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Early Triassic palaeotopography in Central Switzerland

English title Early Triassic palaeotopography in Central Switzerland
Applicant Ramseyer Karl
Number 129792
Funding scheme Project funding (Div. I-III)
Research institution Institut für Geologie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Geology
Start/End 01.03.2011 - 28.02.2014
Approved amount 192'263.00
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Keywords (6)

Triassic transgression; process sedimentology; palynology; Central Switzerland; Aar massif; high-resolution stratigraphy

Lay Summary (English)

Lead
Lay summary
The reconstruction of the first marine transgression after the Hercynian orogeny in the Alpine region has fascinated geologists since the 18th century. Numerous efforts have been made to refine the stratigraphic allocation, depositional environment and paleogeographic position, but the lack of chronostratigraphic ages did not allow the reconstruction of the palaeorelief, the dynamics and the direction of the first marine transgression in Triassic times in Central Switzerland. Similarly, it is still unclear whether the basal Triassic in this part of the Alps is part of the Germanic Basin or belongs to the Tethys realm. The aim of this follow-up project is to reconstruct the depositional environments of the Triassic over a north-south distance of 100 km and an orogen-parallel distance of 75 km in a detailed chronological framework. This restoration will yield information for calculations of transgression rates, palaeorelief and palaeotopography at Early to Middle Triassic times, and for assignments of predominant controls during the transgression. The methods include a detailed analysis of the facies, depositional surfaces, sedimentary structures, micro- and biofacies and stable isotopes. In addition, palynologic analyses will be carried out to determine the ages of deposition. Based on this framework cyclo- and sequence-stratigraphic analyses will be carried out, which will improve the chronological resolution of the Triassic sequences down to a 100 kyr resolution in some locations. Thus, it will become possible to attribute an exact duration for each order of depositional sequence, the transgression rate and the palaeorelief.The importance of the project lies in a high-resolution reconstruction of the dynamics controlling the Triassic transgression, which in turn will result in the estimation of the palaeotopography. If successful, our methodology can be applied to other cases where palaeosurfaces exist but where no information is available about paleorelief. These new insights will improve substantially the paleogeographic picture during Early to Middle Triassic in a transsect from the Jura Mountains to the Central Alps.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Collaboration

Group / person Country
Types of collaboration
Prof. em. Dr. P. Hochuli, Paläontologisches Institut, Universität Zürich, Zürich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
11th Swiss Geoscience Conference Poster The Anisianmarine Transgression in Central Switzerland. Comparison with the Jura Mountains and the Brescian Prealps 15.11.2013 Bern, Switzerland, Switzerland Ramseyer Karl; Rebetez Daniel;
SwissSed 2013 Poster The Middle Triassic (Anisian) marine Transgression in the Tödi area, Central Switzerland 23.02.2013 Fribourg, Switzerland Rebetez Daniel; Ramseyer Karl;
10th Swiss Geoscience Meeting Talk given at a conference Middle Tiassic of the Weiach borehole - results frompalynology and isotope chemostratigraphy 16.11.2012 Bern, Switzerland Rebetez Daniel; Ramseyer Karl;
10th Swiss Geoscience Meeting Poster The middle Triassic marine Transgression in the Tödi area (Central Switzerland) 16.11.2012 Bern, Switzerland Rebetez Daniel; Ramseyer Karl;
SwissSed 2012 Poster The middle Triassic marine Transgression in the Tödi area (Central Switzerland) 25.02.2012 Fribourg, Schweiz, Switzerland Rebetez Daniel; Ramseyer Karl;


Associated projects

Number Title Start Funding scheme
113560 Early Triassic palaeotopography in Central Switzerland 01.05.2007 Project funding (Div. I-III)
149125 Early Triassic palaeotopography in Central Switzerland 01.03.2014 Project funding (Div. I-III)
113560 Early Triassic palaeotopography in Central Switzerland 01.05.2007 Project funding (Div. I-III)

Abstract

The reconstruction of the first marine transgression after the Hercynian orogeny in the Alpine region has fascinated geologists since the 18th century. Numerous efforts have been made to refine the stratigraphic allocation, depositional environment and paleogeographic position, but the lack of chronostratigraphic ages did not allow the reconstruction of the palaeorelief, the dynamics and the direction of the first marine transgression in Triassic times in Central Switzerland. Similarly, it is still unclear whether the basal Triassic in this part of the Alps is part of the Germanic Basin or belongs to the Tethys realm. The aim of this follow-up project is to reconstruct the depositional environments of the basal Triassic of Central Switzerland in a detailed chronological framework. This restoration will yield information for calculations of transgression rates, palaeorelief and palaeotopography at Early to Middle Triassic times, and for assignments of predominant controls during the transgression. The proposed project is designed for one PhD student who will study the Triassic sequences over a north-south distance of 100 km and an orogen-parallel distance of 75 km. At each selected localitiy detailed analyses of the facies, depositional surfaces, sedimentary structures, micro- and biofacies and stable isotopes will be undertaken. For each section palynologic analyses will be carried out to determine the ages of deposition. Based on this framework cyclo- and sequence-stratigraphic analyses of the sections will be carried out, which, will improve the chronological resolution of the Triassic sequences down to a 100 kyr resolution in some locations. Thus, it will become possible to attribute an exact duration for each order of depositional sequence, the transgression rate and the palaeorelief.The importance of the project lies in a high-resolution reconstruction of the dynamics controlling the Triassic transgression, which in turn will result in the estimation of the palaeotopography. If successful, our methodology can be applied to other cases where palaeosurfaces exist but where no information is available about paleorelief. These new insights will improve substantially the paleogeographic picture during Early to Middle Triassic in the Central Alps.
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