Based on
outcrop, core, well log and seismic data,Johnson and Alam (1991)
proposed that the Sylhet basin evolved from being a Pre-Oligocene passive continental margin into an Oligocene and Miocene foreland basin linked to the Indo-Burman Ranges. The foreland basin
developed further during the Pliocene to Holocene in response to
south-directed overthrusting of the Shillong Massif