The onset of the permo-carboniferous glaciation: Reconciling global stratigraphic evidence with biogenic apatite δ~(18) O records in the late visean

摘要

The δ~(18)O values of phosphatic microfossils recovered from NW Ireland are used to determine the timing and magnitude of cooling associated with the onset of the Carboniferous glaciation. icrofossil fish δ~(18)Oapatite demonstrates a +2.4‰ (V-SMOW) shift, which, once corrected for δ~(18)O seawater changes owing to evolving ice volumes, equates to an approximate 4.5 °C reduction in equatorial sea surface temperature between the earliest Asbian and the mid- Brigantian (late Visean). Both conodont and microfossil fish δ~(18)O apatite indicate stabilization of an 'icehouse' climate during the Brigantian and into the Serpukhovian. Substantial late Visean cooling identified herein is in good agreement with global glacioeustatic records