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REFERENCES CITED Albee, A. L., and Ray, Llly, 1970, Correction factors for elec-n probe microanalysis of silicates, oxides, carbonates, phosphates, and sultetes: Analytical Chemistry, v. 42, no. 12, p. 1408- 1414. Bence, A. E., and Albee, A. L., 1968, Empirical correction faotors for the electron microanalysis of silicates and oddes: Journal of Geology, v. 76, no. 4, p. 382-403: Coleman, R. G., Lee, t). E., Beatty, L. B., and Bannock, We W., 1065, EclogItes and eclogites: Theit differences and similarities: Goologiaal Society of America Wetin, v. 76, no. 5, p. 483- 508. Hlb, D. J., and Oreen, D. R, 1979, An experimental stuQ of the effect of Ca upon garnet- chopyroxene Fe-Mg exchange equilibria: Con- trtbutions to Mineralogy and Petrology, v. 71, no. 1, p. 13-22. Eugster, H. P., Albee, A. L., Bence, A. B., lllornpson, J. B., Jr., and Waldbaurn, D. R., 1972, The two- phase reglon and excess mixing properties of paragonitemuscovite crystalline solutions: Journal of Petrology, v. 13, no. 1, p. 147-179. Holland, T. J. B., 1979, Reversed hydrothermal deter- minatlon of jadeitediopside activities labs.]: Eos (American Eeophysfaal Union Transactions), v. 60, no. 18, p. 405. -1980, The reaction albite=jadeIte+quariz deter- mined experimentally in the range 600-1200~~: American Mlneralogkt, v. 65, no. 1-2, p. 129- 134. Laird, Jo, and Albee, A. L., 1981, High-pressure metamorphism in mafic schist from northern Vermont: American Jourha) of Science, v. 281, no. 2, p. 97-126. Mlyashlro, Aklho, 1973, Metamorphism and metamor- phic belts: New York, WIley, 492 p. Raheim, Arne, and Green, D. H., 1974, Experimental determination of the tempera- and pcessure dependence of the Fe-Mg partition coefficient for coexisting garnet and clinopyroxene: Contri- butions to Mineralogy and Petrology, V. 48, no. 3, p. 179-203. Swalnbank, R. C., and Forbes, R. B., 1975, Petrology of eclagitic cocks from the Fairbanks district, &ke, & Forbes, R. B., ed., Contrlhtions to geology of the Bering Sea Basin and adjacent regionsr Geological Society of Am erlca Special Paper 151, p. 77-123. Thompson, A. B., and Algor, J. R, 1977, Model sgs- tems for anatexis of pelitic rocks; I. Theory of melting reactions in the +em KAlO -NaA102- A1 0 -SO2-HZO: Contributions 0 &herdogy an8 8etrology, v. 63, no. 3, p. 247-268. Paleomic lim- of the (Xaey Mamtaim and vidnity, Clrcle qwkmgle, east-o~trdl Alsaka By Betea L Poster, Fbmnm R Weber, sad J. Tbbmas DWm, Jr. The Crazy Mountaim, fn the northern part of the Circle quadrangle (area 9, fig. 23), could have been named by a geologist because of their numerous geologic puzzles. The many prominent limestone outcrops are among the enigmas to be solved. Steepsided light-colored limestome outcrops are visible across the landscape of both the eastern and western Crazy Mountains for many kilometers. One Umestone unit in the eastern Crazy Mountains can be traced from a fairly broad outcrop area in the east, Figure 36.-Sketch map showing sample localities and numbers and location of Emsian Umestone and associated I sedlrnentary rocks and Lower cambrim(?) limestone in vicinity of the eastern Crazy Mountains, Circle 1 quadrangle, Ataska. I
westward into a narrow band that extends cross cow- try along a nearly straight come for more than 19 km (fig. 36). In the weatern Crazy Mountains, siinfler- appeering Umestone occurs in several outcrops, possibly isolated by faulting or erdon. Most of the large outcrop (fig. 37) In the eastern Crazy Mountalns weather gray and are of medium- light-gray to medium-gray Umestone wlth yellowish- brown mottling. A minor amount of darkgray limestone occurs looally, and a few darkway smooth- surfaced dolomite beds are interlnyered. The lime stone is fine grained with incipient recrystallization; it is generally masslve but may be thin bedded locally. Commonly, small white calcite veins and veinlets Lace the outcrop. The limeatone generally has a spongy- appearing solutionpf tted surface; rillenstein and other small solution features occur. Figure 37.-Typical outcrop of Ernsian limestone in the eastern Cmzy Mountains. View westward. At two loudtias, corals Vlat were collected in 1980 suggest an Early Devonian age, These corals were identified by W. A. Oliver, Jr., who reported from one locality: "80A Fr 307 (USGS 10314-SD), see. 8, T. 10 N., R. 14 E.; Circle C-2 quadrangle. closely related $ecies of ~artind~h~llum &d cl. Spangonaria are Emsian. Also present are indeterminate bryozoans and the two-holed cdnoid wide Gasterocoma bicaula Johnson and Lane. J. T. Dutro , Jr., indicated an Emsian-early Eifelian agerange for the distinctive crinoid ossicle; the consensus is that the most likely age is Emsian (late Early Devonian). h Emsian age is also supported by data from conodonts (Anita Harris, oral commun., 1981). Fieldwork in 1981 shows that much of the limestone in the eastern Crazy Mountains, on trend .with locality 103144D, contalm the two- holed crinoids and that the entire outcrop belt may reasonably be dated by this collection as probable Bmsian. Another collection, BOA Wr 312 (UWS 10315- SD), to the west