Hydrostratigraphic Rock Unit Groups 1:100,000 Ireland (ROI) ITM

Category: Science
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There are more than 1,200 geological formations and members (rock units) in the 1:100,000 Bedrock Geology map. Rock properties such as colour, grain size and type, origin, fossil and mineral content are used to define formations and members. A lot of these properties are not relevant for groundwater flow through the rocks (for example, type of fossil).

To produce this dataset, all of the formations and members were assessed and assigned to one of 27 'Rock Unit Groups' that are significant for the way that groundwater might flow through those rocks. The Rock Unit Groups also take into account geological age.

This map is to the scale 1:100,000. This means it should be viewed at that scale. When printed at that scale 1cm on the map relates to a distance of 1km.

It is a vector dataset. Vector data portray the world using points, lines, and polygons (areas).

The data is shown as polygons. Each polygon holds information on the rock unit group name, code and a unique id.

Data Resources (4)

SHP
ESRI Shapefile
ESRI REST
ESRI REST
DATA VIEWER
Data Viewer

Data Resource Preview - WMS

Theme Science
Date released 2006-01-23
Date updated 2021-10-22
Dataset conforms to these standards The INSPIRE Directive or INSPIRE lays down a general framework for a Spatial Data Infrastructure (SDI) for the purposes of European Community environmental policies and policies or activities which may have an impact on the environment.
Rights notes ['Creative Commons Attribution 4.0 International (CC BY 4.0)', 'Data that is produced directly by the Geological Survey Ireland (GSI) is free for use under the conditions of Creative Commons Attribution 4.0 International license.\n\nhttps://creativecommons.org/licenses/by/4.0/\n\nhttps://creativecommons.org/licenses/by/4.0/legalcode\n\nUnder the CC-BY Licence, users must acknowledge the source of the Information in their product or application.\n\nPlease use this specific attribution statement: "Contains Irish Public Sector Data (Geological Survey Ireland) licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence".\n\nIn cases where it is not practical to use the statement users may include a URI or hyperlink to a resource that contains the required attribution statement.', 'license']
Update frequency Never
Language English
Landing page https://gsi.geodata.gov.ie/portal/apps/webappviewer/index.html?id=d333a8a9b6ab44378411fc0d973db4ef
Geographic coverage in GeoJSON format {"type":"Polygon","coordinates":[[[-11.0, 50.0],[-11.0, 56.0], [-5.0, 56.0], [-5.0, 50.0], [-11.0, 50.0]]]}
Spatial Reference Systems (SRS) Irish Transverse Mercator (ITM, EPSG:2157)
Vertical Extent {"verticalDomainName": "sea level", "minVerticalExtent": "0", "maxVerticalExtent": "-500"}
Provenance information There are more than 1,200 geological formations and members in the 1:100,000 Bedrock map. Rock properties such as colour, grain size and type, origin, fossil and mineral content are used to define formations and members. A lot of these properties are not relevant for groundwater flow through the rocks (for example, type of fossil). To produce this dataset, hydrogeologists (specialist geologists interested in groundwater) assessed all of the formations and members in the 1:100,000 Bedrock map. Each one was assigned to one of 27 'Rock Unit Groups'. This was done using information such as geological age, the make-up of the rock (‘lithology’), whether the rock is layered or not. To help the hydrogeologists decide what rock properties are important for groundwater flow, earlier studies were consulted. Most of these studies were the Groundwater Protection Schemes for different counties in Ireland that had been done by the GSI. The studies related the groundwater flow and storage (‘aquifer’) properties to the bedrock properties using information from wells, springs, river flows and other sources. Examples of important rock properties for groundwater flow are: limestone purity and how easily it will dissolve in rainwater to create cavities (become ‘karstified’); whether layering (‘bedding’) is present or absent, and does it help the rock to fracture (‘jointing’); how much the rocks have been deformed by earth movements, and what effect that has had on creating or destroying openings that groundwater can flow through. (For example, older rocks have been deformed many times since their formation, so lack pore spaces and connected fracture networks). Phase 1 1:100,000 RUG map (2004) IG The bedrock shapefile was used (1:100,000 bedrock map (2003) IG). A list of all formations and members (the ‘Rock Units’) was created from the ArcGIS shapefile and exported to MS Excel. An initial set of Rock Unit Groups was established for obvious groupings. An example of this would be the Devonian Old Red Sandstones. All of the formations and members were assigned to one of the initial Rock Unit Groups based on age, understanding gained from the Groundwater Protection Schemes, and properties important for groundwater flow such as bedding. The short bedrock description in the 1:100,000 bedrock map, and the documents accompanying the paper 1:100,000 map sheets were used to find out about the rock properties. Through a process of iteration, 27 Rock Unit Group categories were established for the rocks found in the Republic of Ireland. These are as follows (listed by youngest to oldest) 1. Permo-Triassic Sandstones 2. Permo-Triassic Mudstones and Gypsum 3. Westphalian Sandstones 4. Westphalian Shales 5. Namurian Shales 6. Namurian Sandstones 7. Namurian Undifferentiated 8. Dinantian Shales and Limestones 9. Dinantian Mixed Sandstones, Shales and Limestones 10. Dinantian Sandstones 11. Dinantian Pure Bedded Limestones 12. Basalts & other Volcanic rocks 13. Dinantian Upper Impure Limestones 14. Dinantian Dolomitised Limestones 15. Dinantian Pure Unbedded Limestones 16. Dinantian Lower Impure Limestones 17. Dinantian (early) Sandstones, Shales and Limestones 18. Dinantian Mudstones and Sandstones (Cork Group) 19. Devonian Kiltorcan-type Sandstones 20. Devonian Old Red Sandstones 21. Granites & other Igneous Intrusive rocks 22. Silurian Metasediments and Volcanics 23. Ordovician Metasediments 24. Ordovician Volcanics 25. Cambrian Metasediments 26. Precambrian Quartzites, Gneisses & Schists 27. Precambrian Marbles Phase 2 (2008) Small mis-classifications were corrected and the map was converted to ITM within ArcGIS. The dataset comprises 1 shapefile. 1) Rock_Unit_Group_ITM_20xx.shp – A polygon shapefile that contains geological information on the Rock Unit Group Code and its description. Credits Úna Leader, Project Hydrogeologist, 2002-2004 Gerry Baker, Project Hydrogeologist, 2002-2004 Natalya Hunter Williams, Project Hydrogeologist, 2002, 2004. Senior Hydrogeologist, Groundwater Section, 2000-present Eugene Daly Geoff Wright Donal Daly Vincent Fitzsimons Groundwater Section Staff for County Groundwater Protection Schemes, Geological Survey Ireland, 1990-2008
Period of time covered (begin) 2009-12-17
Period of time covered (end) 2012-01-10