Three-dimensional accommodation analysis of the keuper of the paris basin: discrimination between tectonics, eustasy and sediment supply in the stratigraphic record

摘要

During the Keuper, the Paris Basin was an intracratonic sedimentary basin filled by continental deposits. Using paleo-environmental, isopach and paleo-altitude maps, we estimate the variations of accommodation rate at the scale stratigraphic minor hemi-cycle (1-3 Ma). An analysis of the short- and long-wavelength accommodation variations allows us to assess the relative influence of tectonics, eustasy and sediment supply on the stratigraphic record. Our data suggest a pattern of subsidence along three trends: E-W in the Carnian, E-W to NNE-SSW in the Norian and NE-SW in the Norian-Rhaetian. During the Keuper, the Paris Basin accurately records the different phases of the opening of the Tethys Ocean associated with a rotation of the extension direction. The Norian cycle could thus reflect the intraplate stresses in a transitional period between the Triassic and the Liassic.