Geology discussion is fine!

Quoted text begins.My knowlegdes about rocks are in the field of the Geology: their origin,
composition, stucture and such things.
Do you think I should stay in touch with you all?
End of quote.

Hello Daniel,

Yes - you should keep on contriuting to the
Learningstone discussion group, as it's intended for
people with varied interests in stone. Geology and
geomorphology are essential in understanding how
different stones on our Earth have been formed and
weathered - Gological and geomorphologial processes
influence the carving, working and weathering
characteristics of stone - important when considering
how a particular type of stone should be used in
architecture and/or sculpture. Portland stone has to be
used in the correct bedding plane, for example, in
buildings - if the natural geological bedding plane is
ignored, then the stone will weather in a different way.
The denser beds of Portland stone (Basebed and Whitbed)
were traditionally used in the lower areas of buildings
- reflecting there geological position lower down
(deeper down) in the Earth.

Again, it's the geological structure of Portland stone,
comprising calcium carbonate in the form of oolites
(tiny spheres), that allows the stone to be carved in
any direction, with very fine detail. This stucture
also affects the weathering properties of the stone - so
in an environment such as London - even with high levels
of air pollution, the stones surface will weather back
very slowly. I've also heard it said that Portland
stone has a surface that is self cleaning in acid rain
environments.

Have you tried the Links Page in the Learningstone
Website? I know that there is a very detailed site on
the Geology of Portland within the Links. Have a look
and let me know what you think?

Paul Crabtree.
Portland Sculpture and Quarry Trust.

-------------------------------------
Portland Sculpture and Quarry Trust
* Address
31 Easton Square
Portland
Dorset
DT5 1BU
UK
* Phone/Fax
01305 826 736