Incas Manganese Prospect, Bristol Mountains, San Bernardino County, California

Transcription

1 Incas Manganese Prospect, 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 9N 8E Sec. 09 SBM MRDS This property was formerly known as the Southern Pacific Company Prospect (MRDS). The Southern Pacific geologic map for T.8N, R.09-10E shows the property as the Incas Mine. The MRSD database lists this as an Unnamed Prospect. The mine is in the northwestern Bristol Mountains, 4.3 miles northeast of Bristol Dry Lake. See Figures 1 and 2. The Incas Manganese Mine is in SE1/4NE1/4 of Section 9, T.9N., R.8E (Coonrad and Dahehy. 1958, p. 4). OWNERSHIP AND HISTORY None described. GEOLOGY The Southern Pacific report for T.09N, R.07-08E gave this description and assessment of the Incas Mine This prospect was examined and reported upon by Smith and Price (1919) and Smith and Magill (1920). It apparently has not been worked significantly since then and appears as described in those reports. the occurrence is primarily a small manganese-stained quartz vein with the adjacent quartz monzonite also having some stain. Smith and Price (1919) give an assay of the two-foot vein on the foot wall and also an assay of a sample taken through four feet of the mineralized hanging wall (gold, trace; silver, 0.12 oz/ton and 0.36 oz/ton, respectively). Smith and Magill (1920) report an assay of the best manganese ore taken from a few hundred pounds piled up on the dump" as: Gold oz/ton Silver oz/ton Manganese percent The total amount of mineralization is small. Because the precious metal content is low and the silica content of the manganese high, this deposit is noneconomic (Coonrad and Dahehy. 1958, p. 4). Kumpfer and Bassett (1962) mapped the area of the Incas Manganese Mine as Pre-Tertiary undifferentiated plutonic and metamorphic rocks (pm). See Figure 3. 1

2 Dibblee (2008b) mapped the area as Cretaceous Granite (gr). See Figure 4. Southern Pacific (1959) mapped the area as Jurassic-Cretaceous Quartz Monzonite (JKqm). See Figure 5. A regional geologic mosaic of the Bristol and Old Dad Mountains is at: A regional stratigraphic compilation for this mosaic is at: tains_san_bernardino_county_california_text REFERENCES Coonrad, W.L. and E.A. Dahehy. 1958, Geology and Mineral Resources of Township 9 North, Ranges 7 and 8 East, San Bernardino Base and Meridian, San Bernardino County California, Southern Pacific Company, unpublished report. Dibblee, Thomas W., Jr., 2008b, Geologic Map of the Broadwell Lake 15 Minute Quadrangle, San Bernardino County, California, Dibblee Foundation Map #DF-395. Kumpfer, Donald H. and Allen M. Bassett, 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. MRDS, 2011, Mineral Resources Data System, U.S. Geological Survey, Smith, A.M., and Chas. Magill, 1920, Mineral report on NE1/4 of Section 9, Twp. 9N., Rge. 8E., SBM: So. Pac. Co. files, S.F., 12/12/20 (unpublished). Smith, A.M., and Price, J.H., 1919, Mineral report on NE1/4 of Sec. 9, Twp. 9N. 1 Rge. 8E., SBM: So. Pac. Co.files, S.F. 11/4/ and 7/19 (unpublished). 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. 144 Southern Pacific, 1964, Geology and Mineral Resources of T.09N-R.07-08E, SBM with map. MAPS 2

3 Figure 1. Regional topographic map of the Incas Manganese Mine and surrounding area. 3

4 Figure 2. Topographic map of the Incas Manganese Mine and surrounding area. 4

5 Figure 3. Geologic map of the Incas Manganese Mine and surrounding area. Adapted from Kumpfer and Bassett,

6 Figure 4. Geologic map of the Incas Manganese Mine and surrounding area. Adapted from Dibblee (2008b)

7 Figure 5. Geologic map of the Incas Manganese Mine and surrounding area. Adapted from Southern Pacific,