High-precision constraints on timing of Alpine warm periods during the middle to late Pleistocene using speleothem growth periods

Abstract

A long-standing problem in the reconstruction of warm climate periods during the late Quaternary is the difficulty of determining absolute ages for undisturbed terrestrial climate archives. Speleothems offer an important source of information about the timing and duration of middle and late Pleistocene warm phases. A flowstone from the high-elevation Spannagel Cave (Zillertal Alps, Austria) provides a new absolutely dated climate record, which includes the most prominent warm phases between ∼260 and 50 ka before present. New data from the Penultimate Interglacial improve our knowledge about the timing and progression of warm periods in the Alps corresponding to marine isotope stages 7 and 8. Speleothem growth phases were identified from ∼261 to 249, from ∼236 to 229, and from ∼200 to 192 ka. An early onset of the Last Interglacial is corroborated by a growth phase commencing at 136.7 ± 2.8 ka and the youngest section of the flowstone provides further evidence for an Alpine climate during time intervals corresponding to marine isotope stages 5a and 3 sufficiently warm to allow speleothems to grow. The high-resolution stable isotope profile taken along the growth axis of the flowstone provides information about the hydrological conditions during the growth phases.