%0 Journal Article
%A Barrón López, Eduardo
%A Ureta Gil, María Soledad
%A Goy, Antonio
%A Lassaleta Coto, Luis
%T Palynology of the Toarcian–Aalenian Global Boundary Stratotype Section and Point(GSSP) at Fuentelsaz (Lower–Middle Jurassic, Iberian Range, Spain)
%D 2010
%@ 0034-6667
%U https://hdl.handle.net/20.500.14352/42338
%X The Fuentelsaz Section is located in the Castilian Branch of the Iberian Range (Guadalajara, Spain). Itsexceptional Lower–Middle Jurassic transition outcrops led to its designation as the Global BoundaryStratotype Section and Point for the base of the Aalenian. The sediments of the Toarcian–Aalenian transitionat Fuentelsaz are composed of marls with interbedded limestones in rhythmic alternation. Marls aredominant in the Toarcian and the Opalinum Zone up to the middle part of the Comptum Subzone. In theremaining Comptum Subzone, marly materials are scarce and limestones predominate. Sedimentation atFuentelsaz took place over an extensive marine epeiric carbonate platform that was well connected with theopen sea. In the Fuentelsaz Section, a total of 43 palynomorph taxa were recorded: 23 spore taxa, 13 pollentaxa, 4 acritarchs, 2 prasinophytes and 1 dinoflagellate cyst. The studied sediment samples were alwaysdominated by terrestrial allochthonous miospores. In general, miospore assemblages are biased due to thetransport of pollen from land or islands to the continental platform. Spheripollenites, Classopollis or indeedboth pollens numerically dominate the assemblages. Other miospores appear in low numbers. Aquaticpalynomorphs are also scarce; Micrhystridium lymensis is the most common. Five palynological assemblages(PA) were distinguished: PA1, PA2 and PA3 are Toarcian in age, PA4 is located at the boundary between theToarcian and the Aalenian and PA5. This latter palynological assemblage which is lower Aalenian in ageshows a strong reduction in palynomorph diversity and preservation in the Comptum Subzone.Palaeoecological analysis of the palynomorphs indicated the presence of calm, oligotrophic sea water. Thepalaeofloral communities of gymnosperms and vascular cryptogams—which grew in subtropical aridconditions—were poorly diversified.
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