Babylon’s Basaltic Columns
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
These coordinates take you to a basalt flow within the Red Cliffs Desert Reserve near an area known as Babylon Mill to the locals.
It is located on the Babylon Trail and the mill is also known as the Stormont Mill on the Virgin River. The trail name derives from the Mormon naming of Babylon Mill for the silver ore processing plant, an indication of LDS President Brigham Young's discouragement of precious metal extraction because of the ungodly nature of the miners who were attracted into the area.
The area has what we think is an excellent example of Basaltic Columns, these columns are of course throughout this area, But also of interest we think are the pioneer miners use of the columns in the construction of the ore mill on the Virgin river. The builders of Babylon Mill used them to line the spillway where some remain to this day.
Basalt is a common extrusive volcanic rock. It is usually gray to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or gray.
On Earth, most basalt magmas have formed by decompression melting of the mantle. Basalt has also formed on Earth's Moon, Mars, Venus, and even on the asteroid Vesta. Source rocks for the partial melts probably include both peridotite and pyroxenite (e.g., Sobolev et al., 2007). The crustal portions of oceanic tectonic plates are composed predominantly of basalt, produced from upwelling mantle below ocean ridges.
The term basalt is at times applied to shallow intrusive rocks with a composition typical of basalt, but rocks of this composition with a phaneritic (coarse) groundmass are generally referred to as dolerite (also called diabase) or gabbro.
During the cooling of a thick lava flow, contractional joints or fractures form. If a flow cools relatively rapidly, significant contraction forces build up. While a flow can shrink in the vertical dimension without fracturing, it cannot easily accommodate shrinking in the horizontal direction unless cracks form.
The extensive fracture network that develops results in the formation of columns. The topology of the lateral shapes of these columns can broadly be classed as a random cellular network. These structures are often erroneously described as being predominantly hexagonal. In reality, the mean number of sides of all the columns in such a structure is indeed six (by geometrical definition), but polygons with three to twelve or more sides can be observed[5]. Note that the size of the columns depends loosely on the rate of cooling; very rapid cooling may result in very small (Perhaps the most famous basalt flow in the world is the Giant's Causeway on the northern coast of Ireland, in which the vertical joints form polygonal columns and give the impression of having been artificially constructed.
An ancient 13th century religious complex, called Nan Madol, was built on the Pacific island of Pohnpei, using columnar basalt quarried from various locations on the island. The massive ruins remain to this day.
• Notable columnar basalts:
o Giant's Causeway, Northern Ireland
o Borgarvirki Fortress, Iceland
o Devil's Postpile, California
o Devil's Tower, Devils Tower National Monument, Wyoming
o Narooma Basalt, Narooma, New South Wales, Australia
o Samson's ribs, Scotland
o Staffa, Scotland
o Pwisehn Malek, Pohnpei, Federated States of Micronesia [6]
o Basalt Island area, Hong Kong; including High Island Reservoir area, Hong Kong SAR, China
o Reynisdrangar, Vík í Mýrdal, Iceland
o Thunderstruck Rocks (Detunatele), Romania
o Panska Skala, Czech Republic [7]
Geologic information: The St. George area of southern Utah exhibits many classic geologic features of the Colorado Plateau, including flat-lying layers of red sedimentary rock carved into buttes, mesas, and narrow canyons.
However, unlike the rest of the Colorado Plateau, some of the small (less than 1,000 feet high) isolated bluffs in the St. George area are capped by black lava rock, called basalt.
Approximately 1.2 million years ago, lava flowed down a small valley or canyon, that today is the basalt-capped bluff of the St. George Municipal Airport. View looking south.Photo courtesy of the Civil Air Patrol.
Examples include the bluff above Bluff Street (West Black Ridge, the location of the St. George Municipal Airport) and the bluff behind the outlet mall directly east of I-15 at Exit 8 (Black Ridge).
The basalt on top of these bluffs originated as lava that intermittently flowed from small local volcanoes approximately 2.3 million to 20,000 years ago.
Like other liquids, the basalt would flow downhill and into low areas such as stream beds, valleys, and canyons. This presents a puzzle: how does lava flowing downhill end up on hilltops?
1. Former canyon in layered sedimentary rocks.
2. Basalt flows down bottom of canyon.
3. Erosion removes former canyon walls, leaving resistant basalt flow topographically higher.
Unless it defied gravity, the lava should have flowed to low areas, not on bluff tops. And it did; the basalt that caps today's bluffs was originally deposited in canyons and channels.
However, basalt is more resistant to erosion than the surrounding red sandstone and shale. Over time, erosion lowers the surrounding red rock faster than the basalt, leaving the basalt flows high and dry – inverted topography.
How to get there: The bluffs in St. George above Bluff Street and behind the outlet mall are great examples of inverted topography. However, one of the best places to see that the lava originally flowed down streambeds or channels is in a road cut near Hurricane. From I-15 take the Hurricane exit (16) and travel east on State Route 9 for approximately 4 miles. The channel is exposed on the south side of the road before you reach Hurricane.
Inverted Topography in the St. George Area of Washington County
by Mark Milligan
To Log this EarthCache please answer these questions in an Email to Us. Please Include the EarthCache name in your Email.
1. What comprises the underlying stratum (and presumably the surrounding as well) and what type of topography does this formation seem to illustrate ( in the text )
2. What is the orientation of the columns featured here ( Horizontal - Vertical )
3. What forces dictate what shape and size of the columns.
4. Extra credit tell us of other similar features in the area and their rough location.
This cache is located within the boundaries of the Red Cliffs Desert Reserve with the written permission of reserve managers. The Reserve is a 62,000-acre scenic desert area dedicated to the protection of the desert tortoise and other rare or sensitive species of wildlife. Non-motorized recreation is allowed within the lower elevations of the Reserve on designated trails only. If a trail is not marked with official reserve signs, it is not a designated trail. Cache seekers should visit www.redcliffsdesertreserve.com before entering the reserve to be sure that their activity is consistent with rules for responsible recreation that protect this fragile habitat area.
Thank you! Without habitat they have no home.
While you are here check out the old Babylon Mill area further south, there are a few ruins left to see there.
Please stay on designated trails within the Desert Preserve, Please act responsibly.
Additional Hints
(No hints available.)