| dc.description.abstract | Gothenburg Energy, SGU, and Gothenburg University are investigating the possibility for
geothermal energy plant in the Gothenburg area. A 1 km drill core were drilled in the Högsbo
area and two bachelor thesis were written by Julia Ladefoged and Anna Hynynen about the
first 550 m of the core. These theses discussed the structural and petrological aspects of the
rock in the core. This thesis together with Glamheden (2022) has documented the structural
and petrological aspects of the last 450 m.
When comparing data from Ladefoged (2021) and the data collected for this thesis, a couple
of foliation sets were found. The foliation sets from this thesis point towards the southwest,
west, and southeast, with some measurements pointing south. Ladefoged (2021) two sets
points towards northwest and southeast and north to south. Veins have an orientation towards
southwest, northeast, north, and south with a varying dip between 20 – 40°. The number of
veins is slowly increasing towards the end. Fractures have a very scattered orientation but
have some stronger ones towards the southwest and northeast. Fractures and veins increase
with depth while the rock strength decreases. This could be because of a nearby fault zone or
an increase in cross-cutting fracture sets. Two hypotheses could be drawn from this research.
One includes three deformation events spanning between the Gothian orogeny and the
Caledonian orogeny, and one that only contains two deformation events spanning between the
Gothian orogeny and the Sweconorwegian orogeny.
Fieldwork was conducted at Änggårdsbergen in Gothenburg. The result showed that the area
has an orientation towards the southwest and is gently plunging and steeply inclined.
Comparing the field data with the data from the core show two possible scenarios. One
scenario is that the area was created during the Sweconorwegian orogeny by rotating the folds
from the Gothian orogeny by 108° anti-clockwise and got a 2° change in the plunge. This
would lead to a broader set of fractures. The other scenario does the same as the first but
rotates the position of the fold after the Sweconorwegian orogeny by 28° clockwise and got a
1° change in the plunge during the Caledonian orogeny leading to smaller sets of fractures.
Three big fracture sets could be found throughout Änggårdsbergen with clar notation of
058/55, 240/55, and 137/90. However, more data is needed to draw any final conclusions
about whether it is possible and suitable to build a geothermal plant in the Högsbo area. | en_US |
