Possible Eoarchean records of the geomagnetic field preserved in the Isua supracrustal belt, southern West Greenland
Recovering ancient records of Earth's magnetic field is essential for determining the role of the magnetosphere in protecting early Earth from cosmic radiation and atmospheric escape. We present paleomagnetic field tests hinting that a record of Earth's 3.7-billion-year (Ga) old magnetic f...
| Main Authors: | , , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
Wiley
2024
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| _version_ | 1811139337544269824 |
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| author | Nichols, CIO Weiss, BP Eyster, A Martin, CR Maloof, AC Kelly, NM Zawaski, MJ Mojzsis, SJ Watson, EB Cherniak, DJ |
| author_facet | Nichols, CIO Weiss, BP Eyster, A Martin, CR Maloof, AC Kelly, NM Zawaski, MJ Mojzsis, SJ Watson, EB Cherniak, DJ |
| author_sort | Nichols, CIO |
| collection | OXFORD |
| description | Recovering ancient records of Earth's magnetic field is essential for determining the role of the magnetosphere in protecting early Earth from cosmic radiation and atmospheric escape. We present paleomagnetic field tests hinting that a record of Earth's 3.7-billion-year (Ga) old magnetic field may be preserved in the northeastern Isua Supracrustal Belt as a chemical remanent magnetization acquired during amphibolite-grade metamorphism in the banded iron formation. Multiple petrological and geochronological lines of evidence indicate that the northernmost part of Isua has not experienced metamorphic temperatures exceeding 380°C since the Eoarchean, suggesting the rocks have not been significantly heated since magnetization was acquired. We use “pseudo” baked contact tests (intrusions emplaced 3.26–3.5 Ga ago) and a fold test (folding 3.6 Ga ago) to demonstrate that some samples preserve a ca. 3.7 Ga record of the magnetic field. We recover a field strength of >15 µT. This suggests that Earth's magnetic field may have been weak enough to enhance atmospheric escape during the Archean. |
| first_indexed | 2024-09-25T04:04:29Z |
| format | Journal article |
| id | oxford-uuid:01bfd667-26a0-4c0e-8dc9-b4691cbaba9f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-09-25T04:04:29Z |
| publishDate | 2024 |
| publisher | Wiley |
| record_format | dspace |
| spelling | oxford-uuid:01bfd667-26a0-4c0e-8dc9-b4691cbaba9f2024-05-29T11:44:40ZPossible Eoarchean records of the geomagnetic field preserved in the Isua supracrustal belt, southern West GreenlandJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:01bfd667-26a0-4c0e-8dc9-b4691cbaba9fEnglishSymplectic ElementsWiley2024Nichols, CIOWeiss, BPEyster, AMartin, CRMaloof, ACKelly, NMZawaski, MJMojzsis, SJWatson, EBCherniak, DJRecovering ancient records of Earth's magnetic field is essential for determining the role of the magnetosphere in protecting early Earth from cosmic radiation and atmospheric escape. We present paleomagnetic field tests hinting that a record of Earth's 3.7-billion-year (Ga) old magnetic field may be preserved in the northeastern Isua Supracrustal Belt as a chemical remanent magnetization acquired during amphibolite-grade metamorphism in the banded iron formation. Multiple petrological and geochronological lines of evidence indicate that the northernmost part of Isua has not experienced metamorphic temperatures exceeding 380°C since the Eoarchean, suggesting the rocks have not been significantly heated since magnetization was acquired. We use “pseudo” baked contact tests (intrusions emplaced 3.26–3.5 Ga ago) and a fold test (folding 3.6 Ga ago) to demonstrate that some samples preserve a ca. 3.7 Ga record of the magnetic field. We recover a field strength of >15 µT. This suggests that Earth's magnetic field may have been weak enough to enhance atmospheric escape during the Archean. |
| spellingShingle | Nichols, CIO Weiss, BP Eyster, A Martin, CR Maloof, AC Kelly, NM Zawaski, MJ Mojzsis, SJ Watson, EB Cherniak, DJ Possible Eoarchean records of the geomagnetic field preserved in the Isua supracrustal belt, southern West Greenland |
| title | Possible Eoarchean records of the geomagnetic field preserved in the Isua supracrustal belt, southern West Greenland |
| title_full | Possible Eoarchean records of the geomagnetic field preserved in the Isua supracrustal belt, southern West Greenland |
| title_fullStr | Possible Eoarchean records of the geomagnetic field preserved in the Isua supracrustal belt, southern West Greenland |
| title_full_unstemmed | Possible Eoarchean records of the geomagnetic field preserved in the Isua supracrustal belt, southern West Greenland |
| title_short | Possible Eoarchean records of the geomagnetic field preserved in the Isua supracrustal belt, southern West Greenland |
| title_sort | possible eoarchean records of the geomagnetic field preserved in the isua supracrustal belt southern west greenland |
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