See more from this Division: Topical Sessions
See more from this Session: The Geology of Small Volcanic Vents and Their Associated Vent Fields throughout the Solar System
Abstract:
Steepening of slopes occurs in the summit of some plains small shield volcanoes. Absence of angular blocks, thin layering, and irregular collapse of outcrops around the summit crater imply relatively variable (non-massive) lithology, either small narrow flows or small-scale variations in pyroclastic accumulation. Summit edifice development is evidence for secular changes in eruption rates, corresponding lava flow dimensions, and/or relative volatile/magma ratios. Similar late stage trends are observed in some terrestrial fissure eruptions in which diminishing eruption rates are out-paced by de-volatilization of the magmas and late stages of eruption become more fragmental.
Elsewhere in older plains, cratered cones in linear arrays and in more random concentrations remain difficult to assign likely origins. Some are consistent with volcanic origins. Others are probable residual landscape features, while cratered domes of the northern lowlands have been interpreted as possible mud volcanoes.
See more from this Division: Topical Sessions
See more from this Session: The Geology of Small Volcanic Vents and Their Associated Vent Fields throughout the Solar System