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Calc-alkaline plutonism along the Pacific rim of southern Alaska

Open-File Report 79-953

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Abstract

Field, petrology, and age data on southern Alaska plutonic rocks now enable the delineation of eight calc-alkaline plutonic belts. These belts of plutons or batholithic complexes are curvilinear to linear and trend parallel or subparallel to the continental margin. The belts represent the principal loci of emplacement for plutons of specific ages and although there is spatial or temporal overlap in some cases, they are more commonly spatially and temporally distinct. Intermediate lithologies such as quartz diorite, tonalite, and granodiorite dominate in most of the Belts but granodiorite and granite characterize one. The belts are of Mesozoic or Cenozoic age and plutonism began in six of them at about 195, 175, 120, 75, 60, and 40 m.y. ago; age relations in two are poorly known. Recognition of the belts is important for future studies of regional geology, tectonism, and magmatism along the Pacific rim of southern Alaska.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Calc-alkaline plutonism along the Pacific rim of southern Alaska
Series title:
Open-File Report
Series number:
79-953
Edition:
-
Year Published:
1979
Language:
ENGLISH
Publisher:
U.S. Geological Survey,
Description:
34 p. :ill., maps ;27 cm.