The Mesozoic Era was significant in the formation of what we now call the
Valley of Fire, the Great Basin
north central region of the American Southwest in several ways. The geological
commonality of an area is based upon the similarity of the environment or the
events in that area at specific times in the past.
The Navajo Sandstone formation is believed to be the remains of a huge 150,000
square mile desert which existed in this region from about 192 to 178 million years
ago during the late Lias and early Dogger Epochs.
The Navajo Sandstone is found throughout the Southwest in national and state
parks such as
Zion, Canyonlands, Arches,
Red Rock Canyon, Redstone in Lake
and the Valley of Fire.
At the time of this great desert, the region itself is believed to have been
about 8 to 17 degrees north of the equator. This was a great desert. (1) There are
also remains of permineralized conifer species - petrified wood,
horsetail, fern fragments and other fossilized flora found associated with this
There is some debate as to how plant and animal fossils found their way or may
have originated in this environment. Some suggest that ephemeral lakes were
created from monsoon type storms and that such a process may have contributed
to a spring and playa system, thus support local flora and fauna.
It may also
be possible that the region was part of a huge floodplain from time to time as
mountains in distant areas rose slowly from the sea.
(1) Riggs, N.R. and Blakey, R.C. 1993. Early and middle Jurassic
paleogeography and volcanology of Arizona and adjacent areas. In Mesozoic
paleogeography of the western United States II, Pacific Section, Dunne, G.C. and
McDougall, K.A., eds, 347-76. Los Angeles: Society of Economic
Paleontologists and Mineralogists.