The Alaska Mineral Resource Assessment Program: Guide to information about the geology and mineral resources of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska

Abstract

I. T i t l e. 11. Series: U n i t e d States. G e o l o g i c a l Survey. C i r c u l a r 855. QE75.CS no. 855 622 s 82-600083 CTN24. A41 t557.98'21 AACR2 Free on application to Branch of Distribution, U.

Geologic map of southeastern Alaska

“…Based on regional stratigraphic relations, Plafker and Hudson ( I 980) argue that the strata near Haines are probably not correlative with the other volcanic rocks in this unit. Consists of: unnamed rhyolite on Annette lsland and the Puppets Formation (rhyolite) on Gravina lsland (Berg, 1982); the Chapin Peak Formation (basalt) on Gravina lsland (Berg and others, 1978); the Keku Volcanics (rhyolite and subordinate basalt) and the Hound lsland Volcanics (basalt and andesite) in Keku Strait (Muffler, 1967;Brew and others, 1984); and unnamed basalt near Haines (Plafker and Hudson, 1980;Redman and others, 1984;Robertson, 1959 (Berg and others, 1978); the Nehenta Formation on Gravina lsland (Berg and others, 1978); unnamed strata interpreted to occur as blocks in a disrupted sedimentary unit (KJsd) on Kupreanof and Zarembo lslands (D.A. Brew, in U, S. Geological Survey, 1982;Brew and others, 1984;Berg and Grybeck, 1980); and the part of the Hyd Formation on Admiralty lsland that has been reliably separated from the Cannery Formation (Ps) (Lathram and others, 1965 (Berg, 1982), the Cornwallis Limestone and Hamilton lsland Limestone on northern Kuiu and Kuprcanof lslands (Muffler, 1967;Brew and others, 19841, and the Whitestripe Marble on Chichagof lsland (Loney and others, 1975;Johnson and Karl, I 982).…”

Geologic map of southeastern Alaska

“…Some stippled intrusive rocks contain unmapped inclusions of country rock and are also intruded by younger igneous rocks. (Loney and others, 1975) and unnamed basaltic to rhyolitic rocks on islands west of Prince of Wales Island (Eberlein and others, 1983), on Revillagigedo Island and mainland to east (Berg andothers, 1978, 1988), near Alaska-British Columbia border east of Wrangell Island , and on Zarembo, Kuiu, and Kupreanof Islands (Brew and others, 1984). Rocks of Holocene age were recognized east of Wrangell Island (Elliott and others, 1981) and on Kruzof Island (Loney and others, 1975), and basaltic rocks of Holocene and (or) Pleistocene age are found on southern Kupreanof Island (Brew andothers, 1984, 1985) (Plafker and Addicott, 1976;George Plafker, written commun., 1984) Tv Volcanic rocks (Tertiary)-Oligocene and Eocene basalt and andesite (Admiralty Island Volcanics) on Admiralty Island (Lathram and others, 1965); unnamed Oligocene basaltic rocks on islands in ley Strait (Hudson and others, 1982); basaltic rocks (Cenotaph Volcanics) of Miocene and Oligocene age along coast northwest of Cross Sound (Brew and others, 1978) Ford, 1985); and andesitic to rhyolitic tuff and breccia (Sloko Group) of Eocene age northeast of Juneau (Brew and Ford, 1985;Souther, 1971 ).…”

“…Plafker and others (1976) and Jones and others (1977) also suggest that the Whitestripe Marble is not correlative with other carbonate rocks included in this unit. Unit consists of ( 1) limestone and marble (parts of the Hyd Group) on Annette and Gravina Islands (Berg and others, 1978, 19 88;Berg, 1982;Gehrels and others, 1987); (2) the Cornwallis Limestone and Hamilton Island Limestone (parts of the Hyd Group) on northern Kuiu and Kupreanof Islands (Muffler, 1967;Brew and others, 1984); and (3) (Loney and others, 1975;Johnson and Karl, 1985) and unnamed basalt near Haines Redman and others, 1984; E. C. Robertson, written commun., 1984;Davis and Plafker, 1985). The Goon Dip Greenstone is assigned a Triassic(?)…”

