Parent Material Carbonate Content

The map covers Great Britain and integrates geology and soil characteristics at a scale of 1:50 000 (visible at higher zoom levels), with a 1km resolution version available for regional overview.

The Parent Material Carbonate Content classification is based on expert judgment of the likely content of CaCO3 in the total rock-mass of each parent material. Note that the map uses combinations of terms that refer to: High, Moderate, Low and Variable calcium carbonate content. As a rule of thumb, these categories are based on the bulk mineralogy of the parent material. For example, High carbonate content would be expected for a chalk or limestone parent material type; Low carbonate content would be representative of weakly, calcite-cemented sandstone. The term Variable is used where the parent material comprises two or more distinct lithologies e.g. interbedded limestone and mudstone where it is not possible to clearly identify the precise parent type at any given location. Users should note that land management practices and natural weathering processes of parent materials play a significant role in controlling carbonate content (it has not been possible to factor in these influences within the scope of this dataset) and so the classes shown in this dataset should be regarded as wholly 'indicative'.

These data are made available under the Open Government Licence, subject to the following acknowledgement accompanying the reproduced BGS materials: "Contains British Geological Survey materials © NERC [year]".

CaCO<sub>3</sub> map legend

Map legend

Key Term used Definition
HIGH Parent type has a high CaCO3 content due to its primary mineralogy e.g. Chalk.
VARIABLE (HIGH) Parent type has a variable but possibly high CaCO3 content due to lithological variation e.g. Interbedded limestone and calcareous mudstone beds.
MODERATE Parent type has a moderate CaCO3 content due to its primary mineralogy e.g. dolomite.
VARIABLE Parent type has a variable (high to low) CaCO3 content due to heterolithic distribution of carbonate e.g. Till with chalk-gravel.
VARIABLE(LOW) Parent type has a variable but typically low CaCO3 content e.g. mudstone with intermittent, weakly-calcareous, sandstone beds.
LOW Parent type has a low CaCO3 content due to its primary mineralogy e.g. weakly calcareous-cemented mudstone.
NONE Parent type has a no primary CaCO3 content.
UNKNOWN Parent materials whose precise lithology is unclear (generally highly variable at short scales) or from a location that no mineralogical/geochemical data is available to confirm primary mineralogical content.
NOT APPLICABLE No data applicable (typically inland water bodies).
Title Parent Material Grain Size
Source British Geological Survey
Enquiries BGS Enquiries
Scale(s) 1:50 000 and 1km grid resolution
Coverage Great Britain
Format GIS polygon data. (ESRI, MapInfo, others available by request)
Price 30p per km2 for commercial use of 1:50 000 scale data. Subject to licence fee and data preparation fee. More information about licensing data.
The 1 km grid data is free for use under Open Government Licence terms.
Uses Local to national level use
Downloads Free 1km grid data and sample 1:50 000 scale data
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WMS link https://map.bgs.ac.uk/arcgis/services/
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