33 results on '"Breitenbach, Sebastian F.M."'
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2. Characterising the decay of organic metal complexes in speleothem-forming cave waters
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Höpker, Sebastian N., Breitenbach, Sebastian F.M., Grainger, Megan, Stirling, Claudine H., and Hartland, Adam
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- 2024
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3. What we talk about when we talk about seasonality – A transdisciplinary review
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Kwiecien, Ola, Braun, Tobias, Brunello, Camilla Francesca, Faulkner, Patrick, Hausmann, Niklas, Helle, Gerd, Hoggarth, Julie A., Ionita, Monica, Jazwa, Christopher S., Kelmelis, Saige, Marwan, Norbert, Nava-Fernandez, Cinthya, Nehme, Carole, Opel, Thomas, Oster, Jessica L., Perşoiu, Aurel, Petrie, Cameron, Prufer, Keith, Saarni, Saija M., Wolf, Annabel, and Breitenbach, Sebastian F.M.
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- 2022
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4. Archaeological and environmental cave records in the Gobi-Altai Mountains, Mongolia
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Vanwezer, Nils, Breitenbach, Sebastian F.M., Gázquez, Fernando, Louys, Julien, Kononov, Aleksandr, Sokol'nikov, Dmitry, Avirmed, Erdenedalai, Burguet-Coca, Aitor, Picin, Andrea, Cueva-Temprana, Arturo, Sánchez-Martínez, Javier, Taylor, William Timothy Treal, Boivin, Nicole, Bayarsaikhan, Jamsranjav, and Petraglia, Michael D.
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- 2021
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5. Detecting and quantifying palaeoseasonality in stalagmites using geochemical and modelling approaches
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Baldini, James U.L., Lechleitner, Franziska A., Breitenbach, Sebastian F.M., van Hunen, Jeroen, Baldini, Lisa M., Wynn, Peter M., Jamieson, Robert A., Ridley, Harriet E., Baker, Alexander J., Walczak, Izabela W., and Fohlmeister, Jens
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- 2021
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6. Permafrost-related hiatuses in stalagmites: Evaluating the potential for reconstruction of carbon cycle dynamics
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Lechleitner, Franziska A., Mason, Andrew J., Breitenbach, Sebastian F.M., Vaks, Anton, Haghipour, Negar, and Henderson, Gideon M.
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- 2020
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7. Holocene interaction of maritime and continental climate in Central Europe: New speleothem evidence from Central Germany
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Breitenbach, Sebastian F.M., Plessen, Birgit, Waltgenbach, Sarah, Tjallingii, Rik, Leonhardt, Jens, Jochum, Klaus Peter, Meyer, Hanno, Goswami, Bedartha, Marwan, Norbert, and Scholz, Denis
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- 2019
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8. Coarse-grained cryogenic aragonite as end-member of mineral formation in dolomite caves
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Richter, Detlev K., Scholz, Denis, Jöns, Niels, Neuser, Rolf D., and Breitenbach, Sebastian F.M.
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- 2018
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9. Coupled Mg/Ca and clumped isotope analyses of foraminifera provide consistent water temperatures
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Breitenbach, Sebastian F.M., Mleneck-Vautravers, Maryline J., Grauel, Anna-Lena, Lo, Li, Bernasconi, Stefano M., Müller, Inigo A., Rolfe, James, Gázquez, Fernando, Greaves, Mervyn, and Hodell, David A.
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- 2018
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10. Quantification of paleo-aquifer changes using clumped isotopes in subaqueous carbonate speleothems
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Gázquez, Fernando, Columbu, Andrea, De Waele, Jo, Breitenbach, Sebastian F.M., Huang, Ci-Rong, Shen, Chuan-Chou, Lu, Yanbin, Calaforra, José-María, Mleneck-Vautravers, Maryline J., and Hodell, David A.
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- 2018
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11. Sr-isotope analysis of speleothems by LA-MC-ICP-MS: High temporal resolution and fast data acquisition
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Weber, Michael, Wassenburg, Jasper A., Jochum, Klaus Peter, Breitenbach, Sebastian F.M., Oster, Jessica, and Scholz, Denis
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- 2017
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12. Sensitivity of Bunker Cave to climatic forcings highlighted through multi-annual monitoring of rain-, soil-, and dripwaters
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Riechelmann, Sylvia, Schröder-Ritzrau, Andrea, Spötl, Christoph, Riechelmann, Dana Felicitas Christine, Richter, Detlev Konrad, Mangini, Augusto, Frank, Norbert, Breitenbach, Sebastian F.M., and Immenhauser, Adrian
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- 2017
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13. The political collapse of Chichén Itzá in climatic and cultural context
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Hoggarth, Julie A., Breitenbach, Sebastian F.M., Culleton, Brendan J., Ebert, Claire E., Masson, Marilyn A., and Kennett, Douglas J.
