Building Stones – why should we be interested in Urban Geology?

Urban Geology is the geology of the built environment. This includes the building stones and other materials used in town and cities as well as the tantalising glimpses of the pre-urban landscape and underlying bedrock. Cities are shunned by many geologists and considered as somewhere to escape, and yet many geologists live and work in cities, whether in universities or in the stone, mineral and hydrocarbon extraction industries, and there is much to learn from building stones. Importantly they are an untapped and enormous resource for teaching at all levels. Take the time to stroll down the average shopping street or through the City of London on a sunny Sunday morning and one can find one’s self on a global tour of the Earth’s geology from Precambrian migmatites to Quaternary travertines, from the Jurassic seas of Dorset to the Permian of the Oslo Graben or the Bushveld Complex of South Africa. Here are just a few of London’s examples …

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Above left, Chandos House on Queen Anne Street is one of the few buildings in London built from Edinburgh’s Craigleith Stone. Above right, a new coffee shop on Mortimer Street has a bar of Madagascan anorthosite.

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Above left, 1, Poultry is built from a Jurassic sandstone from Helidon, Australia, with stripes of Wilderness Red from the Forest of Dean. On the right, London Metropolitan University’s buildings on Moorgate have columns on Cornish Granite.

The urban landscape is also a great place to learn many aspects of geology, especially from building stones. Whilst there is no substitute for exploring rocks in situ to obtain an understanding of the three-dimensional geometries of outcrops, much can be learned about petrography, petrology, palaeontology and the environment of formation of many rocks on the average high street. The urban geologist is exposed to an enormous variety of rock types, far more than the committed field geologist could ever see in outcrop in the field.

Find out more about the Urban Geology of London from a series of self guided walks. They  are free to download here http://www.ucl.ac.uk/~ucfbrxs/Homepage/UrbanGeology.htm

The latest walk features Irongate House, an uninspiring 1970s office block that is clad with truly inspiring rocks, a granite-gneiss from near Vredefort in South Africa. This region was hit by a huge meteorite impact 2 billion years ago and the black, glassy melts associated with the impact can be seen cross cutting the polished slabs.

IMG_0033 Left, ‘pseudotachylites’ impact melt glasses form black veins cross-cutting Parys Gneiss from near Vredefort in South Africa on Irongate House on Houndsditch in the City of London.

#UrbanGeology

©Ruth Siddall 2015

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About Ruth Siddall

Geologist, geoarchaeologist and co-author of The Pigment Compendium. Follow @R_Siddall; Facebook|Cultural & Urban Geology
This entry was posted in Building, Geology, London, Stone, Urban Geology and tagged , , , , , . Bookmark the permalink.

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