n Alas - Alaska Division of Geological & Geophysical Surveys - State ...
n Alas - Alaska Division of Geological & Geophysical Surveys - State ... n Alas - Alaska Division of Geological & Geophysical Surveys - State ...
F5gme S%.--SKetch map of M Wt Hayes quadrangle, showing selected geochernically anomalous areas (stIpLtng) north of Denalt fault. In the vicinity of the Macomb Plateau, Berry Creek, and Knob Ridge in the eastern part of the quad- rangle (ti . 581, anomalously hi h tin (greater than 2,000 ppm\ tungsten (10,000 pprn?, and antimony (700 pprn) values in heavy-mineral-concentrate samples suggest greisen occurrences in this terrane. The highest tin values detected in minus-80-mesh streem- sediment (200-500 ppm) are in two samples collected from Berry Creek. These samples also contain large amounts of silver (1-7 pprn), lead (150 ppm), zinc (150- 300 ppm), and tungsten (1,000 ppm). Tin values of greater than 2,000 pprn occur tn the associated heavy- mineral-concentrate samples tageU~er with anomalous amounts of silver (20-100 pprn), copper (1,000-1,500 ppm), lead (1,000-2,000 pprn), and zinc (1,000-1,500 ppm). Minerdogie examination of these heavy- mineral-concentrate samples confirmed the presence of cwiterite, scheelite, and fluorite, all common minerals in greisen occurrences, together with gold, chalcopyrite, and galena. REFERENCES CITED Cobb, E. H., compiler, 1972, Metallic mineral resources map of the Mount Hayes quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-414, scale 1:250,000. Evenson, B. B., Stephens, CS. C., Weber, F. R., King, H. D., and Detra, D. E., 1983, Mineral exploration and reconnaissance bedrock mapping wing active alpine glaciers, Mount Hayes and Healy quadran- gles, southern Alaska, Coonrad, W. L., and EUiatt, R. L., eds., The United States Geological Survey in Alaska: Accomplishments during 1981: U.S. Geological Survey Circuler 888, p. 94- 95. O'Leary, R. M., Risoli, D. A., Curtin, G. C., Tripp, R. B., McDougal, C. M., and Huston, D. L., 1982, Pinal analytical rerrults of stream sediment, glacial debris and non-magnetic heavy-mineral concentrate samples from the Mount Hayes quadrangle, Alaska: U.S. Geological Survey Open-File Report 82-325, 128 p.
Mineral qItWation end r ~ k t k W e bed1'6~k mapping using active alpine ghciers, Mount Bayes and Reaty quadraqgles, southern Alaska By edward B. E v m Gearge C. Stephem, P. R Nehet, Barley D. ging, and David 8 Detm We conducted a detailed sampling program of the supraglacial debris bad of Susitna Glacier, Mount Hayes B-6 and C-6 and Healy B-1 and G1 quadrangles (area 8, fig. 44; fig.' 591, during August 1B8l. 'T'91i.s program involved the refinement of an application of techniques initiated during the Pident Glecler Project (Evenson and others, 1982). The principal project objective remained the same-the rapid and accurate evaluation of mineral potential, particularly metallic- mineral resources. Situated in the same alpine massif and sharing iee divides with the Trident Gbcier system (192-km catchrynt area), the Susitna Glacier system drab a 288-km catchment area; it has 69 distinct medial moraines. Methodologies employed for delineation of these medial moraines and estabkhrnent of their points of origin were the same as those utilized in the Trident Glaeier Project. Modification and refinement of tech- niques, based on the results and Interpretations from Trident Ohcier, consisted primarily of revisions of sampling schemes to yield a more time efficient field program with minimal loss of interpretative accura- cy. This year, pebble, cobble, end boulder fractions were identified, examined, and quantified in the field, whereas in 1080 pebbles were collected for subsequent analysis. Representative samples of each rock type and sandsize and finer (silt and clay size) fractions were again collected as previously described (Evenson and others, 1982). lhese modifications realized a 50- percent reduction in the time required for field exami- nation of the supraglacial debris load. The samples end data collected on Susttna Glacier are presently being analyeed and interpreted. Assessment and interpretation of lithologic data (pebble, cobble, and boulder suites) collected during the Trident Glacier investigation concerndr (1) Litho- logic composition, (2) structural interpretation, and (3) identification of visEble mineralization. Lithologic differentiation was based on field and laboratory iden- tification of the cobble and boulder fraction of the supraglacial debris load. Coupled with determination Plgrae 59.-4ampletraverse routes on Mdent and Susitna Glecie~s, Mount Heyes quadrangle, Aladca. 84
- Page 51 and 52: various Utholagic units present Thu
- Page 53 and 54: fault, and Its depositional basemen
- Page 55 and 56: suggested by coplanar foUaticm and
- Page 57 and 58: 1 slgnlficarrtly more umnlum (73&1,
- Page 59 and 60: ecrSigtallized catadastic matrix of
- Page 61 and 62: analyzed to determine whether Immob
- Page 63 and 64: are tgplcd of both ocean-floor basa
- Page 65 and 66: & Fclsic in~rutirt rucks 0 Eio~ite
- Page 67 and 68: are Lrdlcated by coexisting @&ite+q
- Page 69 and 70: (Mg3.09 pe2+ 0.69 pe 0.~1~0.01~~0.9
- Page 71 and 72: westward into a narrow band that ex
- Page 73 and 74: EXF'lANATIOW 66600' Contan-Apprnimn
- Page 75 and 76: ! few fold closures are preserved.
