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Title: Metamorphic facies map of Alaska

A metamorphic-facies of Alaska has been compiled, following the facies-determination scheme of the Working Group for the Cartography of the Metamorphic Belts of the World. Regionally metamorphosed rocks are divided into facies series where P/T gradients are known and into facies groups where only T is known. Metamorphic rock units also are defined by known or bracketed age(s) of metamorphism. Five regional maps have been prepared at a scale of 1:1,000,000; these maps will provide the basis for a final colored version of the map at a scale of 1:2,500,000. The maps are being prepared by the US Geological Survey in cooperation with the Alaska Division of Geological and Geophysical Surveys. Precambrian metamorphism has been documented on the Seward Peninsula, in the Baird Mountains and the northeastern Kuskokwim Mountains, and in southwestern Alaska. Pre-Ordovician metamorphism affected the rocks in central Alaska and on southern Prince of Wales Island. Mid-Paleozoic metamorphism probably affected the rocks in east-central Alaska. Most of the metamorphic belts in Alaska developed during Mesozoic or early Tertiary time in conjuction with accretion of many terranes. Examples are Jurassic metamorphism in east-central Alaska, Early Cretaceous metamorphism in the southern Brooks Range and along the rim of the Yukon-Kovyukukmore » basin, and late Cretaceous to early Tertiary metamorphism in the central Alaska Range. Regional thermal metamorphism was associated with multiple episodes of Cretaceous plutonism in southeastern Alaska and with early Tertiary plutonism in the Chugach Mountains. Where possible, metamorphism is related to tectonism. Meeting participants are encouraged to comment on the present version of the metamorphic facies map.« less
Authors:
; ; ; ;
Publication Date:
OSTI Identifier:
6164210
Report Number(s):
CONF-8505215-
Journal ID: CODEN: AAPGB
Resource Type:
Conference
Resource Relation:
Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States); Journal Volume: 69:4; Conference: AAPG-SEPM-SEG Pacific section meeting, Anchorage, AK, USA, 22 May 1985
Research Org:
Geological Survey, Menlo Park, CA
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; ALASKA; METAMORPHIC ROCKS; CRETACEOUS PERIOD; GEOLOGIC HISTORY; JURASSIC PERIOD; MAPS; METAMORPHISM; TECTONICS; TERTIARY PERIOD; CENOZOIC ERA; FEDERAL REGION X; GEOLOGIC AGES; MESOZOIC ERA; NORTH AMERICA; ROCKS; USA 580100* -- Geology & Hydrology-- (-1989)