Ancient plants 'frozen in time' by space impacts (BBC)

[eppur_se_muova]

By Paul Rincon
Science editor, BBC News website

Ancient plant material has been preserved in the glass formed by asteroids hitting the Earth, scientists report.

The "frozen in aspic" appearance of what are apparently fragments of grass is spectacular enough.

But a team writing in Geology journal says that delicate organic chemicals have also been conserved inside.

Incredibly, the searing heat generated by the impacts was responsible for the remarkable preservation.

The findings could even point to a new way of searching for past life on Mars.
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more: http://www.bbc.com/news/science-environment-27075508
http://geology.gsapubs.org/content/early/2014/04/14/G35343.1.abstract



The "delicate organic compounds" mentioned in the article are polyaromatic hydrocarbons, commonly produced in soot, and the result of thermal decomposition of carbon-containing material. Some of the other conclusions in the article may be open to question as well.

[Judi Lynn]

1. Impact glass stores biodata for millions of years

Impact glass stores biodata for millions of years
13 hours ago

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists exploring large fields of impact glass in Argentina suggest that what happened on Earth might well have happened on Mars millions of years ago. Martian impact glass could hold traces of organic compounds.
Asteroid and comet impacts can cause widespread ecological havoc, killing off plants and animals on regional or even global scales. But new research from Brown University shows that impacts can also preserve the signatures of ancient life at the time of an impact.

A research team led by Brown geologist Pete Schultz has found fragments of leaves and preserved organic compounds lodged inside glass created by a several ancient impacts in Argentina. The material could provide a snapshot of environmental conditions at the time of those impacts. The find also suggests that impact glasses could be a good place to look for signs of ancient life on Mars.

The work is published in the latest issue of Geology magazine.

The scorching heat produced by asteroid or comet impacts can melt tons of soil and rock, some of which forms glass as it cools. The soil of eastern Argentina, south of Buenos Aires, is rife with impact glass created by at least seven different impacts that occurred between 6,000 and 9 million years ago, according to Schultz. One of those impacts, dated to around 3 million years ago, coincides with the disappearance of 35 animal genera, as reported in the journal Science a few years back.

More:
http://phys.org/news/2014-04-impact-glass-biodata-millions-years.html#jCp