OBJECTIVES: THIS PROPOSAL SEEKS TO ANALYZE AND INTERPRET SEDIMENTARY AND HYDRATED DEPOSITS IN AND AROUND LADON BASIN WITH IMPLICATIONS FOR THE AQUEOUS HISTORY OF MARGARITIFER TERRA. LADON BASIN AND SURROUNDINGS HAVE SOME OF THE BEST-DEVELOPED PRESERVED AND EXPOSED FLUVIAL LANDFORMS AND BASIN STRATIGRAPHY ON MARS MAKING IT AN IDEAL SITE TO TEST LOCAL AND REGIONAL SOURCE-TO-SINK PATHWAYS OF SEDIMENTARY ROCKS DEPOSITED BY VARYING PROCESSES UNDER CHANGING ENVIRONMENTAL CONDITIONS DATING FROM THE NOACHIAN THROUGH THE EARLY AMAZONIAN. THE STUDY AREA INCLUDES LADON BASIN NORTHERN LADON VALLES AND SURROUNDING UPLANDS. WHERE CRISM DATA IS AVAILABLE THESE DEPOSITS ARE CHARACTERIZED BY CLAY SIGNATURES THAT COULD REPRESENT FLUVIAL OR LACUSTRINE SEDIMENTS OR HYDROTHERMAL ALTERATION BY VOLCANIC OR IMPACT PROCESSES. THE PROPOSED TASKS WOULD MAKE USE OF MULTIPLE COMPLEMENTARY DATASETS AND ANALYSES (MORPHOLOGIC MINERALOGIC AND STRATIGRAPHIC) TO BETTER ESTABLISH THE AQUEOUS HISTORY OF THIS IMPORTANT REGION OF MARS AS IT RELATES TO PAST CLIMATE AND HABITABILITY. THIS STUDY IS ESPECIALLY TIME CRITICAL BECAUSE TWO TOP PRIORITY MARS 2020 LANDING SITES UNDERGOING EVALUATION AT NEARBY EBERSWALDE AND HOLDEN CRATERS HAVE LIKELY BEEN AFFECTED BY THE SAME AQUEOUS PROCESSES THAT WE INTEND TO INVESTIGATE AS PART OF THIS PROPOSAL. METHODS: WE HAVE ALREADY IDENTIFIED DEPOSITS THAT ARE SEDIMENTARY (I.E. DEPOSITS THAT APPEAR LIGHT-TONED SOMETIMES LAYERED AND ASSOCIATED WITH VALLEYS AND/OR BASINS) AND/OR HYDRATED (AS DETERMINED BY HYPERSPECTRAL DATA) AND SUFFICIENTLY COVERED BY HIGH RESOLUTION DATA SETS TO ENABLE DETAILED ANALYSES. IN TASK 1 WE WILL UTILIZE HIRISE AND CTX IMAGES TO EVALUATE THE MORPHOLOGY CRISM DATA TO INTERPRET THE MINERALOGY AND THESE THREE DATA SETS COMBINED WITH DIGITAL TERRAIN MODELS (DTMS) TO DETERMINE THE STRATIGRAPHY OF SEDIMENTARY AND HYDRATED DEPOSITS. TASK 2 WILL SYNTHESIZE THE RESULTS OF OUR ANALYSES TO EVALUATE THE ENVIRONMENTAL CONDITIONS DURING EMPLACEMENT OF THE DEPOSITS INCLUDING IMPLICATIONS FOR REGIONAL VERSUS LOCALIZED AQUEOUS ACTIVITY THAT CAN BE ASCERTAINED FROM THEIR DISTRIBUTION LITHOLOGIES AND INFERRED ORIGINS. WE INTEND TO COMBINE OUR NEW OBSERVATIONS OF WHAT MAY BE PAST HABITABLE ENVIRONMENTS WITH RESULTS FROM PREVIOUS COMPLEMENTARY STUDIES ELSEWHERE TO PLACE THE ORIGIN OF THE DEPOSITS IN A BROADER GEOLOGIC FRAMEWORK THEREBY HELPING TO DECIPHER THE HISTORY OF POTENTIALLY HABITABLE ENVIRONMENTS IN THE REGION RELATIVE TO OTHER GEOLOGIC EVENTS. RELEVANCE: THIS WORK ADDRESSES THE MDAP GOAL TO ENHANCE THE SCIENTIFIC RETURN FROM MISSIONS TO MARS CONDUCTED BY NASA AND OTHER SPACE AGENCIES BECAUSE IT USES MULTIPLE MARTIAN DATA SETS FROM FOUR SEPARATE ORBITAL MISSIONS (MGS ODY MEX AND MRO) AND WILL CONTRIBUTE TO ONGOING GEOLOGIC ANALYSES OF THE SURFACE OF MARS WITH A FOCUS ON SEDIMENTARY AND HYDRATED DEPOSITS. THE PROPOSED RESEARCH ADDRESSES QUESTIONS ABOUT SEDIMENTARY DEPOSITION AND AQUEOUS ALTERATION THAT WILL GREATLY FURTHER OUR UNDERSTANDING OF SOURCE-TO-SINK PATHWAYS AND FORMATION OF CLAYS IN POTENTIALLY PAST HABITABLE CONDITIONS ON MARS. ADDITIONALLY OUR STUDY REGION ENCOMPASSES THE SAME GEOLOGY OF TWO NEARBY CANDIDATE FUTURE MARS LANDING SITE FOR THE MARS 2020 ROVER (EBERSWALDE AND HOLDEN CRATERS) MAKING PORTIONS OF THIS INVESTIGATION RELEVANT TO THE MDAP GOAL CHARACTERIZATION OF POTENTIAL LANDING SITES FOR FUTURE MARS EXPLORATION MISSIONS. SIGNIFICANT ADVANCEMENTS TO THE FIELD OF MARS SCIENCE INCLUDE: 1) A DETAILED CHARACTERIZATION OF SEVERAL TYPES OF CLAY DEPOSITS FORMED UNDER DIFFERENT ENVIRONMENTAL CONDITIONS; 2) THE EXTENT AND DURATION OF WATER ACTIVITY IN THIS REGION WITH IMPLICATIONS FOR THE GEOLOGIC HISTORY OF EBERSWALDE AND HOLDEN CRATERS THAT IS PERTINENT TO THEIR SELECTION AS POSSIBLE LANDING SITES FOR MARS 2020; AND 3) A BETTER UNDERSTANDING OF SOURCE-TO-SINK SEDIMENT PATHWAYS ON MARS.