ONE OF THE GREATEST CHALLENGES IN GEOSCIENCE IS UNDERSTANDING WHEN AND HOW EARTH S ATMOSPHERE BECAME OXYGENATED. THIS GREAT OXIDATION EVENT (GOE) WHICH WAS WELL UNDERWAY BY ABOUT 2.3 BILLION YEARS AGO MADE LIFE LIKE US - AEROBIC LIFE - POSSIBLE. TO ELUCIDATE THE TIMING AND MECHANISM OF THIS CHANGE WE NEED TO QUANTIFY SOURCES AND SINKS OF O2 (HOLLAND 2002; KASTING 2013; CATLING 2013). THE IMPORTANCE OF OXIDATIVE WEATHERING AS AN O2 SINK HAS BEEN ESPECIALLY DIFFICULT TO CONSTRAIN. RECENT MODELS OF THE GOE INVOKE CHANGES IN CONTINENTAL CRUST COMPOSITION AND THUS CHANGES IN THE CAPACITY OF OXIDATIVE WEATHERING TO CONSUME O2 TO EXPLAIN THE TIMING OF ATMOSPHERE OXYGENATION (E.G. LEE ET AL. 2016). HOWEVER THESE MODELS ARE CONTENTIOUS AND POORLY CONSTRAINED BECAUSE THE RATES OF OXIDATIVE WEATHERING AT PRE-GOE LEVELS OF O2 ARE EXTRAPOLATED FROM EXPERIMENTS CONDUCTED AT MUCH HIGHER PO2 (REINHARD ET AL. 2009; REINHARD ET AL. 2013). IMPROVING THESE MODELS REQUIRES HIGH-QUALITY EMPIRICAL DATA CONSTRAINING THE OXIDATION KINETICS OF CRUSTAL MATERIALS (ROCKS SEDIMENTS SOILS) CONDUCTED IN THE PO2 RANGE RELEVANT FOR ARCHEAN WEATHERING. HERE I PROPOSE TO CONDUCT ULTRA-LOW PO2 EXPERIMENTS TO STUDY THE OXIDATION KINETICS OF MAJOR REDUCED SINKS SUCH AS BASALTS KOMATIITES AND ORGANIC-RICH BLACK SHALES AT PRE-GOE PO2. THIS WORK WILL BUILD ON EXPERIMENTS I HAVE ALREADY DONE WITH SULFIDES AND WILL TELL US MORE ABOUT THE ROLE OF THE CONTINENTAL CRUST IN PROMPTING OR DELAYING THE GOE. TO DO THIS I WILL USE RECENTLY DEVELOPED LUMINESCENCE MEASURING OPTODE SENSOR (LUMOS) TO MEASURE CONCENTRATIONS OF DISSOLVED OXYGEN DOWN TO SINGLE DIGIT NANOMOLAR CONCENTRATIONS (LEHNER ET AL. 2014). THESE LEVELS OF OXYGEN ARE UP TO THREE ORDERS OF MAGNITUDE LOWER THAN THE LIMITS OF DETECTION ON PREVIOUSLY DESCRIBED TECHNIQUES AND BEGIN TO APPROACH THE LEVELS OF O2 CONSISTENT WITH AN ARCHEAN ATMOSPHERE (10-5 PRESENT ATMOSPHERIC LEVEL (PAL) 1 NM). USING A CHEMOSTAT DESIGN I WILL CONDUCT OXIDATION EXPERIMENTS WITH LUMOS TO MEASURE KINETIC OXIDATION OF ARCHEAN SHALES KOMATIITES AND GRANITOIDS AS WELL AS BASALTS OF VARIOUS COMPOSITIONS TO BEST APPROXIMATE THE ARCHEAN CONTINENTAL CRUST. THESE OXIDATION RATES WILL TELL US HOW EFFICIENTLY THE ARCHEAN CRUST MAY HAVE CONSUMED O2 PRIOR TO THE GOE AND THUS PROVIDE CONSTRAINTS ON THE ROLE OF OXIDATIVE WEATHERING DURING THE OXYGENATION OF EARTH S ATMOSPHERE. GIVEN NASA S PLANETARY SCIENCE GOALS THE PROPOSED RESEARCH IS WELL-SUITED TO IMPROVE OUR UNDERSTANDING OF THE ORIGIN AND EVOLUTION OF LIFE ON EARTH TO GUIDE OUR SEARCH FOR LIFE ELSEWHERE. IN PARTICULAR IT ADDRESSES THE FOLLOWING PLANETARY RESEARCH PROGRAM INVESTIGATION TOPICS: INVESTIGATIONS INTO THE ORIGINS EVOLUTION AND PROPERTIES OF THE ATMOSPHERES OF PLANETARY BODIES (INCLUDING SATELLITES SMALL BODIES AND EXOPLANETS) AND INVESTIGATIONS INTO THE ORIGIN AND EARLY EVOLUTION OF LIFE THE POTENTIAL OF LIFE TO ADAPT TO DIFFERENT ENVIRONMENTS AND THE IMPLICATIONS FOR LIFE ELSEWHERE. THE WORK ADDRESSES THESE TOPICS BY TELLING US FOUR NEW THINGS: 1) IT WILL HELP US UNDERSTAND THE ROLES OF TECTONICS AND CRUSTAL COMPOSITION IN THE OXYGENATION OF PLANETARY ATMOSPHERES 2) IT WILL INFORM OUR EXPECTATIONS ABOUT HOW COMMON O2 ATMOSPHERES MIGHT BE ON EARTH-LIKE EXOPLANETS 3) IT WILL TEACH US ABOUT THE INTERPLAY BETWEEN BIOLOGICAL AND PLANETARY EVOLUTION IN SHAPING THE COMPOSITION OF PLANETARY ATMOSPHERES AND 4) IT WILL GIVE US CONSTRAINTS ON THE AMBIENT PO2 AND OTHER CONDITIONS THAT WERE MET (IF NOT REQUIRED) BEFORE THE EVOLUTION OF EUKARYOTES AND LIFE LIKE US.