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- ItemProminent role of volcanism in Common Era climate variability and human history(Jena : Urban & Fischer, 2020) Büntgen, Ulf; Arseneault, Dominique; Boucher, Étienne; Churakova, Olga V.; Gennaretti, Fabio; Crivellaro, Alan; Hughes, Malcolm K.; Kirdyanov, Alexander V.; Klippel, Lara; Krusic, Paul J.; Linderholm, Hans W.; Ljungqvist, Fredrik C.; Ludescher, Josef; McCormick, Michael; Myglan, Vladimir S.; Nicolussi, Kurt; Piermattei, Alma; Oppenheimer, Clive; Reinig, Frederick; Sigl, Michael; Vaganov, Eugene A.; Esper, JanClimate reconstructions for the Common Era are compromised by the paucity of annually-resolved and absolutely-dated proxy records prior to medieval times. Where reconstructions are based on combinations of different climate archive types (of varying spatiotemporal resolution, dating uncertainty, record length and predictive skill), it is challenging to estimate past amplitude ranges, disentangle the relative roles of natural and anthropogenic forcing, or probe deeper interrelationships between climate variability and human history. Here, we compile and analyse updated versions of all the existing summer temperature sensitive tree-ring width chronologies from the Northern Hemisphere that span the entire Common Era. We apply a novel ensemble approach to reconstruct extra-tropical summer temperatures from 1 to 2010 CE, and calculate uncertainties at continental to hemispheric scales. Peak warming in the 280s, 990s and 1020s, when volcanic forcing was low, was comparable to modern conditions until 2010 CE. The lowest June–August temperature anomaly in 536 not only marks the beginning of the coldest decade, but also defines the onset of the Late Antique Little Ice Age (LALIA). While prolonged warmth during Roman and medieval times roughly coincides with the tendency towards societal prosperity across much of the North Atlantic/European sector and East Asia, major episodes of volcanically-forced summer cooling often presaged widespread famines, plague outbreaks and political upheavals. Our study reveals a larger amplitude of spatially synchronized summer temperature variation during the first millennium of the Common Era than previously recognised.
- ItemCyclostratigraphy and paleoenvironmental inference from downhole logging of sediments in tropical Lake Towuti, Indonesia(Dordrecht [u.a.] : Springer Science + Business Media B.V, 2021) Ulfers, A.; Hesse, K.; Zeeden, C.; Russell, J.M.; Vogel, H.; Bijaksana, S.; Wonik, T.Lake Towuti is located on central Sulawesi/Indonesia, within the Indo Pacific Warm Pool, a globally important region for atmospheric heat and moisture budgets. In 2015 the Towuti Drilling Project recovered more than 1000 m of drill core from the lake, along with downhole geophysical logging data from two drilling sites. The cores constitute the longest continuous lacustrine sediment succession from the Indo Pacific Warm Pool. We combined lithological descriptions with borehole logging data and used multivariate statistics to better understand the cyclic sequence, paleoenvironments, and geochronology of these sediments. Accurate chronologies are crucial to analyze and interpret paleoclimate records. Astronomical tuning can help build age-depth models and fill gaps between age control points. Cyclostratigraphic investigations were conducted on a downhole magnetic susceptibility log from the lacustrine facies (10–98 m below lake floor) from a continuous record of sediments in Lake Towuti. This study provides insights into the sedimentary history of the basin between radiometric ages derived from dating a tephra layer (~ 797 ka) and C14-ages (~ 45 ka) in the cores. We derived an age model that spans from late marine isotope stage (MIS) 23 to late MIS 6 (903 ± 11 to 131 ± 67 ka). Although uncertainties caused by the relatively short record and the small differences in the physical properties of sediments limited the efficacy of our approach, we suggest that eccentricity cycles and/or global glacial-interglacial climate variability were the main drivers of local variations in hydroclimate in central Indonesia. We generated the first nearly complete age-depth model for the lacustrine facies of Lake Towuti and examined the potential of geophysical downhole logging for time estimation and lithological description. Future lake drilling projects will benefit from this approach, since logging data are available just after the drilling campaign, whereas core descriptions, though more resolved, only become available months to years later.
