9316881 Self We propose that large volume basaltic lavas, such as the CRB lavas, achieved their great flow length by semi-continuous output of magma and thermally efficient emplacement, which allowed lavas to spread as far as topography would permit (in some cases > 500 km). The consensus of research undertaken is that flood basalt lavas of the Columbia River province were erupted as thermally efficient, large-scale pahoehoe sheet flows; any one flow field grew progressively over a considerable time-span (months to years!). We propose continued investigation into emplacement mechanisms of flood basalt lavas with the aim of refining our current ideas on the rate at which they were erupted, and what the possible impact of a flood basalt eruption, or series of eruptions, was on the atmosphere. In particular, this grant will enable Sara Finnemore to complete her PhD work on this project.