DINOCYSTS AND THE PALEOENVIRONMENTAL INTERPRETATION OF NONMARINE SEDIMENTS - AN EXAMPLE FROM THE WEALDEN OF THE ISLE-OF-WIGHT (LOWER CRETACEOUS, SOUTHERN ENGLAND)

The results of a high-resolution palynofacies study of a short vertica l sequence (c. 11 cm) of the Wealden Vectis Formation (Lower Cretaceou s, Isle of Wight, Southern England), provide detailed evidence to asse ss the salinity tolerance of two species of dinocyst: Vesperopsis frag ilis and Corculodinium uniconicum. Analysis of the fluctuating relativ e abundances of the particulate palynomacerals in combination with ost racod studies and sedimentological information indicate that these din ocyst taxa were euryhaline in nature. V. fragilis is interpreted as be ing produced by an opportunistic euryhaline dinoflagellate adapted to life in salinity-stressed environments and capable of reproducing rapi dly in large numbers to capitalize on temporarily increased nutrient a vailability. (C) 1995 Academic Press Limited.