The low viscosity of basalt allows it to flow easily and when extruded in significant enough quantities can create large sheets of what is called a flood basalt. There are many examples of flood basalts around Colorado. Some of the more well known are Grand Mesa, the Flat Tops, White River Uplift, and Raton Mesa.
Below: Indicated with a red arrow are the approximately 23 Ma basalt flows of the Flat Tops.
Colorado Geological Survey