MASS SPECTROMETRY (MS) IMAGING WILL BE USED TO PROBE ARCHAEAN AND PROTEROZOIC SEDIMENTARY ROCKS AS WELL AS PROTEROZOIC MICROBIAL MATS USING FEMTOSECOND-LASER DESORPTION POSTIONIZATION-MS (FS-LDPI-MS) DEVELOPED BY CO-PI LUKE HANLEY. THE FS-LDPI-MS IS A HIGH LATERAL RESOLUTION MS IMAGING METHOD ALLOWING DEPTH PROFILING AND MAPPING OF SINGLE ORGANIC COMPOUNDS. MS IMAGES OF THE DISTRIBUTION OF A GIVEN MASS/CHARGE RATIO (1 -1200 DA) ARE CREATED BY ASSEMBLING MASS SPECTRA COLLECTED FROM INDIVIDUAL FOCUSED LASER SPOTS. THE RESOLUTION OF EACH LASER SPOT CURRENTLY REACHES 2 MICRONS ALLOWING THE RECONSTRUCTION OF MAPS OF ORGANIC COMPOUNDS WITH UNPRECEDENTED RESOLUTION.A MAJOR ISSUE OF ARCHEAN (4 TO 2.5 BILLION YEARS BY) AND PROTEROZOIC (2.5 TO 0.54 BY) RESEARCH IS TO DETERMINE IF LIPIDS EXTRACTED FROM THESE SAMPLES WERE EMPLACED WITHIN THE SEDIMENTS DURING DEPOSITION (SYNGENETIC) OR IF THESE COMPOUNDS ARE POST-DEPOSITIONAL ADDITIONS. ANCIENT SEDIMENTS MAY ALSO BE CONTAMINATED DURING SAMPLING AND PROCESSING. THE SPATIAL DISTRIBUTION OF THE ORGANIC COMPOUNDS IN A SAMPLE OBTAINED BY FS-LDPI-MS IMAGING WOULD BE DIAGNOSTIC FOR THE COMPOUNDS ORIGIN. FOR EXAMPLE ORGANIC COMPOUNDS FOUND EXCLUSIVELY IN A QUARTZ VEIN BUT NOT IN THE SAMPLE GROUNDMASS WOULD NOT BE SYNGENETIC BUT WOULD HAVE BEEN INCLUDED IN THE SAMPLE DURING EMPLACEMENT OF THAT VEIN (POST DEPOSITIONAL HYDROTHERMAL ACTIVITY). THE SPATIAL INFORMATION PROVIDED BY FS-LDPI-MS IN ASSOCIATION WITH CONTEXTUAL MINERALOGY CAN BE USED TO CONSTRAIN THE TIMING OF EMPLACEMENT OF ORGANIC COMPOUNDS WITHIN THE ROCKS AND MORE CONFIDENTLY DETERMINE THEIR BIOSIGNATURE VALUE. ADDITIONALLY WHEN USED ON VERY WELL PRESERVED PROTEROZOIC SAMPLES SUCH AS RARE IMMATURE MICROBIAL MATS FS-LDPI-MS WOULD MAP ORGANIC COMPOUNDS AT THE MICRON RESOLUTION PROVIDING UNIQUE PALEOBIOLOGICAL INFORMATION ON ANCIENT MICROBIAL ASSEMBLAGES. PRELIMINARY RESULTS OBTAINED ON ARCHAEAN METASEDIMENTS FROM THE ABITIBI GREENSTONE BELT (ON CANADA) PROVIDED A POSITIVE FEASIBILITY TEST SHOWING THAT THE DISTRIBUTION OF ORGANIC COMPOUNDS ARE LIMITED TO SPECIFIC ZONES WITHIN THE SAMPLES TENTATIVELY SUGGESTING THEIR EMPLACEMENT DURING AN ARCHEAN HYDROTHERMAL PHASE POST-PEAK METAMORPHISM. THE SAMPLES TO BE ANALYZED RANGE FROM THE NEOPROTEROZOIC TO THE 2.7 BY ARCHAEAN AND ENCOMPASS THE FULL RANGE OF MATURITY IMMATURE SEDIMENTS TO LOWER GREENSHIST METAMORPHICS. ALL SAMPLES TO BE ANALYZED HAVE ALREADY BEEN COLLECTED BY THE PI OR BY COLLABORATOR J. BROCKS (ANU AUSTRALIA).RELEVANCE: THE PROPOSED RESEARCH ADDRESSES THE RESEARCH EMPHASIS "EARLY EVOLUTION OF LIFE AND THE BIOSPHERE" OF THE NASA EXOBIOLOGY PROGRAM ELEMENT BY OFFERING AN UNAMBIGUOUS MOLECULAR RECORD OF LIPID BIOSIGNATURES AND THEIR DISTRIBUTION AT THE MICRON SCALE IN PROTEROZOIC AND ARCHAEAN SEDIMENTARY ROCKS. THE PROPOSED RESEARCH ALSO ADDRESSES THE RESEARCH EMPHASIS "BIOSIGNATURE AND LIFE ELSEWHERE" OF THE NASA EXOBIOLOGY PROGRAM ELEMENT BY DEVELOPING A MOLECULAR MAPPING APPROACH FOR THE ENHANCED DETERMINATION OF THE PRESENCE OR ABSENCE OF VALID BIOSIGNATURES IN ARCHAEAN AND PROTEROZOIC ROCKS. SUCH AN APPROACH IF VALIDATED ON EARTH WOULD TURN INTO AN INVALUABLE HIGH-RESOLUTION IMAGING TOOL UPON MARS SAMPLE RETURN. THE PROPOSED RESEARCH WOULD ADDRESS SOME OF THE KEY RESEARCH QUESTIONS DEFINED IN THE ASTROBIOLOGY STRATEGY 2015 SUBSECTION 5.4 II "WHAT CONTEXTUAL INFORMATION IS REQUIRED TO ENHANCE THE CONFIDENCE IN INTERPRETATION OF BIOSIGNATURES?" BY OBTAINING THE SPATIAL DISTRIBUTION OF MOLECULAR COMPONENTS WITHIN ITS MINERAL CONTEXT AND ALLOWING THE DISTINCTION BETWEEN SYNGENETIC COMPOUNDS POST DEPOSITIONAL ADDITIONS (HYDROTHERMAL) AND COMPOUNDS INTRODUCED DURING SAMPLING AND ANALYSIS. ADDITIONALLY THE PROPOSED RESEARCH IS A DIRECT RESPONSE TO THE NEED FOR ENHANCED TECHNOLOGY TO IMPROVE THE DETECTION OF BIOSIGNATURES AS OUTLINED ON PAGE 118 OF THE ASTROBIOLOGY STRATEGY 2015 DETECTION STRATEGIES FOR EXTINCT LIFE CHEMICAL SIGNATURES.