WOODEN WATER PIPE

While exploring the prairie south of Winslow, Arizona I came across a house that had burned down long ago.  The foundation and some partial walls remained along with ruined sinks and appliances scattered about the house and yard.  Leading from what appeared to be the kitchen area of the house was a  wooden log partly buried in the ground.  It was one foot in diameter and twenty feet long and  constructed of wooden staves shaped like slices of pie with the points cut off, then it was spiral-wound with a steel band for it's entire length.  It was a wooden pipe used to carry waste water away from the house. 

On the internet I found out it was likely made during World War I.  Steel was needed for the war effort so commercial pipe was constructed with redwood staves and spiral banding thus using much less metal.  Although made in 1916 or there-about it could have been installed much later than that. 

 12" wooden pipe with a 6" internal diameter.

Over a century old this pipe belongs in a museum.

THE McCAULEY SINKS

While flying around on Google Earth I came across these holes in the grasslands twenty miles south by southeast of Winslow, Arizona. At first I thought they were bomb craters but they were different sizes and laid out in arcs which didn't seem right. Then I thought they might be a cluster of meteor impact craters; after all the Canyon Diablo Meteorite struck just 30 miles west of here. After an internet search I found out they are the McCauley Sinkholes and a unique geologic site in Arizona. 

Over 272 million years ago the northern edge of the Pedregosa Sea repeatedly flooded the area. As the sea retreated a layer of evaporates (calcium, gypsum, or halite) was left behind. The layer later covered by the eolian Coconino Sandstone and then by the Kaibab Limestone. Ground water is slowly dissolving the evaporate layer salt bed leaving cavities for the overlying rock to collapse into. 

There are about fifty sinkholes in a one square mile area. Some are just faint depressions that may deepen in time and others are a few hundred feet across and eighty feet deep. The largest one is the size of a professional football stadium. There are two more smaller clusters of sinkholes eight miles and twenty-six miles to the southeast of the McCauley Sinks.

 Chevelon Canyon and creek run nearby.

  A sinkhole 600 feet long, 350 feet wide and 80 feet deep.

The McCauley sinks are on private land and I have never visited them so I only have Google Earth images.  Access is permitted by contacting Brantley Baird at the Rock Art Ranch, (928) 386-5047.  Also on the property is an old west memorabilia museum, numerous Indian ruins, artifacts and petroglyphs.  They welcome visitors for a fee and a guide accompanies all visitors.  Additional information and directions can be found online.

Location of the sinks is on neighboring property at 34˚ 47' 55'' N 110˚ 35' 13'' W

THE HOLBROOK CRACKS

The Holbrook Cracks is an area located in the grasslands about 15 miles southwest of Joseph City, Arizona.  It is locally known as The Cracks, or Holbrook Cracks or even the Joseph City Fissures. Whatever you call it the place is fascinating.

Coconino Sandstone is the white rock that is fracturing at the Cracks and is likely about 700 feet thick. Below that layer is the Schnebly Hill Sandstone visible as the red cliffs surrounding Sedona, Arizona.  Midway into the Schnebly Hill Sandstone is a relatively thin layer of limestone known as the Fort Apache Limestone.  It is approximately one-quarter mile (1,320 feet) beneath the surface.

The Fort Apache Limestone layer was deposited by an extension off of the Paleo-Pacific Ocean known as the Pedregosa Sea.  It withdrew and evaporated over 260 million years ago leaving behind the limestone layer of marine organisms up to one hundred feet thick at The Cracks.  In the red cliffs at Sedona it is about 20 feet thick and is visible as a gray band and shelf in many locations because it is harder than the Schnebly Hill Sandstone and acts as a capstone that retards erosion.

This limestone layer is believed to be the cause of the surface cracking in conjunction with an anticline and ground water.

Anticline

As the limestone layer is dissolved by acidic ground water the sandstone layers above become unsupported and try to slide off of the peak of the anticline.  The cracks are opening in the Coconino Sandstone at the peak of the anticline.  They range in size from tightly closed fractures in the rock to fissures 10 feet wide that likely extend down 1,300 feet to the limestone layer below.  A 10 foot wide crack at the surface narrows quickly with depth and is quickly filled with rocks sloughing off the walls and windblown sand.  The deepest one I know of so far is about 150 feet.

