Monday, February 14, 2011



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” ( 

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”. 


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.