Searching for NW-SE fractures in the Weak Zone Between Laverkin Quarry and Virgin Fissures near Virgin Town

The FOURTH DIMENSION

Throughout the realms of conjectured Time
There occurs a thought which will not rhyme-
That Beings made with clay-like slime
Don’t fit the current paradigm.

We hunt in vain to find our mate
Who is made from aluminum-silicate;
And not just that, we take the bait
That like the horse- we evol(ate).

The horse we found upon inspection
Not only increased its resurrection;
But with its greater noise subjection
Became a cause-celebre correction.

There was no gradual evolution,
Rather increased air pollution-
Due to human elocution,
With greater Geological Dilution.

Now, feats of punctuated change
Descend upon us like the mange.
With a radioactive rearrange,
The genes, like mind, can soon derange.

When we make a mass defection
Back to Natural Selection,
We will make a gross detection
Of ol’ Nature’s predilection.

Now we view the past through time,
From the rocks, and frames they mime;
How an instant- so sublime-
Is preserved for future rhyme.

Simple time is in Man's head-
Storing there the vital thread,
Bathed in prisms, Gold and Red,
That ne'er wash out till he is dead.

Only He can keep the frames
That will harbor crests and flames,
In our lives- the dreams, the aims-
While whispering in our ear the Fames

Which while soon forgotten stayed,
In our minds' eye forever played-
As Aces in existence staid-
Those Frames of Life which we have made.

Harold L. Overton



The above Slickensides indicate a right-Lateral Fault by the groves and lines of incisions made as a graben dropped near the Hurridane Fault, Hf. We haven't found the confirmation of this feature in other locations of the Hf Scarp, but we did find some interesting rocks and artifacts in the zone of Investigation. These are shown below, and one can see these during hiking near the Laverkin Overlook Trail on top of the Kaibab outcrops just west of the Hurricane Mesa on the south side of Hiway 9.


An outstanding Mystery is the formation of Liesegang Rings, probably due to diffusion and precipitation of dissolved material in water, from a point source. These colored zones in this recently-split rock are not ring-shaped, but were photographed wet and dry to give you another part of the mystery to solve.


Notice the Parallel-ness of the Blue-tinted figure boundaries with the nearby rock surfaces- we'll name this arrangement Leisegang Polygons.


The upper Left-Hand corner shows local fractures, which orient N-S for reference.
Solve this Artifact's age and possible origin, considering that the Structure was on the edge of an incipient Wash, and was not fed by any flume for water storage (the top was above the land surface), and the cementing agent was mud, which would have been quickly eroded by stream flow. The mud cake seemed to be ancient, and the stones were layered limestone from nearby. The structure could have kept out rodents, if a lid could have been made fool-proof. One cannot climb into this artifiact withour ropes, as the sides are well-preserved.
Notice the Cistern-like appearance, which uses mud for sealing.

Try your hand at de-ciphering this young? construction (It is near an underground water pipeline)


North-oriented fractures are not subtle along the Western boundary of the Colorado Plateau.

The Laverkin Quarry has many parallel faults, running almost N-S, while the channel of the Virgin River has NW-SE and NE-SW orientations (making sharp turns, sometimes at abrupt right angles).
For this reason, we will hike from the Hf slickensides, where the fractures and faults definitely orient N-S, to the Virgin River, where the diagonal bends in the river occur. Somewhere in this space, we should find outcrops where the transition occurs. If we are lucky, we will find one fracture displaced by the other to determine the relative ages of the two systems.



