Royal Irish Academy Charlemont grant awarded to Dr Steven Hollis
Dr Steven Hollis (iCRAG Postdoc Research Fellow) has been awarded a Royal Irish Academy Charlemont grant for his project entitled 'Application of clumped C-O isotopes as vectors to Irish-type mineralization' in collaboration with the University of East Anglia.
In the 1950s Ireland had no active mining industry and seemingly few mineral prospects. Since the discovery of the Tynagh zinc-lead deposit in 1961, five orebodies have been mined and over twenty sub-economic prospects discovered. By 2007, Ireland was annually producing ~38% of Western Europe’s zinc and 25% of its lead. Carbonate-hosted Zn-Pb deposits have become the mainstay of the Irish mining industry, with over 30 companies actively exploring for mineral deposits in well constrained Lower Carboniferous host sequences.
With the closure of the Lisheen mine of county Tipperary in 2015, there is now a sense of urgency to understand the complex fluid-mixing processes during Zn-Pb mineralization, and to identify criteria that will lead to the discovery of new economic resources. Only one mine in Ireland remains operational - the giant Navan deposit of county Meath. Irish deposits are currently being mined faster than new resources are being discovered. With over 580 employees, Navan is Europe’s largest Zn mine (2.2 Mt of ore produced in 2015 - approximate value €287mn at current metal prices) with a life of 7 years unless new resources are found. Hopes for a restored Irish mining industry rest on Navan and the so-far, undeveloped Pallas Green prospect. According to the Fraser Institute, Ireland is currently the 4th top jurisdiction in the world for mining and first for policy perception from 109 competing jurisdictions. The closure of the Navan mine would mean crucial skills would be lost from Ireland, with reduced investment by exploration companies due to a perceived lack of prospectivity.
There is now a consensus that Irish-type Zn-Pb deposits are mainly epigenetic ores formed by the replacement of Lower Carboniferous limestones. Conditions required for their formation include dense networks of normal faults that allowed ascending, warm, metal-bearing fluids equilibrated with Lower Palaeozoic basement to mix with sinking, cooler, hypersaline brines that carried bacteriogenically reduced sulphide of ultimate seawater origin. Our research bridges the gap between academia and industry, and includes the novel application of clumped C-O isotopes to Irish Zn-Pb deposits in order to understand fluid sources, temperatures of carbonate precipitation during mineralization, fluid-mixing processes, and isotopic halos surrounding orebodies.
Through funding from the Royal Irish Academy, the researcher will conduct a three-week visit to the University of East Anglia to help refine the clumped C-O isotope technique with leading scientists in this field, and further apply it to the world class Navan deposit.
More information on Charlemont grants can be found here.
(News Item Image Credit: UCD PhD student Aileen Doran)