Silica Dome - Overton, NV - Places of Geologic Significance on Waymarking.com

The plaque says, "The sandstone formations that are so prominent in the Valley of Fire are made of sand grains that are almost pure silica. This huge dome is the finest example in the area of such a deposit. The change from white to red in the base of the dome occurs where small quantities of iron in the rock produces a rust-like stain.

Cryptobiotic Soils

Through most of the desert, you will find patches of black crust on the soil. This is a community of algae, riches, mosses, and cyanobacteria that cement the soil topography which allows greater moisture absorption. This crust is only a few millimeters thick and is easy destroyed when walked on. Recovery can take between 7 and 250 years. Please don't walk on it."

aken from the website, "It was spellbinding: a string of red rock, stretched out in a valley, with Lake Mead and even the Grand Canyon beyond. These gnarly, twisted rock formations are a geological playground, a book with the messages of time written by the forces of water, chemistry and wind.


Eons ago, the limestone hills surrounding the Valley were the floor of a mighty ocean. They were lifted and twisted by tectonics and volcanic action, and the ocean receded. During the Jurassic period -- about 150 million years ago -- a vast desert developed. Here, where our mighty rocks now reside, great sand dunes grew. Through time and compaction these dunes became sandstone.


During this process the groundwater flowed through and carried iron oxide and various other minerals. As the water passed through these "petrified dunes," the iron oxide, lime, silica and other minerals painted the stones various hues of red, white, yellow, purple and more. The water also caused fractures in weak areas of the rock, which helped mold the unusual shapes and patterns.

All this happened long ago, and took thousands of years, but the result was spectacular and a startling contrast to the gray hills nearby.

Sandstone is a relatively fragile rock, and as the groundwater continues to flow through the rocks, they are continually changing and eroding. The wind does its part, too, in carving sculptures from old rock. As well, small, new sand dunes form downwind as the rocks erode; with each breeze, the sand forms a new page that records the ongoing drama of desert animal life. Following the tracks of roadrunners, lizards, ring tail cats and much more becomes as fascinating as viewing the red rocks and studying the geological story.

Atlatl RockAs interesting as the geological history is, the human history of the Valley of Fire is just as fascinating. Early Americans recorded their lives at many places in the park. Atlatl ("at-lat-l'') Rock is a pictorial record of migrations, hunts, early tools and weapons, carved in the black patina (desert varnish) of a large sandstone formation by Native American artists as much as 2,000 years ago. The rock is named for the pictograph of an atlatl, a notched stick used to add speed and distance to a thrown spear. It was a predecessor to the bow and arrow. Many more are found along the Petroglyph Canyon Self-Guiding Trail, which is a half-mile, round-trip walk to Mouse's Tank through a sandy canyon. Trail markers are placed to point out interesting features, including numerous prehistoric Indian rock writings.

These prehistoric visitors probably didn't live here; they would come to worship as well as to hunt and harvest. There is evidence that Basket Makers probably first used this valley. Later, an Anasazi settlement grew in the nearby Moapa Valley. There, in what is now known as Overton, a pueblo town grew on the bluff overlooking the valley, and the Anasazi farmed the fertile land near the river.

The Anasazi lived in a pueblo city that grew to be 30 miles long, with a complex society that included trade with the Anasazi cities to the east in the Four Corners area. The Anasazi occupied the area from around 300 BC to about 1150 AD, when they, along with their cousins to the east, vanished. The Moapa Indians, a part of the Paiute Nation, moved to the region later, and were occupying it when the Spanish passed through the region around 1800. About 300 Moapa Indians still live on a reservation north of the Park."

Waymark is confirmed to be publicly accessible: yes Access fee (In local currency): .00 Requires a high clearance vehicle to visit.: no Requires 4x4 vehicle to visit.: no Public Transport available: no Website reference: [Web Link] Parking Coordinates: Not Listed

Visit Instructions:
No specific requirements, just have fun visiting the waymark.

Recent Visits/Logs:

Date Logged Log User Rating   04/01/2016 bluesnote visited it