The cracks form in complex patterns over at least a four square mile area. Surrounding the area of the cracks are encroaching sand dunes where cracks also appear in inconvenient places, like across the road.

The question I have is why would there be an anticline at this location?  Anticlines are generally formed by compressional tectonic forces on the land that create long bows and folds in the earth.   Yet the Colorado Plateau is known for its stability and lack of such features.  Standing on the hill where the Big Crack is found and looking out over the area of the cracks, it is a domed area rising above the surrounding terrain like a giant zit.

An anticline is a domed feature if looked at in a two dimensional cross-section but they are three dimensional features, (refer to the illustration above).  I can only think of two reasons for a two dimensional dome to occur; a salt dome pushing up from below or a plutonic intrusion from far below.  It's just food for thought.
  

There are also sinkholes forming around the vicinity of the cracks.  On the dirt road approaching from the north I drove through several natural shallow depressions where water flows in but there weren't any outflow channels.  This is a tell-tale sign of karst topography and limestone caverns below.

So there is some complex geology going on at The Cracks on the surface and underground: surface fracturing, domed hills, a possible anticline, karst topography, caverns and sinkholes.  It makes interpretation difficult.

Google Earth satellite photo of just a small area of The Cracks.

In one of the larger cracks, Arizona Public Service, the states electrical power company, dumped construction debris into it when the transmission towers from the Cholla Power Plant were raised to deliver electricity to southern Arizona.  The power lines pass directly over the area of the cracks and a dirt maintenance road follows the power lines.

Straping, wire, insulators, etc. 

I found that when I drove under the high voltage power lines the electrically charged air also charged the metal frame of my quad.  If I touched any part of the frame it would shock me like a 9 volt battery held to the tongue. The quad would also periodically just shut itself off and I would have to restart it.

Crack next to the road.

Ryan looks for the bottom.

Crack 6

Ryan's Hangover

To dark and deep to see the bottom.

The Big Crack is about 10 feet at its widest point.

This is not a place to take children, pets or to travel at night.

In December Mike Eilertsen from Snowflake, Arizona contacted me about taking his eight grade  STEM (Science, Technology, Engineering, Math) class to The Cracks.  On February 7th, 2020 I met them near the cracks as an unofficial guide and driver.  Mike with nine students, one parent and a drone driver, Mathan Tenney, showed up and spent the day taking drone videos and lowering a remote control vehicle (RCV) with lights and a video camera into two different cracks.  The RVC was not purchased but designed and built by the class.

It was a project to be entered into a yearly national STEM competition.  They had won the contest three years ago and were making another attempt.  I greatly enjoyed being of help and observing their project.

White Mountain Independent newspaper article

Class Video

School teacher Mike Eilertsen

Junior High School STEM class of the Snowflake Unified School District

The Remote Controlled Vehicle (RCV)

Lowering the RCV via a pulley and parachute cord.

The RCV has an umbilical supplying power from a generator.

Mathen Tenney and his drone

Microbial soil is abundant throughout the area of the cracks so avoid walking on it as much as possible and stay on the rock. Microbial soil is a crusty mat of bacteria and fungi that helps to hold the soil in place and retards erosion. You cannot see it but if the soil crunches when you step on it then it is there.

Lichen growing on colorful sandstone.

Blue, yellow and green lichens are growing on many of the rocks so try not to step on them either. Lichen is a plant that grows about 1 millimeter per year and it is sometimes used by archaeologists to date recent human activity.

Desert varnish can also be found on some rocks in the area. It is a red to black patina found on exposed rock surfaces in arid regions. Composed of clay minerals, iron and manganese oxides as well as other trace elements, it is deposited slowly over time by moisture and wind blown dust. This layer is the thickest I have ever seen and it looks as if the rock had been clad in iron, which indeed it has. This deposit is sloughing off in plates as it is sandblasted and undermined by strong winds. 

Desert Varnish

 The Cracks cover an area about 4 square miles.

I've mapped the roads and locations of some cracks. The green line is the primary dirt road through the area that follows dual high voltage power lines.  The yellow lines are side roads to other areas of the cracks and to a third power line.  The brown line is a hike up a dry, sandy wash.

