A Paleozoic age for the Tunnunik impact structure

Camille Lepaulard, Jérôme Gattacceca, Nicholas Swanson-Hysell, Yoann Quesnel, François Demory, Gordon R. Osinski

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

We report paleomagnetic directions from the target rocks of the Tunnunik impact structure, as well as from lithic impact breccia dikes that formed during the impact event. The target sedimentary rocks have been remagnetized after impact-related tilting during a reverse polarity interval. Their magnetization is unblocked up to 350 °C. The diabase dikes intruding into these sediments retained their original magnetization which unblocks above 400 °C. The impact breccia records a paleomagnetic direction similar to that of the overprints in the target sedimentary rocks. The comparison of the resulting virtual geomagnetic pole for the Tunnunik impact structure with the apparent polar wander path for Laurentia combined with biostratigraphic constraints from the target sedimentary rocks is most consistent with an impact age in the Late Ordovician or Silurian, around 430–450 Ma, soon after the deposition of the youngest impacted sedimentary rocks. Our results from the overprinted sedimentary rocks and diabase dikes imply that the postimpact temperature of the studied rocks was about 350 °C.

Original languageEnglish (US)
Pages (from-to)740-751
Number of pages12
JournalMeteoritics and Planetary Science
Volume54
Issue number4
DOIs
StatePublished - Apr 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© The Meteoritical Society, 2019.

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