Buckling of the Oceanic Lithosphere from Geophysical Data and Experiments

_Abstract. Two major hypotheses have been advanced for the formation of the long wavelength (100-300 km) undulations of oceanic basement and overlying sediments developed in the central Indian Ocean basin: whole layer folding (buckling) and local thickening (inverse boudinage). Using appropriately scaled two-layer analogue models for the oceanic lithosphere comprising a brittle layer above a ductile layer, we show that buckling of the entire brittle layer is likely to be the mode of deformation. However, the lithosphere-asthenosphere boundary remains undisturbed. We find a relationship between the thickness of the brittle layer and the wavelength of folding such that the wavelength is 7 times the brittle layer thickness.