CRUSTAL STRUCTURE OF THE LOFOTEN-MARGIN, N NORWAY, FROM NORMAL INCIDENCE AND WIDE-ANGLE SEISMIC DATA - A REVIEW

The crustal structure of the Lofoten continental margin, off Norway, h as been obtained from multichannel seismic reflection data and wide-an gle Ocean Bottom Seismograph (OBS) data. The shallow sedimentary seque nces on the shelf are well imaged on the seismic reflection data, wher eas deeper structures are mapped with confidence from the OBS-data. Th e area west of the shelf edge is covered with flood-basalts, associate d with the Paleocene/Eocene break-up between Norway and Greenland. The flood-basalts, which are essentially opaque on conventional multichan nel reflection data, can be penetrated with the OBS-method. A total th ickness of up to 4.0 km of pre-opening sediments is indicated below th e 1.0-2.5 km thick basalts. The crust is inferred to be of continental origin from the shelf to a sequence of seaward dipping reflectors (SD R) seaward of the Voring Escarpment (VE). Gradual decrease in crustal velocities from 'oceanic' beneath the SDRs to 'continental' at the Vor ing Escarpment is interpreted in terms of landward decrease in the con tent of magmatic intrusions in the crust, and the presence of a lower crustal magmatic body terminating close to the escarpment.