I would like to thank Dr. A. Vollbrecht for his friendly advise, discussions and review of this Diploma thesis.
Thanks are also due to Prof. Dr. B. T. Hansen as the second reviewer.
I thank Dr. A. Vollbrecht, Dr. K. Wemmer, Dr. B. Leiss, Melanie-Viola von Drachenfels, Stefan Hoffmann, Torben
Seidel and former students for sharing their knowledge, field photos and photos of thin sections.
A special thank goes to Melanie-Viola von Drachenfels, Dominik Kirste, Steffen Grathwohl, Jutta Hoppe, Thorsten
Schulz and Thorsten Schocke for their companionship and encouragement during the last month.
I also thank Andreas Greiff, Dominik Kirste, and especially Christian Gross for proofreading my thesis and improving
my language skills.
Thanks to my family for encouragement and believing.