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Relative dating activity uio as


The geodynamic history of a region is archived in its geologic record which, in turn, may reflect deformation patterns that causally can be related to certain configurations of paleostresses. In the Oslo Region, the exposed geological record ranges from Precambrian high-grade metamorphic rocks Relative dating activity uio as Cambro-Silurian sedimentary rocks to Permo-Carboniferous sedimentary and magmatic rocks, the latter being related to the development of the Oslo rift system.

We investigate the kinematics of outcrop-scale faults to derive the diversity of paleostress states responsible for the observed strain.

For this purpose, we combine Relative dating activity uio as graphical and numerical approaches to separate heterogeneous fault-slip data sets and estimate the associated reduced stress tensors.

The present study gives evidence for three major regional paleostress fields that affected the Oslo Region: For a large number of estimated stress states, none of the principal axes are sub-vertical. The present study tends to show that the Oslo Region remained unaffected by major tectonic activity for much of the Mesozoic and Cenozoic — which is when the Central European Basin System to the south experienced several phases of intense deformation. The Oslo Rift is the northernmost part of the Rotliegendes basin system in Europe.

The rift was formed by lithospheric stretching north of the Tornquist fault system and is related tectonically and in time to the last phase of the Variscan orogeny.

The main graben forming period in the Oslo Region began in Late Carboniferous, culminating some 20—30 Ma later with extensive volcanism and rifting, and later with uplift and emplacement of major batholiths.

It ended with a final termination of intrusions in the Early Triassic, some 65 Ma after the tectonic and magmatic onset. We divide the geological development of the rift into six stages. Sediments, even with marine incursions occur exclusively during the forerunner to rifting.

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The magmatic products in the Oslo Rift vary in composition and are unevenly distributed through the six stages along the length of the structure. The presence or absence of a thermally anomalous mantle plume during the formation of the widespread Carboniferous—Permian magmatism of northern Europe is examined. Both tholeiitic and alkaline magmas have diverse trace element compositions. The tholeiites have a "Relative dating activity uio as" affinity to E-MORB but have mixed with variable amounts of lithosphere and upper crust.

Tectonic reorganisation and decompression melting of a trace element-enriched mantle is considered to have controlled the Carboniferous—Permian magmatism, which contains no coherent geochemical evidence for a single plume-related thermo-chemical anomaly.

Utover i permtiden ble en riftdal dannet med strekking av jordskorpa og store forkastninger. This study focuses on Late Carboniferous - Permian tectonics and related magmatic activity in north-western Europe, and specifically in the Skagerrak, Kattegat and North Sea areas. A large database consisting of seismic and well data has been assembled and analysed to constrain these objectives. The continuation of the Oslo Graben into the Skagerrak has been a starting point for this regional study.

Rift structures with characteristic half-graben geometries and the distribution of magmatic rocks intrusives and extrusives were mapped using integrated analyses of seismic Relative dating activity uio as potential field data.

The rift structures in the Skagerrak can be linked with extensional structures in the Sorgenfrei-Tornquist Zone in which similar fault geometries have been observed. Both in the Skagerrak and the Kattegat, lava sequences were deposited which generally parallel the underlying Lower Palaeozoic strata.

This volcanic episode therefore, predates main fault movements and the development of half-grabens filled with Permian volcaniclastic material. Especially in the latter area, the dense seismic and well coverage has allowed us to map out similar Upper Palaeozoic geometries, although the presence of salt often conceals the seismic image of the underlying strata and structures. From the results, it is assumed that the pre-Jurassic structures below large parts of the Norwegian-Danish Basin and northwards into the Stord Basin on the Horda Platform belong to the same tectonic system.

One of the main goals of this project was to produce a new map for this time period showing the distribution of Late Carboniferous — Early Permian Lower Rotliegend volcanics, dykes and sills and the extent of the tectonic structures of the Early — Late Permian Upper Rotliegend sedimentary basins better known as the Southern and Northern Permian Basins.

In order to produce this map, an overview of all the available literature was made. The new map was completed based on our own interpretations from seismic and borehole data. Unpublished data were available through industrial partners associated with the PCR-project.

The Permo-Carboniferous evolution of the central North Sea is characterized by three main geological events: The timing of the late Carboniferous - Permian basaltic volcanism in the North Sea is Relative dating activity uio as constrained, as is the timing of extensional tectonic activity following main inversion during the Westphalian due to the propagation of the Variscan deformation front. The presence of volcanics below the dated horizon, suggests that the onset of Permo-Carboniferous volcanism in the central North Sea commenced earlier, probably at c.

This is contemporaneous with other observations of tholeiitic volcanism in other parts of NW Europe, including the Oslo Graben, the north-east German Basin, southern Sweden and Scotland. Interpretations of available seismic data show that main extensional faulting occurred after the volcanic activity, but the exact age of the fault activity is difficult to constrain with the data available.

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