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Name: Dónal Ó ’ Farrell

Contact Details

Tel: +353 (0)1 896 1440
Fax: +353 (0)1 6711199
Email: dofarre@tcd.ie

Title of Project

Halogens in the Proto- Iceland Plume Source Mantle

Project details

The apparent decoupling of lithophile radiogenic isotope (Sr-Nd-Pb) systems from noble gas isotopic systems implies the existence of a less degassed and possibly primitive volatile reservoir that has remained isolated from the convecting mantle for more than 3 billion years. 3He is considered a primitive noble gas which likely emanates from the original solar nebula.  Lavas which mark the onset of the Iceland mantle plume contain the highest 3He/4He ratios ever recorded in a terrestrial lava sample (up to 50 Ra).

The objective of this study is to characterise the elemental (F, Cl, Br, I) and isotopic (d37Cl) halogen composition of these lavas which are derived from the less degassed 3He volatile reservoir. Halogen geochemistry has allowed for unique insights into volatile cycling in the Earth’s mantle.

This work will combine a range of analytical techniques including FTIR (Fourier Transformation Infrared Spectroscopy) and ion microprobe analysis to be carried out at the NordSIMS facility in Stockholm, Sweden.

Name of supervisors

Dr Emma Tomlinson - Trinity College Dublin
Dr John Caulfield - Trinity College Dublin

Demonstration/Teaching

I supervise some of the 1st year lab tutorials in the module GL1101: Junior Freshman Geology

Postgraduate personal details

I graduated from Trinity College Dublin in 2015 with a B.A. Mod in Geology. My undergraduate dissertation involved 6 weeks of mapping of the Ordovician and Silurian volcanic successions at Lough Nafooey in county Mayo. During the Summer months of 2015 I carried out a student internship with Teck Ireland who are actively involved with Lead and Zinc exploration in the Irish midlands.

Project Start Date

October 2015


Last updated 29 January 2016 nmcginle@tcd.ie.