Transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the Antarctic ureilite Frontier Mountain 90054: Implications for thermal history
Frontier Mountain (FRO) 90054, from Antarctica, is a rare clino- and orthopyroxene-bearing ureilite with a coarse equigranular oriented texture (grains up to 3 mm); it is classified as a low-shock Ca-rich type. The crystal chemistry of its clinopyroxene (Wo(39.3)En(54.6)Fs(6.1)), orthopyroxene (En(8...
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University of Arizona:Geosciences Department, 4717 East Fort Lowell Road:Tucson, AZ 85718:(520)881-0857, EMAIL: baier@meteoritics.org, Fax: (520)881-0554
1997
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ftunivpadovairis:oai:www.research.unipd.it:11577/106713 2024-02-11T09:58:27+01:00 Transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the Antarctic ureilite Frontier Mountain 90054: Implications for thermal history TRIBAUDINO M FIORETTI AM MARTIGNAGO, FEDORA MOLIN, GIANMARIO Tribaudino, M Fioretti, Am Martignago, Fedora Molin, Gianmario 1997 STAMPA http://hdl.handle.net/11577/106713 eng eng University of Arizona:Geosciences Department, 4717 East Fort Lowell Road:Tucson, AZ 85718:(520)881-0857, EMAIL: baier@meteoritics.org, Fax: (520)881-0554 info:eu-repo/semantics/altIdentifier/wos/WOS:A1997XX82800008 volume:32 issue:5 firstpage:671 lastpage:678 numberofpages:8 journal:METEORITICS & PLANETARY SCIENCE http://hdl.handle.net/11577/106713 ORTHO-PYROXENE STRUCTURE-REFINEMENT ULTRAMAFIC NODULES ORDER-DISORDER MINERALOGY DIOPSIDE SYSTEM AUGITE MICROSTRUCTURE CONSTRAINTS info:eu-repo/semantics/article 1997 ftunivpadovairis 2024-01-24T17:34:06Z Frontier Mountain (FRO) 90054, from Antarctica, is a rare clino- and orthopyroxene-bearing ureilite with a coarse equigranular oriented texture (grains up to 3 mm); it is classified as a low-shock Ca-rich type. The crystal chemistry of its clinopyroxene (Wo(39.3)En(54.6)Fs(6.1)), orthopyroxene (En(84.2)Fs(11)Wo(4.8)) and olivine (Fa(12.6)Fo(86.9)) was investigated by single-crystal x-ray structural refinements and transmission electron microscope (TEM) observations to obtain data on the evolutionary history of the parent body. The M1 octahedron and unit cell volumes of the orthopyroxene and clinopyroxene are consistent with low-pressure crystallization. The closure temperatures for intracrystalline Mg-Fe2+ ordering yielded values of 674 degrees C and 804 degrees C for opx and 596 degrees C for cpx, which indicate high-temperature equilibration and fast cooling. Trasmission electron microscope investigations were performed on clinopyroxene, orthopyroxene and pigeonite. The (100) twin lamellae in the clinopyroxene and intergrowth of clino- and orthoenstatite lamellae in orthopyroxene most probably originated by deformation. Exsolution was not observed in any of the phases, which suggests rapid cooling. Analysis by TEM also revealed interstitial Na-rich glass and pigeonite with sharp h+k odd reflections and rare stacking faults parallel to (100). Textural and crystal chemical data, obtained by TEM, indicated rapid cooling that was probably due to fast radiative heat loss as a result of the disintegration of the parent body into small fragments, which subsequently reassembled into a larger body. One or more collisional events caused fine-scale stacking faults and partial melting. Article in Journal/Newspaper Antarc* Antarctic Antarctica Padua Research Archive (IRIS - Università degli Studi di Padova) Antarctic Frontier Mountain ENVELOPE(160.333,160.333,-72.983,-72.983) The Antarctic |
institution |
Open Polar |
collection |
Padua Research Archive (IRIS - Università degli Studi di Padova) |
op_collection_id |
ftunivpadovairis |
language |
English |
topic |
ORTHO-PYROXENE STRUCTURE-REFINEMENT ULTRAMAFIC NODULES ORDER-DISORDER MINERALOGY DIOPSIDE SYSTEM AUGITE MICROSTRUCTURE CONSTRAINTS |
spellingShingle |
