Cretaceous Research 22, 3, 333-351 (2001)
Faunal dynamics of juvenile gastropods and associated organisms across the Valanginian transgression-regression cycle in central Poland.

Kaim, A.

Abstract. The Valanginian fossil assemblages at Wwa in central Poland are dominated by juvenile gastropods with planktotrophic, mostly pelagic larvae, thus largely independent of local bottom environment in their distribution. The gastropod-dominated associations show a species turnover pattern surprisingly consisting with eustatic cycle and changes in biogeographic provincionalism, strongly expressed also in the distribution of ammonites. The Valanginian sea expanded to central Poland from the north, bringing cold waters with boreal faunas and at the deepening sea bottom the diversity of benthonic macroorganisms decreased. During the early Late Valanginian highstand, the seaway connecting north European with the Carpathian ocean expanded enough to allow migration the Tethys organisms to central Poland. In the late Late Valanginian this eustatic trend reversed and Boreal faunas replaced again those from the Tethys. The isotope record in benthonic foraminifer tests suggests that despite the sea level changes the bottom water temperatures remained relatively stable.