CRYOVOLCANISM IS THOUGHT TO OCCUR ON MANY OUTER SOLAR SYSTEM BODIES (ESPECIALLY EUROPA ENCELADUS TITAN AND TRITON) RESULTING IN DIAGNOSTIC FEATURES LIKE DOMES FLOWS/SMOOTH PLAINS GEYSERS AND HOTSPOTS. WHILE CRYOMAGMAS ARE THOUGHT TO BE PREDOMINANTLY AQUEOUS OR BRINY CRYSTAL-LIQUID MUSHES THEY SHARE SOME FEATURES IN COMMON WITH SILICATE MAGMAS. THE RHEOLOGICAL BEHAVIOR OF MAGMA (INCLUDING EFFECTIVE VISCOSITY AND YIELD STRENGTH) DEPENDS STRONGLY ON CRYSTAL FRACTION AND CONTROLS MAGMA ASCENT RATE AND STYLE OF ERUPTION / EMPLACEMENT. THE PRESERVED MORPHOLOGY OF VOLCANIC FEATURES IS OFTEN USED TO INFER THE PHYSICAL PROPERTIES OF LAVAS FOR EXAMPLE FLOW THICKNESS AND FLOW-FRONT AND STEEPNESS MAY BE USED TO INFER YIELD STRENGTH. THE SIMPLE BINARY OR TERNARY EUTECTIC NATURE OF LIKELY CRYOMAGMAS MEANS THEIR RHEOLOGY WILL DEPEND PRIMARILY ON CRYSTAL FRACTION ITSELF A FUNCTION OF TEMPERATURE. THE MUCH HIGHER MELTING POINT OF H2O ICE (ICE IH) COMPARED TO NH3 AND CH3OH ICES MEANS THAT WATER ICE IS THE MOST LIKELY CRYSTALLINE PHASE TO BE ENCOUNTERED OVER A WIDE TEMPERATURE RANGE. THE ABILITY OF WATER ICE TO FORM DENDRITES NEEDLES PLATES OR PRISMS DEPENDING ON GROWTH CONDITIONS MEANS THAT TEXTURAL CONTROLS ON RHEOLOGY MUST BE CONSIDERED IN ADDITION TO JUST CRYSTAL FRACTION. THIS PROPOSAL OUTLINES AN EXPERIMENTAL RESEARCH PLAN THAT WILL DETERMINE THE RHEOLOGICAL AND THERMAL PROPERTIES OF LIKELY CRYOMAGMATIC COMPOSITIONS AT CONDITIONS APPROPRIATE TO CRYOVOLCANISM ON OCEAN WORLDS OF THE OUTER SOLAR SYSTEM AND MODEL VARIATIONS IN THESE PROPERTIES AS A FUNCTION OF TEMPERATURE COMPOSITION AND CRYSTAL CONTENT. THE AIM IS TO PROVIDE ROBUST MODELS FOR THESE PROPERTIES TO BE USED IN NUMERICAL MODELS OF ICY/OCEAN WORLD PROCESSES AND TO EXPLORE THE KEY DIFFERENCES BETWEEN THE BEHAVIOR OF CRYOLAVA AND SILICATE MAGMAS DURING COOLING AND CRYSTALLIZATION. WE ANTICIPATE SEVERAL ADVANCES IN OUR UNDERSTANDING OF CRYOLAVA RHEOLOGY: EXPERIMENTAL VISCOSITY DATASET FOR WIDE RANGE OF BRINY- NH3-BEARING AND/OR CH3OH-BEARING AQUEOUS FLUIDS AT TEMPERATURES FROM AMBIENT TO -40 C. VISCOSITY WILL BE DIRECTLY MEASURED IN THE MCR302 AND THE RESULTS USED TO (I) TEST THE TEMPERATURE-DEPENDENCE OF VISCOSITY IN EXISTING MODELS FOR BRINES AND (II) INCORPORATE CH3OH INTO THE MODELS. EXPERIMENTAL RHEOLOGICAL DATASET FOR CRYSTAL-BEARING SLURRIES IN THE NH3-CH3OH-H2O SYSTEM FROM AMBIENT DOWN TO -40 C AT MU AND TO -100 C AT JPL. THE THREE DIFFERENT EXPERIMENTAL APPARATUS HAVE DIFFERENT STRESS-STRAIN RATE LIMITS AND CAN ACCESS A RANGE OF CRYSTAL CONTENTS WHILE VIDEO WILL ENABLE US TO SEE WHAT IS HAPPENING IN THE VISCOMETERS AND INTERPRET TORQUE SPIKES. THE RESULTING DATASET WILL SPAN STRAIN-RATE CONDITIONS FROM THE VENT TO FINAL EMPLACEMENT. EXISTING RHEOLOGICAL MODELS FOR CRYSTAL-LIQUID SUSPENSIONS WILL BE TESTED AND MODIFIED TO INCLUDE STRAIN-RATE DEPENDENCE AS WELL AS CRYSTAL FRACTION. THE RESEARCH PROPOSED HERE ALIGNS DIRECTLY WITH SEVERAL GOALS OF THE SSW PROGRAM (ROSES 2016). THE PRIMARY FIT IS WITH THE THEME OF EVOLUTION AND MODIFICATION OF SURFACES WHICH AIMS TO "CHARACTERIZE AND UNDERSTAND THE CHEMICAL MINERALOGICAL AND PHYSICAL FEATURES OF PLANETARY SURFACES AND FLUID INVENTORIES THAT INTERACT WITH THE SURFACE (INCLUDING CRYOSPHERES). OUR DATA WILL PROVIDE AN EXPERIMENTAL BASIS FOR DEVELOPING THEORETICAL MODELS FOR CRYOLAVA RHEOLOGY DURING COOLING AND CRYSTALLIZATION. THE AIM IS TO UNDERSTAND THE PROCESS OF CRYOVOLCANISM AND TO BE ABLE TO INTERPRET THE PHYSICAL FEATURES IT PRODUCES. RELATED THEMES INCLUDE INTERIOR STRUCTURE AND VOLCANISM. ON LARGER BODIES SUCH AS EUROPA CRYOVOLCANISM SAMPLES THE WATERY OCEANS BENEATH WHOSE COMPOSITION AND IS CONTROLLED BY CHEMICAL PROCESSES OF THE BODY S INTERIOR. UNDERSTANDING THE RHEOLOGY AND FLOW BEHAVIOR OF CRYOLAVAS WILL HELP US ASSESS THE DEGREE TO WHICH THOSE SAMPLES MAY REFLECT OCEAN BULK COMPOSITIONS OR HAVE BEEN SUBJECTED TO FRACTIONATION (E.G. BY CRYSTALLIZATION) DURING ASCENT.