Stress Indications from Fracture orientations Verde Valley, AZ has an outcrop of Limestone and other sedimentary rocks which displays many flat and level mesas criss-crossed by fractures. This formation, of Pliocene age, is no more than 5 million years old, so that if there have been earth stress direction change in times less than this age, it would show up in the rock fractures. This does occur, in the Pliocene rocks as well as in older Paleozoic rocks nearby. The Tertiary Verde formation, Tv, occurs in a tear-shaped graben, formed by the Mogollon Rim, Paleozoic Black Hills, and Tertiary basaltic dams to the south. It is cut by the Verde River, which has breached the dams as well as faulted rocks to the north. The whole entity orients almost N-S, and parallels other similar more northerly lake basins in NW Arizona, which altogether give the appearance of parallel diamonds hung on a necklace (separated by intervening uplifts and volcanoes).
In Tv there occasionally occur N-S and NW-SE fractures which intersect, on flat outcrops. This also occurs on Redbeds near Sedona, and there one may evaluate the fracture pattern change. I have observed that the diagonal fractures (NW and NE- their orthogonal companions) occur most often, and I assume that they have been instituted since the late Eocene, or early Oligocene- when the Laramide thrusting terminated, yielding to extension as observed in the dogleg in the Hawaiian-Emperor seamount chain in the Pacific Ocean (41 mybp age). Whenever the two orientations intersect, there is a displacement of one by the other. The fracture displaced (moved out of alignment) indicates the older orientation and this would have been accompanied by a concomitant stress change. The exercise below will be one to determine which is the most recent.
There are both N-S and NW-SE faults mapped by the geologists evaluating the outcrops for quadrangle maps, and this would lead one to expect to find similarly oriented fractures. The first question to answer is:
1. Do fracture displacements yield the same conclusions for both Tv and Paleozoic Redbeds? Secondly, since this answer is “not always”,
2. Does the older Tertiary faulting in Paleozoics occur also in Tv?
There is a significant Miocene fault running N-S through Oak Creek Canyon as well as west of Sedona (in areas with no late Tertiary), so that some N-S faulting preceded the formation of Tv. While there are many NW-SE fractures running parallel to the Mogollon Rim in Paleozoics, they also could have preceded Tv.
The possibility then exists that NW-SE stresses created shear beginning in Eocene and continued into the Miocene, and was superceded by N-S stresses- which would have fractured all rocks of all ages. The NW-SE stresses would have fractured rocks older than Pliocene.
I have seen Redbeds where N-S fractures are displaced by younger northwest ones, but in Tv it occurs the other way around- the N-S are the younger. This is buttressed by the occurrence of a line of anomalous springs, trending N-S from Soda to Winter Springs, through Montezuma Well.
There is one caveat for all this, occurring because of the expressions shown in CA fractures and faulting. The west coast orients NW, and continues on into the Pacific Basin, even after the coastline has re-oriented to the north near Mendocino (where the lateral Transforms turn westward to head out to sea). If one is to infer that the Pacific Plate movement has influenced the Basin & Range, B&R, all the way to the transition zone in AZ and UT, then one has to solve the dilemma of Ca having the youngest N-S Mammoth Lake fault expressions simultaneously with the San Andreas being active on a NW-SE orientation. There is no doubt that both of these orientations are active now- Mammoth Lake has violent thermal expressions running N-S, while the San Andres fault system continues to shear real estate to the NW (a right-lateral faulting system). Is it possible that there are two side-by-side stress systems, both active and both interfering with each other for a significant distance into their interiors?

What about our Hurricane Fault region, where the rocks immediately adjacent to Hf show N-S shear, while further away there are only NW-SE indications? The Laverkin Quarry has many parallel faults, running almost N-S, while the channel of the Virgin River to the south and east has NW-SE and NE-SW orientations (making sharp turns, sometimes at abrupt right angles).
For this reason, we have hiked east from the Hf slickensides, where the fractures and faults definitely orient N-S, to the Virgin River, where the diagonal bends in the river occur. Somewhere in this space, we should find outcrops where the transition occurs. If we are lucky, we will find one fracture displaced by the other to determine the relative ages of the two systems.


Fractures within one kilometer of Hf are monotonously N-S, and can be used for a compass.

The first kilometer of outcrops show no NW-SE fractures, possessing a monotonous array of N-S faults and fractures (hundreds) aligning with the obvious saddle north of Laverkin.
Covering the Paleozoic limestones to the east, the number of parallel fractures orienting N-S was amazingly consistent. A person lost under overcast or with no compass could use the rock fractures to orient his trek.
Occasionally there occurs a set of fractures orienting toward the canyon of the Laverkin Creek (east of the Laverkin saddle), trending 20-30 degrees from north. There was one case where a bend in the limestone fracture could be traced from N-S gradually turning to the NNE. Since there occurred no diagonally-oriented fractures in this border of Hf, the idea that there was a SE weak zone from the slickensides all the way to the Virgin fissures had to be abandoned. Instead it appears that a series of open fractures, tracing N-S and allowing the lands east of Hf scarp to slump readily, is the dominant occurrence. For this case, the interference of the Laverkin splay with the Hf saddle splay has created an extension of the crust to allow erosion and slumping to occur more readily. This can explain why there are many fault expressions in the Laverkin quarry area and why the slumping has created a more gradual slope to the highlands to the east. This allows a road to be developed (hiway 9) climbing the Hf scarp, which is a rare occurrence for the Hurricane Cliffs.
Now we must find why the Virgin River and near by open Fissures to orient to the NW and NE- since this is a definite indication of diagonal fracturing.
Some fractures cross the Virgin River, so could not be related to Spalling alone, but indicate a Previous Weakness (Old E-W Fracture, orthogonal to the N-S sets). Is it possible that the parallel N-S fractures exhibit an overall weakness, similar to that shown in the necklace of pearls arrangement exhibited in the Verde Valley- where a series of grabens or lakes form a NW trend of parallel N-S faults and fractures? If you sheared a block of material N-S,
( ¦
@ ↑ ¦ - arrow is stress direction, @ is right rotation) while bending it, you can create a series of strains which give this configuration.

