| Titre | The palynological record of lake sediments and their application to paleoseismology |
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| Auteur | McCarthy, F M G; Alderson, A; Pilkington, P M; Brooks, G R ; Boyce, J I |
| Source | GSA 2020 Connects Online; Geological Society of America, Abstracts With Programs vol. 52, no. 6, 165-7, 2020 p. 1, https://doi.org/10.1130/abs/2020AM-352383 |
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| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20210416 |
| Éditeur | Geological Society of America |
| Réunion | Geological Society of America Annual Meeting 2020; Octobre 25-28, 2020 |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1130/abs/2020AM-352383 |
| Media | numérique; en ligne |
| Formats | html; pdf |
| Sujets | palynologie; palynomorphes; pollen; sediments lacustres; sismicité; risque sismique; secousses séismiques; risque de tremblement de terre; antecedents de sedimentation; fossiles; glissements de terrain;
mouvement de masse; dépôts de glissement de terrain; seiches; gyttja; analyses stratigraphiques; sédiments lacustres; dépôts de versants; paléontologie; géologie des dépôts meubles/géomorphologie; stratigraphie; Sciences et technologie; Nature et
environnement; Santé et sécurité; Phanérozoïque; Cénozoïque; Quaternaire |
| Programme | Géoscience pour la sécurité publique Société de gestion des déchets nucléaires |
| Diffusé | 2020 10 01 |
| Résumé | (disponible en anglais seulement)
Eastern North America is an intraplate region characterized by potentially damaging earthquakes with long recurrence intervals. Seismic risk, however, is
difficult to assess because of short historic records, and there are few confirmed post-glacial faults. The abundant lakes in the region are natural archives of post-glacial sedimentation. The deep basins of lakes are typically comprised primarily of
organic matter fixed by aquatic algae and their consumers, with small quantities of biogenic carbonates or silica and aeolian mineral particles disseminated in gyttja. Analysis of historic seismic events has shown that sudden increases in
allochthonous sediments (together with fossils of terrestrial and shoreline origin in deep-water sediments) characterize sudden-onset events such as mass transport and seiches. The acid-resistant component of sediments (both the identifiable remains
of organisms, i.e., palynomorphs, and the particulate and amorphous organic matter that constitute the palynofacies) can reflect the sudden influx of allochthonous materials to deep lake basins. Regional pollen stratigraphies allow the ages of these
sudden influxes to be estimated, and if coeval events can be identified in multiple lakes, a common regional-scale trigger - such as paleoseismicity - can be inferred, extending the record beyond the relatively short historic period in eastern North
America. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Les organismes microscopiques échantillonnés pour les carottes extraites du fond des lacs peuvent être étudiés pour aider à identifier
l'occurrence de tremblements de terre préhistoriques. Ce résumé résume une présentation sur la façon dont cela a été fait. |
| GEOSCAN ID | 329261 |
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