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- 2016
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14. Cave ventilation and rainfall signals in dripwater in a monsoonal setting – a monitoring study from NE India
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Breitenbach, Sebastian F.M., Lechleitner, Franziska A., Meyer, Hanno, Diengdoh, Gregory, Mattey, David, and Marwan, Norbert
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- 2015
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15. Hunting, herding, and people in the rock art of Mongolia: New discoveries in the Gobi-Altai Mountains
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Vanwezer, Nils, Timothy Treal Taylor, William, Bayarsaikhan, Jamsranjav, Breitenbach, Sebastian F.M., Amano, Noel, Louys, Julien, del Val, Miren, Boivin, Nicole, and Petraglia, Michael
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- 2021
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16. Climatic and in-cave influences on delta O-18 and delta C-13 in a stalagmite from northeastern India through the last deglaciation
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Lechleitner, Franziska A., Breitenbach, Sebastian F.M., Cheng, Hai, Plessen, Birgit, Rehfeld, Kira, Goswami, Bedartha, Marwan, Norbert, Eroglu, Deniz, Adkins, Jess, and Haug, Gerald
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Institut für Geowissenschaften ,Indian Summer Monsoon ,stalagmite ,oxygen isotopes ,carbon isotopes ,deglaciation - Abstract
Northeastern (NE) India experiences extraordinarily pronounced seasonal climate, governed by the Indian summer monsoon (ISM). The vulnerability of this region to floods and droughts calls for detailed and highly resolved paleoclimate reconstructions to assess the recurrence rate and driving factors of ISM changes. We use stable oxygen and carbon isotope ratios (delta O-18 and delta C-13) from stalagmite MAW-6 from Mawmluh Cave to infer climate and environmental conditions in NE India over the last deglaciation (16-6ka). We interpret stalagmite delta O-18 as reflecting ISM strength, whereas delta C-13 appears to be driven by local hydroclimate conditions. Pronounced shifts in ISM strength over the deglaciation are apparent from the delta O-18 record, similarly to other records from monsoonal Asia. The ISM is weaker during the late glacial (LG) period and the Younger Dryas, and stronger during the BOlling-Allerod and Holocene. Local conditions inferred from the delta C-13 record appear to have changed less substantially over time, possibly related to the masking effect of changing precipitation seasonality. Time series analysis of the delta O-18 record reveals more chaotic conditions during the late glacial and higher predictability during the Holocene, likely related to the strengthening of the seasonal recurrence of the ISM with the onset of the Holocene.
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- 2017
17. Climate dynamics during the penultimate glacial period recorded in a speleothem from Kanaan Cave, Lebanon (central Levant).
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Nehme, Carole, Verheyden, Sophie, Breitenbach, Sebastian F.m., Gillikin, David P., Verheyden, Anouk, Cheng, Hai, Edwards, R. Lawrence, Hellstrom, John, Noble, Stephen R., Farrant, Andrew R., Sahy, Diana, Goovaerts, Thomas, Salem, Ghada, and Claeys, Philippe
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GLACIATION ,STABLE isotope tracers ,SPELEOTHEMS ,OXYGEN content of seawater ,PETROLOGY ,STALACTITES & stalagmites - Abstract
Little is known about terrestrial climate dynamics in the Levant during the penultimate interglacial-glacial period. To decipher the palaeoclimatic history of the Marine Oxygen Isotope Stage (MIS) 6 glacial period, a well-dated stalagmite (~194 to ~154 ka) from Kanaan Cave on the Mediterranean coast in Lebanon was analyzed for its petrography, growth history, and stable isotope geochemistry. A resolved climate record has been recovered from this precisely U–Th dated speleothem, spanning the late MIS 7 and early MIS 6 at low resolution and the mid–MIS 6 at higher resolution. The stalagmite grew discontinuously from ~194 to ~163 ka. More consistent growth and higher growth rates between ~163 and ~154 ka are most probably linked to increased water recharge and thus more humid conditions. More distinct layering in the upper part of the speleothem suggests strong seasonality from ~163 ka to ~154 ka. Short-term oxygen and carbon isotope excursions were found between ~155 and ~163 ka. The inferred Kanaan Cave humid intervals during the mid–MIS 6 follow variations of pollen records in the Mediterranean basins and correlate well with the synthetic Greenland record and East Asian summer monsoon interstadial periods, indicating short warm/wet periods similar to the Dansgaard-Oeschger events during MIS 4–3 in the eastern Mediterranean region. [ABSTRACT FROM AUTHOR]
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- 2018
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18. Climatic and in-cave influences on δ18O and δ13C in a stalagmite from northeastern India through the last deglaciation.
