Estimation of environmental paleogradient values based on presence/absence data: a case study using benthic foraminifera for paleodepth estimation

Objective criteria are used to eliminate non-overlapping variates along the gradient (e.g., species whose distributions do not overlap in living individuals but are mixed in samples of empty tests). This is important in estimating paleogradients because mixing of non-overlapping variates is a common effect due to post-mortem transport, bioturbation, or sediment reworking. The new method is calibrated for depth estimation using living symbiont-bearing benthic foraminifera and empty tests from the NW Pacific, and living smaller benthic foraminifera from the shelf and continental slope of Senegal. This approach is then successfully applied for paleodepth estimation of a lower to middle Miocene transect in the Styrian Basin (Austria), where plankton/benthos ratios of foraminifera yield poor depth estimations.