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

Igneous sheet-complexes transport magma through the crust, but most studies have focused on single segments of magma-transport-system or low resolution. In Jameson Land Basin in East Greenland, reflection-seismic data and extensive outcrops give unparalleled constraints mafic intrusions down to 15 km. This dataset shows how sill-complexes develop is transported from mantle sedimentary basins. The feeder zone sill-complex a narrow below basin, where magmatic underplate body impinges thinned crust. Magma was crystalline crust dykes. Seismic published geochemistry indicate supplied underplate, without perceptible storage crustal magma-chambers assimilation. As entered it formed distributed, bowl-shaped throughout basin. Large volumes sills (4-20 times larger than Skaergaard Intrusion), few dykes highlight importance magma-transport. On scales smaller 0.2 km, host-rock lithology, particularly mudstone tensile strength-anisotropy, controls sill-architecture upper 10km whereas are brittle-ductile transition zone. kilometres towards basin margins, tectonic stresses lateral lithological changes dominate architecture sills. Supplementary material: https://doi.org/10.6084/m9.figshare.c.5670470