Palaeoenvironmental changes across the Mid- and latest Maastrichtian events: Planktic foraminiferal inference from the Elles section (central Tunisia)

Based on quantitative changes in the Maastrichtian planktic foraminiferal species distribution patterns from the Elles section (central Tunisia), & delta;13C, & delta;18O-based palaeotemperature and inferred proxies (species diversity, ecological associations, and depth ranking), the palaeoenvironment is inferred. Based on Constrained Clustering and corroborated by Non-metric Multidimensional Scaling (NMDS), four statistically significant intervals are identified. Interval 1 (lower-middle part of CF5 Zone) is marked by a warm, oligotrophic, stable, and well-stratified upper water column. Interval 2 (upper part of CF5 Zone), here designated as the pre-Mid-Maastrichtian Event (MME) event, is marked by stressed, warmer, moderately mesotrophic, and weakly stratified surface waters with an unstable upper water column. Interval 3 (CF4 Zone) encompasses the MME and is marked by warm, stable, mesotrophic surface waters with a moderately well-stratified upper water column. The upper part of Interval 3, designated as post-MME, is also marked by mesotrophic conditions, but with increased surface water warming, unstable and stressed conditions. Interval 4 (CF3-CF1 zones) shows the effects of the Indian Deccan volcanism, and is marked by warmer surface waters, mesotrophic, unstable, stressed environmental conditions, with a weakly-stratified upper water column. Maastrichtian palaeoenvironmental analyses from the Elles section (central Tunisia) was carried outPlanktic foraminifera species distribution, diversity proxies, & delta;13C and & delta;18O-based palaeotemperatures were used.Four statistically significant intervals are notedInterval 1 reflects stable, warm, oligotrophic and a well stratified upper water column.Interval 2, pre-Mid-Maastrichtian Event (MME), is marked by unstable, warmer, oligotrophic and a weakly-stratified upper water column.Interval 3, MME, is marked by cool, stable, mesotrophic and moderately well-stratified upper water column.Interval 4 is marked by warm, mesotrophic, unstable, weakly-stratified and stressed conditions.image