Jura Mountains Research Articles

Controls on the stable Mo isotopic composition of inner-continental precipitation

The molybdenum (Mo) isotope budget of the surface environment has been well characterized in recent decades, facilitating accurate mass balance modeling of the ancient redox-driven Mo cycle. One yet unresolved component is the range of possible processes and sources that result in isotopically heavy river waters relative to continental sources. Following a recent hypothesis that isotopically heavy δ98Mo of precipitation may control the final δ98Mo of river water relative to its continental source bedrock, we investigated the δ98Mo composition of 19 snow samples from three locations in Central Europe: the Swiss Alps (“Alpine” samples) from the Hochalpine Forschungsstation Jungfraujoch (HFSJ) in both summer and winter, the Swiss Jura Mountains in winter and the French Vosges Mountains in winter. Stream waters from two snowmelt-fed streams were additionally collected from the Alpine site. Snow sample δ98Mo compositions were highly variable, ranging from −0.03 to +1.93 ‰, with no clear mixing trends indicating complex sources, source pathways, or post-depositional processing. Only the winter snow samples from the high-altitude HFSJ site had δ98Mo values consistently heavier than typical continental crust. The δ98Mo results were coupled with radiogenic Sr isotopic, major ion, and trace element compositions as tracers for three major sources of airborne ion inputs: sea salt, mineral dust, and anthropogenic aerosols. We found that the most likely source of Mo to precipitation in the lower elevation Vosges and Jura Mountains samples was isotopically light soil mineral dust, which reflected the underlying bedrock sources, with a likely additional anthropogenic component. The isotopically heavy winter snow samples at the elevated HFSJ site were attributed to a higher input of carbonate mineral dust from long-distance transport of carbonate-rich Saharan dust, which was overwritten in the summer by an influx of low elevation sources transported upwards during higher vertical thermal mixing. Finally, we concluded that precipitation has a negligible direct effect on the overall Mo content and isotopic composition of inner continental European streams and rivers relative to other sources, such as bedrock weathering. Future time-series studies may augment these conclusions to show possible heterogeneity of precipitation as well as the addition of sample sites closer to marine sources, where a larger flux of isotopically heavy marine aerosols to streams might be expected.

Denudation and Weathering Rates of Carbonate Landscapes From Meteoric 10Be/9Be Ratios

AbstractKnowledge of the rates of carbonate rock denudation, the relative apportionment of chemical weathering versus physical erosion, and their sensitivity to climate, vegetation, and tectonics is essential for disclosing feedbacks within the carbon cycle and the functioning of karst landscapes that supply important services to humans. Currently, however, for carbonate lithologies, no method exists that allows to simultaneously partition denudation into erosion and weathering fluxes at spatial scales ranging from soil to watersheds. To determine total denudation rates in carbonate landscapes from an individual soil or river sample, we adapted a published framework that combines cosmogenic meteoric 10Be as an atmospheric flux tracer with stable 9Be that is released from rocks by weathering, to the limestone‐dominated French Jura Mountains. By analyzing water, soil, sediment, travertine, and bedrock for 10Be/9Be, major and trace elements, carbon stable isotopes and radiogenic strontium, we quantified contributions of Be from primary versus secondary carbonate phases and its release during weathering from carbonate bedrock versus silicate impurities. We calculated partitioning of Be between solids and solutes, and rates of catchment‐wide (from sediment) and point source (from soil) denudation, weathering and erosion. Our results indicate that average denudation rates are 300–500 t/km2/yr. Denudation is dominated by weathering intensity (W/D) ratios of >0.92, and a non‐negligible contribution from deeper (below soil) weathering. Our rates agree to within less than a factor of two with decadal‐scale denudation rates from combined suspended and dissolved fluxes, highlighting the substantial potential of this method for future Earth surface studies.