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Lechleitner, Franziska A., Breitenbach, Sebastian F.M., Cheng, Hai, Plessen, Birgit, Rehfeld, Kira, Goswami, Bedartha, Marwan, Norbert, Eroglu, Deniz, Adkins, Jess, and Haug, Gerald
- Abstract
Northeastern (NE) India experiences extraordinarily pronounced seasonal climate, governed by the Indian summer monsoon (ISM). The vulnerability of this region to floods and droughts calls for detailed and highly resolved paleoclimate reconstructions to assess the recurrence rate and driving factors of ISM changes. We use stable oxygen and carbon isotope ratios (δ18O and δ13C) from stalagmite MAW-6 from Mawmluh Cave to infer climate and environmental conditions in NE India over the last deglaciation (16–6ka). We interpret stalagmite δ18O as reflecting ISM strength, whereas δ13C appears to be driven by local hydroclimate conditions. Pronounced shifts in ISM strength over the deglaciation are apparent from the δ18O record, similarly to other records from monsoonal Asia. The ISM is weaker during the late glacial (LG) period and the Younger Dryas, and stronger during the Bølling-Allerød and Holocene. Local conditions inferred from the δ13C record appear to have changed less substantially over time, possibly related to the masking effect of changing precipitation seasonality. Time series analysis of the δ18O record reveals more chaotic conditions during the late glacial and higher predictability during the Holocene, likely related to the strengthening of the seasonal recurrence of the ISM with the onset of the Holocene. [ABSTRACT FROM PUBLISHER]
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- 2017
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19. Strong influence of water vapor source dynamics on stable isotopes in precipitation observed in Southern Meghalaya, NE India
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Breitenbach, Sebastian F.M., Adkins, Jess F., Meyer, Hanno, Marwan, Norbert, Kumar, Kanikicharla Krishna, and Haug, Gerald H.
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- 2010
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20. Temperature dependence of oxygen- and clumped isotope fractionation in carbonates: A study of travertines and tufas in the 6–95 °C temperature range.
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Kele, Sándor, Breitenbach, Sebastian F.M., Capezzuoli, Enrico, Meckler, A. Nele, Ziegler, Martin, Millan, Isabel M., Kluge, Tobias, Deák, József, Hanselmann, Kurt, John, Cédric M., Yan, Hao, Liu, Zaihua, and Bernasconi, Stefano M.
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OXYGEN isotopes , *THERMOMETRY , *THERMISTORS , *ISOTHERMAL processes , *ISOTOPIC fractionation - Abstract
Conventional carbonate–water oxygen isotope thermometry and the more recently developed clumped isotope thermometer have been widely used for the reconstruction of paleotemperatures from a variety of carbonate materials. In spite of a large number of studies, however, there are still large uncertainties in both δ 18 O- and Δ 47 -based temperature calibrations. For this reason there is a need to better understand the controls on isotope fractionation especially on natural carbonates. In this study we analyzed oxygen, carbon and clumped isotopes of a unique set of modern calcitic and aragonitic travertines, tufa and cave deposits from natural springs and wells. Together these samples cover a temperature range from 6 to 95 °C. Travertine samples were collected close to the vents of the springs and from pools, and tufa samples were collected from karstic creeks and a cave. The majority of our vent and pool travertines and tufa samples show a carbonate–water oxygen isotope fractionation comparable to the one of Tremaine et al. (2011) with some samples showing higher fractionations. No significant difference between the calcite–water and aragonite–water oxygen isotope fractionation could be observed. The Δ 47 data from the travertines show a strong relationship with temperature and define the regression Δ 47 = (0.044 ± 0.005 × 10 6 )/ T 2 + (0.205 ± 0.047). The pH of the parent solution, mineralogy and precipitation rate do not appear to significantly affect the Δ 47 -signature of carbonates, compared to the temperature effect and the analytical error. The tufa samples and three biogenic calcites show an excellent fit with the travertine calibration, indicating that this regression can be used for other carbonates as well. This work extends the calibration range of the clumped isotope thermometer to travertine and tufa deposits in the temperature range from 6 °C to 95 °C. [ABSTRACT FROM AUTHOR]
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- 2015
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21. Northeast Indian stalagmite records Pacific decadal climate change: Implications for moisture transport and drought in India.
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Myers, Christopher G., Oster, Jessica L., Sharp, Warren D., Bennartz, Ralf, Kelley, Neil P., Covey, Aaron K., and Breitenbach, Sebastian F.M.
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- 2015
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22. Closing in on the oxygen isotopic fractionation factor between calcite and water using natural carbonates.
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Breitenbach, Sebastian F.M., Hartland, Adam, Brall, Niels S., Sharp, Warren D., Sanchez, Fernando Gazquez, Rolfe, James, Bernasconi, Stefano M., and Hodell, David A.
