Stone rings created by removal of mudboil vegetative rims by fire
Photo from about 100m altitude of stone rings exposed by tundra fire in 1973. After three years, ash has washed away revealing the rings of stones. The boulders, which average 30-50cm in diameter, are heaved to the surface by frost processes, then transported to the mudboils rim as mud is injected to the surface in the middle of the mudboil (see diagram, image 0098, and images of mudboil diapirs, 0050, 0059). Images 0057, 0058 show what this surface looked like in 1973, just after burning, and 0099 shows typical mudboil surface before alteration by tundra fire. See detailed discussion for image 0240.
Updated 05/07/2010 AW