Calcareous nannofossils of the Jurassic/Cretaceous boundary strata in the Puerto Escano section(southern Spain) - biostratigraphy and paleoecology
Abstrakt
Material from Puerto Escańo section was obtained to study Jurassic/Cretaceous (J/K) boundary interval. The same samples had already been processed for magnetostratigraphic studies and biostratigraphic zonation based on calpionellids and ammonites (Pruner et al. 2010), but not for calcareous nannofossils.
Zhe aim of this study was to process the samples using micropalaeontological analysis and to compare and calibrate results for calcareous nannofossils with existing magnetostratigraphic and other biostratigraphic data. The calcareous nannofossils assemblage was dominated by the genera Watznaueria, Cyclagelosphaera, Nannoconus, Conusphaera and Polycostella.
Several nannofosil bioevents were recorded on the basic of the distibution of stratigraphycally important taxa, including zonal and subzonal markers. Based on the lowest occurrences (LO) of M. chiastius, N. globulus minor, N. wintereri, N. steinmanii minor, N. steinmannii steinmannii, N. kamptneri minor and N. kamprneri kamptneri, two nannofossil subzones (NJT 15b, NJT 17a) and two nannofossil zones (NJT 16, NK-1) were recognized.
The paper introduce new palaeoecological data based on geochemical analysis and macrofauna occurrences.