Flood basalt volcanism in the northwestern United States

Abstract

This paper will examine the chemical and isotopic characteristics of the Columbia River Basalt Group in comparison with the basalts of the Oregon Plateau and the Snake River Plain. Similarities and differences between these basalt groups reflect the influence of the pre-eruption tectonic evolution of the area as well as variations in crust and mantle structure and composition beneath the northwestern US. Though relatively unique in their tectonic setting, by erupting through crustal sections of widely varying history and composition, the northwestern US basalts provide many insights into the important factors in the chemical evolution of continental basalts. -Authors