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Title: Ultramafic rocks of the western Idaho suture zone: Asbestos Peak and Misery Ridge

Abstract

The Western Idaho Ultramafic Belt extends northward from the town of Weiser to the northern end of Dworshak Reservoir; in its northern portion most of the ultramafic bodies are localized along the suture zone where the Mesozoic oceanic accreted terranes meet the continental craton. Of the twenty bodies investigated, all are small, all are in fault contact with their metavolcanic and metasedimentary host rocks, all have been metamorphosed, and all display deformational fabrics in at least some portion of the outcrop area, suggesting that deformation continued after peak metamorphism. The degree of metamorphism ranges from incipient serpentinization to attainment of equilibrium in the upper amphibolite facies. Some bodies have been intruded by granitic dikes or pegmatite veins after emplacement, and have locally undergone contact metasomatism. Two particularly complex bodies, Asbestos Peak and Misery Ridge, were chosen for detailed petrographic and chemical study. Asbestos Peak is composed mostly of decussate anthophyllite-talc rock containing isolated patches of harzburgite protolith, and has blackwall border zones. Misery Ridge is composed mostly of coarse-grained sheared tremolite-talc schist without remnant protolith, and lacks true blackwall zones. Both bodies exhibit an unusual and enigmatic hornblende-poikiloblastic garnet-green spinel-skeletal ilmenite assemblage, present in some places as well-defined border zonesmore » and in other places as cross-cutting bodies.« less

Authors:
 [1];  [2]
  1. (Mount Holyoke Coll., South Hadley, MA (United States). Dept. of Geology)
  2. (Univ. of Idaho, Moscow, ID (United States))
Publication Date:
OSTI Identifier:
5126028
Alternate Identifier(s):
OSTI ID: 5126028
Report Number(s):
CONF-9305259--
Journal ID: ISSN 0016-7592; CODEN: GAAPBC
Resource Type:
Conference
Journal Name:
Geological Society of America, Abstracts with Programs; (United States)
Additional Journal Information:
Journal Volume: 25:5; Conference: 89. annual meeting of the Cordilleran Section and the 46th annual meeting of the Rocky Mountain Section of the Geological Society of America (GSA), Reno, NV (United States), 19-21 May 1993; Journal ID: ISSN 0016-7592
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; GEOLOGIC DEPOSITS; GEOCHEMISTRY; PETROGRAPHY; IDAHO; SCHISTS; VOLCANIC ROCKS; CHEMICAL COMPOSITION; DEFORMATION; GEOLOGIC FAULTS; GEOLOGIC HISTORY; METAMORPHISM; MINERALOGY; OCEANIC CRUST; PLATE TECTONICS; SUBDUCTION ZONES; CHEMISTRY; DEVELOPED COUNTRIES; EARTH CRUST; GEOLOGIC FRACTURES; GEOLOGIC STRUCTURES; GEOLOGY; IGNEOUS ROCKS; METAMORPHIC ROCKS; NORTH AMERICA; ROCKS; TECTONICS; USA 580000* -- Geosciences

Citation Formats

Godchaux, M.M., and Bonnichsen, B.. Ultramafic rocks of the western Idaho suture zone: Asbestos Peak and Misery Ridge. United States: N. p., 1993. Web.
Godchaux, M.M., & Bonnichsen, B.. Ultramafic rocks of the western Idaho suture zone: Asbestos Peak and Misery Ridge. United States.
Godchaux, M.M., and Bonnichsen, B.. Thu . "Ultramafic rocks of the western Idaho suture zone: Asbestos Peak and Misery Ridge". United States.
@article{osti_5126028,
title = {Ultramafic rocks of the western Idaho suture zone: Asbestos Peak and Misery Ridge},
author = {Godchaux, M.M. and Bonnichsen, B.},
abstractNote = {The Western Idaho Ultramafic Belt extends northward from the town of Weiser to the northern end of Dworshak Reservoir; in its northern portion most of the ultramafic bodies are localized along the suture zone where the Mesozoic oceanic accreted terranes meet the continental craton. Of the twenty bodies investigated, all are small, all are in fault contact with their metavolcanic and metasedimentary host rocks, all have been metamorphosed, and all display deformational fabrics in at least some portion of the outcrop area, suggesting that deformation continued after peak metamorphism. The degree of metamorphism ranges from incipient serpentinization to attainment of equilibrium in the upper amphibolite facies. Some bodies have been intruded by granitic dikes or pegmatite veins after emplacement, and have locally undergone contact metasomatism. Two particularly complex bodies, Asbestos Peak and Misery Ridge, were chosen for detailed petrographic and chemical study. Asbestos Peak is composed mostly of decussate anthophyllite-talc rock containing isolated patches of harzburgite protolith, and has blackwall border zones. Misery Ridge is composed mostly of coarse-grained sheared tremolite-talc schist without remnant protolith, and lacks true blackwall zones. Both bodies exhibit an unusual and enigmatic hornblende-poikiloblastic garnet-green spinel-skeletal ilmenite assemblage, present in some places as well-defined border zones and in other places as cross-cutting bodies.},
doi = {},
journal = {Geological Society of America, Abstracts with Programs; (United States)},
issn = {0016-7592},
number = ,
volume = 25:5,
place = {United States},
year = {1993},
month = {4}
}

Conference:
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