Upper Albian deposits of the Deba section consist mainly of deep-water turbiditic sandstones and lutites (Black Flysch). In the uppermost part of this section (-120 m), several tens of tephra layers are intercalated between lutites. They are 0.5-18 mm thick tabular layers of tuff and lapiHistone.
Three pyroclastic facies have been distinguished: normal graded tuff/lapiHistone (the most abundant), disorganised lapillistone and normal graded to disorganised tuff/lapi Histone. These facies exhibit characteristics typical of fallout tephra deposits: non-erosive sharp and flat base, lack of lamination, uniformity and lateral wide extent, normal gradation, and lack of terrigenous particles and rip-up clasts. Sedimentological and regional criteria suggest a southern source area for these fallout pyroclastic deposits.
© 2001-2024 Fundación Dialnet · Todos los derechos reservados