Yolla Bolly Mountain claims (Lonesome Pine; Black Diamond; Black Pearl; Bertha property; Dahrman claim; Emma claim; Emma property; Reliance and Superior claims), Chicago Rock, Coastal Range, Trinity County, California, USAi

Regional Level Types
Yolla Bolly Mountain claims (Lonesome Pine; Black Diamond; Black Pearl; Bertha property; Dahrman claim; Emma claim; Emma property; Reliance and Superior claims)	Group of Claims
Chicago Rock	- not defined -
Coastal Range	Mountain Range
Trinity County	County
California	State
USA	Country

A Mn occurrence/group of claims/prospect located in the SE¼ sec. 32, SW¼ sec. 33 & sec. 34, T27N, R10W, MDM, and in secs. 3 & 4, T26N, R10W, MDM, 2.2 km (7,200 feet) SSW of Chicago Rock (4 miles S of North Yolla Bolly Mountain, on the divide bnetween the South Fork Trinity River and the Middle Fork Eel River, and extending E to the divide between the Middle Fork Eel River and the South Fork Cottonwood Creek, the Emma claim being the westernmost and the Dahrman claim the easternmost.), on Bureau of Land Management/National Forest wiklderness land (Yolla Bolly-Middle Eel Wilderness). MRDS database accuracy for this location is not stated.

The ore body is 3.66 meters thick. Manganiferous chert and rhodochrosite occur in a belt of thin and massive chert 500 feet thick, and at least 1 mile long. The general strike isN70W and the dip is 30NE. The chert is succeeded by Franciscan sandstone and shale on either side. Beds are followed by schist and phyllite about 5000 feet across with a strike to the NE. Many small faults resulted in strongly contorted chert bodies in places. Manganese ore, exposed in 9 or 10 localities, is mostly small ore pockets. Massive white chert lenses are stained. There are 2 extensive occurrences, with a maximum thickness of 12 and 2 feet. The average width of the main zone is 4 feet, but this varies considerably. Relatively little oxide is present. High-grade ore is braunite or hausmannite, and is cut by rhodochrosite veinlets. The remainder of the primary ore is a hydrous Mn silicate, probably neotocite or bementite. Local rocks include rocks of the Franciscan Complex, unit 1 (Coast Ranges).

Analytical data results: Assays reported 24 to 48% Mn, 1 to 2% Fe, and 20 to 46% silica.

Other Databases

Link to USGS MRDS:	10033733

Other Regions, Features and Areas containing this locality

References