Dr. Michael Stock

Critical-Ireland aims to place fundamental new constraints on the thermodynamic and fluid mechanic processes that generate magmatic platinum group element (PGE) deposits. Due to their essential role in green technologies and concerns over supply security, PGEs constitute 'critical raw materials' which require innovative research to identify new deposits. The Palaeogene igneous intrusions in Ireland have been suggested as one of the most prospective regions for PGE mineralisation in Europe and excellent bedrock exposure, combined with new GSI Tellus data, make them an ideal natural laboratory for investigating PGE mineralising processes. Critical-Ireland will apply state-of-the-art petrographic and geochemical techniques to Palaeogene igneous complexes in Ireland, determining how the dynamics of magma assimilation impact sulphide solubility in mafic intrusions, and how country rock contamination, sulphide accumulation and PGE enrichment vary as a function of thermal and fluid dynamic regime along magma conduits. These new constraints will be used to inform the first dynamic numerical models of PGE mineralising processes, which will aid in understanding deposit formation globally. Critical-Ireland will bring together a unique international research team to place first-order constraints on magmatic processes, which will aid in securing the European PGE supply and unlocking Ireland's potential to produce critical raw materials.

Dynamic processes operating within crustal magma systems control the composition, style and timing of volcanic eruptions at the Earth's surface. For over a Century, our conceptual understanding of magma system architectures has centred around "magma chambers" - isolated bodies of liquid rock, hosted within the solid crust beneath a volcano. However, volcanology is currently undergoing a paradigm shift, whereby this simple model of magmatic systems is being called into question. Rather than discreet bodies, geological datasets are increasingly converging on a new "transcrustal mush zone" model of magma system architecture, where magmas are stored throughout the entire crust beneath a volcano but are largely in a solid-dominated (mush) state. Liquid melts only occupy the pore space between crystals and small melt-rich pockets (sills that are 100s m long and 10s m thick). These mush zones have different physical/chemical properties to magma chambers surrounded by solid rock, impacting the processes operating during magma ascent, and necessitating re-evaluation of our understanding of magmatic processes and eruptions triggers. Although interactions between ascending magmas and mush must affect volcanism at the Earth's surface, linking these processes is difficult due to a paucity of suitable study sites. This project will investigate interactions between ascending magmas and mush before recent eruptions of Campi Flegrei caldera (Italy). Recent Campi Flegrei eruptions have covered a diversity of styles and compositions, and the volcano has been identified as hosting a transcrustal mush-type magmatic system. Specifically, the project will: . Develop an innovative method integrating geochemical data, thermodynamic models and statistical techniques to quantify the amount of mush which has been disaggregated and incorporated into ascending magmas. . Undertake a multidisciplinary study of minerals in eruption deposits, applying geochemical and textural analyses to identify mush-derived crystals and using these to constrain the mush rheology. . Apply state-of-the-art petrological models to understand the depths and timescales of magma storage, integrating these with geophysical datasets to construct a comprehensive picture of the Campi Flegrei magmatic system. The project will have broad scientific impact, addressing major outstanding questions in our understanding of how dynamic processes within transcrustal mush zones impact the composition and style of volcanism at the Earth's surface. As Campi Flegrei is one of the most hazardous volcanoes on Earth and is showing significant signs of unrest, the project also has major societal significance; working with the INGV Vesuvius Observatory, the results will be integrated into volcano monitoring efforts, improving hazard assessment and civil protection.

