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Department of Geography Geochronology

Ongoing research projects

SoilCreep
The mystery of biogenic soil creep: the biogeomorphic role of trees in temperate and tropical forests and its ecological consequences
Funding: Czech Science Foundation (2019-2022)
GIUZ PI: Markus Egli
Project PI: Pavel Samonil (VUKOZ, Czech Republic)
Keywords: Tree uprooting, Denudation, soil creep, 10Be, 239+240Pu, Tree census
Participating institutions: VUKOZ, GIUZ, University of Kentucky, U.S.A., Global Forest Research Network

 

Soil creep seems to be influenced substantially by trees. The aim of project is therefore to find out how long-term and short-term soil erosion and redistribution rates relate to the biogeomorphic impact of trees. Radial growth of tree roots and particularly tree uprooting are hypothesised to distinctly affect hillslope processes and thus soil mass movements. Erosion and redistribution rates of soils will be detected by using 10Be and Pu-isotopes. We will quantify the current volume of soil that is mechanically influenced by trees. This data will be statistically modelled over time on existing up to 40-yr long observations of forest dynamics (1000000 trees in database). Effects of trees on soils will be compared using repeated laser scanning covering a 10-yr period (recent changes), radiometric analyses of soils and dendrochronology to establish regional conceptual models of soil mass movement as a function of climate.

BERYLLIUM
Boulder Exhumation Rates (over 105 Years) in Low-gradient Landscapes In an Upland Mediterranean Area
Funding: snf (2016-2020)
GIUZ PI: Markus Egli
Co-PIs: Fabio Scarciglia, Kevin Norton, Mike Ketterer
Keywords: Erosion, 10Be, weathering
Participating institutions: GIUZ, University of Calabria, Victoria University of Wellington (NZ), Laboratory of Ion Beam Physics ETHZ, Metropolitan State University of Denver
PhD student GIUZ: Gerald Raab

Landscape and soil changes are strongly coupled to chemical and physical (erosion) weathering and soil production. The erosion rate is preserved in the signal of cosmogenic nuclides (e.g., 10Be) in stream sediments or even directly in a soil profile. Well-defined (or -controlled) settings are needed to calculate mass balances for a (tectonically active) catchment. Ideal settings are given for the Sila massif in southern Italy (and consequently in a Mediterranean environment). The upland plateaus consist of old planation surfaces, bordered by steep slopes, and are characterised by granitic spheroidal boulders which form wide boulder fields. These boulders seem to 'grow' out of the surface with time. Consequently, by measuring the 10Be content at different levels along a rock boulder (from the soil surface to the top of boulders), the age(s) of exposure can be derived and subsequent total denudation rates will be obtained. This seems an elegant way to calculate erosion rates for different time-steps that cover almost the entire period of soil evolution. A comparable situation is encountered on the southern island of New Zealand where tors are exhumated due to erosion.

 

CORRELATE
Concurrent evolution of erosion rates, weathering and profile development of high alpine and agricultural soils: a 4-D approach
Funding: cooperation UZH – ZALF – Wageningen University (2017-2020)
Project PIs: Markus Egli, Michael Sommer
Keywords: Co-evolution, Erosion, 10Be, 239+240Pu, weathering
Geographic focus: Uckermark (Germany)
Participating institutions: ZALF (Germany), GIUZ, Kansas State University (US), Wageningen University (NL), Laboratory of Ion Beam Physics ETHZ, Metropolitan State University of Denver
PhD student GIUZ: Francesca Calitri