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OXYGEN isotopes , *CALCITE , *ISOTOPIC fractionation , *CARBONATE minerals , *WATER use , *CARBONATES , *HOT springs , *EARTH (Planet) - Abstract
The oxygen isotopic fractionation between water and calcite is the cornerstone for estimating the formation temperature of calcite [1, 2, 3]. The oxygen isotope thermometer is one of the most valuable tools in geothermometry, palaeoclimatology and palaeoceanography. Despite 60 years of laboratory experiments and search for carbonate material precipitating at (near-)equilibrium [4, 5], establishing the temperature-dependent calcite-water fractionation factor has proven challenging. Here we address this problem with coupled traditional and clumped isotope measurements from an unconventional carbonate archive -- subaqueously-precipitated carbonates (SPC) which form in cave pools and drip sites, as well as natural hot springs. SPC include cave pearls, cave pool rim carbonates, hot spring pisoids, and carbonate geodes. Their common feature is subaqueous formation from supersaturated waters with an unlimited pool of calcium bicarbonate and very slow CO$_2$-degassing, which promote (near-)equilibrium conditions. Here, we expand on earlier work that used SPC as calibration material for clumped isotope thermometry [6] by measuring \delta$^{18}$O of 20 (sub-)modern SPC samples from caves and hot springs with known temperatures (0.8$^{\circ}$C and 76$^{\circ}$C) with calcite or aragonite mineralogies, together with their host water. Our results enable determination of the fractionation factor between carbonate and water for a wide temperature range. Additionally, clumped isotope measurements confirmed isotopic equilibrium for both, \delta$^{18}$O and \Delta$_{47}$ of the analysed SPCs, supporting the equilibrium equations of Coplen [4] and Watkins et al. [7]. SPC grown at thermodynamic equilibrium provide potential standard materials for temperature calibration of clumped isotopes.\textbf{References}\\1 McCrea J. M. (1950) On the isotopic chemistry of carbonates and a paleotemperatures scale. \textit{J. Chem. Phys.} 18, 163--171.\\2 Epstein S. et al. (1953) Revised carbonate-water isotopic temperature scale. \textit{Bull. Geol. Soc. Am.} 64, 1315--1326.\\3 Kim S.-T. and O'Neil J. R. (1997) Equilibrium and nonequilibrium oxygen isotope effects in synthetic carbonates. \textit{Geochim. Cosmochim. Acta} 61, 3461--3475.\\4 Coplen T.B. (2007) Calibration of the calcite--water oxygen-isotope geothermometer at Devils Hole, Nevada, a natural laboratory. \textit{Geochim. Cosmochim. Acta} 71, 3948--3957.\\5 Demeny A. et al. (2010) Empirical equations for the temperature dependence of calcite--water oxygen isotope fractionation from 10 to 70$^{\circ}$C. \textit{Rapid Commun. Mass Spectrom.} 24, 3521--3526.\\6 Breitenbach S.F.M. et al. (2018) Combining Mg/Ca and clumped isotopes in foraminifera for redundant estimation of temperature. \textit{Geochim. Cosmochim. Acta} 236, 283-296.\\7 Watkins et al. (2014) The influence of temperature, pH, and growth rate on the \delta$^{18}$O composition of inorganically precipitated calcite. \textit{Earth Planet. Sci. Lett.} 404, 332--343. [ABSTRACT FROM AUTHOR]
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- 2019
23. The Indian Summer Monsoon from a Speleothem \delta$^{18}$O Perspective -- A Review.
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Kaushal, Nikita, Breitenbach, Sebastian F.M., Lechleitner, Franziska A., Sinha, Ashish, Tewari, Vinod C., Ahmad, Syed M., Berkelhammer, Max, Band, Shraddha, Yadava, Madhusudan, Ramesh, Rengaswamy, and Henderson, Gideon M.
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OXYGEN isotopes , *ATMOSPHERIC circulation , *MONSOONS , *CARBONATE rocks , *CARBON isotopes , *STABLE isotope analysis - Abstract
As one of the most prominent seasonally recurring atmospheric circulation patterns, the Asian summer monsoon (ASM) plays a vital role for the life and livelihood of about one-third of the global population. Changes in the strength and seasonality of the ASM significantly affect the ASM region, yet the drivers of change and the varied regional responses of the ASM are not well understood. In the last two decades, there were a number of studies reconstructing the ASM using stalagmite-based proxies such as oxygen isotopes (\delta$^{18}$O). Such reconstructions allow examination of ASM drivers and responses, increasing monsoon predictability.In a review study [1], we focus on stalagmite \delta$^{18}$O records from India at the proximal end of the larger ASM region. Stalagmite-based time series are available from a number of caves in northern, northeastern and south Indian caves, as well as from the Andaman Islands. Despite widespread occurrence of carbonate rocks, data is lacking for Central and western India (the Vindhayans and Thar Desert), and Pakistan. We examine Indian stalagmite records collated in the Speleothem Isotope Synthesis and AnaLysis version 1 database [1] and support the database with a summary of record quality and regional climatic interpretations of the \delta$^{18}$O record during different climate states. Indian stalagmite \delta$^{18}$O records show well-dated, high-amplitude changes in response to the dominant drivers of the ASM on orbital to multi-centennial timescales, and indicate the magnitude of monsoon variability in response to these drivers.We suggest the most useful time periods (climatic events) and locations for further work using tools such as data-model comparisons, spectral analysis methods, multi-proxy investigations, and monitoring.References[1] Kaushal, N., Breitenbach, S.F.M., Lechleitner, F.A., Sinha, A., Tewari, V.C., Ahmad, S.M., Berkelhammer, M., Band, S., Yadava, M., Ramesh, R. and Henderson, G.M.: The Indian Summer Monsoon from a Speleothem $\delta^{18}$O Perspective -- A Review. Quaternary, 1, 29, https://doi.org/10.3390/quat1030029, 2018.\\[2] Atsawawaranunt, K., Comas-Bru, L., Amirnezhad Mozhdehi, S., Deininger, M., Harrison, S. P., Baker, A., Boyd, M., Kaushal, N., Ahmad, S. M., Ait Brahim, Y., Arienzo, M., Bajo, P., Braun, K., Burstyn, Y., Chawchai, S., Duan, W., Hatvani, I. G., Hu, J., Kern, Z., Labuhn, I., Lachniet, M., Lechleitner, F. A., Lorrey, A., P\'{e}rez-Mej\'{\i}as, C., Pickering, R., Scroxton, N., and SISAL Working Group Members: The SISAL database: a global resource to document oxygen and carbon isotope records from speleothems, Earth Syst. Sci. Data, 10, 1687-1713, https://doi.org/10.5194/essd-10-1687-2018, 2018. [ABSTRACT FROM AUTHOR]
