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Université de Fribourg

Palynological study of carbonated mounds during the holocene along the atlantic and mediterranean moroccan margins

Rachid, Jihad ; Hssaida, Touria ; Hamoumi, Naima ; Terhzaz, Loubna ; Spezzaferri, Silvia ; Frank, Norbert ; Daghor, Lamia

In: Review of Palaeobotany and Palynology, 2020, vol. 278, p. 104213

A palynological study of carbonate mounds of Atlantic and Mediterranean Moroccan margins was conducted on sediment boxcores MD13-3441, MD13-3456, MD13-3461, MD13-3465, MD13-3468 collected during the oceanographic cruise MD 194/Eurofleet - GATEWAY, which took place on June 2013.The organic remaining revealed a dominance of dinoflagellate cysts over the continental fraction, which showed very...

Université de Fribourg

Estimating glacier-bed overdeepenings as possible sites of future lakes in the de-glaciating Mont Blanc massif (Western European Alps)

Magnin, F. ; Haeberli, W. ; Linsbauer, Andreas ; Deline, P. ; Ravanel, L.

In: Geomorphology, 2020, vol. 350, p. 106913

De-glaciating high mountain areas result in new landscapes of bedrock and debris where permafrost can degrade, persist or even newly form in cases, and of new lakes in glacier bed overdeepenings (GBOs) becoming ice-free. These landscapes with new lakes in close neighborhood to over-steepened and perennially frozen slopes are prone to chain reaction processes (e.g. rock-ice avalanches into...

Université de Fribourg

Foraminiferal-based biotic indices to assess the ecological quality status of the Gulf of Gabes (Tunisia): Present limitations and future perspectives

Kateb, Akram El ; Stalder, Claudio ; Martínez-Colón, Michael ; Mateu-Vicens, Guillem ; Francescangeli, Fabio ; Coletti, Giovanni ; Stainbank, Stephanie ; Spezzaferri, Silvia

In: Ecological Indicators, 2020, vol. 111, p. 105962

Biotic indices are tools to assess the ecological status of marine systems, and can be based on different metrics (such as ecological groups, specific diversity). The present study applies five biotic indices based on living (stained) benthic foraminiferal assemblages to assess ecological conditions in a wide area of the Mediterranean Sea in the heavily polluted Gulf of Gabes and along the...

Université de Fribourg

Potential future lakes from continued glacier shrinkage in the Aosta Valley Region (Western Alps, Italy)

Viani, Cristina ; Machguth, Horst ; Huggel, Christian ; Godio, Alberto ; Franco, Diego ; Perotti, Luigi ; Giardino, Marco

In: Geomorphology, 2020, vol. 355, p. 107068

Aosta Valley (Western Alps, Italy) is the region with the largest glacierized area of Italy. Like other high mountain regions, it has shown a significant glacier retreat starting from the end of the ‘Little Ice Age’ that is expected to continue in the future. As a direct consequence of glacier shrinkage, glacier-bed overdeepenings become exposed, offering suitable geomorphological ...

Université de Fribourg

Direct observations of a three million cubic meter rock-slope collapse with almost immediate initiation of ensuing debris flows

Walter, Fabian ; Amann, Florian ; Kos, Andrew ; Kenner, Robert ; Phillips, Marcia ; Preux, Antoine de ; Huss, Matthias ; Tognacca, Christian ; Clinton, John ; Diehl, Tobias ; Bonanomi, Yves

In: Geomorphology, 2020, vol. 351, p. 106933

Catastrophic collapse of large rock slopes ranks as one of the most hazardous natural phenomena in mountain landscapes. The cascade of events, from rock- slope failure, to rock avalanche and the near-immediate release of debris flows has not previously been described from direct observations. We report on the 2017, 3.0 × 106 m3 failure on Pizzo Cengalo in Switzerland, which led to human...

Université de Fribourg

Petrophysical joint inversion applied to alpine permafrost field sites to image subsurface ice, water, air, and rock contents

Mollaret, Coline ; Wagner, Florian M. ; Hilbich, Christin ; Scapozza, Cristian ; Hauck, Christian

In: Frontiers in Earth Sc-ience, 2020, vol. 8, p. -

Quantification of ground ice is crucial for understanding permafrost systems and modeling their ongoing degradation. The volumetric ice content is however rarely estimated in permafrost studies, as it is particularly difficult to retrieve. Standard borehole temperature monitoring is unable to provide any ice content estimation, whereas non-invasive geophysical techniques, such as refraction ...

Université de Fribourg

Detailed detection of active layer freeze-thaw dynamics using quasi-continuous electrical resistivity tomography (Deception Island, Antarctica)

Farzamian, Mohammad ; Vieira, Gonçalo ; Santos, Fernando A. Monteiro ; Tabar, Borhan Yaghoobi ; Hauck, Christian ; Paz, Maria Catarina ; Bernardo, Ivo ; Ramos, Miguel ; Pablo, Miguel Angel de

In: The Cryosphere, 2020, vol. 14, no. 3, p. 1105–1120

Climate-induced warming of permafrost soils is a global phenomenon, with regional and site-specific variations which are not fully understood. In this context, a 2-D automated electrical resistivity tomography (A-ERT) system was installed for the first time in Antarctica at Deception Island, associated to the existing Crater Lake site of the Circumpolar Active Layer Monitoring – South ...

Université de Fribourg

Assessing the potential of soil moisture measurements for regional landslide early warning

Wicki, Adrian ; Lehmann, Peter ; Hauck, Christian ; Seneviratne, Sonia I. ; Waldner, Peter ; Stähli, Manfred

In: Landslides, 2020, p. -

In mountainous terrain, rainfall-induced landslides pose a serious risk to people and infrastructure. Regional landslide early warning systems (LEWS) have proven to be a cost-efficient tool to inform the public about the imminent landslide danger. While most operational LEWS are based on rainfall exceedance thresholds only, recent studies have demonstrated an improvement of the forecast...

Université de Fribourg

Impact of bottom water currents on benthic foraminiferal assemblages in a cold-water coral environment: The Moira Mounds (NE Atlantic)

Fentimen, Robin ; Lim, Aaron ; Rüggeberg, Andres ; Wheeler, Andrew J. ; Rooij, David Van ; Foubert, Anneleen

In: Marine Micropaleontology, 2020, vol. 154, p. 101799

Strong bottom currents play a key role in cold-water coral environments by shaping their morphology and providing the necessary food for the corals to thrive. This study investigates the differences between living and dead benthic foraminiferal assemblages in such environments, more precisely on the Moira Mounds (NE Atlantic). A specific focus is to understand the role of currents and their...

Université de Fribourg

Monitoring rock glacier kinematics with satellite synthetic aperture radar

Strozzi, Tazio ; Caduff, Rafael ; Jones, Nina ; Barboux, Chloé ; Delaloye, Reynald ; Bodin, Xavier ; Kääb, Andreas ; Mätzler, Eva ; Schrott, Lothar

In: Remote Sensing, 2020, vol. 12, no. 3, p. 559

Active rock glaciers represent the best visual expression of mountain permafrost that can be mapped and monitored directly using remotely sensed data. Active rock glaciers are bodies that consist of a perennially frozen ice/rock mixture and express a distinct flow-like morphology indicating downslope permafrost creep movement. Annual rates of motion have ranged from a few millimeters to...