Dinoflagellate and Acritarch assemblages from the late Bathonian to early Oxfordian of Montagne Crussol, Rhone valley, southern France

Abstract

Diverse and well‐preserved dinoflagellate cyst and acritarch assemblages were recovered from late Bathonian to early Oxfordian strata of Mt. Crussol, southern France. Two distinct microplank‐ton associations are recognized based on the stratigraphic ranges of 89 identified species, together with frequency distribution data of the most abundant taxa. The older, termed the Ctenidodinium combazii—Cleistosphaeridium varispinosum association, comprises the late Bathonian‐early Callovian strata of Mt. Crussol, while the younger Compositosphaeridium polonicum‐Sen‐tusidinium pilosum association characterizes the ?late Callovian‐early Oxfordian interval. The palynological data suggest a hiatus and/or a pronounced stratal condensation spanning the middle Callovian and possibly part of the upper Callovian in the study section. Trends in the geographic distribution of selected species are discussed based on comparisons of the marine microfloras from Mt. Crussol and other parts of the Tethyan Realm with assemblages recorded from contemporaneous strata of the Sub‐Boreal and Boreal Realm.