Las facies espongiolíticas del Jurásico español y unidades semejantes de Europa Central.

Abstract

Ihe sponge facies of the Spanish Jurassic occurs in the Bajocian, Oxfordian and Kimmeridgian. This facies is not restricted to the Celtiberian realm, but it is heme that it reaches its fullest development. A sponge facies is known from the Bajocian of the Cantabrian Mountains and from the Oxfordian of the Betie realm (Prebetic zone), too. The Kimmeridgian spongebearing facies has been aseertained so Lar only a relatively small area of the northeastern Celtiberian domain. The spongiolithic sedimentary structures frequently display a biostromal character. However, it is often only the great abundance of sponges in carbonatie sediments which Iends the limestones this biostromal or biohermal appearance. Bioherms or mud-mound structures can be spoken of only in certain parts of the Celtiberian Bajocian. The sponges (Dictyida, Lychniskida, Lithistida), which are always preserved as carbonatie replacements, are very often burried in an inverted position. Reference is made to the presence of carbonatic crusts ant! of tuberoids, as well as to the microfacies of the diverse sponge-bearing limestones. Finally, mention is made of comparable spongiolithic formations from the Jurassic of Central Europe (France, Switzerland, Southem Germany).