The interaction of eustacy and tectonism fromprovenance studies of the Eocene Hecho Group TurbiditeComplex ( South-Centra Plyrenees Spain)

Using a detailed etrographical procedure conceived for arenites rich in carbonate clasts,the influence of tectonism and eustacy on silicate/carbonate cycles of the Eocene Hecho TurbiditeComplex has been tested,and the palaeogeography of the source/basins ystemo utlined.Both extrabasinal and intrabasinal sources of sediments were active during basin f illing. Forelandt hrusting in the South Central Pyrenees has acted as the major control on the composition and architecture of the Hecho Turbidite Complex. Strong uplift of old silicate andcarbonate source terrains during southward thrust propagation was responsible for erosion, swamping and/or reduction of shelfal areas, and gave rise to siliciclastica nd carbonate basinalsequences.