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Raining lead around 250mya : a smoking gun for an Australian impact origin of the Permian Extinction.
 

Summary: 1
Raining lead around 250mya : a smoking gun for an Australian
impact origin of the Permian Extinction.
(2170 words)
Jim Standard and C. Austen Angell
Department of Chemistry and Biochemistry, Arizona State University,
Tempe, AZ 85287
Recent documentation of extreme atmosheric sulfur and methane coincident with
the vast Permo-Triassic (P-T) extinction allows interpretation of a 40-year old
report of metallic lead microspheres, with aerodynamic tails, in the graphite-loaded
fluvial strata of early Triassic sandstones in the Sydney basin. While climate change
and flood basalt volcanism could explain the atmospheric anomalies, only an
extraterrestrial impact in a lead sulfide mineralized zone could explain the
occurrence of native lead in this form. Using thermodynamic arguments, flow
directional data for the sandstones, and Tasmanian mineralization data for the lead
origin, we deduce an impact site in Bass Strait, where ring-like gravitational
anomalies, and a provocative "interior basin" structure complete with melt-rocks at
2 km depth (as in the Cretaceous-Tertiary (K-T) boundary Chixculub crater) are
found in gravity survey and oil drilling maps/reports. We predict the co-occurrence
of lead tears and graphite elsewhere, possibly in Antarctic sandstones.

  

Source: Angell, C. Austen - Department of Chemistry and Biochemistry, Arizona State University

 

Collections: Materials Science; Chemistry