Location: Mesa CountySize: 5 acresDesignated: June 1987Land Manager: Bureau of Land Management
The Gunnison Gravels RNA protects unique gravel deposits which prove that the Gunnison river flowed through this site during prehistoric times. Cactus park was part of the ancestral channel of the Gunnison river from 1 to 5 million years ago. The Gunnison River and possibly the Colorado River once flowed through this area and carved Unaweep canyon to the west. Over time tributaries cutting into the soft Mancos shale to the north coupled with the rapid uplift of the harder Precambrian rocks in Unaweep canyon caused the Colorado and Gunnison rivers to flow around the Uncompahgre plateau.
The gently rolling former stream valley floor is cut along the Cactus Park Fault by the eroded channel of an intermittent branch of Gibler Creek. The small residual sandstone bedrock outcrops form low cliffs along he gulch and small ridges and hills in the proposed area. The valley floor is sagebrush and grass covered with isolated stands of piñon-juniper woodland community.