Stalagmite-inferred European westerly drift in the early Weichselian with centennial-scale variability in marine isotope stage 5a

https://doi.org/10.1016/j.quascirev.2022.107581Get rights and content

Highlights

  • Stalagmite δ18O and δ13C records from Monaco show precipitation changes in southern Europe from 89 to 80 ka at MIS 5b-5a.

  • Multi-centennial arid events at 84-80 ka during MIS 5a could be linked to AMOC slowdowns, NAO states, and solar activity.

  • Models suggest that centennial-scale AMOC slowdowns at MIS 5a could induce reduced precipitation over western Europe.

Abstract

The Weichselian glaciation is characterized by significant ocean circulation variations starting from ∼115 thousand years ago (ka) and terminating at ∼11.5 ka. The early Weichselian (115–74 ka), especially marine isotope stage (MIS) 5a at 85–74 ka, provides a window for understanding the linkage between the European westerlies and Mediterranean climate. However, lack of highly-resolved paleoclimate records with absolute chronologies hampers our knowledge of decadal-to-centennial-scale climate changes and forcings in the circum-Mediterranean realm. Here, we present 230Th-dated stalagmite-inferred hydroclimate records from Observatoire cave (43°44′ N, 7°25’ E), Monaco, for the period between 88.7 ± 0.4 and 80.3 ± 0.1 ka, covering portions of MIS 5b and 5a. Agreement between Observatoire and circum-Mediterranean stalagmite records confirm large-scale warming over the Atlantic-Europe territory during the transition from MIS 5b to 5a. Subdecadally-resolved Observatoire δ18O and δ13C records express four multi-centennial arid intervals in southern Europe at 84–80 ka in the first-half of MIS 5a, suggesting centennial westerly drifts, a finding supported by a model simulation. Westerly changes and associated arid events can be attributed to slowdowns of the Atlantic meridional overturning circulation, North Atlantic Oscillation states, and solar activity.

Introduction

The last glacial cycle, starting from marine isotope stage (MIS) 5e at ∼130 thousand years ago (ka, relative to AD 1950; hereafter), features rapid and recurrent millennial climate variations, as documented in Greenland ice cores with relatively warm interstadials (GI) and cold stadials (GS) (Johnsen et al., 1992; Dansgaard et al., 1993; NorthGRIP-Members, 2004) (Fig. 1a). Northern hemisphere summer insolation (NHSI) peaks (Fig. 1b) brought warm temperatures and ice volume reductions, interrupting the Earth's transition from the last interglacial to last glacial maximum (Lambeck and Chappell, 2001). In the early Weichselian (∼115–74 ka), two warm intervals, MIS 5c and 5a (Fig. 1) started following the NHSI maximum at 105 and 85 ka (Fig. 1b), with the global sea-level maximum reaching −10 to −20 m at 100 and 83 ka, respectively (Fig. 1e). These two warm intervals featured unstable ice-sheet configurations in Fennoscandia, Greenland, and North America (Chapman and Shackleton, 1999; Mokeddem and McManus, 2016; Batchelor et al., 2019). Ice-sheet instability and the associated meltwater input in the North Atlantic may have resulted in multi-centennial to millennial oscillations in Asian stalagmite δ18O values associated with Asian monsoon intensity variations (Cheng et al., 2016) (Fig. 1b). Fluctuations in Atlantic planktic foraminiferal δ18O (δ18Opf) values (Fig. 1c; de Abreu et al., 2003) and sea surface temperatures (SST) off the Iberian margin (Fig. 1c; Martrat et al., 2004) during MIS 5c and 5a also suggest variations in the Atlantic meridional overturning circulation (AMOC), which can modulate the hydroclimate of the North Atlantic and Europe (Stouffer et al., 2006; Margari et al., 2010; Kageyama et al., 2013; Jackson et al., 2015; Stockhecke et al., 2016; Tzedakis et al., 2018). For example, abrupt δ18O shifts in Alpine stalagmite records (NALPS; Fig. 1d) which correspond to the δ18O shifts in Greenland ice cores (Fig. 1a; NorthGRIP-Members, 2004) could have been affected by ocean circulation changes (Boch et al., 2011). At the end of MIS 5b (∼85 ka), the abrupt positive shift in NALPS δ18O has been linked to the end of GS22, accompanying warming in the North Atlantic (Boch et al., 2011).

