Tranquillityite: The last lunar mineral comes down to Earth
Tranquillityite [Fe2+8(ZrY)2Ti3Si3O24] was first discovered in mare basalts collected during the Apollo 11 lunar mission to the Sea of Tranquillity. The mineral has since been found exclusively in returned lunar samples and lunar meteorites, with no terrestrial counterpart. We have now identified tr...
| Main Authors: | , , , , |
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| Format: | Journal Article |
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Geological Society of America
2012
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| Online Access: | http://hdl.handle.net/20.500.11937/44543 |
| _version_ | 1848757031445463040 |
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| author | Rasmussen, Birger Fletcher, Ian Gregory, Courtney Muhling, Janet Suvorova, Alexandra |
| author_facet | Rasmussen, Birger Fletcher, Ian Gregory, Courtney Muhling, Janet Suvorova, Alexandra |
| author_sort | Rasmussen, Birger |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Tranquillityite [Fe2+8(ZrY)2Ti3Si3O24] was first discovered in mare basalts collected during the Apollo 11 lunar mission to the Sea of Tranquillity. The mineral has since been found exclusively in returned lunar samples and lunar meteorites, with no terrestrial counterpart. We have now identified tranquillityite in six dolerite dikes and sills from Western Australia. Terrestrial tranquillityite commonly occurs as clusters of fox-red laths closely associated with baddeleyite and zirconolite in quartz and K-feldspar intergrowths in late-stage interstices between plagioclase and pyroxene. Its composition is relatively uniform, comprising mostly Si, Zr, Ti, and Fe, with minor Al, Mg, Mn, Ca, Nb, Hf, Y, and rare earth elements. Its habit and chemistry are consistent with tranquillityite in lunar basalts, and it has a face-centered-cubic subcell, similar to that of annealed lunar tranquillityite. Unlike coexisting baddeleyite and zirconolite, it is commonly altered to a secondary intergrowth of submicron phases comprising mainly Si, Ti, and Ca, with minor Zr. In situ sensitive high-resolution ion microprobe (SHRIMP) U-Pb geochronology of tranquillityite from sills intruding the Eel Creek Formation, northeastern Pilbara Craton, yields a 207Pb/206Pb age of 1064 ± 14 Ma. This age indicates that the previously undated sills belong to the ca. 1070 Ma Warakurna large igneous province, extending the geographic range of this mafic complex. The date also provides a new minimum age (>1.05 Ga) for the intruded sedimentary rocks, which were previously thought to be Neoproterozoic. Examination of dolerite from Western Australia suggests that tranquillityite is a relatively widespread, albeit volumetrically minor, accessory mineral and, where sufficiently coarse, it represents an exceptional new U-Pb geochronometer. |
| first_indexed | 2025-11-14T09:21:38Z |
| format | Journal Article |
| id | curtin-20.500.11937-44543 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:21:38Z |
| publishDate | 2012 |
| publisher | Geological Society of America |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-445432017-09-13T15:59:27Z Tranquillityite: The last lunar mineral comes down to Earth Rasmussen, Birger Fletcher, Ian Gregory, Courtney Muhling, Janet Suvorova, Alexandra Tranquillityite Apollo 11 U-Pb geochronometer Eel Creek Formation Tranquillityite [Fe2+8(ZrY)2Ti3Si3O24] was first discovered in mare basalts collected during the Apollo 11 lunar mission to the Sea of Tranquillity. The mineral has since been found exclusively in returned lunar samples and lunar meteorites, with no terrestrial counterpart. We have now identified tranquillityite in six dolerite dikes and sills from Western Australia. Terrestrial tranquillityite commonly occurs as clusters of fox-red laths closely associated with baddeleyite and zirconolite in quartz and K-feldspar intergrowths in late-stage interstices between plagioclase and pyroxene. Its composition is relatively uniform, comprising mostly Si, Zr, Ti, and Fe, with minor Al, Mg, Mn, Ca, Nb, Hf, Y, and rare earth elements. Its habit and chemistry are consistent with tranquillityite in lunar basalts, and it has a face-centered-cubic subcell, similar to that of annealed lunar tranquillityite. Unlike coexisting baddeleyite and zirconolite, it is commonly altered to a secondary intergrowth of submicron phases comprising mainly Si, Ti, and Ca, with minor Zr. In situ sensitive high-resolution ion microprobe (SHRIMP) U-Pb geochronology of tranquillityite from sills intruding the Eel Creek Formation, northeastern Pilbara Craton, yields a 207Pb/206Pb age of 1064 ± 14 Ma. This age indicates that the previously undated sills belong to the ca. 1070 Ma Warakurna large igneous province, extending the geographic range of this mafic complex. The date also provides a new minimum age (>1.05 Ga) for the intruded sedimentary rocks, which were previously thought to be Neoproterozoic. Examination of dolerite from Western Australia suggests that tranquillityite is a relatively widespread, albeit volumetrically minor, accessory mineral and, where sufficiently coarse, it represents an exceptional new U-Pb geochronometer. 2012 Journal Article http://hdl.handle.net/20.500.11937/44543 10.1130/G32525.1 Geological Society of America restricted |
| spellingShingle | Tranquillityite Apollo 11 U-Pb geochronometer Eel Creek Formation Rasmussen, Birger Fletcher, Ian Gregory, Courtney Muhling, Janet Suvorova, Alexandra Tranquillityite: The last lunar mineral comes down to Earth |
| title | Tranquillityite: The last lunar mineral comes down to Earth |
| title_full | Tranquillityite: The last lunar mineral comes down to Earth |
| title_fullStr | Tranquillityite: The last lunar mineral comes down to Earth |
| title_full_unstemmed | Tranquillityite: The last lunar mineral comes down to Earth |
| title_short | Tranquillityite: The last lunar mineral comes down to Earth |
| title_sort | tranquillityite: the last lunar mineral comes down to earth |
| topic | Tranquillityite Apollo 11 U-Pb geochronometer Eel Creek Formation |
| url | http://hdl.handle.net/20.500.11937/44543 |