planktonic foraminifera response to sudden global warming in late maastrichtian, a case study from ziyarat-kola, central alborz, iran

an abrupt global warming event has been recorded in many parts of the world in sediments of latest maastrichtian age between 65.45-65.10 ma. this warm event was documented here at a section near ziyarat-kola in central alborz based on analysis of planktonic foraminifera. an unusual abundance of normally large-size species such as globotruncana arca, globigerinelloides subcarinatus, pseudoguembelina hariaensis and rugoglobigerina rugosa in small-size fraction (63-150) was recorded. a similar trend of increasing in relative abundance of some opportunist species such as guembelitria spp. was also recorded. at the same time, laeviheterohelix dentata a long ranging dominant species, decreases considerably reflecting a high stress environmental condition as warming. palynological studies show an increase in fungal spore and in thermophilic species confirming the result gained from foraminiferal analysis.