We searched the flat and almost level CP edge from the Laverkin Overlook Trail to the Virgin River to the SE, looking for any outcrop which was un-moved from the bedrock, and which contained at least two parallel fractures.
The first general observation for this entire area is one of movement of limestone slabs under the postulated influence of ice expansion and soil heaving. The area has been highly weathered, leaving few original outcrops. This is normal for this elevation, where freezing is common- yielding prying of surface flagstones from the bedrock. The flags are rotated and moved around by the large amounts of soil which has been formed from the sandy limestone. This has occurred over the time since the plateau has been eroded down from the original Cretaceous and possible Eocene deposition (erosion after uplift- by several kilometers),
We proceeded with the assumption that the large Fissures near the Virgin River are simply the result of gravitational spalling and shearing after the river has eroded a large almost-vertical canyon. There is now an elevation difference of more than 100 meters in the deepest part, and this would create large shearing and compressive stresses due to gravity. The high bluffs and canyon walls would tend to spall off into the Virgin- parallel to it. Of course for every shearing strain, there is an orthogonal strain occurring because of the three dimensional effect of large chunks of stratigraphic columns acting independently of neighbors. The fractures to seek are the ones which are in neither of these categories- at oblique angles to the Virgin Canyon. Most of interest is the fracture aligning with the Laverkin Canyon to the north and that perpendicular to the Pine Valley Mountains, PVM.
Any fractures of Note will be those occurring in a set of at least two, which are parallel, and which cannot be suspected of having been generated by spalling into the young canyon (remember that there are fissures below the Virgin River- which were the ones taking the water from the dammed portion after diversion of the river for the new pipeline).

Many wide fissures occur a significant distance from the north bank of the Virgin, where some of them are not parallel to the River, but orient toward the Hf saddle to the north and others perpendicular to the PVM (which orients NE-SW)

Notice the Orientation- towards the PVM in the distance (this is to the NW)


A fisher named Fisher fished a fissure
For Brown Trout, a notable delight- a fish, sure!

But the fish, being fissile,
To the depths, went like a missile-
Pulling the fisher quite deep in the fissure.

The fish and his plan, readily outsmarted supercilious Man;
Now other fishers are fishing the fissure for ‘ol Fisher.




This boulder-filled fissure near tne Laverkin-Virgin confluence has more nearby smaller open fractures, which compare with the ones seen on the North side of Virgin River, west of Virgin Town- it is on the east side of a young Monocline and Hogback, west of the Ash Creek near Laverkin Town. The fissure orients N-S, and abruptly makes a left turn toward the west on part of the Monocline.

February 27/08, we trekked NE from the Laverkin Overlook Trail road, to the large open fissures above the north bank of the Virgin River. This is in flat country, with Paleozoic limestones, and which has mostly loose flagstones and soil. Although the loose slabs have mostly N-S fractures, these are discounted, since they are suspected of have been rotated by heaving of soil.
The first observation is that pertaining to limestone which has been left on small hills- these are less suspect of being moved by ice and heaving. There (in the 2nd km east of Hf) fractures are mostly oriented toward the Laverkin Creek and its eastern saddle.


The Fracture displaced is the Older- the Younger maintains its orientation


Notice that there is a trend toward the Laverkin Creek saddle, which is east of the Ash Creek saddle and drainage.


There is also a weak correlation of a Saddle to the SE with the fracture orientation.



Broadly, we did find that there were remnant NW-SE features, such as canyons at a 2 km distance from the Hurricane fault; the NW fractures may have been re-sealed by precipitation of calcite cement closer to Hf.


A Telephoto shot shows the same Canyon- a tributary of the Virgin- and its Diagonal fractures (NW-SE fractures are in the subsurface but difficult to find in the weathered surface Rocks (Due to re-sealing by calcereous cement).
Tentative conclusions are listed below:
1. The order in which fractures, created by regional stresses, occur through time is, older NW (diagonals), 20 degrees from north (Laverkin Creek-associated), and N-S (Hf associated);
2. Drainages in Zion NP were diagonally oriented and have become entrenched, under the NW-SE stress system;
3. Drainages formed in the Pleistocene orient N-S or E-W, the orthogonal set. This includes locally the Coal Pits, the Virgin, and Laverkin Creeks;
4. The first kilometer east of Hf is dominated by N-S fractures, with any NW-SE ones either non-existent or re-sealed by calcareous cement;
5. The second kilometer east of Hf is influenced by the Laverkin Creek system, with stresses oriented somewhat east of N-S; and
6. Finally, the old system initiated in early Cenozoic times- which created diagonal shear- has influenced the Virgin River turn-pattern and other canyons. All of the fractures systems are under the impetus of Extension, where rocks are being pulled apart. This allows rapid erosion and soil-building. Compressional systems, such as the uplift of 21 mybp Pine Valley Mountains, PVM, the 100 mybp Laramide anticlines and folds, and vulcanism are observable and are mostly older than Pliocene (except for Pleistocene volcanoes). The Hurricane fault should have compression associated with it, since there is an uplift of the western edge of the CP within the last kilometer of sediments. Hence, this may be a clue as to the incipience of Hf.

