People at Fort Hoofddijk

Thomas Groenewegen
T.J. Groenewegen, BSc
Paleomagnetic Laboratory
Fort Hoofddijk
Department of Earth Sciences, 
Utrecht University 
Budapestlaan 17, 3584 CD Utrecht 
The Netherlands 

Phone +31 617434761


Research of Thomas Groenewegen

The geometry of the Central Iberian Arc: a combined paleomagnetic and structural approach

The Variscan Belt in Iberia draws an “S” shape double orocline. The northern orocline, the Cantabrian Orocline, is kinematically constrained as a secondary orocline and thought to be a thick-skinned feature. However, the geometry, kinematics and mechanism of formation of the southern orocline, the Central Iberian Orocline (CIO), are still unclear. Several geometries have been proposed for the orocline, most of them suggesting that the Morais allochtonous complex (NE Portugal) is in its core. We will combine structural geology and paleomagnetism in an attempt to solve the geometry of the CIO.

Arc geometry of the Cantabrian and Central Iberian oroclines

Paleomagnetic directions will be measured around the Morais allochtonous complex.
Sampled locations range from south of the complex to the east of the complex. The paleomagnetic directions will be combined with directions obtained from the structural analysis, to constrain whether the Morais Complex is indeed located in the hinge of the Central Iberian Orocline, or whether the hinge is located elsewhere.
The structural  geology will be the analysis of a road section to the south-east of the Morais allochtonous complex, in the hypothesized hinge zone of the orocline. The section consists of metasediments, where pelites are alternated with quartzites. 
Snake fold
Three major phases of deformation have formed a fold interference pattern and different generations of foliations. The relationship between the different deformation phases and their directional data will investigated.

Interesting structures showing a fold interference pattern which formed as the result of three major deformation phases. Supervisor for scale.

Left: making sketches and notes. Right: drilling of Cambrian limestones at the Tamames syncline.

publicationsPublications of Thomas Groenewegen