- ItemCharacterization of Zahari Zograph’s nave wall paintings in the church “The nativity of the virgin” of Rila Monastery (Bulgaria) by vibrational spectroscopy and SEM–EDX analysis(Abingdon, Oxon : Routledge, Taylor and Francis Group, 2018) Yancheva, Denitsa; Tapanov, Stefan; Velcheva, Evelina; Stamboliyska, Bistra; Glavcheva, Zornitza; Stoyanov, Simeon; Haralampiev, Nikifor; Fischer, Dieter; Lederer, AlbenaAn analytical study on the nave mural paintings of the church “The Nativity of the Virgin” of Rila monastery, Bulgaria, painted by Zahari Zograph was carried out. Vibrational spectroscopy was applied to identify the pigments and organic materials used in the mural paintings. To complement the spectral information, elemental composition of the samples was determined by SEM-EDX. The data showed that smalt with carbohydrate binder was applied for the blue background, green colour was executed by green earths and red-orange colour – by red lead. Azurite is the pigment used to paint the blue colour of the saints’ hoods. The mordant for gilding was prepared of drying oil, resin and siccative metal oxides as evidenced by SEM-EDX, ATR-FTIR and pyrolysis GC-MS analysis. The use of azurite is related to Zahari Zograph’s works as it was not found in any of the previously studied murals in the church painted by other artists.
- ItemMulti-method study of the Middle Pleistocene loess-palaeosol sequence of Köndringen, SW Germany(Göttingen : Copernicus, 2023) Schwahn, Lea; Schulze, Tabea; Fülling, Alexander; Zeeden, Christian; Preusser, Frank; Sprafke, TobiasLoess-palaeosol sequences (LPSs) remain poorly investigated in the southern part of the Upper Rhine Graben but represent an important element to understand the environmental context controlling sediment dynamics in the area. A multi-method approach applied to the LPS at Köndringen reveals that its formation occurred during several glacial-interglacial cycles. Field observations, as well as colour, grain size, magnetic susceptibility, organic carbon, and carbonate content measured in three profiles at 5 cm resolution, provide detailed stratigraphical information. Only minor parts of the LPS are made up of loess sediment, whereas the major parts are polygenetic palaeosols and pedosediments of varying development that are partly intersected, testifying to a complex local geomorphic evolution. The geochronological framework is based on 10 cm resolution infrared-stimulated luminescence (IRSL) screening combined with 18 multi-elevated-temperature post-IR IRSL ages. The luminescence ages indicate that two polygenetic, truncated Luvisols formed during marine isotope stages (MISs) 9(-7?) and MIS 5e, whereas unaltered loess units correspond to the last glacial (MISs 5d-2) and MIS 8. The channel-like structure containing the two truncated Luvisols cuts into > 2 m thick pedosediments apparently deposited during MIS 12. At the bottom of the LPS, a horizon with massive carbonate concretions (loess dolls) occurs, which may correspond to at least one older interglacial.
- ItemClosing the loop: Reconnecting human dynamics to Earth System science(London [u.a.] : Sage, 2017) Donges, Jonathan F.; Winkelmann, Ricarda; Lucht, Wolfgang; Cornell, Sarah E.; Dyke, James G.; Rockström, Johan; Heitzig, Jobst; Schellnhuber, Hans JoachimInternational commitment to the appropriately ambitious Paris climate agreement and the United Nations Sustainable Development Goals in 2015 has pulled into the limelight the urgent need for major scientific progress in understanding and modelling the Anthropocene, the tightly intertwined social-environmental planetary system that humanity now inhabits. The Anthropocene qualitatively differs from previous eras in Earth’s history in three key characteristics: (1) There is planetary-scale human agency. (2) There are social and economic networks of teleconnections spanning the globe. (3) It is dominated by planetary-scale social-ecological feedbacks. Bolting together old concepts and methodologies cannot be an adequate approach to describing this new geological era. Instead, we need a new paradigm in Earth System science that is founded equally on a deep understanding of the physical and biological Earth System – and of the economic, social and cultural forces that are now an intrinsic part of it. It is time to close the loop and bring socially mediated dynamics explicitly into theory, analysis and models that let us study the whole Earth System.