Purbeck Marble
Encyclopedia
Purbeck Marble is a fossil
iferous limestone
quarried
in the Isle of Purbeck
, a peninsula
in south-east Dorset
, England.
It is one of many kinds of Purbeck Limestone, deposited in the late Jurassic
or early Cretaceous
periods.
Purbeck Marble is not a metamorphic rock
like a true marble
, but like true marble it can take a fine polish.
Its characteristic appearance comes from densely-packed shells of the freshwater snail Viviparus
. A similar material is Sussex Marble
.
In seams of the stone, which lie between layers of softer marine clays and mudstone, laid down in repeated marine ingressions, mineral impurities give some Purbeck Marble fine red and green varieties.
During the Romano-British
period, Purbeck Marble was used for inscriptions, architectural mouldings
and veneers
, mortars and pestles
, and other articles.
Purbeck Marble was also quarried in medieval times and can be seen in virtually all the cathedrals of the south of England, in columns and slab panels and flooring.
It has been less used in modern times, but a remarkable example is the church at Kingston, Purbeck, Dorset
built in 1874–1880.
Though other strata
of Purbeck Limestone are being quarried at the present time (2008), there are no active quarries in the Purbeck Marble.
However Purbeck Marble is required from time to time for restoration work, and some was extracted in 1993.
Purbeck Marble is used by a number of contemporary sculptors.
Purbeck stone has been used for restoration and new projects in ecclesiastical buildings throughout England, but especially in the south. For example it is used in the Exeter, Ely, Norwich, Chichester, Salisbury, Lincoln, Llandaff and Southwark Cathedrals and in Westminster Abbey.
The pterosaur ichnogenus Pteraichnus
is found in the Purbeck Limestone.
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
iferous limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
quarried
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...
in the Isle of Purbeck
Isle of Purbeck
The Isle of Purbeck, not a true island but a peninsula, is in the county of Dorset, England. It is bordered by the English Channel to the south and east, where steep cliffs fall to the sea; and by the marshy lands of the River Frome and Poole Harbour to the north. Its western boundary is less well...
, a peninsula
Peninsula
A peninsula is a piece of land that is bordered by water on three sides but connected to mainland. In many Germanic and Celtic languages and also in Baltic, Slavic and Hungarian, peninsulas are called "half-islands"....
in south-east Dorset
Dorset
Dorset , is a county in South West England on the English Channel coast. The county town is Dorchester which is situated in the south. The Hampshire towns of Bournemouth and Christchurch joined the county with the reorganisation of local government in 1974...
, England.
It is one of many kinds of Purbeck Limestone, deposited in the late Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
or early Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
periods.
Purbeck Marble is not a metamorphic rock
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
like a true marble
Marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...
, but like true marble it can take a fine polish.
Its characteristic appearance comes from densely-packed shells of the freshwater snail Viviparus
Viviparus
Viviparus, common name river snails, is a genus of large, freshwater snails with an operculum, aquatic gastropod mollusks. They are primitive members of the superorder Caenogastropoda.-Distribution:This genus is palaearctic in distribution....
. A similar material is Sussex Marble
Sussex Marble
West Sussex has a good concentration of relatively thin layers of Sussex Marble within the Weald Clay, a freshwater limestone referred to as "marble" as it takes a polish. It is not a geologically described one as it has not been subject to metamorphosis...
.
In seams of the stone, which lie between layers of softer marine clays and mudstone, laid down in repeated marine ingressions, mineral impurities give some Purbeck Marble fine red and green varieties.
During the Romano-British
Romano-British
Romano-British culture describes the culture that arose in Britain under the Roman Empire following the Roman conquest of AD 43 and the creation of the province of Britannia. It arose as a fusion of the imported Roman culture with that of the indigenous Britons, a people of Celtic language and...
period, Purbeck Marble was used for inscriptions, architectural mouldings
Molding (decorative)
Molding or moulding is a strip of material with various profiles used to cover transitions between surfaces or for decoration. It is traditionally made from solid milled wood or plaster but may be made from plastic or reformed wood...
and veneers
Masonry Veneer
Masonry veneer walls consist of a single non-structural external layer of masonry work, typically brick, backed by an air space. The innermost element is usually structural, and may consist of wood or metal framing or masonry...
, mortars and pestles
Mortar and pestle
A mortar and pestle is a tool used to crush, grind, and mix solid substances . The pestle is a heavy bat-shaped object, the end of which is used for crushing and grinding. The mortar is a bowl, typically made of hard wood, ceramic or stone...
, and other articles.
Purbeck Marble was also quarried in medieval times and can be seen in virtually all the cathedrals of the south of England, in columns and slab panels and flooring.
It has been less used in modern times, but a remarkable example is the church at Kingston, Purbeck, Dorset
Kingston, Purbeck, Dorset
Kingston is a small village on the Isle of Purbeck in the county of Dorset in southern England.-Location:Kingston is situated about two miles south of Corfe Castle and five miles west of Swanage. The village of Kingston is situated on a hill near Swyre Head, the highest point of the Purbeck Hills...
built in 1874–1880.
Though other strata
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
of Purbeck Limestone are being quarried at the present time (2008), there are no active quarries in the Purbeck Marble.
However Purbeck Marble is required from time to time for restoration work, and some was extracted in 1993.
Purbeck Marble is used by a number of contemporary sculptors.
Purbeck stone has been used for restoration and new projects in ecclesiastical buildings throughout England, but especially in the south. For example it is used in the Exeter, Ely, Norwich, Chichester, Salisbury, Lincoln, Llandaff and Southwark Cathedrals and in Westminster Abbey.
The pterosaur ichnogenus Pteraichnus
Pteraichnus
Pteraichnus is an ichnogenus that has been attributed to pterosaurs. It has been found in, among other units, the Lower Jurassic Aztec Sandstone....
is found in the Purbeck Limestone.