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Becker A.,Rheinstr. 32 | Hauselmann P.,Swiss Institute for Speleology and Karst Studies | Eikenberg J.,Paul Scherrer Institute | Gilli E.,Paris 8 University
International Journal of Speleology | Year: 2012

The present publication focuses on the study of caves in northern and central Switzerland in order to detect and date historical earthquakes and active tectonic displacements by investigations of broken and resealed or displaced speleothems datable by U/Th and 14C. While it can be shown that these methods are potentially suitable, the ages obtained are often beyond the range of historically recorded earthquakes, and it cannot be proved that the observed and dated events are related to a seismic event. Particularly this is true for the caves in central Switzerland, where most ages in the Melchsee-Frutt region were beyond the limits of the U/Th method, or of late Pleistocene age in the Siebenhengste-Hohgant region. A direct comparison with known historical (or prehistoric) earthquakes was not possible. In contrast to central Switzerland, the results in the Basle region of northern Switzerland indicates cave and speleothem damages in one cave within the epicentral area of the 1356 Basle earthquake. 14C datings allowed to directly relate the speleothem damages to this M 6.9 earthquake. Further dating results from caves in northern Switzerland on speleothems and organic material in cave deposits supplied ages which indicate older events not related to the historical Basle earthquake. The detection of active fault displacements and prehistoric strong earthquakes can only be achieved by a very careful deciphering of the palaeo-environmental records and many more age determinations which allow to separate active tectonic displacements and seismic events from other events not related to tectonics, i.e. glaciations, creep of sediments, catastrophic floods etc. Source

Jeannin P.-Y.,Swiss Institute for Speleology and Karst Studies
Boletin Geologico y Minero | Year: 2016

This paper presents an overview of the main karst areas and cave systems in Switzerland. The first part encloses descriptions of the main geological units that hold karst and caves in the country and summarizes a brief history of research and protection of the cave environments. The second part presents three regions enclosing large cave systems. Two regions in the Alps enclose some of the largest limestone caves in Europe: Siebenhengste (Siebenhengste cave system with ~160 km and Bärenschacht with 70 km) and Bödmeren-Silberen (Hölloch cave system with 200 km and Silberen System with 39 km). These systems are also among the deepest with depths ranging between 880 and 1 340 m. The third example is from the Jura Mountains (northern Switzerland). © 2016, Instituto Geologico y Minero de Espana. All rights reserved. Source

Wagner T.,University of Graz | Fabel D.,University of Glasgow | Fiebig M.,University of Natural Resources and Life Sciences, Vienna | Hauselmann P.,Swiss Institute for Speleology and Karst Studies | And 4 more authors.
Earth and Planetary Science Letters | Year: 2010

We report the first incision rates derived from burial ages of cave sediments from the Mur river catchment at the eastern margin of the Eastern Alps. At the transition zone between the Alpine orogen and the Pannonian basin, this river passes through the Paleozoic of Graz - a region of karstifiable rocks called the Central Styrian Karst. This river dissects the study area in a north-south direction and has left behind an abundance of caves. These caves can be grouped into several distinct levels according to their elevation above the present fluvial base level. Age estimates of abandoned cave levels are constrained by dating fluvial sediments washed into caves during the waning stages of speleogenesis with the terrestrial cosmogenic nuclide method. These ages and the elevations of the cave levels relative to the current valley floor are used to infer a very complex history of 4. million. years of water table position, influenced by the entrenchment and aggradation of the Mur river. We observe rather low rates of bedrock incision over the last 4. Ma (in the order of 0.1. mm/y) with an e-folding decrease in this trend to lower rates at younger times. We relate this incision history to a tectonic setting where an increase of drainage area of the Mur river due to stream piracy in Late Miocene to Pliocene times is linked to surface uplift. The later decrease in valley lowering rates is attributed to the rise of the base level related to aggradation of sediments within the valley. Sediment transport through the valley from the upstream section of the Mur river limited the erosional potential of the river to a transport limited state at the later stages of the incision history. © 2010 Elsevier B.V. Source

