PERCHLORATE HAS BEEN DETECTED ON MARS IN CONCENTRATIONS AND AT RATIOS TO OTHER ANIONS THAT ARE MUCH HIGHER THAN NORMALLY DETECTED IN TERRESTRIAL SYSTEMS AND OTHER EXTRATERRESTRIAL SAMPLES. HOWEVER THE PRESENCE OF CHLORATE ON MARS IS UNCERTAIN AND IF PRESENT MUST OCCUR AT LOWER CONCENTRATIONS THAN PERCHLORATE. THIS IS CONTRARY TO TERRESTRIAL SYSTEMS LUNAR REGOLITH AND METEORITES WHICH REFLECT A ROUGHLY EQUIMOLAR RATIO OF CHLORATE TO PERCHLORATE WITH ONLY ONE KNOWN EXCEPTION: THE ANTARCTICA DRY VALLEY SOILS. ANTARCTICA DRY VALLEY SOILS HAVE CHLORATE TO PERCHLORATE RATIOS GREATLY REDUCED (1/10-1/100TH) TO OTHER HYPER-ARID LOCATIONS ON EARTH (E.G. ATACAMA) AND AT A RATIO SIMILAR TO THAT PREDICTED ON MARS. FURTHERMORE AN INVESTIGATION INTO THE 37CL/35CL VALUES OF HCL PRODUCED FROM SURFACE MATERIAL FROM GALE CRATER HAVE REPORTED A LARGE VARIATION OF LIGHT 37CL/35CL VALUES POTENTIALLY EXPLAINED BY TWO MODELS: (1) THE PRODUCTION OF OXYCHLORINE COMPOUNDS FROM VOLCANIC GAS EMISSIONS AND (2) THE REDUCTION OF PERCHLORATE TO CHLORIDE. WE HYPOTHESIZE THAT CHLORATE NOT PERCHLORATE IS THE OXYCHLORINE SPECIES THAT IS REDUCED TO CHLORIDE PRODUCING THE LIGHT 37CL/35CL VALUES. WE ALSO HYPOTHESIZE THAT THE LOW RATIO IN ANTARCTICA DRY VALLEY SOILS AND MARTIAN SOILS IS LIKELY DUE TO REACTIONS WITH FE MINERALS. ALL KNOWN PERCHLORATE PRODUCTION MECHANISMS PRODUCE CHLORATE AND PERCHLORATE AT LEAST ON AN EQUAL MOLAR BASIS AND IN MANY CASES PRODUCE CHLORATE WITH YIELDS ORDERS OF MAGNITUDE HIGHER THAN PERCHLORATE. THEREFORE IT CAN BE HYPOTHESIZED THAT PERCHLORATE AND CHLORATE WERE PRODUCED ON MARS WITH AT LEAST EQUIVALENT ABUNDANCE AND NEAR SURFACE REACTIONS TRANSFORMED THE CHLORATE REDUCING THE CHLORATE TO PERCHLORATE RATIO. THE OVERALL OBJECTIVE OF THIS PROJECT IS TO DETERMINE IF THE LOW RATIO OF CHLORATE TO PERCHLORATE ON MARS IS DUE TO POST DEPOSITIONAL ABIOTIC PROCESSING. WE PROPOSE TO DETERMINE: (1) WHAT PROCESSES COULD CAUSE LOW RATIOS OF CHLORATE TO PERCHLORATE IN MARTIAN SOILS AND (2) WHAT CAUSES THE DEPLETED 37CL/35CL VALUES REPORTED AT GALE CRATER. DEFINING THE POTENTIAL REDUCTION OF CHLORATE ON MARS WILL CONSTRAIN: (1) THE VARIATION IN LIGHT 37CL/35CL DETECTED IN HCL AT GALE CRATER (2) THE GEOCHEMICAL SURFACE REACTIONS THAT PRODUCED AND EVOLVED THE FOSSIL RELIC OF OXYCHLORINE COMPOUNDS ON MARS ELUCIDATING PAST AND PRESENT MARTIAN SURFACE CONDITIONS AND (3) THE DELINEATION OF POTENTIAL REACTIONS THAT REDUCE NITRATE TO (PER)CHLORATE RATIOS IN MARTIAN SOILS. THE LOSS OF CHLORATE WOULD ALSO DICTATE CONDITIONS WHICH WOULD HAVE REDUCED NITRATE. THE POTENTIAL LOSS OF NITRATE WOULD HAVE IMPORTANT IMPLICATIONS FOR UNDERSTANDING NITROGEN CYCLING. RESULTS OF THIS STUDY WILL INCREASE OUR UNDERSTANDING OF THE PROCESSES THAT COULD POTENTIALLY DOMINATE THE SURFACE MARTIAN GEOCHEMICAL SYSTEM AND BE A BASELINE TO GUIDE FUTURE STUDIES ON MARTIAN ATMOSPHERE SURFACE REACTIONS AND THE SEARCH FOR LIFE. THIS PROJECT WILL AIM AT INCREASING NASA S MISSION TO FURTHER UNDERSTANDING OF A SOLAR SYSTEM BODY AND TO UNDERSTAND THE ORIGINS AND EVOLUTION OF SURFACE PROCESSES IN SOILS ON MARS.