New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis
Abstract The Northwest Africa ( NWA ) 2996 meteorite is a lunar regolith breccia with a “mingled” bulk composition and slightly elevated incompatible element content. NWA 2996 is dominated by clasts of coarse‐grained noritic and troctolitic anorthosite containing calcic plagioclase (An#~98) and magn...
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crwiley:10.1111/maps.12056 2024-09-15T18:36:49+00:00 New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis Mercer, Celestine N. Treiman, Allan H. Joy, Katherine H. NASA Cosmochemistry Leverhulme Trust Early Career Fellowship 2013 http://dx.doi.org/10.1111/maps.12056 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmaps.12056 https://onlinelibrary.wiley.com/doi/pdf/10.1111/maps.12056 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Meteoritics & Planetary Science volume 48, issue 2, page 289-315 ISSN 1086-9379 1945-5100 journal-article 2013 crwiley https://doi.org/10.1111/maps.12056 2024-08-27T04:32:43Z Abstract The Northwest Africa ( NWA ) 2996 meteorite is a lunar regolith breccia with a “mingled” bulk composition and slightly elevated incompatible element content. NWA 2996 is dominated by clasts of coarse‐grained noritic and troctolitic anorthosite containing calcic plagioclase (An#~98) and magnesian mafic minerals (Mg#~75), distinguishing it from Apollo ferroan anorthosites and magnesian‐suite rocks. This meteorite lacks basalt, and owes its mingled composition to a significant proportion of coarse‐grained mafic clasts. One group of mafic clasts has pyroxenes similar to anorthosites, but contains more sodic plagioclase (An#~94) distinguishing it as a separate lithology. Another group contains Mg‐rich, very low‐titanium pyroxenes, and could represent an intrusion parental to regional basalts. Other clasts include granophyric K‐feldspar, disaggregated phosphate‐bearing quartz monzodiorites, and alkali‐suite fragments (An#~65). These evolved lithics are a minor component, but contain minerals rich in incompatible elements. Several anorthosite clasts contain clusters of apatite, suggesting that the anorthosites either assimilated evolved rocks or were metasomatized by a liquid rich in incompatible elements. We used Lunar Prospector gamma‐ray spectrometer remote sensing data to show that NWA 2996 is most similar to regoliths in and around the South Pole Aitken ( SPA ) basin, peripheral regions of eastern mare, Nectaris, Crisium, and southern areas of Mare Humorum. However, the mineralogy of NWA 2996 is distinctive compared with Apollo and Luna mission samples, and is likely consistent with an origin near the SPA basin: anorthosite clasts could represent local crustal material, mafic clasts could represent intrusions beneath basalt flows, and apatite‐bearing rocks could carry the SPA KREEP signature. Article in Journal/Newspaper South pole Wiley Online Library Meteoritics & Planetary Science 48 2 289 315 |
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Wiley Online Library |
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English |
description |
Abstract The Northwest Africa ( NWA ) 2996 meteorite is a lunar regolith breccia with a “mingled” bulk composition and slightly elevated incompatible element content. NWA 2996 is dominated by clasts of coarse‐grained noritic and troctolitic anorthosite containing calcic plagioclase (An#~98) and magnesian mafic minerals (Mg#~75), distinguishing it from Apollo ferroan anorthosites and magnesian‐suite rocks. This meteorite lacks basalt, and owes its mingled composition to a significant proportion of coarse‐grained mafic clasts. One group of mafic clasts has pyroxenes similar to anorthosites, but contains more sodic plagioclase (An#~94) distinguishing it as a separate lithology. Another group contains Mg‐rich, very low‐titanium pyroxenes, and could represent an intrusion parental to regional basalts. Other clasts include granophyric K‐feldspar, disaggregated phosphate‐bearing quartz monzodiorites, and alkali‐suite fragments (An#~65). These evolved lithics are a minor component, but contain minerals rich in incompatible elements. Several anorthosite clasts contain clusters of apatite, suggesting that the anorthosites either assimilated evolved rocks or were metasomatized by a liquid rich in incompatible elements. We used Lunar Prospector gamma‐ray spectrometer remote sensing data to show that NWA 2996 is most similar to regoliths in and around the South Pole Aitken ( SPA ) basin, peripheral regions of eastern mare, Nectaris, Crisium, and southern areas of Mare Humorum. However, the mineralogy of NWA 2996 is distinctive compared with Apollo and Luna mission samples, and is likely consistent with an origin near the SPA basin: anorthosite clasts could represent local crustal material, mafic clasts could represent intrusions beneath basalt flows, and apatite‐bearing rocks could carry the SPA KREEP signature. |
author2 |
NASA Cosmochemistry Leverhulme Trust Early Career Fellowship |
format |
Article in Journal/Newspaper |
author |
Mercer, Celestine N. Treiman, Allan H. Joy, Katherine H. |
spellingShingle |
Mercer, Celestine N. Treiman, Allan H. Joy, Katherine H. New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis |
author_facet |
Mercer, Celestine N. Treiman, Allan H. Joy, Katherine H. |
author_sort |
Mercer, Celestine N. |
title |
New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis |
title_short |
New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis |
title_full |
New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis |
title_fullStr |
New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis |
title_full_unstemmed |
New lunar meteorite Northwest Africa 2996: A window into farside lithologies and petrogenesis |
title_sort |
new lunar meteorite northwest africa 2996: a window into farside lithologies and petrogenesis |
publisher |
Wiley |
publishDate |
2013 |
url |
http://dx.doi.org/10.1111/maps.12056 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmaps.12056 https://onlinelibrary.wiley.com/doi/pdf/10.1111/maps.12056 |
genre |
South pole |
genre_facet |
South pole |
op_source |
Meteoritics & Planetary Science volume 48, issue 2, page 289-315 ISSN 1086-9379 1945-5100 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/maps.12056 |
container_title |
Meteoritics & Planetary Science |
container_volume |
48 |
container_issue |
2 |
container_start_page |
289 |
op_container_end_page |
315 |
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1810480538479230976 |