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 rock and slightly younger granites. These 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 crimson glow as the slanting rays of the sun strike the mountain slopes. To the devout Spaniards, these blood-red glowing peaks became known as the Sangre de Cristos. The eastern slopes of the Sangres are almost entirely 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. In some areas, the Precambrian rocks make up the entire western flank of the range, right up to the crest. In other areas, only a small band of Precambrian rock crops out along the base of the range. Higher up the slopes, younger Paleozoic sediments lie directly upon these ancient Precambrian rocks. In some sections of the Sangre de Cristos, Precambrian granite makes up the crest of the range. Examples include the Blanca Peak complex, the Culebra Peak area, and the Crestone Range. In some parts of the Sangre de Cristo Range, small exposures of younger Tertiary intrusive rock can be found. The largest Tertiary plugs occur 1] just south of Culebra Peak, 2] in the La Veta area, 3] along the western edge of Blanca Peak, 4] in the Cottonwood Peak area, and 5] in the Slide Rock Mountain area.
The Sangre de Cristo Mountains were pushed up along a set of high-angle thrust faults that pretty much run the entire length of the chain. Throughout most of the range, large faults form both the east and west boundary of the chain. Faulting began during Laramide times, but sporadic movement occurred throughout the Tertiary Period.
The Sangre de Cristo Mountains have never been significant producers of gold. The intense mineralization that characterizes so many of Colorado's mountain ranges is lacking in the Sangre de Cristos. The paucity of rich gold deposits in the Sangres has made them a "backwater" district in Colorado mining. But the mountain range does sport a number of mineralized zones along its western edge. In virtually every case, the ore bodies consist of gold-bearing iron and copper-iron sulfides enmeshed in a quartz gangue. Free gold is occasionally present. These gold-bearing veins are emplaced within Precambrian metamorphics and Paleozoic limestones in a number of locations along the western flanks of the range.
Modern-day prospectors who seek the Lost Golden Ledge of the Sangres join the ranks of hundreds of other prospectors who have been captivated by the legendary deposit. But the rugged Sangre de Cristo Mountains have frustrated and stymied every effort to find the elusive ledge.
The western face of the Sangre de Cristo range has been heavily prospected since the 1870's. No major bonanzas have ever been uncovered here. It seems unlikely that any premier gold deposits still lie undiscovered on the slopes of the Sangres. But prospectors must always remember that in 1890, nearly 20 years after the first strikes in the area, extremely rich gold-bearing quartz veins were discovered on the mountain slopes above Crestone. One wonders how the early prospectors overlooked these wonderful deposits of free-milling gold for so long.
Prospectors may want to focus their search on the richest section of the Sangre de Cristos, between North Crestone Creek (near Crestone) and Short Creek (near Liberty). This 12-mile stretch of the Sangres contains most of the gold-producing districts in the area. Prospectors may want to concentrate on the Precambrian metamorphics and adjacent Paleozoic limestones to begin with, and then extend their search to the younger Pennsylvanian-Permian sediments further up in the section. The many faults and fractures that crisscross the area merit special attention as they are the main controls of ore emplacement in the nearby mining districts. Fragments of "float" from the elusive ledge are occasionally found in the canyons and ravines that drain the western slope of the range. A metal-detector may prove to be useful in the search for gold-bearing float.