Response of the landscape in the Swiss Alps to the late glacial to Holocene climate transition [Elektronische Ressource] / von Kevin Patrick Norton

Kevin Patrick Norton

Informations

• Publié par: gottfried_wilhelm_leibniz_universitat_hannover
• Publié le: 01 janvier 2008
• Nombre de lectures: 59
• Langue: English
• Poids de l'ouvrage: 16 Mo

Extrait

Response of the landscape in the Swiss Alps to the late
glacial to Holocene climate transition




Von der Naturwissenschaftlichen Fakultät der
Gottfried Wilhelm Leibniz Universität Hannover
zur Erlangung des Grades eines
DOKTORS DER NATURWISSENSCHAFTEN
Dr. rer. nat.







genehmigte Dissertation
von
M. Sc. Kevin Patrick Norton
geboren am 13.03.1974 in Springfield, Ohio
2008



















Referent: Prof. Dr. Friedhelm von Blanckenburg
(Leibniz Universität Hannover)

Korreferent: Prof. Dr. Fritz Schlunegger
(Universität Bern)

Tag der Promotion: 14.08.08










Erklärung zur Dissertation
Hierdurch erkläre ich, dass die Dissertation selbständig verfasst und alle benutzten
Hilfsmittel sowie evtl. zur Hilfeleistung herangezogene Institutionen vollständig
angegeben habe. Die Dissertation wurde nicht schon als Diplomarbeit oder ähnliche
Prüfungsarbeit verwendet.



Hannover, den 12.06.2008

Kevin Patrick Norton














“Climb the mountains and get their good tidings”
-John Muir





















Acknowledgements

First and foremost, this work would not have been possible without Friedhelm von
Blanckenburg who was willing to take a chance on me. I could not have asked for a better
advisor. Thank you for taking the time to not only listen, but to respond as well (even when
you were too out of breath to do so). Thanks as well to the von Blanckenburg family for
more than just a room.

Fritz Schlunegger has been unflagging in his support of my work. Sampling in the Napf
would not have been possible without his expertise. The Uni Bern group, in general has
become a second home (quite literally in Luca’s case!).

I would like to thank Andreas Mulch for convening my defense, and the Geology Department
in general for allowing me to work in their labs.

Danke auch alle im Geochemie Arbeitskries in Hannover. I’ve enjoyed spending the last few
years with all of you. Hella Wittmann helped me learn the chemisty and didn’t mind the
noodles too much. I am also indebted to Sonja Zink and Kirsten Möller for helping with
translation at short notice, and Jane Willenbring for helping review this manuscript! I am
fortunate to have overlapped with Veerle Vanacker for a few months in Hannover. She has
been there for me in the field, in the lab, in the office, and in general.

Thanks to Andrea Hampel who was just as excited about glacio-isostatic uplift as I was, and
who did the finite-element modeling.

Thank you to Peter Burgath and Antje Wittenberg at the BGR who organized the XRF
measurements.

Also, a big thanks to everyone at the Institute for Particle Physics at ETH Zurich, and
especially Peter Kubik. I greatly enjoyed sitting in the control room, and I now know much
more about AMS than I ever thought I would.

I want to thank all of the students who at least pretended to listen to me both in the classroom
and in the mountains. I probably learned more than you did. Sabine Schwienbacher did most
of the dirty work in the lab and deserves my thanks and a coffee.

My Saturdays would have been much less exciting without Ronny and Ilka Schoenberg,
Merci vielmals.

Jérôme Chmeleff and Severine Moune were instrumental in keeping me sane and happy even
when far away.

My family, Nortons and Dahls alike, have been vital in keeping me going over the years.

I am a functional human being because of my Mother, Bethany McDonald. She spent many
years as a superhero, and continues to ply her trade, accompanied by Louie, wherever she
goes.

Finally, and with all sincerity, I would like to thank my wife, jenny dahl. My work has been
supported by many people along the way. My life has been supported by you. Thanks.
CONTENTS

Abstract...………………………………….…………………………………………………..i
Zusammenfassung…………………....................……………………………………………..v

1. Introduction …………………………………………………………………………………1
1.1.Motivation……..……………………………………………………………………..……1
1.2. A brief introduction to the Geology and Geomorphology of the European Alps…..……2
1.3. Organization of the dissertation………….………..……………………………..……….3

2. Grid sizes effects on topographic shielding calculations.…………….…………………….5
Abstract…......………………………………………………………..………………….…….5
2.1. Introduction……………………………………………………………………………….6
2.1.1. Applications of in-situ produced cosmogenic nuclides ...………………………………6
2.1.2. Cosmogenic nuclide production and shielding ...………………………………………6
2.1.3. Topographic scaling in geomorphology ..………………………………………….…..7
2.2. Materials and methods ..………………………………………………………………….9
2.2.1. Topographic shielding……..…………..………………………………………………..9
2.2.2. Topographic metrics…………………………………………………………………...10
2.2.3. Data sources and terrain smoothing ...............................……………………………...11
2.3. Results and discussion ..………………………………………………………………...13
2.3.1. Shielding at the basin scale……………………………………………………………13
2.3.2. Shielding estimates depend on grid size ..…………………………………………….14
2.3.3. Decrease of shielding estimates with grid size depends on terrain roughness.………..16
2.3.4. Is there an ideal grid size for measuring topographic shielding? ……………………. 18
2.3.5. When does grid size matter? ………………………………………………………….21
2.4. Conclusion …………………………………………………………………………….21

3. Landscape transience in the Swiss Mittelland…………………………………………….23
Abstract………………………………………………………………………………………23
3.1. Introduction……………………………………………………………………………...24
3.2. Geologic and geomorphologic setting…………………………………………………...26 3.3. Methods………………………………………………………..……………………….29
3.3.1. Site selection… ………………………………………………………………………29
3.3.2. Morphometrics…… ………………………………………………………………….30
3.3.3. Cosmogenic nuclides………………………………………………………………….32
3.4. Results .....………………………………………………………………………………34
3.4.1. Morphometrics ...……………………………………………………………………..34
3.4.2. Cosmogenic nuclides……….…………………………………………………………36
3.5. Discussion……………….………………………………………………………………37
3.5.1. Landscape evolution…………………………………………………………………...37
3.5.2. Soil production..................…………………………………………………………….38
3.5.3. Incision and disequilibrium……………………………………………………………39
3.6. Conclusions ..….….. ……………………………………………………………………40

4. Hillslope process rates in the upper Rhone valley.. .…………………………………….43
Abstract..…………………………………………………………………………………….43
4.1. Introduction…..…………………………………………………………………………43
4.2. Setting...…………………………………………………………………………………44
4.3. Methods..………………………………………………………………………………..47
4.4. Results...…………………………………………………………………………………48
4.5. Discussion…….…………………………………………………………………………49
4.6 Conclusions ……..………………………………………………………………………52

5. Chemical and physical controls on weathering in Alpine terrains...………………………55
Abstract....……………………………………………………………………………………55
5.1. Introduction...……………………………………………………………………………55
5.1.1. Geomorphic setting……………………………………………………………………57
5.2. Sampling and Methodology..........………………………………………………………61
5.3. Results…………………………….……………………………………………………..63
5.4. Discussion……………………………………………………………………………….64
5.4.1 Controls on chemical weathering rates…..…………………………………………….64
5.4.1.1. Geomorphic controls…………………….…………………………………………..66
5.4.1.2. Lithological controls………………….……………………………………………..67
5.4.1.3. Effects of vegetation…………………….…………………………………………..68 5.4.1.4. Temperature controls ………..……………………………………………………..69
5.4.2. Weathering in the Holocene…………………………………………………………..70
5.4.3. Relationship between physical and chemical weathering ..…………………………..72
5.5. Conclusions……………………………………………………………………………..72

6. Glacier response to glacioisostatic rebound.…………………………...…………………75
Abstract……..………………….…………….………………………………………………75
6.1. Introduction…………….……………….……………………………………………….75
6.1.1. Equilibrium line altitude discrepancies ………………………………………………..77
6.2. Finite-element modeling…………………………………………………………………78
6.3. Results…………………………………………………………………………………...80
6.4. Conclusion……………………………………………………………………………….83

References Cited………………………………….…………………………………………..84

Appendix 1. Cosmogenic nuclides: theory and methods…………………………………….99
A1.1. Production rates ………………………………………………………………………100
A1.2. Calculation of denudation rates ………………………………………………………108
A1.3. Basin-averaged denudation rates……………………………………………………..110
10A1.4. Determining burial ages with Be…………………………………………………...112
A15. Topographic shielding of cosmic rays……..…………………………………………112
A1.6. Cosmic ray shielding by snow……………………………………………………….114
A1.7. Field and Laboratory methods……………………………………………………….116
A1.8. Step-by-step laboratory procedure…………………………………………………...123

Appendix 2. Chemical weathering rates: t