The Molly Marie Prospect is a group of 20 contiguous mining claims located in Maricopa County, Arizona.  This website describes the exceptional geologic features of the Prospect that includes a very large IOCG (Iron Oxide Copper Gold) ore deposit located in a previously unrecognized submarine caldera over one mile in diameter.

Below is a photo showing the extents of the massive iron-oxide altered breccias of the deposit before they dive under basalt to their east.  The abundant hematite breccias on the hill or bulge in the basalt dubbed “Cerro Negra” are not indicated, but are described within.  Please note the highway located approximately 600 yards to the west of the caldera.  The igneous rock exposed at the neck is  an oxidized magnetic, brick-red, Rhyolite porphyry; abundant iron-rich rock is a prerequisite for an IOCG.
The Molly Marie Collapse Caldera

Accompanying this deposit, located near the foot of the Superstition Mountains, is a subject that must be breached:

A “missing” mining district, The Peralta Mines.

The location of these legendary mines has commonly been thought to be deep inside the Superstition Wilderness area, but it’s just outside its boundaries.  All of the stories told about lost mines in the Superstitions during the past 125 years have one thing in common; they do not have any geology to back them up.  The geology of the District shown within proves the existence of the IOCG deposit, but proof that the District was mined by the Spanish and Mexicans (also shown within),  demonstrates that the IOCG deposit is the most sought-after kind………. an exceptionally  gold-rich one.

The root-cause of the richness of the deposit is likely the rock exposed at the volcanic neck, and what should comprise the magma chamber below: a  pre-enriched porphyry.  The below photo shows what a portion of the volcanic neck looks like.  The color of the porphyry betrays its high iron content.

Rhyolite Porphyry of the Molly Marie caldera

Proof that the Spanish and Mexicans mined the District also helps explain why a deposit so immense could go undiscovered; all of the most obvious outcrops indicating ore were simply removed and the pits (and shafts) were filled back in.

The nearby Goldfield mining District, 2-1/2 miles away, has geologic features similar to that  of the Molly Marie Prospect, including a caldera with breccias on its margin.  Significant gold ore was mined there, in breccias, that assayed hundreds of ounces of gold to the ton;  the volume of breccias at the Molly Marie caldera is multitudes greater than those at Goldfield.

The rareness of this type of an IOCG deposit exposed at the surface as shown below cannot be overstated. Below is a hand sample of rock from the Molly Marie that is exposed in a large zone approximately 400 yards long that is aligned with a major fault. The quartz there is very flaky and has the remains of pyrite and chalcopyrite.

Flaky Quartz and Hematite

Below is a larger sample, with more manganese mineralization and even heavier remnants of pyrite and chalcoprite.  Depending on your browser, click and zoom-in to see the mineralization.

Flaky Quartz, Hematite, and Manganese

Below is an outcrop of the flaky quartz, looking very benign, but with one hammer blow it reveals its secrets.

Flaky Quartz outcrop, peeking out from cover

The infrastructure of  the historic District and the potential for great wealth left to be unearthed is shown within.

After nearly 20 years of study and fieldwork, there is now enough evidence to present the mines that used to be, and where new mines could be.

Select any of the pages in the menu to begin……..

(cover photo is a view of the Superstition Mountains from the southern end of the Molly Marie Prospect)