Global change is expected to affect landscapes and mass fluxes from and into soils. Three sets of processes shape these changes: weathering, soil profile development and lateral redistribution of material (erosion and deposition). It is well-known that these interact strongly (i.e., co-evolve) through their effects on the soil. This co-evolution and changing drivers, such as climate and land use, lead to complex soil development in time and space. Periods with dominantly progressive processes (e.g., soil deepening, weathering) alternate with periods with dominantly regressive processes (e.g., erosion) due to fast and substantial changes in drivers. As a result, short-term soil redistribution (years to decades) can differ substantially from long-term soil redistribution (centuries to millennia).
This research focuses on short- and long-term surface mass redistribution rates. Two formerly glaciated case study sites have been selected: an Alpine area close to the permafrost border (Upper Engadine, Switzerland) and a hummocky ground moraine region that is intensively used for agriculture (Uckermark, Germany).
Long-term erosion rates will be quantified using cosmogenic 10Be. Short-term erosion rates will be estimated using 240Pu/239Pu isotope ratios. Additionally ∂13C is applied as a qualitative soil erosion indicator. A novel soil-landscape evolution model (LORICA) will then be used to be calibrated and validated with measured rates and the available geo-datasets and to simulate the past and future co-evolution of soil and surface processes in the study areas.

 

HILLSCAPE (HILLSlope Chronosequence And Process Evolution)
Identifying dominant controls on hillslope functioning and feedback processes by interdisciplinary experiments along a chronosequence
Funding: DACH (2017-2021)
Project PIs: Markus Weiler, Michael Scherer-Lorenzen, Theresa Blume, Ilja van Meerveld, Markus Egli
Participating institutions: University Freiburg, GFZ Potsdam, University of Zurich, Metropolitan State University of Denver (Mike Ketterer)
PhD student GIUZ: Alessandra Musso

Some soil properties are persistent but others can change rapidly, with significant effects on biogeochemical cycles, water quantity and quality. This is particularly true at the hillslope scale, where lateral and vertical transport processes interact over different timescales. Water and vegetation shape surface and subsurface properties through weathering, soil development, and erosion. These processes, in turn, determine water movement through and over hillslopes and alter vegetation distribution. Although all of these processes affect each other, their numerous interactions have only recently become a research focus. HILLSCAPE will use a chronosequence of highly instrumented hillslopes in high alpine areas (Sustenpass and Klausenpass) to measure, analyse and model hillslopes function and development over a range of time scales. It will follow an “all measurements on all plots” approach to ensure integration of the different datasets and insights. Better knowledge of hillslope processes and hillslope development is crucial for implementing effective restoration schemes for degraded or artificial hillslopes.

 

DecAlp: Effect of climate on coarse woody debris decay dynamics and incorporation into the soils of forested Alpine areas (DACH project)
Funding: DACH (2012-2018)
Project PIs: Markus Egli, Jean-Michel Gobat, Heribert Insam, Gabriele Broll, Paolo Cherubini
Keywords: landscape evolution, humus forms, organic matter degradation, spatio-temporal modelling
Geographic focus: Alpine sites in Trentino (Italy)
Participating institutions: Laboratory Soil & Vegetation, University of Neuchâtel, Switzerland; Institute of Microbiology, University of Innsbruck, Austria; University of Osnabrück, Germany; University of Firenze, Italy; Department of Geography University of Zürich
PhD student GIUZ: Marta Petrillo

To understand the different time-scales of organic matter degradation in alpine soils, the leitmotif of the research activities is grouped among 3 different “compartments”: Coarse woody debris CWD (Picea abies, climate) → Humus forms → SOM (soil organic matter). We have the following research questions:
o What time scales are involved in (CWD: Picea abies) decay as a function of climate? How quickly is CWD (Picea abies) integrated into soil organic matter fractions? In which way are the decay products of CWD stabilised?
o How does climate affect coarse woody decay above and especially in the soil of alpine sites?
o What are the links between decay mechanisms and the spatial distribution of humus forms?
o Can the humus form serve as a proxy for the soil biota (mesofauna and micro-biology) for the spatial extrapolation?
Sites in Trentino (Val di Rabbi, Val di Sole) along altitudinal sequences, reflecting climate zones, are investigated, using both an empirical and an experimental approach. The assessment of decay mechanisms along the climosequence sites is performed using dendroecology and –chronology, stable isotope (∂13C, ∂15N), chemical (lignin components ratios) measurements, macro and microbiological investigations and remote sensing techniques.