Composition and diversity of ground beetles within wooded pastures and alternative land-use systems in Swiss Jura mountains

AbstractWooded pastures combine trees and pastures in a land-use system resulting from traditional silvopastoral practices. With their sparse tree cover, wooded pastures represent an ecotone between open area pastures and forests with potentially high species diversity, although this is poorly tested for animal groups especially insects. In this study, we aimed to characterise and compare species communities in terms of species composition and diversity indices, biomass and ecological traits of ground beetles in wooded pastures, forests and non-wooded pastures. Pitfall traps were set up in 29 study sites located in the Swiss Jura mountains. Ground beetle communities in wooded pastures largely encompass those in open pastures and forests, although some species are found only in forests or open areas. Wooded pastures and open pastures have an equivalent species diversity level, which is significantly higher than the one in forests. Ground beetle diversity is positively correlated with the surfaces of Biodiversity Promotion Areas within a 100 m radius. Areas with high tree cover (70–100%) favour brachypterous and hygrophilic species, whereas areas with reduced tree cover (0–20%) favour xerophilic and winged species. Ground beetles’ size and biomass increase with tree cover. Wooded pastures are an important ecotone, ensuring a gradual change of land-use systems between open areas and forests, where a wide range of species from both land-use systems are found. These semi-natural systems are important for the conservation of ground beetles.

Discovery of the world longest known intra-till cave (Jura mountains, France): Age and formation processes

We describe an atypical cave network in the Jura mountains (eastern France), currently the only one known worldwide to be entirely excavated within a subglacial deposits. Extending over 600 m of mapped galleries, this natural cavity developed entirely within a large impermeable drumlin shaped during last glacial stage MIS 2 (Wurm). By using lidar topography, petrophysical, sedimentological and geochemical measurements, as well as U-Th dating, this cave is mainly attributed to mechanical erosion processes (piping cave). The network's morphogenesis seems to be characterized by two main phases. Firstly, thin mini-pipes were probably dug along shear planes previously formed within the drumlin. The first mini-pipes may have appeared under the ice cover during the last glaciation in response to differential hydraulic pressures on either side of the drumlin. They may also have appeared later when the drumlin was free from its glacial cover, forming a natural earth dam across a thalweg and obstructing the flow of surface water. A second phase would correspond to the development of mega-pipes, resulting from sequential capture of flows from mini-pipes. Mega-pipes appeared >2500 years ago, as indicated by U-Th dating of one speleothem. In other regions of the world, intra-till caves have been documented, but are <20 m long. This limitation is mainly attributed to instability of the materials constituting subglacial tills, disfavoring a durable existence of galleries without collapses. In the Jura calcareous mountains the subglacial till contains a high proportion of very fine calcite matrix produced by subglacial abrasion, which was indurated by compaction under several hundred meters of ice. These particular petrographic features appear to be required for the creation and the preservation of this long intra-till cave. Similar caves may likely be found in other regions of the world displaying limestone bedrock and where subglacial till with abundant carbonate matrix was formed.

Response to ‘Improving abundance estimation by combining capture–recapture and presence–absence data: Example with a large carnivore’

Abstract A key area of research in ecological statistics involves combining data sources from multiple streams to improve population estimates. One such model attempts to integrate capture–recapture and presence–absence data to estimate the population size of Eurasian lynx in the Jura Mountains, eastern France. This model has been observed to underestimate population sizes. We conducted an extensive simulation study to evaluate the model's performance. We describe our methods for generation of simultaneous capture–recapture and presence–absence data and demonstrate that the model is flawed. Finally, we give an outline of our hypothesis on why the model underestimates population sizes.

Interaction between basement inherited strike-slip structures and thrust wedge propagation in the Northern Tianshan foreland basin: insight from analogue modelling experiments

Basement inherited structures represent a significant factor affecting thrust propagation dynamics during the growth of fold-and-thrust belts. In this study inspirited from seismic data analysis of Gaoquan anticline in the Northern Tianshan foreland basin, we devised an experimental approach to investigate the structural and kinematical evolution of deformation from preexisting basement restraining bend to subsequent contractional deformation. Tested parameters included reactivation of the basement restraining bend and erosion. Results indicated that when preexisting basement restraining bend was reactivated and folded an overlying décollement, subsequent thrust nucleated preferentially at the top of the folded décollement. Erosion helped localize deformation, thereby reducing the width of the deformation zone and promoting “out-of-sequence” thrusting during compression. Finally, as we employed silicone polymer to simulate overpressured mudstone layer in the major décollement, our experiments also provide insights into a better understanding of the relationship between shallow salt-detached thrusting and deep inherited basement structures, such as in the Jura Mountains structures.

