Ostenaa, D.A., Losh, S.L., and Nelson, A.R., 1981, Evidence for recurrent late Quaternary faulting, Sawatch fault, Upper Arkansas Valley, <strong>Colorado</strong>, in Junge, W.R., ed., <strong>Colorado</strong> tectonics, seismicity and earthquake hazards; Proceedings and field trip guide: <strong>Colorado</strong> <strong>Geologic</strong>al Survey Special Publication 19, p. 27-29. Parker, B.H., 1974, Gold placers <strong>of</strong> <strong>Colorado</strong>: <strong>Colorado</strong> School <strong>of</strong> Mines Quarterly, v. 63, nos. 3 and 4, 262 p. Pearl, R.H., and Barrett, J.K., 1976, Geo<strong>the</strong>rmal resources <strong>of</strong> <strong>the</strong> upper San Luis and Arkansas Valleys, <strong>Colorado</strong>, in Epis, R.C., and Weimer, R.J., eds., Studies in <strong>Colorado</strong> field geology: <strong>Colorado</strong> School <strong>of</strong> Mines Pr<strong>of</strong>essional Contributions 8, p. 439-445. Perry, H.A., 1971, Geology <strong>of</strong> <strong>the</strong> nor<strong>the</strong>rn part <strong>of</strong> <strong>the</strong> Bonanza volcanic field, Saguache <strong>County</strong>, <strong>Colorado</strong>: Golden, Colo., <strong>Colorado</strong> School <strong>of</strong> Mines, M.Sc. <strong>the</strong>sis (T- 1339), 72 p. Powers, W.E., 1935, Physiographic history <strong>of</strong> <strong>the</strong> upper Arkansas River valley and <strong>the</strong> Royal Gorge, <strong>Colorado</strong>: Journal <strong>of</strong> Geology, v. 43, no. 2, p. 184-199. Pulfrey, R.J., 1971, Geology and geochemistry <strong>of</strong> <strong>the</strong> Mount Antero Granite and contiguous units, <strong>Chaffee</strong> <strong>County</strong>, <strong>Colorado</strong>: Oklahoma State University, M.Sc. <strong>the</strong>sis, 84 p. Ramsay, C.R., Stoeser, D.B., and Drysdall, A.R., 1985, Guidelines to classification and nomenclature <strong>of</strong> Arabian felsic plutonic rocks: in Drysdall, A.R., Ramsay, C.R., and Stoeser, D.B., eds., Felsic plutonic rocks and associated mineralization <strong>of</strong> <strong>the</strong> Kingdom <strong>of</strong> Saudi Arabia: Deputy Ministry for Mineral Resources Bulletin 29, pp. 13-20. Reed, J.C., Jr., Bickford, M.E., Premo, W.R., Aleinik<strong>of</strong>f, J.N., and Pallister, J.S., 1987, Evolution <strong>of</strong> <strong>the</strong> early Proterozoic <strong>Colorado</strong> province - Constraints from U-Pb geochronology: Geology, v. 15, no. 9, p. 861-865. Reynolds, D.L., 1956, Calderas and ring complexes: Verhandelingen. Kminkliijke Nederlands Geologisch Mijnbouwkundig Genootschap, v. 16, p. 355-379. Roberts, J.L., 1966, The emplacement <strong>of</strong> <strong>the</strong> main Glen Coe fault-intrusion at Stob Mhic Mhartuin: <strong>Geologic</strong>al Magazine, v. 103, no. 4, p. 299-316. Robinson, C.S., 1961, Pre-Pennsylvanian stratigraphy <strong>of</strong> <strong>the</strong> Monarch district, <strong>Chaffee</strong> 212
<strong>County</strong>, <strong>Colorado</strong>, in Berg, R.R., and Rold, J.W., eds., Symposium on lower and middle Paleozoic rocks <strong>of</strong> <strong>Colorado</strong>: Rocky Mountain Association <strong>of</strong> Geologists, 12 th Field Conference, p. 119-124. Russell, R.T., 1945, The Poncha fluorspar deposits, <strong>Chaffee</strong> <strong>County</strong>, <strong>Colorado</strong>: U.S. <strong>Geologic</strong>al Survey Strategic Mineral Investigations Preliminary Report 3-210, 12 p. Russell, R.T., 1950, The geology <strong>of</strong> <strong>the</strong> Poncha fluorspar district, <strong>Chaffee</strong> <strong>County</strong>, <strong>Colorado</strong>: Cincinnati, Ohio, University <strong>of</strong> Cincinnati, Ph.D. <strong>the</strong>sis, 70 p. Scott, G.R., 1975, Reconnaissance geologic map <strong>of</strong> <strong>the</strong> Buena Vista quadrangle, <strong>Chaffee</strong> and Park Counties, <strong>Colorado</strong>: U.S. <strong>Geologic</strong> Survey Miscellaneous Field Studies <strong>Map</strong> MF-657, scale 1:62,500. Scott, G.R., and Taylor, R.B., 1975, Post-Paleocene Tertiary rocks and Quaternary volcanic ash <strong>of</strong> <strong>the</strong> Wet Mountain Valley, <strong>Colorado</strong>: U.S. <strong>Geologic</strong>al Survey Pr<strong>of</strong>essional Paper 868, p. 1-15. Scott, G.R., Van Alstine, R.E., and Sharp, W.N., 1975, <strong>Geologic</strong> map <strong>of</strong> <strong>the</strong> Poncha Springs quadrangle, <strong>Chaffee</strong> <strong>County</strong>, <strong>Colorado</strong>: U.S. <strong>Geologic</strong>al Survey Miscellaneous Field Studies <strong>Map</strong> MF-658, scale 1:62,500. Scott, G.R., Taylor, R.B., Epis, R.C., and Wobus, R.A., 1978, <strong>Geologic</strong> map <strong>of</strong> <strong>the</strong> Pueblo 1° x 2° quadrangle, south-central <strong>Colorado</strong>: U.S. <strong>Geologic</strong>al Survey Miscellaneous Investigations Series, scale 1:250,000. Shannon, J.R., 1981, Unpublished data. Shannon, J.R., 1984, Unpublished data. Shannon, J.R., 1986, The Mount Antero and California intrusions, <strong>Chaffee</strong> <strong>County</strong>, <strong>Colorado</strong>; Evidence for early evolution <strong>of</strong> pegmatitic fluids: <strong>Colorado</strong> Pegmatite Symposium, Friends <strong>of</strong> Mineralogy, p. 84-86 Shannon, J.R., 1988, Geology <strong>of</strong> <strong>the</strong> Mount Aetna cauldron complex, Sawatch Range, <strong>Colorado</strong>: Golden, Colo.,<strong>Colorado</strong> School <strong>of</strong> Mines, Ph.D. <strong>the</strong>sis (T-3521), 434 p. Shannon, J.R., and Epis, R.C., 1987, Deeply-eroded, ring zone structures <strong>of</strong> <strong>the</strong> Mount Aetna cauldron, <strong>Colorado</strong> [abstr.]; Hawaii Symposium on How Volcanoes Work, Hilo, Hawaii, p.231. Shannon, J.R., Epis, R.C., Naeser, C.W., and Obradovich, J.D., 1987a, Correlation <strong>of</strong> 213
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OPEN-FILE REPORT 06-10 Geologic Map
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TABLE OF CONTENTS Introduction…
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mylonitic, augen textures………
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INTRODUCTION LOCATION AND ACCESS Th
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SAWATCH RANGE RIFT-SHOULDER UPLIFT
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of the South Arkansas River (subseq
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EXPLANATION Rio Grande Rift Neogene
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in descriptions of the geologic uni
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During the Early and Middle Paleozo
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Mountains, and White River uplifts
