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Université de Fribourg

Decrypting silicic magma/plug fragmentation at Azufral crater lake, Northern Andes : insights from fine to extremely fine ash morpho-chemistry

Pardo, Natalia ; Avellaneda, Jose D. ; Rausch, Juanita ; Jaramillo-Vogel, David ; Gutiérrez, Mariana ; Foubert, Anneleen

In: Bulletin of Volcanology, 2020, vol. 82, no. 12, p. 79

Azufral (SW Colombia) is a dangerous silicic volcano hosting a crater lake, which serves as an excellent example of an incipient plug disruption through phreatomagmatism. We studied the youngest succession of dilute pyroclastic density currents (PDCs) onlapping the north-eastern crater rim. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy was used to carry out an...

Université de Fribourg

A general theory of rock glacier creep based on in-situ and remote sensing observations

Cicoira, Alessandro ; Marcer, Marco ; Gärtner‐Roer, Isabelle ; Bodin, Xavier ; Arenson, Lukas U. ; Vieli, Andreas

In: Permafrost and Periglacial Processes, 2020, vol. 32, no. 1, p. 139-153

The ongoing acceleration in rock glacier velocities concurrent with increasing air temperatures, and the widespread onset of rock glacier destabilization have reinforced the interest in rock glacier dynamics and in its coupling to the climate system. Despite the increasing number of studies investigating this phenomenon, our knowledge of both the fundamental mechanisms controlling rock...

Université de Fribourg

Geochemical fingerprinting of key lithologies and depositional processes across the upper boundary of the Opalinus Clay (Aalenian, Middle Jurassic, northern Switzerland)

Lauper, Bruno ; Deplazes, Gaudenz ; Vogel, Hendrik ; Jaeggi, David ; Wohlwend, Stephan ; Ariztegui, Daniel ; Foubert, Anneleen

In: The Depositional Record, 2021, vol. 7, no. 1, p. 25-51

The Opalinus Clay is an argillaceous to silty mudstone formation, notable in Switzerland as the selected host rock for deep geological disposal of radioactive waste. Its upper bounding unit (Passwang Formation and eastern equivalents) is composed of successions of mudstone, sandy bioclastic marl and limestone separated by ooidal ironstone beds. The lithostratigraphic transition is diachronous...

Université de Fribourg

Geomorphic response to the lateglacial–holocene transition in high alpine regions (Sanetsch pass, Swiss alps)

Serra, Elena ; Valla, Pierre G. ; Gribenski, Natacha ; Guedes Magrani, Fabio ; Carcaillet, Julien ; Delaloye, Reynald ; Grobéty, Bernard ; Braillard, Luc

In: Boreas, 2020, p. bor.12480

Several palaeoclimatic archives have documented the pronounced climatic and environmental change associated with the Lateglacial–Holocene transition in the European Alps. However, the geomorphic response to this major environmental transition has only been punctually investigated. In this study, we propose a detailed reconstruction of post‐Last Glacial Maximum palaeoenvironmental...

Université de Fribourg

Twenty years of European mountain permafrost dynamics—the PACE legacy

Etzelmüller, Bernd ; Guglielmin, Mauro ; Hauck, Christian ; Hilbich, Christin ; Hoelzle, Martin ; Isaksen, Ketil ; Noetzli, Jeanette ; Oliva, Marc ; Ramos, Miguel

In: Environmental Research Letters, 2020, vol. 15, no. 10, p. 104070

This paper reviews and analyses the past 20 years of change and variability of European mountain permafrost in response to climate change based on time series of ground temperatures along a south–north transect of deep boreholes from Sierra Nevada in Spain (37°N) to Svalbard (78°N), established between 1998 and 2000 during the EU-funded PACE (Permafrost and Climate in Europe) project. In...

Université de Fribourg

Anthropogenic climate change and glacier lake outburst flood risk: local and global drivers and responsibilities for the case of lake Palcacocha, Peru

Huggel, Christian ; Carey, Mark ; Emmer, Adam ; Frey, Holger ; Walker-Crawford, Noah ; Wallimann-Helmer, Ivo

In: Natural Hazards and Earth System Sciences, 2020, vol. 20, no. 8, p. 2175–2193

Evidence of observed negative impacts on natural and human systems from anthropogenic climate change is increasing. However, human systems in particular are dynamic and influenced by multiple drivers and hence identifying an anthropogenic climate signal is challenging. Here we analyze the case of lake Palcacocha in the Andes of Peru, which offers a representative model for other glacier lakes...

Université de Fribourg

Spatial and temporal analysis of meso- and microplastic pollution in the Ligurian and Tyrrhenian Seas

Caldwell, Jessica ; Muff, Livius F. ; Pham, Christopher K. ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara ; Lehner, Roman

In: Marine Pollution Bulletin, 2020, vol. 159, p. 111515

Areas like the Mediterranean coastlines, which have high population density, represent locations of high pollution risk for surrounding environments. Thus, this study aims to compare data on the abundance, size, and composition of buoyant plastic particles collected during two weeks in 2019 in the Ligurian and Tyrrhenian Seas with data from 2018. The results from 2019 show average meso- and ...

Université de Fribourg

Early diagenetic imprint on temperature proxies in holocene corals: a case study from french polynesia

Rashid, Rashid ; Eisenhauer, Anton ; Liebetrau, Volker ; Fietzke, Jan ; Böhm, Florian ; Wall, Marlene ; Krause, Stefan ; Rüggeberg, Andres ; Dullo, Wolf-Christian ; Jurikova, Hana ; Samankassou, Elias ; Lazar, Boaz

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

Coral-based reconstructions of sea surface temperatures (SSTs) using Sr/Ca, U/Ca and δ18O ratios are important tools for quantitative analysis of past climate variabilities. However, post-depositional alteration of coral aragonite, particularly early diagenesis, restrict the accuracy of calibrated proxies even on young corals. Considering the diagenetic effects, we present new Mid to Late...

Université de Fribourg

Geodynamics, seismicity, and seismic hazards of the Caucasus

Ismail-Zadeh, Alik ; Adamia, Shota ; Chabukiani, Aleksandre ; Chelidze, Tamaz ; Cloetingh, Sierd ; Floyd, Michael ; Gorshkov, Alexander ; Gvishiani, Alexei ; Ismail-Zadeh, Tahir ; Kabanh, Mikhail K. ; Kadirov, Fakhraddin ; Karapetyan, Jon ; Kangarli, Talat ; Kiria, Jemal ; Koulakov, Ivan ; Mosar, Jon ; Mumladze, Tea ; Müller, Birgit ; Sadradze, Nino ; Safarov, Rafig ; Schilling, Frank ; Soloviev, Alexander

In: Earth-Science Reviews, 2020, vol. 207, p. 103222

Being a part of ongoing continental collision between the Arabian and Eurasian plates, the Caucasus region is a remarkable site of moderate to strong seismicity, where devastating earthquakes caused significant losses of lives and livelihood. In this article, we survey geology and geodynamics of the Caucasus and its surroundings; magmatism and heat flow; active tectonics and tectonic stresses...