%0 Journal Article
%A Chacón Pichaco, Beatriz
%A Martín Chivelet, Javier
%T Stratigraphy of Palaeocene phosphate pelagic stromatolites(Prebetic Zone, SE Spain)
%D 2008
%@ 0172-9179
%U https://hdl.handle.net/20.500.14352/50512
%X The hemipelagic domain of the ancient southerncontinental margin of Iberia is home to a strongly condensedpelagic succession (6–15 cm thick) characterized bythe presence of phosphate stromatolites. This succession,probably generated in the slope of the continental margin,records a period of some 9 Ma, corresponding to the latestMaastrichtian to Late Thanetian interval. A microstratigraphicalanalysis allows for characterizing and biostratigraphicallydating six successive developmental stages inthe succession, which outline the main environmental evolutionof the depositional setting. The Wrst of them determinedthe generation of a submarine hardground during thelatest Maastrichtian to earliest Danian interval. The otherWve are represented by Wve successive microstratigraphical,unconformity-bounded, genetic units, respectively Early–Middle Danian, Late Danian–Early Selandian, intra-Selandian,Late Selandian–Early Thanetian, and Middle–?LateThanetian in age. The three oldest units are characterizedby the accretion of phosphate stromatolites, favoured byvery low rates of pelagic sedimentation and by a microbiallymediated extra input of phosphate. The two youngestunits are dominated by carbonate deposition, which hasalways taken place at very low rates. Condensed sedimentationwas abruptly interrupted at the end of the Palaeocene(?latest Thanetian), when the condensed succession and itshosting substrate were gravitationally slumped and redepositedat the base of the slope in the form of a megadebrisXow that can be now observed in Sierra de Aixorta(Alicante, SE Spain). The Aixorta pelagic phosphatic stromatolitesare among the youngest ever described, and theirexistence suggests that the oceanographic conditions necessaryfor their development prevailed during most of thePalaeocene, but disappeared during the Late Selandian,never to return.
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