results with the data on three most proeminent cases of the oceanic and continental folding-like deformation (Indian Ocean, Western Gobi (Central Asia) and Central Australia). We demon- strate that under reasonable tectonic stresses, folds can de- velop from brittle faults cutting through the brittle parts of a lithosphere. The predicted wavelengths and finite growth rates are in agreement with observations. We also show that within a continental lithosphere with thermal age greater than 400 My, either a bi-harmonic mode (two superimposed wavelengths, crustal and mantle one) or a coupled mode (mono-layer deformation) of inelastic folding can develop, depending on the strength and thickness of the lower crust.

Mots clés: Lithosphere; Indian Ocean; Buckling; Faulting; Viscoeasto-plasticity

Domaines: Sciences de la Terre

Muriel Gerbault, Eugenii B. Burov, Alexei N.B. Poliakov, Marc Daignières. Do faults trigger folding in the lithosphere?. Geophysical Research Letters, 1999, 26 (2), pp.271-274. ⟨10.1029/1998GL900293⟩. ⟨hal-03157577⟩