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- 2019
24. Reducing Uncertainties in Carbonate Clumped Isotope Analysis Through Consistent Carbonate-Based Standardization
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Bernasconi, Stefano M., Müller, Inigo A., Bergmann, Kristin, Breitenbach, Sebastian F.M., Fernandez, Alvaro, Hodell, David A., Jaggi, Madalina, Meckler, Anna Nele, Millan, Isabel M., and Ziegler, Martin
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standardization ,carbonate ,13. Climate action ,paleothermometry ,clumped isotopes ,mass spectrometry - Abstract
About a decade after its introduction, the field of carbonate clumped isotope thermometry is rapidly expanding because of the large number of possible applications and its potential to solve long‐standing questions in Earth Sciences. Major factors limiting the application of this method are the very high analytical precision required for meaningful interpretations, the relatively complex sample preparation procedures, and the mass spectrometric corrections needed. In this paper we first briefly review the evolution of the analytical and standardization procedures and discuss the major remaining sources of uncertainty. We propose that the use of carbonate standards to project the results to the carbon dioxide equilibrium scale can improve interlaboratory data comparability and help to solve long‐standing discrepancies between laboratories and temperature calibrations. The use of carbonates reduces uncertainties related to gas preparation and cleaning procedures and ensures equal treatment of samples and standards. We present a set of carbonate standards of diverse composition, discuss how they can be used to correct for mass spectrometric biases, and demonstrate that their use significantly improves the comparability among four laboratories. We propose that the use of these standards or of a similar set of carbonate standards will improve the comparability of data across laboratories., Geochemistry, Geophysics, Geosystems, 19 (9), ISSN:1525-2027
25. The role of microorganisms in the formation of a stalactite in Botovskaya Cave, Siberia: Paleoenvironmental implications
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Pacton, Muriel, Breitenbach, Sebastian F.M., Lechleitner, Franziska A., Vaks, Anton, Rollion-Bard, Claire, Gutareva, O.S., Osintcev, A.V., and Vasconcelos, Crisogono
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13. Climate action - Abstract
Calcitic speleothems in caves can form through abiogenic or biogenic processes, or through a combination of both. Many issues conspire to make the assessment of biogenicity difficult, especially when focusing on old speleothem deposits. This study reports on a multiproxy analysis of a Siberian stalactite, combining high-resolution microscopy, isotope geochemistry and microbially enhanced mineral precipitation laboratory experiments. The contact between growth layers in a stalactite exhibits a biogenic isotopic signature; coupled with morphological evidence, this supports a microbial origin of calcite crystals. SIMS δ13C data suggest that microbially mediated speleothem formation occurred repeatedly at short intervals before abiotic precipitation took over. The studied stalactite also contains iron and manganese oxides that have been mediated by microbial activity through extracellular polymeric substance (EPS)-influenced organomineralization processes. The latter reflect paleoenvironmental changes that occurred more than 500 000 yr ago, possibly related to the presence of a peat bog above the cave at that time. Microbial activity can initiate calcite deposition in the aphotic zone of caves before inorganic precipitation of speleothem carbonates. This study highlights the importance of microbially induced fractionation that can result in large negative δ13C excursions. The microscale biogeochemical processes imply that microbial activity has only negligible effects on the bulk δ13C signature in speleothems, which is more strongly affected by CO2 degassing and the host rock signature., Biogeosciences, 10 (9), ISSN:1726-4170
26. COnstructing Proxy Records from Age models (COPRA)
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Breitenbach, Sebastian F.M., Rehfeld, Kira, Goswami, Bedartha, Baldini, James U.L., Ridley, Harriet E., Kennett, Douglas J., Prufer, Keith M., Aquino, Valorie V., Asmerom, Yemane, Polyak, Victor J., Cheng, Hai, Kurths, Jürgen, and Marwan, Norbert
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13. Climate action - Abstract
Reliable age models are fundamental for any palaeoclimate reconstruction. Available interpolation procedures between age control points are often inadequately reported, and very few translate age uncertainties to proxy uncertainties. Most available modeling algorithms do not allow incorporation of layer counted intervals to improve the confidence limits of the age model in question. We present a framework that allows detection and interactive handling of age reversals and hiatuses, depth-age modeling, and proxy-record reconstruction. Monte Carlo simulation and a translation procedure are used to assign a precise time scale to climate proxies and to translate dating uncertainties to uncertainties in the proxy values. The presented framework allows integration of incremental relative dating information to improve the final age model. The free software package COPRA1.0 facilitates easy interactive usage., Climate of the Past, 8 (5), ISSN:1814-9324, ISSN:1814-9332
27. Tropical rainfall over the last two millennia: Evidence for a low-latitude hydrologic seesaw
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Lechleitner, Franziska A., Breitenbach, Sebastian F.M., Rehfeld, Kira, Ridley, Harriet E., Asmerom, Yemane, Prufer, Keith M., Marwan, Norbert, Goswami, Bedartha, Kennett, Douglas J., Aquino, Valorie V., Polyak, Victor, Haug, Gerald H., Eglinton, Timothy I., and Baldini, James U.L.
