Palynofacies variations in a carbonate ramp system environment (Upper Muschelkalk, NE France)

Abstract

Abstract This study analyses variations in the size of black woody phytoclast and palynofacies types of shallow subtidal environments evolving to deeper subtidal environments, of latest Illyrdian-latest Fassanian age (Upper Muschelkalk). Some of the results display some discrepancies between elevated particle sizes that were supposedly deposited in a relative proximal source and the rich veryhachid palynofacies that are thought to represent distal marine environments. A case study of the succession in the Héming quarry, located in the Alsace-Lorraine trough (southwestern part of the intracratonic Germanic basin) reveals that : (1) the palynological assemblages are dominated by acritarchs belonging to micrhystridids, disaccate pollen and woody phytoclasts; (2) the abundance of phytoclasts, sporomorphs and marine groups is not correlated with lithologies; (3) the length of the processes of micrhystridids is not a useful parameter in defining palynofacies types. In carbonate ramp environments, many factors could have confused the palynological signals such as high-energy events and the water level on which the nutrient supply depended pro parte. All these factors seem to have been governed by climatic or tectono-eustatic events.