Sulfur Isotopic Systematics in ALH84001. Open- and Closed-System Behavior of Sulfur in a Martian Hydrothermal System
Abstract
On the basis of preliminary calculations and sulfur isotopic measurements on pyrite in ALH84001, the system represented by ALH84001 is found to be open to SO4(-2). The rate of sulfate reduction is thus much slower than the rate SO4(-2) is being supplied to the system. Under this scenario, if the solutions precipitating pyrite have a delta S(34) of approximately 0, the pyrite should be enriched in the light sulfur isotope. This is clearly not consistent with the Si isotopic systematics in ALH84001. Only three scenarios are possible: the pyrite did not precipitate during biogenic activity; the solutions precipitating carbonate and pyrite are highly enriched in the heavy sulfur isotope; and biogenic activity is not recorded in ALH84001.
- Publication:
-
Lunar and Planetary Science Conference
- Pub Date:
- March 1997
- Bibcode:
- 1997LPI....28.1289S
- Keywords:
-
- Mars Surface;
- Sulfur Isotopes;
- Pyrites;
- Temperature Dependence;
- Sulfates;
- Biogeny;
- Hydrogen Sulfide;
- Carbonates;
- Bacteria;
- Lunar and Planetary Exploration;
- ISOTOPES: SULFUR;
- SYSTEMS: HYDROTHERMAL