Washington, DCOrganic compounds contain carbon and hydrogen and form the building blocks of all life on Earth. By analyzing organic material and minerals in the Martian meteorite Allan Hills 84001, scientists at the Carnegie Institution's Geophysical Laboratory have shown for the first time that building blocks of life formed on Mars early in its history. Previously, scientists have thought that organic material in ALH 84001 was brought to Mars by meteorite impacts or more speculatively originated from ancient Martian microbes.
The Carnegie-led team made a comprehensive study of the ALH 84001 meteorite and compared the results with data from related rocks found on Svalbard, Norway. The Svalbard samples occur in volcanoes that erupted in a freezing Arctic climate about 1 million years agopossibly mimicking conditions on early Mars.
Organic material occurs within tiny spheres of carbonate minerals in both the Martian and Earth rocks, explained Andrew Steele, lead author of the study. We found that the organic material is closely associated with the iron oxide mineral magnetite, which is the key to understanding how these compounds formed.
The organic material in the rocks from Svalbard formed when volcanoes erupted under freezing conditions. During cooling, magnetite acted as a catalyst to form organic compounds from fluids rich in carbon dioxide (CO2) and water (H2O). This event occurred under conditions where no forms of life are likely to exist. The similar association of carbonate, magnetite and organic material in the Martian meteorite ALH 84001 is very compelling and shows that the organic material did not originate from Martian life forms but formed directly from chemical reactions within the rock. This is the first study to show that Mars is capable of forming organic compounds at all.
The organic material in the Allan Hills meteorite may have formed during two different events. The first, similar to the Svalbard sampl
|Contact: Andrew Steele|