The next Mystery to solve is that noticed for the Hurricane fault in general. Within the first KM east of Hf, the sediments turn updip to the west. This is backward from that expected for an unlifting CP. My explanation is that deep Hot Magma upward movement in the past expanded the sediments (thermally as well as mechanically) close to the fault, attempting to rise. Those on the west side of Hf cannot be seen, since they generally are not exposed. See this feature in the upturned Kaibab or Timpoweep limestone shown in this same photo.


This Photo shows the area near the Hurricane Fault- where Chaos to the West replaces Serenity to the East.

Fractures and Fissures east of Hf by 2 km or more, near The Virgin:
The third foray onto the mesa north of the Virgin River, investigating the fractures which cut the various limestone layers at the ground surface told a different story compared to those nearer Hf. Photos are shown below which illustrate these conclusions. The surface rock may be Kaibab, Pk, or Timpoweap Trmt, but fractures and fissures were independent of stratigraphy- being a stress phenomenon.


A few Diagonal (NW-SE) fractures orient towards PVM,and some are criss-crossed by N-S trends.

1. N-S fractures were not dominant as they were for the first km east of Hf; both sets occurred, and NW-SE sets influenced the path of the Virgin River as well as fissures nearby and far away;
2. Other fractures were more noticeable, but these were not in sets of two or more, and appeared more random;
3. The 20 degrees from north fractures, which previously oriented towards Laverkin Canyon, gave way to N-S features. The distance to both Laverkin and Ash Creek canyons and saddles was sufficient to make the orientation similar for both visual sightings; and,
4. Large entities- such as river paths and large fissures- were influenced more by the diagonal orientations than by the younger Hf N-S fracture pattern. Although a major fissure may trend NW, indicating a major weakness, it may be composed of bends which are at 45 degrees from this orientation- either left or right of the average trend. This hints that the greater weakness, which may be somewhat cemented now, opens up to allow the younger strains (on a smaller scale) to be expressed.


Open Fissures, which are mostly parallel to the present Virgin River course, occasionally orient toward the PVM, and illustrate two perpendicular orientations (but the overall average direction is NW-SE).

COMPARISON OF FISSURES AND THE LAVERKIN MONOCLINE-hOGBACK ANOMALY WITH VIRGIN RIVER FISSURES' ORIENTATIONS.

Laverkin Hogback is oriented N-S, which is not normal for the area (Skewed referenced to other Mesozoic structures), except for Hf- the Hurricane Fault.

Standing on the Hogback, one may see the parallel paths of the Ash and Laverkin Creeks, which represent the sinking path of the monocline to the west.


The Stratigraphy of the Tertiary and Mesozoic is shown on the trail descending from Central Avenue (Laverkin), into the Tortoise Preserve.


Looking E from the Monocline, across the Laverkin and Ash Creeks, one may see all structures pointing down to the north near Hf, until reaching the basalt Plateau to the north. This structure, trending southward toward the same epicenter, will be Photographed from Ash Creek-Toquerville.


This View is toward Zion across the Creeks from Laverkin Monocline, and shows the Large Anomaly at Hf- which is underneath Laverkin Quarry.


Another View of Zion, from Laverkin Monocline (The Big Picture of the Laverkin sink must be taken from the north- Later!).


It is obvious that fissure extension is faster than erosion can fill the Openings.

Ben Everitt and another Hiker stand above a set of Orthogonal Fissures- which indicate the weaknesses presaging them.


The Influence of the N-S Fracture Orientation still manifests itself across the diagonal pattern of the Virgin Canyon.


The 3rd trip along the Virgin River, near Virgin town (west), produced more mainly N-S fissures and fractures, but occasionally there is a major one which is perpendicular to teh PVM


This locaation above the Virgin, north side, shows fractures which are diagonal to each other (45 degrees apart), indicating that both weaknesses may be exploited by the spalling above the Virgin Canyon.


The above comments pertain to Landscape near the proximity to the new (1985) dam on the Virgin, which is used to supply water for the Hurricane Valley.
This work has further disturbed the Crust near the north side and this may be reviewed elsewher in the Blog.

Laramide Geologists

Comments made aside-
From geologists with outdated pride-
Portray those who oft would hide
Behind the dead and ancient Laramide.

'Snow Use: PolyChromatic Geology (2-phase Geothermal Contrasts)

Sullivan's Knoll is a young (10k + years) Cone and Crater (breached), which sits atop or near Ivin's Knoll of 100k+ years basalt flow.

Snow on the Slopes!
A white covering on the ground surface allows an inspection of possible warm spots near WA County’s dormant volcanoes. After watching Mt. Baker (an active vent for the San Juan de Fuca subduction there) to the north of my Snowbird home in Washington State, I realized that there was a method of finding geothermally warm patches of earth independent of using expensive equipment. Every summer, I notice that there is a large area which always darkens before the rest of the mountain. The recent snow in WA County allows a similar test of Sullivan Knoll near my winter residence.

