IGA Lecture: Dr. Peadar McArdle (Geological Survey Of Ireland)

Peering into the depths! The geology of Fogo Island, Newfoundland.

Fogo comprises a composite granite-gabbro intrusion which has been emplaced along the bedding of its host rocks. This stratiform magma chamber is 7km thick and tilted on its side, so that its contents are well exposed. It was the very hot gabbro magma which melted the lower crust to produce granitic magma, and both magmas travelled upwards along seismically-active fractures in small batches. The pluton was formed by incremental assembly over an extended time period, its upper part composed of granite and the lower of gabbro. The landscape of Fogo has been scoured by ice sheets so that its bedrock is well exposed and it illustrates some modern concepts of igneous intrusion.

on the following dates nationwide:

December 3rd (Cork),
December 10th (Dublin),
December 11th (Galway).

Bettie Higgs will be organising the Cork venue in University College Cork, and Fiona Stapleton will be organising Galway at University College Galway.

The Dublin venue will be the usual Geological Survey of Ireland at Beggars Bush (Dublin 2) at 6:30 pm, with coffee and biccies at 6:00 pm.

Peadar McArdle is a UCD graduate who completed his PhD on mineralisation associated with the Leinster Granite. Following work in the minerals industry, Peadar had an extended career in the Geological Survey of Ireland, from which he retired as Director in 2010.