Thermal alteration of organic matter in an impact crater and the duration of postimpact heating
- 1Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen AB24 3UE, UK
- 2Department of Planetary Sciences, University of Arizona, 1040 East 4th Street, Tucson, Arizona 85721-0077, USA
- 3Search for Extraterrestrial Intelligence (SETI) Institute, National Aeronautics and Space Administration (NASA) Ames Research Center, Moffett Field, California 94035-1000, USA
- 4Geotrack International Pty Ltd., 37 Melville Road, Brunswick West, Victoria 3055, Australia
- 5Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen AB24 3UE, UK
Abstract
The 24-km-diameter Tertiary Haughton impact structure formed in rocks that contained preexisting liquid hydrocarbons. Biomarker ratios in the hydrocarbons show a consistent pattern of variation in degree of heating across the structure. The heating reached a maximum at the crater center and is attributed to hydrothermal activity following impact. Kinetic modeling suggests a time scale of ∼5 k.y. for the heating, at a maximum temperature of 210 °C. The short time scale suggests that in moderate-sized craters, which are abundant on Mars, heating is not so extensive that fossil or extant organic matter would be obliterated.
Footnotes
-
- Accepted 1 January 2005.
- Received 15 September 2004.
- Revision received 27 December 2004.
- Geological Society of America