A hybrid physics-based and data-driven model for intra-day and day-ahead wind power forecasting considering a drastically expanded predictor search space

This work presents a novel hybrid (physics- and data-driven) model for short-term (intra-day and day-ahead, 3h-24h) wind power forecasting (STWPF). Traditionally, STWPF predictors admitted very few meteorological variables only from the grid points closest to the turbines. Here, with the aim to further capture the underlying atmospheric processes ruling the wind variability in the wind farm, the approach relies on drastically expanding the predictor space, composed of numerous meteorological variables throughout a large geographical domain, retrieved from a weather forecasting model (COSMO-1). An ad-hoc genetic algorithm that optimizes the selection of predictors is designed and combined with feed-forward artificial neural networks for its cost function evaluation. The introduced model is compared to multiple benchmark models in a 16-turbine wind farm in the Swiss Jura mountains. For +12h and +24h lead times, the new approach shows a root-mean squared error normalized to the installed wind farm capacity of 11% and 11.6%, respectively. These values entail ∼16% higher forecasting skill compared to state-of-the-art predictor frameworks. Results highlight the ability of the presented approach to systematically select as predictors different variables with a well-known impact on the wind farm performance, such as the turbulent kinetic energy or the vertical wind shear. Clustering the data according to the wind direction provides substantial benefit. In addition, it provides a better understanding of the attained improvement: largest performances occur in those wind directions affected by highly complex terrain. This indicates that the proposed model can be especially suitable for wind farms in complex terrain.

Combining geological and archaeological evidence to infer the recent tectonics of the Montagne du Vuache Fault, Jura Mountains, France

Combining geological and archaeological evidence to infer the recent tectonics of the Montagne du Vuache Fault, Jura Mountains, France

Reconstructing the Evolution of Foreland Fold‐And‐Thrust Belts Using U‐Pb Calcite Dating: An Integrated Case‐Study From the Easternmost Jura Mountains (Switzerland)

AbstractThis case‐study from the Jura Mountains in the foreland of the European Alps demonstrates how the coupling of subsurface analysis and U‐Pb carbonate dating can provide absolute timing constraints and shortening rate estimates of fold‐and‐thrust belts. It is confirmed that the initial Late Cenozoic foreland deformation driving the formation of the easternmost Jura Mountains in Switzerland was predominately thin‐skinned with contractional deformation largely restricted to the Mesozoic succession above a sub‐horizontal basal décollement. Thereby, the localization and structural style of related deformation structures was strongly guided by the characteristics of underlying Late Paleozoic half grabens. The main thin‐skinned thrust front formed at ∼12 Ma, followed by further deformation in the hinterland and locally continued foreland‐directed thrust propagation. The major deformation zones exposed at surface were established at ∼8 Ma but shortening continued until at least ∼4 Ma. Thick‐skinned contraction associated with the inversion of basement structures only played a subordinate role during the latest deformation phase after 8 Ma. Based on cumulative shortening values derived from balanced cross sections, our U‐Pb ages of syn‐tectonic calcite slickenfibres allow to estimate thin‐skinned deformation rates for the easternmost Jura Mountains between ∼0.9 and ∼0.1 mm/year, decreasing toward the eastern tip of the arcuate belt. Moreover, deformation rates seemingly decreased over time with rates of initial thin‐skinned thrusting being significantly higher than the later deformation north of the main thrust front. These new findings from a classical foreland setting highlight the potential of integrating U‐Pb dating in regional fold‐and‐thrust belt investigations elsewhere.

