New Mexico Geological Society
Fall Field Conference Guidebook - 19
San Juan-San Miguel-La Plata Region, New Mexico and Colorado

John W. Shomaker, ed., 1968, 212 pages.

According to a popular travel guide, "Colorado's San Juan Mountains and the adjacent San Miguel-La Plata Mountain region, with many peaks rising over 14,000 feet, is the closest thing to Switzerland this side of Europe and one of the most beautiful areas of the United States." One might add that the beauty of the region is, to a large degree, dependent upon tremendously interesting and spectacular geological relationships. The New Mexico Geological Society takes pleasure in welcoming you to its Nineteenth Annual Field Conference in this splendid blend of geology and scenery. The first day road log is from Farmington, New Mexico to Cortez, Colorado, via Four Corners Power Plant, La Plata Canyon, La Plata mining area and Mancos. The second day road log is from Cortez, Colorado to Ouray, Colorado via Dolores, Rico, Lizard Head Pass, Telluride, Placerville, Dallas Divide and Ridgeway. The third day road log is from Ouray, Colorado to Farmington, New Mexico via Silverton, Eureka, Durango, and Aztec.

Table of Contents:

Note —Downloads of the papers below are free. Road logs mini-papers, maps, and other sections are only available in print.

1. First day road log from Farmington, New Mexico to Cortez, Colorado, via Four Corners Power Plant, La Plata Canyon, La Plata mining area and Mancos
   — C. M. Molenaar and Larry L. Werts, pp. 11-23.

Papers:

Note — To download papers from this guidebook, you will need a PDF viewer like the free Adobe Acrobat Reader.

2. Summary of geologic data obtained from borehole GB-1, Project Gasbuggy (1.40 MB PDF)
   — James E. Fassett, pp. 24-27.
3. Fluvioglacial features of the Animas River Valley, Colorado and New Mexico (3.75 MB PDF)
   — Charles A. Bandoian, pp. 28-32.
4. Coal-bearing formations in the western part of the San Juan basin of New Mexico (928 KB PDF)
   — Edward C. Beaumont, pp. 33-40.
5. Geology and ore deposits of the La Plata district, Colorado (3.15 MB PDF)
   — Eckel, Edwin B. with sections by Williams, J. S. and Galbraith, F. W. Digest prepared by Trauger, F. D., pp. 41-62.
6. Second day road log from Cortez, Colorado to Ouray, Colorado via Dolores, Rico, Lizard Head Pass, Telluride, Placerville, Dallas Divide and Ridgway
   — J. H. Steward, E. T. McKnight, A. L. Bush, L. R. Litsey, C. T. Sumsion, and C. M. Molenaar, pp. 63-82.
7. Summary of the geology of the Rico Region, Colorado (604 KB PDF)
   — Walden P. Pratt, pp. 83-87.
8. Rico, Colorado: A cenntury of historic adventures in mining (2.00 MB PDF)
   — Charles M. Engel, pp. 88-93.
9. Multiple intrusions in the San Miguel Mountains, Colorado (1.07 MB PDF)
   — Calvin S. Bromfield and Alfred L. Bush, pp. 94-99.
10. Vanadium deposits of the Placerville area, San Miguel County, Colorado (667 KB PDF)
    — R. P. Fischer, pp. 100-103.
11. Third day road log from Ouray, Colorado to Farmington, New Mexico, via Silverton, Eureka, Durango, and Aztec
    — C. M. Molenaar, John W. Shomaker, Larry L Werts, and Jock A. Campbell, pp. 104-129.
12. The Idarado Mine (888 KB PDF)
    — James R. Hillebrand, pp. 130-140.
13. Joint analysis applied to structures of the Silverton volcanic center (1.97 MB PDF)
    — Schwarz, Frederick P., Jr., pp. 141-147.
14. A brief geological history of the Precambrian rocks of the Needle Mountains, southwestern Colorado (423 KB PDF)
    — Fred Barker, pp. 148-149.
15. Character of part of the Hermosa Formation (Pennsylvanian), San Juan Mountains, Colorado (3.84 MB PDF)
    — W. Arch Girdley, pp. 150-158.
16. Pennsylvanian correlations in southwestern Colorado (1.17 MB PDF)
    — Sherman A. Wengerd and Ernest Szabo, pp. 159-164.
17. Photogeologic color analysis an effective supplement to mineral exploration (3.84 MB PDF)
    — Raymond P. Platt, pp. 165-167.
18. Placer gold in southwestern Colorado (2.07 MB PDF)
    — Parker, Ben H., Jr., pp. 168-184.
19. Relationship of uranium in the Rocky Mountains of southwestern Colorado to local and regional metallogenesis (1.43 MB PDF)
    — Roger C. Malan, pp. 185-192.
20. Road log from Albuquerque to Farmington
    — Clay T. Smith, Vincent C. Kelley, Baltz, Elmer H., Jr., and Roy A. Bailey, pp. 193-201.
21. Articles of incorporation, constitution, and by-laws of the New Mexico Geological Society, Inc.
    — New Mexico Geological Society, pp. 202-205.