Propagation of detrital signals in the source- to-sink systems of the Tremp-Graus-Ainsa basins, Southern Pyrenean Foreland Basin, Spain

Late Cretaceous to Oligocene sedimentary fill of the Southern Pyrenean foreland basin consist of clastic and carbonate sediments deposited in an active tectonic system of piggyback foreland basin, which provides a record of the uplift, thrust movements, weathering and erosion of the growing mountain range. The very good outcrop conditions, continuity and stratigraphic framework of these well dated deposits make them an ideal laboratory to study how, in this tectonically active environment, and during a period of changing climates (paleogene-neogene), sediment pathways and provenance can be reconstructed. Previous research has identified several sources of sediment, as for instance southern and northern carbonate platforms acting as sources for shallow water carbonate clasts brought in the basin and an eastern-southeastern fluvial input for siliciclastic sediments (Dreyer et al., 1999 ; Fontana et al., 1989 ; Mutti, 1983 ; Payros et al., 2009). So far, most studies have focused separately either on the sandstone provenance in the fluvial- alluvial environment of the TrempGraus sub- basin, or on the deep-marine environment of the Ainsa sub-basin, without considering the whole source-to-sink relationship between these basins. There is therefore a lack of regional-scale sandstone provenance study that we offer to intend with a fast-forward method of petrographic evaluation of siliciclastic sediments. In this study an analytical tool, QEMScan (Quantitative Evaluation of Materials by Scanning Electron Microscopy), is used as a new method for accurately quantifying petrography and provenance of the sediments and source rocks from the basement. The method uses polished thin sections. We double-check QEMSCAN results with classical optical microscopy and X-ray diffraction. It is our aim to provide insight into the sediment transport patterns and sediment source by observing several detrital signals such as mineralogical variability, heavy mineral ratios and clay minerals ratios and understand the source-to-sink relationship in this basin.