Project title: North Atlantic basement terrane correlation based on K-feldspar Pb isotope mapping with applications in sedimentary provenance and mineralisation
Researcher: Dr Ezster Badenszki
This project aims to reconstruct the disposition of tectonic terranes in the North Atlantic region during three supercontinental cycles, based on Pb isotope mapping, a technique that is primarily utilised in sedimentary provenance studies. Sedimentary provenance studies of sandstone reservoirs contribute significantly to reservoir characterisation and correlation. During iCRAG1, Pb isotopic analysis of detrital K-feldspar was extensively applied to sedimentary provenance studies of Irish offshore basins (e.g., Franklin et al. 2019, 2020), where a major source of K-feldspar is inferred to come from Precambrian granitic rocks. The former sediment pathways drawn from such studies, and thus the presence and quality of reservoirs in Ireland and adjacent regions is, however, open to interpretation. This is because the isotopic characterisation of the Precambrian source units is far from adequate. By compiling and/ or determining the isotopic compositions from a suite of Precambrian rocks from Ireland, Scotland, Fennoscandia, Greenland, and Labrador (including samples from offshore exposures and drill core), provenance models can be better evaluated. Carbon dioxide storage greatly benefits and relies on detailed studies of sandstone reservoirs. Sedimentary provenance studies provide a detailed temporal and spatial characterisation of the reservoir rocks and create models that can contribute to the selection of suitable sub-surface carbon dioxide storage reservoirs. This also plays a critical role in the implementation of the emissions reductions agreed by Ireland (among other countries) under the Paris Agreement.
Demand for certain metals, such as vanadium, lithium, cobalt, and rare earth elements has dramatically increased in response to the demand for low carbon energy sources and battery storage. Within this context, new deposits of these metals are sought alongside a reevaluation of known occurrences. Several concentrations of these deposits are known or in prospect in basement regions around the North Atlantic, particularly in S Greenland (e.g. Gardar Province within the Ketilidian mobile belt and the adjacent North Atlantic Craton). J. S. Daly is currently working with two Irish companies in this region who are evaluating a vanadium deposit and simultaneously investigating the CO2 sequestration potential of pulped silicate gangue minerals, which will otherwise have to be disposed of as waste. More generally, there is an increasing appreciation recently of the role of ancient plate boundaries/ lithospheric discontinuities in controlling mineralisation. Hence, an anticipated contribution of this project is that it will not only provide a basis for the distribution of these major mineral deposits, but also the framework for understanding how and when they formed. Reconstructing ancient palaeogeography, constraining major terranes, and discriminating large-scale lithospheric boundaries through isotopic mapping is a proven technique, which has the capacity to contribute to both of these aspects of Challenge 2.