Abstract: Depositional Sequence Cycles, Transgressive-Regressive Facies Cycles and Extensional Tectonics in the Western Europe Liassic
Pierre Charles De Graciansky, Thierry Jacquin
The concepts of Sequence Stratigraphy have been applied to the outcrop and subsurface sediments of the Early Jurassic Paris basin compared to the Subalpine and Aquitaine basins (France), the Dorset and Yorkshire basins (UK) and the North Sea basins. Long distance correlation is given by ammonite determination at the horizon level for most of the stratigraphic cycles. The Lower Jurassic is comprised between two sequence boundaries related to a first order continental encroachment cycle (duration : 43 MY). Five second order Transgressive/Regressive Facies Cycles (average duration : 7 MY) and 28 third order sequence cycles (average duration: 1,4 MY) have been identified in basinal areas where the cycles boundaries are conformable. 3rd order sequence cycles can be traced from the North to the South of Europe. Their organization is depending from their place within the 2nd order Transgressive/Regressive Cycles. The 2nd order Transgressive/Regressive Cycles are different in amplitude and age depending on the time and the place. Their age and their characteristics help to document the evolution of the intraplate strain changes in relation with the development of the neighbouring Atlantic and Tethyan margins.
AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France