Purbeck Marble

As Purbeck marble (English Purbeck Marble ) a stone is referred to, which was won mainly on the Isle of Purbeck, a peninsula in the county of Dorset on the south coast of England.

In rock known union sense, it is a fossiliferous limestone. As this limestone can be polished well and his name is historically come, has for this sedimentary rocks get additional " marble ", even though it has not been altered metamorphic. Purbeck marble has great cultural and historical significance in England and was often used for churches in southern England.

Occurrence

Purbeck marble was built in the late Jurassic and early Cretaceous. The deposits formed in the exchange of salt and fresh water in bays and freshwater zones ( lakustrisch ) before about 146-141 million years ago ( former Purbeck stage). The geological structure of the Isle of Purbeck is highly differentiated.

The building stone obtained from the upper layers of the stone crushers and stone masons as Purbeck Freestone ( Laugton quarries ) and referred from the lower layers as Purbeck - Portland Stone. From the Seacombe quarries near Swanage Purbeck came the Cliff Stone. Of these, the alternative name Purbeck Stone is derived. The acquired building stone of the uppermost layers of assessment ( Upper ostracod Clays and Shales Member) of the former Purbeck Formation were sometimes referred to their special decorations separately as Purbeck Marble. They embark on zones with shale.

The sedimentation in the eastern Dorset began at the time of the Upper Jurassic ( Tithonian ). Initially, clay was deposited on the bottom of the bays. This was followed by so-called Portland sand and limestone layers of the Portland - level ( currently part of the Tithonian ) and the Purbeck stage ( currently part of the Berriasian ). In the layers of the former Purbeck stage fossilized remains of shellfish, fish and reptiles are included. Fossil deposits in the Purbeck marble consist of freshwater snails such as the Viviparus ( river snails ), Valvata, Lymnaea ( pond snails ), Planorbis (plates snails) Hydobia ( Common mud snail ), Physa ( bladder worm ), Melania, Cyclas and Unio.

The characteristic appearance of the Purbeck marble originates primarily from the fossilized shells of freshwater snails Viviparus. These fossils are also included, especially the English Sussex Marble, which is also known as Petworth marble or Winklestone. The benches of limestone occurrence of Purbeck marble are supported strongly and separated by sound and Lehmlagen. This natural reservoir situation facilitates its extraction in the quarry. This rock is provided with a multicolored appearance of green, gray, blue, beige to brown.

In the deposit of Purbeck marble numerous dinosaur tracks have been found.

Use

It is believed that Purbeck marble wurde.In used already in the 1st century of the Romano-British period it was used for construction and building stone and for plates. It also consumer items of daily life such as mortar and pestle were prepared therefrom, for the production of mortar it was dismantled. Chance to have been also delivered to the Normandy from the 4th to the 11th century Purbeck marble.

It is believed that this limestone was processed in the 11th century, especially in Corfe and that the coast has promoted the success of this cut stone. Later, the production of building stone shifted to London for the construction of numerous churches and Westminster.

Purbeck marble was installed at many cathedrals in southern England in the Middle Ages, this also used for columns and floor slabs. Around the 1880s the church buildings in Kingston, Purbeck and Dorset were built from it. For restoration works in the south of England this natural stone found in numerous art historical vitally important churches use, such as in Exeter, Ely, Norwich, Chichester, Lincoln, Landaff, Southwark and Westminster Abbey. In Salisbury Cathedral are the pillars and their foundation plates and shafts of Purbeck marble. Salisbury has more Purbeck marble than any other cathedral.

Currently, the Purbeck marble is no longer actively mined, but blocks as required for restoration work occasionally obtained or used embedded Roughs. By English stone sculptors Purbeck marble is preferred because of its good formability.