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ThermoEurope: low temperature exhumation history of the Bergell

English title ThermoEurope: low temperature exhumation history of the Bergell
Applicant Willett Sean D.
Number 138243
Funding scheme Project funding
Research institution Geologisches Institut ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geology
Start/End 01.10.2011 - 31.08.2012
Approved amount 52'977.00
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Keywords (2)

erosion ; alps

Lay Summary (English)

Lead
Lay summary

This project is directed to the determination of the erosion of the Bergell intrusion in the southern Alps of Italy and Switzerland. The Bergell intrusion is 30 Million years old, but it has been brought to the Earth's surface much more recently. We will measure the cooling ages in the mineral apatite by measuring the Uranium, Thorium and Helium. The ratio of these elements gives us the time at which the mineral cooled below 100 degrees. By measuring apatite cooling ages from throughout the Bergell, we can determine the pattern of cooling and thus the pattern of erosion of the surface. We will determine whether this erosion pattern implies control by tectonic processes or climatic processes, for example related to the onset of glacial erosion 1 to 2 million years ago.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
The Exhumation history of the European Alps inferred from linear inversion of thermochronometric data
Fox Matthew, Herman Fr{é}d{é}ric, Willett Sean D, Schmid Stefan M (2016), The Exhumation history of the European Alps inferred from linear inversion of thermochronometric data, in American Journal of Science, 316(6), 505-541.
A linear inversion method to infer exhumation rates in space and time from thermochronometric data
Fox M., Herman F., Willett S.D., may D.A. (2014), A linear inversion method to infer exhumation rates in space and time from thermochronometric data, in Earth Surf. Dynam. Discuss., 1, 207-259.
Rock uplift and erosion rate history of the Bergell intrusion from the inversion of low temperature thermochronometric data
Fox Matthew, Reverman Rebecca, Herman F., Fellin Maria G, Sternai Pietro, Willett Sean D (2014), Rock uplift and erosion rate history of the Bergell intrusion from the inversion of low temperature thermochronometric data, in Geochemistry, Geophysics, Geosystems, 15(4), 1235-1257.
Neogene exhumation history of the Bergell massif (southeast Central Alps)
Mahéo Gweltaz, Gautheron Cécile E., Leloup Philippe Hervé, Fox Matthew R., Tassant-Got Laurent, Douville Éric (2013), Neogene exhumation history of the Bergell massif (southeast Central Alps), in Terra Nova, 25(2), 110-118.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
EGU Talk given at a conference Late Cenozoic Exhumation of the Alps 09.04.2012 Vienna, Austria Willett Sean D.; Fox Matthew;
AGU Talk given at a conference A Quantification of erosion rates in mountain ranges using low termperature thermochronology 05.12.2011 San Francisco, United States of America Fox Matthew;


Associated projects

Number Title Start Funding scheme
120539 Thermo-Europe - Coupled climatic/tectonic forcing of European topography revealed through thermochronometry (IP6) 01.09.2008 Project funding (special)

Abstract

This proposal is a request to continue and complete a project which was originally funded through the TOPOEurope Eurocore program of the ESF. This project was part of the THERMO-Europe CRP comprising about 10 projects. The original CRP had as its aims, the addressing of the following questions:Can we document and quantify variations in erosion rates in, and/or sediment flux from, mountain belts through time and can we link these two measurements? What resolution can we achieve in the establishment of a record of erosion rates through time?Can we establish the timing of these variations with sufficient temporal and spatial resolution to enable correlation between different study areas?Can we use this information to discriminate climatic and tectonic forcings on the topographic evolution of the region?Can we reveal changes in topography due to changing rates and processes of erosion (e.g., increased relief due to valley carving)?Can we document and model the tectonic response to changing erosion rates and topography, and can we establish couplings in the system?We aim to address these questions by combining (a) acquisition of new thermochronologic data on denudation rates and seismic data on sediment-flux from selected key areas; (b) development of new methods to increase the resolution of the thermochronologic record; (c) development of quantitative interpretational techniques that permit us to extract information on relief development and transient exhumation rates and (d) investigation of the potentially coupled effect of climate-induced and tectonic variability in exhumation rates.This proposal is for a continuation of the work started in IP6 “He thermochronometry with focus on the Bergell intrusion”. However, the research was necessarily intertwined with work proposed in IP6 , “Late stage exhumation of the Adamello Massif”, as both projects were being conducted by PhD students and PIs working closely together with common objectives.The main effort in this project over its first phase has been the development of a new thermochronometry analysis method. We have developed a formal inverse procedure to extract exhumation rates from spatially distributed low temperature thermochonometric data. Our method is based on a Gaussian linear inversion approach in which we set up a linear problem relating exhumation rate to thermochronometric age with rates being parameterized as a variable in both space and time.Much of the analysis of our thermochron method has been done with synthetic data or limited, high-quality data from well-studied areas. Results from the full Alps remain preliminary. We need to conduct a more extensive analysis of the full Alpine data set, including sensitivity to prior parameters and spatial correlation, and conduct a resolution assessment.Approximately 40 samples have been collected within the Bergell intrusive for thermochronometry with an emphasis on vertical profiling and extensive spatial coverage across, and along, the large, glaciated valleys. By the end of the first phase of this project most will have been dated by conventional U-Th/He. However, first ages indicate most will not be young enough to determine the magnitude and timing of glacial incision. The remaining samples will be dated with conventional U-Th/He , but we will also select some to be dated by 4He/ 3He method. We propose to do this through this one-year continuation grant.
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