Starting September 2014, PhD student Chen Chen and post-docs Louise Watremez and Manel Prada (DIAS, Dublin) are working together to define the crustal structure across Porcupine Basin, which is located offshore SW Ireland. The degree of crustal thinning increases from North to South, allowing us to observe the structures of the crustal thinning at different stages of the extension. During the M61/2 cruise, more than 10 thousand refraction shots were recorded by an array of ocean-bottom seismometers and land seismometers, along 5 transects. First of all, the analysis of these data will allow us to image the crustal structure of Porcupine Basin. Then, we should also be able to define the nature of a deep-structure that is identified as the Porcupine Median Ridge and of which the nature has been discussed a lot in the past three decades (continental rocks, volcano or serpentinite?). Finally, some sills have been detected across the basin. The analysis of the arrivals corresponding to these structures will hopefully allow us to define the position of these sills in the sediment cover as well as their number and lateral extension.

Author: Louise Watremez