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BERYLLIUM: Boulder Exhumation Rates (over 10^5 Years) in Low-gradient Landscapes In an Upland Mediterranean Area

English title BERYLLIUM: Boulder Exhumation Rates (over 10^5 Years) in Low-gradient Landscapes In an Upland Mediterranean Area
Applicant Egli Markus
Number 162338
Funding scheme Project funding (Div. I-III)
Research institution Geographisches Institut Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Pedology
Start/End 01.04.2016 - 30.09.2019
Approved amount 258'773.00
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All Disciplines (2)

Discipline
Pedology
Geomorphology

Keywords (8)

Isotope tracers; Temporal evolution; Soil erosion; Boulder fields; Weathering; Cosmogenic nuclides; 10Be; 239+240Pu

Lay Summary (German)

Lead
Böden und Landschaften entstehen über Jahrtausende auf komplexe und nicht lineare Weise. Als Folge von wechselnden Umweltbedingungen ändern sich die Bodenabtragsraten substantiell. Dieser Tatsache wurde bislang kaum Rechnung getragen, da es äusserst schwierig ist, Erosionsraten über die Zeit von Jahrtausenden zu rekonstruieren. Wohl definierte Bedingungen und ein geeigneter Ansatz sind nötig.
Lay summary

Inhalt und Ziele des Forschungsprojekts

Durch oberflächlichen Abtrag (Boden, Sediment) kann es vorkommen, dass begrabene Felsblöcke mit der Zeit freigelegt werden können. Diese scheinen wie aus dem Boden zu „wachsen“. Wenn nun die variierende Geschwindigkeit der Freilegung über die Zeit bestimmt werden kann, können wechselnde Erosionsraten abgeleitet werden. Eine optimale Möglichkeit dazu bietet sich im Hochland des Sila-Gebirges von Kalabrien (Italien). Die Felsblöcke haben eine granitische Zusammensetzung und deren Freisetzungsrate kann mit kosmogenen Nukliden bestimmt werden. Unsere Hypothese ist, dass diese Felsblöcke ein Schlüsselelement für die Rekonstruktion von Boden-Erosionsraten über das gesamte Holozän und Teile des Pleistozäns sind. Um einen Vergleich mit aktuellen (letzte Jahrzehnte) Erosionsraten zu erhalten, werden diese mit kurzlebigen, radioaktiven Isotopen in Böden bestimmt (239+240Pu;  aus Atombombentests der 1960-er Jahre).

 

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Die Auflösung der zeitlichen Komponente der Bodengenese ist schwierig. Phasen mit progressiver und regressiver Bodenbildung wechseln sich ab. Über den gewählten Ansatz sollte es möglich sein, einen besseren Einblick in die Dynamik der Bodengenese zu erhalten.
Direct link to Lay Summary Last update: 12.02.2016

Responsible applicant and co-applicants

Employees

Publications

Publication
Climate and relief-induced controls on the temporal variability of denudation rates in a granitic upland
(2019), Climate and relief-induced controls on the temporal variability of denudation rates in a granitic upland, in Earth Surface Processes and Landforms, –.
Denudation variability of the Sila massif upland (Italy) from decades to millennia using 10Be and 239+240Pu
(2018), Denudation variability of the Sila massif upland (Italy) from decades to millennia using 10Be and 239+240Pu, in Land Degradation & Development, 29(10), 1-17.
Palaeoclimate, glacier and treeline reconstruction based on geomorphic evidences in the Mongun-Taiga massif (south-eastern Russian Altai) during the Late Pleistocene and Holocene
(2018), Palaeoclimate, glacier and treeline reconstruction based on geomorphic evidences in the Mongun-Taiga massif (south-eastern Russian Altai) during the Late Pleistocene and Holocene, in Quaternary International, 470, 26-37.
Linking tephrochronology and soil characteristics in the Sila and Nebrodi Mountains, Italy
(2017), Linking tephrochronology and soil characteristics in the Sila and Nebrodi Mountains, Italy, in Catena, 158, 266-285.
Decomposition and stabilisation of Norway spruce needlederived material in Alpine soils using a 13C-labelling approach in the field
(2016), Decomposition and stabilisation of Norway spruce needlederived material in Alpine soils using a 13C-labelling approach in the field, in Biogeochemistry, 131, 321-338.
Tracing landscape evolution of the Sila massif: surface exposure dating of boulders using 10Be
(2016), Tracing landscape evolution of the Sila massif: surface exposure dating of boulders using 10Be, Laboratory of Ion Beam Physics, Zurich.

