8N 10E Sec. 08 SBM MRDS, Wright et al, 1953

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1 Ribbon Rock Onyx Mine, Bristol Mountains, San Bernardino County, California Gregg Wilkerson 2017 Acknowledgement and Disclaimer The information in this paper is taken largely from published sources. I have reproduced this material and present it pretty much as I found it, not trying to harmonize discrepancies in mine descriptions. I have changed verb tenses for readability and have used some paraphrase. Authors of the original information are indicated at the end of each paragraph. Paragraphs without a citation are my own material. LOCATION 8N 10E Sec. 08 SBM MRDS, Wright et al, 1953 The Ribbon Rock Onyx Mine is in the northern Bristol Mountains, Section 8, T.9N., R.10E., SBBM, San Bernardino County (Southern Pacific, 1954, p. 189). This location disagrees with the MRSD location. The mine in Section 8 of T.8N, R.9E is the Reinerth Prospect in the MRSD database. A description of this mine is made in a companion article. The Southern Pacific bi-township map of the Ribbon Mine area (1959) shows it to be at the MRSD location. The MRDS location is 8.0 miles northeast of Ash Hill. OWNERSHIP AND HISTORY In in 1953 the mine was owned by Ralph W. Ross, 710½ Park Ave., South Pasadena, California (Wright and others, 1953, p. 141). GEOLOGY The Southern Pacific report (1954) for T.8N, R,09-10E, SBM describes the Ribbon Rock mine: The mine is an open pit. It has two veins of banded silver onyx (travertine) strike N80 W, dip 80 S in intrusive andesite and latite porphyry (Southern Pacific, 1954, p. 189). Lauren Wright and others (1953) described the mine this way: The deposit has red and brown, banded marble onyx. It was largely undeveloped in 1953 when small amounts of material were removed for testing. The mine was idle in 1953 (Wright and others, 1953, Table, p. 141). In the book Gem Trails of Southern California, the Ribbon Rock deposit is called the Bristol Mountains Onyx Deposit. The onyx deposit is described thus: At road's end, you will be at the center of the collecting site. It is easy to spot where the earlier miners had quarried the beautiful onyx, and it is there where you should begin your search. The material of primary inter est here is called Strawberry Onyx, due to its reddish-pink color. The hues are often vivid 1

2 and the swirls and bands pronounced. This, in fact, is some of the best onyx to originate from the Mojave Desert. The only reason the mine couldn't make a profit was due to the expense of getting it back to "civilization." (Mitchel, 1998, p. 74). There is lots of already broken up material lying throughout the mine area, but, if you want to go after the deposit itself, you will need heavy sledge hammers, gads, chisels, pry bars, gloves, goggles and lots of energy. The onyx is tough, and removing sizable pieces involves lots of work. This is one of those locations, however, where that work could really pay dividends (Mitchel, 1998, p. 74). To the west is a little valley. Throughout that valley are lots of addi tional onyx outcrops which are generally easy to spot due to their dark appearance. Any of them can provide additional potential for more good specimens, including a nice brown, tan and beige variety. In addition, there is lots of jasper, especially on and around the little hill just west of the quarry (Mitchel, 1998, p. 75). Kumpfer and Bassett (1962) mapped the area of the Ribbon Rock Onyx Mine as Quaternary-Tertiary undifferentiated volcanic rocks (QTuv). Southern Pacific (1959) mapped the area as at a contact between Pliocene Tuff Breccia in part pumiceous and perlitic (Tltubi) and Pliocene Pumiceous tuff and tuff breccia undifferentiated (Tutu). REFERENCES Kumpfer, Donald H. and Allen M. Basset, 1962, Reconnaissance Map of Part of the Mojave Desert, California, in A Geologic Reconnaissance of the Southeastern Mojave Desert, California Division of Mines and Geology Special Report 83 and U.S. Geological Survey Mineral Investigations Field Studies Map MF-205 scale 1:125K. Michell, James R., 1996, Bristol Mountains Onyx, Gem Trails of Southern California, Gem Guides Book Company, 176 p., pp MRDS, 2011, Mineral Resources Data System, U.S. Geological Survey, Southern Pacific Company, 1964, Minerals for Industry, Volume III Southern California, California Division of Mines and Geology, Special Report 95, 242 pages plus maps. The data in this report is based on geologic maps Southern Pacific produced pre-1964 covering two townships each. These maps create a mosaic of township geologic maps throughout much of the Mojave Desert. These have been scanned and rectified and are on file with the Bureau of Land Management, Riverside, California. See p Southern Pacific, 1959, Geology and Mineral Resources of T.08N-R.09-10E, SBM with map. Mapping by Raymond T. Laird, Wright, Lauren A., Richard M. Stewart, Thomas E. Gay, Jr., and George C. Hazenbush, 1953, Mines and Mineral Deposits of San Bernardino County, California, California Journal of Mines and Geology, v. 49, n. 1 and 2, 192 pages plus maps. See p

3 MAPS Figure 1. Regional topographic map of the Ribbon Rock Onyx mine and surrounding area. 3

4 Figure 2. Topographic map of the Ribbon Rock Onyx mine and surrounding area. 4

5 Figure 3. Geologic map of the Ribbon Rock Onyx mine and surrounding area. Adapted from Kumpfer and Bassett,

6 . Figure 4. Geology of the Ribbon Rock Onyx Mine. Adapted from Southern Pacific Co.,