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The lava flow field southwest of Arsia Mons, Mars has complex volcanic geomorphology. Overlapping flows make observations of their total lengths and identification of their source vents impossible. Application of flow emplacement models, which rely upon physical parameters such as flow length, using only the exposed flow may produce inaccurate estimates of effusion rate, viscosity, and yield strength. We use an established terrestrial thermorheological model (PyFLOWGO), modified to Mars conditions, to estimate effusion rates, viscosities, yield strengths, and possible vent locations for five Mars flows. Our investigation found a range of effusion rates from 2,500 to 6,750 m3 s−1 (average of ∼4,960 m3 s−1). These results are an order of magnitude higher than terrestrial channelized basaltic flows. Corresponding modeled viscosities and yield strengths ranged from 9.4 × 103 to 6.6 × 105 Pa s (average of 5.5 × 104 Pa s) and 66 to 381 Pa (average of 209 Pa), respectively. A novel secondary application of PyFLOWGO that assumes upslope channel narrowing provided estimates of the entire channel length, which is on average four times longer than the exposed portions. Projecting these lengths upslope shows that four of the five flows may have a common vent location, which shares morphologic similarities to other Tharsis region vents. This modeling approach for partially‐exposed lava flows makes it possible to not only determine eruptive parameters, but also to estimate total channel lengths and thereby identify possible source vents. Plain Language Summary: Volcanism is a critical component of Mars' surface formation and evolution. Some of the most recent volcanic activity occurred southwest of Arsia Mons, a volcano in the Tharsis Volcanic Province. A major limitation for studying flows in this region and elsewhere on Mars is that the sources of these flows are not known because their upper/near‐vent parts are commonly buried. We used a novel modeling application for five flows southwest of Arsia Mons to first estimate eruption and flow parameters (e.g., flow rate and viscosity) and then, a possible vent location. We measured flow dimensions (e.g., channel width and length) to corroborate model results. Modeled flow rates are approximately 10 times higher than estimated for large flows on Earth but are within the range of prior modeling results for Mars. Lava flow properties were similar to values for flows on Earth, but lower in comparison to past studies of Mars. We also identified a potential source for four of the five flows. These results show that the observed portion of a lava flow only represents a fraction of the total flow length, and that high flow rates are necessary to produce the long flow lengths on Mars. Key Points: Lava flows in the southwest flow field of Arsia Mons are not fully exposed, which hinders emplacement modeling based solely on the observable flow dimensionsThe total channelized flow length, effusion rate, viscosity, yield strength, and potential vent location for each flow are estimated using the PyFLOWGO modelFour of the flows back‐project upslope to a potential vent location examined in detail using context camera and mars orbiting laser altimeter data [ABSTRACT FROM AUTHOR]

Daedalia Planum contains numerous young lava flows with diverse flow morphology. Previous thermal infrared studies avoided this region because of the moderately high visible albedo, assumed to be caused by optically thick dust, and overall low thermal inertia. The Daedalia Planum flows, however, have some of the roughest surfaces on Mars and display an unusual thermophysical behavior that most likely indicates different areal percentages of dust, sand, and lava outcrops. Recent studies suggest that these surfaces contain significant proportions of lava outcrops rising above low‐lying regions of sand with a spatially discontinuous dust layer. A multi‐instrument, multispectral approach combined with prior morphological mapping is applied here to discriminate between individual flows and determine the variation of thermophysical units on the surface. High‐resolution ConTeXt Camera and High‐Resolution Imaging Science Experiment data are used to investigate the flow surfaces and degree of mantling. Thermal Emission Imaging System and Thermal Emission Spectrometer thermal infrared data are analyzed to quantify the thermophysical variations between flows, identify surfaces with minimally mantled lava outcrops, and apply a thermophysical classification to differentiate the surface units. The results demonstrate that the observed thermal variations are due to different distributions of blocky lavas and sand infill. A majority of lava flows with rough surfaces display a diurnal and thermal inertia response indicative of a larger areal percentage of those outcrops versus that of sand and dust. This approach identifies surfaces with more exposed lava outcrops, promising targets for future composition analysis, in regions previously thought to be too dusty for such studies using thermal infrared data. Plain Language Summary: Daedalia Planum contains some of the