The Ojo Alamo Formation is divided into two subunits separated by a large unconformity—a gap in the geologic record.

The lower Naashoibito member (sometimes considered part of the Kirtland Formation) was deposited during the Maastrichtian age of the Cretaceous period, specifically between about 69-68 million years ago.

It overlies the De-na-zin member of the Kirtland formation, though the two are separated by another large unconformity that spans a period of geologic time equivalent to 73-69 million years ago.

[3] The upper unit of the Ojo Alamo Formation is the Kimbeto Member, which was deposited mainly during the earliest Cenozoic (Danian age of the Paleogene period), between 66 and 64 million years ago.

[4] Some researchers have claimed to find isolated non-avian dinosaur remains in the younger Kimbeto Member.

Indeterminate The formation was named by Barnum Brown in 1910 for exposures near Ojo Alamo springs in the San Juan Basin.