Alaska Volcano Observatory - Petrology of three volcanic suites, Umnak and Bogoslof Islands, Aleutian Islands, Alaska

PETROLOGY OF THREE VOLCANIC SUITES, UMNAK AND BOGOSLOF ISLANDS, ALEUTIAN ISLANDS, ALASKA

Byers, F. M., 1961, Petrology of three volcanic suites, Umnak and Bogoslof Islands, Aleutian Islands, Alaska: Geological Society of America Bulletin, v. 72, n. 1, p. 93-128.

DATA TABLES *Not all tables in a publication may be listed. Not all tables from a publication have data entered in the database.

42: Analyses of rocks from Umnak and Bogoslof Islands, Aleutian Islands, Alaska

* Abundance of minor elements determined spectrographically *

43: Quantitative petrographic summary of chemically analyzed rocks from Umnak and Bogoslof Islands.

* Detailed information. See text. *

44: Chemical composition and atomic ratios of augite phenocrysts in anorthite-augite-olivine basalt flow

* *Oxides other than alkalis analyzed by Brynjolf Bruun; alkalis analyzed by W.W. Brannock on flame photometer. Cross indicates after Hess (1949, p. 624-626). *

45: Partial analyses of potassium feldspathized rocks of the volcanic rocks of central Umnak Island, Aleutian Islands, Alaska

* For complete analysis of no. 12, see table 1, no. 12. Alkalis of 12A and 12B analyzed by E.J. Benton, Petrographic Laboratory, U.S. Bureau of Reclamation; total iron, lime and magnesia of 12A and 12B analyzed by Herbert M. Ochs, Denver, Colorado. 12. Slightly altered porphyritic basalt (47 Aby 44) or basalt andesite flow collected near Inanudak Bay (lat 53 17.1 N, long 168 19.8 E). 12A. Moderately altered (uralitized, partially zeolitized) porphyritic basic lava (47 Aby 43A) from isthmus area of Umnak (lat 53 16.7 N, long 168 19.3 E) about 0.7 miles southwest of no. 12. Outcrop areas occur as "Islands" in 12B. 12B. Completely altered (silicified, feldspathized, zeolititized, tourmalinized) rock (47 Aby 43B) collected about 50 feet from 12A. Predominant rock of area. *

46: Computed groundmass (g) compositions of analyzed porphyritic lavas of Umnak and Bogoslof Islands, Aleutian Islands, Alaska (numbers of columns analogous to those in table 1)

47: Minor-element analyses of phenocrysts from two porphyritic basalts of northeastern Umnak Island, Aleutian Islands, Alaska

* * Looked for but not found at indicated limits of detection: Be(0.0001), Ag(0.0001), Mo (0.001), W(0.05), Ge(0.001), Sn(0.002); Pb(0.001), As(0.05), Sb(0.01), Bi(0.001), Zn(0.01), Cd(0.005), Tl(0.005), Y(0.001), La(0.003), Th(0.05), Nb(0.005), Ta(0.1), U(0.1), B(0.001), Cross indicates 0.1-0.3 per cent Ca also present *

48: Comparison of average aphyric basalt from northwestern Umnak with average Columbia basalt

* * From Waters (1955, p. 705) *

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