- Page 77 and 78: even thickness and conform to irreg
- Page 79 and 80: (Alnus ap.), heaths (Ericaceae, + E
- Page 81 and 82: terrane extends at least 300 krn to
- Page 83 and 84: Table 19.--6tneral petrography of M
- Page 85 and 86: were measured on 8 12-in. mass spec
- Page 87 and 88: Thin lenses of cabonate packtone to
- Page 89 and 90: The cantwell(?) Pormation south of
- Page 91 and 92: in the 18 lava flows b thermoremane
- Page 93 and 94: Upper Cretaceous shale in contact w
- Page 95 and 96: Gran tz, Arthur, 1960, Generalized
- Page 97 and 98: at 15 to 20 percent. Primary Inolus
- Page 99 and 100: addition, this factor generally def
- Page 101: Joreskog, K. G., Klovan, J. E., and
- Page 105 and 106: 1 "~_liO-/ 200 1000 B roo C E % A B
- Page 107 and 108: Smaller placer mines ere active on
- Page 109 and 110: Figme 62.-Plant fassils from the co
- Page 111 and 112: Hallam, Anthony, 1975, Alfred Wegen
- Page 113 and 114: u ALASKA Figure 65.--Sketch map of
- Page 115 and 116: F ' i a?.-Intertidal bluffs compose
- Page 117 and 118: C-s - - Figure 70.-Products of eros
- Page 119 and 120: curve is based indicates that 6.1 c
- Page 121 and 122: sampled is related to widespread ma
- Page 123 and 124: marble is alsa locally present In t
- Page 125 and 126: Bedding in the conglomerate ranges
- Page 127 and 128: 1 purpose of this study wes to dete
- Page 129 and 130: The secona k~~-~ri?tation mmes that
- Page 131 and 132: epizonb'l granitic Miss, mixed with
- Page 133 and 134: 40 40 Forbes, R. B., and Engels, J.
- Page 135 and 136: foliated and inequigranular end con
- Page 137 and 138: I I thy euheclra. Sphene anhedra an
- Page 139 and 140: Quartz Alkali feldspar Plagioclase
- Page 141 and 142: F'@m 85.--Sketch map of Juneau area
- Page 143 and 144: HoUister, L. 8, 1966, Garnet zoning
- Page 145 and 146: ! ~ bI8oO, (IN PERMIL) ~lqp~e 87.-8
- Page 147 and 148: Figure 90.-Offshore ereas discussed
- Page 149 and 150: Preliminerg analpsis of miemfauna f
- Page 151 and 152: Survey tn Alaekai AccompUshments hh
F5gme S%.--SKetch map <strong>of</strong> M Wt Hayes quadrangle, showing selected geochernically anomalous areas<br />
(stIpLtng) north <strong>of</strong> Denalt fault.<br />
In the vicinity <strong>of</strong> the Macomb Plateau, Berry<br />
Creek, and Knob Ridge in the eastern part <strong>of</strong> the quad-<br />
rangle (ti . 581, anomalously hi h tin (greater than<br />
2,000 ppm\ tungsten (10,000 pprn?, and antimony (700<br />
pprn) values in heavy-mineral-concentrate samples<br />
suggest greisen occurrences in this terrane. The<br />
highest tin values detected in minus-80-mesh streem-<br />
sediment (200-500 ppm) are in two samples collected<br />
from Berry Creek. These samples also contain large<br />
amounts <strong>of</strong> silver (1-7 pprn), lead (150 ppm), zinc (150-<br />
300 ppm), and tungsten (1,000 ppm). Tin values <strong>of</strong><br />
greater than 2,000 pprn occur tn the associated heavy-<br />
mineral-concentrate samples tageU~er with anomalous<br />
amounts <strong>of</strong> silver (20-100 pprn), copper (1,000-1,500<br />
ppm), lead (1,000-2,000 pprn), and zinc (1,000-1,500<br />
ppm). Minerdogie examination <strong>of</strong> these heavy-<br />
mineral-concentrate samples confirmed the presence<br />
<strong>of</strong> cwiterite, scheelite, and fluorite, all common<br />
minerals in greisen occurrences, together with gold,<br />
chalcopyrite, and galena.<br />
REFERENCES CITED<br />
Cobb, E. H., compiler, 1972, Metallic mineral<br />
resources map <strong>of</strong> the Mount Hayes quadrangle,<br />
<strong>Alas</strong>ka: U.S. <strong>Geological</strong> Survey Miscellaneous<br />
Field Studies Map MF-414, scale 1:250,000.<br />
Evenson, B. B., Stephens, CS. C., Weber, F. R., King, H.<br />
D., and Detra, D. E., 1983, Mineral exploration<br />
and reconnaissance bedrock mapping wing active<br />
alpine glaciers, Mount Hayes and Healy quadran-<br />
gles, southern <strong>Alas</strong>ka, Coonrad, W. L., and<br />
EUiatt, R. L., eds., The United <strong>State</strong>s <strong>Geological</strong><br />
Survey in <strong>Alas</strong>ka: Accomplishments during<br />
1981: U.S. <strong>Geological</strong> Survey Circuler 888, p. 94-<br />
95.<br />
O'Leary, R. M., Risoli, D. A., Curtin, G. C., Tripp, R.<br />
B., McDougal, C. M., and Huston, D. L., 1982,<br />
Pinal analytical rerrults <strong>of</strong> stream sediment,<br />
glacial debris and non-magnetic heavy-mineral<br />
concentrate samples from the Mount Hayes<br />
quadrangle, <strong>Alas</strong>ka: U.S. <strong>Geological</strong> Survey<br />
Open-File Report 82-325, 128 p.
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