Research Output
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Publication
Clumped C-O isotope temperature constraints for carbonate precipitation associated with Irish-type Zn-Pb orebodies
2017-08-23, Hollis, Steven P., Menuge, Julian, Doran, Aileen, Güven, John, et al.
Ireland hosts the greatest concentration of discovered zinc per square kilometre on Earth, with production from 5 carbonate-hosted deposits, including the giant Navan deposit. Clumped C-O isotope analyses of carbonates offer a powerful new technique to directly deliver accurate fluid temperatures and precise calculations of fluid O isotope compositions, offering a significant opportunity to refine the evolving genetic models, and develop new vectoring tools for exploration. We present the first clumped C-O isotope results for parageneticallyconstrained carbonate generations from a number of Irishtype Zn-Pb deposits. Preliminary analysis of hanging-wall white matrix breccias from Lisheen show non-systematic temperature variation (~100 to 170°C), with fluid d18OV-SMOW increasing with temperature. Significant variations in temperature at the thin section scale may be indicative of fluid mixing and/or multiple phases of WMB dolomite brecciation. Post-ore pink dolomite at Lisheen, and crosscutting calcite veins formed at significantly lower temperatures (67 to 42°C). Temperatures of 61 to 110°C were obtained for sphalerite-bearing calcite veins in the hanging-wall of the Randalstown Fault near Navan. These veins contain coarse sphalerite interpreted to have been remobilised from the nearby Navan orebody by a single, cool fluid (Marks, 2015). Clumped C-O data will also be presented for samples from Galmoy, Kilbricken and Castlegard ("Pallas Green"), from which existing fluid inclusion constraints are available.
Publication
Clumped C-O isotope temperature constraints for carbonate precipitation associated with the Irish-type Lisheen and Navan Zn-Pb orebodies
2017-04-03, Hollis, Steven P., Menuge, Julian, Dennis, Paul, Doran, Aileen, Güven, John, et al.
Mineral C-O isotope values are controlled by crystallization temperature and the isotopic
composition of the fluid.
Publication
Constraining fluid mixing processes at the Irish-type Lisheen and Navan Zn-Pb orebodies: preliminary evidence from clumped C-O isotopes
2016-09-04, Hollis, Steven P., Menuge, Julian, Dennis, Paul, Güven, John, et al.
Our research has applied the clumped O-C isotope technique to the Irish Zn-Pb ore field. Preliminary clumped C-O data will be presented from the Lisheen Zn-Pb orebody (22.3 Mt mined at 11.7% Zn and 2.0% Pb) [4] along with fluid inclusion data . Samples were analysed from all main carbonate generations across the deposit , including: regional dolomite (D 1), dark grey to black pre-ore hydrother mal dolomite (D 2 ; also known as black-matrix breccia), medium-to-coarse-grained ore-stage white ferroan dolomite (D 3 ; white-matrix breccia) , late veins of ferroan dolomite (D4) and white calcite (C4), post-ore crosscutting pink saddle dolomite (D 5), and post-ore white blocky calcite (C 6). We will discuss existing metallogenetic models for the Lisheen deposit and the potential for clumped C-O analysis to constrain fluid flow pathways and mixing processes, and as a tool for mineral exploration .
Publication
A comparison between clumped C-O and fluid inclusion temperatures for carbonates associated with Irish-type Zn-Pb orebodies
2017-08-12, Hollis, Steven P., Doran, Aileen, Menuge, Julian, Güven, John, et al.
Ireland hosts the greatest concentration of discovered zinc per square kilometre on Earth, with past and current production from five Irish-type carbonate-hosted deposits, including the giant Navan deposit. Clumped C-O isotope analysis of carbonate phases offers a powerful new technique to deliver accurate fluid temperatures and fluid O isotope compositions, refining evolving genetic models and developing new tools for exploration.