Blant M.,Swiss Institute for Speleology and Karst Studies | Moretti M.,Swiss Federal Institute of forest | Moretti M.,Bat Protection Center Ticino | Tinner W.,University of Bern
Holocene | Year: 2010

A large-scale palaeozoological study compared 45 14C-dated bat remains from the southern and northern Swiss Alps with palaeovegetational and palaeoclimatic data. Four thermophilous (warm-demanding) and four psychrophilous (cold-tolerant) bat species, mainly forest dwellers, were selected for the study. Myotis blythii is the oldest bat species recorded in the Alps, i.e. on the southern side, going back to the early Holocene at 10 500 cal. BP. Our study showed that thermophilous species (e.g. Myotis bechsteinii and Rhinolophus hipposideros) were most abundant during the Holocene climatic optimum in Central Europe (10 000-4000 cal. BP), when warm-demanding mixed forests were dominant. Psychrophilous species such as Myotis brandtii also occurred during the climatic optimum, but most of the samples fall into the onset of the late Holocene (Sub-Atlantic period), when summer temperatures were already declining. These species declined in the southern Alps after 4000 cal. BP, when fire was intensively used by humans to convert portions of the forest into open land. This fire practice modified forest species composition and structure, with effects on forest-dwelling bat communities. We conclude that during the early and mid Holocene bat community compositions mainly depended on climate and related vegetation and forest structure dynamics. With increasing land use during the mid and late Holocene, anthropogenic changes of forest composition and creation of open habitats increasingly co-determined bat-population dynamics in the Alps. These Swiss findings are in agreement with previous results from eastern Central Europe. © The Author(s) 2010. Source

Affolter S.,University of Bern | Hauselmann A.D.,University of Bern | Fleitmann D.,University of Bern | Fleitmann D.,University of Reading | And 2 more authors.
Quaternary Science Reviews | Year: 2015

Deuterium (δD) and oxygen (δ18O) isotopes are powerful tracers of the hydrological cycle and have been extensively used for paleoclimate reconstructions as they can provide information on past precipitation, temperature and atmospheric circulation. More recently, the use of 17Oexcess derived from precise measurement of δ17O and δ18O gives new and additional insights in tracing the hydrological cycle whereas uncertainties surround this proxy. However, 17Oexcess could provide additional information on the atmospheric conditions at the moisture source as well as about fractionations associated with transport and site processes. In this paper we trace water stable isotopes (δD, δ17O and δ18O) along their path from precipitation to cave drip water and finally to speleothem fluid inclusions for Milandre cave in northwestern Switzerland. A two year-long daily resolved precipitation isotope record close to the cave site is compared to collected cave drip water (3 months average resolution) and fluid inclusions of modern and Holocene stalagmites. Amount weighted mean δD, δ18O and δ17O are -71.0‰, -9.9‰, -5.2‰ for precipitation, -60.3‰, -8.7‰, -4.6‰ for cave drip water and -61.3‰, -8.3‰, -4.7‰ for recent fluid inclusions respectively. Second order parameters have also been derived in precipitation and drip water and present similar values with 18 per meg for 17Oexcess whereas d-excess is 1.5‰ more negative in drip water. Furthermore, the atmospheric signal is shifted towards enriched values in the drip water and fluid inclusions (δ of ~ + 10‰ for δD). The isotopic composition of cave drip water exhibits a weak seasonal signal which is shifted by around 8-10 months (groundwater residence time) when compared to the precipitation. Moreover, we carried out the first δ17O measurement in speleothem fluid inclusions, as well as the first comparison of the δ17O behaviour from the meteoric water to the fluid inclusions entrapment in speleothems. This study on precipitation, drip water and fluid inclusions will be used as a speleothem proxy calibration for Milandre cave in order to reconstruct paleotemperatures and moisture source variations for Western Central Europe. © 2015 Elsevier Ltd. Source

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