Experiments on Natural-Scale Basaltic Lava Flows: Scope and First Results of the Syracuse University Lava Project

The Syracuse University Lava Project creates natural-scale basaltic lava flows for scientific investigations, educational opportunities and artistic projects. Modified furnaces designed for melting and pouring metals are used to create individual basaltic lava flow lobes of up to 450 kg (10-2m2) with the potential to generate much larger flow fields under controlled conditions. At present, the starting material used in 1.1 Ga Keewenan basalt from the Mid-Continent Rift in NW Wisconsin, a relatively uniform, well-characterized tholeiitic-alkalic basalt. Other compositions (andesite, komatiite, carbonatite) are planned for future experiments. Basaltic gravel is heated to 1100° to 1300°C in a crucible resulting in homogeneous, convecting basaltic magma. Lava is poured over a variety of surfaces including rock slabs, wet or dry sand, H2O or CO2 ice, rough or smooth material, and confined or unconfined channels. Resulting lava flows can be dissected for mapping details of morphological and textural variations. Video from various perspectives is used to document flow behavior and evolution. Infrared images constrain flow temperatures. Textural features of flows such as vesicles and plagioclase microlites have vertical and lateral variations similar to those of natural flows. Differing experimental set-ups provide analogs for a wide range of terrestrial, marine, and extraterrestrial lava flows. In an initial series of experiments, basaltic lava flows (50-200 kg) were poured over dry sand at near constant effusion rates (~10-4m3s-1). Flow temperature and slope were varied to produce a range of different flow morphologies. The results show systematic behavior consistent with observations of natural lava flows and analog experiments. At relatively high T (\u3e1200°C) and steeper slopes (\u3e15°) thin, narrow, leveed flows form. At intermediate T and slope, sheet-like, ropey, pahoehoe forms develop. Flows at the lowest T (1100°C) and gentlest slopes (\u3c10°) investigated resulted in toey, to tube-fed, inflated pahoehoe flows. T and slope show broadly linear correlations with Ψ (ratio of rate of crust formation to heat loss). Future experiments will seek to replicate and more fully document these results and explore the effects of varying effusion rates