Seismic interpretation and gravity modelling of BIRPS SWAT lines 5 and 6

Seismic interpretation of the British Institutes Reflection Profiling Syndicate (BIRPS) seismic reflection lines SWAT 5 and 6 was carried out and a time section showing the major reflective horizons drawn up. This section was depth converted and where possible geological ages given to the sedimentary reflectors and densities assigned to the geological bodies. Using a computer gravity modelling program the theoretical and observed gravity anomalies were compared and some slight modifications were made to the models to enhance agreement between the two. The models indicate that the lower crust may have a higher density in the north, suggesting that there may be a boundary between two crustal blocks at the north end of the SWAT 6 profile. It is also tentatively suggested that the Haig Fras batholith was injected from below whereas the Cornubian Batholith may have been intruded from the south.