New Paleointensity Data Suggest Possible Phanerozoic-Type Paleomagnetic Variations in the Precambrian
The state of the geomagnetic field throughout the Precambrian era is largely unknown. Approximately 8% of global paleointensity records account for ∼4 billion years of Earth history. Despite this severe sparsity, the data are used to constrain models that predict the timing of significant deep earth...
| Main Authors: | , , |
|---|---|
| Format: | Journal Article |
| Language: | English |
| Published: |
AMER GEOPHYSICAL UNION
2021
|
| Subjects: | |
| Online Access: | http://purl.org/au-research/grants/arc/FL150100133 http://hdl.handle.net/20.500.11937/90606 |
| _version_ | 1848765400687312896 |
|---|---|
| author | Lloyd, S.J. Biggin, A.J. Li, Zheng-Xiang |
| author_facet | Lloyd, S.J. Biggin, A.J. Li, Zheng-Xiang |
| author_sort | Lloyd, S.J. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The state of the geomagnetic field throughout the Precambrian era is largely unknown. Approximately 8% of global paleointensity records account for ∼4 billion years of Earth history. Despite this severe sparsity, the data are used to constrain models that predict the timing of significant deep earth events such as inner core nucleation. This carries with it the assumption that the Precambrian paleomagnetic field was less variable when compared to the Phanerozoic, or at least that the sparse data can be averaged to accurately represent a particular time period. This study reports new paleointensities from the West Australian Craton at 755 Ma (the Mundine Wells dyke swarm) and 1,070 Ma (the Bangemall Sills); both of which occurred within ∼30 Ma from times at which extremely weak and anomalously strong fields, respectively, have been reported. Virtual dipole moments of 6.3 ± 0.1 Am2 × 1022 and 1.8 ± 1.2 Am2 × 1022 have been obtained from the two suites of mafic rock units which are substantially different to the previous measurements for the two respective ages. The findings suggest that field variability over tens of Myrs in the Precambrian was greater than has previously been assumed. This is supported by comparisons of paleosecular variation and distributions of virtual dipole moments. If variability in the Precambrian field is similar to that observed in the Phanerozoic, spatial or temporal anomalies may introduce significant bias to statistical analyses and model constraints, implying that caution should be employed in the interpretation of the Precambrian dipole moment records. |
| first_indexed | 2025-11-14T11:34:39Z |
| format | Journal Article |
| id | curtin-20.500.11937-90606 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:34:39Z |
| publishDate | 2021 |
| publisher | AMER GEOPHYSICAL UNION |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-906062023-03-27T01:49:49Z New Paleointensity Data Suggest Possible Phanerozoic-Type Paleomagnetic Variations in the Precambrian Lloyd, S.J. Biggin, A.J. Li, Zheng-Xiang Science & Technology Physical Sciences Geochemistry & Geophysics paleointensity paleomagnetic secular variation time variations secular and longer PSEUDO-SINGLE-DOMAIN LTD-DHT SHAW GEOMAGNETIC-FIELD ABSOLUTE PALEOINTENSITY COOLING RATE THELLIER LAVA MULTIDOMAIN INTENSITY MAGNETITE The state of the geomagnetic field throughout the Precambrian era is largely unknown. Approximately 8% of global paleointensity records account for ∼4 billion years of Earth history. Despite this severe sparsity, the data are used to constrain models that predict the timing of significant deep earth events such as inner core nucleation. This carries with it the assumption that the Precambrian paleomagnetic field was less variable when compared to the Phanerozoic, or at least that the sparse data can be averaged to accurately represent a particular time period. This study reports new paleointensities from the West Australian Craton at 755 Ma (the Mundine Wells dyke swarm) and 1,070 Ma (the Bangemall Sills); both of which occurred within ∼30 Ma from times at which extremely weak and anomalously strong fields, respectively, have been reported. Virtual dipole moments of 6.3 ± 0.1 Am2 × 1022 and 1.8 ± 1.2 Am2 × 1022 have been obtained from the two suites of mafic rock units which are substantially different to the previous measurements for the two respective ages. The findings suggest that field variability over tens of Myrs in the Precambrian was greater than has previously been assumed. This is supported by comparisons of paleosecular variation and distributions of virtual dipole moments. If variability in the Precambrian field is similar to that observed in the Phanerozoic, spatial or temporal anomalies may introduce significant bias to statistical analyses and model constraints, implying that caution should be employed in the interpretation of the Precambrian dipole moment records. 2021 Journal Article http://hdl.handle.net/20.500.11937/90606 10.1029/2021GC009990 English http://purl.org/au-research/grants/arc/FL150100133 http://purl.org/au-research/grants/arc/DP210102495 http://creativecommons.org/licenses/by/4.0/ AMER GEOPHYSICAL UNION fulltext |
| spellingShingle | Science & Technology Physical Sciences Geochemistry & Geophysics paleointensity paleomagnetic secular variation time variations secular and longer PSEUDO-SINGLE-DOMAIN LTD-DHT SHAW GEOMAGNETIC-FIELD ABSOLUTE PALEOINTENSITY COOLING RATE THELLIER LAVA MULTIDOMAIN INTENSITY MAGNETITE Lloyd, S.J. Biggin, A.J. Li, Zheng-Xiang New Paleointensity Data Suggest Possible Phanerozoic-Type Paleomagnetic Variations in the Precambrian |
| title | New Paleointensity Data Suggest Possible Phanerozoic-Type Paleomagnetic Variations in the Precambrian |
| title_full | New Paleointensity Data Suggest Possible Phanerozoic-Type Paleomagnetic Variations in the Precambrian |
| title_fullStr | New Paleointensity Data Suggest Possible Phanerozoic-Type Paleomagnetic Variations in the Precambrian |
| title_full_unstemmed | New Paleointensity Data Suggest Possible Phanerozoic-Type Paleomagnetic Variations in the Precambrian |
| title_short | New Paleointensity Data Suggest Possible Phanerozoic-Type Paleomagnetic Variations in the Precambrian |
| title_sort | new paleointensity data suggest possible phanerozoic-type paleomagnetic variations in the precambrian |
| topic | Science & Technology Physical Sciences Geochemistry & Geophysics paleointensity paleomagnetic secular variation time variations secular and longer PSEUDO-SINGLE-DOMAIN LTD-DHT SHAW GEOMAGNETIC-FIELD ABSOLUTE PALEOINTENSITY COOLING RATE THELLIER LAVA MULTIDOMAIN INTENSITY MAGNETITE |
| url | http://purl.org/au-research/grants/arc/FL150100133 http://purl.org/au-research/grants/arc/FL150100133 http://hdl.handle.net/20.500.11937/90606 |