youngest and most abundant volcanic activity on Mars. The lava flows exposed here were considered too dusty for previous thermal infrared studies, but our analysis suggests that the dust is not uniform and these surfaces contain significant proportions of lava outcrops rising above low‐lying regions of sand with a discontinuous dust cover. The presence of different areal distributions of dust, sand, and lava outcrops on these flows is further supported by the unusual temperature behavior between flows as well as other studies showing that these flows have the roughest surfaces on Mars. Visible data are used to investigate the flow surface morphology and potential degree of dust cover. Thermal data combined with a thermophysical classification are used to evaluate the temperature response between. These temperature variations are due to different distributions of lava outcrops, sand infill, and dust mantling. Most lava flows with a rough surface display a temperature response suggesting the presence of a larger percentage of lava outcrops versus sand and dust. These surfaces, identified as having minimal dust or more exposed outcrop, represent promising new targets for future compositional analysis. Key Points: Unusual thermophysical variations are present on lava flows in Daedalia Planum that are not easily explained by observed thermal inertiaA multi‐instrument, multispectral approach is used to identify the potential subpixel distribution of lava outcrops, sand, and dustRough surfaces with a low day and high night temperature response contain the greatest percentage of exposed lava outcrops in the flow field [ABSTRACT FROM AUTHOR]

We present a comprehensive global catalog of the geomorphological features with clear or potential relevance to subsurface ice identified during the Dawn spacecraft's primary and first extended missions at Ceres. We define eight broad feature classes and describe analyses supporting their genetic links to subsurface ice. These classes include relaxed craters; central pit craters; large domes; small mounds; lobate landslides and ejecta; pitted materials; depressions and scarps; and fractures, grooves, and channels. Features in all classes are widely distributed on the dwarf planet, consistent with multiple lines of observational evidence that ice is a key component of Ceres' crust. Independent analyses of multiple feature types suggest rheological and compositional layering may be common in the upper ~10 km of the crust. Clustering of features indicates that ice concentration is heterogeneous on nearly all length scales, from ~1 km to hundreds of kilometers. Impacts are likely the key driver of heterogeneity, causing progressive devolatilization of the low latitude and midlatitude crust on billion‐year timescales but also producing localized enhancements in near surface ice content via excavation of deep ice‐rich material and possible facilitation of cryomagmatic and cryovolcanic activity. Impacts and landslides may be the dominant mechanism for ice loss on modern Ceres. Our analysis suggests specific locations where future high‐resolution imaging can be used to probe (1) current volatile loss rates and (2) the history of putative cryomagmatic and cryovolcanic features. The Cerean cryosphere and its unique morphology promise to be a rich subject of ongoing research for years to come. Plain language summary: Planetary scientists are interested in understanding where ice is located in the solar system for two reasons. First, water is necessary to sustain life as we know it, so extraterrestrial ice may provide habitats for past or present life. Second, water ice can be used to produce rocket fuel; in the future, ice may be mined from asteroids, moons, and planets to fuel spacecraft carrying humans. Ceres has been predicted to contain large amounts of ice for decades. When the Dawn spacecraft arrived at Ceres, a major goal for the science team was confirming the presence of ice and understanding how it is distributed beneath the surface. One aspect of that investigation was identifying landforms (features like mountains or craters on the surface) whose appearance indicates the presence of ice. In this study, we compiled a catalog and global maps of all of the "icy" landforms identified during Dawn's primary mission at Ceres. We used these maps, together with detailed analysis of each type of landform, to develop a global picture of how ice is distributed in Ceres' crust. We found that the concentration of ice was spatially variable and that layering of icy and less icy materials may be common. We also identified specific areas of Ceres that may be particularly ice‐rich, so that future missions can target these areas for more analysis. Key Points: We present a global catalog and maps of the morphological features relevant to subsurface ice identified during the Dawn mission at CeresMorphology suggests ice concentration is heterogeneous in the upper kilometers of Ceres' crust; impacts likely contribute to heterogeneityWe highlight locations where future analysis may provide insights into putative cryovolcanic features and current H2O loss mechanisms [ABSTRACT FROM AUTHOR]