Stable Isotope Hydrology of Cave Groundwater and Its Relevance for Speleothem-Based Paleo-Environmental Reconstruction in Croatia

Speleothems deposited from cave drip waters retain, in their calcite lattice, isotopic records of past environmental changes. Among other proxies, δ18O is recognized as very useful for this purpose, but its accurate interpretation depends on understanding the relationship between precipitation and d...

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Bibliographic Details
Published in:Water (Basel) 2020-01, Vol.12 (9), p.2386
Main Authors: Surić, Maša, Czuppon, György, Lončarić, Robert, Bočić, Neven, Lončar, Nina, Bajo, Petra, Drysdale, Russell N
Format: Article
Language:English
Subjects:
Aquifers
Archives & records
Calcite
Caves
Chemical precipitation
Coasts
Cold
Elevation
Environmental changes
Evaporation
Fractionation
Glacial periods
Groundwater
Hydrology
Influence
Karst
Precipitation
Rain
Rainfall
Stable isotopes
Summer
Weather
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Summary:Speleothems deposited from cave drip waters retain, in their calcite lattice, isotopic records of past environmental changes. Among other proxies, δ18O is recognized as very useful for this purpose, but its accurate interpretation depends on understanding the relationship between precipitation and drip water δ18O, a relationship controlled by climatic settings. We analyzed water isotope data of 17 caves from different latitudes and altitudes in relatively small but diverse Croatian karst regions in order to distinguish the dominant influences. Drip water δ18O in colder caves generally shows a greater resemblance to the amount-weighted mean of precipitation δ18O compared to warmer sites, where evaporation plays an important role. However, during glacial periods, today’s ‘warm’ sites were cold, changing the cave characteristics and precipitation δ18O transmission patterns. Superimposed on these settings, each cave has site-specific features, such as morphology (descending or ascending passages), altitude and infiltration elevation, (micro) location (rain shadow or seaward orientation), aquifer architecture (responsible for the drip water homogenization) and cave atmosphere (governing equilibrium or kinetic fractionation). This necessitates an individual approach and thorough monitoring for best comprehension.
ISSN:2073-4441
DOI:10.3390/w12092386