 |
| The Roman Theatre in Cartagena |
In Cartagena, a place that I will always remember as the 'city of walls', the old Roman theatre is probably its best known tourist attraction; however, it is quite likely that most of the people who disembark from the many cruise ships, which circumnavigate the Mediterranean Sea, never walk beyond this astonishing place, except to do some shopping.
 |
| La Colina de Despeñaperros |
Arriving
on the bus from Murcia, where I had spent a week participating in an intensive cultural
and language exchange programme, I was confronted by the Muralla de Carlos III, behind which rises La Colina de Despeñaperros - itself defended by another fortification.
This
is just one of the five fortified hills that form the core of the old city and, outside the city wall, two other hills have also been well developed for
their strategic importance.
Having left my directions to the tourist information office in the house of my Spanish hostess, I headed off in the general direction of the port along the main street and, wandering off along many of the side streets, I saw a few of these hills poking out from behind the buildings and many fragments of ancient walls. Perhaps it was the effects of "La Gripe" or, unusually for me, the lack of a map, but it took nearly an hour before I found El Teatro Romano, which was the main reason for my visit to Cartagena.
Finally
finding a place to buy a map, I soon discovered the whereabouts of El Teatro
Romano and, whilst trying to find the entrance, I explored the
steep sided hill, into which the theatre has been built.
Stopping to take my
bearings, I encountered a magnificent view of the mountains that flank the harbour. These
are part of the Alpujárride Complex, where the rocks were deformed
into a stack of thrust nappes during the Alpine Orogeny.
In the perimeter walls that overlook the theatre, I was struck by the variety of colours and textures than can be seen in the igneous, sedimentary and metamorphic rocks - sandstones, limestones,
dolomites, dolerites, quartzites, phyllites and schists are all found there.
 |
| Views from El Auditorio Parque Torres |
With the surrounding hills to take a good look
at, the local geology can easily be explained from the
vantage point here. There is also a good opportunity to look at the various stonemasonry techniques
that have been used to build these walls, with various degrees of tooling and the
reinforcement of the rubble walling using courses of bricks – a style favoured by the Romans.
None of the rocks seen in the basic walls would be considered to be good building stones and, due to the costs of transport, these undoubtedly reflect the local geology. Looking down into the auditorium, the colours of the stones, which have been used to construct the principal architectural elements of the theatre, are completely different to those used in the rough walls.
 |
| A view of the Auditorium |
Entering the theatre, having passed through the museum, a close look shows that the steps are made from the blue-grey Piedra de Cabezo marble, the red travertine used in the columns is from Mula and the stage has been reconstructed in sandstone from the quarries at nearby Las Lomas de Canteras - a site that is now protected in law for its immense cultural value.
The Romans knew their building stones well and it is no surprise to discover that the marble, to carve the Corinthian capitals, was imported from Carrara, where whole mountain sides have been cut away to supply the worldwide demand for this stone - since ancient times.
 |
| The Old Cathedral - Santa María la Vieja |
The philosophy
behind the restoration has been to recycle original materials
and reconstruct pre-existing features with the same techniques and materials that the Romans would have used.
The new masonry and reconstructed
structural elements are generally clearly distinguishable from the original masonry, where
this is left in situ, but there are certain parts of the structure where it is not
so obvious where it has been conserved or reconstructed.
For a standing buildings archaeologist, a close examination of the stone walls - their geology, shape, size, tool marks, bonding and juxtaposition - can help to unravel the construction history of a monumental structure like this and, wandering around the theatre, there are many places where this can be studied.
 |
| Outcrops of quartzite and phyllite |
In my experience, there is often some confusion about the work of a geologist and an archaeologist; they both like to dig down into the Earth, to see what they can find, but it is the rocks that lay the foundations of the human history that developed upon them - a simple matter of chronological order.
Beneath the perimeter wall, a
couple of small
outcrops of the bedrock itself can be seen. The sheared and fractured nature of the quartzite and phyllite clearly make
them only suitable for use as rubble walling and they are highly
susceptible to weathering and erosion.
A lesson in geology could easily end here but, leaving the Roman theatre and descending to the entrance to get my bearings again, I encountered even more stones - Macael marble in the town hall, more polished Piedra de Cabezo marble in the street and multicoloured sandstone in the Muralla de Carlos III...
 |
| Various building and paving stones |
