Distribution of Small Volcanic Constructs on Earth, Mars, Venus and the Moon: Comparisons and Contrasts

Groups of small (<20 km basal diameter) volcanic constructs are observed on Earth, Mars, Venus, and the Moon. By comparing the spatial distribution and edifice morphology of small volcanoes within individual groups on the terrestrial planets, we hope to constrain the magmatic plumbing conditions responsible for their formation.

The type example for a shield field on Earth is the Snake River Plain, a basaltic feature consisting of overlapping low shields, and their associated lava flows and tubes. However, scoria cone fields are more abundant than shield fields on Earth, and their spatial distribution may provide insight into planetary processes as well. Clusters of shield volcanoes are abundant on Mars, and available data allow us to distinguish between scoria cones and shield volcanoes there, indicating that scoria cone fields are rare on Mars. This suggests that, in general, martian magmas may be less gas-rich than terrestrial ones.

Lunar domes and cones tend to have shallower flank slopes than terrestrial shields and cones, possibly due to the low viscosity of lunar lavas. The Gruithuisen domes, Marius hills and Jura hills are all located within Oceanus Procellarum, and the distribution of individual edifices within these clusters will be compared with the distributions observed on Earth and Mars.

Small shields are ubiquitous on Venus: they are the most abundant volcanic edifice on that planet. Quantifying the spatial distribution of individual shields within a given shield cluster for comparison with Earth, Mars, and the Moon, has the potential to reveal important information about magmatic plumbing, lithospheric and crustal properties.