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| The hills in Cartagena |
Looking
out from El Teatro Romano, you get such a good impression of Cartagena – and
why it was so coveted in the ancient history of the Mediterranean region. However, having spent only 5 hours in the city, much of which time was spent wandering around without any real sense of direction or purpose, I barely scratched the surface of its geological and archaeological history.
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| The Geology of Cartagena |
Apart from the obviously regionally metamorphosed rock that I came across within the Roman theatre, I saw only one other rocky outcrop as I passed La Colina de Despeñaperros - one of
the five hills within the Muralla de Carlos III. I just recall a jumble of angular rocks, both natural and those that formed part of its walls, which were weathered and eroding – with muddy colours ranging from red, orange, yellow, green and purple
- to pink.
Cartagena
is well known for its archaeological remains, as I inadvertently discovered, but I had to wait until I undertook some internet research in England, before I could make sense of its geology. The maps available to me show the city as undifferentiated
Quaternary deposits, which is clearly not supported by the field evidence, as seen in the Roman theatre - at least.
As a student of the Spanish language, I have tried to plough my way through some of the academic publications that describe the general geological history of the region, but I have made much more progress using the resources of Google Map.
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| Calle Gisbert |
Zooming
in, each hill shows outcrops of pale coloured rock, remodelled
with walls but with similar physical characteristics. Street View shows
that the rock faces are just crumbling away.
Along Calle Gisbert, which bisects La Colina de la Concepción
and La Colina de Despeñaperro, the
road cutting exposes metamorphic rock similar to that seen in the
Roman theatre.
The inherent structural instability of this rock is reflected in the various geotechnical engineering works that have been undertaken here - rock netting, large retaining walls and other measures to keep the street safe from falling rock. Wandering back to the bus station, down Subida San José, I should have noticed similar geology but, in reality, I was more concerned about finding something to eat and drink, after a very long walk.
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A View Along Subida San José
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After
a lot of research, I have a reasonable theoretical understanding of the geology
in Cartagena and the metamorphosed Triassic rocks that comprise the mountains which
flank its harbour - but the precise geology of the five hills still remains a bit of a
mystery...