Navan (Tara)
County Meath (Irish Midlands), Irlande
Mississippi Valley TypeZn-Pb
- Type
- Carbonate-hosted Zn-Pb (Irish type)
Europe's largest Zn-Pb deposit, hosted in Navan Group limestones. Irish-type Zn-Pb deposits formed at about 350 to 340 Ma by replacement of Lower Carboniferous carbonates, through mixing of a deep metal-bearing fluid (170 to 240 °C) with a brine rich in bacterial sulfide. Sphalerite δ66Zn, unrelated to temperature, increases from feeder veins to late orebodies: kinetic fractionation during rapid precipitation, or mixing of two sources. Mine coordinates.
δ66Zn in ‰ (per mil) Values of the same system
Standard : JMC 3-0749L, IMC 12053 Zn
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 0.02 ‰ | 1 | orebody sphalerite One analysis, Table 1. Precipitation at about 150 °C. | Wilkinson et al. (2005), Zinc isotope variation in hydrothermal systems: preliminary evid… | |
| −0.09 ± 0.19 ‰ | −0.32 / 0.23 ‰ | 21 | colloform sphalerite of the 5 lens, successive microdrilled bands Mean and standard deviation recalculated from 21 microdrilled bands, Table 2. Five samples (D1 to D5). Up to 0.33 ‰ variation over 3 mm of growth: kinetic fractionation during rapid precipitation. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
| 0.01 ± 0.08 ‰ | −0.08 / 0.08 ‰ | 4 | mine ore concentrates (U and 1 lenses) Mean and standard deviation recalculated from 4 samples, Table 2. Represent the bulk of the deposit, close to the basement. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
| 0.11 ± 0.1 ‰ | −0.02 / 0.23 ‰ | 6 | lower Palaeozoic basement rocks (altered schist, mudstones, pyroclastic rock, agglomerate, volcanogenic sediment) Mean and standard deviation recalculated from 6 samples, Table 2. Probable zinc source. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
δ56Fe in ‰ (per mil) Values of the same system
Standard : IRMM-014
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −1.27 ± 0.66 ‰ | −2.11 / −0.14 ‰ | 19 | colloform sphalerite of the 5 lens, successive microdrilled bands Mean and standard deviation recalculated from 19 microdrilled bands, Table 2. Correlated with δ66Zn (R2 = 0.78). | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
| −0.57 ± 0.09 ‰ | −0.7 / −0.51 ‰ | 4 | mine ore concentrates (U and 1 lenses) Mean and standard deviation recalculated from 4 samples, Table 2. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
| 0 ± 0.12 ‰ | −0.18 / 0.11 ‰ | 6 | lower Palaeozoic basement rocks (altered schist, mudstones, pyroclastic rock, agglomerate, volcanogenic sediment) Mean and standard deviation recalculated from 6 samples, Table 2. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
δ34S in ‰ (per mil) Values of the same system
Standard : V-CDT
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −1.1 ± 8.2 ‰ | −9.5 / 14.6 ‰ | 16 | colloform sphalerite of the 5 lens, successive microdrilled bands Mean and standard deviation recalculated from 16 in situ analyses, Table 2. Positive values (hydrothermal sulfur) go with light zinc and iron, negative values (bacterial sulfur) with heavier ones. The two D5 values (-9.2 and -13.2 ‰), taken from Barrie et al. (2009), are not counted. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
| 8.4 ± 5.7 ‰ | 2 / 13 ‰ | 3 | galena of the 5 lens Mean and standard deviation recalculated from 3 in situ analyses, Table 2. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
| −8.9 ± 4.1 ‰ | −11.7 / −2.8 ‰ | 4 | mine ore concentrates (U and 1 lenses) Mean and standard deviation recalculated from 4 samples, Table 2. Mainly bacterial sulfur. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
206Pb/204Pb isotope ratio, no unit Values of the same system
Standard : NIST SRM 981
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 18.197 ± 0.003 | 18.194 / 18.201 | 5 | sphalerite of the 5 lens Mean and standard deviation recalculated from 5 samples, Table 2. Only 206Pb/204Pb is published. Homogeneous lead, identical to lead concentrates (18.19): no source mixing. | Gagnevin et al. (2012), Zn, Fe and S isotope fractionation in a large hydrothermal system… |
Deposits of the same type
- Irish Midlands Zn-Pb prospects and basement veins Irlande
- Galmoy Irlande
- Lisheen Irlande
- Tynagh Irlande
- Silvermines Irlande
- Kilbricken Irlande
- Sheshodonnell Irlande
- Cloghatrida (Rathkeale) Irlande
Cite this page
IsoFind Atlas (2026). Navan (Tara), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/navan-tara/ (accessed 2026-10-13).
@misc{isofind2026navantaraisotopesignatures,
title = {Navan (Tara), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/navan-tara/},
note = {Accessed 2026-10-13}
}Updated : 2026-10-13