2001 Annual Science Report
Arizona State University Reporting | JUL 2000 – JUN 2001
Cosmochemistry of Carbonaceous Meteorites
Cosmochemistry of Carbonaceous Meteorites (dm)
In this project we seek to understand the origin of pre-biotic organic molecules in carbonaceous chondrite meteorites and the origin and distribution of water (and other volatiles) on Mars.
In the past year we have had the unexpected pleasure of being able to study in detail a new, exciting meteorite fall, the Tagish Lake carbonaceous chondrite. We have examined the organic and inorganic inventory of this new, very primitive meteorite, leading to two published extended abstracts.
In the past year, we published a cover article in Geophysical Research Letters on the origin and evolution of water on Mars, based on an analysis of hydrous minerals in martian meteorite QUE 94201. In this work, we found the minerals to contain a mixture of water from two different sources, as delineated by their D/H ratios. First, the minerals contain primary “magmatic” water from the martian interior, with a D/H value ~twice terrestrial. This water was partially equilibrated with martian “meteoric” water, with a D/H value ~5 times terrestrial, as previously measured in the martian atmosphere. The big discovery here was the D/H value of magmatic water, which is much higher than previously assumed. This result has implications for the history of water on Mars, which probably involved a two-stage evolution, where early hydrodynamic escape was followed by Jeans escape of the atmosphere, a process that continues to the present day. In addition, the data imply that there may be ~2-3 times more water in the martian crust today than previously thought, which bodes well for martian biological potential.
PROJECT MEMBERS:Laurie Leshin
RELATED OBJECTIVES:Objective 1.0
Determine whether the atmosphere of the early Earth, hydrothermal systems or exogenous matter were significant sources of organic matter.
Describe the sequences of causes and effects associated with the development of Earth's early biosphere and the global environment.
Search for evidence of ancient climates, extinct life and potential habitats for extant life on Mars.
Determine the presence of life's chemical precursors and potential habitats for life in the outer solar system.
Determine (theoretically and empirically) the ultimate outcome of the planet-forming process around other stars, especially the habitable ones.
Define climatological and geological effects upon the limits of habitable zones around the Sun and other stars to help define the frequency of habitable planets in the universe.