Upper Jurassic microsolenid biostromes of northern and central Europe: facies and depositional environment

摘要: Abstract Microsolenid biostromes are a common and important reef type in many Upper Jurassic reefal sections. Comparative study of these western Europe allows the characterisation this distinct biostrome terms its taxonomic composition, palaeoecology sedimentary regime. The characterised by coral community relatively low generic diversity, being dominated Microsolenidae family corals. skeletal biovolume is generally high overwhelmingly platy ecomorphotypes. Sedimentologically developed energy marl limestone regimes which were subject to sedimentation rates varying degrees siliciclastic influx. In contrast fauna associated shows particular rich assemblage echinoids bivalves. addition plates provide an ideal habitat for well strongly polarised encrusting boring fauna. Top surfaces show limited post-mortem encrustation serpulids cementing bivalves, also bored lithophagan undersides highly diverse cryptic serpulids, thecidean brachiopods, bryozoans, calcareous sponges sclerosponges. It concluded that main control on development was light intensities, though level background important. suggested nutrient levels may have played significant role. conditions microsolenid prevail deep-water environments, hence first coral-dominated structures deeper water shallowing upward sequences. corals adapted developing growth form, but reducing their substantially. microsolenids particularly environments two ways: (1) They secreted extremely porous calcium carbonate skeleton, where calcification slow, such as deep advantage; (2) response potential phototrophy pennular septal structure be means improving heterotrophic feeding. Trophic analysis reveals limitation model present-day reefs cannot applied biostromes. demonstrated Microsolena agariciid, Leptoseris number morphological ecological similarities.