  Recent documentation of extreme atmospheric sulfur and methane contents at
the time of the vast Permo-Triassic (P-T) extinction makes it possible to
interpret an observation that has lain unnoticed in the geological literature
for 40 years. This is the finding of microscopic metallic lead tear drops in
the fluvial strata of the early Triassic sandstones that overlie Permian coal
beds and other sedimentary deposits in the Sydney basin of Australia. Elemental
lead is almost unknown in nature, so its occurrence in these graphite-loaded
sandstones is a provocative finding. While climate change and vulcanism could
explain the carbon and sulfur anomalies, the only way to account for metallic
lead aerodynamic droplets is by massive impact and vaporization of lead
mineral-containing formations. Since lead occurs geologically as the sulfide
and since lead is an easily reduced element, its occurrence in conjunction with
sulfur and carbon count anomalies suggests a bolide impact on carbon-loaded
strata in a sulfide mineral-rich region. From these clues, and from stream
cross-bedding data, we identify a probable site for the impact, in Bass Strait
between Tasmania and Victoria. A gravitational anomaly, similar to that known
at the site of the Cretacious-Tertiary (C-T) impact site, conforms with a
central uplift. The sudden compression at an Australian impact site would
provoke tension fissuring on the opposite side of a shell- structured planet,
hence is consistent with the unprecedented flood basalts initiated in Siberia
at the P-T boundary. Our interpretation requires that lead microspheres and
graphite occur together elsewhere, possibly in Antarctic sandstones.
