11. An early glacial maximum during the last glacial cycle on the northern Velebit Mt. (Croatia)Manja Žebre, Mehmet Akif Sarikaya, Uroš Stepišnik, Renato R. Colucci, Cengiz Yildirim, Attila Çiner, Adem Candaş, Igor Vlahović, Bruno Tomljenović, Bojan Matoš, Klaus M. Wilcken, 2021, izvirni znanstveni članek Povzetek: Comprehensive glacial Quaternary studies involving geochronological methods, modelling of ice topography with the support of field geomorphological and geological data in the Balkan Peninsula are relatively scarce, although there is evidence of past glaciations in several mountain ranges. Here, we present research on the extent and timing of past glaciations on the northern Velebit Mt. in coastal Croatia and inferences of the climate during that time. Based on geomorphological and sedimentological evidence and using cosmogenic 36Cl surface exposure dating of moraine boulders, we provide an empirical reconstruction of past glaciers and compare this with the Parallel Ice Sheet Model (PISM) simulations under different palaeoclimate forcings. The dating results show that the northern Velebit glaciers reached their maximum extent during the last glacial cycle before the global Last Glacial Maximum (LGM). Maximum ice extent likely correlates with Marine Isotope Stage 5–4, although the exact timing cannot be determined at this point due to poorly known site- and time-specific denudation rates. Empirical reconstruction of the maximum extent suggests that the area covered by glaciers was ~116 km2. The-best fit PISM simulation indicates that the most likely palaeoclimate scenario for the glaciers of this size to form is a cooling of ~8 °C and a 10% reduction in precipitation from present-day levels. However, the best-fit simulation does not correctly model all mapped ice margins when changes in climatological parameters are applied uniformly across the model domain, potentially reflecting a different palaeoprecipitation pattern to today.
Ključne besede: Pleistocene, cosmogenic isotopes, glacial geomorphology, Dinarides, PISM
Objavljeno v DiRROS: 04.03.2022; Ogledov: 836; Prenosov: 324
 Celotno besedilo (14,52 MB) |
12. Examination of stable carbon and oxygen isotopic variability in the cellulose and wholewood of Castanea sativa Mill., Fagus sylvatica L., Pinus sylvestris L. and Quercus robur L.B. Sladden, N.J. Loader, G.H.F. Young, D. McCarroll, 2018, izvirni znanstveni članek Povzetek: This paper presents results from a comparison of wholewood and cellulose carbon and oxygen isotope ratios for four UK tree species. These species occur within the historic buildings archive as both primary and supplementary construction materials and have been used to reconstruct the climate of the past. New advances in the application of stable isotopes have widened the scope of the isotope approach, but require the time-consuming purification of cellulose. Comparison of the oxygen and carbon isotope signals preserved in the wood and cellulose components confirms and builds upon previous research in this field and provides additional insight into the covariance of these two sample types between species, an
Ključne besede: stable isotopes, tree ring, dendrochronology, dendroclimatology
Objavljeno v DiRROS: 04.02.2019; Ogledov: 5482; Prenosov: 3526
Celotno besedilo (1,63 MB)
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