| Titre | Evidence of early postglacial paleoearthquakes from lakes in northeastern Ontario-western Quebec, Canada |
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| Auteur | Brooks, G R |
| Source | GSA 2020 Connects Online - Geological Society of America Annual Meeting; Geological Society of America, Abstracts With Programs vol. 52, no. 6, 2020 p. 1, https://doi.org/10.1130/abs/2020AM-354630 |
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| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200300 |
| Éditeur | Geological Society of America |
| Réunion | GSA 2020: Geological Society of America Annual Meeting 2020; Octobre 26-30, 2020 |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1130/abs/2020AM-354630 |
| Media | en ligne; numérique |
| Formats | html; pdf |
| Province | Ontario; Québec |
| SNRC | 31M/06; 31M/07; 31M/08; 31M/09; 31M/10; 31M/11; 31M/15; 31M/16; 31N/05; 31N/12; 31N/13; 32C/04; 32C/05; 32C/12; 32C/13; 32D; 41O/08; 41O/09; 41O/16; 41P/05; 41P/06; 41P/07; 41P/08; 41P/09; 41P/10; 41P/11;
41P/12; 41P/13; 41P/14; 41P/15; 41P/16; 42A; 42B/01; 42B/08; 42B/09; 42B/16 |
| Région | Kirkland Lake; Rouyn-Noranda; Dasserat Lake; Dufresnoy Lake; Duparquet Lake; Chassignolle Lake; Malartic Lake |
| Lat/Long OENS | -82.4167 -77.8333 49.0000 47.2500 |
| Sujets | glissements de terrain; mouvement de masse; dépôts de glissement de terrain; secousses séismiques; sismicité; antecedents glaciaires; déglaciation; lacs glaciaires; relèvement isostatique; débit de
sedimentation; sediments lacustres; varves; analyses stratigraphiques; Lac glaciaire d'Ojibway; sédiments glaciolacustres; géologie des dépôts meubles/géomorphologie; stratigraphie; Nature et environnement; Sciences et technologie; Phanérozoïque;
Cénozoïque; Quaternaire |
| Programme | Géoscience pour la sécurité publique Société de gestion des déchets nucléaires |
| Diffusé | 2020 10 01 |
| Résumé | (disponible en anglais seulement)
Glacial Lake Ojibway was a large glacial lake in northeastern Ontario-western Quebec that persisted roughly between 10.57-8.47 ka cal BP, and experienced high
rates of glaciolacustrine sedimentation. Mass transport deposits (MTDs) buried at differing stratigraphic levels within the glaciolacustrine sediments are ubiquitous throughout the region. Detailed mapping of the sub-bottom deposits at Dasserat,
Duparquet, and Dufresnoy lakes, located 24 to 38 km apart, near Rouyn-Noranda, Quebec, produced 26 MTD event horizons of which 15 contain three or more MTDs. High-resolution, relative dating control from varves indicates: that the event horizons span
a period of ~450 years (between about 9.4-8.95 ka cal BP); that one set of identically-aged event horizons is common to each lake; and another set is common to two lakes. The 15 event horizons containing three or more MTDs are interpreted to be
evidence of 11 paleoearthquakes of magnitude about Mw5 or larger. The confidence of each interpretation is weighted from low to high, reflecting the relative strength of the MTD signature in each event horizon (moderate (three to five MTDs) or strong
(more than six)), and evidence of common- or similar-aged MTD signatures at two or more distinctly-separate locations. The event horizon with the most numerous and widespread MTDs in each lake occurred in the identical varve year 1483 (~9.1 ka cal
BP). These event horizons are part of a regional MTD signature present in other lakes and in subaerial exposures across at least 220 km of northeastern Ontario and western Quebec. This signature is interpreted to be best explained by a
paleoearthquake of ~Mw7.3. The interpreted paleoearthquakes occurred at a time when early postglacial uplift had diminished moderately, but was still high, compared to mid-Holocene and late Holocene rates. The record, thus, is likely representative
of a period of elevated, early postglacial, seismicity associated with rapid crustal unloading. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cette présentation résume un enregistrement reconstitué d'anciens tremblements de terre qui se sont produits dans le nord-est de l'Ontario et
l'ouest du Québec. L'enregistrement est basé sur la cartographie et la datation des dépôts de glissements de terrain conservés dans les lits des lacs de la région. |
| GEOSCAN ID | 326914 |
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