The circum-Mediterranean region has a classical Mediterranean climate featuring hot/dry summers and mild/wet winters (Beck et al., 2018). Over the past two decades, droughts in southern Europe have threatened water supply, ecosystem, and agricultural instabilities over the past two decades (Hoerling et al., 2012; Naumann et al., 2021). Complex forcings from rising greenhouse gases, ice-sheet meltwater input, and changes in the strength of AMOC hinder our ability to reliably predict Mediterranean hydroclimate over the next century. As NHSI values during MIS 5a are as high as those in the Holocene (Berger, 1978; Laskar et al., 2011), highly-resolved proxy records during MIS 5a offer important clues to better understand the future climate. Previous studies have highlighted centennial-to-millennial scale climatic variability in the North Atlantic during MIS 5 (e.g., Oppo et al., 1997; Mokeddem and McManus, 2016), especially in southern Europe (Denniston et al., 2018; Tzedakis et al., 2018; Budsky et al., 2019). Most cases, however, have focused on the Eemian warm period (MIS 5e; e.g., Tzedakis et al., 2003, 2018; Drysdale et al., 2005; Allen and Huntley, 2009; Milner et al., 2013;). Less attention has been given to subcentennial-to centennial-scale variability during MIS 5a due to the limitation of archive resolution and dating precision.

Here, we present a subdecadal-to multidecadal-resolved stalagmite-inferred precipitation record with robust chronology, from Monaco (northern Mediterranean) to understand hydroclimate variability associated with the westerly changes during 88.7–80.3 ka in the early Weichselian, especially focusing on MIS 5a. This is complemented by results from a transient experiment for the period 86–80 ka performed with the Earth system model (LOVECLIM), to assess the potential hydroclimatic variability drivers in southern Europe.

Section snippets

Cave and regional settings

Observatoire cave ([43°43′ N, 7°24’ E], 103 m above sea level) (Fig. 2, Fig. 3) preserves evidence of the oldest human occupations in Monaco, southern Europe (Rossoni-Notter et al., 2016). The cave is located along the northwestern Mediterranean coastline, in upper Jurassic bedrock - a limestone block from the “Arc de Nice” subalpine mountain chain (Gilli, 1999). This 600 m-long cave opens to the south and its entrance hall is 17 m in length, 6 m in width, and 7 m in height (Fig. 3a). After the

U–Th data and age model

Detailed U–Th isotopic and concentration data and dating results of Observatoire stalagmites OV12-1 and 12-5 are given in Table S1. Stalagmite OV12-1 has 238U content of 0.4–0.7 × 10−6 g/g and 232Th context of 10–2200 × 10−9 g/g. Stalagmite OV12-5 features high 238U contents of 1.5–8.5 × 10−6 g/g and low 232Th contents of 0.01–2.1 × 10−9 g/g. The uncertainties of corrected 230Th dates are from ± 368 to ± 597 years on OV12-1 and from ± 19 to ± 180 years on OV12-5. The dates are in stratigraphic

Tests for stalagmite isotopic equilibrium conditions

Factors affecting isotopic compositions in stalagmites depend on a variety of isotopic fractionation processes during rainfall condensation and water infiltration in karst systems (McDermott, 2004). Unexpected kinetic effects that are usually associated with degassing during carbonate precipitation could bias the isotope signals from the climatic imprint. The Hendy test (Hendy, 1971) and duplication test (Dorale and Liu, 2009) have been widely used for evaluating isotopic equilibrium. The

Conclusions

We present stalagmite δ18O and δ13C-inferred precipitation records from 88.7 ± 0.4 to 80.3 ± 0.1 ka covering parts of MIS 5b to 5a from Observatoire cave, Monaco, southern Europe. The inferred precipitation record features four multi-centennial arid events during MIS 5a, suggesting that the westerlies moved away from Monaco. New transient simulation suggests that AMOC slowdowns can divert the westerlies from the Mediterranean region, which would result in stalagmite-inferred dry conditions in

Author contributions

C.-C.S. directed this research. C.-C.S., Y.-C.C. and H.-M.H conceived the project. C.-C.S., V.M., P.V., P.S., E.R.-N., A.M. and C.-C.W. conducted field surveys and collected stalagmites. Y.-C.C. and H.-M.H. conducted subsample preparation. Y.-C.C. and H.-M.H performed U–Th dating. H.-S.M. and X.J. conducted carbon and oxygen stable isotope analyses. L.M. conducted model simulations. A.M. conducted statistical analyses. Y.-C.C., C.-C.S., H.-M.H., L.M., and H.S. prepared the draft and

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

We would like to deeply thank G.S. Burr of the Research Center for Future Earth, National Taiwan University, for his constructive suggestions. We are thankful for the financial support provided by grants from the Science Vanguard Research Program of the Ministry of Science and Technology, Taiwan, ROC (110-2123-M-002-009), the Higher Education Sprout Project of the Ministry of Education, Taiwan, ROC (110L901001 and 110L8907), and the National Taiwan University (109L8926). We are also grateful

References (107)

  • C.C. Day et al.

