HOHOKAM PETROGLYPHS

A DANGEROUS HUG!

One of the really interesting locales in south-central Arizona is Casa Grande Ruins National Monument near Coolidge (about one-half way between Tucson and Phoenix).  The site was given the designation of archaeological reserve by President Benjamin Harrison in 1892 (the first such designation).  In 1918 President Woodrow Wilson declared the site a National Monument.  The National Park Service (NPS) refers to the inhabitants and builders as Ancient Sonoran Desert People but most people simply call them the Hohokam.  They evidently were agrarian people and farmed the desert with the help of an extensive system of canals, mostly along the Gila and Salt Rivers.   The NPS believes the Hohokam lived in the area for over a thousand years until around 1450.  At Casa Grande the people built a "big house” (Spanish = casa grande) that the NPS believes is one of the largest prehistoric structures ever built in North America; remains of the four story “house” are still visible today.

While hiking with, and following, my brother in the hills south of Casa Grande (I was actually looking for zeolites in the basalt) we were treated to the sight of hundreds of Hohokam petroglyphs, and foundations of some sort of ?buildings.  While the buildings at Casa Grande are composed of caliche, all we observed were rock foundations.

 

I have observed numerous petroglyphs (“pecked” into rocks) and pictographs (painted on the rocks) in the red rocks of the Colorado Plateau, and even in my native Kansas on the Dakota Sandstone.  The Colorado Plateau glyphs and graphs are the work of artists associated with the Barrier Canyon Culture and the later and better known Fremont Culture.  However, this is the first time that I have observed glyphs on basalt boulders.  But, I guess artists work with the media available!

mike

A BUILDING FOUNDATION?

LIZARD GLYPH

A STORY WITH A LIZARD

BIGHORN SHEEP

SANTA CATALINA MOUNTAINS

SANTA CATALINA MOUNTAINS LOOKING EAST FROM STATE PARK.  BOUNDING PIRATE FAULT RUNS THROUGH AREA IN FOREGROUND.

The Santa Catalina Mountains dominate the skyline east of Tucson and are a typical Basin and Range chain with large bounding normal faults on either side.  West of the Catalinas (along the highway) is the Canada del Oro Basin, a graben filled with several thousand feet of sediments eroded off the high mountains.  The coalescing alluvial fans (debris shed off the retreating mountains) from the Catalinas seemed to have merged with similar fans coming off the Tortolita Mountains (west of the Basin) about one Ma (Bezy, 2002) (Fig. 6).  Most of the sediment in the Basin is composed of pieces of granite, schist and their mineral components such as feldspar, quartz and muscovite.  This seems logical since the western mountain front is composed dominantly of different types of granite emplaced during the Precambrian (Oracle Granite, 1.45 Ga) and the Tertiary (Wilderness Suite Granite, 45-50 Ma; Catalina Granite, 26 Ma) (Bezy, 2002) (Fig. 7).

The major drainage along the western front of the range is the south-flowing Canada del Oro with tributaries coming down from the mountains and joining it at right angles.  Most likely this rather straight-flowing stream follows the course of the western bounding fault termed the Pirate Fault.   Mt. Lemon at 9157 feet is the highest point in the Catalinas and has a ski resort---not a very good proposition in most dry winters.  The name, Santa Catalina, may have been bestowed by a Jesuit priest, Eusebio Francisco Kino, who was busy converting the Tohono O’odham (local Native Americans) to Catholicism in the late 1600’s.  As with many places in the west, Spanish miners soon followed in the footsteps of the proselytizing priests.  They evidently found placer gold in a creek and named it Canada del Oro or Gulch of Gold, a name that has intrigued me for the several years that I have been coming to Tucson. 

The area also has its share of lost mine stories, although nothing to quite match the Lost Dutchman up at Apache Junction.  Most of the tales seem concerned with the Iron Door Mine (gold) and La Esmeralda (silver) in the northern section of the Catalinas.  Clay Thompson of the Arizona Republic in the 10 December 2007 edition reported: “at some point in the 1750s or 1760s Jesuit missionaries feared for their lives, either because of a revolt by their Native American charges or because of attacks by the implacable Apaches.  So they stashed a whole bunch of silver and gold in either a mine or a cave somewhere in the mountains north of Tucson and sealed it with a heavy iron door - minas de fierro con puerta en la Canada del Oro. Then the Jesuits lit out for friendlier environs, and over time the exact location of the treasure was lost.