ORTHO-PYROXENE STRUCTURE-REFINEMENT ULTRAMAFIC NODULES ORDER-DISORDER MINERALOGY DIOPSIDE SYSTEM AUGITE MICROSTRUCTURE CONSTRAINTS TRIBAUDINO M FIORETTI AM MARTIGNAGO, FEDORA MOLIN, GIANMARIO Transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the Antarctic ureilite Frontier Mountain 90054: Implications for thermal history |
topic_facet |
ORTHO-PYROXENE STRUCTURE-REFINEMENT ULTRAMAFIC NODULES ORDER-DISORDER MINERALOGY DIOPSIDE SYSTEM AUGITE MICROSTRUCTURE CONSTRAINTS |
description |
Frontier Mountain (FRO) 90054, from Antarctica, is a rare clino- and orthopyroxene-bearing ureilite with a coarse equigranular oriented texture (grains up to 3 mm); it is classified as a low-shock Ca-rich type. The crystal chemistry of its clinopyroxene (Wo(39.3)En(54.6)Fs(6.1)), orthopyroxene (En(84.2)Fs(11)Wo(4.8)) and olivine (Fa(12.6)Fo(86.9)) was investigated by single-crystal x-ray structural refinements and transmission electron microscope (TEM) observations to obtain data on the evolutionary history of the parent body. The M1 octahedron and unit cell volumes of the orthopyroxene and clinopyroxene are consistent with low-pressure crystallization. The closure temperatures for intracrystalline Mg-Fe2+ ordering yielded values of 674 degrees C and 804 degrees C for opx and 596 degrees C for cpx, which indicate high-temperature equilibration and fast cooling. Trasmission electron microscope investigations were performed on clinopyroxene, orthopyroxene and pigeonite. The (100) twin lamellae in the clinopyroxene and intergrowth of clino- and orthoenstatite lamellae in orthopyroxene most probably originated by deformation. Exsolution was not observed in any of the phases, which suggests rapid cooling. Analysis by TEM also revealed interstitial Na-rich glass and pigeonite with sharp h+k odd reflections and rare stacking faults parallel to (100). Textural and crystal chemical data, obtained by TEM, indicated rapid cooling that was probably due to fast radiative heat loss as a result of the disintegration of the parent body into small fragments, which subsequently reassembled into a larger body. One or more collisional events caused fine-scale stacking faults and partial melting. |
author2 |
Tribaudino, M Fioretti, Am Martignago, Fedora Molin, Gianmario |
format |
Article in Journal/Newspaper |
author |
TRIBAUDINO M FIORETTI AM MARTIGNAGO, FEDORA MOLIN, GIANMARIO |
author_facet |
TRIBAUDINO M FIORETTI AM MARTIGNAGO, FEDORA MOLIN, GIANMARIO |
author_sort |
TRIBAUDINO M |
title |
Transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the Antarctic ureilite Frontier Mountain 90054: Implications for thermal history |
title_short |
Transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the Antarctic ureilite Frontier Mountain 90054: Implications for thermal history |
title_full |
Transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the Antarctic ureilite Frontier Mountain 90054: Implications for thermal history |
title_fullStr |
Transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the Antarctic ureilite Frontier Mountain 90054: Implications for thermal history |
title_full_unstemmed |
Transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the Antarctic ureilite Frontier Mountain 90054: Implications for thermal history |
title_sort |
transmission electron microscope texture and crystal chemistry of coexisting ortho- and clinopyroxene in the antarctic ureilite frontier mountain 90054: implications for thermal history |
publisher |
University of Arizona:Geosciences Department, 4717 East Fort Lowell Road:Tucson, AZ 85718:(520)881-0857, EMAIL: baier@meteoritics.org, Fax: (520)881-0554 |
publishDate |
1997 |
url |
http://hdl.handle.net/11577/106713 |
long_lat |
ENVELOPE(160.333,160.333,-72.983,-72.983) |
geographic |
Antarctic Frontier Mountain The Antarctic |
geographic_facet |
Antarctic Frontier Mountain The Antarctic |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:A1997XX82800008 volume:32 issue:5 firstpage:671 lastpage:678 numberofpages:8 journal:METEORITICS & PLANETARY SCIENCE http://hdl.handle.net/11577/106713 |
_version_ |
1790594100238483456 |