| "Nordic Stone" is a 60-page report
compiled by eight authors; from the Geological Surveys of Norway,
Sweden and Finland, the Swedish Natural Stone Association and the
Swedish Road and Transport Research Institute, and two Finnish
universities. A further clue to their remit is that the joint
publishers are UNESCO and the International Association of Engineering
Geology which has its headquarters in Finland.
Their report starts by identifying eight types of natural stone from
granite to soapstone, that are found in the nordic countries, and
reviewing the history and heritage of the working of natural stone
over the past 1000 years. Stone buildings record changing periods of
prosperity and decline as each of the nordic countries (including
Denmark) took turns at being top dog. Stone architecture was
introduced with Christianity and used in the early churches, a prime
example being Trondheim Cathedral. Masons came from England, Germany
and Estonia to teach Scandinavians how to quarry and work the stone
and to build with it.
The expansion of cities, especially in Sweden, post 1550 led to many
civic buildings in stone, and the new nobility required castles and
stately homes. During the industrial revolution, hard stone was
preferred, for railway construction, etc. and improved technology made
this possible. In the 20th century modern architecture featured
concrete, and the market for stone went into decline. Since 1970,
however, natural stone has come back into favour, and production is
centred on larger-scale quarries operated by fewer, larger
enterprises. Both home consumption and exports have risen.
Stone resources and distribution are reviewed by authors from each of
the three countries. Their map shows that the eight rock types are
quarried mainly in the southern halves of each country, with some 150
natural stone deposits plotted.
The quarry near Larvik that we visited on the WEGA 2000 tour of
southern Norway is one of a cluster, reflecting the enduring
popularity of larvikite, which has been quarried for 120 years.
Currently, annual production from twenty quarries is 200,000 tons of
rough blocks. I was surprised the following year at OU Summer School,
to see metre sized blocks of larvikite being put in place to protect
the small harbour at Staithes on the N Yorks coast. These would have
been rejects after the preliminary cutting stage. The deposits are
listed, country by country and town by town, giving the commercial
name and a brief description of the geology. This would be an
invaluable reference for anyone planning a geology tour in
Scandinavia, although the authors have not included company names and
addresses. A generalised stratigraphic column shows that the Finnish
deposits are palaeo-proterozoic (2500 - 1500 Ma) which I guess is due
to Finland being nearer the centre of the Baltic Shield. Norway has a
greater age span, from Archean gneiss in Finnmark right through to
Permian rocks (larvikite at Larvik, granite at Royken and syenite at
Oslo). The Swedish quarries extract rocks covering the whole of the
Proterozoic, and there is some Palaeozoic working, the youngest being
Silurian limestone on the Baltic island of Öland.
The authors give an overview of modern geophysical techniques used in
prospecting, and new quarrying practices, such as diamond wire sawing.
Nowadays, extraction and working are highly mechanised and automated.
Environmental issues include the noise, dust and handling of leftover
stone, and safety.
Annex 1 to the report list the properties (density, water absorption,
compressive strength, flexural strength) of selected types of natural
stone, according to their commercial name and colour. Annex 2 gives
their quartz and biotite content "Stone is hard to cut with high
quartz content and more prone to wear with high biotite content."
"Nordic Stone' relates construction value to the aesthetics of our
living envirironment, and the heritage of Scandinavian stone buildings
to the evolution of quarrying technologies. It does so in a readable,
informative and well illustrated fashion, with proper regard to the
background geology.
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