DEPOSITIONAL SEQUENCES GEOMETRY OF KEUPER AGE (LADINIAN TO RHAETIAN) OF THE PARIS BASIN - GEODYNAMIC IMPLICATIONS

The geometry at different scales of depositional sequences of Ladinian to Rhaetian age has been reconstructed wing high resolution correlati ons of well-logs across the Paris Basin. The transgressive-regressive cycles are the result of variations in subsidence rate. Two phases of reactivation of Hercynian faults control the distribution of depocente rs and indicate no important extensional movements. The first phase is recorded in the ''Marnes irisees inferieures'' when subsidence preser ved salt deposits. The second phase, during the ''Marnes irisees super ieures'', consists of a general tilt of the basin and migration of dep ocenters to the West.