EUROBRIDGE'95: deep seismic profiling within the East European

• Main Authors: Yliniemi, J., Tiira, T., Luosto, U., Komminaho, K., Giese, R., Motuza, G., Nasedkin, V., Jacyna, J., Seckus, R., Grad, M., Czuba, W., Janik, T., Guterch, A., Lund, C.E., Doody, J.J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2001
• Subjects: Crustal structure; Fennoscandia
• Online Access: http://lmavb.lvb.lt/LMAVB:ELABAPDB5091182&prefLang=en_US

Lower crust exhibits velocities of commonly 6.5-6.9 km/s, and thickens to the south-cast with P-wave velocities up to 7.0 km/s in the deepest parts. Crystalline crust is characterised by low velocity gradients and small velocity contrasts at most seismic boundaries. Major lateral changes in crustal velocity structure atall depths can be spatially correlated with the WLG-EL boundary determined from near surface geological information. Very strong reflections from the Moho boundary are observed. The mantle P-wave velocity immediately below the crust is 8.2- 8.35 km/s. A reflector in the lower lithosphere at a depth of almost 70 km was found below Lithuania. Reflectivity modelling of the Gotland shot data suggests that this interface is absent offshore, where mantle velocities are lower. The DSS model supports the interpretation of the WLG and EL as terranes of Proterozoic age forming part of Fennoscandia. Later modification of crustal structure may have occurred, possibly by a mantle-heating episode centred on the Baltic Sea area. (C) 2001 Elsevier Science B.V. All rights reserved.