Oxygen and Hydrogen Isotope Geochemistry of the Mourne Mountains Tertiary Granites, Northern Ireland

McCormick, A. G.; Fallick, Anthony E.; Harmon, Russell S.; Meighan, I. G.; Gibson, David

doi:10.1093/petrology/34.6.1177

Cited by 10 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…along structural features in the western Mournes correlate with vein mineralisation resulting from episodic migration of hydrous fluids of variable composition, probably with a smaller magmatic component than elsewhere. This finding is compatible with previous research that used stable isotope compositions to show that meteoric fluids have a minor and localised influence on granitic rocks near internal contacts and at the margins of plutons (McCormick et al, 1993).…”

Section: A Tellus-based Critical Metals Surveysupporting

confidence: 92%

A natural laboratory for critical metals investigations in the Mourne Mountains granites

Moore

Moles²,

Lusty

2016

Unearthed

View full text Add to dashboard Cite

Certain metals that are vital for many modern technologies occur naturally in the Mourne Mountains Complex of County Down, Northern Ireland. These include niobium, tantalum and the rare earth elements. Using the Tellus geochemistry data and the results of more detailed sampling, we have investigated their geological sources in granite bedrock and their dispersion in stream sediments. From this research, an exploration methodology has emerged that can assist in the search for critical metals globally. Planned follow-on studies include investigations of the environmental fate of these metals and the potentially toxic elements with which they are naturally associated. Strategic contextMany new technologies, such as those required for clean energy generation and modern communications, require a wide range of elements in their manufacture. Of particular interest are elements that are used in small quantities but are highly valued for their unusual properties. The mines that produce these economically important metals are mostly located in a few countries where political, social and environmental circumstances could potentially disrupt supply. These technology metals with a substantial supply risk are termed 'critical metals' (Moss et al., 2011). The rare earth elements (REEs) exemplified the concept of criticality when in 2011 China, which controlled 97% of the global REE supply, cut its export quota and caused a shortfall in supply relative to demand (Chakhmouradian and Wall, 2012).Supply shortages cannot be fully offset by increased recycling due to dispersion of critical metals in the environment, longevity of use in some applications, and manufacturing design and alloying with metals that inhibit separation (Steinbach and Wellmer, 2010;Bloodworth, 2014). Other mitigation strategies include substitution, reduction in use

show abstract

Section: A Tellus-based Critical Metals Surveysupporting

confidence: 92%

A natural laboratory for critical metals investigations in the Mourne Mountains granites

Moore

Moles²,

Lusty

2016

Unearthed

View full text Add to dashboard Cite

show abstract

“…Stable isotope analysis from the Mourne Mountains granite shows that influxes of meteoric waters were restricted to the margins of the pluton and internal contacts (McCormick et al 1993). High-salinity Type 4 inclusions in the Mourne Mountains granites are associated with these locations, and may reflect the local influx of surface-derived fluids which circulated through overlying evaporitic deposits.…”

Section: Origin Of Type 2 and Type 4 Fluidsmentioning

confidence: 97%

Fluid inclusions in Irish granite quartz: monitors of fluids trapped in the onshore Irish Massif

Conliffe

Feely

2010

Earth and Environmental Science Transactions of the Royal Socie

View full text Add to dashboard Cite

Fluid inclusion studies of granite quartz provide an opportunity to study fluid flow associated with igneous activity and post-emplacement fluid processes. This study presents new fluid inclusion data from the late Caledonian Donegal granites and Newry granodiorite, and the Tertiary Mourne Mountains granite in Ireland, which identify three distinct fluids. Aqueous-carbonic fluids (Type 1) have been recorded in late Caledonian granites with a significant mantle component (Newry granodiorite and the Ardara and Thorr granites in Donegal). These fluids represent late-magmatic fluids trapped at high temperatures (up to 575°C), and the ultimate source of these carbonic fluids is linked to sub-lithospheric processes during the Caledonian orogeny. The dominant fluid type (Type 2) in late Caledonian granites is a H2O+NaCl±KCl fluid which may be related to thermal convection cells around granite bodies and/or to regional scale influx of surface derived fluids at the end of the Caledonian orogeny. High salinity NaCl–CaCl2 fluids (Type 3) overprint quartz in the Ardara granite in Donegal, and in the Newry granodiorite, and are interpreted to represent basinal brines, sourced in overlying sedimentary basins, which circulated through the crystalline basement during a period of crustal extension (possibly during the Carboniferous or the Triassic). Fluid inclusion studies of the Tertiary Mourne Mountains granites have identified only Type 2 fluids related to thermal convection cells, consistent with stable isotope evidence, which indicates that this younger granite is unaffected by regional-scale fluid influxes.

show abstract

“…Tertiary igneous complexes relating to the rifting of North America and Eurasia and the opening of the Atlantic Ocean are present in north-east Ireland (Jolley and Bell, 2002;Stevenson and Bennett, 2011). The vast basaltic lavas of Co. Antrim date to this period (Lyle, 1980;Lyle and Preston, 1993), whilst the Mourne granites of Co. Down were also emplaced at this time (McCormick et al, 1993;Stevenson and Bennett, 2011).…”

Section: Post-variscanmentioning

confidence: 98%

The genesis of gold mineralisation hosted by orogenic belts: A lead isotope investigation of Irish gold deposits

et al. 2014

View full text Add to dashboard Cite

Lead isotope analyses have been performed on 109 gold and 23 sulphide samples from 34 Irish gold occurrences, including 27 placers, and used to shed light on the sources of mineralising fluids and metals associated with gold mineralisation hosted by orogenic belts. The Pb isotope ratios of lode and placer gold range from 206 Pb/ 204 Pb = 17. 287-18.679, 207 Pb/ 204 and 208 Pb/ 204 Pb = 37.517-38.635, consistent with the Pb isotopic data on previously reported Irish sulphide mineralisation. There is no evidence that gold mineralisation is associated with distinctive source regions, and it appears to have been derived from similar sources to those responsible for the widespread sulphide mineralisation in Ireland. It is inferred that the principal controls on the Au mineralisation are structural and not related to the distribution of Au in their source rocks. The range of Pb isotope ratios favours the interaction of multiple source reservoirs predominantly during the Caledonian Orogeny (c.475-380 Ma). Underlying basement was the primary control on two key sources of Pb. Gold occurrences located to the south-east of the Iapetus Suture are characterised by Pb compositions that derive predominantly from the Late Proterozoic crustal basement or overlying Lower Palaeozoic sediments, whilst those located north-west of the Iapetus Suture are characterised by less radiogenic Pb signatures derived predominantly from Late Proterozoic or older crustal basement. A third source, relatively enriched in radiogenic Pb, also played a role in the formation of a number of Irish gold occurrences, and may have been associated with syn-to postorogenic intrusives. Magmatic processes may therefore have played an important role in the formation of some gold occurrences located in orogenic settings.

show abstract

Oxygen and Hydrogen Isotope Geochemistry of the Mourne Mountains Tertiary Granites, Northern Ireland

Cited by 10 publications

References 0 publications

A natural laboratory for critical metals investigations in the Mourne Mountains granites

A natural laboratory for critical metals investigations in the Mourne Mountains granites

Fluid inclusions in Irish granite quartz: monitors of fluids trapped in the onshore Irish Massif

The genesis of gold mineralisation hosted by orogenic belts: A lead isotope investigation of Irish gold deposits

Contact Info

Product

Resources

About