This is one of 60 micrometeorites extracted from 2.7 billion year old limestone, from the Pilbara region in Western Australia. These micrometeorites consist of iron oxide minerals that formed when dust particles of meteoritic iron metal were oxidised as they entered Earth's atmosphere, indicating that the ancient upper atmosphere was surprisingly oxygen-rich.
Very interesting! Especially considering the theories behind the starting point where life went from anaerobic to aerobic respiration.
I wonder if the models will have to be redrawn. What caused that methane layer to dissipate? What introduced that oxygen-heavy layer, if it wasn’t CO2 respiration from new upstart life?
“Dr Tomkins explained that the new results suggest the Earth at this time may have had a layered atmosphere with little vertical mixing, and higher levels of oxygen in the upper atmosphere produced by the breakdown of CO 2 by ultraviolet light.
“A possible explanation for this layered atmosphere might have involved a methane haze layer at middle levels of the atmosphere. The methane in such a layer would absorb UV light, releasing heat and creating a warm zone in the atmosphere that would inhibit vertical mixing,” Dr Tomkins said.”
This changes a lot of what we thought we knew. It doesn’t negate earlier findings so much as it suggests more information and has implications in both abiogenesis and the search for life elsewhere in the Universe.
O2 would be heavier than CH4. So (1) what keeps it in the upper atmosphere rather than the lower; (2) why wouldn’t the methane burn at the first spark?
Or maybe the methane/lightning/life theory is bogus.
Stanley Miller, call your office.
That there’s some OLD dirt!