 

RAISIN
Rates of soil forming processes obtained from soils and paleosols in well-defined settings
Funding: INQUA Project 1216 (since 2012)
PI: Daniela Sauer (Georg-August-University Göttingen)
Co-PIs: Markus Egli, Edoardo Costantini, Dennis Dahms and many others
Keywords: Weathering, chronosequences, soil formation
Geographic focus: worldwide
Participating institutions: University of Göttingen, Germany; Research Centre for Agrobiology and Pedology, Florence, Italy; University of Northern Iowa, Cedar Falls, Iowa, USA, etc.

The project RAISIN represents a core project of the Focus Area Group PASTSOILS. One of the major goals of the Focus Area Group will be achieved through RAISIN: Rates of soil forming processes in different climates, obtained from soils and paleosols in settings where climatic conditions and duration of soil development are known, will be assessed and documented. Thus, the project will provide a solid base for future interpretation of paleosols in the frame of palaeo-environmental reconstructions.
Numerous data on soil development with time, many of them based on soil chronosequence studies in various regions, have been published in the past decades. The main aim of the project is hence to bring together scientists working on rates of soil-forming processes in different regions of the world to share and discuss their results, review and compare published data and finally produce a document representing the current state of knowledge on soil formation rates in different climates. The outcome of the project will be published in a special issue of Quaternary International to make it available to the scientific public. Thus, a common standard for interpreting paleosols in soil-sediment successions in terms of duration and environmental conditions of soil development will be created. Moreover, gaps in our current knowledge will be identified in the process of reviewing existing data in the frame of the project. This will stimulate future research and possibly lead to collaborative projects aiming on closing the identified gaps step by step.

 

Glacier Range
Glacier dynamics in the Wind River Range during the late Pleistocene and Holocene
Funding: Stiftung für wissenschaftliche Forschung an der Universität Zürich, Swiss Government Excellence Scholarship (2016 – 2018)
PI: Raquel Portes
Co-PI: Markus Egli, Dennis Dahms
Keywords: surface exposure dating, radiocarbon dating, glacier dynamics, erosion
Geographic focus: Wind River Range (Wyoming, USA)
Participating institutions: Department of Geography University of Zürich, Department of Geography University of Northern Iowa

Glaciers sculpture landscapes and are significant agents of physical and chemical erosion. The U.S. Rocky Mountain system includes numerous ranges with records of multiple Pleistocene glacial episodes. The Late Pleistocene sequences, and thus glacier dynamics and related effects on landscape, are however largely unknown in the Wind River Range. Moraine deposits are a unique archive for dating glacier fluctuations and, thus, landscape history. Such geomorphic features are a suitable database for predicting or modelling the potential effects of future climate change on landscape dynamics of these regions. We date moraine boulders in the Wind River Range to reconstruct glacier history during the Late Pleistocene/Holocene using 10Be and try to find out how moraine slopes stabilised over time by determining their erosion rates (using, among others 239+240Pu isotopes).

 

Geochronology Summer School

Dating techniques in Environmental Research
Funding: scnat, University of Zürich, WSL, ETHZ (since 2009)
PI: Markus Egli
Co-PIs: Dagmar Brandová, Holger Gärtner (WSL), Paolo Cherubini (WSL), Susan Ivy-Ochs (ETHZ/GIUZ), Dennis Dahms (University of Northern Iowa, Cedar Falls, Iowa)
Keywords: Dating, landscape history, dendrochronology, surface exposure dating, relative dating techniques
Geographic focus: dating techniques, dating applications, radiocarbon, dendrochronology, surface exposure dating, archaeomagnetics, OSL, 210Pb, 137Cs, etc.

 

 

Ongoing master theses

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