Preprints
Filtering by Subject: Glaciology
Distributed Acoustic Sensing of Microseismic Sources and Wave Propagation in Glaciated Terrain
Published: 2020-01-09
Subjects: Earth Sciences, Environmental Sciences, Glaciology, Physical Sciences and Mathematics
Records of Alpine microseismicity are a powerful tool to study landscape-shaping processes and warn against hazardous mass movements. Unfortunately, seismic sensor coverage in Alpine regions is typically insufficient. Here we show that distributed acoustic sensing (DAS) bridges critical observational gaps of seismogenic processes in Alpine terrain. Dynamic strain measurements in a 1 km long fiber [...]
Artificial and natural radionuclides in cryoconite as tracers of supraglacial dynamics
Published: 2020-01-02
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Cryoconite, a sediment found on the surface of glaciers, is known for its ability to accumulate radionuclides. New data on cryoconite from the Morteratsch glacier (Switzerland) are presented with the aim to shed light on the mechanisms that control the distribution of radioactivity in cryoconite. Among the many radionuclides detected in our samples, we have identified 108mAg, an artificial [...]
A Speed Limit on Ice Shelf Collapse through Hydrofracture
Published: 2019-10-30
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Increasing surface melt has been implicated in the collapse of several Antarctic ice shelves over the last few decades, including the collapse of Larsen B Ice Shelf over a period of just a few weeks in 2002. The speed at which an ice shelf disintegrates strongly determines the subsequent loss of grounded ice and sea level rise, but the controls on collapse speed are not well understood. Here we [...]
PYRENAIC ROCK GLACIERS: AN AIRBORNE AND MULTITEMPORAL LiDAR MONITORING CASE STUDY IN THE BESIBERRI AREA
Published: 2019-10-24
Subjects: Earth Sciences, Environmental Sciences, Geology, Geomorphology, Glaciology, Physical Sciences and Mathematics
The monitoring of rock glaciers is a current subject of interest because of its application as permafrost indicator and its sensitivity to climatic changes (especially temperature and precipitation). Alpine rock glaciers in the Pyrenees have been described by various authors, but to study them regionally has been a challenge since most of these studies are based on ground-based techniques. Two [...]
Investigating potential icequakes at Llaima volcano, Chile
Published: 2019-10-24
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics, Volcanology
Glacially- and magmatically-derived seismic events have been noted to heavily overlap in characteristics, thus there exists the potential for false-alarms or missed warnings at ice-covered volcanoes. Here we present the first study to specifically target icequakes at an ice-covered volcano in Southern Chile. Two months of broadband seismic data collected at Llaima volcano in 2015 were analyzed in [...]
Holocene relative sea-level changes and glacial isostatic adjustment of the U.S. Atlantic coast
Published: 2019-09-30
Subjects: Climate, Earth Sciences, Environmental Sciences, Geomorphology, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
The first quality-controlled Holocene sea-level database for the U.S. Atlantic coast has been constructed from 686 sea-level indicators. The database documents a decreasing rate of relative sea-level (RSL) rise through time with no evidence of sea level being above present in the middle to late Holocene. The highest rates of RSL rise are found in the mid-Atlantic region. We employ the database to [...]
Collapse of Eurasian ice sheets 14,600 years ago was a major source of global Meltwater Pulse 1a
Published: 2019-08-21
Subjects: Climate, Earth Sciences, Environmental Sciences, Geology, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Rapid sea-level rise caused by the collapse of large ice sheets is a global threat to human societies. In the last deglacial period, the rate of global sea-level rise peaked at more than 4 cm/yr during Meltwater Pulse 1a, which coincided with the abrupt Bølling warming event 14,650 yr ago. However, the sources of the meltwater have proven elusive, and the contribution from Eurasian ice sheets has [...]
