Wednesday, October 21, 2009

Holes

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I've been trying to squeeze a few more miles into the alpine riding season up on Cedar Mountain. It just takes one good wet cold front to shut all riding down above 8000'.

Wanting a fairly long ride into uncharted territory (for me anyway), I planned to string a route together that linked several interesting things together that I've heard about or seen on maps, but have not yet visited.

Parking just off of the newly designated "Scenic Byway," HWY-143 at the turnoff for the Red Desert near Cedar Breaks, I first biked to Dead Lake. The dirt road was no problem on my mountain bike, but its boulder-choked surface will deter anyone else, save ATVers and jeepers who don't mind lots of bumps along the way.

If you can get here, Dead Lake would make a good fairly secluded place to set up camp and fish for a day or two.

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Continuing east past the lake, the Forest Service road drops quickly down toward the Mammoth Creek area.
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Above: what's left of the Heber C. Jensen sawmill below Dead Lake. This is where the lumber was secured to build the first building (Old Main) on present-day SUU's campus. Any past or present SUU student can tell you the story of Old Sorrel and the humble beginnings of the university.

In 1897, the Utah State legislature selected the fledgling Cedar City to be home to a new "normal" school, where teachers were trained, for the southern part of the state. Residents celebrated and classes began in the City's social hall in the fall.

Utah's Attorney General was not happy about the legislature's decision -citing a lack of adequate infrastructure in Cedar - and mandated Cedar to build a sizable structure to house the new school by the end of the next summer or the school would be moved to another city. This was announced just after Christmas, and city leaders knew they would need to obtain a large amount of lumber immediately if they had any chance to meet the deadline.

With no building materials on hand, the city desperately organized a winter expedition to obtain timber from near the Jensen Mill on Cedar Mountain. With snow up to 10' high at Mammoth Summit, the task seemed impossible. A strong and stubborn "sorrel" horse is credited with plowing through the deep snow to make the operation a success.

Dedicated in 1987, a large bronze statue on SUU's campus immortalizes this hoofed hero.


Past the mill, dropping down a seldom-used logging road into Mammoth Creek brings you to the mysterious Mammoth Springs. Here, the entire river erupts out of the dry creek bed.

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Above: the dry creek bed immediately above Mammoth Springs.
Below: the verdant and lively creek immediately below the springs.

Mammoth is the second largest spring in the state, and still holds the record for the largest instantaneous discharge. So where does this river of water come from? It is still somewhat of a mystery but based on the amount of flow and the fact that so much of the plateau top in this area exhibits a karst terrain, it's likely that a long cavern, enlarged fracture, or some other type of subterranean conduit is at play here.

Is there perhaps a whole network of unseen caverns and underground rivers lurking just beneath the surface on Cedar Mountain?

There is much evidence indicating that there is.

As part of a hydrogeologic study of Mammoth Spring, an important water source for the multitude of summer homes in the area, USGS scientists poured colored dye into a swallow hole 9 miles southwest of the springs. Typical travel times for water flow through an aquifer is on order of a few inches to several feet per year. In this case, it took the tracer only 27 days to travel 9 miles and show up at the spring! This indicates that the groundwater is not flowing through the rock but rather through cracks and caverns developed within the rock.

Also, Duck Creek, near the small town on HWY 14 with the same name, disappears into a series of sinks. For hundreds of yards, the creek can be felt and heard gurgling beneath your feet before it completely disappears into the unknown.

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After visiting Mammoth Springs, I followed a series of fire roads to Bower's Cave.

Above: the elusive Bower's Cave was a bit of a challenge to find. Unmarked on maps, and unknown to many Forest Service employees, your only clue to its whereabouts is this pole sticking out of a small crack in the ground.

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If you dare climb down the slimy entrance, you'll find a tall and linear subway-like cavern. This is a classic lava tube that forms when a sheet of flowing molten lava begins to cool and congeal. This occurs at different rates within the flow causing some areas to solidify while hotter lava continues to flow. Sometimes an arched tunnel structure of solid lava (basalt) will begin confining a river of lava. If the lava manages to drain out of the tunnel before solidifying itself, only the empty tube is left.

Bower's and the well-known Mammoth (see below) Caves are two such lava tubes on Cedar Mountain. Undoubtedly, there are many others that have not been discovered. The tubes are undetectable until a portion of the roof collapses creating a small window that can be found by a passerby.

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Above: a roof collapse in Bower's cave that does not quite extend to the surface.


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A tight squeeze is required to explore this side tunnel. Dressed in biking gear, and equipped with a single weak flashlight, I decided to save it for another day.


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Newly discovered singletrack! Well, sort of. There is a nice piece of trail leading to Bower's Cave that is open to bicycles, the downside is that it's only a few 100 yards long.

This latest ride to Mammoth Spring and Bower's Cave got me thinking of other holes and caves I've come across in the area:


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Above: Matt poses in the narrower but longer Mammoth Cave.


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Lava tubes don't account for all of the holes on Cedar Mountain. The Ice Cave (above) is a large solution cavity within the white member of the Claron Formation. Weak acids in rainwater are enough to dissolve the frail limestone, creating numerous sinkholes in the area. The cave has no lower outlet, thus collecting cold, heavy air in the summer that allows ice (visible in the bottom center of photo) to persist year-round.

Below: a large sinkhole near Cedar Breaks that roots into the Claron Formation.

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Cascade Falls on the southern edge of the Markagunt Plateau is another example of how rivers can almost magically appear out of nowhere in this region. This is the birthplace of the Virgin River that has carved the endless Narrows of Zion. It has long been thought that the river flowing out at Cascade Falls originates from nearby Navajo Lake.

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Could this strange circular feature near the shore of Navajo Lake be the "drain" that feeds Cascade Falls?

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