The Sangre de Cristo Mountains of south-central Colorado are an uplifted, block-faulted chain of rugged peaks consisting of ancient Precambrian basement rock and younger Pennsylvanian-Permian sediments. The Precambrian rocks include truly ancient metamorphic country rock and slightly younger granites. These ancient Precambrian rocks constitute the core of the Sangre de Cristo mountain chain. Throughout most of its length, the crest of the range is capped by a thick sequence of tilted Pennsylvanian-Permian red beds. These beautiful maroon-colored sediments take on a distinctive ruddy hue during certain times of the day, hence the name Sangre de Cristo ("Blood of Christ"). The phenomenon is similar to the famous Swiss "alpenglow". The eastern slopes of the Sangres are also made up of these tilted Pennsylvanian-Permian sediments.
On the western side of the Sangres, Precambrian crystalline rock is exposed along the base of the range. Higher up the slopes, younger Paleozoic sediments lie unconformably upon the ancient Precambrian basement rock. In some sections of the Sangre de Cristos, Precambrian granite makes up the crest of the range. Examples include the Culebra Peak area, the Blanca Peak complex, and the Crestone Range.
The Sangre de Cristo Mountains were pushed
up along a set of high-angle thrust faults that pretty much run the length of the chain. Faulting began during Laramide times, but sporadic movement occurred throughout the Tertiary Period.
Rising up near the crest of the Sangres, Horn Peak is located on the eastern side of the range overlooking the Wet Mountain Valley. The entire Horn Peak area is composed of tilted Pennsylvanian-Permian sediments. Indeed, most of the Sangre de Cristo chain north of the Crestone Range is made up of these red-colored sediments. The Horn Peak area is cut by a major northwest-southeast trending thrust fault that extends roughly 12 miles along the eastern edge of the crest of the range.
The Horn Peak area is devoid of obvious mineral deposits. In fact, the entire eastern side of the Sangre de Cristos is generally lacking in mineral deposits. One must look to the western side for signs of mineralization. In virtually every mining district along the western edge of the Sangres, the ore bodies consist of gold-bearing pyrite veins emplaced within Precambrian metamorphic rock. In most cases, chalcopyrite is also present along with galena and sphalerite. In some cases, the schistosity of the metamorphic country rock controlled the localization of ore, at other times, faults and fractures served as the controls.
The Horn Peak area in the Sangre de Cristo Mountains of Colorado is truly one of the most beautiful spots in the state. It is also one of the most rugged. The peaks in this part of the Sangre de Cristos all exceed 13,000 feet in elevation. The geology of this rugged section of the Sangres is relatively simple and uncomplicated. The Horn Peak area is almost entirely overlain by Pennsylvanian-Permian red beds. This part of the range, and indeed the entire eastern face of the Sangres, is generally barren of mineral deposits. In the Horn Peak area, the northwest-southeast trending thrust fault offers the most promising prospects for mineralization. Faults make excellent conduits for ore-bearing solutions.
Prospectors may also want to focus on the western side of the range, along the headwaters of North Crestone Creek. This part of Sangres lies just across the divide from Horn Peak, on the San Luis side of the range.
This part of the Sangres seems to offer the greatest potential for future strikes. After all, the 1890 discovery took place nearly 20 years after the first strikes in the area. One wonders how such rich deposits of gold could be overlooked for so long. It is certainly possible that a small, undiscovered vein or pocket of gold-bearing quartz still lies hidden somewhere in the Crestone Creek drainage, just west of Horn Peak.