April 20, 2014
Plant Material Stored In Impact Glass Could Reveal Much About Ancient Earth, Mars
redOrbit Staff & Wire Reports - Your Universe Online
The discovery of biodata encapsulated in molten glass resulting from asteroid and comet impacts millions of years ago not only provides information about the climate and life forms of the ancient Earth, but has also led to hopes that similar preserved organic compounds will be discovered on Mars.
Fragments of leaves and other organic compounds were found lodged inside glass created by ancient impacts in Argentina by Brown University geologist Pete Schultz and his colleagues, and that material could provide them with a snapshot of the environmental conditions that existed when those impacts originally occurred thousands or millions of years ago.
Writing in the most recent edition of the journal Geology, they explained that the immense heat produced by the asteroid or comet impacts was capable of melting copious amounts of rock and soil, some of which formed glass as it cooled. Regions of eastern Argentina are home to impact glass resulting from at least seven different impacts that took place between 6,000 and 9 million years ago, Schultz explained in a statement Friday.
“We know these were major impacts because of the shocked minerals trapped inside with plant materials. These glasses are present in different layers of sediment throughout an area about the size of Texas,” he said.
Glass associated with two impacts – one from 3 million years ago, and another from 9 million years ago – was found to contain exceptionally well preserved plant matter, Schultz and his colleagues said in a statement.
Those plant material contained in the glass samples included centimeter-size leaf fragments, some structures of which were completely intact, and some samples featured batches of vein-like structures unearthed closely resembling pampas grass, a modern species readily found throughout this region of Argentina.
Furthermore, chemical analysis of these samples also revealed the presence of organic hydrocarbons, which the researchers explain serve as the chemical signatures of living matter. Through laboratory experiments, Schultz’s team was able to determine that plant material was likely preserved when the impact glass encasing them was quickly heated to temperatures over 1,500 degrees Celsius.
Schultz explained that the water in the exterior layers of the leaves apparently insulated the inner layers, keeping them from becoming damaged. He compared the process to deep frying, in that the outside “fries up quickly” but the inner part “takes much longer to cook.”
The study could have an effect on the search for signs of past life on Mars as well. As the researchers explain, if impact glass is capable of preserving biodata here on Earth, it is certainly possible that it could have done so on Mars as well. Helping the cause is the similarity between the soil found in Argentina and on the Red Planet.
“Impact glass may be where the 4 billion-year-old signs of life are hiding. On Mars they’re probably not going to come out screaming in the form of a plant, but we may find traces of organic compounds, which would be really exciting,” noted Schultz, who was assisted by experts from the Georgia Department of Transportation Office of Materials and Testing, Jacobs Technology in Houston, and the National University of La Pampa in Argentina.