 |
| Titel |
Multiparametric surveillance of conservation measures at subterranean rock-art sites: case of Altamira cave |
| VerfasserIn |
E. Garcia-Anton, S. Cuezva, A. Fernandez-Cortes, S. Sanchez-Moral, J. C. Canaveras |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250058991
|
|
|
|
|
|
| Zusammenfassung |
| Altamira cave (North of Spain) contains one of the most worldwide important representations
of Palaeolithic art. Changes introduced in the cave environment due to the numerous
conditioning projects and massive amounts of visitors in the past led in severe disruptions on
the pattern of energy-matter exchange with the external atmosphere.
Once the Altamira Cave was definitely closed to visitors in 2002, several conservation
actions were progressively carried out with the aim to reinforce the isolation of the main cave
emplacement with rock art (Polychrome Hall) and, therefore, limiting the dispersion of
microorganisms and the supply of nutrients by airflow, water condensation on rock surfaces
or seepage water. Main preservation measure was the installation of new access doors
equipped with a thermal insulation system.
Multi-annual instrumental monitoring of the atmosphere-soil-cave system has allowed us
to control the degree of environmental recovery of cave environment and its trend towards the
equilibrium and quasi-natural conditions. The monitoring program was focused on the main
microclimatic parameters (air temperature, relative humidity, carbon dioxide, radon, air
velocity, among others) in several profiles from floor to ceiling along the main rooms of the
cave.
Since the entrance system was modified in 2008 several changes in cave environment
have been registered. Absolute annual values of temperature, velocity of air and their annual
ranges variation have progressively been reduced. Observed 222Rn and CO2 convective short
period fluctuations have been reduced, mainly during the winter season. The beginning
of the degassing period in the cave has been delayed. Differences between inner
and outer zones of the cavity have increased reaching the maximum value during
the summer season (period of greater connexion with outside environment). For
instance: in Polychrome Hall the range temperature falls from 1.41oC in 2007-2008
to 1.28oC in 2010-2011; in Crossing Hall the maximum value of the air velocity
have been reduced from 0.2 m/s in the period 2007-2008 to 0.1 m/s in 2010-2011;
while in august 2008 the difference in 222Rn Concentration between Polychrome
Hall and the Entrance was 28 Bq/m3, in august 2011 the difference reached 379
Bq/m3.
Those facts point to a lower interchanging ratio between outside and inside the
cave that means a microclimatic situation closer to the natural conditions. As a
consequence the atmosphere of Polychromes hall operates as a motionless atmosphere
that does not take part in the aerodynamic exchange with the external atmosphere.
Thus, an air thermal stratification creates a static trap of warm and less dense air
inside cave that contributes to the gas entrapment process. The obtained results
reinforce the significance of the environmental monitoring program in order to
ensure the cave protection, as well as providing guidance on conservation strategies. |
|
|
|
|
|
|