The Late Devonian (Frasnian/Famenian) mass extinction: a proposed test of the glaciation hypothesis

In this paper it is agued that Late Frasnian global cooling was the first step in the onset of the Late Paleozoic Ice Age, and that a Late Frasnian glaciation existed that was analogous to the early Oligocene (Oi-1) glaciation that took place in the first step of global cooling in the onset of the Cenozoic Ice Age. It is here proposed that definitive sedimentological evidence for the existence of Late Frasnian glaciation, like the Oi-1 glaciation, would be the discovery of ice-rafted debris in marine sediments of Late Frasnian age similar to the ice-rafted debris found in Oi-1 marine sediments (Zachos et al., 1992; Ehrmann and Mackensen, 1992). Rather than metre- to decimetre-sized ice-rafted debris, a search should be initiated for the presence of sand-sized (>250 mu m) ice-rafted debris in Frasnian marine strata located offshore from the main Gondwana landmass, and dated to the Late rhenana Conodont Zone and/or to the linguiformis-Early triangularis conodont zonal interval where the extinctions and sharp drops in sea-surface temperature occurred (Joachimski and Buggisch, 2002).