Direct age constraints on the magnetism of Jack Hills zircon
A potential record of Earth’s magnetic field going back 4.2 billion years (Ga) ago is carried by magnetite inclusions in zircon grains from the Jack Hills. This magnetite may be secondary in nature, however, meaning that the magnetic record is much younger than the zircon crystallization age. Here,...
| Main Authors: | , , , , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
| Published: |
2023
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| Online Access: | http://hdl.handle.net/20.500.11937/92421 |
| _version_ | 1848765640196751360 |
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| author | Taylor, Richard Reddy, Steven Saxey, David Rickard, William Tang, F. Borlina, C.S. Fu, R.R. Weiss, B.P. Bagot, P. Williams, H.M. Harrison, R.J. |
| author_facet | Taylor, Richard Reddy, Steven Saxey, David Rickard, William Tang, F. Borlina, C.S. Fu, R.R. Weiss, B.P. Bagot, P. Williams, H.M. Harrison, R.J. |
| author_sort | Taylor, Richard |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | A potential record of Earth’s magnetic field going back 4.2 billion years (Ga) ago is carried by magnetite inclusions in zircon grains from the Jack Hills. This magnetite may be secondary in nature, however, meaning that the magnetic record is much younger than the zircon crystallization age. Here, we use atom probe tomography to show that Pb-bearing nanoclusters in magnetite-bearing Jack Hills zircons formed during two discrete events at 3.4 and <2 Ga. The older population of clusters contains no detectable Fe, whereas roughly half of the younger population of clusters is Fe bearing. This result shows that the Fe required to form secondary magnetite entered the zircon sometime after 3.4 Ga and that remobilization of Pb and Fe during an annealing event occurred more than 1 Ga after deposition of the Jack Hills sediment at 3 Ga. The ability to date Fe mobility linked to secondary magnetite formation provides new possibilities to improve our knowledge of the Archean geodynamo. |
| first_indexed | 2025-11-14T11:38:28Z |
| format | Journal Article |
| id | curtin-20.500.11937-92421 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | eng |
| last_indexed | 2025-11-14T11:38:28Z |
| publishDate | 2023 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-924212023-06-29T06:26:23Z Direct age constraints on the magnetism of Jack Hills zircon Taylor, Richard Reddy, Steven Saxey, David Rickard, William Tang, F. Borlina, C.S. Fu, R.R. Weiss, B.P. Bagot, P. Williams, H.M. Harrison, R.J. A potential record of Earth’s magnetic field going back 4.2 billion years (Ga) ago is carried by magnetite inclusions in zircon grains from the Jack Hills. This magnetite may be secondary in nature, however, meaning that the magnetic record is much younger than the zircon crystallization age. Here, we use atom probe tomography to show that Pb-bearing nanoclusters in magnetite-bearing Jack Hills zircons formed during two discrete events at 3.4 and <2 Ga. The older population of clusters contains no detectable Fe, whereas roughly half of the younger population of clusters is Fe bearing. This result shows that the Fe required to form secondary magnetite entered the zircon sometime after 3.4 Ga and that remobilization of Pb and Fe during an annealing event occurred more than 1 Ga after deposition of the Jack Hills sediment at 3 Ga. The ability to date Fe mobility linked to secondary magnetite formation provides new possibilities to improve our knowledge of the Archean geodynamo. 2023 Journal Article http://hdl.handle.net/20.500.11937/92421 10.1126/sciadv.add1511 eng http://creativecommons.org/licenses/by/4.0/ fulltext |
| spellingShingle | Taylor, Richard Reddy, Steven Saxey, David Rickard, William Tang, F. Borlina, C.S. Fu, R.R. Weiss, B.P. Bagot, P. Williams, H.M. Harrison, R.J. Direct age constraints on the magnetism of Jack Hills zircon |
| title | Direct age constraints on the magnetism of Jack Hills zircon |
| title_full | Direct age constraints on the magnetism of Jack Hills zircon |
| title_fullStr | Direct age constraints on the magnetism of Jack Hills zircon |
| title_full_unstemmed | Direct age constraints on the magnetism of Jack Hills zircon |
| title_short | Direct age constraints on the magnetism of Jack Hills zircon |
| title_sort | direct age constraints on the magnetism of jack hills zircon |
| url | http://hdl.handle.net/20.500.11937/92421 |