OR/14/025 Technical information

LAWLEY, R. 2014. User Guide: Soil Parent Material 1 km dataset. British Geological Survey Internal Report, OR/14/025.

Field descriptors

The data fields included in this dataset are as follows:

ESB DESC	CARB CNTNT	PMM GRAIN	SOIL GROUP	SOIL TEX	SOIL DEPTH	PMM1k UID	VERSION
Text description	Text description	Text description	Text description	Text description	Text description	Unique Identifier	Data descriptor

Each field comprises some form of text description or classification which follows a basic definition of its characteristics as described in the following tables:

ESB_DESC

The ESB descriptions are defined in Appendix 1. There are 155 ESB codes defined in the SPM1km dataset.

CARB_CNTNT

The carbonate content descriptions are defined as follows:

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.
Mod	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.
Low	Parent type has a low CaCO3 content due to its primary mineralogy e.g. weakly calcareous‐cemented mudstone.
Variable(low)	Parent type has a variable but typically low CaCO3 content e.g. mudstone with intermittent, weakly‐calcareous, sandstone beds.
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).

In the 1:50 000 scale dataset this field is called CaCO₃_CNTNT.

PMM_GRAIN

The Parent Material Grain size descriptions are defined as follows:

Term used	Definition	Typical Particle size (mm)
Grain size class (non‐igneous parent)
Argillaceous (Argillic)	Materials that are dominantly fine grained (clay and silt grade)	< 0.06
Arenaceous	Materials that are dominantly medium grained (fine to medium sand grade)	0.06–2.0
Rudaceous	Materials that are dominantly coarse grained (coarse sand to gravel grade)	2.0 +
Peat*	Material is Peat	NA
Grain size class (igneous parent)
Fine	Materials that are dominantly composed of fine crystals.	< 0.25
Medium	Materials that are dominantly composed of medium crystals.	0.25 > 2
Coarse	Materials that are dominantly composed of coarse crystals.	2.0 +
Not Applicable	No data applicable (typically inland water bodies).

SOIL_GROUP

The Soil Group descriptions (broad trends in soil texture as commonly used by DEFRA are defined as follows:

Term used	Definition
Heaviest soils	Soils that are generally clay‐rich.
Medium and/to Heavy soils	Soils that range from clay‐rich to loamy (generally because of heterolithic parent materials, such as interbedded mudstones and sandstones).
Medium soils	Soils that are generally loamy.
Medium and/to Lightest soils	Soils that range from loamy to silt‐rich or sand‐rich (generally because of heterolithic parent materials, such as interbedded sandstones and siltstones).
Lightest Soils	Soils that are generally sand‐rich or silt‐rich.
Mixed or Organic soils	Soils that exhibit highly variable soil textures or the presence of Peat (generally due to the heterolithic nature of the parent material or is mode of origin).
NOT APPLICABLE	No data applicable (typically inland water bodies).

SOIL_TEX

The Soil textures in the PMM1km dataset are concatenated texture codes that cover the basic Soil texture descriptions are defined as follows:

	Definition
Clay	Soil is generally dominated by clay grade particles (< 0.002 mm dia)
Silt	Soil is generally dominated by silt grade particles (0.002 mm < 0.06 mm dia)
Sand	Soil is generally dominated by sand grade particles ( 0.06 mm <2.0 mm dia)
Loam	Loam soils are soils with a distributed/even mix of particle sizes
Peat	Not a texture term, but defines areas dominated by Peat materials
Moderators
Clayey‐	This terms indicates that the dominant/ typical texture is moderated by a component of clay particles
Silty‐	This terms indicates that the dominant/ typical texture is moderated by a component of clay particles
Sandy‐	This terms indicates that the dominant/ typical texture is moderated by a component of clay particles
Peaty‐	This terms indicates that the dominant/ typical texture includes a component of Peat
Chalky‐	This terms indicates that the dominant/ typical texture includes a component of Chalk (as sand grade or gravel‐grade fragments)