Impacts of climate warming, pollution, and management on the vegetation composition of Central European beech forests

Over the past century, climate warming, nitrogen deposition, acidic rain, widespread disturbance events, adaptive management, and natural stand maturation have substantially altered the composition and structure of forests. However, the absence of historical data on the environment makes it difficult to prove these long-term effects. Ecological indicator values based on plant species characteristics offer a promising approach to detect presumed changes at relevant spatial scales (i.e., site level). In this study, we discerned the shifts in taxa composition of principal Central European beech forests and their associated environmental drivers by integrating three data sources: (1) 254 historical (1937 – 1948) and resurveyed (2019 – 2022) vegetation relevés of beech-dominated forests sites in the Swiss Jura mountains, (2) derived ecological indicator values for vascular plants regarding temperature, soil moisture, micro-climatic conditions, soil nutrients, pH, humus layer, and light availability, and (3) related data on disturbance/management intensity in these forest sites over the past 75 years, categorized as ‘undisturbed’ and ‘disturbed’ sites. We found a significant decrease in alpha diversity (taxa richness per site) on ‘undisturbed’ sites (loss of 7.0 ± 1.48 taxa) but stability on ‘disturbed’ sites (gain of 2.1 ± 5.71 taxa). Both beta (Jaccard dissimilarity) and gamma diversity (overall taxa richness) increased over the study period. The average ecological indicator values per site (EIV‾s) consistently indicated climate warming impacts on all sites ranging from 390 to 1480 m a.s.l., while effects of acidic rain on soil pH and nitrogen deposition on soil fertility were negligible, except in densely populated lowland forest areas. The EIV‾s for light and micro-climatic conditions differed between ‘undisturbed’ and ‘disturbed’ sites, indicating darker and more oceanic, and more open and continental conditions, respectively. The decrease in alpha diversity on ‘undisturbed’ sites corresponded primarily with reduced light availability, suggesting that stand maturation is the main driver of taxa loss while climate warming and pollution mainly affected composition rather than taxa richness. In contrast, the rise in beta and gamma diversity likely stems from changes in forest management and disturbance regimes, which have increased structural diversity with various micro-climatic niches enriching the taxa pool. In conclusion, our study demonstrates the ability to differentiate the profound effects of climate warming and pollution agents on forest composition and underscores the critical role of adaptive management in mitigating these impacts. By fostering structural diversity and biodiversity, adaptive management enhances the resilience of forests, enabling them to better adapt to evolving environmental conditions.

Late-orogenic extension ceases with waning plate convergence: The case of the Simplon normal fault (Swiss Alps)

The Simplon normal fault in the Western Alps caused tens of kilometers of orogen-parallel extension during convergence of the European and Adriatic plates, but the slip rate of the fault and the time when normal faulting ended are still debated. Here, we constrain the slip history of the Simplon fault with low-T thermochronology and thermo-kinematic modeling. Closely spaced samples from an elevation profile in the center of the fault yield zircon (U–Th)/He ages (ZHe) that are nearly invariant over an altitude of 1.4 km and cluster around ∼6 Ma. In contrast, apatite (U–Th)/He ages (AHe) increase with altitude from 3.4 ± 0.3 to 4.6 ± 0.7 Ma, while the AFT ages range from 4.4 ± 0.7 to 5.8 ± 1.5 Ma. In addition, recently published 40Ar/39Ar ages constrain that our samples moved through the brittle-ductile transition (i.e., ∼300 °C) at 8–10 Ma. Our thermo-kinematic inverse modeling shows that these age data can be explained by a single phase of normal faulting, which lasted from 19.8 ± 1.8 to 5.3 ± 0.3 Ma and caused 45 ± 10 km of extension. The slip rate of the 30°-dipping model fault is 3.5 ± 0.3 km/Myr and equivalent to an exhumation rate of ∼1.8 km/Myr. Our modeling reveals that the altitude-dependent difference between ZHe and AHe ages reflects the thermal relaxation after faulting stopped at ∼5.3 Ma. Since then, exhumation by erosion continued at a rate of ∼0.5 km/Myr. Remarkably, the end of slip on the Simplon fault coincides with the cessation of reverse faulting at 6 ± 2 Ma in the external crystalline massifs of the Alps (Aar, Mont Blanc, Aiguilles Rouges) and with a decrease in strain rate by one order of magnitude at 5-4 Ma in the Swiss molasse basin and the Jura mountains. This temporal coincidence suggests that normal faulting in the internal part of the Alps ceased when plate convergence waned and the under-thrusting of European continental lithosphere beneath the Adriatic plate came to an end.

