Late glacial and Holocene sedimentary environments of Quesnel Lake, British Columbia

Gilbert, Robert G.; Desloges, Joseph R.

doi:10.1016/j.geomorph.2012.08.010

Cited by 18 publications

(22 citation statements)

References 39 publications

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“…12C and 13D), the LIS margin might have become disconnected with the Pentecôte glaciolacustrine basin, leading to sediment supply essentially controlled by a glaciofluvial outwash plain confined in the axis of the valley with a delta that prograded into the lake. The accumulation rates of 4 cm a −1 (inferred from the 4 cm laminae couplet thickness) to 0.63 cm a −1 are similar to those observed in present-day glacial lakes in the Canadian Cordillera and Patagonia Gilbert, 1995, 1998;Gilbert and Desloges, 2012;Van Daele et al, 2016), depending on the influence and distance of glacial Fig. 9.…”

Section: Lake Pentecôtesupporting

confidence: 74%

Late-Quaternary glacial to postglacial sedimentation in three adjacent fjord-lakes of the Québec North Shore (eastern Canadian Shield)

Poiré

Lajeunesse

Normandeau

et al. 2018

Quaternary Science Reviews

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High-resolution swath bathymetry imagery allowed mapping in great detail the sublacustrine geomorphology of lakes Pentecôte, Walker and Pasteur, three deep adjacent fjord-lakes of the Québec North Shore (eastern Canada). These sedimentary basins have been glacio-isostatically uplifted to form deep steep-sided elongated lakes. Their key geographical position and limnogeological characteristics typical of fjords suggest exceptional potential for long-term high-resolution paleoenvironmental reconstitutions. Acoustic subbottom profiles acquired using a bi-frequency Chirp echosounder (3.5 & 12 kHz), together with cm-and m-long sediment core data, reveal the presence of four acoustic stratigraphic units. The acoustic basement (Unit 1) represents the structural bedrock and/or the ice-contact sediments of the Laurentide Ice Sheet and reveals V-shaped bedrock valleys at the bottom of the lakes occupied by ice-loaded sediments in a basin-fill geometry (Unit 2). Moraines observed at the bottom of lakes and in their structural valleys indicate a deglaciation punctuated by short-term ice margin stabilizations. Following ice retreat and their isolation, the fjord-lakes were filled by a thick draping sequence of rhythmically laminated silts and clays (Unit 3) deposited during glaciomarine and/or glaciolacustrine settings. These sediments were episodically disturbed by mass-movements during deglaciation due to glacial-isostatic rebound. AMS 14 C dating reveal that the transition between deglaciation of the lakes Pentecôte and Walker watersheds and the development of para-and post-glacial conditions occurred around 8000 cal BP. The development of the lake-head river delta plain during the Holocene provided a constant source of fluvial sediment supply to the lakes and the formation of turbidity current bedforms on the sublacustrine delta slopes. The upper sediment succession (i.e., ∼4-∼6.5 m) consists of a continuous para-to post-glacial sediment drape (Unit 4) that contains laminated and massive sediment and series of Rapidly Deposited Layers. These results allow establishing a conceptual model of how a glaciated coastal fjord develops during and after deglaciation in a context of rapid glacio-isostatically forced regression.

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Section: Lake Pentecôtesupporting

confidence: 74%

Late-Quaternary glacial to postglacial sedimentation in three adjacent fjord-lakes of the Québec North Shore (eastern Canadian Shield)

Poiré

Lajeunesse

Normandeau

et al. 2018

Quaternary Science Reviews

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“…Natural lake sediments are a heterogeneous mix of organic matter, biota, and mineral phases that come both from autochthonous and allochthonous sources, that are constantly deposited and buried 5–8 . Natural lake sediments host highly abundant and active microbial communities spanning all three domains of life.…”

Section: Introductionmentioning

confidence: 99%

The bacterial community of Quesnel Lake sediments impacted by a catastrophic mine tailings spill differ in composition from those at undisturbed locations – two years post-spill

Hatam

Petticrew

French

et al. 2019

Sci Rep

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The West Basin of Quesnel Lake (British Columbia, Canada) suffered a catastrophic disturbance event in August 2014 when mine tailings and scoured natural material were deposited into the lake’s West Basin due to an impoundment failure at the adjacent Mount Polley copper-gold mine. The deposit covered a significant portion of the West Basin floor with a thick layer of material. Since lake sediments host bacterial communities that play key roles in the geochemical cycling in lacustrine environments, it is important to understand which groups inhabit the newly deposited material and what this implies for the ecological function of the West Basin. Here we report a study conducted two years post-spill, comparing the bacterial communities from sediments of both disturbed and undisturbed sites. Our results show that sediments from disturbed sites differed in physical and chemical properties than those in undisturbed sites (e.g. higher pH, particle size and Cu concentration). Furthermore, bacterial communities from the disturbed sites appeared to be legacy communities from the tailings impoundment, with metabolic potential revolving mainly around the cycling of S and metals, whereas the ones from the undisturbed sites were associated with the cycling of N.

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“…The discharged water and tailings from the breach event flowed down and scoured Hazeltine Creek and entered Quesnel Lake midway along the West Basin. Figures b and c indicate the amount of overburden transported to the lake from the creek's watershed, which was predominantly forested and underlain by Quaternary glaciolacustrine sediment [ Gilbert and Desloges , ].…”

Section: Introductionmentioning

confidence: 99%

The impact of a catastrophic mine tailings impoundment spill into one of North America's largest fjord lakes: Quesnel Lake, British Columbia, Canada

Petticrew

Albers

Baldwin

et al. 2015

Geophysical Research Letters

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On 4 August 2014, a catastrophic breach of the Mount Polley mine tailings impoundment released ~25 M m3 of tailings and water and scoured an unknown quantity of overburden into the West Basin of Quesnel Lake. We document Quesnel Lake and Quesnel River observations for 2 months postspill. Breach inflows raised Quesnel Lake by 7.7 cm, equivalent to ~21 M m3. The West Basin hypolimnion was modified immediately, exhibiting increased temperature (~5°C to 6–7.5°C), conductivity (110 to 160 μS/cm), and turbidity (<1 to 200–1000 nephelometric turbidity units (NTU)). Cooscillating seiches moved West Basin hypolimnetic water both westward and eastward contaminating the Main Basin. Postspill, high‐turbidity water propagated eastward (~1 cm/s), introducing a persistent ~20 m thick layer below the thermocline and an ~30 m thick layer at the bottom. The contaminant introduction, mobilization, and bioaccumulation may pose risks to resident and anadromous fish stocks, which support recreational, commercial, and First Nations fisheries.

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Late glacial and Holocene sedimentary environments of Quesnel Lake, British Columbia

Cited by 18 publications

References 39 publications

Late-Quaternary glacial to postglacial sedimentation in three adjacent fjord-lakes of the Québec North Shore (eastern Canadian Shield)

Late-Quaternary glacial to postglacial sedimentation in three adjacent fjord-lakes of the Québec North Shore (eastern Canadian Shield)

The bacterial community of Quesnel Lake sediments impacted by a catastrophic mine tailings spill differ in composition from those at undisturbed locations – two years post-spill

The impact of a catastrophic mine tailings impoundment spill into one of North America's largest fjord lakes: Quesnel Lake, British Columbia, Canada

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