Naslov
Current denudation rates of a dolostone karst over Eagle Cave, Central Spain

Autori
Krklec, Kristina ; Dominguez-Villar, David ; Carrasco, Rosa M ; Pedraza Javier

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

Izvornik
XIX INQUA Congress 2015 Quaternary Perspectives on Climate Change, Natural Hazards and Civilization / INQUA - Nagoya : International Union for Quaternary Research (INQUA), 2015

Skup
XIX INQUA Congress 2015 Quaternary Perspectives on Climate Change, Natural Hazards and Civilization

Mjesto i datum
Nagoya, Japan, 26.07.2015. - 02.08.2015

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
denudation ; carbonate corrosion ; karst ; rock weathering

Sažetak
Denudation of karst landscapes depends on the carbonate rocks weathering. Variability of weathering rates greatly depends on climate, lithology and other local parameters. Therefore, for evaluating the surface lowering of a karst terrain at a particular site, in situ measurements are required. We present preliminary data of karst denudation using the method of carbonate tablets. The method is applied to a karst terrain above Eagle Cave in central Spain. Two sets of tablets were buried at different depths (5-10 cm and 50-55 cm). Tablets were from six different dolostone cores sampled from the hill over Eagle Cave representing local lithological variability. In order to evaluate the replicability of results, several tablets of the same lithology were placed for every setting. Temperature and soil CO2 were continuously monitored for the two depths and meteorological data at the cave is available. Denudation rate at the depth of 5-10 cm resulted to be 2.48 ±1.07 mm/ka while average soil CO2 concentration was 2100 ±1200 ppm. At the depth of 50-55 cm, the denudation rate was 1.75 ±0.66 mm/ka while the average soil CO2 concentration was 10400 ±3200 ppm. As acidic solutions are expected to be less corrosive in the shallower setting as indicated by its lower CO2 concentration, other processes apart from dissolution contribute to the tablets weathering. We interpret that higher weathering rate near the surface is related to enhanced mechanical weathering on top of the carbonate corrosion. Although frost cycles do not affect the soil at the depth of 5-10 cm, other processes such as wetting-drying cycles and daily changes in temperature might be important. The denudation of karst will occur mostly in the soil-bedrock interface as a result of dissolution. Therefore, the weathering rate measured at the 50-55 cm depth is a more reliable value of denudation.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA