Elemental, isotopic and Ar40/39Ar data of the lake Carnegie Eucrite, old homestead 003 Howardite, and anomalous basaltic Achondrite Deakin 010
Introduction: Petrography, electron microprobe major and trace elements, oxygen isotope s and 40 Ar/ 39 Ar thermo-chronometry of a new cumulate eucrite (Lake Carnegie), a brecciated eucrite - like basaltic achondrite (Deakin 010), and a howardite (Old Homestead 003) from Western Australia are presen...
| Main Authors: | , , , , , , |
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| Format: | Conference Paper |
| Published: |
2012
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| Online Access: | http://hdl.handle.net/20.500.11937/3139 |
| _version_ | 1848744149591785472 |
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| author | Kennedy, T. Jourdan, F. Bevan, Alexander Gee, M. Downes, P. Cliff, J. Frew, A. |
| author_facet | Kennedy, T. Jourdan, F. Bevan, Alexander Gee, M. Downes, P. Cliff, J. Frew, A. |
| author_sort | Kennedy, T. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Introduction: Petrography, electron microprobe major and trace elements, oxygen isotope s and 40 Ar/ 39 Ar thermo-chronometry of a new cumulate eucrite (Lake Carnegie), a brecciated eucrite - like basaltic achondrite (Deakin 010), and a howardite (Old Homestead 003) from Western Australia are presented. Results and Discussion: Lake Carnegie is an equilibrated cumulate eucrite comprised of low-Ca pyroxene (Fs 29-61 , En 2 9-40 , Wo 5-42 ) and calcic plagioclase (An 91-9 7 , Ab 3-8 , Or 0-0.5 ) . Deakin 010 is a brecciated monomict eucrite and is comprised of low-Ca pyroxene (Fs 24-64 , En 27-36 , Wo 1-46 ) and calcic plagioclase (An 8 6-9 7 , Ab 3-11 , Or 0-3 ). Old Homestead 003 is a breccia of lithic clasts including eucrite fragments (some with sub - ophitic texture), and a minor diogenite component in a clastic, welded matrix of mineral fragments, and glass. Mineralogically, Old Homestead 003 includes rare olivine (Fa 4-4 6 , Fo 54-96 ,), Ca - pyroxene (Fs 9-6 8 , En 3-7 8 , Wo 1-86 ) and calcic plagioclase (An 88-9 7 , Ab 3-11 , Or 0.1-0. 8 ). Mineral compositions in Lake Carnegie and Deakin 010 indicate similar magmatic origins to other eucrites, and the Fe/Mn ratios of ferro-magnesian silicates in both eucrites and the howardite indicate an origin from the HED parent body [1], considered to be asteroid 4 Vesta [2,3]. For Lake Carnegie and Old Homestead 003, mineral-specific oxygen isotopic compositions support an origin on the HED parent body.However, in Deakin 010 oxygen is o topic compositions plot near the TFL and indicate an affinity with previously d e scribed anomalous basaltic achondrites, such as Bunburra Rockhole [4,5]. High-resolution 40 Ar/ 39 Ar thermochronometry dating of Lake Carnegie (4507 ± 20 Ma) suggests a mega impact at this time, Deakin 010 (3351 ± 65 Ma, ≥ 3.7 Ga, 3482 ± 36 Ma), and Old Homestead 003 (≥ 3.7 Ga) yielded only partially reset ages. Two other eucrites, Millbillillie (3722 ± 55 Ma, 3579 ± 28 Ma, 3313 ± 174 Ma) and Camel Donga (3693 ± 51 Ma) yielded an unprecedented number of well-defined plateau ages obtained on various mineral phases, and attributed to various impact events. |
| first_indexed | 2025-11-14T05:56:53Z |
| format | Conference Paper |
| id | curtin-20.500.11937-3139 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T05:56:53Z |
| publishDate | 2012 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-31392017-01-30T10:28:47Z Elemental, isotopic and Ar40/39Ar data of the lake Carnegie Eucrite, old homestead 003 Howardite, and anomalous basaltic Achondrite Deakin 010 Kennedy, T. Jourdan, F. Bevan, Alexander Gee, M. Downes, P. Cliff, J. Frew, A. Introduction: Petrography, electron microprobe major and trace elements, oxygen isotope s and 40 Ar/ 39 Ar thermo-chronometry of a new cumulate eucrite (Lake Carnegie), a brecciated eucrite - like basaltic achondrite (Deakin 010), and a howardite (Old Homestead 003) from Western Australia are presented. Results and Discussion: Lake Carnegie is an equilibrated cumulate eucrite comprised of low-Ca pyroxene (Fs 29-61 , En 2 9-40 , Wo 5-42 ) and calcic plagioclase (An 91-9 7 , Ab 3-8 , Or 0-0.5 ) . Deakin 010 is a brecciated monomict eucrite and is comprised of low-Ca pyroxene (Fs 24-64 , En 27-36 , Wo 1-46 ) and calcic plagioclase (An 8 6-9 7 , Ab 3-11 , Or 0-3 ). Old Homestead 003 is a breccia of lithic clasts including eucrite fragments (some with sub - ophitic texture), and a minor diogenite component in a clastic, welded matrix of mineral fragments, and glass. Mineralogically, Old Homestead 003 includes rare olivine (Fa 4-4 6 , Fo 54-96 ,), Ca - pyroxene (Fs 9-6 8 , En 3-7 8 , Wo 1-86 ) and calcic plagioclase (An 88-9 7 , Ab 3-11 , Or 0.1-0. 8 ). Mineral compositions in Lake Carnegie and Deakin 010 indicate similar magmatic origins to other eucrites, and the Fe/Mn ratios of ferro-magnesian silicates in both eucrites and the howardite indicate an origin from the HED parent body [1], considered to be asteroid 4 Vesta [2,3]. For Lake Carnegie and Old Homestead 003, mineral-specific oxygen isotopic compositions support an origin on the HED parent body.However, in Deakin 010 oxygen is o topic compositions plot near the TFL and indicate an affinity with previously d e scribed anomalous basaltic achondrites, such as Bunburra Rockhole [4,5]. High-resolution 40 Ar/ 39 Ar thermochronometry dating of Lake Carnegie (4507 ± 20 Ma) suggests a mega impact at this time, Deakin 010 (3351 ± 65 Ma, ≥ 3.7 Ga, 3482 ± 36 Ma), and Old Homestead 003 (≥ 3.7 Ga) yielded only partially reset ages. Two other eucrites, Millbillillie (3722 ± 55 Ma, 3579 ± 28 Ma, 3313 ± 174 Ma) and Camel Donga (3693 ± 51 Ma) yielded an unprecedented number of well-defined plateau ages obtained on various mineral phases, and attributed to various impact events. 2012 Conference Paper http://hdl.handle.net/20.500.11937/3139 restricted |
| spellingShingle | Kennedy, T. Jourdan, F. Bevan, Alexander Gee, M. Downes, P. Cliff, J. Frew, A. Elemental, isotopic and Ar40/39Ar data of the lake Carnegie Eucrite, old homestead 003 Howardite, and anomalous basaltic Achondrite Deakin 010 |
| title | Elemental, isotopic and Ar40/39Ar data of the lake Carnegie Eucrite, old homestead 003 Howardite, and anomalous basaltic Achondrite Deakin 010 |
| title_full | Elemental, isotopic and Ar40/39Ar data of the lake Carnegie Eucrite, old homestead 003 Howardite, and anomalous basaltic Achondrite Deakin 010 |
| title_fullStr | Elemental, isotopic and Ar40/39Ar data of the lake Carnegie Eucrite, old homestead 003 Howardite, and anomalous basaltic Achondrite Deakin 010 |
| title_full_unstemmed | Elemental, isotopic and Ar40/39Ar data of the lake Carnegie Eucrite, old homestead 003 Howardite, and anomalous basaltic Achondrite Deakin 010 |
| title_short | Elemental, isotopic and Ar40/39Ar data of the lake Carnegie Eucrite, old homestead 003 Howardite, and anomalous basaltic Achondrite Deakin 010 |
| title_sort | elemental, isotopic and ar40/39ar data of the lake carnegie eucrite, old homestead 003 howardite, and anomalous basaltic achondrite deakin 010 |
| url | http://hdl.handle.net/20.500.11937/3139 |