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Stratigraphy, bathymetry and synsedimentary tectonics of the Early Jurassic of NW Switzerland

Reisdorf, Achim. Stratigraphy, bathymetry and synsedimentary tectonics of the Early Jurassic of NW Switzerland. 2017, Doctoral Thesis, University of Basel, Faculty of Science.

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Official URL: http://edoc.unibas.ch/diss/DissB_13453

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Abstract

The Early Jurassic full-marine sediments in NW Switzerland accumulated in the slowly subsiding area between the southwestern part of the Swabian Basin and the eastern Paris Basin. These deposits are dominated by fine-grained siliciclastics, but calcarenitic and phosphorite-rich strata are intercalated. Unlike in the adjacent regions of SW Germany and E France, they are arranged in a quite complex stratigraphic architecture characterised by rather abrupt facies changes, erosive truncations and gaps. Despite many common features in NW Switzerland, the sediments are considerably different with deposits of a similar age in SW Germany and E France that the definition of regional lithostratigraphic units is justified constituting the “Staffelegg Formation”. The Staffelegg Formation comprises 11 members and 9 beds. Several of these beds represent distinct correlation horizons. Some of them correspond to strata or erosional unconformities encountered in the Swabian realm, some of them can be correlated with strata in the Paris Basin.
The thickness of the Early Jurassic strata varies between 25 and 70 m. In the eastern and central parts of NW Switzerland, sediments Sinemurian in age constitute about 90% of the thickness. To the West, however, in the Mont Terri area, Pliensbachian and Toarcian deposits form 70% of the thickness. The accommodation space of the Early Jurassic strata was controlled mainly by eustatic sea-level changes. While eustatic sea-level rise was low, isopach maps having a chronostratigraphic resolution of one sub-stage provide clear evidence of differential subsidence as pre-existing faults in the basement that formed during the late Palaeozoic became reactivated. Orientation of relative thickness anomalies follow the fault trends either those of the Rhenish Lineament or those of the North Swiss Permocarboniferous Trough. Isopach anomalies are superimposed on a general trend of decreasing thickness to the South. Their small areal extension suggests that strike-slip movements occurred locally with a mosaic of basement blocks. Reactivation of faults in the basement during the Early Jurassic is also evidenced by temporally enhanced hydrothermal activity as documented by chronometric age of veins and mineral alterations.
Advisors:Wetzel, Andreas and Blau, J.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Ehemalige Einheiten Umweltwissenschaften > Sedimentology (Wetzel)
UniBasel Contributors:Reisdorf, Achim and Wetzel, Andreas
Item Type:Thesis
Thesis Subtype:Doctoral Thesis
Thesis no:13453
Thesis status:Complete
Bibsysno:Link to catalogue
Number of Pages:1 Online-Ressource (xviii, 105 Seiten)
Language:English
Identification Number:
Last Modified:16 Jan 2020 05:30
Deposited On:15 Jan 2020 14:23

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