The Maplewell Group is an

Ediacaran The Ediacaran ( ) is a geological period of the Neoproterozoic geologic era, Era that spans 96 million years from the end of the Cryogenian Period at 635 Million years ago, Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last ...

lithostratigraphic 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 igneous ...

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...

(a sequence 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 ...

) present in

Leicestershire Leicestershire ( ) is a Ceremonial counties of England, ceremonial county in the East Midlands of England. It is bordered by Derbyshire, Nottinghamshire and Lincolnshire to the north, Rutland to the east, Northamptonshire to the south-east, Warw ...

in the

English Midlands The Midlands is the central region of England, to the south of Northern England, to the north of southern England, to the east of Wales, and to the west of the North Sea. The Midlands comprises the ceremonial counties of Derbyshire, Herefordshi ...

. The

strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

are exposed in

Charnwood Forest Charnwood Forest is a hilly tract in north-western Leicestershire, England, bounded by Leicester, Loughborough and Coalville. The area is undulating, rocky and picturesque, with barren areas. It also has some extensive tracts of woodland, ...

, west of

Leicester Leicester ( ) is a city status in the United Kingdom, city, Unitary authorities of England, unitary authority area, and the county town of Leicestershire in the East Midlands of England. It is the largest city in the East Midlands with a popula ...

. Besides a variety of

volcaniclastic Volcaniclastics are geologic materials composed of broken fragments (clasts) of volcanic rock. These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it ...

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

s and

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

s, there are various

breccia Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language ...

s and

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...

s. The tuffs which were laid down in water are fossiliferous; ''

Charnia ''Charnia'' is an extinct genus of frond-like lifeforms belonging to the Ediacaran biota with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture (thus exhibiting glide reflection, or opposite is ...

'', ''

Charniodiscus ''Charniodiscus'' is an Ediacaran fossil that in life was probably a stationary filter feeder that lived anchored to a sandy sea bed. The organism had a holdfast, stalk and frond. The holdfast was bulbous shaped, and the stalk was flexible. The ...

'' and '' Cyclomedusa'', are all recorded from these rocks. With the discovery of '' Teichichnus'' in the overlying Swithland Formation of the Brand Group, alongside several other ichnogenera, researchers were able to confidentially date the Brand Group to the Lower Cambrian, which has led to the research and discovery of a major hiatus and

diorite Diorite ( ) is an intrusive rock, intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is Intermediate composition, inter ...

intrusion between this group and the Brand Group. Using Zircon U-Pb dating, a date is returned of , suggesting the intrusion is Lower Edicaran in age. This also caused the Brand Group to be taken out of the Charnian Surpergroup, making the Maplewell Group the youngest group within said supergroup.

Dating

Zircon has also been found within two tuff samples collected from within in the Beacon Hill Formation. The dates recovered for both of these samples were and , which showed the Beacon Hill Formation temporally correlates with the Trepassey Formation in

Newfoundland and Labrador Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the populatio ...

. Another, more recent study collected more samples from the entire Charnian Supergroup, including samples from the Maplewell Group, which were taken from the oldest and youngest known parts of the group. The dates recovered from these samples were and respectively, refining the dates of the base and top of the group, which further showed that not only does the Maplewell Group correlate with the Trepassey Formation, but the upper layers are now known to overlap it.

References

{{Reflist Ediacaran geology Geology of Leicestershire Geological groups of the United Kingdom Sandstone groups Mudstone groups Siltstone groups Tuff groups Dacite groups Andesite groups