The Coal Measures Group is a
lithostratigraphical
Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology.
In general, strata are primarily igneo ...
term coined to refer to the
coal
Coal is a combustible black or brownish-black sedimentary rock, formed as stratum, rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen ...
-bearing succession of rock
strata
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...
which occur in the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
within the
Westphalian Stage
Stage or stages may refer to:
Acting
* Stage (theatre), a space for the performance of theatrical productions
* Theatre, a branch of the performing arts, often referred to as "the stage"
* ''The Stage'', a weekly British theatre newspaper
* Sta ...
of the
Carboniferous Period. Other than in
Northern Ireland
Northern Ireland ( ga, Tuaisceart Éireann ; sco, label=Ulster-Scots, Norlin Airlann) is a part of the United Kingdom, situated in the north-east of the island of Ireland, that is variously described as a country, province or region. North ...
the term is now obsolete in formal use and is replaced by the
Pennine Coal Measures Group
The Pennine Coal Measures Group is a lithostratigraphical term referring to the coal-bearing succession of rock strata which occur in the United Kingdom within the Westphalian Stage of the Carboniferous Period. In formal use, the term replac ...
,
Scottish Coal Measures Group
The Scottish Coal Measures Group is a lithostratigraphic unit referring to the coal-bearing succession of rock strata which occur in Scotland during the Westphalian regional stage of the Carboniferous Period. It is the Scottish portion of th ...
and the
South Wales Coal Measures Group
The South Wales Coal Measures Group is a lithostratigraphical term referring to the coal-bearing succession of rock strata which occur in South Wales within the Westphalian Stage of the Carboniferous Period. The Group name is also applied to roc ...
for the three distinct depositional provinces of the
British mainland.
Pennine Coal Measures Group
Within the
Pennine Basin the Pennine Coal Measures Group is preceded (underlain) by the
Millstone Grit Group which is of
Namurian
The Namurian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 326 and 313 Ma (million years ago). It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Namurian ...
age. It is succeeded (overlain) by the
Warwickshire Group
The Warwickshire Group is a lithostratigraphic unit of rock strata defined within the British Carboniferous system. Within the Pennine Basin it overlies (i.e. postdates) the Coal Measures Group and is deemed to be of late Westphalian and Step ...
which comprises a largely non-productive sequence of
red bed
Red beds (or redbeds) are sedimentary rocks, typically consisting of sandstone, siltstone, and shale, that are predominantly red in color due to the presence of ferric oxides. Frequently, these red-colored sedimentary strata locally contain th ...
s. It comprises the:
:* Pennine Upper Coal Measures Formation
:* Pennine Middle Coal Measures Formation
:* Pennine Lower Coal Measures Formation
The 'Pennine Basin' includes all of the
coalfield
A coalfield is an area of certain uniform characteristics where coal is mined. The criteria for determining the approximate boundary of a coalfield are geographical and cultural, in addition to geological. A coalfield often groups the seams of ...
s of northern England and the
English Midlands
The Midlands (also referred to as Central England) are a part of England that broadly correspond to the Kingdom of Mercia of the Early Middle Ages, bordered by Wales, Northern England and Southern England. The Midlands were important in the In ...
together with the
Canonbie Coalfield of southern Scotland and the coalfields of
northeast Wales and
Anglesey
Anglesey (; cy, (Ynys) Môn ) is an island off the north-west coast of Wales. It forms a Local government in Wales, principal area known as the Isle of Anglesey, that includes Holy Island, Anglesey, Holy Island across the narrow Cymyran Strai ...
.
Scottish Coal Measures Group
A similar scheme operates in the Midland Valley Basin of
Scotland
Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to th ...
.
South Wales Coal Measures Group
In those coalfields to the south of the former
Wales-Brabant High i.e. the
South Wales
South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards ...
,
Bristol
Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city i ...
,
Somerset
( en, All The People of Somerset)
, locator_map =
, coordinates =
, region = South West England
, established_date = Ancient
, established_by =
, preceded_by =
, origin =
, lord_lieutenant_office =Lord Lieutenant of Somerset
, lor ...
,
Forest of Dean
The Forest of Dean is a geographical, historical and cultural region in the western part of the county of Gloucestershire, England. It forms a roughly triangular plateau bounded by the River Wye to the west and northwest, Herefordshire to t ...
and concealed
Oxfordshire and
Kent
Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...
coalfields, the corresponding group is the South Wales Coal Measures Group. It comprises the:
:* South Wales Upper Coal Measures Formation
:* South Wales Middle Coal Measures Formation
:* South Wales Lower Coal Measures Formation
In South Wales, the larger part of what had been the Upper Coal Measures now forms the Pennant Sandstone Formation in the overlying Warwickshire Group.
[British Geological Survey 1:625,000 scale geological map ''Bedrock geology: UK South'' (5th edn) BGS, Keyworth, Notts] The South Wales Coal Measures Group is preceded (underlain) by the
Marros Group
The Marros Group is the name given to a suite of rocks of Namurian age laid down during the Carboniferous Period in South Wales. These rocks were formerly known as the Millstone Grit Series but are now distinguished from the similar but geogra ...
.
References
Carboniferous United Kingdom
Coal in the United Kingdom
Geological groups of the United Kingdom
Geologic formations of the United Kingdom
Carboniferous England
Carboniferous Scotland
Carboniferous Wales
Carboniferous System of Europe
Stratigraphy of the United Kingdom
{{UK-geologic-formation-stub