Continental rifting is one of the principal events which reshape the Earth's surface over timescales of hundreds of millions of years. These rifts are frequently associated with mantle plumes (upwelling areas of hot mantle) and, in combination, these two processes thin the Earth's crust and heat it, leading to prodigious magma generation. This gives rise to huge outpourings of lava at the surface, as well as associated intrusive rocks in the crust, and is known as Large Igneous Province (LIP) volcanism. This volcanism may cause major climate change due to carbon dioxide release and have been implicated in multiple mass-extinctions. Rifting of the North Atlantic during the breakup of the supercontinent Pangaea produced such a LIP, due to the influence of the mantle plume which is currently located beneath Iceland. The LIP volcanism that formed above this plume during progressive opening of the Atlantic is currently exposed in: the counties Antrim and Armagh in Northern Ireland; the islands of Rum, Mull, Eigg, Arran and the peninsula around Ardmamurchan in Scotland; the Faroe Islands; and parts of Iceland and Greenland. The Northern Irish volcanics of the Antrim Lava Group are particularly important, as they appear to be among the earliest manifestations of the LIP volcanism and relatively unpolluted by incorporation of crustal rocks during their eruption. However, they remain the least researched, with only a handful of studies in the past thirty years. This project will apply a full range of modern geochemical techniques to the Irish volcanic rocks to identify changing conditions in the mantle (e.g. temperature, melting depth and composition) during the rifting of the North Atlantic. These are not only crucial pieces of information for understanding the history of this major tectonic event in Earth history, but also how LIP volcanism develops more generally.

In 2019, Trinity College Dublin and Geological Survey Ireland launched the Earth Surface Research Laboratory (ESRL): a new national facility providing state-of-the-art chemical analyses for the geoscience community on the island of Ireland. The laboratory hosts world-class facilities for the preparation and analysis of geological and environmental samples. Ireland has a fascinating and diverse geology, formed over millions of years through the eruption of volcanoes, the opening and closing of oceans, the slow erosion of towering mountain ranges and finally, the recent glacial events that shaped our landscape. These geological processes have endowed the country with economically important mineral deposits and fertile soils which support a thriving agricultural industry. However, to fully understand Ireland's geological heritage and sustainably harness its natural resources, we need to know more than the simple distribution of different rock types - we need to know exactly what the rocks are made of, right down to individual elements. The ESRL hosts a range of advanced equipment to interrogate the geochemistry of rocks and soils. This includes two X-ray fluorescence spectrometers, which can precisely determine elemental abundances down to trace concentrations, an Hg-analyser for specifically determining the abundance of mercury in environmental samples, and an elemental analyser for quantifying organic and inorganic carbon. These instruments are housed within clean rooms to prevent contamination and are supported by expert technical staff. The laboratory supports Geological Survey Ireland's Tellus geochemical survey - a major national programme to map elemental concentrations in soils, stream sediments and stream waters across Ireland. It is also open to academic researchers, SMEs and other geological/environmental groups based on the island of Ireland in a non-commercial capacity. The facilities enhance the world-class geoscience research conducted on the island of Ireland and assist projects protecting Ireland's unique natural environment. The ESRL was recently awarded a prestigious ISO 17025:2017 Accreditation For Calibration and Testing Laboratories by the Irish National Accreditation Board (INAB). This internationally recognised certificate allows the laboratory to analyse Government samples for use in policymaking, legal cases and commodity profiling, where traceability and data quality are paramount.

Critical metals are a vital resource for high technologies and green energy production, but their occurrences in Ireland are poorly constrained. The Mourne Mountain Complex (MMC) is a subalkaline igneous suite prospective for critical metals, including rare earth elements (REE) and high field strength elements (HFSE). However, no detailed studies on the MMC or its critical metal occurrences exist, partly due to the complex's rugged nature. This project aims to analyse samples from the MMC using hyperspectral analyses with the Geological Survey Ireland's hyperspectral scanner and to identify the causes for the hyperspectral signatures using geochemical analyses at the Earth Surface Research Laboratory (ESRL) in TCD and the National Centre for Isotope Geochemistry (NCIG) in UCD. The results of these analyses will then be checked against remote sensing data from the ASTER data sets released by NASA with the ultimate goal of synthesising a geologic map using hyperspectral remote sensing data. The hyperspectral and geochemical databases, methodologies and techniques for ASTER data reduction, and creation of a critical metal prospectivity map for the MMC are expected to provide valuable information for future researchers and government agencies and to encourage interest by private industry for Irish critical metals.