A laccolith intruded into a basaltic lava flow succession in eastern Iceland

Description
This model shows a 250×120 m wide area, characterized by a horizontal lava succession (cropping out especially to the right side) intruded by a 18-m-thick, doleritic laccolith (e.g. Pasquarè and Tibaldi, 2007; Tibaldi et al., 2008); see country house for scale. The shallow magma body is distinguished by thick columnar joints: most are vertical but, on the right hand side (SE), they bend and attain a gentler dip. Some are slightly curvilinear. On the righy-hand side (SE) of the area, the lava succession is intruded by a vertical, N10°-trending, 7-m-thick dyke. The site is located in eastern Iceland, whitin Tertiary age units; further details on the dykes and geology in eastern Iceland can be found in Walker (1974), Gudmundsson (1983), Jóhannesson and Sæmundsson (1998) and Gudmundsson et al (2014).

Credits: UAV-based survey and 3D DOM provided by Fabio L. Bonali, Federico Pasquaré Mariotto and Elena Russo; funding is from MIUR project ACPR15T4_00098 (http://argo3d.unimib.it/). Model description by Alessandro Tibaldi and Federico Pasquaré Mariotto.

References

• Gudmundsson, A. (1983). Form and dimensions of dykes in eastern Iceland. Tectonophysics, 95(3-4), 295-307.
• Gudmundsson, A., Pasquarè, F., Tibaldi, A. (2014). Dykes, sills, laccoliths, and inclined sheets in Iceland. In Physical Geology of Shallow Magmatic Systems (pp. 363-376). Springer.
• Jóhannesson, H., & Sæmundsson, K. (1998). Geological map of Iceland, 1: 500,000. Bedrock Geology. Natturufraedistofnun Islands, Reykjavik.
• Pasquarè, F., & Tibaldi, A. (2007). Structure of a sheet-laccolith system revealing the interplay between tectonic and magma stresses at Stardalur Volcano, Iceland. Journal of Volcanology and Geothermal Research, 161(1-2), 131-150.
• Tibaldi, A., Vezzoli, L., Pasquaré, F. A., & Rust, D. (2008). Strike-slip fault tectonics and the emplacement of sheet-laccolith systems: the Thverfell case study (SW Iceland). Journal of Structural Geology, 30(3), 274-290.
• Walker, G. P. (1974). The structure of eastern Iceland. In Geodynamics of Iceland and the North Atlantic area (pp. 177-188). Springer, Dordrecht.