SOIL_DEPTH

The Soil depth descriptions (broad trends in soil thickness) are defined as follows:

Term used	Definition
Deep	A thick soil profile is likely. Soil (and any underlying parent Material) should be easily dug to a depth of more than 1 m.
Deep‐ intermediate	The soil profile may vary from thick to intermediate. Soil (and any underlying Parent Material) can be dug to a depth of 1 m and possibly more in some places.
Intermediate	A ‘typical’ soil profile is likely. Soil (and any underlying Parent Material) can be dug to a depth of 1 m
Intermediate‐ shallow	The soil profile may vary from thin to intermediate. The underlying Parent Material is potentially difficult to dig at depths greater than 0.5 m
Shallow	A thin soil profile is likely. Digging the Parent Material beneath the soil will be extremely difficult at a depth of 0.5 m (or possibly less)
Not applicable	No data applicable (typically inland water bodies)

PMM1k_UID

This field uniquely identifies each object in the map. It is used for auditing and identification purposes.

VERSION

This field identifies the dataset (it is set to DPPMM_1 km_V1).

Map scale

The Soil Parent Material 1 km dataset is produced for use as a 1 kilometre resolution vector grid (1000 m by 1000 m ground resolution).

The data are released in ESRI shapefile formats. Other formats such as MapInfo TAB are available on request. The standard data supplied to customers has polygons in a single layer or theme, with 6 attribute fields.

Coverage

Data is provided to indicate the Parent materials and soils across Great Britain (excluding Isle of Man).

Data history

This is the first version of the Soil Parent Material 1 km dataset. BGS is continually surveying and resurveying, extending, improving and updating the underlying geological maps and databases.

Version 1 (released 2014): Derived from BGS Parent Material Map version 6. More details on this product can be found at this website http://www.bgs.ac.uk/products/onshore/soilPMM.html

Limitations

The PMM 1km datasets has been developed at cell resolution of 1 km x 1 km and must not be used at finer resolution. All spatial searches against the data should consider the limitations of spatial comparison at this kilometre scale.

Local conditions may vary and this dataset should not replace detailed site investigations. Further detail of the geology or parent material may be available on more detailed 1:10 000 scale or 1:50 000 scale geological maps.

The spatial distribution of the data is limited by the spatial accuracy and resolution of the digital geological map data (DiGMapGB-50 V6. Spatial mismatches of parent material related to mismatches in lithology type (i.e. variation in LEX_RCS across map-sheet boundaries) are unavoidable, and require resolution by reference to higher resolution map information. Further detail of the geology or parent material may be available on more detailed 1:10 000 scale or 1:50 000 scale geological maps.

The PMM 1 km data are created as vector polygons and are available in a range of GIS formats, including ArcGIS (.shp), ArcInfo Coverages and MapInfo (.tab). More specialised formats may be available but may incur additional processing costs.

The PMM 1 km dataset is concerned with the properties and potential use of NATURAL geological deposits and conditions only. It does NOT cover any man-made constructions or materials.

The PMM 1 km is based on, and limited to, an interpretation of the records in the possession of The British Geological Survey at the time the dataset was created.

An indication of the typical characteristics of a rock or soil does not necessarily mean that the properties are consistent throughout the outcrop. Such an assessment can only be made by inspection of the area by a qualified professional.

Licensing information

To encourage the use and re-use of this data we have made the data within Parent Materials 1 km available under the Open Government Licence, subject to the following acknowledgement which should be included in any material that reproduces or uses the BGS materials or data: 'Contains British Geological Survey materials ©NERC [year]'. The terms of use for every product under OpenGeoscience are displayed clearly at the top of every page.

Contact information

For all data and licensing enquiries please contact:

Enquiries

British Geological, Survey Environmental Science Centre, Keyworth

Nottingham NG12 5GG

Direct tel: +44(0)115 936 3143

Fax: +44(0)115 9363150

Email:enquiries@bgs.ac.uk