Sullivan’s Knoll is a Crater and Dome which has an age indicated by Erosion of ~ 10k years+. Cracks in driveways oriented towards the present crater and de-gasification is occurring increasingly (possibly due to leveling on the flanks by present developers).

Sullivan's Knoll appears considerably different after a snowstorm- we're searching for a warm spot (I haven't found one)!


The craters and domes in the City of Hurricane are not active, and Utah Geology Survey measurements indicate an age generally in excess of 100k years. However, dating may not be used for young ash and porous ejected rock. In this case, radioactivity used for the measurements from Argon gas is unreliable. Erosion is one method of approximating the ages, and that is the source of the 10k year for the youngest cone. After observing old cones and craters in AZ, HI, NM, and WA, I find that one can estimate the age of last eruption by looking at crater erosion, allowing for the climate of the region.

Hurricane West Crater is older than Sullivan’s Knoll (100k+ compared to 10k+ years), but SK base rests on a previous basalt emission from Ivin’s Knoll which is somewhat older than HWC.

This Crater may be accessed across "Turtle Preserve" lands just north of 600 N, near Gould's Wash.

When a scan is made of basaltic volcano age for the Colorado Plateau, CP, there is a gradual movement of volcanism from the Rio Grande Rift at about 40 mybp, to the St., George area at the 1 mybp date (now, in geological terms).
This basaltic eruption has moved westward around the south edge of the CP in a regular manner. This cannot be due to radioactive heat, since the oldest heat-emitting radioactive compounds have been shoved under the CP on the west edge first (during the Laramide episode). If anything, heat from subducted elements, such as K, Th, and Uranium, would build up on the west side of CP and move eastward with time.
The first possibility that comes to mind for this dilemma is that of density change, where a Physical-Chemical rule for a three factor system has a solution. Whenever the 3 factor system is that of c, composition, T, temperature, and p, pressure (pTc), the rule finds that if a fluid is compressed by depth or pressure, the mass will tend to change density to offset the increased pressure. When this happens, the composition will change to accommodate the system. For example, whenever one pressures an auto tire, the density increases, and the rule states that there will be an attempt to maintain the previous lower density by increasing the temperature. (the tire gets noticeably hot). Oppositely, whenever the air is let out of the tire, the air becomes colder. "Rounding up the Usual Suspects" of Basalt- converting to higher density eclogite- could release Heat, similarly to the compressed AutoTire when it is compressed sufficiently. There are other possibilities, such as Granite converting to Feldsite, but Basalt is the most commom heavy rock which subducts into the Mantle.


A Hogback is developing, as we speak, due to cooling of the Magma near the Hurriane Cliffs (deep below) and its shrinkage more at the face of the Cliffs where the heat can ecape more readily.

For the case of subduction, since the basalt was shoved under the crust earlier on the west side of CP (Laramide episode), the heat from a change of basalt towards eclogite will generate heat lastly, since the depth (p) is less there than on the east side (Rio Grande area). Heat will develop first at the Rift, since the basalt is deeper there. Shallower emplacement near ST. George, UT causes later buildup of heat to the west, since the rate of change of composition is less for the lesser depth (if you pressure the tire slowly, heat will not be as noticeable). The heat of conversion of basalt to eclogite remains, but is slower to develop as a magma.


Notice the Flat and Level Beds East of Hf, compared to Turmoil to the west- this is correlated with the movement of vulcanism clockwise around the CP from the Rio Grande Rift (starting at about 40 mybp until 1 million years ago)


Stout Park Crater, SPC, remains higher in elevation, possibly because it is younger than West Crater, HWC. On the east side of SPC, as well as dominantly on SPC, there is red ash

Views of Scenery near Lake Powell, sent by Karen Hughes

Lake Powell is shrinking rapidly, with our drought conditions- accelerated by Global Warming- Notice the High Bathtub Ring.

Our Striking Colors of Outcropping Rocks are due to the Highly Oxidized Sediments in the Mesozoic, as well as Desert conditions now (in Late Paleozoic time, the massive outpouring of Oxygen from vast new forests displaced the previous dominant CO2 atmosphere- moving CO2 into limestones).

Dry Arroyas offer the best chance to view Ancient Rock Formations, untrammelled by man (But not after Recent Rains)

Call to Hikers

Come take a walk with me today-
We’ll climb a high hill,
Sampling her creation along the way.

We’ll live in our mind’s eye awhile,
Seeing things she did so long ago.
The curt breeze will mask our bootsteps,
While we remember how it was in our childhood-
The collectible stones, the new valleys.
How fresh it all was!

We’ll see the young lavas,
How warm they were yesterday,
When our senses had no imprint of history.
How we laughed at the rocks sliding,
Rushing to cross our paths,
Long before there was such a thing as anxiety.

