Influence of climate, sea-level changes and tectonics on ichnoassemblages distribution in a carbonate-dominated, deep-marine environment (Upper Paleocene, Zumaya section)

A detailed bed-by-bed ichnological analysis of the Paleocene of the Zumaya section (northern Spain) revealed the presence of eight different ichnoassemblages. Four different sets of beds were determined using both ichnological and sedimentological features. Their distribution throughout the section can be compared to the sedimentary trends based on geochemical and sedimentological data, in order to better understand the ecological significance of the ichnoassemblages and to determine the most important parameters that drove the environmental evolution of the area. Significantly, there is a marked relationship between the distribution of the ichnoassemblages and the recorded variations in the rate of sedimentation in both the background (hemipelagic limestones) and the episodic sediments (calcareous and siliciclastic turbidites). However, some ichnoassemblages (e.g. ichnoassemblage 4a: Planolites beverleyensis and ichnoassemblage 2b: ?Palaeophycus tubularis) while clearly lithofacies-related also appear to be controlled by other parameters, such as the amount of benthic food introduced into the basin from shallow-water areas.