816,000 Years Old - Random Extraterrestrial Event
Just over three-quarters of a million years ago a stony meteorite (rich in silicate minerals & estimated to be 50 metres or less across) crashed into south west Tasmania near Mt Darwin.
Instantaneously the impact created a crater 1.3 kilometres across & 230 metres deep, melted thousands of cubic metres of rock & sprayed fragments of this melted rock “Darwin Glass” out over an area of about 400 square kilometres.
Most of the meteorite vaporised on impact, its presence only evident now as anomalously high concentrations of nickel, cobalt, chromium magnesium & iron in the glass fragments (the result of the mixing vapours with molten glass on impact.)
The rocks in the target area belonged mainly to two formations of quartzite & slate of the saurian age. Darwin impactites can be extremely variable in shape, some strangely twisted with stalactitic folds, others more or less a shapeless frothy mass.
The colour also varies from pale green through to an intense deep green almost black. Air holes, minute to 3mm in diameter, are ever-present.