SCIENTIFIC GOALS AND OBJECTIVES: THIS RESEARCH WILL ADDRESS FUNDAMENTAL QUESTIONS OF MARS GEOLOGY (SMD MARS EXPLORATION SCIENCE GOAL 3). SPECIFICALLY WE WILL INVESTIGATE THE MAGMATIC HISTORY AND MANTLE EVOLUTION OF MARS AS REVEALED BY THE METEORITE RECORD FROM A SINGLE MARS METEORITE EJECTION SITE. UNDERSTANDING THE NATURE AND TIMING OF MAGMATIC ACTIVITY ON MARS HAS IMPLICATIONS FOR PERIODICITY OF MAGMATISM TIMING OF VOLCANIC GAS FLUXES INTO THE ATMOSPHERE AND THE NATURE OF MANTLE DYNAMICS OVER MOST OF MARS HISTORY. THE MAJOR SCIENTIFIC QUESTIONS ADDRESSED IN THIS RESEARCH PROPOSAL ARE: 1) WHAT CAN MARTIAN METEORITES THAT ARE LAUNCH-PAIRED TELL US ABOUT PERIODICITY OF VOLCANIC ACTIVITY AND CHANGES IN MANTLE SOURCES FROM A SINGLE MARS EJECTION SITE (I.E. A VOLCANIC STRATIGRAPHY) THAT RECORDS OVER 2 BILLION YEARS OF MAGMATISM? 2) WHAT ARE THE NATURE OF MANTLE AND PERHAPS CRUSTAL COMPONENTS IN THE MAGMAS THAT PRODUCED SOME NAKHLITES? ARE THESE A RESULT OF MANTLE SOURCE HETEROGENEITIES AND/OR ASSIMILATION PROCESSES? 3) WHAT CAN THE CHARACTERIZATION OF NEW MARTIAN METEORITE FINDS TELL US ABOUT THE EVOLUTION OF MARS? THE EARLY AMAZONIAN SPECIMEN NWA 7635 WAS DISCOVERED THROUGH A PETROLOGIC AND GEOCHEMICAL SURVEY OF RECENT FINDS. THE RESEARCH PLAN WILL SPECIFICALLY ADDRESS THESE QUESTIONS BY: 1) INVESTIGATING THE AGE PETROLOGY MAGMA EVOLUTION AND MANTLE SOURCE COMPOSITIONS OF MARTIAN METEORITES THAT ARE LAUNCH-PAIRED FROM A SINGLE EJECTION SITE (E.G. LAPEN ET AL. 2017). 2) EVALUATING THE NATURE OF MANTLE AND PERHAPS CRUSTAL COMPONENTS IN NAKHLITE PRODUCING MAGMAS BY STUDYING THE PETROLOGY AND ISOTOPE GEOCHEMISTRY OF MARTIAN ALTERATION PRODUCTS AND IGNEOUS PHASES. 3) CONDUCTING PETROLOGIC AND ISOTOPIC SURVEYS OF NEWLY DISCOVERED MARTIAN METEORITES IN ORDER TO IDENTIFY SAMPLES WITH ATTRIBUTES THAT ARE DIFFERENT FROM THOSE OF THE PREVIOUSLY STUDIED MARS METEORITE POPULATION (E.G. NWA 7635). METHODS: THE SOURCE LU/HF RB/SR AND SM/ND COMPOSITIONS WILL BE CALCULATED FROM ISOCHRON INITIAL 176HF/177HF 143ND/144ND 87SR/86SR RATIOS. SAMPLES LISTED IN THIS PROPOSAL INCLUDE SHERGOTTITES: NWA 2046 NWA 2626 NWA 4480 NWA 4925 NWA 5789 NWA 6162 AND TISSINT* (*STREWN FIELD STONES). WE WILL ALSO INVESTIGATE THE FOLLOWING NAKHLITES: NWA 10153 NAKHLA YAMATO 000593 NWA 998 AND MIL 03346. RELEVANCE TO NASA SOLAR SYSTEM WORKINGS PROGRAM: THE PROPOSED WORK WILL HELP CONSTRAIN THE ABSOLUTE VOLCANIC CHRONOLOGY OF MARS FURTHER THE UNDERSTANDING OF THE EVOLUTION OF THE MARTIAN MANTLE/LITHOSPHERE AND PROVIDE CONSTRAINTS ON THE INTERACTIONS OF MAGMAS WITH MANTLE MATERIALS AS WELL AS PERHAPS CRUSTAL MATERIALS (I.E. PRIMORDIAL CRUST) AND/OR HYDROTHERMAL FLUIDS. THE SOLAR SYSTEM WORKINGS SOLICITATION SEEKS PROPOSALS THAT USE LABORATORY STUDIES THAT EXAMINE PHYSICAL OR CHEMICAL PROPERTIES AND PROCESSES STUDIES OF SAMPLE OR ANALOG MATERIALS OF OTHER SOLAR SYSTEM BODIES FIELD STUDIES OF TERRESTRIAL ANALOGS OF PLANETARY ENVIRONMENTS OR THEORETICAL AND NUMERICAL MODELING OF PHYSICAL OR CHEMICAL PROCESSES. SPECIFICALLY THE PROGRAM SEEKS PROPOSALS THAT ADDRESS PLANET SURFACES AND INTERIORS INCLUDING: PLANETARY VOLCANISM AND LITHOSPHERIC AND MANTLE EVOLUTION. OUR PROPOSED INVESTIGATION WILL ADDRESS THESE SCIENCE GOALS AND IN A BROADER SENSE OTHER WIDE-RANGING GOALS THAT RELY ON GROUND-TRUTH DATA THAT CAN ONLY BE OBTAINED FROM DIRECT SAMPLE ANALYSIS (I.E. IN SITU MEASUREMENTS OR ANALYSES OF METEORITES).