Naslov
Dating an episode of paleo-condensation corrosion in Eagle Cave (Spain)

Autori
Domínguez-Villar, David ; Krklec, Kristina ; Cheng, Hai ; Edwards, Lawrence R.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
24th International Karstological School "Classical Karst" Paleokarst: abstracts & guide book / Otoničar, Bojan ; Gostinčar, Petra - Ljubljana : ZRC Publishing, 2016, 17-18

ISBN
978-961-254-914-5

Skup
24th International Karstological School "Classical Karst": Paleokarst

Mjesto i datum
Postojna, Slovenija, 13.06.2016. - 17.06.2016

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
condensation corrosion ; cave collapse ; cave ventillation ; U-Th dating ; speleothems

Sažetak
Eagle Cave is a small tourist cave from central Spain. In this cave, aragonite speleothems frequently show a distinctive red/orange colour with unusual blunt edges, exposed laminations and occasionally large holes through them. On the other hand, white calcite speleothems show more traditional shapes and textures. The later speleothems clearly postdate the former aragonite speleothems, and both speleothem stages are easy to identify. Fresh cuts of aragonite speleothems show that the red/orange colour is just a thin coat on their surface. During the first stage, the environmental conditions favoured aragonite precipitation of speleothems. However, a later event caused condensation corrosion all over the cave, partly dissolving speleothems. Low relative humidity during this period favoured the advection of aerosols (mostly clay-size oxide particles) that coated cave walls and speleothems. This sudden environmental change is likely the result of a significant collapse that dramatically changed the cave ventilation. At some point the cave environmental conditions changed again and speleothems were formed once more. Change in speleothem mineralogy from aragonite to calcite indicates that ventilation did not return to the initial conditions and cave CO2 was likely higher. U-Th dates of four different speleothems were obtained for samples above and below the “red layer” that indicated the collapse. The cave collapse occurred soon after 60 ka BP and open conditions lasted only some thousand years. This collapse story is in agreement with the record of multiple collapses of different magnitudes within the cave and with the karst record at the surface where unroofed caves are found.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA