TY - THES

T1 - Sedimentological, biostratigraphical and diagenetic studies on Hallstatt Mélanges in the Dinarides and the Northern Calcareous Alps

AU - Stanzel, Anna

N1 - embargoed until null

PY - 2015

Y1 - 2015

N2 - The Dinaric Ophiolite Belt in the Zlatar Mountains displays a complex geological setup. Its examination is crucial for the reconstruction of the evolution of the Alpine-Carpathian-Dinaride mountain belt. It comprises a carbonate-clastic mélange that is overthrusted by an ophiolitic mélange and topped by ophiolites. The carbonate-clastic mélange, also referred to as Hallstatt Mélange, was studied in terms of provenance, composition and age at the site of Vodena Poljana. The blocks as well as the matrix were dated, which led to an improved understanding of the evolution and the tectonic history of the Dinarides. The mainly Triassic olistolithes are chaotically embedded in a Middle Jurassic radiolaritic matrix. This Triassic components reveal an origin from Neotethys distal passive margin. During the Middle Jurassic, westward ophiolite stacking of the Neotethys Ocean floor and finally obduction onto the Dinaric continental margin occurred. Simultaneously the ophiolitic mélange and later the carbonate clastic mélange were formed. The carbonate clastic mélange is interpreted to represent the synorogenic trench-fill in front of the advancing nappe stack. The sedimentological and biostratigraphical results of this thesis further support the evolution described above. The other main purpose of this thesis was to investigate a possible correlation between the Conodont Colour Alteration Index (CAI) and the Quartz Crystallinity Index (QCI) for the temperature range 50°C to 200°C. Due to the fact that hardly any data exist about the grade of diagenesis in Western Serbia, analogues in the Northern Calcareous Alps are used. Most samples derive from the Strubberg Formation, part of the Hallstatt Mélange, of similar age and composition, unlike the mélange in Vodena Poljana. QCI were calculated from radiolarites and compared to published CAI zones. The QCI values show a clear relationship with these zones. Various influencing factors and possible sources of errors of this method are discussed. Finally, the economic significance of siliceous rocks in general and the use of the QCI are presented within this thesis.

AB - The Dinaric Ophiolite Belt in the Zlatar Mountains displays a complex geological setup. Its examination is crucial for the reconstruction of the evolution of the Alpine-Carpathian-Dinaride mountain belt. It comprises a carbonate-clastic mélange that is overthrusted by an ophiolitic mélange and topped by ophiolites. The carbonate-clastic mélange, also referred to as Hallstatt Mélange, was studied in terms of provenance, composition and age at the site of Vodena Poljana. The blocks as well as the matrix were dated, which led to an improved understanding of the evolution and the tectonic history of the Dinarides. The mainly Triassic olistolithes are chaotically embedded in a Middle Jurassic radiolaritic matrix. This Triassic components reveal an origin from Neotethys distal passive margin. During the Middle Jurassic, westward ophiolite stacking of the Neotethys Ocean floor and finally obduction onto the Dinaric continental margin occurred. Simultaneously the ophiolitic mélange and later the carbonate clastic mélange were formed. The carbonate clastic mélange is interpreted to represent the synorogenic trench-fill in front of the advancing nappe stack. The sedimentological and biostratigraphical results of this thesis further support the evolution described above. The other main purpose of this thesis was to investigate a possible correlation between the Conodont Colour Alteration Index (CAI) and the Quartz Crystallinity Index (QCI) for the temperature range 50°C to 200°C. Due to the fact that hardly any data exist about the grade of diagenesis in Western Serbia, analogues in the Northern Calcareous Alps are used. Most samples derive from the Strubberg Formation, part of the Hallstatt Mélange, of similar age and composition, unlike the mélange in Vodena Poljana. QCI were calculated from radiolarites and compared to published CAI zones. The QCI values show a clear relationship with these zones. Various influencing factors and possible sources of errors of this method are discussed. Finally, the economic significance of siliceous rocks in general and the use of the QCI are presented within this thesis.

KW - Dinaric Ophiolite Belt

KW - Zlatar Mountains

KW - Hallstatt mélange

KW - ophiolitic mélange

KW - carbonate-clastic mélange

KW - Vodena Poljana

KW - Strubberg Formation

KW - radiolarite

KW - radiolarians

KW - Triassic radiolarite

KW - Jurassic radiolarite

KW - Neotethys

KW - Quartz Crystallinity

KW - Quartz Crystallinity Index

KW - diagenesis

KW - Hallstatt Mélange

KW - Dinarischer Ophiolith Gürtel

KW - ophiolithische Mélange

KW - karbonat-klastische Mélange

KW - Vodena Poljana

KW - Zlatar Gebirge

KW - Strubberg-Formation

KW - Radiolarien

KW - Radiolarit

KW - triassischer Radiolarit

KW - jurassischer Radiolarit

KW - Neotethys

KW - Quartz Crystallinity Index

KW - Quarz Kristallinität

KW - Diagenese

M3 - Master's Thesis

ER -