We’ll cross trickling streams,
If we’re lucky enough for spring rains-
Our hands will slap the cold waters,
Taking the place of bare slender feet.

We’ll love life- once again.

Harold L. Overton

Hurricane Fault Transition Zone has many Clues to Uplift of Colorado Plateau

Part of Hurricane Fault, Hf, can be Measured for Orientation near Hiway 9 east of Laverkin (notice the alignment of a saddle with the fracture direction)


A Monocline or Hogback has risen across the Virgin due to cooling of Subsurface Magma at the face of the Hurriane fault (as evidenced by open cracks on its east side and dropping house lots on the Laverkin cliffs to the East)



Google Photo above shows the Virgin River and its border between Hurricane and Laverkin

Hurricane (Stout) Park Volcano, SPC- S27 41S 13W, named Radio Tower Volcano, by UGS
Access to this hike is made in the Town of Hurricane, going north on 200 West street from Hiway 9, until the city park is reached on the west side (750 West). Turn left, or west, to the gravel road which runs along the boundary of the park, and drive to the end, about 200 yards. Park on the shoulder at the park corner (bounded by a fence corner). Cross a ditch and at the fence corner, enter the volcanic boulder-strewn pasture land. Use either the existing faint trail past the waste storage pond to the west, or hike through open sloping land on the volcanic skirt to the NW. Proceed to the top and walk along an old cattle road to the north rim of the crater. This is just above the Virgin River, where the countryside with all of its’ impressive views are presented. We will look down on the river, the Mesozoic rocks, and the young volcanic detritus toward the north and west.

Section 27 has a 100k+ year extrusion (old lava flow) with a slight crater remaining. Hike with an objective of overlooking the Virgin River at the crater rim, to see the shear cliffs of basalt from several flows and sedimentary rock. A great sweep of the Laramide Virgin anticline, lava flows, and young faulting can be evaluated from a single stance.


Stratigraphy west of Hurricane fault (Hf) is highly contorted, while remaining almost flat and level to the East

Try to focus on the following Features shown, looking to the north and NE:
1. The Hurricane Mesa (high plateau with towers on top) to the east- which has flat and almost level strata (beds of sediments, which are laid parallel to each other);

Hurricane Mesa is to the East (Right of Photo), and is almost flat and level, compared to formations west of it in the Transition Zone
2. Tilted pink-colored monocline or Hogback, just across the Virgin to the north;
3. Basalt flows into the Previous Virgin canyon, as shown by black rock higher in elevation than the present river bottom;


Notice that the Black Basalt has moved into all available crevices

4. Basalt rock which is irregular on the base and sides (indicating filling of old canyons and faults and fissures);
5. Pine Valley Mountains, PVM, to the north and NW- which are an intrusion of granite-like rock rising in the Miocene, about 21 million years ago; and
6. The Virgin Anticline between PVM and the Virgin, which were compressed upward in the Laramide Compression from the west about 100 m.y. ago (notice that it is almost parallel to PVM).



It can be seen that there are at least two flows (there are at least 3 craters in the area) of Quaternary basalts, Qb, which flowed out onto a sedimentary surface, secondly flowed into river canyons, and finally, which were cut by the latest Virgin River erosion (forming the latest canyon- bypassing some of the older ones). In an outcrop on the north side of the Virgin can be seen the Ps or Pleistocene sediments (rubble), underlying a volcanic tuff- both conformable with each other, but not with the underlying Mesozoic and overlying rock. These are now at a 20 degree unconformity with the underlying sedimentary Triassic rock, Trs. These were laid down by the volcano on the south side of the river, occurring also on the north side by that same volcano (dipping in the opposite direction, as seen below Sky Mountain Golf on the south side of the Virgin), and are tentatively dated as Ps, and show that there was no Virgin River then where they now occur, or to the north of the Radio Tower Volcano. There is also an uplift of the Mesozoic to the east, which indicates a Hogback or tilted monocline pointing northward towards the Pine Valley Mountains; this is not a Laramide structure, although the incipience of the anticline several miles to the north might have been.


From below, the basalt which flowed into the Canyon appears more massive

It appears that the 100k years old vulcanism has created compressive stresses (shoving upward), which accentuated the 100m year Laramide structures in the 200m+ years old Mesozoic rocks. There are several faults and fracture indications in the cliff walls and on the surface Jurassic Navajo Jn on the north side of the River. These generally have a NW-SE trend, which is the normal strain pattern for this part of the Western US over the preceding Epoch (Pliocene) and earlier. The N-S patterns, associated with the recent strains and the Hurricane Fault are not as apparent in this location. One mile to the west and further, river bed directions do have this orientation. In this location the river orients either NW-SE or NE-SW, indicating a transition zone for the stress pattern just west of the Hurricane Fault. This is probably due to the rising vulcanism; some young stream patterns on the east side of the crater orient N-S, indicating the age of the new stress system. The author thinks that this stress change has occurred in the last 2-3 m.y, and that this might be offset by local anomalies, such as vulcanism.
It is believed that the Main Hurricane Fault is one mile east of the volcano, as evidenced by vertical beds at the abandoned Laverkin Power plant on the Virgin River, and the fault extends eastward in splays near the Pah Tempe Hot Springs (a 4000 feet separation). The volcano likely is associated with the uplift of the Colorado Plateau, at the Hurricane fault Hf, but the statistics of volcano location depend upon fracture systems more than upon the plane of the fault- and at the ground surface appear random in areal location.

