Upper Tithonian-Valanginian (Upper Jurassic-Lower Cretaceous) dinoflagellate cyst stratigraphy of the western Mediterranean

Abstract

This study focuses on the qualitative dinoflagellate cyst distribution in the Upper Tithonian-Valanginian rocks of the western Mediterranean. Results are presented of research on the ammonite controlled pelagic Rı́o Argos succession near Caravaca (SE Spain) which are integrated with information from calibrated sections in southeast France and Switzerland. The ammonite framework permitted determination of contemporaneous first and last occurrences of dinoflagellate cyst taxa in the three areas. Mainly based on these biostratigraphic events, four successive dinoflagellate cyst zones are defined and identified in the Upper Tithonian-Valanginian succession of the western Mediterranean. The established zonation has potential for world-wide application. In addition, a high-resolution zonation, described as a suite of subzones, is established based on seven successive shifts in the dinoflagellate cyst development of the Upper Berriasian-Valanginian in the Rı́o Argos succession exclusively. These local palaeoecological changes are considered to reflect palaeoenvironmental and/or climatic changes of a regional, interregional or global nature.