Frozen fringe explains sediment freeze-on during Heinrich events
Published: 2019-08-16
Subjects: Applied Mathematics, Earth Sciences, Glaciology, Physical Sciences and Mathematics
Anomalous coarse-grained sediment layers beneath the North Atlantic likely originated from sediment freeze-on to the base of ice sheets during the last glacial period. These layers represent periods of extreme ice discharge, called Heinrich events, and are variously attributed to ice stream flow instability, ice shelf collapse, or enhanced terminus melting due to ocean warming. In this paper, we [...]
Climatic patterns over the European Alps during the LGM derived from inversion of the paleo-ice extent
Published: 2019-08-07
Subjects: Earth Sciences, Geomorphology, Glaciology, Physical Sciences and Mathematics
The Quaternary climate has been dominated by alternating glacial and interglacial periods. While the timing and extent of past ice caps are well documented, local variations in temperature and precipitation as a response to cyclic glaciations are not resolved. Resolving these issues is necessary for understanding regional and global climate circulation. In particular, how did the cold [...]
Basal melting over Subglacial Lake Ellsworth and it catchment: insights from englacial layering
Published: 2019-07-25
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Hydrology, Physical Sciences and Mathematics
Deep-water ‘stable’ subglacial lakes likely contain microbial life adapted in isolation to extreme environmental conditions. How water is supplied into a subglacial lake, and how water outflows, is important for understanding these conditions. Isochronal radio-echo layers have been used to infer where melting occurs above Lake Vostok and Lake Concordia in East Antarctica but have not been used [...]
The Glacial Origins of Relict Pingos, Wales, UK
Published: 2019-07-04
Subjects: Earth Sciences, Geomorphology, Glaciology, Physical Sciences and Mathematics
Ramparted depressions (doughnut-shaped debris-cored ridges with peat- and/or sediment-filled central basins) are commonly perceived to represent the relict collapsed forms of permafrost ground-ice mounds (i.e. pingos or lithalsas). In Wales, UK, ramparted depressions of Late Pleistocene age have been widely attributed to permafrost-related processes. However, a variety of alternative glacial [...]
Amplified Last-Glacial-Maximum response of Chandra valley (western Himalaya) glaciers
Published: 2019-06-03
Subjects: Earth Sciences, Geomorphology, Glaciology, Physical Sciences and Mathematics
Geomorphological evidence suggests a subdued response of Himalayan glaciers during the Last Glacial Maximum (LGM), with relatively minor advances (~10 km) reported in several glacierised valleys across the region. This supports the hypothesis that a weakened Indian summer monsoon during the LGM largely counterbalanced the effects of a colder climate on Himalayan glaciers. In contrast, a recently [...]
Glacier area and the variability of glacier change
Published: 2019-05-31
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
This is the preprint of a letter that is under review in the Journal of Glaciology. The abstract is as follows: Large-scale remote-sensing data on ice loss in the Himalaya and other glacierised regions indicate that the differences in glacier area do not significantly influence the glacier-to-glacier variability of the thinning rate. An analysis of the available data from several regions across [...]
Estimation of the total sub-debris ablation from point-scale ablation data on a debris-covered glacier
Published: 2019-05-31
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
This is the preprint of an article that is under review in the Journal of Glaciology. The abstract is as follows: Glaciological mass balance is computed from point-scale field data at a few ablation stakes that are regressed as a function of elevation, and averaged over the area-elevation distribution of the glacier. This method is contingent on a tight control of elevation on local ablation. On [...]
Marine biomarkers from ice cores reveal enhanced high-latitude Southern Ocean carbon sink during the Antarctic Cold Reversal
Published: 2019-05-31
Subjects: Biogeochemistry, Earth Sciences, Glaciology, Paleontology, Physical Sciences and Mathematics
Determining the feedbacks that modulate Southern Ocean carbon dynamics is key to understanding past and future climate. The global pause in rising atmospheric CO2 during the period of mid- to high-latitude southern surface cooling known as the Antarctic Cold Reversal (ACR, 14,700-12,700 years ago) provides an opportunity to disentangle competing influences. We present highly-resolved and [...]