Permo-Triassic Extinction Event

Bones of vertebrate animals were also recovered from the upper Eremouw Formation in Gordon Valley in the Queen Alexandra Range (Fig. 10.14) and from the upper Falla Formation on Mt. Kirkpatrick (Hammer et al. 1987). The Fremouw Formation in Gordon Valley actually contains foot prints of vertebrates which were described and photographed by Macdonald et al. (1991). The bones recovered by W.R. Hammer and his 

The end of the Permian Period is defined by the extinction of about 90% of all life forms that existed on the Earth at that time. This catastrophe was even more severe than the extinction event that defines the end of the Cretaceous Period which resulted from the profound environmental disturbance caused by the impact of an asteroid at Chicxulub on the Yucatan Peninsula of Mexico. The cause of the Permo-Triassic extinction could have been a dramatic fluctuation of the global climate, or of sealevel, or the impact of an asteroid or comet, or severe volcanic activity, or all of the above. 

Retallack et al. (1998) briefly reviewed the literature concerning the causes of the Permo-Triassic extinction event as an introduction to their own study to determine whether boundary clays at Graphite Peak between the Buckley and Fremouw formations contain shocked quartz and anomalously high concentrations of iridium of meteoritic origin. Although they found shocked 

In a related study, Basu et al. (2003) reported finding meteorite fragments and metalUc grains in rock samples from Graphite Peak. However, in the absence of an impact crater and other geomorphic evidence that is characteristic of impact events, the search for the causes of the Permo-Triassic extinction event continues. 

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