Geology of Sligo-Leitrim - Sheet 7

                                                                                                                                                                                                                                                           1:100,000 series index

Area covered by the Map and Booklet

Area covered by map



Booklet Contents

  • PREFACE
  • LANDSCAPES AND GEOLOGY
  • THE GEOLOGICAL MAP OF SLIGO-LEITRIM
  • A SUMMARY OF THE GEOLOGICAL HISTORY AND ROCK TYPES OF SLIGO-LEITRIM
    • Metamorphic rocks of the Ox Mountains and Rosses Point inliers
    • Lower Palaeozoic and Devonan sedimentary rocks
    • Carboniferous (355- about 310 million years ago
    • Post Carboniferous events
    • Quaternary geology (the Ice Age and Recent)
    • THE EARTH RESOURCES OF SLIGO-LEITRIM
      • Industrial minerals
      • Coal and hydrocarbon deposits
      • Metallic deposits
          • HYDROGEOLOGY
          • THE BEDROCK GEOLOGY OF SLIGO-LEITRIM
            • Pre-Dalradian basement or Dalradian: Slishwood Division
            • Dalradian Supergroup
            • Callow Succession (Dubiously Dalradian, possibly Cambro-Ordovician)
            • Cloonygowan Formation (Cambro-Ordovician)
            • Deer Park Complex (Cambro-Ordovician)
            • Structure, deformation and metamorphism of the Ox Mountain Inlier
            • Regional metamorphism of the central Ox Mountains
            • Ordovician
            • Silurian
            • Igneous intrusions
            • Suspect terranes
            • Devonian
            • Carboniferous
                • References and additional reading list
                • Appendix 1. Simplified descriptions of rock units
                • Appendix 2. Glossary of technical terms

                  • Two plates from the booklet:

                    This photograph shows part of a huge boulder which lies just to the east of the upper part of the "circular" forest walk north of the car park at Slish Wood. It shows typical gneisses of the Slish Wood Division.

                    The rocks are believed to have been originally sediments, and may have been deposited as long as
                    750 million years ago, but all traces of their original sedimentary appearance have been obliterated
                    long ago. The rock is formed of layers of differing mineral composition, principally combinations of quartz and feldspar. The crystalline structure of the gneiss was produced when the rocks were buried at depths of up to 45km below the earth's surface. The layers have been bent or buckled, as if the rocks have flowed as a liquid. But this bending took place when the rocks were solid, not liquid, by a very slow process of mineral recrystallization, and under enormous pressures.

                    [Typical Slishwood Division granoblastic paragneisses showing a D3 fold (see table 2). The colour banding probably represents a composite bedding and deformational fabric]













                    The upper part of the vein, cut through mudbank limestone of the Slievemore mudbank, has been Glencarbury barytes
                    worked out. Below the unmined barytes can be seen the very top of the now-blocked adit, leading
                    into the lower, southern, part of the abandoned workings.