n Alas - Alaska Division of Geological & Geophysical Surveys - State ...

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Berg, R. C., Jones, D. L., and Richter, D. H., 1972,
Gravina-Nitzotin belt-teetonic significance of
en upper Mesozoic sedimentary and volcanic se-
quence in southern and southeastern Alaska, &
Geological Survey research 1972: U.S. Geologi-
cal Survey Professional Paper 800-D, p. Dl-D24.
Bayle, R. W., 1979, The geochemistry of gold and its
deposits: Geological Survey of Canada Bulletin
284, 585 p.
Efraoks, A. W., 1912, Gold deposits near Valdez, &
Mineral resources of Alaska: Report on progress
of investigations in 1911: U.S. Geological Survey
Bulletin 520, p. 108-130.
Cobb, E. H., and Matson, N. A., compilers, 1972,
Metallic mineral resources map of the Valdez
quadrangle, Alaska: U.S. Geological Survey Mis-
cellaneous Field Studies Map RIP-438, scale
1:250,000.
Henley, R. W., Norris, R. J., and Peterson, C. J., 1976,
Multistage ore genesis In the New Zealand geo-
syncline-a history of post-metamorphic Me
emplacement: Minerallurn Deposits, v. 11, no. 1,
p. 180-196.
Hudson, Travis, Plafker, George, and Peterman, Z. E.,
1979, Paleogene anatexis along the GuLf of
Alaska margin: Geology, v. 7, no. 12, p. 573-577.
Johnson, 8. L., 1915, The gold and copper deposits of
the Port Valdez district, Mineral resources of
Alaska: Report on progress of investigations in
1914: U.S. Geological Survey Bulletin 622, p.
140-188.
MacKevett, E. M., Jr., and Plaker, George, 1974, The
Border Ranges fault in south-central Alaska:
U.S. Geological Survey Journal of Research, v. 2,
no.3,p.323-329.
Mitchell, P. A., 1879, Geology of the Hope-Sunrise
(gold) rnidng district, north-central Renal PenIn-
sula, Alaska: Stanford, Callf., Stanford Univer-
sity, M. Sc. thesis, 123 p.
Mitchell, P. A, Siberman, M. L., and OINeU, J. R.,
1981, Genesis of gold vein mineralization in an
Upper Cretaceous turbidite sequence,
Hope-Sunrtse district, southern Alaska: U.S.
Geological Survey Open-File Report 81-1 03, 18
P
Plafker, George, Jones, D. L., and Pesagno, E. A., Jr.,
1977, A Cretaceous accretionary flysch and
melange terrane along the Gulf of m k a
margin, & Blean, K. M., ed., The United States
Geolqicd Survey in Alaska: Accomplishments
during 1976: U.S. Geologicld Survey Circular
751-B, p. B4L-B43.
Robin, P. Y. P., 1979, Theory of metamorphic segrega-
tion and related processes: Geochimica et Cos-
mochirnica Acta, v. 43, no. 10, p. 1587-1600.
Roedder, Edwin, 1967, Metastable superheated ice in
liquid-wMer inclusions under high negative pres-
sure: Science, v. 155, no. 3768, p. 1413-1416.
-1972, Composition of fluid inclusions, chap. JJ 9
Fleischer, Michael, ed., Data of geochemistry
(6th ed.): U.S. Geological Survey Professional
Paper 440-53, p. 55155164.
-1979, Pluid inclusions as samples of ore fluids, 5
Barnes, B. L., ed., Geochemistry of hydrothermal
ore deposits (2d ed.): New York, John Wiley, p.
684-780.
Silberman, M. L., Mitchell, P. A,, end OtNeil, R., Jr.,
1981, lsotoplc data bearing on the origin and age
of the epithermnl lode gold deposits in the Hope-
Sunrise mining district, northern Ken& Penh-
sula, Alaska, Albert, N. R. D., and Hudson,
Travfs, eds., The United States Geological Survey
in Alaska: Accomplishments during 1979: U.S.
Geological Survey Circuiar 823-B, p. B81-B84.
Winkler, G. R., Sllberman, M. L., Grantz, Arthur,
Miller, R. J., and MacKevett, E. M., Jr., 1980,
Geologic map and summary geochronokogy of the
Valdez quadrangle, southern Alaska: U.S. Geo-
logical Survey Open-Pile Report 80-892-A, scale
1:250,000, 2 sheets.
A preliminary gewhemieal interpretation of the
Chugach Wildemes, eouthern Alaska
A geochemical survey is currently being con-
ducted in the Chugach Wilderness, southern Alaska
(area 0, fig. 441, as part of the U.S. Geological
Survey-Pore~t Service's mineral resource appraisal
program. Most of the Chugach Wilderness is contained
within the Seward and Cordova 1:250,000-scale quad-
rangles (fig. 57). These two quadrangles were pre-
viously sampled on a reco~aissance basis by the h s
Marnos National Laboratory (LANL) for the U.S.
Department of Energy's National Uranium Resource
Evaluation (NURE) program. Neutron-activetion anal-
ysis was used to determine the concentrations of 32
elements (AL, Au, Ba, Ca, Ce, CI, Co, Cr, Cs, Dy, Eu,
Pel Hf, K, La, Lu, Mg, Mn, Na, Rb, Sb, Sc, Srn, Sr, Ta,
Tb, Th, Ti, V, Yo, U, Zn) and X-ray fluorescence spec-
troscopy to determine the concentrations of 9 other
elements (Ag, Bi, Cd, Cu, Nb, Ni, Pb, Sn, W).
Geochemical interpretations of these LANL stream-
sediment data bases for the Seward and Cordova quad-
rangles (u.S. Department of Energy, 1981, 1982) are
being used to supplement the current study in the
Chugach Wilderness. Statistical interpretation of the
LANL data is aiding in the recognition of target areas,
justifying more detailed fieldwork.
An R-mode factor analysis with varirnax was run
on analytical data from the 498 streamsediment sam-
ples collected by LANL from the Cordova quadran-
gle. AppIying the principles of matrix algebra, R-
mode factor analysis is used to reduce an extensive
data matrix into a much smaller factor matrix of
inteccorrebted variables (see Joreskog and others,
1976); '%acirnaxU refers to orthogonal rotation of the
factor axes to obtain a better fit to the variable (ele-
ment) clusters. R-mde factor analyda was used to
find the groupings of associated elements that are
characteristic of various localities within the quadran-
gle. A five-factor model was used that explained 68
percent of the overall data variance. Table 18 Usts
these factors and the approximate locetions of the
sites with highest factor scores.
The suite of rareearth elements constitutlrtg
factor I (table 18) appears to be characteristic of the
phyUite and schist (Winkler and Plafker, 1981) that
crop out in the northeast corner of the quadrangle. In