THIS IS A PROPOSAL REQUESTING THREE YEARS OF FUNDING TO CARRY OUT A STUDY OF THE STRUCTURE TEXTURE COMPOSITION AND DISTRIBUTION OF PHOSPHATES IN MARTIAN METEORITES. THE PRIMARY GOALS OF THIS STUDY ARE 1) GAIN A BETTER UNDERSTANDING OF ELEMENTAL PARTITIONING BETWEEN PHOSPHATES IN TWO-PHOSPHATE IGNEOUS SYSTEMS SO THAT PHOSPHATES CAN EVENTUALLY BE USED AS A PETROGENETIC TOOL FOR STUDYINGMARTIAN METEORITES; 2) GAIN A BETTER UNDERSTANDING OF THE HYDROGEN ABUNDANCES OF WHITLOCKITE/MERRILLITE THROUGH SINGLE-CRYSTAL XRAY DIFFRACTION ANALYSIS TO DETERMINE WHAT INFORMATION THESE MINERALS CAN PROVIDE REGARDING THE ROLE OF WATER IN MARTIAN MAGMATIC SYSTEMS; 3) BUILD A COMPREHENSIVE DATASET OF PHOSPHATES FROM MARTIAN METEORITES THAT INCLUDES MAJOR MINOR AND TRACE ELEMENT CHEMISTRY AS WELL AS TEXTURAL ASSOCIATIONS. THE PHOSPHATE ION IS IMPORTANT FOR MANY REASONS. FROM A PETROLOGIC STANDPOINT THE PHOSPHATE ION BEHAVES INCOMPATIBLY DURING CRYSTALLIZATION AND THE PHOSPHATE MINERALS THAT EVENTUALLY FORM FROM MAGMATIC SYSTEMS TYPICALLY HOST A LARGE PORTION OF THE RARE EARTH ELEMENT (REE) BUDGET FOR A GIVEN ROCK. FURTHERMORE THE PHOSPHATE ION IS ONE OF THE PRIMARY CONSTITUENTS IN THE MINERAL APATITE A MINERAL THAT HAS BEEN USED TO ESTIMATE MAGMATIC VOLATILE ABUNDANCES AND/ORHYDROTHERMAL FLUID COMPOSITIONS IN A NUMBER OF GEOLOGIC SYSTEMS FROM SEVERAL PLANETARY BODIES. FROM AN ASTROBIOLOGICAL STANDPOINT PHOSPHATE IS RECOGNIZED AS AN ESSENTIAL COMPONENT IN ALL GENETIC MATERIAL (I.E. DNA AND RNA) AND IT PLAYS A KEY ROLE IN CELLULAR METABOLIC PROCESSES (I.E. ADENOSINE TRIPHOSPHATE); THEREFORE ALONG WITH WATER IT IS AN ESSENTIAL COMPONENT FOR LIFE AND MAY PLAY AN IMPORTANT ROLE IN LIFE DETECTION ON OTHER PLANETS. LITTLE IS CURRENTLY KNOWN ABOUT THE ROLE AND DISTRIBUTION OF PHOSPHATE IN THE MARTIAN INTERIOR AND IN MARTIAN IGNEOUS AND HYDROTHERMAL SYSTEMS. THEREFORE A DETAILED STUDY OF PHOSPHATES WITHIN MARTIAN METEORITES COULD PROVIDE A WEALTH OF NEW INFORMATION ABOUT MARS. THIS PROPOSAL PRESENTS 3 PRIMARY SCIENCE TASKS FOR OUR RESEARCH TEAM: 1) ANEXPERIMENTAL STUDY INTO THE IGNEOUS PHASE RELATIONS AND MAJOR AND TRACE ELEMENT EXCHANGE EQUILIBRIUM OF PHOSPHATES IN A MARTIAN BASALT COMPOSITION (RUN PRODUCTS WILL BE ANALYZED BY EPMA SIMS AND BSE-IMAGING). 2) A SINGLE CRYSTAL X-RAY DIFFRACTION STUDY OF THE STRUCTURE OF THE MERRILLITE/WHITLOCKITE IN MARTIAN SHERGOTTITES AND 3) A COMBINED TEXTURAL AND MICRO-BEAM ANALYTICAL SURVEY(EPMA SIMS AND BSE-IMAGING) OF APATITE AND MERRILLITE/WHITLOCKITE FROM MARTIAN METEORITES TO INCLUDE SHERGOTTITES AND THE SINGLE ORTHOPYROXENITE ALH 84001. THE PRIMARY OBJECTIVES LAID OUT IN THIS STUDY ARE IN KEEPING WITH THE GOALS OF THE MARS FUNDAMENTAL RESEARCH PROGRAM. SPECIFICALLY THE PROPOSED INVESTIGATION SATISFIES GOAL 1 OF THE PROGRAM BECAUSE IT WILL HELP TO CONSTRAIN THE HIGHTEMPERATURE PORTION OF THE MARTIAN PHOSPHATE CYCLE WHICH WILL COMPLIMENT PRESENT EFFORTS TO UNDERSTAND THE LOW-TEMPERATURE PORTION OF THE MARTIAN PHOSPHATE CYCLE. MOREOVER THE DATA COLLECTION ON MARTIAN PHOSPHATES SATISFIES GOAL NUMBER 6 OF THE PROGRAM BECAUSE IT REPRESENTS THE COLLECTION OF AN IMPORTANT BASIC GEOCHEMICAL DATASET THAT IS REQUIRED FOR UNDERSTANDING THE MARTIAN PHOSPHATE CYCLE. THE EXPERIMENTS PROPOSED IN SCIENCE TASK 3 SATISFY GOAL 5 OF THE MFR PROGRAM BECAUSE THEY WILL BE THE FIRST EXPERIMENTAL INVESTIGATION INTO PHOSPHATE PHASE RELATIONS OF A MARTIAN COMPOSITION AND THE FIRST EXPERIMENTAL INVESTIGATION INTO MINOR AND MAJOR ELEMENT PARTITIONING BETWEEN CO-EXISTING PHOSPHATES AND MARTIAN BASALTIC MELT WHICH WILL BE OF GREAT IMPORTANCE FOR UNDERSTANDING PHOSPHATES IN IGNEOUS AND HYDROTHERMAL SYSTEMS ON MARS AND IN MARTIAN METEORITES.