Formation of a large ice depression on Dålk Glacier (Larsemann Hills, East Antarctica) caused by the rapid drainage of an englacial cavity

Боронина, Алина Сергеевна; Попов, С. В.; Pryakhina, Galina; Chetverova, Antonina; Ryzhova, Ekaterina; Григорьева, С. Д.

doi:10.1017/jog.2021.58

Cited by 16 publications

(8 citation statements)

References 42 publications

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“…10). Elsewhere in Antarctica, a 183 m × 220 m depression bounded by ice cliffs has been described in the Larsemann Hills (East Antarctica), although in this case the collapse of the overlying ice was caused by drainage of supraglacial water and nearby epiglacial lakes into an englacial cavity in 2017 causing its overfill and outburst (Boronina et al, 2021).…”

Section: Evidence Elsewhere In Antarcticamentioning

confidence: 99%

Drainage and refill of an Antarctic Peninsula subglacial lake reveal an active subglacial hydrological network

et al. 2022

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Abstract. The presence of subglacial lakes and subglacial hydrological networks under the East and West Antarctic ice sheets is now relatively well understood, whilst their influence on ice dynamics is the subject of ongoing research. In contrast, little is known about subglacial lakes and hydrological networks under the Antarctic Peninsula Ice Sheet and how these are influencing glacier behaviour. Here we describe the rapid drainage and slow refill of a subglacial lake under Mars Glacier using remote sensing and aerogeophysics. Results suggest drainage of the subglacial lake occurred prior to 2011, resulting in the collapse of the overlying ice into the newly formed subglacial cavity. The cavity has been refilling since this time, with peak rates of infilling associated with seasonal surface meltwater activity. We review evidence for similar features elsewhere in the Antarctic Peninsula and discuss whether their appearance marks a threshold shift in glacier thermal regimes and the activation or enhancement of their subglacial hydrological networks by surface meltwater. Collectively, these features show coupling of climate processes and the bed of the region's glaciers highlighting their ongoing vulnerability to climate change.

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Section: Evidence Elsewhere In Antarcticamentioning

confidence: 99%

Drainage and refill of an Antarctic Peninsula subglacial lake reveal an active subglacial hydrological network

et al. 2022

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“…Besides, an intense swarm of high-frequency events near the end of December are anomalous (Figure 4). This swarm coincided with the drainage of the lake near the Russian Progress-3 Station beginning on 8 Jan 2020 and the following overflow of neighboring lakes (Boronina et al, 2021). This seems to imply that the high-frequency events can also be caused by instability changes in the nearby glacial systems.…”

Section: Mechanisms Of Short-duration Broadband Events: Surface Therm...mentioning

confidence: 64%

Environment-modulated glacial seismicity near Dalk Glacier in East Antarctica revealed by deep clustering

et al. 2023

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East Antarctica constitutes two-thirds of the Antarctic continent, where glacier systems have been thought to be more stable than those in West Antarctica. However, the stability could be increasingly undermined by global warming, intensifying local and regional glacial activities. Here, using deep unsupervised learning, we analyze seismic signals recorded by a dense nodal array near Dalk glacier in the Larsemann Hills, East Antarctica, in austral summer (6 Dec 2019 – 2 Jan 2020). We apply an autoencoder to automatically extract event features and input them to a Gaussian mixture model for clustering. During the operation period, three main types of seismic signals are identified: high-frequency monochromatic events, broadband short-duration icequakes, and low-frequency long-duration events. By comparing these events to environmental observations (local wind speed, temperature, tide level, and satellite imagery), we infer that the first type was wind-induced vibration, the second type thermal contraction/basal slip, and the third type water-filled crevassing/iceberg calving. The latter two glacial activities appear to be modulated by temperature and tide, respectively, implying the susceptibility of Dalk glacier to environment conditions in East Antarctica. Our results demonstrate that deep clustering is an effective means to identify diverse glacial seismicity and contributes to the rapid growth of passive glacier seismic monitoring.

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“…The apparent recent appearance of similar features 926 km further south on Alexander Island at the PICS and Callisto Cliffs may indicate the southward expression of this phase of glacier response to regional warming (at or before 2013). At the same time, analysis of flow rates of glaciers feeding George VI Ice Shelf have shown a c. 15% mean acceleration of, relative to their time-averaged baselines (Boxall et al, 2022), consistent with the activation of their subglacial hydrological networks. Similar accelerations have been described in Icelandic 255 glaciers following subglacial floods (Magnússon et al, 2007).…”

Section: Wider Implicationsmentioning

confidence: 82%

“…The identification of active subglacial hydrological networks as far south as southern Alexander Island suggests 260 a coupling of surface climate processes and the bed, and helps explain the strong seasonality seen in glacier flow rates during the annual melt season (Boxall et al, 2022). This can be attributed to an increase in basal water pressure, enhancing basal motion (Tuckett et al, 2019) and increased coupling between supraglacial and basal hydrology.…”

Section: Wider Implicationsmentioning

confidence: 92%

“…10). Elsewhere, a 183 m × 220 m depression bounded by ice cliffs has been described in the Larsemann Hills, East Antarctica; although in this 235 case the collapse of the overlying ice was caused by drainage of supraglacial water and nearby epiglacial lakes into an englacial cavity in 2017 causing its overfill and outburst (Boronina et al, 2021).…”

Section: Evidence Elsewherementioning

confidence: 99%

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Drainage and refill of an Antarctic Peninsula subglacial lake reveals an active subglacial hydrological network

Hodgson

Jordan²,

Riley³

et al. 2022

Preprint

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Abstract. The role of subglacial hydrological networks and subglacial lakes in modulating ice dynamics under the East and West Antarctic Ice Sheets is now relatively well understood. In contrast, little is known about subglacial water bodies under the Antarctic Peninsula Ice Sheet and how these are influencing glacier behaviour. Here we describe the rapid drainage and slow refill of a subglacial lake under Mars Glacier using remote sensing and aerogeophysics platforms. Results suggest drainage of the subglacial lake occurred prior to 2013, resulting in collapse of the overlying ice into the newly formed subglacial cavity. The lake has been refiling since this time, with peak rates of infilling associated with seasonal meltwater activity. We review evidence for similar features elsewhere in the Antarctic Peninsula and discuss whether their appearance marks a threshold shift in the thermal regime of the region’s glaciers and the activation of their subglacial hydrological networks. Collectively, these features show coupling of surface climate processes and the bed and may help explain the strong seasonality seen in glacier flow rates during the annual melt season and the ongoing regional decline in ice mass.

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Formation of a large ice depression on Dålk Glacier (Larsemann Hills, East Antarctica) caused by the rapid drainage of an englacial cavity

Cited by 16 publications

References 42 publications

Drainage and refill of an Antarctic Peninsula subglacial lake reveal an active subglacial hydrological network

Drainage and refill of an Antarctic Peninsula subglacial lake reveal an active subglacial hydrological network

Environment-modulated glacial seismicity near Dalk Glacier in East Antarctica revealed by deep clustering

Drainage and refill of an Antarctic Peninsula subglacial lake reveals an active subglacial hydrological network

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