Most of the volcanoes that comprise the Indian Heaven field are monogenetic, only erupting once before becoming extinct. The rest are polygenetic shield volcanoes. About 80 percent of the lava erupted by Indian Heaven volcanoes consists of basalt; it represents the most voluminous Quaternary basalt produced by a volcanic field in the Cascade Arc north of Newberry Volcano in Oregon, with an eruptive output volume between . Basalt composition varies from low-potassium high-alumina olivine tholeiite to calc-alkaline, shoshonite, and alkaline intraplate compositions, though olivine-bearing basalt with different amounts of porphyritic plagioclase dominates. Volcanoes within the field have produced smaller amounts of basaltic andesite and andesite with silicon dioxide compositions up to 59 percent, though dacite is not very common among Indian Heaven eruptive products. Unlike Mount St. Helens, the Indian Heaven field has generated large volumes of basalt but has not caused extensive crustal melting. Most of the lava flows produced by the field have been pāhoehoe, featuring smaller percentages of block flows and ʻaʻā flows. They vary in thickness from , reaching volumes up to ; there are about 40 distinct lava flow groups in the field, totaling in area.