Lots of people have searched for it over the years, but obviously, no one has ever found it, if, indeed, it is there to be found.  One of the people who believed in the legend was Buffalo Bill Cody, who owned some mines in the area at one time and looked around a bit for the Mine With the Iron Door.

In 1923, a popular storyteller named Harold Bell Wright cranked out The Mine With the Iron Door, a novel featuring brave and honest prospectors, a plucky orphan girl, a wrongly accused hero and a couple of villains named Sonora Jack and Lizard.  The novel was made into a movie of the same name in 1924 and again in 1936.”

There is at least one region, the Southern Belle District but sometimes referred to as the Catalina or Oracle District, that actually has produced both lode and placer gold.  The mine, “a former surface and underground Au-Pb-Ag-Cu-W-silica mine”, evidently was closed in 1964.  “Mineralization is a tabular ore body” hosted in rocks of the Precambrian Apache Group (exposed between the Oracle Granite and the Catalina Granite).  Mineralization in the quartz veins “is probably associated with a Lower Cretaceous-Tertiary intrusive period” (www.mindat.com). 

I have thus far been unable to gain access to the Southern Belle property, so I did the next best thing—grabbed my gold pan and tried to locate a placer deposit in Canada del Oro.  I did find a single small piece of flour gold but not much else.  Toole (2007) suggested that since the stream course contained 60-200 feet (actually I think it is much greater) of “overburden” then the gold would be down on the bedrock.  But he also opined that perhaps a metal detector (which I do not own) could locate surficial nuggets. 

My lack of success with the pan is probably the norm for Canada del Oro.  It appears that for several years after members of the local Native Americans quit discouraging exploration, miners tried to make a living with placers but activity seemed unsustainable over the long term.  Wilson (1933) reported “numerous old pits, trenches, and tunnels indicate considerable early placer mining, and many thousand dollars worth of gold are reported to have been recovered.  The production recorded from 1903 to 1924, inclusive, amounted to $11,351 [this was at $20 gold] …During the 1932-1933 season, approximately thirty men intermittently carried on small scale rocking and panning in the Canada del Oro region, chiefly on the northern side of the creek.  Although one $25 nugget [1.25 oz] and a few $5 nuggets [.25 oz.] were reported, the average daily returns per man were seldom more than fifty cents”. 

REFERENCES CITED

Bezy, J. V., 2002, A Guide to the Geology of Catalina State Park: Arizona Geological Survey, Down-to-Earth 12.

Toole, D., 2007, Where to Find Arizona’s Placer Gold: Delos Toole Gold Books, Salem, Oregon.

CANADA DEL ORO BASIN IN MIDDLE DISTANCE.  LOOKING WEST FROM CATALINA MOUNTAINS WITH TORTOLINA MOUNTAINS IN FAR DISTANCE.

GOLD, GOLD, GOLD AT TUCSON

CALIFORNIA GOLD

CALIFORNIA GOLD NUGGETS

MORE CALIFORNIA GOLD

51.2 POUNDS OF AUSTRALIAN GOLD

ANOTHER PERSPECTIVE

GOLD "FOR SALE"

Today, 10 February, was the opening day of the annual Tucson Gem and Mineral Show held at the Tucson Convention Center.  As usual, parking in downtown Tucson was aggravating and difficult; however, I was there shortly after the opening bell.  The show’s theme, Minerals of California, would indicate the presence of some fantastic specimens of Elbaite, Benitoite, and Gold and I was anxious to observe.  I was not disappointed and could only gaze in wonder at some of the most beautiful minerals in the world.  However, the star of the show may have been the 51.2 pound Ausrox gold nugget from Australia.  It was hard to realize that the monster was an actual piece of solid gold; my brain failed and was unable to convert pounds to ounces times $1364 spot plus the bonus for specimen gold!

