Sedimentology, mineralogy, geochemistry and plalynology of Domerian systems tracts of the northern Quercy (NE Aquitain Basin)

The middle and upper parts of the northern Quercy Domerian comprise 7 succe ssive lithological levels which are distinct with respect to sedimentology, palaeontology and facies. Mineralogical and geochemical analysis of the La poujade reference section revealed, firstly, a lowering in sea level accomp anied by a decrease in kaolinite and an increase in illite contents, and, s econdly, a regressive tendancy of the environmental deposits marked by the strontium - the most significant geochemical element. The output of this wo rk allowed to improve and refine our understanding of this section in terms of sequence stratigraphy, primarily based on sedimentary data and on the g eometric organization of the deposits. Three depositional sequences and sev en systems tracts were identified and characterized; this includes the disc ontinuities separating them. Mineralogical and palynological data allowed t o recognize a major climatic change at a sequence boundary, suggesting a re lationship between eustatic variations and climatic phenomena.