Abstract -
Faults and fracture systems are the most important store and pathway for groundwater in Ireland’s bedrock aquifers either directly or where they provide conduits that control bedrock dissolving groundwater and therefore form loci for the development of karst. This poster briefly outlines a new project on the quantitative analysis of fault and fracture systems in the broad range of Irish bedrock types, focussing on developing generic conceptual models for fault/fracture systems in different lithologies and at different depths, and linking them to observed groundwater behaviour. The project will define the quantitative characteristics of the different types of fault/fracture systems encountered in Ireland. A variety of attributes/parameters, all of which are critical determinants of the flow behaviour and pathways of such systems, will be defined from high quality natural outcrops, quarries and mines, including fracture orientations, densities, spacing/clustering, sizes (length/aperture/thickness), scaling and connectivity. Quantitative characteristics of the different fault/fracture systems will be defined in distinctive lithological sequences (e.g. Calp or Waulsortian limestones), in an attempt to provide a mechanical basis for differing fracture system systematics and established differences in the flow and transport conceptualisations across Irish fractured bedrocks, and their variations either in depth or across regional zones. Structural geologic conceptual models and parameterisations will be linked to observed groundwater behaviour (derived from GSI hydrogeological databases and on-going Griffith and EPA-Strive projects) by undertaking flow simulation of simple generic fracture system models and case studies of flow in Irish fractured aquifers.
Abstract of poster presented at:
International Association of Hydrogeologists, Irish Group - 32nd Annual Groundwater Conference, Tullamore, April 2012.