Collaboration

Group / person Country
Types of collaboration
Prof. Dr. Christine Alewell, Institute of Environmental Geosciences, University of Basel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Dr. Fabio Scarciglia DiBEST - Dipartimento di Biologia, Ecologia e Scienze della Terra Università de Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Dr. Michael Ketterer, Chemistry, Metropolitan State University of Denver United States of America (North America)
- Publication
- Research Infrastructure
Dr. Marcus Christl, Laboratory of Ion Beam Physics, ETH Zurich Switzerland (Europe)
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
EGU General Assembly 2019 Poster Going beyond average rates – Identifying responsible drivers for temporal and spatial denudation variations using in-situ 10Be on a variety of granitic landscape features 07.04.2019 Vienna, Austria Raab Gerald; Egli Markus;
The second international young scientists’ forum on soil and water conservation and ICCE symposium Talk given at a conference Modelling soil erosion dynamics over millennia using granite landforms, in-situ 10Be and 239+240Pu 27.08.2018 Moscow, Russia Egli Markus; Raab Gerald;
Young Geomorphologist meeting Talk given at a conference A story of granite landforms and surface denudation variations 25.05.2018 Stadtoldendorf, Germany Egli Markus; Raab Gerald;
EGU General Assembly 2018 Poster Using granite landforms to decrypt soil erosion variations over millennia with in-situ 10Be and 239+240Pu 08.04.2018 Vienna, Austria Egli Markus; Raab Gerald;
EGU General Assembly 2018 Talk given at a conference Late Pleistocene and Holocene palaeoclimate, glacier and treeline reconstruction based on geomorphic evidences in the Mongun-Taiga massif (south-eastern Russian Altai) 08.04.2018 Vienna, Austria Raab Gerald; Egli Markus;
Goldschmidt 2017 Talk given at a conference Deciphering Landscape Archives of the Sila Massif by linking 10Be & 239/240Pu 13.08.2017 Pris, France Egli Markus; Raab Gerald;
EGU General Assembly 2017 Poster Linking tephrochronology and soil characteristics in the Sila and Nebrodi Mountains, Italy 08.04.2017 Vienna, Austria Raab Gerald; Egli Markus;
EGU General Assembly 2017 Talk given at a conference Tracing Landscape Evolution of the Sila Massif using 10Be 08.04.2017 Vienna, Austria Egli Markus;


Self-organised

Title Date Place
Visualizing Science 07.04.2019 Vienna, Austria

Communication with the public

Communication Title Media Place Year
Media relations: print media, online media Eis am Stiel in der Bodenforschung Web German-speaking Switzerland 2019

Associated projects

Number Title Start Funding scheme
170715 Evolving bedrock erosion from modelled cosmogenic nuclide concentrations through time (EVENT) 01.08.2016 International short research visits
147421 Rock boulders as indicators of soil erosion (RAISE) 01.02.2013 International short research visits
134479 Influence of permafrost on chemical weathering and erosion in high Alpine areas 01.09.2011 Project funding (Div. I-III)

Abstract

Landscape surfaces and soils are known to evolve in complex, non-linear ways over thousands of years. As a result of changing environmental conditions over millennia, soil erosion and denudation processes also change substantially. Currently, our knowledge in this field is incomplete and very fragmented. Usually, only averaged long-term erosion or denudation rates are determined for soils and landscapes. The fact that soil erosion processes are discontinuous over time is an aspect that is in most cases completely neglected. An evolutional approach would be, thus, necessary to address such an issue. Such a task is however difficult to be fulfilled. Well-defined (or -controlled) settings are needed to calculate soil mass balances and particularly mass losses due to erosion for a given soil profile.Landscapes affected by intense erosion and denudation may be characterized by boulder fields or “tor” and “bornhardt” landforms, i.e. tower-like or dome-shaped, often castellated, residual rock boulders (resistant to erosion) “growing” from gentle landforms. Determining the speed of boulder exhumation, soil erosion rates over different time periods can be deduced. Using cosmogenic nuclide techniques (10Be), the vertical profile of boulders surfaces can be dated. This allows the determination of their exhumation rate and subsequently the calculation of soil erosion rates over time-intervals (continuous and over millennia). This would then enable a comparison of past erosion rates to modern rates. Modern rates (covering several decades) of soil erosion can be determined by other isotope techniques (e.g., 239+240Pu in the surrounding soils).Ideal settings and a considerable dataset about chemical and mineral weathering and first rather larger scale estimates of erosion rates are available for the Sila Massif in southern Italy. This Mediterranean environment represents a tectonically active area. The upland plateaus consist of old planation surfaces, bordered by steep slopes, and are characterised by granitic spheroidal boulders which form wide boulder fields. We consequently have the hypothesis that by measuring the in situ produced 10Be content (in quartz) at different height 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 of surrounding weathered materials (grus or saprolite) and soils be obtained. This would be an elegant way to calculate erosion rates for different time-steps that cover almost the entire period of soil evolution (estimated to be in the order of 100 ka or more). Such an approach would give insight into a) the overall denudation and erosion rates over the whole periodb) erosion and denudation rates during time segments of the Pleistocene and Holocenec) volumes of loose material that were removed from the uplands and that entered the drainage river system in this time span. The chosen multi-methodological approach will allow for a mutual control and cross-check of such data. The methods include geomorphic mapping to derive overall soil erosion rates at the Sila uplands, vertical sampling of boulders and determination of the speed of their long-term exhumation (out of weathering profiles and soils) to derive soil erosion rates and the determination of soil erosion rates over given time intervals using different isotopes (in soils; 10Be for long-term rates and Pu for short-term rates). The exhumation rate of rock boulders will be determined by using in situ cosmogenic nuclides (10Be). An independent comparison will be made possible by estimating the long-term (millennial time scale), average erosion rates using in situ-produced 10Be in soils. In addition, existing geomorphic data (geomorphic mapping of palaeosurfaces) of the region will be evaluated to derive estimates of average surface erosion rates. This allows a comparison and cross check of the data derived from 10Be measurements. Short-term erosion rates will be estimated using 239+240Pu isotopes in soils. Furthermore, d13C in soils will be tested as a qualitative soil erosion indicator. This multi-methodological approach allows for a cross-check and validation of the obtained results and enables the derivation of temporal erosion rates from decades over millennia. Such an approach that uses soils, boulders and geomorphic mapping to determine soil erosion and that tries to derive soil erosion rates over continuous time-intervals is certainly novel has not yet been performed so far.
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