GLOBAL CLIMATIC FORCING OF DEEP-SEA BENTHIC FORAMINIFERAL TEST SIZE DURING THE PAST 120 MY

Stratigraphic distribution of the maximum diameter of the largest deep -water (>1500 m eater depths) calcareous trochospiral benthic foramini feral tests in samples representing the past 120 m.y. shows that avera ge values of the maximum diameter have doubled since Early Cretaceous time, Fluctuations in test size show six minima and six maxima. It is significant that the fluctuations correspond to changes in global clim ate and in deep-water dissolved oxygen conditions. This latter synchro nism indicates that deep-sea foraminiferal test size was likely contro lled by fluctuations in the level of dissolved oxygen or related facto rs in the deep ocean caused by global climatic changes.