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

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Forbes, R. B., and Engels, J. C., 1970, K /Ar age
relations of the Coast Range bathoLith and
related rocks of the Juneau Icefield area,
Alaska: Geological Society of America Bulletin,
v. 81, no. 2, p. 579-584.
Godwin, C. 1., 1975, Imbricate subduction zones and
their relationship with Upper Cretaceous to
Tertiary porphyry deposits in the Canadian
Cordillera: Canadian Journal of Earth Sciences,
v. 12, no. 8, p. 1362-1378.
Hudson, T. L., Smith, J. G., and EUiott, R. L., 1979,
Petrology, composition, and age of intrusive
rocks associated with the Quartz Hill
molybdenite deposit, southeastern Auk&:
Canadian Journal of Earth Sciences, v. 16, no. 9,
p. 1805-1822.
Hunt, S. J., 1983, Preliminary study of a zoned
leucocratic granite body on central Etohn Island,
southeastern Alaska, & Coonrad, W. L., and
1
Elliott, R L., eds., The United States Geological
Survey in Alaska: Accomplishments during
1981: U.S. Geological Survey Circular 868, p.
128-131.
Hutchison, W. W., 1970, Netamorphic framework and
plutonic styles in the Prince Rupert region of the
Central Coast Mountains, British Columbia:
Canadian Journal of Earth Sciences, v. 7, no. 2,
p. 376-405.
I Kindle, E. D., 1953, Dezadeash map-area, Yukon
Territory: Geological Survey of Canada Memoir
268, 68 p, scale 1:253,400.
i
I
Lanphere, M. A., and Eberlein, G. D., 1966, Potassium-
argon ages of magnetite-bearing ultramafic
complexes in southeastern Alaska (abs.3,
Abstracts tor 1965: Geological Society of
America Special Paper 87, p. 94.
Muller, J. E., 1953, Preliminary map, Rluane Lake
(west half), Yukon Territory (descriptive notes):
Geological Survey of Canada Paper 53-20, 9 p.,
scale 1r253,400, 2 sheets.
-1967, Klume Lake map-area, Yukon Territory:
Geological Survey of Canada Memoir 340, 137 p.,
scale 253,400, 2 sheets.
Ovenshine, A. T., and Brew, D. A., 1972, Separation
and history of the Chatham Strait fault,
southeast Alaska, North America: International
Geological Congress, 24th, Montreal, Quebec,
Canada, 1972, Proceedings, sec. 3, p. 245-254.
Plafker, George, Jones, D. L., and Pessagno, E. A,, Jr.,
1977, A Cretaceous accretionary flysch and
melange terrane along the Gulf of Alaska
margin, Blean, K. M., ed., The United States
Geological Survey in &&a: AccompUshments
during 1976: U.S. Geological Survey Circular
751-8, p. B41-R43.
Roddick, J. A., and Hutchison, W. W., 1974, Setting of
the Coast Plutonic Complex, Brl tish Columbia:
Pacific Geology, v. 8, p. 91-108.
Smith, J. G., Stern, T. W., and Arth, J. G., 1979,
Isotopic ages indicate multiple episodes of
plutonism end metamorphism In the Coast
Mountains near Ketchikan, Alaska (abs.1:
Geological Society of America Abstracts with
Programs, v. 11, no. 7, p. 519.
Sonnevil, H. A., 1981, The Chilkat-Prince of Wsles
plutonic province, southeastern Alaska, In
AIbert, N. R. D,, and Budson, Travis, &., The
United States Geological Survey in Alaska:
Accomplishments during 1979: U.S. Geological
Survey Circular 829-8, p. B112-B115.
Souther, J. G., 1971, Geology and ore deposits of
Tulsequah map-area, British Columbia~
Gealogical Survey of Canada Memoir 382, 84 p.
Souther, J. G., Brew, D. A., and Okulitch, A. V., 1979, -
Geology of Iskut Rlver, British Columbia-Alaska,
Geological Atlas, NTS 104, 114: Geological
Survey of Canada Map 1418A, scale 1:1,000,000.
Taylor, R. P., 1967, The zoned ultramafic complexes
of southeastern ALaska, & Wyllie, P. J., ed.,
Ultramafic and related rocks: New York, John
Wiley, p. 97-121.
Wheeler, J. 0,, 1961, Whitehorse mapea, Yukon
Territory: Geological Survey of Canada Memoir
312, 156 p., scale 1:253,400, 2 sheets.
- 1963, Kaskawulsh map-area, Yukon Territory:
Geological Survey of Canada Map 1134-A, scale
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1979, Map showing radiometric ages of mks in
southeastern Alaska: U.S. Geological Survey
Open-Rle Report 79-594, 33 p, scale 1:1,000,000.
Cretaoews pbWc &, Mitkof and Kqmamf
klam%, Pe- quedmqle, mutheastern Alaska
I
By Peter D. Wlrrell I
Reconnabsance geologic mappirig and I
pre.elimtnary petrologic studies of a gmup of similar
granitic bodies in a northwest-trending belt in the
eastern part of the Petemburg quadrangle (area 2, fig.
72) suggest that these bodiea can be divided into
subgroups which are mineralogicaUy similar but
texturally distinct. These rocks are all part of the
Admiralty-ReviUagigedo plutonic belt, whlch ex tends
from Ketchikan to Juneau, outboard of the Coast
plutonic complex; they intrude metamorphic rocks of
the Gravina-Nutzotln belt (Brew and MorreU, 1980).
These granitic bodies occur as stocks of varying
areai extent. They are relatively resistant and form
mountains that rise steeply above the surrounding
country rock. These mountains are heavlly vegetated,
and exposures are poor except on near-vertical
mountain slopes, above tree line, and along the
Intertidal zone. ?he country rocks intruded include
blotite (earnet) schist, semischist, and phylllte. The
intrusions are generally discordant except on central
Mitkof Island, where they appear to be concordant.
Narrow contact aureoles, locally containing mdalusite,
were created by these intrusions.
The stocks of body 1 (fig. 80) on the central
Ljndenberg Peninsula and at Horn Mountain are
crowded plagioclase-porphyritic quartz monzodi6rite
to quartz diorite (see fig. 81 for modal compositions of
aU bodies). The close spacing (crowding) of the
plagioclase phenocrysts (max 12 mm diam) gives the
mafic minerals an interstitial appearance. The
dominant mefic mineral is hornblende; biotite and
epIdote/cIinozolsite are present ln lesser amounts.
Both prlrnary and secondary epidote are present in
these rocks. The quartz and potassium feldspar are