Article from Issue Number 12/2 April 2005
BUILDING STONES
OF THE BRITISH LIBRARY
Led by ERIC ROBINSON
Thursday 17 February 2005
A well wrapped-up group of
us assembled on a cold afternoon outside the main entrance of the British
Library for our talk about the building stones led by Eric Robinson. We started
by marching across to the main gate so that we could get an overview of the
building as a whole. Rising above the roof, on our right, we could see the
elaborate architecture of St Pancras Station, and Eric explained some of the
design issues - it would not have been appropriate to match the style of the
station, but the colours of the building materials were chosen to complement it,
hence the rich red-brown of the brickwork and silver grey roof tiles.
Eric firstly drew our
attention to the white limestone slabs on top of the South Wall, just inside the
main gate. These are Hauteville Limestone from the French Jura Mountains. Lower
Cretaceous in age, they show plenty of evidence of the benthos of a warm shelf
environment. The slab nearest the gate is the most bioturbated; in others we
made out gastropods up to 15 cm long, bivalves and rudists. In all the slabs we
could see stylolites, sutures caused by the pressure of deep burial.
We then turned to look up at
the gate. Across the top are 8 large blocks of red Dumfriesshire sandstone from
the Southern Uplands. These Permo Triassic sands were wind blown, some river
sorted. We looked for bedding markings and Eric described the arrangement of the
blocks as "patch and match." At ground level, we inspected an attractive reddish
brown granite at the base of the outer wall. It has even-sized crystals of brick
red feldspar, quartz, biotite mica and hornblende, giving it an overall
homogeneous look. It is a Drammen granite from the Oslo Fiord in Norway and Eric
said it came from the Royken Quarry. This granite is also used at the front of
the Conference Centre and blends in with the redish brown scheme.
On the ground we examined
the Hauteville Limestone slabs as we walked down the slope towards the
Conference Centre. We noticed how the rain and dirt emphasised the markings on
them: no need for Eric's bottle of water today. By the Conference Centre door
Eric pointed out a slab that he said was Grade 1 listed. Was he joking? Probably
not. It was teeming with evidence of fauna from the Tethyan Sea where it
originated. We identified clusters of bivalves and rudists, gastropods and a
sponge.
In the centre of the
Courtyard is a circular, slightly sunken Quiet Area that did seem to be
sheltered from the noise of the Euston Road. It is ringed by eight limestone
pedestals, and on top of each is a large smooth stone with a crude human figure
carved around it by Antony Gormley. As usual, Eric had the inside information -
Gormley had wanted to use erratics from Scotland but they were not willing to
part with them. Malmo in Sweden had been more accommodating.
As a result the pedestals
are topped with eight Pre Cambrian, Baltic Shield erratics including dolerite,
gabbro, gneiss, basalt and granite, all showing evidence of their original
ancient craton having suffered stress before they were carried south to Malmo by
glaciers. We could make out metamorphic textures and augen 'eyes.' Di climbed up
to examine a granite at closer quarters, and confirmed the quartz crystals
showed a blue-purple colour - evidence of internal fractures in this hard
mineral.
We mused on the significance
of Gormley's work, the relationship between the figures he has carved and the
ancient stones they embrace. Eric told us of a children's playground in Holland
where erratics have been sited for children to scramble over. The stones have
numbers relating to a map showing their place of origin. He thought we could
make similar use of erratics here, and suggested Scunthorpe, where they are
uncovered as the gravels are extracted. It was too cold for musing further, so
we made haste to get into the warmth of the Library. After announcing our
presence at the Information Desk we looked first at the Portland Stone floor of
the foyer. In the creamy coloured limestone we could clearly see the small white
circular shapes of calcareous algae, known as pellets or biscuits. We saw
evidence of bivalves and shell fragments of burrowing oysters, and could make
out pathways in the sediments. The wall blocks in the foyer are made of Italian
Travertine. This is a freshwater limestone deposited by springs cascading down
the sides of volcanoes in the Tivoli Hills to the north of where Rome now
stands. Because of its non-slip qualities, due to having numerous cavities,
Travertine is frequently used as flooring. Some of us recognised it as 'MacDonaldstone.'
The elongate cavities are the spaces left where the stems of reeds and rushes
growing in the warm spring water have crumbled away during lithification. On the
wall in the Library foyer the stone is used on its side, so that these features
are horizontal. In one area the cavities have been filled to give a smooth face
to take the lettering commemorating the opening of the building by HM the Queen
on 25 June 1998. Eric referred to this as 'stocked' or 'plugged' Travertine. On
the landing above the foyer, the dark slabs of blue-grey limestone are teeming
with fresh-water bivalve shells. This is lower Cretaceous, Purbeck limestone,
most likely from the quarry at Worth Maltravers near Swanage. Eric explained
that the dark colour represents a muddy, foul-smelling, sulphurised, stagnant
environment, which obviously suited the bivalves, as their remains are abundant.
We could also see long calcite veins, formed when the rock dried and cracked
during its formation. Eric's talk finished here. It had been a fascinating and
thoroughly enjoyable two hours. For many of us it was our first visit to the new
British Library building and we will be well aware of the geological aspects of
it on further visits. I shall look forward to sitting in the Courtyard,
surrounded by those ancient erratics, in warmer weather. As usual, Eric was full
of anecdotes and stories, as well as his indepth knowledge of all the materials
used. Marilyn thanked him on our behalf.
Rosemary Almond
