Geology of North Donegal Sheet 1

  1:100,000 series index
Area covered by the Map and Booklet

Area covered by Map



Booklet Contents

  • INTRODUCTION TO THE GEOLOGY OF NORTH DONEGAL
    • Landscape and geology
    • Some geological processes
    • A brief geological history of North Donegal
                • THE BEDROCK GEOLOGY OF NORTH DONEGAL
                  • Palaeoproterozoic - The Rhinns Complex
                  • Neoproterozoic - Dalradian Supergroup
                  • Late Silurian and early Devonian magmatism (the Donegal Batholith) and D4 to D9 deformation.
                  • Minor igneous intrusions
                  • Terranes
                  • Palaeozoic sedimentary rocks
                                  • NATURAL RESOURCES
                                    • Metallic mineral deposits
                                    • Industrial minerals and rocks
                                    • Hydrogeology
                                                    • REFERENCES AND ADDITIONAL READING LIST
                                                    • APPENDIX: Brief lithological descriptions of map units.


                                                        • Two plates from the booklet:3 lithologies

                                                          Some of the major bedrock subdivisions of North Donegal preserved in a single outcrop.
                                                          Quartzite rafts of the Ards Quartzite Formation enclosed by the Thorr Granite, somewhat
                                                          weathered. The granite is intruded by a Tertiary dolerite dyke.

                                                          The lens cap from the photographers's camera, lower centre, is 55mm in diameter.

                                                          Photograph by C. Barry Long.















                                                          Thorr Granite
                                                          Close-up view of a polished face of the Thorr Granite showing pink microcline 
                                                          feldspar, white plagioclase feldspar, glassy quartz and dark-coloured biotite and hornblende.
                                                          The rock lacks a conspicuous foliation.

                                                          Diameter of coin is 27mm.

                                                          Photograph by C. Barry Long.