Póster elaborado para la European Geosciences Union General Assembly, celebrada en Viena del 8 al 13 de abril de 2018

Arteche García, José Luis

Celaya, Santiago

Fernández, Alicia

Fernández, Enrique

Fuente Merino, Ismael

Quindós López, Luis

Quindós Poncela, Luis Santiago

Quindós, Jorge

Rábago, Daniel

Sainz, Carlos

English

Fernández López, Enrique

Agencia Estatal de Meteorología

The use of tracer gases to study the air exchange in the Altamira caveDaniel Rabago1         , Carlos Sainz1-2, Santiago Celaya1-2, Enrique Fernandez1, Jorge Quindos1, Luis Quindos1, Alicia Fernandez1, Ismael Fuente1, Jose Luis Arteche3, Luis S. Quindos1-21 Radon Group. University of Cantabria. C/Cardenal Herrera Oria s/n 39011, Santander, Spain2 The Cantabrian International Institute for Prehistoric Research (IIIPC) 3 Spanish Meteorological Agency, AEMETdaniel.rabago@unican.esAltamira CaveMethodology» Located in Santillana del Mar, Cantabria, northern Spain» Main Ancient rock art dating back about 15,000 years» World Heritage site by UNESCO (1985, list no. 310)» Shallow cave with an absolute height difference between entrance and deepest part (Well Room) of ~ 16 meters.   » Exchange rate Q calculated from simplified model of Wilkening: Radonconcentration in a chamber varies according to the quantity emitted through thesurface of the rocks, the quantity that disappears by disintegration, and thevariations produced by exchange with air masses containing differentconcentrations from other chambers and/or the outside atmosphere.Conclusions» The distribution of radon concentration reflects the air exchange rates in the cave» Main gaseous charge-discharge processes occur seasonally at Altamira cave» High correlation found between seasonally, short term gases variation and Δρ» Rn and CO2 continuous monitoring is a key tool for studying atmospheric dynamics» Radon presents simpler mechanisms as tracer than CO2Results» Cave temperature is result of thermal wave propagation through the rock» Amplitude attenuation» Delay with respect to the outer wavePolychromes RoomGrave RoomWell RoomHallCrossingExteriorStation of environmental parameters Air temperature: Pt100 probes – Mercury in glass thermometerCO2 concentration: EE82 Series instrumentAir pressure: Pressure sensor Delta OHM HD 9408[CO2] (ppm) CRn (Bq/m3)ΔP (Ext.-Hall) -0.28 -0.34Δρ (Ext.-Hall) 0.77 0.75ΔT (Ext.-Hall) -0.79 -0.76ΔP (Ext.-Poly.) -0.53 -0.51Δρ (Ext.-Poly.) 0.80 0.82ΔT (Ext.-Poly.) -0.81 -0.82Air temperature at half height inside and outside the caveVentilation rate Q (m3/h) between Polychromes Room and the outsideIIIIIIIVLinear correlation coefficientPressure P (hPa) ; Air density ρ (kg/m3) ; Temperature T (ᵒC)Differences in T, P and ρ of the air between the Exterior and the Hall and Exterior and Polychromes Room.CO2 and Rn concentration in the Hall and Polychromes» Greater ventilation rate in summer due to high air density differences between exterior and cave» Degasification: Denser air inside the cave tends to descend to lower levels through the pores and cracks of the karst» Recharge: Denser air outside along with the moisture increment in soil block outputs and air exchange𝑄𝑄 = λ · 𝑉𝑉 𝐶𝐶max − 𝐶𝐶𝐶𝐶 − 𝐶𝐶𝐶λ : radon disintegration constant (0.0076 h-1)V : volume of Polychromes Room (~ 340 m3)C : radon concentrationC’ : radon concentration in chamber which it exchanges (Outside C’ ≈ 0)Cmax : maximum annual radon concentration in the room(1)Continuous and integrated radon monitoringTrack etch detectors CR-39Radon Scout monitor (Sarad GmbH)» Seasonal gases variation: Degasification in summer » High correlation between air temperature and air density differences between rooms and outsideρext < ρcave  DegasificationReferencesVFernandez et al. 1986. Natural ventilation of the paintings room in the Altamira caveQuindós at al. 1991. National survey on indoor radon in SpainSainz et al. 2018. Continuous monitoring of radon gas as a tool to understand air dynamics in the cave of Altamira (Cantabria, Spain)Sánchez-Moral et al. 2009. Estudio integral del estado de conservación de la Cueva de Altamira y sus representaciones artísticas paleolíticasρext > ρcave  RechargeExterior       Hall Crossing Polychromes Grave Room Well RoomView publication stats

The use of tracer gases to study the air exchange in the Altamira cave

https://repositorio.aemet.es/bitstream/20.500.11765/11789/1/Use_Tracer_Rabago.pdf

The use of tracer gases to study the air exchange in the Altamira cave

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