Holocene hydroclimate changes in continental Croatia recorded in speleothem δ 13 C and δ 18 O from Nova Grgosova Cave

Bibliographic Data

ID12267326
AuthorsMaša Surić (0000-0002-6266-158X, University of Zadar, corresponding author), Andrea Columbu (0000-0001-5410-062X, University of Bologna), Robert Lončarić (0000-0002-1045-5645, University of Zadar), Petra Bajo (0000-0002-0395-8113, Croatian Geological Survey, Croatia), Neven Bočić (0000-0001-6102-5330, University of Zagreb), Nina Lončar (0000-0003-0795-2832, University of Zadar), Russell N Drysdale (0000-0001-7867-031X, The University of Melbourne), John C Hellstrom (The University of Melbourne), J Hellstrom (0000-0001-9427-3525, The University of Melbourne)
Year2021
Volume31
Issue9
Pages1401-1416
Publication date2021-07-01
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenueThe Holocene (JOURNAL)
Journal identifiersISSN: 0959-6836 • E-ISSN: 1477-0911
PublisherSAGE Publishing (PUBLISHER • US)
DOI10.1177/09596836211019120
OpenAlexW3176822166
LanguageEN
Citations received3
References cited131

We present the first stable isotope (δ 13 C and δ 18 O) speleothem record from continental Croatia retrieved from two coeval stalagmites from Nova Grgosova Cave. U-Th dates constrain the stalagmite growth history from 10 ka to the present, revealing coeval growth between 7.8 and 5.6 ka. We interpret δ 18 O as an autumn/winter hydrological proxy related to changes of vapor source, precipitation amount, and/or seasonal rainfall distribution, while δ 13 C predominantly responds to spring/summer vegetation status and soil microbial activity. We identify several centennial to millennial-scale hydroclimate oscillations during this period that result from multiple forcing factors. Along with amount and source effect, it appears that some centennial variations were governed also by seasonal moisture balance. From 9.2 to 8.8 ka BP, the local environmental setting was characterized by enhanced vegetation activity, while during the 8.2 ka event the main feature was a change in precipitation seasonality. The most prominent change, identified in both δ 13 C records, is a sudden decline of vegetation and soil biological activity around 7.4 ka, indicating a precipitation decrease at a time of maximum plant growth in spring and summer and likely also reduced precipitation in autumn and winter. Although small in magnitude in these speleothems, a peak in δ 18 O and δ 13 C values at 4.3–4.1 ka suggests that both summer and winter conditions were substantially drier during the 4.2 ka event, in accordance with increased Mediterranean aridity and consistent with other global climate changes reported at this time. Compared to the present North Atlantic Oscillation (NAO) influence, we assume that millennial Holocene NAO-like variations were persistent through the Holocene via their effect on modifying local/regional air temperature, vapor origin, and inter- and intrannual precipitation distribution. Anthropogenic deforestation, which was the first major human impact on the environment during the Neolithic agricultural revolution, is excluded as a leading factor in δ 13 C variability since the first sedentary settlements were established further to the east in more arable locations along river valleys. However, the impact of intensive mining around the cave site during the last millennium is evident, with substantial deforestation driving an increase in δ 13 C

Archaeology · Cave · Climate change · Climatology · Geography · Holocene · Ice core · Mediterranean climate · Paleoclimatology · Physical geography · Precipitation · Speleothem · Stalagmite · Environmental Science · Geological formations and processes · Geology and Paleoclimatology Research · Maritime and Coastal Archaeology · Geology · Oceanography