The Influence of Crustal Structure and Multiphase Magmatism on the Evolution of the Hatton Rifted Continental Margin, Offshore Ireland, Using Seismic Reflection and Potential Field Methods

The Hatton Basin is located next to the continent-ocean boundary in the Irish offshore, east of the Hatton passive volcanic Continental Margin. It is bounded by the Rockall Bank to the east and by the Hatton High to the west. Little is known about its structure and evolution within the context of the North Atlantic opening, given the lack of modern geophysical data.

Here we use modern multichannel seismic (MCS) data acquired with a 10km-long streamer, together with DSDP data and potential field data to explore the formation processes of this basin. The MCS and DSDP data combined with analogues from the Rockall, Porcupine and Slyne-Erris basins suggest the presence of Mesozoic (possibly Jurassic) to Holocene sediments. The seismic data indicates that one major syn-breakup, and some minor post-breakup magmatic phases influenced the evolution of the Hatton Basin. Evidence of magmatic activity in the basin consist of multiphase sill intrusions, formation of paleo-volcanic cones at different stratigraphic levels and deformation of post-breakup strata above some volcanoes observed on the MCS lines.

Both magnetic and gravity data show NNE-SSW trending lineaments of positive anomalies, extending from the center of the basin towards the southern end. The locations of the mapped paleo-volcanoes in the basin are spatially coincident to these anomalies. The connection between the paleo-volcanoes and potential field anomalies reflect areas with stronger magmatic influence, which is also supported by potential field modelling applied to the 2D seismic profiles. Magnetic and gravity modelling showed that the existence of the NNE-SSW trending anomalies cannot be explained by shallow magmatic intrusions observed on the seismic reflection data, indicating that the anomalies represent deep-seated features in the basin. In order to fit the potential field data observed along the seismic reflection profiles, magmatic intrusions in the middle crust had to be introduced into the 2D models.

This publication has emanated from research supported in part by a research grant from Science Foundation Ireland (SFI) under Grant Number 13/RC/2092 and co-funded under the European Regional Development Fund and by PIPCO RSG and its member companies.