• Local GAPs

Slide Show

Worcestershire Geological Succession

Geological Time

Geological time is divided into eons, eras, periods, epochs and ages, with eons representing the largest stretches of time (500 million years or more). Each eon is subdivided into eras, which in turn are divided into periods etc… This nomenclature ends with ‘ages’, which represent the smallest increments of geological time, on the order of a few hundred thousand years.

Rocks of similar age can grouped together and placed into a geological succession, where they lie in between rock units of greater and lesser age. As geology varies across distances, these geological successions are only relevant to a specific geographical area. Geologists can get some idea of what processes were taking place in Worcestershire over millions of years, by looking at what types of rocks were forming at different times in the geological succession. The most useful subdivisions of geological time are periods, epochs and ages, as rocks dated to these resolutions can give both general and detailed information on the ancient environment.

In this geological succession, periods and epochs are used to describe the older geological succession (Precambrian – Jurassic) that is seen in Worcestershire. The most recent geological period (the Quaternary) is described in terms of period and age, as the detail preserved within these young rocks and sediments allows for more detailed interpretation.

Period

Age

Stratigraphic Unit

Quaternary

Holocene

Aeolian sands

Mass Movement Deposits

Peat Deposits

Eymore Member

Devensian

Alluvial Fans and related
Deposits

Avon Valley Formation

Severn Valley Formation

Power House Member (SVT 1)

Bretford Member (AVT1)

Worcester Member (SVT2)

Wasperton Member (AVT2)

Holt Heath Member (SVT3)

Ipswichian

New Inn Member (AVT3)

Ailstone Bed (AVT4)

Kidderminster Station Member
(SVT4)

Pershore Member (AVT5)

Bushley Green Member (SVT5)

Hoxnian

Spring Hill Member (SVT6)

Anglian

Ridgacre Formation

Glaciogenic Deposits

Risbury Formation

Wolston Formation

Cromerian

Mathon Formation

TIME GAP

Period

Epoch

Stratigraphic Unit

Jurassic

Inferior Oolite

Salperton Limestone Formation

Aston Limestone Formation

Birdlip Limestone Formation

Lias Group

Whitby Mudstones Formation

Marlstone Rock Formation

Dyrham Siltstone Formation

Charmouth Mudstone Formation

Blue Lias Formation

Triassic

Penarth Group

Lilstock Formation

Westbury Formation

Mercia Mudstone Group

Blue Anchor Formation

Branscombe Mudstone Formation

Arden Sandstone Formation

Sidmouth Mudstone Formation

Tarporley Siltstone Formation

Sherwood Sandstone Group

Bromsgrove Sandstone Formation

Wildmoor Sandstone Formation

Kidderminster Formation

Permian


Bridgnorth
Sandstone Formation

Warwickshire Group

Clent Formation

Carboniferous

Westphalian

Salop Formation

Halesowen Formation

Etruria Formation

Coal Measures Group

Upper Coal Measures

Middle Coal Measures

Lower Coal Measures

Brockhill Dyke

Shatterford Dyke

Devonian

Lower Old Red Sandstone

St Maughans Formation

Silurian

Pridoli

Downton Group

Raglan Mudstone Formation

Ludlow

Downton Castle Sandstone
Formation

Upper Ludlow Shale Group

Whitcliffe Formation/Whitcliffe
Flag Member

Leintwardine Formation/ Mocktree
Shale Member

Aymestry Limestone Formation

Lower Ludlow Shale Group

Bringewood Formation

Elton Formation

Wenlock

Much Wenlock Limestone Formation

Coalbrookdale Formation

Woolhope Limestone Formation

Llandovery

May Hill Sandstone Group

Wyche Formation

Cowleigh Park Formation

Ordovician

Tremadoc

Bronsil Shale

Lickey Quartzite

Barnt Green Volcanics

Cambrian

Merioneth

White-Leaved Oak Shale Formation

Comley

Hollybush Sandstone Formation

Malvern Quartzite Formation

Precambrian

Kempsey Formation

Warren House Formation

Malverns Complex

Reproduced with the permission of the British Geological Survey © NERC. All Rights Reserved. Based upon information in the BGS Lexicon and the BGS memoir ‘Geology of the country around Worcester, 1:50,000 scale sheet 199.

Site Examples:

Period