Analog modeling of one-way gravitational spreading of hot orogens - A case study from the Svecofennian orogen, Fennoscandian Shield

摘要

Geodynamic models offer insight into deformation styles of syn- and post-collisional extensional processes. Such models often ignore the effect of lateral viscosity contrast between accreted terranes and inherited tectonic boundaries. This paper presents a set of crustal-scale analog experiments of one-way post-collisional gravitational spreading testing the effect of crustal heterogeneity by using two mechanically contrasting blocks, pre-existing cuts with varying dips, and three layers with contrasting rheologies. Two blocks represent strong, mature, and weak, juvenile crustal parts. Both blocks have three horizontal crustal layers: brittle upper, weak partially molten middle and dry strong lower layer. Cuts represent pre-existing crustal-scale shear zones and tectonic boundaries.