Sedimentology of the Bajocian Fuglunda Member at Eriksdal, Scania, southern Sweden

Abstract: The Bajocian Fuglunda Member of Eriksdal consists mostly of sand, silt and coal arranged in cycles (2-4m). Each cycle generally starts with organic-rich heteroliths at the base and further up ripple-drift cross laminated and horizontally laminated fine sand follow. The coal seams at the top of the cycles are of minor thickness. Signs of soil formation occur as coalified rootlets reaching down from the seams, and as soil horizons with upper erosive boundaries. Evidence of lacustrine as well as brackish and marine conditions are represented in the strata. The coal seams contain a flora of fresh water plants, whereas pyrite nodules, Diplocraterion and calcareous foraminifera are characteristics of brackish or marine conditions. The different sediments were divided into two populations interpreted as originating from mainly river generated and beach foreshore processes. The cyclic arrangement of the present sediments and their characteristics point at a lower delta plain environment, where sediments were deposited from the distributaries into the interdistributary bays. Fluctuations in sea-level, possibly due to variations in the campaction of underlying sediments, periodically exposed the bays to basinal processes.