Structure of the Hatton Basin and adjacent continental margin

Abstract

In the summer of 2002, new data were acquired along wide-angle and normal-incidence profiles extending from the Hatton Basin, across the adjacent Hatton Bank volcanic continental margin and into the Iceland Basin. Eighty-nine four-component ocean-bottom seismometers (OBS) were deployed along a transect running across the continental margin and along two strike lines located above the region of thickest extrusive and intrusive igneous rock on Hatton Bank and over 44 Ma oceanic crust near the end of the main dip profile. The seismic profiling was optimized for large offset OBS arrivals with a low-frequency airgun source centred at 10 Hz. Wide-angle seismic energy penetrated the extruded basalt, the underlying crust and well into the upper mantle. Initial modelling results from Hatton Basin show a ∼4 km thick sedimentary sequence and provide a new sub-sediment crustal thickness estimate of ∼15 km. This crustal thickness suggests a stretching factor of two relative to the continental crust under Rockall Bank. These new results have been integrated with an established model for the region to demonstrate the variations of crustal structure across the margin. Future processing and modelling of the extensive dataset collected in the 2002 survey will allow refinement of the crustal structure model across the stretched continental crust beneath Hatton Basin and the adjacent continental margin. In particular it will place better constraints on the intrusive and extrusive igneous components produced during continental break-up in the Palaeogene.