Geometric modeling (GOCAD) of the marginal zone of two neighboring laccoliths and the interstitial host sediments based on well data (eastern Halle Volcanic Complex, Late Paleozoic)

(bachelor thesis 2012)

The project provides a geometric visualization for a part of the underground of the Halle Volcanic Complex (HVC) located in the northeastern area of the city Halle/Saale. The data used for this model originates from 63 bore logs drilled in the 20th century during exploration projects for coal and uranium (Wismut GmbH) as well as projects to confirm the drainage system in this area. Evidenced were two laccolith units (Landsberg and Brachstedt laccolith) and the occurrence of sediment intercalations in the marginal zones of these intrusions. The geometric distribution of those sediment intercalations of the Halle-Formation and Wettin-Subformation sediments was visualized by GOCAD (Geological Object Computer Aided Design). The Landsberg laccolith seems to have developed different auxiliary intrusions initiated by fractures in the roof of the laccolith during the process of dooming. Those auxiliary intrusions are thought to have used pathways (fractures) in the host-sediments to tilt and lift them up. The process progressed until an enclosure of those sediments from the Wettin-Subformation and Halle-Formation was complete. This possible evolution leading to this current appearance was compared and discussed with other recent models from Hutton (2009) and Horsman (et al., 2010) to provide further details for the emplacement of laccoliths and the development of their marginal zones.

Halle Volcanite Complex

3D model of the Halle Volcanite Complex: green- Landberg rhyolith; yellow- Brachstedt rhyolith; red- Halle Formation; grey- Wettin sub-Formation; blue- Seimic lines.

Team

  • Tobias Schmiedel
  • Prof. Ch. Breitkreuz
  • Dr. B.-C. Ehling