Cryogenic cave carbonate formation during the Industrial Era in the Central Pyrenees (Iberian Peninsula)

Cryogenic cave carbonates (CCC) are rare speleothems that form when water freezes inside cave ice bodies. CCC have been used as an proxy for permafrost degradation, permafrost thickness, or subsurface ice formation. The presence of these minerals is usually attributed to warm periods of permafrost degradation. We found coarse crystalline CCC types within transparent, massive congelation ice in two Pyrenean ice caves in the Monte Perido Massif: Devaux, located on the north face at 2828 m a.s.l., and Sarrios 6, located in the south face at 2780 m a.s.l. The external mean annual air temperature (MAAT) at Devaux is ~ 0&#176;C, while at Sarrios 6 is ~ 2.5&#176;C. In the Monte Perdido massif discontinuous permafrost is currently present between 2750 and 2900 m a.s.l. and is more frequent above 2900 m a.s.l. in northern faces. In Devaux, air and rock temperatures, as well as the presence of hoarfrost and the absence of drip sites indicate a frozen host rock. Moreover, a river flows along the main gallery, and during winters the water freezes at the spring causing backflooding in the cave. In contrast, Sarrios 6 has several drip sites, although the gallery where CCC were collected is hydrologically inactive. This gallery opened in recent years due to ice retreat. During spring, water is present in the gallery due to the overflow of ponds forming beneath drips. CCC commonly formed as sub-millimeter-size spherulites, rhombohedrons and rafts. 230Th ages of the same CCC morphotype indicate that their formation took place at 1953&#177;7, 1959&#177;14, 1957&#177;14, 1958&#177;15, 1974&#177;16 CE in Devaux, while in Sarrios 6 they formed at 1964&#177;5, 1992&#177;2, 1996&#177;1 CE. The cumulative probability density function indicates that the most probable formation occurred 1957-1965 and 1992-1997. The instrumental temperature record at 2860 m a.s.l. indicates positive MAAT in 1964 (0.2&#176;C) and 1997 (0.8&#176;C). CCC formation could thus correspond with those two anomalously warm years. The massive and transparent ice would indicate a sudden ingress of water and subsequent slow freezing inside both caves during those years. Probably, CCC formation took place at a seasonal scale during the annual cycle.

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Holocene climate change, permafrost, and cryogenic carbonate formation: insights from a recently deglaciated, high-elevation cave in the Austrian Alps

Climate of the Past Discussions ◽

10.5194/cpd-10-1493-2014 ◽

2014 ◽

Vol 10 (2) ◽

pp. 1493-1526

Author(s):

C. Spötl ◽

H. Cheng

Keyword(s):

Thermal Structure ◽

High Elevation ◽

Water Infiltration ◽

New Class ◽

Austrian Alps ◽

Carbonate Formation ◽

Discontinuous Permafrost ◽

The Alps ◽

Important Time ◽

Permafrost Thawing

Abstract. Cryogenically formed carbonate particles represent a rather new class of speleothems whose origin is directly linked to the presence of perennial ice in the subsurface. Recent studies concluded that dating these deposits provides important time constraints on the presence and the thickness of permafrost e.g. during the last glacial period. More precisely, these carbonates require the coexistence of water and ice and hence record episodes of permafrost thawing. To shed more light on the origin of the coarsely crystalline variety of these cryogenic cave carbonates – CCCcoarse for short – we examined a high-elevation cave site in the western part of the Austrian Alps which is located in an area dominated by permafrost features and transformed from an ice cave into an essentially ice-free cave during the past decade. Two side chambers of the main gallery revealed cryogenic calcite deposits whose isotopic composition indicates that they formed in individual pools of water carved in ice which underwent very slow freezing under closed-system conditions, i.e. enclosed in ice. 230Th dating shows that most of these carbonates formed ca. 2600 yr BP. Based on comparisons with other palaeoclimate archives in the Alps this thawing episode did not occur during a climate optimum, nor did CCCcoarse form in this cave during e.g. the Roman or the Medieval Warm Periods. Our results suggest that the occurrence of CCCcoarse, at least in mountain regions characterized by discontinuous permafrost, may be more stochastic than previously thought. Given the inherent heterogeneity of karst aquifers and the important role of localized water infiltration in modifying the thermal structure of the subsurface we caution against attributing CCCcoarse occurrences solely to peak warming conditions, while confirming the unique significance of these deposits in providing robust age constraints on permafrost thawing episodes.

