Forschungsprojekte Gruppe für Paläo-Geoökologie
Alpine solifluction and its environmental controls – spatio-temporal monitoring at Blauberg (Furkapass, Central Swiss Alps)
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.
The Mountain Exile Hypothesis: How humans benefited and reshaped African high altitude ecosystems during the Quaternary climatic changes; Teilprojekt P6: Glacial Chronology
Project leader: Heinz Veit, Naki Akçar
Co-workers: Alexander Groos
Financed by: SNF 200021E-165446/1
Reconstructing past glaciations and glacier variations is one of the top proxies in paleoclimatic, paleoecological and climate change research in mountains worldwide. The alternating shrinking and advancing ice bodies clearly indicate changes in mass balance over time, mainly influenced by temperature, precipitation and cloudiness/insolation. Knowing the glacier history in terms of total ice covered area, timing and paleoclimate, is a prerequisite for understanding probable early human distribution patterns and environments in the Bale Mountains. Project P6 has the following three main tasks:
a) Reconstructing the extent of the former ice cover.
b) Establishing a glacial chronology through 14C and 36Cl dating.
c) Mapping and analyzing past periglacial and especially permafrost features.
Offizielle Website: The Mountain Exile Hypothesis
Soils and paleosols on the Swiss Plateau in the area of the former Rhone-Aare-glacier
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.
Human presence, anthropogenic landscape modifications and environmental change during the Holocene in the Llanos de Moxos (LM) - Bolivian Amazon
Period: 2012 - 2015
Project leader: Prof. Heinz Veit
Co-workers:Umberto Lombardo (Post-Doc), Leonor Rodrigues (PhD)
Financed by: SNF 200020-141277/1
Project area: Bolivia (Llanos de Moxos, Beni)
The current project is designed as a continuation of our SNF project 200021 – 1222. The research focuses on human-environment interactions during the Holocene in the southern Amazon Basin.
Within the SNF project 200021 – 1222 we have reconstructed the mid to late Holocene fluvial dynamics of the south-eastern LM and highlighted the links between fluvial dynamics and pre-Columbian settlement patterns there; we have put forward a new interpretative model for pre-Columbian agricultural earthworks; and we have discovered late Pleistocene/early Holocene shell middens, which could represent the oldest archaeological sites in central and south Amazonia. Our results suggest that the periods of human presence in the LM and the levels of social complexity reached by the pre-Columbian inhabitants were closely linked to environmental changes that took place during the Holocene. However, new questions have arisen as a result of our findings that need to be addressed in order to fully understand the history of the LM during the Holocene. These will be the focus of the proposed project:
What did the landscape of the LM look like during the early-Holocene at the time of the first pre-ceramic settlers? What kind of impact did the first settlers have on the environment? Which were the causes of the environmental changes that took place during the mid-Holocene? Which were the productive strategies employed by pre-Columbians in the late Holocene? How did pre-Columbian agriculture change soil properties? In order to address these questions we need to supplement the data we already have with more data from paleoecological archives that we have not yet investigated or we have only just started to investigate. Therefore, the present project includes the analysis of lacustrine sediments, the archaeological excavations of early Holocene shell middens and a detailed analysis of soils and sediments from sites with agricultural earthworks. Pollen and charcoal analysis from lacustrine sediments will help to reconstruct the environment of the LM during the Holocene, detect possible evidence of human fire and/or deforestation during the early and mid-Holocene and will provide the essential data needed to assess the impact pre-Columbian agriculture had on forests and savannahs. Geoarchaeological excavations of the shell middens are likely to lead to the finding of human artefacts, hence the definitive proof that they are anthropogenic; the excavation of soil profiles at several pre-Columbian agricultural sites and at reference sites with “natural” soil will allow us to reconstruct how agricultural fields were managed and to understand the reasons behind the large variety of shapes and locations.
The study of human-environment interactions is fundamental to the correct interpretation of palaeoecological archives. These data are also important in order to assess the possible influence that post-contact re-forestation had on global climate and the resilience of Amazon ecosystems to human disturbance, as well as help inform development and conservation policies for the Amazon Basin today.
Rodrigues, L., Lombardo, U., Fehr, S., Preusser, F. and Veit, H. (2014): Pre-Columbian agriculture in the Bolivian Lowlands: Construction history andmanagement of raised fields in Bermeo, Catena. [Sciencedirect]
Lombardo, U., Denier, S., May, J-H., Rodrigues, L. and Veit, H. (In Press): Human-environment interactions in pre-Columbian Amazonia: the case of the Llanos de Moxos, Bolivia. Quaternary International [Sciencedirect]
Lombardo, U., May, J-H. and Veit, H. (2012): Mid- to late Holocene fluvial activity behind pre-Columbian social complexity in the south-western Amazon basin. Holocene 22: 1035-1045 [Sagepub]
Lombardo, U., May, J-H. and Veit, H. (2012): Geoecological settings as a driving factor behind pre-Columbian human occupation patterns in Bolivian Amazonia. Journal for Ancient Studies 3: 123-129 [eTopoi]
Lombardo, U., Canal-Beeby, E., Veit, H. (2011): Eco-archaeological regions in the Bolivian Amazon: Linking pre-Columbian earthworks and environmental diversity. Geographica Helvetica 66: 173-182. PDF
Plotzki, A., May, J.H. and Veit, H. (2011): Review of past and recent fluvial dynamics in the Beni lowlands, NE Bolivia. Geographica Helvetica 66 (3): 164-172 PDF
Lombardo, U., Canal-Beeby, E., Fehr, S. and Veit, H. (2011): Raised fields in the Bolivian Amazonia: a prehistoric green revolution or a flood risk mitigation strategy? Journal of Archaeological Science 38(3): 502-512 [Sciencedirect]
Lombardo U., (2010): Raised Fields of Northwestern Bolivia: a GIS based analysis. Zeitschrift für Archäologie Außereuropäischer Kulturen 3: 127-149
Lombardo, U., Prümers, H. (2010): Pre-Columbian human occupation patterns in the eastern plains of the Llanos de Moxos, Bolivian Amazonia. Journal of Archaeological Science [Sciencedirect]
- Paleoclimate of the Central Andes (1997-2001)
- Virtueller Campus Schweiz, ALPECOLe (2001-2003)
- Biodiversität und ‚Climate Change’ in den Alpen (2001-2002)
- Paleoclimate of tropical South America: linking Andean highlands (Bolivia) with adjacent lowlands (Bolivia, Brazil) (2003-2004)
- Paläoökologie von Ostbolivien (2005-2006)
- Glacier reconstruction along a N-S Andean Transect (Chile, 30-40°S) using 10Be surface exposure dating (2005-2006)
- 10Be surface exposure dating in the Central Andes (2006-2009)
- FLUVALPS-3000 – Fluvial Variability in the Alps during the last 3000 years (2006-2009)
- Alpenforum 2007, Engelberg (2007)
- Geomorphology and Stratigraphy of postglacial lake beaches in the Northwest Alpine Foreland (2008-2011)
- Holocene hydrogeomorphology and pre-Columbian water management in the Llanos de Moxos, Bolivian Amazon (2009-2012)
- FLUVALPS+ – Fluvial Variability, Climate and Land Use Interactions in Alpine Environments (2009-2012)
- Soils, paleosols and quaternary landscape development of the Swiss Plateau