OpenStreetMap for multi-faceted climate risk assessments

Natural hazards pose significant risks to human lives, infrastructure, and ecosystems. Understanding risks along all these dimensions is critical for effective adaptation planning and risk management. However, climate risk assessments mostly focus on population, economic asset values, and road or building infrastructure, because publicly available data on more diverse exposures are scarce. The increasing availability of crowd-sourced geospatial data, notably from OpenStreetMap, opens up a novel means for assessing climate risk to a large range of physical assets. To this end, we present a stand-alone, lightweight, and highly flexible Python-based OpenStreetMap data extraction tool: OSM-flex. To demonstrate the potential and limitations of OpenStreetMap data for risk assessments, we couple OSM-flex to the open-source natural hazard risk assessment platform CLIMADA and compute winter storm risk and event impacts from winter storm Lothar across Switzerland to forests, UNESCO heritage sites, railways, healthcare facilities, and airports. Contrasting spatial patterns of risks on such less conventional exposure layers with more traditional risk metrics (asset damages and affected population) reveals that risk hot-spots are inhomogeneously and distinctly distributed. For instance, impacts on forestry are mostly expected in Western Switzerland in the Jura mountain chain, whereas economic asset damages are concentrated in the urbanized regions around Basel and Zurich and certain train lines may be most often affected in Central Switzerland and alpine valleys. This study aims to highlight the importance of conducting multi-faceted and high-resolution climate risk assessments and provides researchers, practitioners, and decision-makers with potential open-source software tools and data suggestions for doing so.

3D‐seismic evidence for thick‐skinned tectonics in a ‘classic’ thin skinned tectonics region (external Alpine foreland, Switzerland)

AbstractThe north‐western Alpine foreland in Switzerland and France comprises the Late Miocene Jura Mountains, considered a type example for thin‐skinned thrusting where deformation of the sedimentary cover is decoupled from the basement along a regional basal detachment. To what extent basement faults were involved during its deformation is a matter of debate. We use 3D seismic data to investigate the deformation style along the easternmost tip of the Jura range in unprecedented detail. Here, basement‐rooted normal faults were not only repeatedly reactivated before thrust belt formation but also contemporaneously active as reverse/transpressional faults. They either propagated up into the Mesozoic succession without interruption (‘hard linkage’) or apparently controlled the localisation of Mesozoic faults via smaller‐scale shear zones (‘soft linkage’). Our analysis of the resulting fault geometries questions the existence of a large‐scale basal detachment in this area and points out the importance of thick‐skinned fault reactivation.

“The pesticides burned the grass and the know-how”: Farmers’ oral history and chemoethnography of Swiss Jura slowly violent waterscapes

Farmers and beekeepers of the Swiss Jura mountains have been exposed to toxicity and socioeconomic vulnerability. Based on a combination of oral history and chemo-ethnographic interviews, research participants explore how water, chemicals, and social activities are interacting and intra-acting to melt into what we call ‘hydrochemosocial hybrids’. They narrated their histories of practices affecting the quality of water and ecosystems. Their testimonies indicate that controversial projects of agriculture intensification inflict slow violence by exposure to toxic chemicals. Participants respond to this violence in quiet forms of solidarity, care, and resistance. Our analysis at the junction of chemoethnography and research on hydrosocial territory combines theoretical lenses into an opening field of ‘hydrochemosocial research’.

Comparative genetic and demographic responses to climate change in three peatland butterflies in the Jura massif

Climate is a main driver of species distributions, but all species are not equally affected by climate change, and their differential responses to similar climatic constraints might dramatically affect the local species composition. In the context of climate warming, a better knowledge of the ability of dispersal-limited and habitat-specialist species to track climate change at local scale is urgently needed. Comparing the population genetic and demographic impacts of past climate cycles in multiple co-distributed species with similar ecological requirements help predicting the community-scale response to climate warming, but such comparative studies remain rare. Here, we studied the relationship between demographic history and past changes in spatial distribution of three protected peatland butterfly species (Boloria aquilonaris, Coenonympha tullia, Lycaena helle) in the Jura massif (France), using a genomic approach (ddRAD sequencing) and species distribution modeling (SDM). We found a similar and narrow thermal niche among species, and shared demographic histories of post-glacial decline and recent fragmentation of populations. Each species functions as a single metapopulation at the regional scale, with a North-South gradient of decreasing genetic diversity that fits the local dynamics of the ice cover over time. However, we found no correlation between changes in the quantity or the quality of suitable areas and changes in effective population size over time. This suggests that species ranges moved beyond the Jura massif during the less favorable climatic periods, and/or that habitat loss and deterioration are major drivers of the current dramatic decline observed in the three species. Our findings allow better understanding how history events and contemporary dynamics shape local biodiversity, providing valuable knowledge to identify appropriate conservation strategies.