Several Flows found flat ground, a shallow Virgin canyon, and finally a Gorge

Hikes onto Volcanic Craters in Hurricane, UT

Google Map shows the area of interest in the Town of Hurricane, where 3 dormant volcanoes exist.
Red Ash from West Crater was used for Road Metal (Against icing and for shoulders)


Google Space Photo shows the cones within the city limits of Hurricane (notice the Red color from ash broadcasted locally- not a violent blast), UT

Approaching West Hurricane crater from the East, near 600N gravel Road

After a Snowstorm, the View to the South of Radio Tower Crater is Subdued.View from West Hurricane Crater (S27 T41S R13W)
Included are several photos, which were taken from the rim of the W Hurricane Crater. This cone and crater are located about midway between the crater at the Stout Park, SPC, (named Radio Tower Crater by UGS) and that at Sullivan’s Knoll, (SK, above or near Ivins Knoll) - all within 2 km of each other. Although they are not aligned, WHC lies between the two others within the city limits. Both of these other craters are shown in the photos, and you should try to answer the following question as you view them:
Q. Considering the three craters as a set of extrusions from a similar source, what is the relative age of WHC (oldest, youngest or in-between)?
You will see the following clues, as you hike to the summit of the rim:
1. This crater, although better preserved than the one to the east, is the lowest in elevation;
2. The other cones have basalt exposed at their base, while this cone is predominantly red ash and scoria, or lapilli;

West of WHC lies a tongue of Basalt, originating from SK
3. This cone has an erosional path just off its east side, which is lower than the basalt levees exiting from the SPC;
4. This crater rim retains a rough shape of a crater, with erosional breaks, but then it is lower in elevation and has been subject to a smaller gradient for precipitation-causing erosion; and,
5. WHC contains the best deposit of red ash for Road Metal (makes excellent shoulders and coating for icy roads).
Facts and Terms:
The initial basaltic eruptions occurred about 100-200 kilo-years before the present time (kybp) for all three of these craters, although the cones and explosive craters are much younger and are more siliceous-basalt. Surface evidence can only be applied to the final emission for each case, since the rock at the base has been eroded and mostly covered. Basalt came first, evidently from large fractures which had insufficient time to incorporate wall rock containing larger amounts of silica (sand and shale) because of the faster velocity of the magma.
Crater is the interior depression of a cone, much smaller than a caldera (arbitrarily, a crater is less than one kilometer to mile diameter, as contrasted to a caldera, which is larger than a mile).
Extrusions are eruptions which have occurred on the earth’s surface as flows, blasts, solid movements, or gaseous displays.
Intrusions are magma residuals which never reached the earth’s surface, but which may have a similar composition to extrusions which did- e.g. granite (which is a crystallized rock, compared to rhyolite whose crystals are too fine to be seen with the eye), diorite, or gabbro, found at the earth’s surface, after erosion of the cover rock (going from left to right yields the less common outcrops). Granite is equivalent to extrusive rhyolite, diorite to andesite, and intrusive gabbro to basalt in composition.
Lapilli are sand size particles, from 2-64 millimeters (about 1/13 inch to 2.5 inches pebbles), up to cobble size.
Scoria is deposition from the original blast, as from a solid and gaseous suspension in the sky (cinders, clinker, and ash may be other names).
Types of Vulcanism:
a. Cone: a small protrusion from the main volcano or magma source, which is cone-shaped before erosion, e.g. Sullivan’s Knoll or Veyo;
b. Shield, or volcano with a slight slope (resembling a warrior’s shield), such as Mauna Loy in Hawaii- this is predominately composed of basalt; and,
c. Strata or composite: A large cone with large slope and indications of multi- eruptions- alternately flows, blasts, and puddling of lavas (doming), e.g. Fuji.
d. Vulcanism around the Pacific Rim is mainly Andesitic (from the Andes Mountains name), and is explosive- high silica content- while volcanoes from the interior of continents and isolated islands are mainly basaltic and slow-flowing (high iron content from the Mantle). The reason for the explosive vulcanism around the Rim is due to the higher silica content as the various plates dive into the Crust and absorb continental sedimentary rocks (with their large amounts of sandstones and shales). This feature along with the larger fraction of water in the crust yields explosive magma before the subduction reaches the Mantle and its mainly basaltic composition.
e. When basalt is encountered, it indicates mantle or deep Crustal flow, whereas explosive vulcanism denotes recycling of Crustal sediments or Metasediments.


