The subglacial origin of the Lake Agassiz–Ojibway final outburst flood

Lajeunesse, Patrick; St‐Onge, Guillaume

doi:10.1038/ngeo130

Cited by 94 publications

(69 citation statements)

References 23 publications

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“…The increase in the meridional (latitudinal) temperature gradient leads to stronger westerly winds in the mid-latitudes and strengthened winter wind speed above the northwestern China (Sun et al, 2012). Our δ 13 C and Ba/Ca records reflect a deteriorated climate initiated at 8.42 ka BP, agreeing well with the timing of the draining of glacial lakes Agassiz and Ojibway through the Hudson Bay into the North Atlantic (8.42 ± 0.30 ka BP; Barber et al, 1999;Kleiven et al, 2008;Lajeunesse and St-Onge, 2008). The culminated episode centred at ∼ 8.20 ka BP is very consistent with the timing, duration and structure of the 8.2 ka event in the GISP2 record.…”

Section: Monsoonal 82 Ka Eventsupporting

confidence: 71%

Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the "8.2 ka event"

Wang

Cheng

et al. 2012

Clim. Past

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Abstract. The prominent "8.2 ka event" was well documented in the Greenland ice cores. It remains unclear, however, about its duration, structure and forcing mechanism at low-to mid-latitude regions. Here we use the physical and geochemical data of stalagmites from the Nuanhe Cave in Liaoning Province, northeastern China, to reconstruct a detailed history of East Asian monsoons covering the entire duration of the event. High-resolution chronologies of two contemporaneous stalagmites, each consisting of at least 770 yr annual growth bands, were established by calibrating and anchoring the floating band-counting ages against five highprecision 230 Th dates. Two oxygen isotope profiles replicate each other on annual-decadal timescales despite their difference in growth rates, indicating that the δ 18 O variability has a climatic origin largely associated with changes in the rainfall δ 18 O from the West Pacific during summer season. A signal from the "8.2ka event" was faint in our δ 18 O records, not as significant as Indian monsoon dominated stalagmite δ 18 O records from Qunf in Oman and Dongge in Southern China. However, our δ 13 C and Ba/Ca profiles, as indicators of local environmental changes, provide strong support for a climate reversal centred at 8.2 ka BP, which is likely controlled by winter monsoon circulations via the westerly winds associated with North Atlantic climate. Therefore, we concluded that the winter-and summer-Asian monsoons responded independently to the high northern latitude climate.

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Section: Monsoonal 82 Ka Eventsupporting

confidence: 71%

Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the "8.2 ka event"

Wang

Cheng

et al. 2012

Clim. Past

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“…Lake Agassiz appears to have drained in several flood events of relatively short duration, but with an estimated total discharge into the Labrador Sea of ca. 151 400 km 3 (Andrews et al, 1995Clarke et al, 2004Clarke et al, , 2009Ellison et al, 2006;Hillaire-Marcel et al, 2007;Kerwin, 1996;Lajeunesse and St-Onge, 2008;Lewis et al, 2012;Roy et al, 2011). The background flux is smaller (ca.…”

Section: Freshwater Forcingmentioning

confidence: 99%

The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

et al. 2017

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Abstract. Two interglacial epochs are included in the suite of Paleoclimate Modeling Intercomparison Project (PMIP4) simulations in the Coupled Model Intercomparison Project (CMIP6). The experimental protocols for simulations of the mid-Holocene (midHolocene, 6000 years before present) and the Last Interglacial (lig127k, 127 000 years before present) are described here. These equilibrium simulations are designed to examine the impact of changes in orbital forcing at times when atmospheric greenhouse gas levels were similar to those of the preindustrial period and the continental configurations were almost identical to modern ones. These simulations test our understanding of the interplay between radiative forcing and atmospheric circulation, and the connections among large-scale and regional climate changes giving rise to phenomena such as land-sea contrast and highlatitude amplification in temperature changes, and responses of the monsoons, as compared to today. They also provide an opportunity, through carefully designed additional sensitivity experiments, to quantify the strength of atmosphere, ocean, cryosphere, and land-surface feedbacks. Sensitivity experiments are proposed to investigate the role of freshwater forcing in triggering abrupt climate changes within interglacial epochs. These feedback experiments naturally lead to a focus on climate evolution during interglacial periods, which will be examined through transient experiments. Analyses of the sensitivity simulations will also focus on interactions between extratropical and tropical circulation, and the relationship between changes in mean climate state and climate variability on annual to multi-decadal timescales. The comparative abundance of paleoenvironmental data and of quantitative climate reconstructions for the Holocene and Last Interglacial make these two epochs ideal candidates for systematic evaluation of model performance, and such comparisons will shed new light on the importance of external feedbacks (e.g., vegetation, dust) and the ability of state-of-the-art models to simulate climate changes realistically.

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“…After all, in the period around the 8.2 ka climate event the ice-dam that blocked the Laurentide Lakes (Fig. 2) disappeared fast, according to reconstructions by Dyke (2004) within a period of 200 years, and increased ice-rafted debris (IRD) concentrations and iceberg scours suggest increased iceberg activity in this period (Bond et al 1997(Bond et al , 2001Moros et al 2004;Josenhans and Zevenhuizen 1990;Lajeunesse and St-Onge 2008;Jakobsson 2008).…”

Section: Introductionmentioning

confidence: 99%

A role for icebergs in the 8.2 ka climate event

Wiersma

Jongma

2009

Clim Dyn

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We investigate the potential role of icebergs in the 8.2 ka climate event, using a coupled climate model equipped with an iceberg component. First, we evaluate the effect of a large iceberg discharge originating from the decaying Laurentide ice sheet on ocean circulation, compared to a release of an identical volume of freshwater alone. Our results show that, on top of the freshwater effect, a large iceberg discharge facilitates sea-ice growth as a result of lower sea-surface temperatures induced by latent heat of melting. This causes an 8% increased sea-ice cover, 5% stronger reduction in North Atlantic Deep Water production and 1°C lower temperature in Greenland. Second, we use the model to investigate the effect of a hypothetical two-stage lake drainage, which is suggested by several investigators to have triggered the 8.2 ka climate event. To account for the final collapse of the ice-dam holding the Laurentide Lakes we accompany the secondary freshwater pulse in one scenario with a fast 5-year iceberg discharge and in a second scenario with a slow 100-year iceberg discharge. Our experiments show that a two-stage lake drainage accompanied by the collapsing ice-dam could explain the anomalies observed around the 8.2 ka climate event in various climate records. In addition, they advocate a potential role for icebergs in the 8.2 ka climate event and illustrate the importance of latent heat of melting in the simulation of climate events that involve icebergs. Our two-stage lake drainage experiments provide a framework in the discussion of two-stage lake drainage and ice sheet collapse.

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The subglacial origin of the Lake Agassiz–Ojibway final outburst flood

Cited by 94 publications

References 23 publications

Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the "8.2 ka event"

Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the "8.2 ka event"

The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

A role for icebergs in the 8.2 ka climate event

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The subglacial origin of the Lake Agassiz–Ojibway final outburst flood

Cited by 94 publications

References 23 publications

Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the &quot;8.2 ka event&quot;

Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the &quot;8.2 ka event&quot;

The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

A role for icebergs in the 8.2 ka climate event

Contact Info

Product

Resources

About

Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the "8.2 ka event"

Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the "8.2 ka event"