The type of forest edge shapes snail assemblages at forest–pasture transitions

Semi-natural, nutrient-poor calcareous grasslands are local biodiversity hotspots that are increasingly threatened by land use intensification, abandonment, or indirect effects from adjacent habitats. The habitat quality of these grasslands is often influenced by neighbouring forests or intensively managed agricultural land. For example, shrubs encroaching on grassland reduce the sensitive habitat, but at the same time represent a new habitat type (transition zone at gradual forest edge). We investigated the effects of gradual and abrupt forest edges on the species richness, abundance, species composition, functional diversity and number of species of conservation importance (red-listed species) of land snail assemblages at forest–pasture transitions in the Jura Mountains, Switzerland. Forest edge type influenced the snail assemblages in different ways. Transition zones at abrupt forest edges had a higher species richness and more snail individuals than transition zones at gradual forest edges. Transition zones also differed in land snail species composition. At gradual forest edges, the transition zones contained some openland snail species, while those at abrupt forest edges had a similar species composition to the forest interior. Functional diversity was significantly higher for snails in the forests and transition zones at both abrupt and gradual edges than in pastures. In contrast, pastures and transition zones at both abrupt and gradual edges had a significantly higher number of red-listed snail species. Based on our findings, we recommend the creation of gradual forest edges through regular forest management practices, rather than through shrub encroachment into pasture, which could reduce the size of the threatened habitat.

Distinct secondary ice production processes observed in radar Doppler spectra: insights from a case study

Abstract. Secondary ice production (SIP) has an essential role in cloud and precipitation microphysics. In recent years, substantial insights were gained into SIP by combining experimental, modeling, and observational approaches. Remote sensing instruments, among them meteorological radars, offer the possibility of studying clouds and precipitation in extended areas over long time periods and are highly valuable to understand the spatiotemporal structure of microphysical processes. Multi-modal Doppler spectra measured by vertically pointing radars reveal the coexistence, within a radar resolution volume, of hydrometeor populations with distinct properties; as such, they can provide decisive insight into precipitation microphysics. This paper leverages polarimetric radar Doppler spectra as a tool to study the microphysical processes that took place during a snowfall event on 27 January 2021 in the Swiss Jura Mountains during the ICE GENESIS campaign. A multi-layered cloud system was present, with ice particles sedimenting through a supercooled liquid water (SLW) layer in a seeder–feeder configuration. Building on a Doppler peak detection algorithm, we implement a peak labeling procedure to identify the particle type(s) that may be present within a radar resolution volume. With this approach, we can visualize spatiotemporal features in the radar time series that point to the occurrence of distinct mechanisms during different stages of the event. By focusing on three 30 min phases of the case study and by using the detailed information contained in the Doppler spectra, together with dual-frequency radar measurements, aircraft in situ images, and simulated profiles of atmospheric variables, we narrow down the possible processes that could be responsible for the observed signatures. Depending on the availability of SLW and the droplet sizes, on the temperature range, and on the interaction between the liquid and ice particles, various SIP processes are identified as plausible, with distinct fingerprints in the radar Doppler spectra. A simple modeling approach suggests that the ice crystal number concentrations likely exceed typical concentrations of ice-nucleating particles by 1 to 4 orders of magnitude. While a robust proof of occurrence of a given SIP mechanism cannot be easily established, the multi-sensor data provide various independent elements each supporting the proposed interpretations.