TUCSON ELECTRIC PARK SHOW

The Tucson Electric Park/Kino Sports Complex Gem and Mineral Show is an event held prior to the main Tucson Gem and Mineral Show and is a gathering rock hounds will not want to miss if in the Tucson area.  The Show, usually held the first two weeks of February at the sports complex, is just off I-10 in the southern part of town.  There is no admission charge and an advertised 20 acres of free parking complete with shuttles— major selling points for a fun and inexpensive time.   Well over 250 vendors display wares at the Show and that is the main attraction---the funky items for sale are diversified, to say the least.  There are large jade tigers, at least a million beads, chairs constructed from petrified wood logs, enough dop sticks to supply the CSMS group for decades to come, thousands of pieces of costume jewelry plus some high end blue topaz (guaranteed non-heated treated!), the largest tumblers in the world, wooden canes, “Navajo” rugs with a tag stating “Made in PRC (China), trilobites by the thousands (including numerous fakes), the self described Amethyst Capital of Tucson, and since this is Arizona—several rifles and pistols.  I was somewhat fascinated with the fake trilobites as most were really bad—the bugs were cast in a black resin and then cemented to a gray limestone with matching gray cement.  Put on a few tool marks and throw it on the “For Sale” table.

On the other hand, there were some really nice mineral specimens for sale at reasonable prices.  I found the best displays, and the least expensive minerals, at a section of the event called the RV Show. This area included “mom and pop” shops, and individuals, both living in their parked RV’s and displaying their collections on tables.  Most were very interested in visiting with potential customers and many had some very nice specimens.  This frugal rock hound was able to purchase some really nice water-clear, yellow-orange, wulfenite crystals collected from the “79 Mine, 4^th level, Hayden, Gila County, Az” for $1!  A collector who lives near Grand Junction, Colorado, was showing, and selling, a fantastic collection of Utah Lace Opal collected from his claim near Milford, Utah.  But perhaps the most impressive specimens, at least to me, were some of the giant crystal quartz points collected in Brazil.

So, everything at the show is free to look at and the parking is easy and free—a great way to spend an afternoon or a day.  The displays are often quirky and who would not want to take home some genuine plastic turquoise beads.

mike

Carved Tiger

Petrified Wood Chair

Take Home A Crystal Skull

A Quite Large Quartz Crystal Point

Buy Your Genuine Coon Skin Hat

Always an Amethyst Cathedral

CSMS 2011 OFFICERS

CSMS 2011 Officers

The annual CSMS banquet and officer installation was held 20 January at the Best Western hotel in north Colorado Springs.  President Ron "Yam"Yamiolkoski passed the gavel to incoming President Roger Pittman (who also served a few years ago); however, Yam will continue on the Board as Past President and 2011 Show Chair.  Other officers include Kay Thompson--Vice President; Ann Proctor--Treasurer; Joan Peterman--Secretary; Roni Poteat--Membership Chair; Teri Stoiber and Ann Proctor--Editors; Sharon Holte and Al Zelenak--Members at Large.  Life Member Ray Berry administered the "oath of office".  Bob Germano, Jennifer Beisel, David Olsen, and Drew Malin rotated off the Board (thanks for the service).  The Society also was honored by the attendance of several life members, including Roy Wilson (50 years), Kay Thompson, Eloise Berry, Charles Webb, Steven Veatch, Raymond Berry, Jack Thompson and Michael Wheat.  Mike Nelson gave the address, "Geology and Physiography of Colorado".  Frank Rosenberg serves as the "official" photographer.

mike

Life Members with Roy Wilson holding the pick

Yam and Roger

Bill & Betty Cain, active in the Rocky Mtn. Federation

 

 

                                           

SIGNAL BUTTE: A GEOLOGICAL ODDITY

SIGNAL BUTTE IN THE FALL.

Traveling along county roads west of Woodland Park, Colorado, travelers may spot a rather out-of-place conical peak, Signal Butte (another name, according to the USGS GNIS is Cheops Pyramid).  The peak, not really a butte at all (butte = an isolated, limited tableland capped with a horizontal and protective covering; Thornbury, 1962), is not readily visible from U.S. 24 nor from the lowlands of CO 67 north of Woodland Park.  Signal Butte is located at Lat. 39.05860 degrees N and Lon. 105.2228 degrees W and is best accessed from Divide—north on Teller Co. 51 for 11 miles, right on FS 363 (Phantom Creek Rd.) for 0.6 miles until FS 362 (Signal Butte Rd.) for 3.3 miles.  There is a small parking area and the route to the summit seems obvious.  One can also access the Butte from CO 67 near Westcreek; however, the roads are 4-wheel drive, several are washed out, and most of the land is private.  Whatever the route, the Butte is obvious as a distinctly shaped conical peak at 9459 feet in elevation and nearly a thousand feet above the adjacent creek.