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field are the largest remnants of t
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Figure 5. Detailed geologic-structu
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with the Colorado mineral belt (Boo
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Shannon, 2005). Widmann and others
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the Upper Arkansas graben (fig. 5)
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15-minute quadrangle, which is adja
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etween the northern and southern se
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on U.S. Forest Service color aerial
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We use fractional map units on the
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Qpt Pinedale till, undivided (late
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weathered, but Mount Princeton quar
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stratified, matrix-supported, bould
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as rockfalls, rock avalanches, rock
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stream-channel deposits of all pere
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Figure 10. View west up South Arkan
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Figure 11. View west up South Arkan
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valley near the eastern map boundar
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lithologies are variable and depend
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Arkansas River in parts of Redman C
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angular to subangular. Deposits gen
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elations, age constraints from foss
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elated to the inferred Squaw Creek
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Figure 14. Crude bedding in coarse
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microcline, and muscovite. The latt
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Volcanic Ash Figure 17. View of eas
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Figure 18. Close-up view of intense
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The western zone of brecciated Pale
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Tr Rhyolite dikes (early to late Ol
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as the overall N47°E trend of the
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One age determination on the rhyoli
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northwest-trending fault. Thus, fie
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on the North Fork leucogranite intr
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A small 400 by 400 foot body of Nor
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N12°E, 62°NW (about 6,000 ft sout
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The age of the quartz latite porphy
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Tma Mount Aetna quartz monzonite po
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of the Maysville quadrangle and the
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Mount Aetna ring dikes (Tma), one i
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the margins of the pluton, includin
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Shannon (1988). The average of seve
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indicating a granite b composition
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analysis by Crawford (1913), two an
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locally tanish to pinkish gray. It
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quadrangle (tables 1 and 3) were fr
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slices of Paleozoic sedimentary roc
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south-southwest of Maysville is a 9
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There is one additional Paleozoic s
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near the southwest margin of the qu
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eastern contact of the diorite intr
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endoskarn zones. The two widely sep
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Xhig) along the southeastern contac
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Xgd Granodiorite (Early Proterozoic
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Hybrid granodiorite is locally deve
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Xcs Calc-silicate gneiss (Early Pro
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Many of the calc-silicate gneiss zo
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typically expressed by intermittent
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The field relations and characteris
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the north side of all three segment
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eplaced by muscovite. The western m
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sillimanite-quartz-muscovite that a
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sillimanite gneiss (Xmsg) and the m
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Figure 35. Outcrop of Proterozoic h
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samples) indicates they are compose
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Xal Lineated amphibolite (Early Pro
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of the Proterozoic metamorphic rock
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that the present structural configu
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elated to rotation of domain blocks
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sometimes terminate at a cross stru
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limestone that is exposed in a wind
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quadrangle are intimately associate
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- Page 165 and 166: that truncates the Upper Arkansas g
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- Page 201 and 202: WATER RESOURCES Water resources on
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- Page 211: Litsey, L.R., 1958, Stratigraphy an
- Page 215 and 216: Stark, J.T., and Barnes, F.F., 1935
- Page 217 and 218: Tweto, O., 1987, Rock units of the
- Page 219 and 220: quadrangle, Colorado: U.S. Geologic
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- Page 223 and 224: 336A 396189 4274961 Prospect Xgdf B
- Page 225: 854 391849 4268852 42 Adit; Geochem