Data from: Zircon U-Pb emplacement ages of intrusions in the Mary Kathleen Domain, Mount Isa Inlier, Australia

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Abstract [extract from related publication]: The Mary Kathleen Domain (MKD), within the Mount Isa Inlier, Queensland, hosts numerous occurrences of Cu ± Au mineralisation, which are spatially associated with igneous intrusions. However, the temporal relationships between the emplacement (crystallisation) ages of these intrusions and important mineralisation events remains ambiguous in many cases. This is further complicated by secondary overprinting of primary magmatic rocks (and mineralisation) during later metamorphic or hydrothermal events, which can potentially reset datable mineral archives. Here we present 29 new U-Pb zircon ages for magmatic intrusions from across the MKD, which are all interpreted as emplacement ages. Our results, combined with previous data, show that most intrusions in the MKD were emplaced during at least four discrete periods of magmatic activity between c. 1880 Ma and c. 1500 Ma; these are the Kalkadoon Igneous Province (c. 1860 Ma), Argylla Igneous Province (c. 1780 Ma), Wonga-Burstall Igneous Province (c. 1760-1710 Ma), and the Williams Igneous Province (c. 1550-1500 Ma). Limited geochronology data on ore mineralisation associated with intrusions within the MKD suggests that most mineralisation formed coeval with the emplacement of the Williams Igneous Province, however intrusions of this province are not exposed throughout much of the MKD. This dataset suggests that any mineralisation interpreted to be originally sourced from MKD intrusions that are older than c. 1550 Ma has likely been remobilised or modified by younger events, in cases where the ore mineralisation ages reported are much younger than the magmatic emplacement ages. The results also highlight the need for detailed mapping and investigations of field relationships between different magmatic phases and with the surrounding country rock to resolve geologic history and stratigraphic succession ambiguities some area within the MKD.

Zircon grains were analysed in the Advanced Analytical Centre, James Cook University, for cathodoluminescence (CL) and laser-ablation inductively coupled mass spectrometry (LA-ICP-MS). The zircons were imaged using a Jeol JSM5410LV with attached CL detector to identify zoning within zircon grains. Suitable zircons were analysed for U-Th and Pb isotopes (along with Si, Ti, Fe and Zr) with a GeoLas 200 Excimer Laser Ablation System in a He ablation atmosphere, coupled to a Thermo Scientific iCAP RQ ICP-MS. Data was processed using Iolite 4 (U-Pb geochronology DRS; Paton et al., 2011).

This data record contains:

One Excel file containing U-Pb zircon data. Dataset includes values for the following headings: 207Pb/235U; 2SE propagated error; 206Pb/238U; 2SE propagated error; 207Pb/206Pb; 2SE propagated error; rho (207/235 206/238); rho (206/238 207/206); mean U/Th; 207Pb/206Pb age; 2SE propagated error; x is >5% discordance; x is >10% discordance