At noon in the desert a panting lizard waited for
history, its elbows tense, watching the curve of a particular road as if
something might happen. William Safford
During my sojourns to Arizona for the February rock
and gem shows, I usually try to camp at, and explore, the numerous state and
county parks that dot landscape in the metro Phoenix and Tucson areas. I have posted on several of these sites
including Picacho Peak, the Superstition Mountains, the Santa Catalina Mountains
and recently the travertine north of Cave Creek and Carefree.
Cave Creek is one of my favorite small towns, and by
the number of motorcycles and horses on weekends, the favored town of bikers and rodeo fans. It has some great small watering holes and a
plethora of interesting eating joints catering to a wide variety of
tastes. I mean who could pass up a craft
brew and a juicy burger at Big Earl’s Greasy Eats. Cave Creek is trying to hold on to their
western style and attitude while keeping down careless zoning and macmansions. Unfortunately there seems to be a big battle
between wantabe developers on Black Mountain and conservationists trying to
hold the line on desecration of a beautiful piece of property. Cave Creek is also home to one of my favorite
magazines, True West.
Next door is Carefree, home to massive golf courses
and majestic houses and merging into trendy Scottsdale on the south. The two small towns (C & C) are a contrast in
development and preservation. What they
both share, however, is a need to manage urban sprawl, including water
resources, extending north from Phoenix and its suburbs. Cave Creek and Carefree are really the
northern boundary of metro Phoenix until one migrates west toward Interstate 17
and the Anthem-New River area.
Valley of the Basin and Range south of Cave
Creek/Carefree. Notice development.
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The Basin and Range area from the communities south
is characterized by wide valleys with intervening north-south trending fault-bounded
(usually) mountain ranges--see photo. This far
south in the Province the ranges are highly eroded and have contributed a huge
amount of sediment to the fault-bounded (usually) valleys. In some
localities the mountains have been almost completely buried by the shed
sediments. The rocks in the mountains
range in age from Precambrian to Cenozoic.
Many of the valleys contained, at one time or another in the Cenozoic,
fresh water lakes and numerous volcanoes and vents spewed out various extrusive
igneous rocks (Leighty and others, 1997).
When sitting in an outdoor café in Cave Creek one
cannot but help notice the massive high hill blocking the south view from town---Black
Mountain. Unfortunately it seems that “money”
can buy property and roads are slowly snaking up the mountain and “spoiling”
the views for thousands of others. But,
such is life I suppose!
· Black
Mountain (from the south) with dark colored meta argillite and phyllite on the
left intruded by granite exposed on the right.
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The name of Black Mountain comes from the western
side where very dark gray to black phyllite and meta-argillite crop out---not
basalt as some people in town will tell you. The protolith, that is the
original rocks, were sedimentary mudstones,
siltstones and shale that were subjected to metamorphic processes like heat and
pressure during their long burial and subsequent intrusion by the granitic
batholith. These rocks are Early
Proterozoic in age and mapped as Precambrian X (Leighty and others, 1997);
however, in the current stratigraphic terminology X refers to rocks of the
Paleoproterozoic with ages ranging from about 2.5 Ga to 1.6 Ga. Again, the Ga refers to billions of years
before present. They dip steeply to the
west (probably due to sliding off the granite) and are nicely exposed in
outcrops along Cave Creek Road heading into town.
West dipping metasedimentary rocks near Black Mountain.
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The east side of the Mountain exposes coarse-grained
granite of Middle Proterozoic age, mapped as Precambrian Y. Today these rocks would be termed
Mesoproterozoic with an age range of approximately 1.6 Ga to 1.0 Ga. The granite is actually part of a large
batholith that extends in the subsurface to the south but reappears in other
localities such as the famous Phoenix landmark, Camelback Mountain.
Coarse grained Mesoproterozoic granite.
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There is a large granite pediment to the east of the
Mountain where the rock is easily erodible into grus, that is pebble and pea size hunks
of eroded granite. (Leighty and others, 1997).
But, there are some really great hills of rounded granite boulders
sticking up through the eroded pediment.
Boulder inselbergs, Mesoproterozoic granite.
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I have tromped through the area around Cave Creek
and noticed numerous mining “holes,” pits, and tailing piles; however, the
early prospectors were not overly successful.
Apparently they were looking for gold or copper (some green coatings on
rocks) and some areas did give up minerals.
The Phoenix and Maricopa mines directly north of Cave Creek produced
about 17,000 ounces of gold, and actually supported a 100 stamp mill and
cyanide leaching operation (Wilson, 1934). On Black Mountain itself the Mormon Girl Mine
was a lode gold mine and out near the Cave Creek Campground the Go John Mine
was an active lode operation. I even
tried panning for placer gold in some of the stream beds where I could locate a
little water after a rain; however, bending over a pan is tough on the ole back
when the flakes are absent! The only evidence of mineralization that I
have observed were some outcrops where the Precambrian X rocks are composed of
specular hematite. I don’t believe that area
rocks were ever mined for iron.
Entrance to Clay Mine at Cave Creek Regional Park.
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I suppose the most successful mine in the area is located
west of town in the Cave Creek Regional Park operated by Maricopa County. A hundred yards or so from the campground is
the remnant of the Clay Mine. As with
most early prospectors, the guy (I presume guy) was searching for gold along a
clay/talc zone in the dipping Precambrian X rocks. My initial examination and statement (to
myself) was something like “why in the world would he dig here, I see
absolutely no indication of mineralization.”
I guess that was a correct assumption in that the mine did not produce
gold. But, it did produce wealth for a
later owner by the name of Leila P. Irish.
Ms. Irish decided to mine the clay, mix it with water and then sell the concoction
as a miracle elixir, something that would cure any and all ailments. According
to the local historians, Ms. Irish became quite wealthy, an innovative snake oil
saleswomen. I tried it out with my own
mixture and just about upchucked! Whatever,
it takes to make money, I guess.
REFERENCES CITED
Leighty, R.S., S.J. Shotnicki and P.A.Pearthree, 1997,
Geologic Map of the Cave Creek Quadrangle, Maricopa County, Arizona: Arizona Geological Survey OFR-97-01.
Wilson, E,D., J.B. Cunningham and G.M. Butler, 1934,
Arizona Lode Gold Mines and Gold Mining:
Arizona Bureau of Mines Bulletin 137.
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Nice post, thank you. I find myself wondering how one differentiates argillite from shale.
ReplyDeleteMy husband found your article and we can't wait to explore this area but maybe on a cooler day; we recently moved here from Colorado Springs . Very interesting article about the rock formations...thanks!
ReplyDeleteThose who want to learn more about the local geology can see a presentation at...
ReplyDeletehttps://www.dflt.org/courses/armchair-tour-of-the-jewel-of-the-creek-preserve