Cart
The Eocene Green River Formation, forming the slope in the background, contains most oil shale reserves in that state, near Parachute, Colorado, September ©2019 hopkins/neoscenes.

Oil Shale


Much of the CGS website is under heavy re-construction and will be for some time. The Publications area is working normally, but there is a lot of content from our original site that was in desperate need of updating. Please bear with us as we gather new information and rewrite hundreds of pages of material, gather and properly caption high-resolution images and otherwise bring you some very cool new and archival material never before seen! Stay in touch by subscribing to the >RockTalk< blog where we will announce new items periodically.


Colorado has the world’s largest resources of oil shale, by far. Oil shale is actually the rock marlstone which contains kerogen, a precursor to oil. The kerogen must be heated to more than 750 degrees to convert it into oil because it was never buried deeply enough for nature to convert the kerogen to oil.

People have been trying to economically produce oil from this rock for more than a century. Indeed, the CGS issued a report in 1921 entitled, Oil Shales of Colorado. Thus far, technological and economic conditions have not combined to support a sustained oil shale industry in Colorado.