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

Abstract

In this pa per it is agued that Late Frasnian global cool ing was the first step in the on set of the Late Pa leo zoic Ice Age, and that a Late Frasnian gla ci ation ex isted that was anal o gous to the early Oligocene (Oi-1) gla ci ation that took place in the first step of global cool ing in the on set of the Ce no zoic Ice Age. It is here pro posed that de fin i tive sedimentological ev i dence for the exis tence of Late Frasnian gla ci ation, like the Oi-1 gla ci ation, would be the dis cov ery of ice-rafted de bris in ma rine sed i ments of Late Frasnian age sim i lar to the ice-rafted de bris found in Oi-1 ma rine sed i ments (Zachos et al., 1992;Ehrmann and Mackensen, 1992). Rather than metre-to decimetre-sized ice-rafted de bris, a search should be ini ti ated for the pres ence of sand-sized (>250 mm) ice-rafted de bris in Frasnian ma rine strata lo cated off shore from the main Gond wana land mass, and dated to the Late rhenana Cono dont Zone and/or to the linguiformis-Early triangularis cono dont zonal in ter val where the extinc tions and sharp drops in sea-sur face tem per a ture oc curred (Joachimski and Buggisch, 2002).

Paleozoic–Mesozoic Eustatic Changes and Mass Extinctions: New Insights from Event Interpretation

“…A significant mass extinction occurred at the Frasnian/Famennian transition in the Late Devonian, and it is known as the Kellwasser event [ 44 , 75 , 76 , 77 , 78 ]. According to the reconstruction by Haq and Schutter [ 35 ], this biotic catastrophe corresponds to relatively low-magnitude fluctuations of the global sea level followed by a pronounced fall.…”

The Paleoecological Environment during the Ediacaran–Cambrian Transition in Central Guizhou Province, China: Evidence from Zn Isotopes

“…Primary producers preferentially absorb and remove light δ 66 Zn, prompting strong biological pumping in the ocean to cause positive shifts in Zn isotopes [45,139,140]. In the early Cambrian period, the cooling of the climate triggered intermittent continental glaciation in the South China Plate, which was dominated by carbonate deposits, resulting in a relative drop in sea level [141][142][143]. This process led to the erosion or exposure of the carbonate platform, and the weathering differential effect increased the proportion of carbonate karst hydrolytic input compared with that of silicate, resulting in the positive drift of δ 66 Zn value [144][145][146][147].…”

The Search for Sedimentary Evidence of Glaciation during the Frasnian/Famennian (Late Devonian) Biodiversity Crisis

“…Rather than the meter-to decimeter-sized Famennian ice-rafted debris (Fig. 4), a search should be initiated for the presence of Frasnian ice-rafted debris of mediumsized (> 250 μm) and larger sand grains and gravels with pebbles, similar to the ice-rafted debris found in Oi-1 marine sediments (Zachos et al 1992, Ehrmann andMackensen 1992) That search should target Frasnian marine strata correlated to the Lower and/or Upper Kellwasser horizons where late Frasnian extinctions and sharp drops in sea-surface temperature occurred (for discussion see McGhee 2013McGhee , 2014. Absence of evidence is not evidence of absence, as even in the Oi-1 glaciation ice-rafted debris is not universally found in the sedimentary record: for example, ice-rafted sand and gravel is present on the Kerguelen Plateau in the Indian Ocean but absent on the Maud Rise in the Atlantic Ocean (Ehrmann and Mackensen, 1992).…”

“…The cause of the Late Devonian (Frasnian/Famennian) biodiversity crisis remains controversial. Over 36 years of amassed empirical biological data have been used to argue for a causal link between global cooling and the Frasnian/Famennian extinctions (for a review of the data see McGhee 2013McGhee , 2014. In particular, glaciation produced by global cooling has long been proposed to have been a trigger for the Frasnian/Famennian extinctions (Caputo and Crowell 1985, Caputo 1985, Streel et al 2000a, 2000b, Isaacson et al 2008.…”