“…Unit consists of (1) volcanic rocks (Gravina Island Formation) on Gravina Island (Berg andothers, 1978, 1988); (2) unnamed rocks on Annette and Revillagigedo Islands and adjacent areas of mainland (Berg andothers, 1978, 1988;Eberlein and others, 1983); (3) unnamed rocks in the Etolin-Kupreanof Islands region and adjacent areas of mainland (Brew and others, 1984;Buddington and Chapin, 1929); (4) the Douglas Island Volcanics and the Brothers Volcanics (part of Stephens Passage Group) on and near Admiralty Island (Lathram and others, 1965) and in the Juneau area Brew, 1973, 1977;Brew and Ford, 1985); and (5) part of the now-abandoned Berners Formation (strata reassigned, in part, to the Douglas Island Volcanics) northwest of Juneau (Knopf, 1912;Martin, 1926;Brew and Ford, 1985) Sedimentary and volcanic rocks, undivided (Cretaceous and Jurassic)-Moderately deformed and metamorphosed graywacke, mudstone, sandstone, and andesitic to basaltic rocks. Strata belong to the Shelter Formation in southern Lynn Canal (Barker,195 7) and are undifferentiated correlatives of the Treadwell Slate (unit KJs), the Seymour Canal Formation (unit KJs), and the Douglas Island Volcanics (unit KJv) near Juneau Brew, 1973, 1977;Brew and Ford, 1985 (Berg, 1982;Gehrels and others, 1987); (2) and basalt (Chapin Peak Formation; part of the Hyd Group) on Gravina Island (Berg, 1982;Berg andothers, 1978, 1988;others, 1986, 1987); and (3) rhyolite and subordinate basalt (Keku Volcanics) and basalt and andesite (Hound Island Volcanics; part of the Hyd Group) in Keku Strait (Muffler, 1967;Brew and others, 1984 (Berg andothers, 1978, 1988;Gehrels and others, 1987); (2) unnamed strata in the belt of disrupted rocks (units KDsd and KDvd) on Kupreanof and Zarembo Islands (Brew, 1982;Brew and others, 1984;…”

“…Unit consists of ( 1) the Gravina Island Formation and unnamed strata on Gravina Island (Berg andothers, 1978, 1988 ); (2) unnamed strata on Annette Island, Revillagigedo Island, southern Etolin Island, and adjacent parts of mainland (Berg andothers, 1978, 1988;Eberlein and others, 1983); (3) the Seymour Canal Formation (part of the Stephens Passage Group) and its metamorphic equivalents near Etolin and Kupreanof Islands and adjacent areas of mainland (Buddington and Chapin, 1929;Brew and others, 1984); (4) an unnamed unit of sandstone and mudstone in Keku Strait (Muffler, 1967); (5) the Seymour Canal Formation on Admiralty Island (Lathram and others, 1965), northern Kupreanof Island (Brew and others, 1984), and perhaps near Cape Fanshaw (Muffler, 1967;Buddington and Chapin, 1929); (6) the now-abandoned Symonds Formation (strata reassigned to the Seymour Canal Formation) and the Shelter Formation on islands in southern Lynn Canal (Barker, 1957;Brew and Ford, 1985); (7) the Treadwell Slate and unnamed strata near Juneau Brew, 1973, 1977;Brew and Ford, 1985); (8) part of the nowabandoned Berners Formation (strata reassigned, in part, to the Seymour Canal Formation) northwest of Juneau (Knopf, 1911(Knopf, , 1912Martin, 1926;Buddington and Chapin, 1929;Redman, 1984a;Brew and Ford, 1985); and (9) (Irvine, 1973(Irvine, , 1974 and possibly to Early Cretaceous and (or) Jurassic diorite (KJd) and gabbro (KJgb) (Berg and others, RV 1978RV , 1988. Unit consists of (1) volcanic rocks (Gravina Island Formation) on Gravina Island (Berg andothers, 1978, 1988); (2) unnamed rocks on Annette and Revillagigedo Islands and adjacent areas of mainland (Berg andothers, 1978, 1988;…”