Middle Proterozoic emplacement and deformation of metanorthosite and related rocks in the northeastern Marcy massif, Adirondack Mountains, New York

Fakundiny, R H; Muller, P D

Title: Middle Proterozoic emplacement and deformation of metanorthosite and related rocks in the northeastern Marcy massif, Adirondack Mountains, New York

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Abstract

Geologic mapping in the Elizabethtown and Mount Marcy 15 foot quadrangles in the northeastern Adirondack Mountains has shown that Middle Proterozoic anorthosite suite rocks of the Marcy massif were intruded in at least two temporally distinguishable episodes separated by a period of localized ductile shearing. Strain was concentrated in a 100 m to > 1 km thick zone consisting mainly of metamorphosed gabbroic anorthosite, ferrodiorite, and ferrosyenite gneiss with subordinate granite gneiss, calc-silicate gneiss, amphibolite, and marble. This zone of flat to steeply-dipping layered gneisses, designated the Elizabethtown ductile deformation zone (EDDZ) for exposures along Rt 9 south of Elizabethtown, appears to extend from Lake Champlain on the east to at least Lake Placid on the west. Its upper boundary is most clearly evident where it occurs in olivine metagabbro bodies of Jay and Iron Mountain. Massive metagabbro is sheared and recrystallized into amphibolite gneiss. The lower boundary of the zone is more difficult to map, but commonly lies within contaminated metamorphosed gabbroic anorthosite and ferrodiorite gneiss that characterize the margins of the massif in the area. Rocks of the EDDZ display pervasive mesoscopic S and LS fabrics, but exhibit totally recrystallized microtextures. Kinematic indicators such as winged porphyroclasts andmore »« less

Authors:

Fakundiny, R H ^[1]; Muller, P D ^[2]

Geological Survey, Albany, NY (United States)
State Univ. of New York, Oneonta, NY (United States). Dept. of Earth Sciences

Publication Date:: Mon Mar 01 00:00:00 EST 1993

OSTI Identifier:: 5933766

Report Number(s):: CONF-9303211-
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: 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; Journal ID: ISSN 0016-7592

Country of Publication:: United States

Language:: English

Subject:: 58 GEOSCIENCES; ANORTHOSITES; PETROGENESIS; PETROGRAPHY; GEOLOGIC FORMATIONS; NEW YORK; DEFORMATION; GEOLOGIC HISTORY; GNEISSES; MAPPING; PRECAMBRIAN ERA; RECRYSTALLIZATION; SHEAR; DEVELOPED COUNTRIES; GABBROS; GEOLOGIC AGES; GEOLOGY; IGNEOUS ROCKS; METAMORPHIC ROCKS; NORTH AMERICA; PETROLOGY; PLUTONIC ROCKS; ROCKS; USA; 580000* - Geosciences

Citation Formats


                    Fakundiny, R H, and Muller, P D. Middle Proterozoic emplacement and deformation of metanorthosite and related rocks in the northeastern Marcy massif, Adirondack Mountains, New York.  United States: N. p., 1993. 
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                    Fakundiny, R H, & Muller, P D. Middle Proterozoic emplacement and deformation of metanorthosite and related rocks in the northeastern Marcy massif, Adirondack Mountains, New York.  United States.

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                    Fakundiny, R H, and Muller, P D. 1993.  
        "Middle Proterozoic emplacement and deformation of metanorthosite and related rocks in the northeastern Marcy massif, Adirondack Mountains, New York".  United States.

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@article{osti_5933766,

  title        = {Middle Proterozoic emplacement and deformation of metanorthosite and related rocks in the northeastern Marcy massif, Adirondack Mountains, New York},

  author       = {Fakundiny, R H and Muller, P D},

  abstractNote = {Geologic mapping in the Elizabethtown and Mount Marcy 15 foot quadrangles in the northeastern Adirondack Mountains has shown that Middle Proterozoic anorthosite suite rocks of the Marcy massif were intruded in at least two temporally distinguishable episodes separated by a period of localized ductile shearing. Strain was concentrated in a 100 m to > 1 km thick zone consisting mainly of metamorphosed gabbroic anorthosite, ferrodiorite, and ferrosyenite gneiss with subordinate granite gneiss, calc-silicate gneiss, amphibolite, and marble. This zone of flat to steeply-dipping layered gneisses, designated the Elizabethtown ductile deformation zone (EDDZ) for exposures along Rt 9 south of Elizabethtown, appears to extend from Lake Champlain on the east to at least Lake Placid on the west. Its upper boundary is most clearly evident where it occurs in olivine metagabbro bodies of Jay and Iron Mountain. Massive metagabbro is sheared and recrystallized into amphibolite gneiss. The lower boundary of the zone is more difficult to map, but commonly lies within contaminated metamorphosed gabbroic anorthosite and ferrodiorite gneiss that characterize the margins of the massif in the area. Rocks of the EDDZ display pervasive mesoscopic S and LS fabrics, but exhibit totally recrystallized microtextures. Kinematic indicators such as winged porphyroclasts and S-C fabrics are sporadically developed and provide a regionally ambiguous sense of shear. The authors favor a regional extension origin for the fabrics. Mineral assemblages defining the EDDZ fabrics are consistent with granulite facies conditions during shear-zone development and suggest a lower crustal position. Mapping suggests that the younger anorthosite intrusions were mainly domical and generated a chaotic contact zone typified by block structure and dikes of ferrodiorite, ferromonzonite, and ferrosyenite.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/5933766},
  journal      = {Geological Society of America, Abstracts with Programs; (United States)},

  issn         = {0016-7592},

  number       = ,

  volume       = 25:2,

  place        = {United States},

  year         = {Mon Mar 01 00:00:00 EST 1993},

  month        = {Mon Mar 01 00:00:00 EST 1993}

}

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