One of Indian Heaven's vents produced a large effusive eruption about 9,000 years ago, forming the Big Lava Bed, which consisted of basaltic lava. With an area of and a volume of , the Big Lava Bed mostly consists of unvegetated basalt. It moved to the south down the Little White Salmon River drainage, which it filled for of its length. Ultimately, the flow extended from its initial source vent, an unnamed cinder cone. It came within of the Columbia River. Another, more ancient lava flow that was especially fluid encompassed the Trout Lake area and extended several miles south, also nearing the Columbia River. Highly voluminous, it also features lava tubes. These lava tubes can be found at many of the lava flows that comprise the Indian Heaven volcanic field, which range from basaltic to andesitic in composition, and extend as far as from their source vents. The eruptive units from the field show normal residual magnetism, suggesting that they were all formed less than 780,000 years ago, with the exception of lava within Gifford Peak's eroded core.