Palynology of the Middle Jurassic Lower Graben Sand Formation of the U-1 well, Danish Central Trough

Abstract

Twentyone sidewall core samples from the lower 56 metres of the Lower Graben Sand Formation in the U-1 well are described with respect to their kerogen content and microflora in order to gain a better understanding of the depositional environment and the age relations. Based on e.g. the inconsistent dinoflagellate cyst occurrences, marginal marine conditions are concluded. The dinoflagellate cysts Pareodinia prolongata, Acanthaulax senta, Scriniodinium crystallinum, Energlynia acollaris, Wanaea thysanota and Hystrichogonyaulax cladophora and the recovered palynomorph assemblage in general permit an age determination as follows: 21 m Callovian undifferentiated, 7.9 m latest Middle Callovian - earliest Late Callovian, 6.1 m latest Late Callovian and 21 m latest Late Callovian? - earliest Early Oxfordian.