The Magnitude and Duration of Late Ordovician–Early Silurian Glaciation

Abstract

Carbonate isotopes reveal a link between past ocean temperatures and mass extinction.

Climate change and the selective signature of the Late Ordovician mass extinction

“…Notably, percent truncation was also a moderately important determinant of extinction risk during the early Katian interval. This pattern could reflect genuine extinctions due to sea level fall and habitat loss accompanying initial growth of midsized ice sheets in late Katian time (5,49). Alternatively, the pattern could be attributable to Signor-Lipps backsmearing of late Katian extinctions combined with removal of late Katian strata by erosion following the much larger end-Katian glacioeustatic regression.…”

“…The primary pulse of extinction near the Katian/Hirnantian stage boundary closely coincided with the rapid growth of south polar ice sheets on Gondwana (1)(2)(3)(4). Expansion of continental ice sheets was accompanied by substantial cooling of the tropical oceans (5, 6), a major perturbation of the global carbon cycle (7)(8)(9) and a large drop in eustatic sea level (2,5,10,11), which drained the vast cratonic seaways that characterized the Late Ordovician world (12). Extinction rates were particularly high around the tropical paleocontinent of Laurentia (13) where retreat of cratonic seas drove a sharp reduction in the area of preserved sedimentary rock between Katian and Hirnantian time (Fig.…”

Evolution of Neoproterozoic Wonoka–Shuram Anomaly-aged carbonates: Evidence from clumped isotope paleothermometry

“…Clumped isotope-derived temperatures can be combined with ␦ 18 O carb to uniquely determine ␦ 18 O w through application of an appropriate carbonate-water oxygen isotope fractionation factor (Kim and O'Neil, 1997;Vasconcelos et al, 2005). The tool has been used for a range of applications including the study of primary and diagenetic processes in terrestrial and marine samples of a wide range of ages (Came et al, 2007;Affek et al, 2008;Dennis and Schrag, 2010;Eagle et al, 2010Eagle et al, , 2011Eagle et al, , 2013Passey et al, 2010;Tripati et al, 2010Tripati et al, , 2014Bristow et al, 2011;Ferry et al, 2011;Finnegan et al, 2011;Huntington et al, 2011;Keating-Bitonti et al, 2011;Loyd et al, 2012aLoyd et al, , 2013aLoyd et al, , 2014Passey and Henkes, 2012;Swanson et al, 2012;Dale et al, 2014).…”

Biogeographic and bathymetric determinants of brachiopod extinction and survival during the Late Ordovician mass extinction

“…Major extinction pulses occurred at the boundary between the Katian and Hirnantian stages, and in the mid-Hirnantian (at the base of the Metabolograptus persculptus graptolite Biozone) [3,4]. Both these boundaries are associated with major climatic and oceanographic transitions: the former with global cooling, expansion of south polar ice sheets and falling sea levels, and the latter with warming, melting of ice sheets and continental flooding [3][4][5][6][7][8][9].…”