IN THIS STUDY WE PROPOSE TO INVESTIGATE THE GENERATION REDISTRIBUTION AND MIXING OF REGOLITH ON THE MOON AND TO MAKE DIRECT COMPARISONS BETWEEN MODEL SIMULATIONS SPACECRAFT OBSERVATIONS LUNAR SAMPLES AND METEORITES TO BETTER UNDERSTAND THE SURFACE PROCESSES AND TIMESCALES INVOLVED ON A WIDE RANGE OF IMPACT-DOMINATED PLANETARY SURFACES. THE BASIC PROBLEM THAT WE WISH TO ADDRESS IS: WHAT IS THE DISTRIBUTION OF MATERIAL IN THE UPPERMOST LAYERS OF LUNAR REGOLITH THAT HAS BEEN ISOTOPICALLY RESET BY INDIVIDUAL IMPACTS? THE PROPOSED WORK WOULD DEVELOP A FULLY THREE-DIMENSIONAL REGOLITH/MEGAREGOLITH EVOLUTION MODEL WHICH LEVERAGES TWO EXISTING WELLTESTED AND PUBLISHED MODELS: (I) CRATERED TERRAIN EVOLUTION MODEL (CTEM) [RICHARDSON 2009] WHICH NOW INCLUDES DEPOSITION OF PROXIMAL AND DISTAL EJECTA [HUANG ET AL. 2017]; AND (II) A TWO-DIMENSIONAL MODEL OF IMPACT-INDUCED HEATING OF THE CRUST AND IMPACTINDUCED AGE-RESETTING [ABRAMOV ET AL. 2013]. THE PROPOSED COMBINED MODEL WOULD TRACK AGES OF IMPACT MELTS IN SEVERAL ISOTOPIC SYSTEMS AND PREDICT IMPACT MELT AGE DISTRIBUTIONS AS A FUNCTION OF DEPTH. THE MODEL OUTPUT WOULD THEN BE STATISTICALLY COMPARED TO MELT AGES IN LUNAR METEORITES WHICH REPRESENT A FAIRLY RANDOM SAMPLING OF THE UPPER REGOLITH. THROUGH THIS COMPARISON AN ASSESSMENT OF SEVERAL PROPOSED SCENARIOS OF EARLY LUNAR BOMBARDMENT HISTORY WILL BE PERFORMED. IN TASK I A LIBRARY OF EJECTA VOLUMES TEMPERATURE DISTRIBUTIONS AND MEAN MELT FRACTIONS FOR EJECTA BLANKETS ASSOCIATED WITH A BROAD RANGE OF IMPACTORS IN THE 1-200 KM RANGE WILL BE CREATED. IN TASK II AN EXISTING ONE-DIMENSIONAL MODEL OF AGE-RESETTING WITHIN COOLING IMPACT EJECTA BLANKETS WOULD BE USED TO CREATE A LIBRARY OF THE DEGREE OF AGE-RESETTING IN THE DEPTH-TEMPERATURE PARAMETER SPACE. IN TASK III THE REGOLITH AGE-RESETTING MODEL WOULD BE RUN FOR SEVERAL BOMBARDMENT SCENARIOS INCLUDING A POST-ACCRETIONARY EXPONENTIAL DECLINE AS WELL AS "SPIKE-" AND "SAWTOOTH-" TYPE LATE BOMBARDMENTS. IN TASK IV THE RESULTS OF THE REGOLITH MODEL WILL BE COMPARED TO RECORDED MELT AGES IN LUNAR METEORITES USING STATISTICAL METHODS. THE PROPOSED RESEARCH IS DIRECTLY RELEVANT TO THE SOLAR SYSTEM WORKINGS (SSW) PROGRAM WHICH SEEKS TO "ADDRESS THE PHYSICAL AND CHEMICAL PROCESSES THAT AFFECT THE SURFACES ... OF PLANETARY BODIES." THEORETICAL INVESTIGATIONS THAT INCLUDE "DATA SYNTHESIS RELEVANT TO THE PHYSICAL AND CHEMICAL PROCESSES AFFECTING PLANETARY SYSTEMS" ARE ENCOURAGED BY SSW AND PROCESSES THAT RESULT IN "EVOLUTION AND MODIFICATION OF SURFACES" SUCH AS IMPACT CRATERING ARE SPECIFICALLY HIGHLIGHTED. THE PROPOSED INVESTIGATION DOES NOT HAVE A SIGNIFICANT DATA ANALYSIS COMPONENT AND IS THUS MORE APPROPRIATE FOR SSW THAN LUNAR DATA ANALYSIS PROGRAM. THIS PROPOSAL DIRECTLY ADDRESSES THE HIGHEST LUNAR SCIENCE PRIORITIES IDENTIFIED BY THE NATIONAL RESEARCH COUNCIL (NRC) AS WELL AS THE GUIDING THEMES AND OBJECTIVES IN THE SOLAR SYSTEM EXPLORATION ROADMAP AND THE NASA STRATEGIC PLAN.