Non-Destructive Testing of Dalle de Verre Windows by Fernand Léger and Alexandre Cingria in Switzerland

Dalle de verre windows consist of thick slabs of coloured glass set in a matrix of reinforced concrete. The invention of this special art form is closely linked to the developments in modern architecture in the first half of the 20th century that are characterized by using new technologies such as steel-frame construction, reinforced concrete and the increasing use of glass. Many of these windows are showing damage, some of it severe. Until now, the causes of damage have hardly been investigated and there is still no practical and suitable approach to the analysis of the state of conservation of dalle de verre glazings. One of the main objectives of an interdisciplinary project (2019–2021) was therefore to evaluate the potential of non-destructive techniques for the characterisation of and identification of damage of dalle the verre windows in their structural, physical and climatic context. Various non-destructive methods (Ground-Penetrating Radar, Electric resistivity, Half-cell potential, Ultrasonics, Induction, Magnet and Thermography) have been tested on two prominent dalle de verre examples: the windows created by Fernand Léger for the church of Saint-Germain d’Auxerre in Courfaivre (Swiss Jura mountains) and the large tripartite by Alexandre Cingria once decorating the choir window church of the Franciscan monastery at Fribourg, Switzerland. The results of the analyses presented in this paper provide valuable information on the advantages and limitations as well as the costs of the methods used.

Heat Treatment of Chert in the Early Mesolithic at Rottenburg-Siebenlinden (Southwest Germany)

ABSTRACT Unambiguous evidence for heat treatment in the Early Mesolithic of Southwestern Germany is thus far restricted to one type of raw material and to cave sites of the Swabian Jura region. At the open-air site Rottenburg-Siebenlinden, heat treatment of an additional raw material was proposed. In this paper, we reexamine the lithic assemblage of horizon III, using the best available criterion for recognizing heat treatment: gloss contrast. Through technological analysis of these diagnostic artefacts, we investigate the timing of heat treatment within the reduction sequence. Visual identifications were substantiated by analyzing surface roughness of gloss contrast artefacts. Our results show that heat treatment was regularly applied to a wider range of raw materials than previously thought, during blank production. These findings highlight that the last Central European hunter-gatherers were flexible in terms of material choices and that heat treatment was a more widespread phenomenon than previously thought.

Ensilibility and protein degradation characteristics of forage from mountain grasslands containing tanniferous species

AbstractEnsiling forage from species‐rich mountain grasslands is challenging. Low concentrations of fermentable carbohydrates and the coarse morphological structure of the forage promote the activity of butyric acid forming bacteria. This is associated with the formation of ammonia from protein degradation, resulting in an insufficient pH decline. On the other hand, forage from species‐rich swards may contain tanniferous plant species which contain varying contents of condensed tannins (CT). Therefore, the silage quality of forage prepared from species‐rich mountain grasslands and the role CT may play in silage fermentation was studied. A set‐up of two long‐term mineral fertilization field experiments, located in the Jura mountains and the Alps in Switzerland were used to obtain forage with contrasting species and chemical composition. Collection was done during both the generative and vegetative growth stage from three differently fertilized swards: unfertilised (“0”), fertilized with phosphorus and potassium (“PK”) or fertilized with PK and nitrogen (“NPK”). The forage was wilted to approximately 37% dry matter (DM), chopped to 2 cm lengths and ensiled for at least 65 days as laboratory‐scale silages. The wilted forage was characterized by concentrations of crude protein between 117 and 130 g/kg DM and water‐soluble carbohydrates varying from 84 to 148 g/kg DM. Concentrations of CT ranged from 6 g to 14 g/kg DM and those of soluble CT from 1.8 to 7.6 g/kg DM. All silages contained butyric acid, irrespective of the type of fertilization or harvest stage (range: 1.5 g to 16 g/kg DM). Concentrations of acetic and lactic acid ranged from 2.1 g to 15.0 g/kg DM and from 21.0 to 44.0 g/kg DM, respectively. Concentrations of unfermented sugar remained high and pH levels were above those expected. Formation of non‐protein‐N (NPN) increased in the range of 130 to 264 g/kg N from wilted to ensiled forage. The negative correlations of CT or soluble CT contents with ammonia‐N or NPN in silage were found in both forage from the generative and vegetative harvests indicating a possible relationship with protein degradation during ensiling.