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Mónika Tóth Enikő K. Magyari Stephen J. Brooks Mihály Braun Krisztina Buczkó Miklós Bálint Oliver Heiri 《Quaternary Research》2012,77(1):122-131
Late glacial and early Holocene summer temperatures were reconstructed based on fossil chironomid assemblages at Lake Brazi (Retezat Mountains) with a joint Norwegian–Swiss transfer function, providing an important addition to the late glacial quantitative climate reconstructions from Europe. The pattern of the late glacial temperature changes in Lake Brazi show both similarities and some differences from the NGRIP δ18O record and other European chironomid-based reconstructions. Our reconstruction indicates that at Lake Brazi (1740 m a.s.l.) summer air temperature increased by ~ 2.8°C at the Oldest Dryas/Bølling transition (GS-2/GI-1) and reached 8.1–8.7°C during the late glacial interstade. The onset of the Younger Dryas (GS-1) was characterized by a weak (< 1°C) decrease in chironomid-inferred temperatures. Similarly, at the GS-1/Holocene transition no major changes in summer temperature were recorded. In the early Holocene, summer temperature increased in two steps and reached ~ 12.0–13.3°C during the Preboreal. Two short-term cold events were detected during the early Holocene between 11,480–11,390 and 10,350–10,190 cal yr BP. The first cooling coincides with the Preboreal oscillation and shows a weak (0.7°C) temperature decrease, while the second is characterized by 1°C cooling. Both cold events coincide with cooling events in the Greenland ice core records and other European temperature reconstructions. 相似文献
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Moisture source diagnostics and isotope characteristics for precipitation in east Hungary: implications for their relationship 总被引：1，自引：0，他引：1
Knowledge relating to the relationship between the characteristics of precipitation and sources of moisture is essential to improve our understanding of the global water cycle. This study presents the first quantitative estimation of the moisture source regions combined with stable isotope analyses for precipitation at K-puszta, east Hungary. The contributions of the following moisture sources were diagnosed according to the sector analysis of 4-day backward trajectories together with the calculation of evaporation and precipitation fluxes based on the specific humidity: Mediterranean region (57.0%), local moisture (14.8%), Atlantic region (14.2%), Northern Europe (7.4%) and Eastern Europe (6.6%). The δD and δ18O values of daily precipitation were measured and the deuterium excess (d-excess) was calculated. The d-excess showed systematic differences among the marine sources, reflecting the characteristics of the moisture source area. The results suggest that the stable isotope composition of precipitation preserves information regarding the origin of the water vapour. 相似文献
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Krisztina Buczkó Enik? Magyari Thomas Hübener Mihály Braun Miklós Bálint Mónika Tóth André F. Lotter 《Journal of Paleolimnology》2012,48(2):417-431
A high-resolution paleolimnological study from Lake Brazi, a small mountain lake in the Southern Carpathian Mountains, Romania, shows distinct diatom responses to late glacial and early Holocene climate change between ca. 15,750 and 10,000?cal?year BP. Loss-on-ignition, titanium, sulphur, phosphorus, biogenic silica content, and diatom assemblage composition were used as proxies for past environmental changes. Total epilimnetic phosphorus (TP) concentrations and lakewater pH were reconstructed quantitatively using diatom-TP and pH transfer functions. The most remarkable changes in the aquatic ecosystem were found at ca. 12,870 and 10,400?cal?year BP. Whereas the onset of the Younger Dryas (YD) climatic reversal was conspicuous in our record, the beginning of the Holocene was not well marked. Two diatom assemblage zones characterize the YD in Lake Brazi, suggesting a bipartite division of this climatic oscillation. The diatom responses to the YD cooling were (1) a shift from Staurosira venter to Stauroforma exiguiformis dominance; (2) a decrease in overall diatom diversity; (3) a decrease in lake productivity, inferred from DI-TP, organic matter, and biogenic silica content; and (4) a lowering of the DI-pH. Compositional change of the diatom assemblages suggested a sudden shift towards more acidic lake conditions at 12,870?cal?year BP, which is interpreted as a response to prolonged ice cover and thus shorter growing seasons and/or enhanced outwash of humic acids from the catchment. Taking into account the chironomid-based inference of only moderate July mean temperature decrease (<1?°C), together with the pollen-inferred regional opening of the forest cover and expansion of steppe-tundra, our data suggest that ecosystem changes in the Southern Carpathians during the YD were likely determined by strong seasonal changes. 相似文献
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Pozsgai Emília Józsa Sándor Dunkl István Sebe Krisztina Thamó-Bozsó Edit Sajó István Dezső József von Eynatten Hilmar 《International Journal of Earth Sciences》2017,106(6):2005-2024
International Journal of Earth Sciences - The Tisza Megaunit in the Southern Pannonian Basin formed part of the southern margin of the European Plate in the Early Mesozoic era. Its exact... 相似文献
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Zoltán Püspöki Philip L. Gibbard László Ferenc Kiss Richard W. McIntosh Edit Thamó-Bozsó Zita Krassay Bálint Szappanos Vera Maigut Péter Kovács Dominik Karácsony Ferenc Stercel Ferenc Visnovitz Krisztina Demény László Bereczki Teodóra Szőcs Ágnes Rotár-Szalkai Tamás Fancsik 《Boreas: An International Journal of Quaternary Research》2023,52(3):402-426
Magnetic susceptibility (MS) of the Quaternary long-term mid-latitude Maros fluvial fan (Pannonian Basin) was recorded to understand the stratigraphical features of source-proximal fluvial depositional settings. Three fully cored 500-m-deep boreholes were sampled at 0.5-m intervals; low-field and frequency dependent MS were measured, and complementary hysteresis and SEM-EDAX investigations were performed on selected samples. Logged susceptibility data were also used to log correlations established by a simultaneous comparison of wireline log and laboratory measurements. Time-series analyses of the susceptibility records reveal a ~41-ka and ~100-ka cyclicity. Towards the source-distal sections the intensity of the ~41-ka cycles decreases, while that of the ~100-ka cycles remains strong. Stratigraphical and spectral similarities were observed between the Maros fluvial fan and Chinese loess records; however, based on complementary magnetic data, the magnetic phase of the Maros Fan sections is related to the detrital magnetite that originates from the catchment during early postglacial permafrost degradations. The amplification of the ~41-ka cycles can be attributed to the very high susceptibility values in source-proximal settings and to the special stratigraphical feature of the distributive fluvial systems. This comprises the increased avulsion frequency on the fluvial fans in ‘glacial recession periods’, in concert with the ‘early postglacial’ occurrence of the permafrost-related magnetite originating from the catchment. As a local phenomenon, this is significant since it records the obliquity-driven variations in permafrost development in a catchment. However, fluvial and alluvial fans are widespread depositional landforms within the Eurasian mountain range and were possibly the same during the Quaternary deglaciations. Thus, obliquity-driven magnetic susceptibility variations in source-proximal fan deposits attached or adjacent to regions of loess deposition should also be considered when scanning for potential source material of aeolian deposits. 相似文献
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GeoJournal - Building on the insights of scholarship highlighting specific aspects of the forming of place meanings and experiences during running (events), this paper aims at applying a more... 相似文献
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