EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Transport of mafic magma through the crust and  sedimentary basins: Jameson Land, East Greenland

Christian Haug Eide1, Nick Schofield2, John Howell2, and Dougal Jerram3,4
Christian Haug Eide et al.
  • 1Department of Earth Science, University of Bergen, Box 7803, 5020 Bergen, Norway
  • 2School of Geosciences, Meston Building, University of Aberdeen, Aberdeen AB24 3UE, UK
  • 3Centre for Earth Evolution and Dymanics (CEED), University of Olso, Postbox 1028 Blindern N-0315 Oslo, Norway
  • 4DougalEARTH Ltd. Solihull, UK.

Igneous sheet-complexes transport magma through the crust, but most studies have focused on single segments of the magma-transport-system or have low resolution. In the Jameson Land Basin in East Greenland, reflection-seismic data and extensive outcrops give unparalleled constraints on mafic intrusions down to 15 km. This dataset shows how sill-complexes develop and how magma is transported from the mantle through sedimentary basins. The feeder zone of the sill-complex is a narrow zone below basin, where a magmatic underplate body impinges on thinned crust. Magma was transported through the crystalline crust through dykes. Seismic data and published geochemistry indicate magma was supplied from a magmatic underplate, without perceptible storage in crustal magma-chambers and crustal assimilation. As magma entered the sedimentary basin, it formed distributed, bowl-shaped sill-complexes throughout the basin. Large magma volumes in sills (4-20 times larger than the Skaergaard Intrusion), and few dykes highlight the importance of sills in crustal magma-transport. On scales smaller than 0.2 km, host-rock lithology, and particularly mudstone tensile strength-anisotropy, controls sill-architecture in the upper 10km of the basin, whereas sills are bowl-shaped below the brittle-ductile transition zone. On scales of kilometres and towards basin margins, tectonic stresses and lateral lithological changes dominate architecture of sills.

How to cite: Eide, C. H., Schofield, N., Howell, J., and Jerram, D.: Transport of mafic magma through the crust and  sedimentary basins: Jameson Land, East Greenland, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7207,, 2022.