It is called an "impact structure" and not a crater because it is so deeply eroded. Current estimates place the age of the impact between 1.4 and 1.6 billion years. Only the crater's basement rocks remain on the surface in the mountains today. The estimated diameter of the original impact crater is 6 to 13 kilometers (4 to 8 mi).[3] The shatter cones occur for about 1 mile (1.6 km) along the highway, which is interpreted to coincide with a central area within a crater of greater diameter.[4][5]
^French, Bevan M. (1998). Traces of catastrophe. Lunar and Planetary Institute. Retrieved 2008-12-31.
^Fackelman, Siobhan P.; Morrow, Jared R.; Koeberl, Christian; McElvain, Thornton H. (June 2008). "Shatter cone and microscopic shock-alteration evidence for a post-Paleoproterozoic terrestrial impact structure near Santa Fe, New Mexico, USA". Earth and Planetary Science Letters. 270 (3–4): 290–299. Bibcode:2008E&PSL.270..290F. doi:10.1016/j.epsl.2008.03.033.