Finding The Cracks in not easy and getting there is even harder.  There are 15 miles of unmarked dirt roads and deep, loose sand and rocky terrain once you arrive there.  The dirt bike bogged down in Big Sandy Wash but the four wheel drive quad was able to keep going.  A HIGH CLEARANCE FOUR WHEEL DRIVE VEHICLE IS ABSOLUTELY NECESSARY AT THE CRACKS.  BE PREPARED TO SELF RESCUE FROM THE SAND!

The cracks are on the Rock Art Ranch but they allow access.  Leave any gates as found to keep cattle where they belong.

The GPS location is:     34˚ 49'  18''  N          110˚  27'  03''  W

LAVA TUBES AND PITS

Over 400 volcanoes and a veneer of lava flows, known to geologists as the San Francisco Volcanic Field, cover an area fifty miles long and thirty miles wide around Flagstaff. There are places in the lava flows where a crust formed over molten rock which then drained away and left hollow tubes and pits. Some of this cavities have collapsed and been found and certainly others have not. In addition underneath all that lava is the Kaibab Limestone where caverns tend to form.

Lava River Cave

The best and most famous lava tube in the state of Arizona is Lava River Cave, originally known as Government Cave. It is three-quarters of a mile long, in places thirty feet in diameter and splits into two smaller tubes then rejoins.  The roof caved in long ago in such a way that it revealed the upper branch of the cave but large boulders blocked the downhill rest of the cave.  How far the downhill branch may continues is unknown. 

It is truly a marvel among lava tubes. There are  11,000,000 hits about it on the internet and a deluge of photographs.  I don't think it necessary that I go into in depth here, pun intended.  I have been to it a dozen times since I was a teenager and never taken a decent photo of it. The photos I have included here I plucked off the internet.

The roof collapsed to reveal an entrance to Lave River Cave 

 

The tube splits into two smaller ones then rejoin.

For a lava tube to form the eruption stops and the still fluid molten rock drains out by gravity or the vent sucks it back down into the earth or both.  In any case a hike into Lava River Cave is well worth the geologic adventure.  

There is an element of risk.  There is ice covering the rocks just inside the entrance even in the summer.  It is a rock scramble for the first hundred feet or so and loose rock litter the floor in some places.  There is an ever present danger of rock slabs falling from the ceiling although none have been known to since its discovery in 1915.

Wear warm clothes, boots and take two flashlights per person. Its location is 14 miles out Highway 180 towards the Grand Canyon. Turn left on Forest Service Road 245 for six miles. Turn left on FS 171 for one mile. Turn left on FS 171B and it's .4 miles to the cave. This is a popular place so don't expect a private experience.

Scholz Lake Lava Tube

Scholz Lake was formed when an earthen dam was built most likely around 1916.  The U.S. Government contracted for hundreds of ponds and lakes to be created on federal lands all over the southwestern states.  This encouraged ranchers to raise herds of cattle to feed the Allied troops fighting in Europe during World War I.

After the dam was built snow melt and rain water flowed into the lake but it only reached a shallow depth and wouldn't fill.  Engineers found a lava tube at the far end of the lake where the water was draining out.  A sizable pile of drift wood had plugged the entrance but not tight enough to stop the flow of water.  They had to built a second damn as a berm surrounding the mouth of the lava tube so the lake could fill.

       

A grass covered berm surrounded the entrance to the lava tube.

I paddled my kayak around the lake and saw the earthen berm but couldn't tell why it was there. I didn't want to get out of the kayak because the mud along the shore was so deep and sticky.  The next time I went to the lake I walked the 2.8 miles around it so I could see what was behind the berm.

The berm with the lava tube to the right.

Boulders had fallen down partially hiding the entrance to the lava tube. 

The entrance was completely plugged by drift wood.  

Looking at the berm and lake while standing over the cave entrance.

How large the lava tube is and how far it back it goes is unknown.  It would take a huge effort to remove the driftwood.

Sunset Crater Lava Tube

There is also a lava tube at Sunset Crater but it was barred in 1973 because the ceiling was in danger of collapsing. Aren't they all? I crawled into it in 1962 but had no light so I didn't go far. 

