A STUDY THAT INTEGRATES THREE ADVANCED ANALYTICAL CAPABILITIES TO INVESTIGATE HOW EARTH’S INTERIOR AND ATMOSPHERE HAVE EVOLVED TOGETHER OVER TIME. MEASUREMENTS OF GEOLOGICAL ARCHIVES OF ANCIENT ATMOSPHERIC AND VOLCANIC GAS WILL ADVANCE THE STATE OF THE ART IN MULTIMODAL ANALYSIS OF ACTINIDES AND NOBLE GAS ISOTOPES IN ENVIRONMENTAL AND GEOLOGICAL SAMPLES. TWO GRADUATE STUDENTS AND AT LEAST ONE UNDERGRADUATE WILL BE TRAINED IN MODES OF ANALYSIS AND DATA INTERPRETATION THAT ARE RELEVANT TO THE PROGRAM GOALS. AN EXISTING AWARD (DENA0003911) FOCUSED ON ESTABLISHING NEW LINKS BETWEEN THE THREE ANALYTICAL MODES (SECONDARY ION MASS SPECTROMETRY, MULTI-COLLECTOR NOBLE GAS MASS SPECTROMETRY, AND X-RAY ABSORPTION SPECTROSCOPY) TO BETTER UNDERSTAND THE EVOLUTION OF EARTH’S ATMOSPHERE OVER THE PAST 3.5 BILLION YEARS. THE PROPOSED WORK WILL LEVERAGE WHAT WE HAVE LEARNED IN THAT FIRST PHASE OF THE EFFORT TO LAUNCH AN EXPANDED STUDY OF HOW THE EARTH’S ATMOSPHERE AND MANTLE HAVE EVOLVED TOGETHER OVER TIME DUE TO PLANETARY PROCESSES THAT ARE UNIQUE WITHIN THE SOLAR SYSTEM.