The later Eocene transgressions in southern Australia

Abstract

Correlations based mostly on planktonic foraminiferal assemblages indicate four continent-wide transgressions: two in the late Middle Eocene (high Zone PI2; near Zone P14/P15 boundary) and two in the Late Eocene (near top Zone P15; low Zone P17). The first (Wilson Bluff) is part of the Indo-Pacific Khirthar Transgression at the boundary between the Laramide and Himalayan global tectonic regimes; the Khirthar was an ‘immediate“ response to renewed seafloor spreading (geomagnetic Anomaly 19) after India/Asia collision. However, the later transgressions were more widespread in this region. Although data are patchy and correlations are somewhat strained, there is some evidence that transgressions fall between lowstands in the incomplete global curve and that they are coeval with isotopic and biological (oceanic, neritic, continental) evidence for warming. The later Eocene as a whole marks a significant intervening reversal of the global climatic deterioration that occurred across the Early/Middle Eocene and E...