A method of treating a shale-containing subterranean formation penetrated by a wellbore is accomplished by forming a carbon dioxide treatment fluid having a viscosity of less than about 10 mPa-s at a shear rate of about 100 s−1. The carbon dioxide treatment fluid is introduced into the formation through the wellbore at a pressure above the fracture pressure of the formation. In certain embodiments, the treatment fluid may be comprised of from about 90% to 100% by weight carbon dioxide and may contain a proppant. A method of treating hydrocarbon-bearing, shale-containing subterranean formation penetrated by a wellbore may also be carried out by forming a carbon dioxide treatment fluid and introducing the carbon dioxide treatment fluid into the formation through the wellbore at a pressure above the fracture pressure of the formation. The formation being treated may have a permeability of less than 1 mD.