Evidence of warm and humid interstadials in central Europe during early MIS 3 revealed by a multi-proxy speleothem record

Abstract

Marine Isotope Stage 3 (MIS 3,-27 ka) was characterised by numerous rapid climate oscillations (i.e., Dansgaard-Oeschger (D/O-) events), which are reflected in various climate archives. So far, MIS 3 speleothem records from central Europe have mainly been restricted to caves located beneath temperate Alpine glaciers or close to the Atlantic Ocean. Thus, MIS 3 seemed to be too cold and dry to enable speleothem growth north of the Alps in central Europe. Here we present a new speleothem record from Bunker Cave, Germany, which shows two distinct growth phases from 52.0 (+0.8,-0.5) to 50.9 (+0.6,-1.3) ka and 47.3 (+1.0,-0.6) to 42.8 (± 0.9) ka, rejecting this hypothesis. These two growth phases potentially correspond to the two warmest and most humid phases in central Europe during MIS 3, which is confirmed by pollen data from the nearby Eifel. The hiatus separating the two phases is associated with Heinrich stadial 5 (HS 5), although the growth stop precedes the onset of HS 5. The first growth phase is characterised by a fast growth rate, and Mg concentrations and Sr isotope data suggest high infiltration and the presence of soil cover above the cave. The second growth phase was characterised by drier, but still favourable conditions for speleothem growth. During this phase, the δ 13 C values show a significant decrease associated with D/O-event 12. The timing of this shift is in agreement with other MIS 3 speleothem data from Europe and Greenland ice core data.

NanoSr – A New Carbonate Microanalytical Reference Material for In Situ Strontium Isotope Analysis

“…As shown in Figure 1e, the pore space of the pressed nanopowder pellet is < 1 µm, indicating a well-compacted material, which is a prerequisite for microhomogeneity. In addition, the Ca mass fraction is in good agreement with Ca mass fractions commonly used for LA-ICP-MS trace element determinations in carbonates, where Ca is used as an internal reference (e.g., Jochum et al 2005, Mischel et al 2017, Weber et al 2018b), although it is slightly lower than expected from the stoichiometric value CaO for calcium carbonate of 56.03% m/m. For the use as a Sr isotope reference material, the precise knowledge of the Ca mass fraction is not relevant for calibration purposes.…”

“…This shows the need of carbonate microanalytical RMs with a relatively low‐Sr mass fraction for in situ Sr isotope analysis of low‐Sr, low‐REE carbonates, such as speleothems. For this type of carbonates, the application of LA‐MC‐ICP‐MS is currently restricted either to high‐Sr samples (Weber et al , Wortham et al ) or to solution‐based analysis, which requires chemical separation prior to analysis (Banner et al , Goede et al , Zhou et al , Hori et al , Oster et al , Weber et al ).…”

Global aridity synthesis for the last 60 000 years

“…The dust index (Dietrich and Seelos, 2010;Dietrich and Sirocko, 2011;Seelos et al, 2009) reveals the GIs in details. The closest known and well dated speleothems to the Eifel region are from the Bunker Cave in Sauerland (Fohlmeister et al, 2012;Weber et al, 2018) which can be compared to the Spannagel Cave system from western Zillertal, Austria (Holzkämper et al, 2004).…”

“…We start the synthesis with our own dust and pollen records from Eifel (Seelos et al, 2009;Sirocko et al, 2016), which we compare with speleothem data from nearby Bunker Cave (Fohlmeister et al, 2012(Fohlmeister et al, , 2013Weber et al, 2018) as well as the Spannagel Cave in Austria (Holzkämper et al, 2004;Spötl and Mangini, 2002). The maar sediment cores of the Eifel Laminated Sediment Archive (ELSA)-project (Sirocko, 2016;Sirocko et al, 2016) show all Greenland Stadials (GS) and…”

Nano‐Powdered Calcium Carbonate Reference Materials: Significant Progress for Microanalysis?

“…Laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) has become a suitable technique for microanalysis of these materials (e.g., Wassenburg et al , Jochum et al , Jentzen et al , Leduc et al , Yang et al , Mertz‐Kraus et al , Hathorne et al . , Vetter et al , Caragnano et al , Schiebel and Hemleben , Weber et al ), but well‐characterised homogeneous reference materials (RMs) for calibration at the nanometre to micrometre scale are needed. For such purposes, different kinds of RMs were used, for example, the silicate glasses from the National Institute of Standards and Technology (NIST), geological glasses from the United States Geological Survey (USGS), the Max Planck Institute for Chemistry (MPI‐DING) and synthetic or natural carbonates (USGS) (Jochum and Enzweiler ).…”