Basaltic traps and related intrusions, globally, host a variety of resources including aggregates (Mitchel, 2015), minerals (Lusty, 2017), geothermal (Campbell et al., 2016), and groundwater (Seneger et al., 2015; Babar and Muley, 2018). A detailed understanding of lava emplacement and stratigraphy can provide robust models to aid related resource management and sustainability. This project will focus on the stratigraphy and emplacement of the Antrim Lava Group, with implications and impacts that relate to the management and sustainability of related resources regionally and in similar geological settings worldwide.
During continental rifting that led to the opening of the North Atlantic ca. 56 Ma, the Antrim lavas erupted to form the basalt plateau in NE Ireland that includes the iconic Giant's Causeway UNESCO World Heritage site. Much work to date has focused on the petrology and geochemistry of the Antrim Lavas, resulting in a sophisticated understanding of the genesis and evolution of the basalt magma (Gamble et al., 1999). However, relatively little is known about the internal stratigraphy and spatial heterogeneity of the lava sequence. This gap in knowledge inhibits exploration for potential resources such as aggregates, subsurface geothermal sources, platinum group elements, rare metals and groundwater (Robins et al., 2011). The excellent exposure of the lavas, alongside an extensive set of cores and geophysical data, provide an as yet untapped opportunity to generate a high resolution reconstruction of lava emplacement.
This project's major work will involve analysis of 20 cores drilled across the plateau that penetrate the basalt sequence, plus 14 more logged boreholes (5 with geophysical logs), complemented by field sampling, collection and analysis of groundwater data, geological logging and mapping, augmented by a suite of laboratory analyses and subsequent modelling. In addition to stratigraphic analysis based on textural, petrological and geochemical characteristics (chemostratigraphy), the project will use magnetic analyses to aid stratigraphic interpretation (critically anisotropy of magnetic susceptibility (AMS) and palaeomagnetism). This will enable development of the most detailed model for the stratigraphy and emplacement of the Antrim lavas to date, improving our understanding of the volcanism that accompanied the rifting of the N. Atlantic, and generating one of the most detailed datasets worldwide that can be used to explore how magma productivity and effusive eruption frequency vary during rifting on kiloyear