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13. Climate action ,NORTH-ATLANTIC CLIMATE ,INTERTROPICAL CONVERGENCE ZONE ,COMMON ERA ,ICE-AGE ,VOLCANIC-ERUPTIONS ,PAST MILLENNIUM ,HIGH-RESOLUTION ,MONSOON RECORD ,VARIABILITY ,CAVE - Abstract
The presence of a low-to mid-latitude interhemispheric hydrologic seesaw is apparent over orbital and glacial-interglacial timescales, but its existence over the most recent past remains unclear. Here we investigate, based on climate proxy reconstructions from both hemispheres, the inter-hemispherical phasing of the Intertropical Convergence Zone (ITCZ) and the low-to mid-latitude teleconnections in the Northern Hemisphere over the past 2000 years. A clear feature is a persistent southward shift of the ITCZ during the Little Ice Age until the beginning of the 19th Century. Strong covariation between our new composite ITCZ-stack and North Atlantic Oscillation (NAO) records reveals a tight coupling between these two synoptic weather and climate phenomena over decadal-to-centennial timescales. This relationship becomes most apparent when comparing two precisely dated, high-resolution paleorainfall records from Belize and Scotland, indicating that the low-to mid-latitude teleconnection was also active over annual-decadal timescales. It is likely a combination of external forcing, i.e., solar and volcanic, and internal feedbacks, that drives the synchronous ITCZ and NAO shifts via energy flux perturbations in the tropics., Scientific Reports, 7, ISSN:2045-2322
28. Non-linear regime shifts in Holocene Asian monsoon variability: potential impacts on cultural change and migratory patterns
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Donges, Jonathan F., Donner, Reik V., Marwan, Norbert, Breitenbach, Sebastian F.M., Rehfeld, Kira, and Kurths, Jürgen
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13. Climate action ,15. Life on land - Abstract
The Asian monsoon system is an important tipping element in Earth's climate with a large impact on human societies in the past and present. In light of the potentially severe impacts of present and future anthropogenic climate change on Asian hydrology, it is vital to understand the forcing mechanisms of past climatic regime shifts in the Asian monsoon domain. Here we use novel recurrence network analysis techniques for detecting episodes with pronounced non-linear changes in Holocene Asian monsoon dynamics recorded in speleothems from caves distributed throughout the major branches of the Asian monsoon system. A newly developed multi-proxy methodology explicitly considers dating uncertainties with the COPRA (COnstructing Proxy Records from Age models) approach and allows for detection of continental-scale regime shifts in the complexity of monsoon dynamics. Several epochs are characterised by non-linear regime shifts in Asian monsoon variability, including the periods around 8.5–7.9, 5.7–5.0, 4.1–3.7, and 3.0–2.4 ka BP. The timing of these regime shifts is consistent with known episodes of Holocene rapid climate change (RCC) and high-latitude Bond events. Additionally, we observe a previously rarely reported non-linear regime shift around 7.3 ka BP, a timing that matches the typical 1.0–1.5 ky return intervals of Bond events. A detailed review of previously suggested links between Holocene climatic changes in the Asian monsoon domain and the archaeological record indicates that, in addition to previously considered longer-term changes in mean monsoon intensity and other climatic parameters, regime shifts in monsoon complexity might have played an important role as drivers of migration, pronounced cultural changes, and the collapse of ancient human societies., Climate of the Past, 11 (5), ISSN:1814-9324, ISSN:1814-9332
