Project leader: Heinz Veit, Armin Rist
Co-workers: Hans Kallen, Lukas Munz, Sebastian Gygax, Alexander Groos
Financed by: GIUB internally
Duration: 2011 – 2020 (thereafter possible takeover by other institution)
Solifluction is defined as slow superficial downslope movement of substrate induced by ground frost. The occurrence of this phenomenon is often seen as indicator for periglacial activity and the related climate. Therefore, various single effects of environmental factors on the solifluction rate were intensively studied by means of their temporal variability. However, most of these studies were performed in (sub-)polar periglacial regions over short periods neglecting the spatial variability. Addressing these inherent gaps of knowledge, the objective of our study is to develop a quantitative model based on measured data to determine the rate of alpine solifluction depending on environmental factors varying in time and space.
This study is performed at the north slope of Blauberg at Furkapass (Central Swiss Alps) between 2380 m and 2700 m a.s.l. This study site belongs to the Alpine periglacial belt comprising seasonal ground frost on the lower slope and permafrost on the upper slope. The exposition ranges from NNW to NE. Regarding geology, the study site is partly situated in the northern paragneiss zone, partly in the Urseren zone consisting of Mesozoic sediments. Climatically, the study site is at the border of the climate regions Valais and Northern Side of Central Alps resulting in a mean annual air temperature between – 4 °C and -1 °C, an annual precipitation of 2800 to 3200 mm and a mean winter snow depth of 150 cm to 250 cm. Alpine meadows extend up to about 2500 m a.s.l., the open scree slope above up to about 2650 m a.s.l. where fissured rock faces follow.
To reach the objective defined above we measure outcome parameters as well as environmental influencing factors varying spatially and temporally. The outcome parameters are:
Surface displacement on, besides and below 24 lobes at 9 to 12 points for each lobe
Depth-dependent displacement on/below lobes at 2400 m, 2500 m and 2600 m
Digital Elevation Model (DEM) in several years and related terrain increases and decreases
Spatial occurrence and dimensions of solifluction lobes and related landforms
As environmental influencing factors the following are measured:
Air temperature, humidity and pressure, wind speed, precipitation, snow depth and radiation at a meteorological station
Potential solar radiation at 17 points along a transect from 2380 m - 2700 m
Snow depth and water equivalent at 27 points from 2390 m – 2640 m distributed over slope
Bottom temperature of winter snow cover (BTS) at 8 points along transect from 2400 m - 2640 m
Evolution of spatial snow cover distribution by automatic camera
Liquid and plastic limit of soil matrix on/below 9 lobes between 2350 m and 2600 m
Spatial distributed Normalised Difference Vegetation Index (NDVI) by drone in summer
Spatially distributed ground surface temperature depending on daytime in summer and autumn
Depth-dependent ground temperature/water content at 2400 m, 2500 m, 2600 m on/below lobe
Depth of vadose zone at 2400 m, 2500 m, 2600 m on/below lobe
Ground electrical resistivity to detect permafrost by geoelectric soundings from 2500 m - 2600 m
The solifluction movement rates and the related periglacial landforms are controlled by the ground’s hydrological, thermal regime and mechanical behaviour. These primary environmental factors are influenced by secondary ones, i.e. weather/climate, snow, vegetation, geology, substrate and relief which are quantified by tertiary measurable single factors. While the single factors constituting weather/climate, snow and vegetation vary both in time and space, those ones constituting geology, substrate and relief vary mainly spatially (temporally only in the long-term). Based on this concept of variable dependencies the data will be analysed statistically leading to the strived model quantifying solifluction by means of the environmental conditions allowing to involve solifluction in paleo-geoecological reconstructions more reliably.
Project leader: Frank Mayle (University of Reading, UK)
Co-Pi: Heinz Veit
Co-workers: Umberto Lombardo
Financed by: Arts and Humanities Research Council (UK)
The dynamics of past human-environment relationships is one of the most relevant issues in archaeology today. Pre-Columbian (pre-1492) Amazonia provides a case study of a long-standing debate into human-environment interactions. At one end of the spectrum are those who view Amazonia as a largely pristine wilderness which has shaped human history, while at the other are those who argue that Amazonia has been utterly transformed into a domesticated landscape by millennia of human land use. Recent ground-breaking discoveries of vast, pre-Columbian landscape engineering projects - monumental habitation mounds, ring ditches, causeways and canals -- overturn the paradigm that environmental constraints limited cultural development in Amazonia to simple semi-nomadic, hunter-gatherer lifestyles, as practiced by indigenous peoples today. However, the processes by which these complex (stratified) societies emerged and declined, and their relationships with the environment, remain unresolved. This uncertainty stems from a paucity of archaeological data and a lack of the inter-disciplinary collaboration essential for investigation of human-environment interactions. This project therefore assembles an international, multi-disciplinary research team to integrate archaeological and environmental approaches and data to address our overarching research aim:
To determine the relationships between the emergence and demise of stratified societies, food procurement strategies, and environmental conditions in Pre-Columbian Amazonia.
