Ice-contact proglacial lakes associated with the Last Glacial Maximum across the Southern Alps, New Zealand

Sutherland, Jenna L.; Carrivick, Jonathan L.; Shulmeister, James; Quincey, Duncan J.; James, William H.

doi:10.1016/j.quascirev.2019.03.035

Cited by 26 publications

(15 citation statements)

References 120 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Once the Pukaki Glacier became lake terminating, its terminus recession was likely partially decoupled from climate. Such hypotheses have been previously proposed in New Zealand for other glaciers (e.g., Shulmeister et al, 2019; Sutherland, Carrivick, Evans, et al, 2019; Sutherland, Carrivick, Shulmeister, et al, 2019) and have been confirmed for glaciers elsewhere by empirical data, for example, from Patagonia (Bendle et al, 2019). This partial decoupling of glacier behavior from climate is potentially important for interpreting the evolution of New Zealand mountain glaciers, particularly over decadal timescales.…”

Section: Discussionsupporting

confidence: 54%

Proglacial Lakes Control Glacier Geometry and Behavior During Recession

Sutherland

Carrivick

Gandy

et al. 2020

Geophysical Research Letters

View full text Add to dashboard Cite

Ice-contact proglacial lakes are generally absent from numerical model simulations of glacier evolution, and their effects on ice dynamics and on rates of deglaciation remain poorly quantified. Using the BISICLES ice flow model, we analyzed the effects of an ice-contact lake on the Pukaki Glacier, New Zealand, during recession from the Last Glacial Maximum. The ice-contact lake produced a maximum effect on grounding line recession >4 times further and on ice velocities up to 8 times faster, compared to simulations of a land-terminating glacier forced by the same climate. The lake contributed up to 82% of cumulative grounding line recession and 87% of ice velocity during the first 300 years of the simulations, but those values decreased to just 6% and 37%, respectively, after 5,000 years. Numerical models that ignore lake interactions will, therefore, misrepresent the rate of recession especially during the transition of a land-terminating to a lake-terminating environment. Plain Language Summary Lakes form at the margins of glaciers as meltwater accumulates against hillsides and behind ridges of glacier debris. Lakes at a glacier terminus are known to affect its behavior. However, glaciers terminating into such lakes are usually absent from computer simulations, and the effects of these lakes on the rates of deglaciation and on glacier behavior are poorly quantified. In this study, we tested the effect of a lake on glacier recession under two different scenarios; a land-terminating versus a lake-terminating glacier. We used an ice flow model called BISICLES and applied it to what was once the Pukaki Glacier in New Zealand during the end of the last ice age. We found that the presence of a lake caused the glacier to recede more than 4 times further and it accelerated ice flow by up to 8 times when compared to the same glacier that terminated on land under the same climate. Our simulated lake processes predominantly influenced the glacier over decades to centuries rather than over millennia. We suggest, therefore, that simulations of glacier evolution ignoring glacial lakes will likely misrepresent the timing and rate of recession, especially during the transition from a land-terminating to a lake-terminating environment. Recent observations, both field-based (e.g., Watson et al., 2020) and via satellite imagery (e.g., King et al., 2019), have highlighted the spatiotemporal frequency and magnitude of changes in glacial lakes and the associated glaciers that feed meltwater to them. However, field-based measurements are limited to

show abstract

Section: Discussionsupporting

confidence: 54%

Proglacial Lakes Control Glacier Geometry and Behavior During Recession

Sutherland

Carrivick

Gandy

et al. 2020

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…These outwash sediments onlap onto the side of the thrust-block moraine complex in the south of the study area (Figure 4), forming a combined subaerial outwash and thrust-block moraine dam. This combined outwash-head and terminal moraine dam is commonly observed in New Zealand and Icelandic proglacial lakes (e.g., Lake Pukaki and Lake Oahu, Sutherland et al, 2019;Heinabergsjökull, Evans and Orton, 2015). In these lakes, the outwash heads are a sign of sediment-laden meltwater exiting across the ice-sheet margin at many points, allowing outwash fans to build.…”

Section: Stage Four: Large Ice-contact Proglacial Lakementioning

confidence: 82%

“…Ice-rafted debris is found in borehole samples and iceberg scours are present on the lake bed (Figure 7), and the presence of floating ice in the lake is diagnostic of a calving ice-sheet margin (Smith and Ashley, 1985;Thomas and Connell, 1985;Carrivick and Tweed, 2013;Sutherland et al, 2019). The lobate geometry and downlapping stratal terminations of the Lower Lake Dogger sub-unit ( Figure 5) imply a subaqueous outwash fan, with sediment-laden subglacial meltwater plumes fed from subglacial conduits flowing into the lake and depositing the fan, which has then been subject to localized gravitational collapse.…”

Section: Stage Four: Large Ice-contact Proglacial Lakementioning

confidence: 99%

Left High and Dry: Deglaciation of Dogger Bank, North Sea, Recorded in Proglacial Lake Evolution

et al. 2019

Self Cite

View full text Add to dashboard Cite

Reconstructions of palaeo-ice sheet retreat in response to climate warming using offshore archives can provide vital analogs for future ice-sheet behavior. At the Last Glacial Maximum, Dogger Bank, in the southern North Sea, was covered by the Eurasian Ice Sheet. However, the maximum extent and behavior of the ice sheet in the North Sea basin is poorly constrained. We reveal ice-marginal dynamics and maximum ice extent at Dogger Bank through sedimentological and stratigraphic investigation of glacial and proglacial lake sediments. We use a large, integrated subsurface dataset of shallow seismic reflection and geotechnical data collected during windfarm site investigation. For the first time, an ice stream is identified at Dogger Bank, based on preserved subglacial bedforms, eskers and meltwater channels. During ice-sheet advance, a terminal thrustblock moraine complex formed, whose crest runs approximately north-northeast to south-southwest. Subsequent ice stream shutdown caused stagnation of ice, and rapid retreat of the ice-sheet margin. The moraine complex, and outwash head from an adjacent ice-sheet lobe to the west, dammed a large (approximately 750 km 2) proglacial lake. Subsequent sedimentation infilled the lake with 30 m of glacial outwash sediments. A lobate subaqueous fan formed at the ice-sheet margin, which thins toward the southeast with iceberg scours and ice-rafted debris at the base, and is onlapped by lake sediments calibrated to core as alternating clay and silt laminae, interpreted to be varves. The lake became isolated from the retreating ice-sheet margin, and ice-sheet retreat slowed. Sediment-laden meltwater was supplied to the ice-distal proglacial lake for c. 1500-2000 years. Subsequent ice-sheet retreat off Dogger Bank was more rapid due to the negative subglacial slope. The stepped retreat of rapid downwasting, slow retreat, and a final rapid phase off Dogger Bank occurred after the LGM at around 27 ka and before formation of a ribbon lake, dated previously to 23 ka and approximately 60 m lower in elevation, formed to the north of Dogger Bank. The complicated stratigraphic architecture revealed through these data improves forecasting of ground conditions for turbine footings at Dogger Bank, an important step in the provision of clean, sustainable energy.

show abstract

“…Radiocarbon dating of wood excavated from one of the shorelines cut 26 m above the current lake level, suggests the lake was at that level at ~10 ka BP (Bell, 1992). The highest preserved shoreline (~ 50 m above modern lake level, at ~360 m asl), is suggested to have formed at least 1000 years earlier (Bell, 1992, Kober, 1999Thomson, 1996;Sutherland et al, 2019). Other than this, little is known of the absolute timing of prehistorical lake level changes or positions of the Dart River delta.…”

Section: Regional Setting and Site Descriptionmentioning

confidence: 99%