29. Holocene moisture changes in western China, Central Asia, inferred from stalagmites.
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Cai, Yanjun, Chiang, John C.H., Breitenbach, Sebastian F.M., Tan, Liangcheng, Cheng, Hai, Edwards, R. Lawrence, and An, Zhisheng
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STALACTITES & stalagmites , *MOISTURE , *HOLOCENE paleoclimatology , *CONVERGENCE (Meteorology) , *MONSOONS , *CLIMATE change - Abstract
Central Asia lies at the convergence between the Mediterranean and Asian monsoon climates, and there is a complex interaction between the westerlies with the monsoon to form the climate of that region and its variability. The region is highly vulnerable to changes in rainfall, highlighting the need to understand the underlying controls. We present a stalagmite-based δ 18 O record from Kesang Cave in western China, using MC-ICP-MS U-series dating and stable isotope analysis. Stalagmite calcite δ 18 O largely documents changes in the δ 18 O of precipitation. δ 18 O in stalagmites was low during the early and middle Holocene (10.0–3.0 ka BP), and shifted to higher values between 3.0 and 2.0 ka BP. After 2.0 ka BP, δ 18 O fluctuates with distinct centennial-scale variations. Drawing from results of state-of-the-art atmospheric general circulation model simulations for the preindustrial period and 9 ka BP, we propose that changes in moisture source regions and the wetter climate both contributed to the isotopic depletion of precipitation during the early and middle Holocene. Multiple records from surrounding regions indicate a generally wetter climate during the early and mid- Holocene, supporting our interpretation on the speleothem δ 18 O. Changes in precipitation seasonality do not appear to be a viable explanation for the observed changes, nor increased penetration of monsoonal moisture to the study site. We speculate that the climatic regime shifted around 3.0–2.0 ka BP towards a drier climate, resulting in temperature having dominant control on precipitation δ 18 O. The demise of three settlements around 500AD at the margin of Tarim Basin coincided with a period of decreased precipitation and increased temperature that likely affected local water resources, underscoring the potential impact of climate on human habitation in this region. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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30. Hydrological and climatological controls on radiocarbon concentrations in a tropical stalagmite.
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Lechleitner, Franziska A., Baldini, James U.L., Breitenbach, Sebastian F.M., Fohlmeister, Jens, McIntyre, Cameron, Goswami, Bedartha, Jamieson, Robert A., van der Voort, Tessa S., Prufer, Keith, Marwan, Norbert, Culleton, Brendan J., Kennett, Douglas J., Asmerom, Yemane, Polyak, Victor, and Eglinton, Timothy I.
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HYDROLOGIC cycle , *CARBON isotopes , *STALACTITES & stalagmites , *PALEOCLIMATOLOGY , *SEDIMENTATION & deposition , *KARST - Abstract
Precisely-dated stalagmites are increasingly important archives for the reconstruction of terrestrial paleoclimate at very high temporal resolution. In-depth understanding of local conditions at the cave site and of the processes driving stalagmite deposition is of paramount importance for interpreting proxy signals incorporated in stalagmite carbonate. Here we present a sub-decadally resolved dead carbon fraction (DCF) record for a stalagmite from Yok Balum Cave (southern Belize). The record is coupled to parallel stable carbon isotope (δ 13 C) and U/Ca measurements, as well as radiocarbon ( 14 C) measurements from soils overlying the cave system. Using a karst carbon cycle model we disentangle the importance of soil and karst processes on stalagmite DCF incorporation, revealing a dominant host rock dissolution control on total DCF. Covariation between DCF, δ 13 C, and U/Ca indicates that karst processes are a common driver of all three parameters, suggesting possible use of δ 13 C and trace element ratios to independently quantify DCF variability. A statistically significant multi-decadal lag of variable length exists between DCF and reconstructed solar activity, suggesting that solar activity influenced regional precipitation in Mesoamerica over the past 1500 years, but that the relationship was non-static. Although the precise nature of the observed lag is unclear, solar-induced changes in North Atlantic oceanic and atmospheric dynamics may play a role. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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31. Biomarkers record environmental changes along an altitudinal transect in the wettest place on Earth.
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Ernst, Nora, Peterse, Francien, Breitenbach, Sebastian F.M., Syiemlieh, Hiambok J., and Eglinton, Timothy I.
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BIOMARKERS , *CLIMATE change , *SOIL mapping , *GLYCERYL ethers , *PRECIPITATION (Chemistry) - Abstract
Highlights: [•] Analysis of plant wax δD and branched glycerol dialkyl glycerol tetraethers. [•] Area of research is a slope along the precipitation rich Meghalaya plateau, India. [•] We report an accurate representation of environmental changes by both proxies. [•] Plant wax δD agrees with measured stream water δD and modelled precipitation δD. [•] A revised calibration of the MBT/CBT proxy represents temperatures most accurately. [Copyright &y& Elsevier]
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- 2013
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32. Intra- and inter-annual uranium concentration variability in a Belizean stalagmite controlled by prior aragonite precipitation: A new tool for reconstructing hydro-climate using aragonitic speleothems.
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Jamieson, Robert A., Baldini, James U.L., Brett, Marianne J., Taylor, Jessica, Ridley, Harriet E., Ottley, Chris J., Prufer, Keith M., Wassenburg, Jasper A., Scholz, Denis, and Breitenbach, Sebastian F.M.
