EGU21-9159
https://doi.org/10.5194/egusphere-egu21-9159
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Palaeohydrologic interpretations of Holocene wet episodes recorded in stalagmites from Soreq Cave, Israel: Linking the magnetic and isotopic properties of speleothems

Yuval Burstyn1, Ron Shaar1, Jonathan Keinan1, Yael Ebert1, Avner Ayalon2, Miryam Bar-Matthews2, and Joshua M. Feinberg3
Yuval Burstyn et al.
  • 1The Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel (yuval.burstyn@mail.huji.ac.il)
  • 2Geological Survey of Israel, 32 Yesha'ayahu Leibowitz Street, Jerusalem, 9692100, Israel
  • 3Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN 55455, USA

Soil-derived magnetic particles trapped in speleothems can retain valuable information on the physiochemical conditions of the overlying soil and changes in the hydrological system. However, a direct link between magnetic and isotopic properties of speleothems has been only qualitatively established and is known to vary regionally. Here we investigate two Holocene speleothems from Soreq Cave, Israel and provide evidence for strong coupling over centennial to millennial timescales between the inflow of magnetic particles (quantified using the magnetic flux index, IRMflux), δ13C, and rainfall amounts. The two stalagmites formed at separate intervals: one at ~9.5 ky BP capturing the transition from pluvial Eastern Mediterranean conditions associated with Sapropel 1 (S1) and a second at 5.4 ky BP recording mid-Holocene wet-dry cycles.

The late-Holocene speleothem shows an anomalously high δ13C episode that is correlated with extremely low IRMflux, indicating minimal contribution from overlying soils due to either (1) recently denuded soils, or (2) high overland and vadose runoff. By contrast, the mid-Holocene sample shows saw-tooth cycles in both δ18O and δ13C, which are interpreted as rapid climate fluctuations associated with rainfall changes. IRMflux during this period varies in-phase with the δ13C cycles; however, the peaks in IRMflux values precede those of the isotope values. The apparent lag in isotopic values may be explained by the faster response of the IRMflux to increased rainfall resulting from the rapid physical translocation of overlying soil particles via groundwater, compared with slower soil organic matter turnover rates, which may vary on timescales of up to thousands of years.

The separate palaeohydrological scenarios resolved from the two speleothems demonstrate how magnetic data can act as a powerful paleo-hydrology proxy, even in weakly-magnetized speleothems growing under semi-arid conditions.

How to cite: Burstyn, Y., Shaar, R., Keinan, J., Ebert, Y., Ayalon, A., Bar-Matthews, M., and Feinberg, J. M.: Palaeohydrologic interpretations of Holocene wet episodes recorded in stalagmites from Soreq Cave, Israel: Linking the magnetic and isotopic properties of speleothems, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9159, https://doi.org/10.5194/egusphere-egu21-9159, 2021.

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