AIR PHOTO OF SIGNAL BUTTE.  FROM MAP CARD.

 From a geological point of view, Signal Butte is interesting as it exposes middle Tertiary igneous rocks (~1/4 sq. mile) almost in the center of the massive Pikes Peak Batholith (~1300 sq. miles, Tweto,  1979).  The Precambrian Batholith (~1.1 Ga), with exposures of pink granites and pegmatites, has been intruded (igneous magma cooling below the surface and within the granite) by gray colored igneous rocks “of felsic to intermediate composition with an age of 20-40 M.Y.” (Tweto, 1979).  I have been unable to locate much additional geological information about Signal Butte but will continue to search the literature.  The rocks that I collected from the Butte are dark gray in color, and with a texture close to aphanitic (fine-grained) to porphyritic (larger crystals within the groundmass) with visible lathes of feldspar crystals.  Wilson and Bryant (2006) stated the rocks at Signal Butte were a “pyroxene-hornblende trachydacite” from a “plug”.   Trachydacites contain major amounts of sanidine feldspar with minor quartz.  The Signal Butte rocks contain the accessory minerals pyroxene [group] and hornblende.  If Wilson and Bryant (2006) are correct and the Butte is a plug then the magma crystallized in a neck and/or volcanic vent.  At a later date, erosion removed the surrounding granite and the plug was left as a major landform.  Perhaps the rocks are hypabyssal and cooled in an intermediate position between the surface and deep within the crust---the volcanic neck never reached the surface.  That might explain the somewhat larger crystals (larger than basalt crystals)  in the rocks that I observed.  Please understand that I am out of my comfort zone describing the probable origin of Signal Butte without a more detailed study.  However, Tweto (1979) did show a fault extending north from the Butte; perhaps, the magma came from a zone of weakness in the granite. 

TRACHYDACITE CROPPING OUT AT SIGNAL BUTTE.

                                                                                                                              

Wilson and Bryant (2006) have provided fission-track dates of 42.2 to 45.2 M.Y. for the trachydacites---an Eocene event.  That seems to be the approximate age of plugs near Boreas Pass west of Como but suggesting any relationship to these rocks are beyond my knowledge.  The dates do seem to be in the middle between the major igneous events of the Laramide Orogeny (~60 to ~80 M.Y.) and the outpourings of volcanic rocks in the Oligocene (~25 to ~30 M.Y.). 

Signal Butte is in the area devastated by the Hayman Fire of 2002.  This burn consumed forests and buildings on nearly 140,000 acres of land and caused damages in the tens of millions of dollars.  I did notice that some new pine trees have reached two feet in height and some aspens are now up to four feet so the forest is slowly returning.  However, it will take hundreds of years for the streams, now clogged with sediment, to return to some semblance of local base level and equilibrium.  A fantastic photo of the fire burning on Signal Butte may be observed on the Teller County website at: http://www.co.teller.co.us/HaymanFire/HaymanInfo.htm

Signal Butte has a fabulous view from the summit, is an object of geological interest that is close to Colorado Springs, and worth the easy trip to observe to some rather different rocks.  After all, how many of the readers have seen an example of pyroxene-hornblende trachydacite?

There is a trail to the summit and the hike is well worth the view, and, the rocks are quite interesting.

REFERENCES CITED

Thornbury, W.D., 1962, Principles of Geomorphology: John wiley and Sons, New York.

Tweto, O., 1979, Geologic Map of Colorado: U. S. Geological Survey, scale 1:500,000.

Wilson, A. B. and Bruce Bryant, 2006, Isotopic Ages of Rocks in the Northern Front Range, Colorado: U. S. Geological Survey Open-File Report 2006-1051. 

mike