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ARAGONITE , *SPELEOTHEMS , *PALEOCLIMATOLOGY , *PRECIPITATION (Chemistry) , *URANIUM , *STALACTITES & stalagmites - Abstract
Aragonitic speleothems are increasingly utilised as palaeoclimate archives due to their amenability to high precision U–Th dating. Proxy records from fast-growing aragonitic stalagmites, precisely dated to annual timescales, can allow investigation of climatic events occurring on annual or even sub-annual timescales with minimal chronological uncertainty. However, the behaviour of many trace elements, such as uranium, in aragonitic speleothems has not thus far been as well constrained as in calcitic speleothems. Here, we use uranium concentration shifts measured across primary calcite-to-aragonite mineralogical transitions in speleothems to calculate the distribution coefficient of uranium in aragonitic speleothems (derived D U = 3.74 ± 1.13). Because our calculated D U is considerably above 1 increased prior aragonite precipitation due to increased karst water residence time should strongly control stalagmite aragonite U/Ca values. Consequently, uranium concentrations in aragonitic speleothems should act as excellent proxies for effective rainfall. We test this using a high-resolution ICP-MS derived trace element dataset from a Belizean stalagmite. YOK-G is an aragonitic stalagmite from Yok Balum cave in Belize with an extremely robust monthly-resolved chronology built using annual δ 13 C cycles. We interpret seasonal U/Ca variations in YOK-G as reflecting changes in the amount and seasonality of prior aragonite precipitation driven by variable rainfall amounts. The U/Ca record strongly suggests that modern drying has occurred in Belize, and that this drying was primarily caused by a reduction in wet season rainfall. This is consistent with published stable isotope data from YOK-G also very strongly suggesting modern rainfall reductions, previously interpreted as the result of southward ITCZ displacement. Our results strongly suggest that U/Ca values in aragonitic speleothems are excellent proxies for rainfall variability. This new tool, combined with the exceptional chronological control characteristic of aragonitic stalagmites and the high spatial resolution afforded by modern microanalytical techniques, should facilitate the construction of new exquisitely resolved rainfall records, providing rare insights into seasonality changes as well as long-term changes in local recharge conditions. [ABSTRACT FROM AUTHOR]
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- 2016
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33. Holocene variability of East Asian summer monsoon as viewed from the speleothem [formula omitted]O records in central China.
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Cai, Yanjun, Cheng, Xing, Ma, Le, Mao, Ruixue, Breitenbach, Sebastian F.M., Zhang, Haiwei, Xue, Gang, Cheng, Hai, Edwards, R. Lawrence, and An, Zhisheng
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SPELEOTHEMS , *STALACTITES & stalagmites , *HOLOCENE Epoch , *HILBERT-Huang transform , *MONSOONS , *CLIMATE change , *OCEAN temperature - Abstract
• A ∼4-yrs resolution Holocene stalagmite δ 18 O record from central China was studied. • The variability of 100-500- and 500-3000-yrs were diminished from 8.5 to 4.9 ka BP. • Changes in tropical SST likely caused the mid-Holocene weak monsoon events. • Climate change has impacts on the evolution of ancient cultures in central China. Monsoon precipitation in East China shows distinct spatial distribution and its variability is closely linked with the changes of the East Asian summer monsoon (EASM). Located in the transition zone between the southern subtropical humid climate and the northern warm temperate semi-humid climate, central China is a core region for recognizing and understanding the spatio-temporal variability of the EASM. Using U-series dating and stable isotope analysis on five stalagmites (MG-1, MG-2, MG-7, MG-40 and MG-64) from Magou Cave, Henan Province, Central China, we construct a high-resolution and precisely dated composite stalagmite δ 18 O time series covering most of the Holocene. This composite record reveals variations in precipitation δ 18 O between 11.7 and 1.1 ka BP with average resolution of ∼4 yrs. The Magou composite record demonstrates that EASM intensity dominates long-term changes in precipitation δ 18 O, which generally follows the northern hemisphere summer insolation (NHSI) trend. Both, Ensemble Empirical Mode Decomposition (EEMD) and wavelet filtering analyses real that the amplitudes of long-term (100-500 and 500-3000 yrs) components were slightly reduced between 8.5 and 4.9 ka BP, implying a weakened influence of climatic forcings on centennial and even millennial timescales during this warm period. Variance on 1-30-yr timescales is relatively low and ascribed to sampling resolution. Fourteen weak EASM intervals, including the 8.2 ka event, were identified within the period corresponding broadly with the Holocene Megathermal. Since no cold excursions other than the 8.2 ka event are found in the Greenland ice core records, we tentatively propose that oscillations in tropical sea surface temperature (SST) likely play an important role in steering other weak monsoon events. Aligning the Magou composite record and other moisture records with archaeological records from the study region, it seems that climate change influenced both the spatial distribution and agricultural practices of ancient cultures. However, overall moderate climatic changes in this region, most likely characterized by shifts between subtropical humid climate and warm temperate semi-humid climate, supported a generally consecutive development of ancient cultures without major hiatuses. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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