Discovery of distal ejecta from the 1850 Ma Sudbury Impact Event
A 25?70-cm-thick, laterally correlative layer near the contact between the Paleoproterozoic sedimentary Gunflint Iron Formation and overlying Rove Formation and between the Biwabik Iron Formation and overlying Virginia Formation, western Lake Superior region, contains shocked quartz and feldspar gra...
| Main Authors: | , , , , , , , |
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| Format: | Journal Article |
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Geological Society of America Inc
2005
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11937/43900 |
| _version_ | 1848756841817833472 |
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| author | Addison, W. Brumpton, G. Vallini, D. Davis, D. Kissin, S. Fralick, P. McNaughton, Neal Hammond, A. |
| author_facet | Addison, W. Brumpton, G. Vallini, D. Davis, D. Kissin, S. Fralick, P. McNaughton, Neal Hammond, A. |
| author_sort | Addison, W. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | A 25?70-cm-thick, laterally correlative layer near the contact between the Paleoproterozoic sedimentary Gunflint Iron Formation and overlying Rove Formation and between the Biwabik Iron Formation and overlying Virginia Formation, western Lake Superior region, contains shocked quartz and feldspar grains found within accretionary lapilli, accreted grain clusters, and spherule masses, demonstrating that the layer contains hypervelocity impact ejecta. Zircon geochronologic data from tuffaceous horizons bracketing the layer reveal that it formed between ca. 1878 Ma and 1836 Ma. The Sudbury impact event, which occurred 650?875 km to the east at 1850 1 Ma, is therefore the likely ejecta source, making these the oldest ejecta linked to a specific impact. Shock features, particularly planar deformation features, are remarkably well preserved in localized zones within the ejecta, whereas in other zones, mineral replacement, primarily carbonate, has significantly altered or destroyed ejecta features. |
| first_indexed | 2025-11-14T09:18:37Z |
| format | Journal Article |
| id | curtin-20.500.11937-43900 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:18:37Z |
| publishDate | 2005 |
| publisher | Geological Society of America Inc |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-439002017-09-13T16:00:10Z Discovery of distal ejecta from the 1850 Ma Sudbury Impact Event Addison, W. Brumpton, G. Vallini, D. Davis, D. Kissin, S. Fralick, P. McNaughton, Neal Hammond, A. precise U-Pb dates Minnesota Gunflint and Biwabik Formations distal ejecta Sudbury impactite Ontario A 25?70-cm-thick, laterally correlative layer near the contact between the Paleoproterozoic sedimentary Gunflint Iron Formation and overlying Rove Formation and between the Biwabik Iron Formation and overlying Virginia Formation, western Lake Superior region, contains shocked quartz and feldspar grains found within accretionary lapilli, accreted grain clusters, and spherule masses, demonstrating that the layer contains hypervelocity impact ejecta. Zircon geochronologic data from tuffaceous horizons bracketing the layer reveal that it formed between ca. 1878 Ma and 1836 Ma. The Sudbury impact event, which occurred 650?875 km to the east at 1850 1 Ma, is therefore the likely ejecta source, making these the oldest ejecta linked to a specific impact. Shock features, particularly planar deformation features, are remarkably well preserved in localized zones within the ejecta, whereas in other zones, mineral replacement, primarily carbonate, has significantly altered or destroyed ejecta features. 2005 Journal Article http://hdl.handle.net/20.500.11937/43900 10.1130/G21048.1 Geological Society of America Inc restricted |
| spellingShingle | precise U-Pb dates Minnesota Gunflint and Biwabik Formations distal ejecta Sudbury impactite Ontario Addison, W. Brumpton, G. Vallini, D. Davis, D. Kissin, S. Fralick, P. McNaughton, Neal Hammond, A. Discovery of distal ejecta from the 1850 Ma Sudbury Impact Event |
| title | Discovery of distal ejecta from the 1850 Ma Sudbury Impact Event |
| title_full | Discovery of distal ejecta from the 1850 Ma Sudbury Impact Event |
| title_fullStr | Discovery of distal ejecta from the 1850 Ma Sudbury Impact Event |
| title_full_unstemmed | Discovery of distal ejecta from the 1850 Ma Sudbury Impact Event |
| title_short | Discovery of distal ejecta from the 1850 Ma Sudbury Impact Event |
| title_sort | discovery of distal ejecta from the 1850 ma sudbury impact event |
| topic | precise U-Pb dates Minnesota Gunflint and Biwabik Formations distal ejecta Sudbury impactite Ontario |
| url | http://hdl.handle.net/20.500.11937/43900 |