The Paleo-Geoecology Group participates in this project together with the department of Geography and Environmental Sciences at the University of Reading, the department of Archaeology at the University of Reading, the department of American Studies at the University of Bonn, the School of Archaeology at University of Oxford, the Department of Sedimentary and Environmental Geology, Institute of Geosciences, Univ. of São Paulo, Museum of Archaeology and Ethnology, University of São Paulo, Dept. of Sedimentary and Environmental Geology, University of São Paulo.
The main task of the Paleo-Geoecology Group within this project is to reconstruct the evolutionary history of the Bolivian Amazon’s physical landscape and river network in order to determine how changes in flood regime influenced pre-Columbian occupation history and land use.
Project leader: Heinz Veit, Alexander R. Groos
Collaborators: Naki Akçar, Christoph Mayer
Funding: Swiss National Science Foundation (Project no. 187905)
It has long been thought that extreme habitats on earth, including rainforests, deserts, the Arctic and high mountains, have been colonised at a late stage. In recent years, however, there is growing evidence that this is not necessarily true. The human species is very adaptable, and wherever humans had sufficient resources for food and water as well as raw materials for the production of tools and weapons, they probably also penetrated inhospitable areas very early on. Our interdisciplinary research group tackles the question when humans started to colonise the Bale Mountains in the southern Ethiopian Highlands.
In sub-project P6, we are investigating the climatic and environmental conditions that prevailed in the Bale Mountains during the last Ice Age, about 50,000-15,000 years ago. Phase 1 of the project provided evidence of early settlement. At that time, the plateau was covered by about 260 km² of ice. However, the maximum ice cover did not occur during the globally coldest period of the last glaciation ca. 24,000 years ago, but well before that, about 40,000 years ago. The climatic conditions that led to this are unclear. In phase 2 of the project, which is now underway, we want to obtain more detailed information on the palaeoecology, temperature and precipitation changes, and the amount of available meltwater by compining geomorphological mapping, surface exposure dating and numerical modelling.
Offizielle Website: Research Unit 2358 - The Mountain Exile Hypothesis
Project leader: Heinz Veit
Co-workers: Christian Gnägi, Tobias Messmer, Mareike Trauerstein
Financed by: SNF 200021_149124/1
It has been shown over the past few years that the glaciation and environmental history of the Alps is much more complex than previously assumed. While the dating of glacial sediments by luminescence has currently seen important improvement, it is still methodologically challenging. Another approach for constraining the age of glacial deposits is investigating their cover sediments and soils, because soil development (e.g. decalcification depth) and the complexity of cover bed sequences increases with the age of the underlying sediments. Additionally, investigating the cover beds, soils and palaeosols will not only provide indirect information on the time of glacial deposition, but also reflect the later environmental history of the region. Soil chronosequence studies in the alpine foreland have used geomorphological-stratigraphical models in the past, but lacking numerical dating control. Chronological constrains and environmental inter¬pre¬tations drawn from this approach are based on certain theoretical assumptions, such as: a) the glacier advance at about 25 ka ago was the most extensive one of the last glacial cycle, b) the Holocene was a period of land-scape stability, with closed vegetation cover and continuous soil development at least until the arrival of humans, c) periglacial surface features, such as solifluction layers, cryoturbations etc. are of Pleistocene age, because the formation of such features requires intense soil frost which is absent during the Holocene, and d) well-developed Bt-horizons reflect full interglacial environmental conditions (Holocene, Eem or older).
In this project we aim to challenge all these basic assumptions by combining intensive fieldwork with luminescence-¬dating. This is based on preliminary data we have obtained during the recent years, which contradict these “classical” views of the Upper Quaternary. Instead, our hypotheses are: a) the most extensive advance of the Rhone-Aare-glacier occurred prior to 25 ka, b) during the Early Holocene (ca. 10-8 ka) there was widespread erosion and sedimentation, indicating a relatively open landscape, c) frost dynamics with cryoturbation-like structures occurred at the same period (Early Holocene), probably due to pronounced seasonal contrasts (very cold winters, warm summers), and d) Bt-formation was possible during warmer periods of the Birrfeld glaciation and are not restricted to interglacials in a classical sense.
To prove these assumptions, we have to understand the spatial distribution of soils, their detailed structure, geochemical composition, and we need to know the age of the parent materials. Therefore, we aim at carrying out intensive fieldwork (studying gravel pits, hand- and motor corings, excavations), geochemical/mineralogical lab work, as well as luminescence and radiocarbon dating. The study will be realized in the area of the former Rhone-Aare-glacier glacier between Solothurn and Niederbipp, as well as the younger deposits in the lower Aare valley and the lake district (Lake Biel, Lake Neuchatel). This region features moraines and terraces of the supposed 25 ka advance, as well as deposits of older glaciations.