Naslov
Cave air CO2 variations in Modrič Cave and implications for palaeoclimate studies

Autori
Surić, Maša ; Lončarić, Robert

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

Izvornik
Man and Karst 2022, Book of abstracts / Ruggieri, Rosario - Ragusa : CIRS, Ragusa, 2022, 58-58

Skup
Man and karst

Mjesto i datum
Custonaci, Italija, 12.09.2022. - 17.09.2022

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
cave, palaeoclimate, CO2, Croatia

Sažetak
Carbon dioxide (CO2) plays an important role in overall Earth’s system, as well as in karst underground environment, governing both limestone dissolution and speleothem deposition. Since the speleothems serve as a very valuable archive of the palaeoenvironmental setting, it is essential to comprehend the consequences of variation of CO2 concentration (CDC) on speleothem records. Namely, oxygen and carbon stable isotope ratios (δ18O and δ13C) of the spelean carbonate are recognized as proxies for autumn/winter conditions linked to the rainfall amount variability in the past and for spring/summer bioproductivity (i.e. microbial activity and vegetation density), respectively. So the dominant isotopic signal can be anchored only to the certain period of the year, which depends on cave air CDC. Based on periodical (2017-2022) and continuous (2021-2022) measurement of cave air CDC in Modrič Cave, we determined chimney-effect driven ventilation, controlled by seasonal differences between surface and cave air temperatures. Winter (Tout<Tcave) and summer (Tout>Tcave) ventilation regime are modulated by the cave passages geometry, transmissivity of the overlaying epikarst, and occasionally by the external winds, especially gusty north-eastern bora wind. Complementary to these measurements, we conducted two-months-interval collecting of the modern calcite on the glass plates, which indicated coinciding of (non)deposition of carbonate during the (high)low cave air CDC. So, for the reliable interpretation of speleothem isotopic records, this must be taken in serious consideration.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Interdisciplinarne prirodne znanosti

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