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Aeolian mass flux characterization: uncertainties from a wind-tunnel perspective and implications for field studies

10.7287/peerj.preprints.278v1 ◽

2014 ◽

Author(s):

Ate Poortinga ◽

Joep GS Keijsers ◽

Jerry Maroulis ◽

Saskia M. Visser

Keyword(s):

Wind Tunnel ◽

Mass Flux ◽

Shear Velocity ◽

Field Studies ◽

Sediment Traps ◽

Sediment Flux ◽

Cumulative Probability ◽

Surface Moisture ◽

The North ◽

Specific Configuration

Aeolian sediment traps are widely used to estimate the total volume of wind-driven sediment transport, but also to study the vertical mass distribution of a saltating sand cloud. The reliability of sediment flux estimations from this data are dependent upon the specific configuration of the measurement compartments and the analysis approach used. In this study, we analyse the uncertainty of these measurements by investigating the vertical cumulative probability distribution and relative sediment flux derived from both wind-tunnel and field studies. Three existing datasets were used in combination with a newly acquired meteorological dataset, which was collected in combination with sediment fluxes from six different events, using three customized catchers at one of the beaches of Ameland in the north of The Netherlands. Fast-temporal data collected in a wind-tunnel shows that eq has a scattered pattern between impact and fluid threshold, but increases linearly with shear velocities above the fluid threshold. For finer sediment fractions, a larger portion of the sediment was transported closer to the surface compared to coarser sediment fractions. It was also shown that errors originating from the the distribution of the sampling compartments, specifically the location of the lowest sediment trap relative to the surface, can be identified using the relative sediment flux. In the field, surface conditions such as surface moisture, surface crusts or frozen surfaces have a more pronounced, but localized effect, than shear velocity. Uncertainty in aeolian mass flux estimates can be reduced by placing multiple compartments in closer proximity to the surface.

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Taliks: A Tipping Point in Discontinuous Permafrost Degradation in Peatlands

Water Resources Research ◽

10.1029/2018wr024488 ◽

2019 ◽

Vol 55 (11) ◽

pp. 9838-9857 ◽

Cited By ~ 7

Author(s):

Élise G. Devoie ◽

James R. Craig ◽

Ryan F. Connon ◽

William L. Quinton

Keyword(s):

Tipping Point ◽

Permafrost Degradation ◽

Discontinuous Permafrost

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Metallogenetic significance of a North Pennine springwater

Mineralogical Magazine ◽

10.1180/minmag.1990.054.377.16 ◽

1990 ◽

Vol 54 (377) ◽

pp. 629-636 ◽

Cited By ~ 9

Author(s):

D. A. C. Manning ◽

D. W. Strutt

Keyword(s):

Minor Component ◽

Spring Water ◽

Published Data ◽

Significant Component ◽

Sedimentary Sequences ◽

The North ◽

Saline Waters ◽

Saline Spring ◽

Mineralizing Fluids ◽

Mineralizing Potential

AbstractThe occurrence is reported of a saline spring water from Weardale, which compositionally closely resembles other saline waters derived from the Carnmenellis granite, southwest England. The total dissolved solutes achieve approximately 38 000 mg/L, and alkali geothermometers suggest equilibration temperatures of approximately 150°C, equivalent to a depth of 4 km. Using Na, K and Li it is possible to compare the composition of the spring water with those of other spring waters derived from Carboniferous sequences adjacent to the North Pennine Orefield and with published data for fluid inclusions from North Pennine fluorite. These compositional parameters suggest that the ancient mineralizing fluids resemble modern Carboniferous sediment-derived waters and contain a relatively minor component of granite-derived water. Data for Br and Cl indicate that a significant component of the present day Weardale spring waters was probably ultimately derived from organic-rich sedimentary sequences while data for K, Na and Li indicate the importance of a component derived from a permeable granite aquifer. The Weardale springwaters continue to have ‘mineralizing’ potential, in view of the possibility that they may have precipitated quartz or chalcedony during their ascent.

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Impacts of large-scale atmospheric circulation changes due to winter sea-ice retreat on Black Carbon transport and deposition to the Arctic

10.5194/acp-2016-1007 ◽

2016 ◽

Author(s):

Luca Pozzoli ◽

Srdan Dobricic ◽

Simone Russo ◽

Elisabetta Vignati

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

North Atlantic ◽

Large Scale ◽

Southern Oscillation ◽

The Arctic ◽

The North ◽

Ice Retreat ◽

The North Atlantic Oscillation ◽

Sea Ice Retreat

Abstract. Winter warming and sea ice retreat observed in the Arctic in the last decades determine changes of large scale atmospheric circulation pattern that may impact as well the transport of black carbon (BC) to the Arctic and its deposition on the sea ice, with possible feedbacks on the regional and global climate forcing. In this study we developed and applied a new statistical algorithm, based on the Maximum Likelihood Estimate approach, to determine how the changes of three large scale weather patterns (the North Atlantic Oscillation, the Scandinavian Blocking, and the El Nino-Southern Oscillation), associated with winter increasing temperatures and sea ice retreat in the Arctic, impact the transport of BC to the Arctic and its deposition. We found that the three atmospheric patterns together determine a decreasing winter deposition trend of BC between 1980 and 2015 in the Eastern Arctic while they increase BC deposition in the Western Arctic. The increasing trend is mainly due to the more frequent occurrences of stable high pressure systems (atmospheric blocking) near Scandinavia favouring the transport in the lower troposphere of BC from Europe and North Atlantic directly into to the Arctic. The North Atlantic Oscillation has a smaller impact on BC deposition in the Arctic, but determines an increasing BC atmospheric load over the entire Arctic Ocean with increasing BC concentrations in the upper troposphere. The El Nino-Southern Oscillation does not influence significantly the transport and deposition of BC to the Arctic. The results show that changes in atmospheric circulation due to polar atmospheric warming and reduced winter sea ice significantly impacted BC transport and deposition. The anthropogenic emission reductions applied in the last decades were, therefore, crucial to counterbalance the most likely trend of increasing BC pollution in the Arctic.

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Observations on the May 2019 Joffre Peak landslides, British Columbia

Landslides ◽

10.1007/s10346-019-01332-2 ◽

2020 ◽

Vol 17 (4) ◽

pp. 913-930 ◽

Cited By ~ 5

Author(s):

Pierre Friele ◽

Tom H. Millard ◽

Andrew Mitchell ◽

Kate E. Allstadt ◽

Brian Menounos ◽

...

Keyword(s):

British Columbia ◽

Debris Flow ◽

Seismic Analysis ◽

Rock Avalanche ◽

Permafrost Degradation ◽

Depth Estimate ◽

Coast Mountains ◽

Conditioning Factors ◽

The North ◽

Debris Flood

AbstractTwo catastrophic landslides occurred in quick succession on 13 and 16 May 2019, from the north face of Joffre Peak, Cerise Creek, southern Coast Mountains, British Columbia. With headscarps at 2560 m and 2690 m elevation, both began as rock avalanches, rapidly transforming into debris flows along middle Cerise Creek, and finally into debris floods affecting the fan. Beyond the fan margin, a flood surge on Cayoosh Creek reached bankfull and attenuated rapidly downstream; only fine sediment reached Duffey Lake. The toe of the main debris flow deposit reached 4 km from the headscarp, with a travel angle of 0.28, while the debris flood phase reached the fan margin 5.9 km downstream, with a travel angle of 0.22. Photogrammetry indicates the source volume of each event is 2–3 Mm3, with combined volume of 5 Mm3. Lidar differencing, used to assess deposit volume, yielded a similar total result, although error in the depth estimate introduced large volume error masking the expected increase due to dilation and entrainment. The average velocity of the rock avalanche-debris flow phases, from seismic analysis, was ~ 25–30 m/s, and the velocity of the 16 May debris flood on the upper fan, from super-elevation and boulder sizes, was 5–10 m/s. The volume of debris deposited on the fan was ~ 104 m3, 2 orders of magnitude less than the avalanche/debris flow phases. Progressive glacier retreat and permafrost degradation were likely the conditioning factors; precursor rockfall activity was noted at least ~6 months previous; thus, the mountain was primed to fail. The 13 May landslide was apparently triggered by rapid snowmelt, with debuttressing triggering the 16 May event.

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Impacts of permafrost degradation on a road embankment at Umiujaq in Nunavik (Quebec), Canada

Canadian Geotechnical Journal ◽

10.1139/t10-101 ◽

2011 ◽

Vol 48 (5) ◽

pp. 720-740 ◽

Cited By ~ 65

Author(s):

Richard Fortier ◽

Anne-Marie LeBlanc ◽

Wenbing Yu

Keyword(s):

Numerical Modeling ◽

Permafrost Degradation ◽

Sand Layer ◽

Geophysical Investigation ◽

The Road ◽

Access Road ◽

Discontinuous Permafrost ◽

Snow Fence ◽

On The Road ◽

Ground Penetrating

Differential subsidence of as much as 0.85 m is affecting the access road to Umiujaq Airport in Nunavik (Quebec), Canada, located in the discontinuous permafrost zone. A geotechnical and geophysical investigation including piezocone test, ground-penetrating radar profiling, electrical resistivity tomography, and numerical modeling of the thermal regime of the road embankment and subgrade is presented to characterize the ground stratigraphy and permafrost conditions and to assess the exact causes and effects of permafrost degradation on the road embankment. The subsidence is due to thaw consolidation taking place in a layer of ice-rich silt underneath a superficial sand layer. While the seasonal freeze–thaw cycles were initially restricted to the sand layer, the thawing front has now reached the thaw-unstable ice-rich silt layer. According to our numerical modeling, the increase in air temperature recently observed in Nunavik cannot be the sole cause of the observed subsidence affecting this engineering structure. The thick embankment also acts as a snow fence favoring the accumulation of snow on the embankment shoulders. The permafrost degradation is also due to the thermal insulation of the snow cover reducing heat loss in the embankment shoulders and toes.

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“SLIKTRAK”—A COMPUTER SIMULATION OF OFFSHORE OIL SPILLS, CLEANUP, EFFECTS AND ASSOCIATED COSTS

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1977-1-45 ◽

1977 ◽

Vol 1977 (1) ◽

pp. 45-52 ◽

Cited By ~ 3

Author(s):

D. R. Blaikley ◽

G. F. L. Dietzel ◽

A. W. Glass ◽

P. J. van Kleef

Keyword(s):

North Sea ◽

Oil Spills ◽

Oil Pollution ◽

Weather Data ◽

Cumulative Probability ◽

North West ◽

The North ◽

Well Location ◽

The North Sea ◽

Input Variables

ABSTRACT The reasons are introduced for the development of a simulator sufficiently simple to enable weather data normally acquired for E & P operations to be used. “SLIKTRAK,” developed by Shell, applies a slick description and combat concept, developed within the E & P Forum for well blowouts in the North Sea, but applicable to other areas. This concept includes costs for cleanup, damages and the effect of phenomena such as evaporation and natural dispersion. These factors are based on industry experience and vary primarily with sea conditions. The computer programme simulates the continued creation of an oil spill and applies weather data to predict movements of each day's spillage for successive days at sea and quantities of oil left after each day until the oil either disappears or reaches a coastline. Cumulative probability curves for the oil volumes cleaned up, oil arriving at specified shores, total costs, etc., are produced by random selection of input variables such as well location, weather data, the possibility of well bridging etc., and repetition of simulated spill incidents over a large number of cycles. Trace-plots of individual spills may also be generated. In association with the E & P Forum's position as technical advisers to the North West European Civil Liability Convention for Oil Pollution Damage from Offshore Operations, a study based on the North Sea areas has been made. These results and further developments of the program are discussed.

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The impact of wintertime sea-ice retreat on convection in the Nordic Seas

10.5194/egusphere-egu2020-462 ◽

2020 ◽

Author(s):

Yue Wu ◽

David Stevens ◽

Ian Renfrew ◽

Xiaoming Zhai

Keyword(s):

Sea Ice ◽

Temperature Difference ◽

North Atlantic ◽

Nordic Seas ◽

Convective Mixing ◽

The North ◽

Ice Retreat ◽

The North Atlantic ◽

Ice Edge ◽

Sea Ice Retreat

The Nordic Seas have a significant impact on global climate due to their role in providing dense overflows to the North Atlantic Ocean.&#160;However,&#160;the dramatic loss of sea ice in recent decades is creating a new atmosphere-ice-ocean environment where large swathes of the ocean that were previously ice-covered are now exposed to the atmosphere. Despite the largest sea-ice loss occurring in summer and autumn, the sea-ice loss in winter and spring is arguably more important for the climate system. Atmosphere-ocean coupling is the most intense in the extended winter, when convective mixing leads to water-mass modification processes, impacting the densest waters of the Atlantic Meridional Overturning Circulation. Here we focus on the marginal-ice-zone of the Nordic Seas where the air-sea temperature difference is large, promoting high heat flux events during periods of off-ice winds. We use both transient and control simulations of the coupled climate model HiGEM, which allows us to isolate the climate change response from the sea-ice retreat response. We find that wintertime sea-ice retreat leads to remarkable changes in ocean surface heat exchanges and wind energy input. As the sea ice edge retreats towards the Greenland coastline, there is a band of exposed ocean which was previously covered by ice. This exposure allows enhanced mechanical mixing by the wind and a greater loss of buoyancy from the ocean leading to deeper vertical mixing in the upper ocean. Sensible and latent heat fluxes from the ocean to the atmosphere provide the greatest loss of buoyancy. However, climate warming inhibits this process as the atmosphere warms more rapidly than the ocean which reduces the sea-air temperature difference. Further away from the retreating ice edge, toward the centre of the Greenland Sea, the upper ocean warms, resulting in a more stratified water column. As a consequence, the depth of convective mixing reduces over the deep ocean and increases over shallower regions close to the coast. This leads to changes in the formation and properties of some of the water masses that enter the North Atlantic and thus may modify the ocean circulation in the subpolar seas in response to sea-ice decline.&#160;

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