2nd Hike around the rim of the WH Crater

A complete circuit was made around the rim of the West Crater, WHC, to determine the age relative to the other cones occurring within the Hurricane city limits. The rim is eroded in only one location- the southern edge, where erosion has opened a drainage way. Next to this drainage there is a 4th dome, which is obviously younger than WHC (no red ash cobbles overly it), and it is composed of rock which has flowed rather than blasted- (it has a light color, and is layered). This rock is younger than WHC, since it has been eroded less than the red ash cone, and there is a dike of similar material which is on the edge- protruding from the red ash. The dome has no crater (or if so highly eroded), and it is higher than SWHC in elevation; it appears to have flowed laterally and vertically, without volatility.
This dome is closer in distance to SK, relatively aligned with it and SPC, in an arc.
It appears that the dome has risen after the basalt flows of SK and SPC (having a more silicic basalt than either of them). Its lack of excessive erosion indicates that the following eruptions occurred (older time first- see the Google map of the Hurricane- Virgin area, above):
1. Basalt flowed near WHC location, and then proceeded to flow further west, finally damming the Virgin River near hiway 9 bridge (at least 3 flows).

2. Blasts occurred first at SPC?, then at WHC (these first two eruptions may be reversed in time), and lastly at SK;
3. A dome of more siliceous basalt rose, before SK cone was formed, with dikes, west of WHC; and

4. Erosion affected SK the most, followed by SPC, and finally WHC, because of the lesser erosional gradient (elevation) there.

5. There is no red ash covering the Stout Park outcrops, hence West Crater may be the oldest of the 3 volcanoes. (note: UGS has measured the ages of all outcropping volcanic rock in WA County, and finds that Ivins Knoll beneath or nearby Sullivan Knoll is 1 mybp age (volcano Mt. adjacent is 258 kybp), Cinder Pits or West HV is 240 ky, and Radio Tower or Stout Park volcano is 140 ky. This indicates that the vulcanism proceeded northeasterly from Ivin's Knoll and then reversed to form Sullilvan's Knoll last- all within 200kybp.


PVM to the NW shows how this 21 mybp Intrusion has "Jacked up" the whole Region and now has been UNEARTHED by erosion (Previously, before vulcanism, there was at least 10,000 feet of sedimentary Rock above Sea Level).



West of WHC lies a tongue of Basalt, originating from SK (notice the trace of a Fault trending N-S, which allowed basalt to enter a fissure, and which is traced through Jn


A Fourth Dome occurs on the rim of WHC- probably younger than it

Volcanic Oddities on the New Islands of Hawaii

Emergent Steam creates Holes in the cooling Lava, as the groundwater below the new flow is overheated.

Hawaii Volcanic Oddities
The large island of Hawaii is one where a visitor can trace the history of lava flows and their effects on the Land Surface. There has been a historical and present documentation of flowing Lava, as it moved downhill from both Mauna Loa (long mountain) and Kilauea (spewing or spraying, in local lingo) Caldera. Houses have been photoed as they burned from advancing flows, and vegetation has been observed to be encapsulated. The flows are very deliberate, moving at speeds where people can escape them (but not so, for dwellings). Citizens have thrown up barriers, via bulldozers, usually to no avail. But when successfully diverting flows away from houses, they were later sued by neighbors for moving flows onto other properties. Now it is agreed that Pele- the goddess of fire- will get her way, and people must absorb her actions. Covered or burned houses and highways must simply be by-passed for new construction.
Pahoehoe Flows The ropey lava is the easiest for man to adjust to, since the surface is smooth and has low compressive and shear strength. It may be walked on and broken with a pick or hand tool. Vegetation finds the fractures which form upon cooling and begin to grow tall in them within ten years.

Ropey Lava or Pahoehoe

Slow-flowing Lava, such as Pahoehoe, is easy to tread and for fast-growing vegetation to weather (into the numerous shear cracks).

Flora-dated Basalt (instead of Petrified Wood)

Notice the “Tree Rings” made of successive lava insertions in holes left by burning layers of wood. Evidently Lava encapsulated trees before burning, which slowly burned the next layer before filling and burning another layer for subsequent filling.



Small subsidiary Craters

Minor Craters and Domes are due to subsurface flows from the Main Reservoir under Hawaii. This Reservoir may be many miles in diameter, originating from the primary vertical conduit under Mauna Loa- which is much smaller in diameter.

Lava travels long distances through Tubes, emerging unannounced
Notice the side-by-side Crater and Dome, named Mauna Ulu, which are distant from the main Kilauea Caldera. The Reservoir feeding these emissions is wide laterally, but spreads laterally from the main Throat which is only on the order of a mile in diameter (as evidenced by analysis of mineral composition).