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We have examined thermal emission from 240 active or recently-active volcanic features on Io and quantified the magnitude and distribution of their volcanic heat flow during the Galileo epoch. We use spacecraft data and a geological map of Io to derive an estimate of the maximum possible contribution from small dark areas not detected as thermally active but which nevertheless appear to be sites of...
Observations of Enceladus have revealed active jets of material erupting from cracks on its south polar surface. It has previously been proposed that diurnal tidal stress, driven by Enceladus’ orbital eccentricity, may actively produce surface movement along these cracks daily and thus may regulate when eruptions occur. Our analysis of the stress on jet source regions identified in Cassini ISS images...
The great variety of morphologies observed in the Daedalia Planum lava flows (Mars) encouraged a detailed study of their spectral characteristics, in order to obtain information about lava composition and detect possible differences in the spectra of the flows. The OMEGA spectral data collected from the lava field appear rather similar, with absorptions between 0.8 and 1.4μm and 1.8 and 2.5μm, suggesting...
Using the NIMS Io Thermal Emission Database (NITED), a collection of over 1000 measurements of radiant flux from Io’s volcanoes (Davies, A.G. et al. [2012]. Geophys. Res. Lett. 39, L01201. doi:10.1029/2011GL049999), we have examined the variability of thermal emission from three of Io’s volcanoes: Pele, Janus Patera and Kanehekili Fluctus. At Pele, the 5-μm thermal emission as derived from 28 night...
The Tyrrhena Patera highland volcano, Mars, is associated with a relatively well localized gravity anomaly and we have carried out a localized admittance analysis in the region to constrain the density of the volcanic load, the load thickness, and the elastic thickness at the time of load emplacement. The employed admittance model considers loading of an initially spherical surface, and surface as...
A database of bedrock exposed in crater central uplifts has been compiled from multiple orbital datasets. In this study we focus on uplifts which show decameter-scale layers within the exposed megablocks derived from the bedrock of the preexisting target. This distinctive morphology, found in 41 craters globally, occurs mostly in regions mapped as Hesperian plains material, generally interpreted as...
Spectral analysis of Mare Serenitatis has been carried out using Chandrayaan-1 Moon Mineralogy Mapper (M 3 ) data in order to map the compositional diversity of the basaltic units that exist in the basin. Mare Serenitatis is characterized by multiple basaltic flows of different ages indicating a prolonged volcanism subsequent to the basin formation event. Reflectance spectra of fresh craters...
A planetary global circulation model developed by the Laboratoire de Météorologie Dynamique (LMD) was used to simulate explosive eruptions of ancient martian volcanoes into paleo-atmospheres with higher atmospheric pressures than that of present-day Mars. Atmospheric pressures in the model were varied between 50mbar and 2bars. In this way it was possible to investigate the sensitivity of the volcanic...
It is generally agreed that a dense CO 2 -dominant atmosphere was necessary in order to keep early Mars warm and wet. However, current models have not been able to produce surface temperature higher than the freezing point of water. Most sulfate minerals discovered on Mars are dated no earlier than the Hesperian, despite likely much stronger volcanic activities and more substantial release...
Mars volcanic SO 2 and H 2 S gas emissions are likely the dominant source of martian sulfate, and the source of sulfuric acid. Until this work, the FREZCHEM model lacked SO 2 and H 2 S gases and associated sulfite and sulfide minerals. The specific objectives of this paper were to add these components and associated sulfite and sulfide minerals and phases into FREZCHEM,...
Giant radiating dike swarms on Venus are geomorphic manifestations of deep-seated volcano-tectonic processes. Through an initial series of experiments we assess if these features can be explained as a product of the relationship between magmatism and the flexural stress state caused by lithospheric uplift (due to a rising mantle diapir, plume or underplating processes) using gravitationally loaded,...
On Earth, igneous rocks are generally affected by magmatic differentiation and the volume of intrusive bodies is considered to be 5–10 times larger than the volume of volcanic rocks. In contrast, in the case of Mars, the occurrence of olivine-phyric basalts at Gusev crater (McSween, H.Y. [2006]. J. Geophys. Res. (Planets) 111(E10), E02S10), the primitive nature of at least four picritic shergottites...
Cassini spacecraft images of Io obtained during its flyby of Jupiter in late 2000 and early 2001 were used to determine the lava composition and eruption style of three faint hot spots, Pillan, Wayland Patera, and Loki Patera. We found a maximum color temperature of 1130±289K for Pillan and maximum color temperatures of 1297±289K and 1387±287K for Wayland Patera and Loki Patera, respectively. These...
In 1997, the Pillan volcano on Io was home to a fierce volcanic eruption that emplaced extensive lava flows and a circular plume deposit. The gas/magma flow issuing from the unresolved vent region appeared to form an almost vertical jet. We consider steady eruptions of gas and magma, and take the vent to be either a fissure or a point source. In the fissure scenario, the upper-conduit flow must reach...
New 19μm spectroscopy of Io’s SO 2 atmosphere in 2012 and 2013, when combined with our earlier observations starting in 2001, provides a near-yearly record of atmospheric density in the lowest scale height, spanning almost an entire jovian year. We find that the anti-Jupiter hemisphere atmospheric density is decreasing following Jupiter’s 2011 perihelion passage, confirming our model (Tsang,...
Rootless cones on Mars are a valuable indicator of past interactions between lava and water. However, the details of the lava–water interactions are not fully understood, limiting the ability to use these features to infer new information about past water on Mars. We have developed a model for the pressurization of a dry layer of porous regolith by melting and boiling ground ice in the shallow subsurface...
We present results of crater size–frequency distribution (SFD) analysis of the lower NW flank of the Hecates Tholus volcano, Elysium volcanic province of Mars, by the use of images acquired by the Context (CTX) instrument on board of Mars Reconnaissance Orbiter (6m/pixel in resolution). Previous similar works were focused on the caldera complex of the volcano and some sectors of the lower NW flank...
The Aristarchus region of Oceanus Procellarum is an area concentrated with lunar basalts, which were mainly produced by the last major phase of lunar volcanism on the western nearside. A group of lunar sample and remote sensing scientists have carried out the extensive task of characterization of lunar mare soils with regard to their mineralogical and chemical makeup and regional geologic mapping...
Flat-floored craters have long been recognized on Mars with early work hypothesizing a sedimentary origin. More recently, high-resolution thermal inertia measurements show that these craters contain some of the rockiest materials on the planet, inconsistent with poorly consolidated sedimentary materials. In this study, the distribution, physical properties (morphology and thermal inertia), and composition...
Volatiles play a critical role in determining the nature of volcanic activity on Earth, but their role in the volcanism on Io is less clear. To help determine that role we analyze Voyager and Galileo images of Loki Patera. Loki is the largest caldera in the Solar System and Io’s most powerful volcano, however its eruptive behavior is still not understood. It appears to be relatively volatile poor,...
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