b the Circle M quadr-e, westm Crazy Mountains (fig. 961, contains, according to Oliver: Amphlpora, StrIatopora, Syringopora, cf. Pseudoplasmopora, and cf. Spinolasrna. Tnis collection h also kly Devonian but may be slightly Older Lhan collection 10314-SD. Conodonts also indicate a slightly older age for this limestone (Anita Hawis, oral Corn mun., 1981). The stratigraphic and structural relations of the rocks adjoidng the Umestone are unclear. In the eastern Crazy Mountah, the Ilmestone, on the south, has a covered contact with a thick coarse chert-pebble congumerate of unknown age and attitude. To the north, the Urnatone lles in apparently unconformable (covered) contact with a sequence of rocks including a thlck very dark gray, nearly black arenaoeous Lime stone, olive, green, maroon, and gray argillite, a lew thin beds of chert, and a thick section of quartzite and stltstone. OUve argillite has yielded the Early Cam- brian trace fossil Oldhamla (Chuckin and Brabb, 1965). The nature of both the north and south contacts of this limestone b uncertain, and neither wmnforrn- ities nor fault contacts completely satisfy the mapped geologic relstiona. Faunal evidence for post-Devonian cocks in the main part of the mazy Mountains is absent, except lor the occurrence of late Paleozoic and early Mesozoic radiolarims (D. L. Jones and others, written cornmun., 1981) in chert associated with mafic igneous rocks that crop out in the northern part of the study area and are included in the Circle Volcanics (Mertie, 1937). A different sequence of Limestone and clastic rocks crops out on the south bank of the North Pork of Preacher Creek, just south of the western Crazy Mountalns. In exposures along the high bluff, about 300 m of massive-appearing bedded limestone contalns plsotites, spongellke bodies, and possible wchaeo- cyathlds. This Limestone weathers medium gray and is cream cobred on some vertical surfaces; it k generally medium gray on fresh surfaces and is fine grained but mostly recrystallized. The limestone beds are 2.5 to 30 cm thiak. Medium-gray very fine grained limy mudstone, some of which is finely laminated with millimeter-thiok tan-colored siliceous layers, is locally interbedded. Thin bands of black chert nodules or lenses also occur, but they rue rare. Stylolites are present in some of the very fine grained lImy mudstone. This Umestone, on the west side, is in probable fault contact with red and green argillite, darkgray to black limestone, dolomite, and basalt, inchding pilow basalt. Its lithology and pwlble faunal content suggest a correlation with the Lower Cambrian Funnel Creek limestone of the Tatonduk fiver area (Brabb, 1967). The adjacent rocks have Uthologies suggestive of part of the Tindir Group (Proterozoic). Although these rocks include maroon and green argillite, they are unlike any other lithologic sequence seen in the Yukon-Tanana Upland. The block containing this un- usual group of rocks appears to be exotic: it might have moved in from the southeast, possibly caught up between two fault strands of the Tintins Eault system (fig. 36).
Page 1 and 2:
n Alas Accompli: ' I.S. GE OLOGI CA
Page 3 and 4:
I CONTENTS Page A bst raet ........
Page 5 and 6:
-- --A I ALASEU i nued rral expluru
Page 7 and 8:
........ igure .JB. ;5~ercn map ox
Page 9 and 10:
. , ".,k a. ,.e ,\a 1 y U11 IIIUUII
Page 11:
THE UNITED STATES GEOLOGICAL SURVEY
Page 15 and 16:
~ t I r n t S i m ~ ~ Alarr a ~ man
Page 17 and 18:
I -1977, RelImlnary documentat!on l
Page 19 and 20: I I MaCenn, W. R., Perez, 0. J., an
Page 21 and 22: were deslgned to impMve the accurac
Page 23 and 24: Noatak Sandstom and is overlaln con
Page 25 and 26: I (Nilsen and others, 1981a); (2) f
Page 27 and 28: I that contains the Upper Devonian
Page 29 and 30: who found Westeqaardodina sp., posb
Page 31 and 32: Table 2 lists the means rtnd for th
Page 33 and 34: ' Noatak Vdley (fig. 129. This ice
Page 35 and 36: 3 EUMN OF MAP UNITS WAmWARY OUAERNA
Page 37 and 38: -om displacement of the cc tween th
Page 39 and 40: I US I Surlicial dcnrrua,ts [~dater
Page 41 and 42: I Plafker, George, Hudson, Travis,
Page 43 and 44: !omlensed iring vapors generated by
Page 45 and 46: and the thinning. -upward cycles .,
Page 47 and 48: Kellum, L. B., Devless, S. N., and
Page 49 and 50: 1912 sample (a mediumwey pumice blo
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: (Mg3.09 pe2+ 0.69 pe 0.~1~0.01~~0.9
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 and 102: Joreskog, K. G., Klovan, J. E., and
Page 103 and 104: Mineral qItWation end r ~ k t k W e
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
Page 153 and 154:
Gecllogical Survey Open-File Report
Page 155 and 156:
I provenance, and tectonia sIgnific
Page 157 and 158:
Keith, T. E. C, Barnes, Ivan, afrd
Page 159 and 160:
Open-Flle Report 8P811C, 19 p. + 2
Page 161 and 162:
United States Qeological Survey in
Page 163 and 164:
, ,. nldslra poblisbe!d by Prior, D
Page 165 and 166:
60, Alaska: Offshore Technology Con
Page 167:
Author Index [Page number underscor
Page 170 and 171:
Parks. Bruce ......................
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