LIQUID WATER IN SEDIMENTS AT GALE CRATER MARS CREATED ENVIRONMENTS THAT WERE LIKELY HABITABLE AND SAMPLED BROAD BASIN-WIDE HYDROLOGIC SYSTEMS. HOWEVER MANY QUESTIONS REMAIN REGARDING THESE ENVIRONMENTS AND THE CHARACTERISTICS OF THE FLUIDS (E.G. PH WATER: ROCK RATIO DURATION OF AQUEOUS ALTERATION SOLUTION COMPOSITION TEMPERATURE AND OXIDATION STATE) THAT GENERATED THEM. MEASUREMENTS TAKEN BY THE MARS SCIENCE LABORATORY CURIOSITY OF ALTERED MATERIAL IN FRACTURE ZONES CAN HELP CONSTRAIN THESE AQUEOUS CONDITIONS. BECAUSE THE ALTERED MATERIAL WITHIN THE FRACTURE ZONES IS CLOSELY ASSOCIATED WITH NEARBY PARENT MATERIAL FROM WHICH IT FORMED CHANGES DUE TO FLUID INTERACTIONS CAN BE QUANTIFIED. REACTIVE TRANSPORT MODELING CAN THEN BE USED TO YIELD QUANTITATIVE CONSTRAINTS ON AQUEOUS PARAMETERS SUCH AS PH WATER: ROCK RATIO DURATION OF AQUEOUS ALTERATION SOLUTION COMPOSITION TEMPERATURE AND OXIDATION STATE IF APPROPRIATE KINETIC AND SOLUBILITY DATA ARE AVAILABLE.