Lead isotope variability in speleothems—A promising new proxy for hydrological change? First results from a stalagmite from western Germany Qichao Yang a, ⁎, Denis Scholz a,b , Klaus Peter Jochum a , Dirk L. Hoffmann c,d , Brigitte Stoll a , Ulrike Weis a , Beate Schwager a , Meinrat O. Andreae a a Biogeochemistry Department, Max Planck Institute for Chemistry, P.O. Box 3060, 55020 Mainz, Germany b Institut für Geowissenschaften, Johannes-Gutenberg-Universität, Johann-Joachim-Becher-Weg 21, 55128 Mainz, Germany c Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany d Bristol Isotope Group (BIG), School of Geographical Sciences, University of Bristol, University Road, BS8 1SS Bristol, United Kingdom abstract article info Article history: Received 26 April 2014 Received in revised form 19 December 2014 Accepted 30 December 2014 Available online 7 January 2015 Editor: David R. Hilton Keywords: Stalagmite Lead isotope Trace element Hydrology We studied an aragonitic section of ca. 6 cm length of stalagmite HBSH-1 from the Hüttenbläserschachthöhle, western Germany. 230 Th/U-dating revealed that this section grew between ~210 and ~190 ka, with a relatively uniform growth rate of 3.1 μma -1 . For the first time, we determined Pb isotope ratios ( 207 Pb/ 206 Pb and 208 Pb/ 206 Pb) in a stalagmite by laser ablation (LA)-ICP-MS. In addition, we analyzed various trace element (Mg, Al, Si, P, Mn, Sr, Pb and Th) concentrations. The results indicate that Pb in HBSH-1 originated from two external sources: (i) the regional galena (PbS) min- eralization with high Pb content as well as isotope ratios, and (ii) the carbonate fraction in the host rock with low Pb content as well as isotope ratios. Except for Sr, all trace elements show similar variations, probably driven by the amount of infiltration into the cave system. This is probably the result of the similar transport and incorpora- tion mechanisms of these elements as colloids and/or particles. The Pb isotope ratios also show a strong correla- tion with trace element variability strongly suggesting that the Pb isotope variability in HBSH-1 has the potential to be used as a promising new proxy for hydrological change. Based on the observed variability, we identify two phases (from ~204.9 to ~201.5 and from ~198.4 to ~195.9 ka) with enhanced water infiltration in the cave region. Between ~210.0 and ~204.9, ~201.5 and ~198.4 as well as ~195.9 and ~190.0 ka less infiltration occurred. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Speleothems, such as stalagmites and flowstones, have been widely used as paleoclimate archives (e.g., McMillan et al., 2005; Spötl et al., 2008; Wang et al., 2008; Wassenburg et al., 2012). They often have long continuous growth periods that can be dated precisely and accu- rately by U-series methods (Scholz and Hoffmann, 2008), and provide multiple paleoenvironmental proxies that can be analyzed at high reso- lution (Fairchild et al., 2006). Moreover, the occurrence of speleothems in all continental areas overlain by limestone or dolomite provides the opportunity for comparison of past climate changes in different regions (Henderson, 2006). The most commonly measured proxies in speleothems are carbon and oxygen isotope ratios (δ 13 C and δ 18 O), which have been utilized to reconstruct soil/vegetation dynamics (e.g., Genty et al., 2003) and temperature/precipitation changes (McDermott, 2004), respectively. Recently, speleothem trace element records have received increased attention for reconstruction of paleohydrological processes (Treble et al., 2003; Fairchild et al., 2006; Borsato et al., 2007; Fairchild and Treble, 2009; Hartland et al., 2012; Wassenburg et al., 2012, 2013). Isotope ratios, such as 87 Sr/ 86 Sr, 234 U/ 238 U and δ 34 S, provide the potential to record atmospheric fluxes or local hydrological conditions (Goede et al., 1998; Zhou et al., 2005; Wynn et al., 2008). Finally, analysis of fluorescent organic material in speleothems enabled the recognition of flushing events of the cave systems since the mobilization of organic matter from the overlying soil may be triggered by rainfall intensity (Baker et al., 2002; Borsato et al., 2007). High organic content in speleothems often coincides with elevated content of certain trace metals, such as Y, Zn, Cu, Pb, Ni, Co, Ti and V, which show varying binding affinity with organic matter in dif- ferent size ranges (i.e., dissolved, colloidal and/or particulate) in cave waters (Borsato et al., 2007; Hartland et al., 2012). Furthermore, P is released from plant residues during decay of vegetation and transported into the cave system by enhanced water infiltration. Consequently, speleothem P has been observed to accumulate in organic-rich layers Chemical Geology 396 (2015) 143–151 ⁎ Corresponding author. Tel.: +49 61 313056705. E-mail address: qichao.yang@mpic.de (Q. Yang). http://dx.doi.org/10.1016/j.chemgeo.2014.12.028 0009-2541/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Chemical Geology journal homepage: www.elsevier.com/locate/chemgeo