The entrance to the lava tube at Sunset Crater is permanently barred.

There is a nature walk through the park on the North and South Lava Trails where you can see other volcanic features such as the Bonito Lava Flow, lava blisters and spatter cones.   

Paradise Forks Lava Tube and Collapse Pit

Southwest of Flagstaff halfway to Williams is Paradise Forks, a popular rock climbing area. It is at the head of Sycamore Creek which has cut deeply into thick lava flows exposing the vertical shrinkage cracks that climbers enjoy.

Opposite the climbing walls on the other side of the canyon is a plugged lave tube.  Sometimes as lava cools it thickens into a blocky flow called  a'a that can't drain out of the tube.  It solidifies into a plugged tube of poorly consolidated rock.  If erosion exposes the tube it may be recognized as a circle of noticeably different rock that crumbles faster than the surrounding denser lava.

A plugged lava tube erodes faster than the surrounding rock.

On the south side of the canyon, a quarter-of-a-mile past the climbing walls is a collapse pit 200 feet across and 50 feet deep. This was a lava cauldron that started to cool and formed a solidified cap. Then the molten rock either drained or was sucked back down into the vent and left a cavity hidden beneath the hardened cap. It held suspended for a few million years before it collapsed in the last few centuries. The jumbled rocks in the pit have not formed the rusty colored coating like the far wall has, indicating it hasn't been exposed to oxygen and moisture very long.

Collapse Pit

Lava Tube 231

I was driving on Woody Mountain Road 231 when I noticed this depression in the ground next to the road so I stopped.  At the base of the rock ledge I found a hole that appeared to be an opening into a lava tube. There was a strong flow of cold air coming out the hole so I thought it must lead to a sizable cavity.  It is on the right side of the road a little more than a mile past Rodger's Lake.

Lava Tube 231

Standing in the opening.

 Each leg of the triangle is about 18 inches long.

The hole is too small for me to fit through so I told a spelunker friend of mine about the opening I had found.  He did squirm into it and found a lava tube but since he was alone he didn't explore it.

Arrowhead Sink

Arrowhead Sink is a limestone sinkhole that formed underneath a thick lava flow.  The roof of the limestone cavern and lava cap both eventually collapsed creating a hole 130 feet deep. At the base of the lava flow are three lava tubes. All three are plugged but one is a cave about fifteen feet deep that was used as shelter by Native American Indians.

Arrowhead Sink and the 1st lava tube on the right.

 1st lava tube is plugged.



2nd and 3rd Lava tubes at the base of the rock wall.

The tube on the right goes back 15 feet and has smoke stains on it's ceiling.  NA612 is written in white paint on the rock over the cave.  I assume it is an identifier as an archaeological site which has already been excavated.  No artifacts remain in the cave.

Cave NA612

The I-17 Lava Tube

A lava tube was exposed in the 1970's when the road bed for the I-17 freeway between Flagstaff and Camp Verde was being excavated. Drillers were boring holes to set explosives when the drill bit punched through the ceiling of a lava tube.

The contractor thought it necessary to cover the opening behind a concrete barrier which you can see today as you zip past at 75 miles-per-hour.  In the same road cut there are two other lava tubes that didn't drain but still left a small gap at the top of the tube.

 

The intense heat of the molten lava melted the ceiling which dripped and
formed small stalactites like frozen 'rocksicles' hanging from the ceiling.

Angular rock shards on the floor were blown in when the hill was dynamited.

Over the centuries a layer of calcium carbonate precipitated onto the floor of the tube.

The road cut with the lava cavities is located at mile 306.5 in the south bound lane north of the Stoneman Lake Exit.  If you pass this sign heading south you've gone too far, the road cut is behind you.

San Francisco Wash Lava Tube

The opening to lava tubes sometimes made attractive homes for Native American Indians in the past.  This small pueblo is in the mouth of a lava tube in the San Francisco Wash east of Flagstaff.  The Indians used the lava rocks to build the walls of the dwelling.

San Francisco Wash

The lava flow and tube are on top of the Kaibab Limestone.

Pueblo walls

 Built by the Sinagua Indians and abandoned in the 1500's 

This Indian dwelling has certainly been plundered in the past and no artifacts remain.