Structural evolution of Zn-Pb deposits of south-central Ireland; with particular reference to Galmoy, Silvermines and Tynagh



Duration - 01/10/2002 - 30/09/2005

Funding - Basic Research Grant from IRCSET (Irish Research Council for Science, Engineering and Technology), the Irish Government body for funding basic research

Research Partners

Introduction
The Lower Carboniferous of Ireland is host to many base metal deposits which together constitute one of the world’s major Zn-Pb orefields. The origin and evolution of these mineral deposits has been the subject of much research over the past few decades. Several contrasting models have been proposed for the formation of these deposits, though they all recognise that faults play a fundamental role, acting as the main conduits for transporting mineralising ore fluids and also providing the main bounding structures to the deposits.

Objectives
The principal objectives of this project are to better understand the structural geology and the main structural controls on Zn-Pb deposits of south-central Ireland. These objectives will be fulfilled by completing the basic aims of the project, as follows:

  1. To establish quantitative constraints on the 3-D geometry and kinematics of normal fault arrays within the Lower Carboniferous limestones of the south-central Midlands of Ireland.
  2. To define the 3-D geometry and growth of normal fault-related structures such as relay ramps, normal drag and spatially associated breccias.
  3. To define the principal structural controls on the location of mineral deposits and the relative timing of structures to mineralisation.
  4. To define the nature, extent and timing of inversion-related structures.
  5. To refine kinematic structural models for both the formation and the inversion of Zn-Pb mineral deposits.

Technical components
The 3 main analytical and modelling components of this project are:


Our analysis and modelling will be constrained principally by: (i) underground mine data from Galmoy Mine, (ii) archive data for Silvermines and Tynagh Mines (stored by the Geological Survey of Ireland) and (iii) regional and archive geological and geophysical datasets. It is anticipated that the project will also benefit from the generic findings of an existing PhD project on the Lisheen deposit, which is planned to be completed one year into this 3 year project.

Expected results
The successful completion will provide:

  1. A structural model for the Zn-Pb mineral deposits of south-central Ireland, incorporating both the relative timing and growth of all of the main structural elements observed within these deposits.
  2. A model for the main structural controls on the formation of Zn-Pb deposits in south-central Ireland.



Contact: Chris Bonson or John Walsh
Tel: +353 1 716 2169
Email