Proposed Mesozoic dykes in the Celtic Sea

A swarm of dykes 56 km long and 2.5 km broad cutting the Haig Fras granite batholith and the surrounding country rock is proposed from interpretations of magnetic, bathymetric and seismic surveys. A model of the magnetic anomaly consists of six vertical bodies, three of which have reversed magnetisation and three weaker, normal magnetisation. Each body may consist of many dykes. Only a Mesozoic age is consistent with the structural setting, strike and magnetic properties of the porposed dykes, and they may be part of a phase of intrusion dated elsewhere between 200 Ma and 110 Ma

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