Timing and duration of Termination IV using stable isotope records of four stalagmites from Dechencave (western Germany)

Four stalagmites were sampled from different excavations in Dechencave (western Germany) and dated to Marine Isotope Stage (MIS) 9. MIS 9 is a very interesting interglacial due to its comparatively high concentration of greenhouse gasses (Lang & Wolff, 2011) and high temperatures (Petit et al., 1999), which are on the same level as during early industrial times (Robertson et al., 2001). Speleothem records from this time period are rare, in particular from central Europe. The stalagmites were precisely dated by the ²³⁰Th/U-method using MC-ICP-MS (Mainz University) and stable carbon and oxygen isotope composition were measured using CF-IRMS (Mainz University).

The stalagmites grew from 343 to 326 ka BP including Termination IV and MIS 9e. The stable oxygen isotope records of the four stalagmites show rapidly increasing values reflecting the temperature increase during the termination. The timing of this increase agrees well with the timing of Termination IV in the LR04 benthic foraminifera stack (Lisiecki & Raymo, 2005). However, the duration of the termination is shorter in the stalagmites than in the LR04 benthic foraminifera stack (Lisiecki & Raymo, 2005). The stable carbon isotope data decrease, but later and more gradually than the stable oxygen isotope data. This indicates a delayed and more gradual response of the evolving vegetation in response to the warming during Termination IV.

 

 

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