    Controls on trace-element partitioning in cave-analogue calcite

    Geochem. Cosmochim. Acta

    (2013)
  • L. de Abreu et al.

    Millennial-scale oceanic climate variability off the Western Iberian margin during the last two glacial periods

    Mar. Geol.

    (2003)
  • O.A. Dumitru et al.

    Climate variability in the western Mediterranean between 121 and 67 ka derived from a Mallorcan speleothem record

    Palaeogeogr. Palaeoclimatol. Palaeoecol.

    (2018)
  • I.J. Fairchild et al.

    Controls on trace element (Sr–Mg) compositions of carbonate cave waters: implications for speleothem climatic records

    Chem. Geol.

    (2000)
  • I.J. Fairchild et al.

    Modification and preservation of environmental signals in speleothems

    Earth Sci. Rev.

    (2006)
  • J. Fohlmeister

    A statistical approach to construct composite climate records of dated archives

    Quat. Geochronol.

    (2012)
  • J. Fohlmeister et al.

    Carbon and oxygen isotope fractionation in the water-calcite-aragonite system

    Geochem. Cosmochim. Acta

    (2018)
  • S. Frisia et al.

    Late Holocene annual growth in three Alpine stalagmites records the influence of solar activity and the North Atlantic Oscillation on winter climate

    Earth Planet Sci. Lett.

    (2003)
  • J.M. García-Ruiz et al.

    Mediterranean water resources in a global change scenario

    Earth Sci. Rev.

    (2011)
  • E. Gilli

    Evidence of palaeoseismicity in a flowstone of the observatoire cave (Monaco)

    Geodin. Acta

    (1999)
  • C.H. Hendy

    The isotopic geochemistry of speleothems-I. The calculation of the effects of different modes of formation on the isotopic composition of speleothems and their applicability as palaeoclimatic indicators

    Geochem. Cosmochim. Acta

    (1971)
  • L. Heusser et al.

    Millennial- and orbital-scale climate variability in southeastern United States and in the subtropical Atlantic during Marine Isotope Stage 5: evidence from pollen and isotopes in ODP Site 1059

    Earth Planet Sci. Lett.

    (2003)
  • M.S. Lachniet

    Climatic and environmental controls on speleothem oxygen-isotope values

    Quat. Sci. Rev.

    (2009)
  • A. Mangini et al.

    Reconstruction of temperature in the central Alps during the past 2000 yr from a δ18O stalagmite record

    Earth Planet Sci. Lett.

    (2005)
  • F. McDermott

    Palaeo-climate reconstruction from stable isotope variations in speleothems: a review

    Quat. Sci. Rev.

    (2004)
  • A. Morley et al.

    Ocean-atmosphere climate shift during the mid-to-late Holocene transition

    Earth Planet Sci. Lett.

    (2014)
  • E.J. Rohling et al.

    Mediterranean climate and oceanography, and the periodic development of anoxic events (sapropels)

    Earth Sci. Rev.

    (2015)
  • C.S. Romanek et al.

    Carbon isotopic fractionation in synthetic aragonite and calcite: effects of temperature and precipitation rate

    Geochem. Cosmochim. Acta

    (1992)
  • E. Rossoni-Notter et al.

    Acheulean in Monaco: observatoire cave and its singular occupations

    Quat. Int.

    (2016)
  • M.F. Sánchez Goñi et al.

    High resolution palynological record off the Iberian margin: direct land-sea correlation for the last interglacial complex

    Earth Planet Sci. Lett.

    (1999)
  • D. Scholz et al.

    StalAge - an algorithm designed for construction of speleothem age models

    Quat. Geochronol.

    (2011)
  • M. Schulz et al.

    REDFIT: estimating red-noise spectra directly from unevenly spaced paleoclimatic time series

    Comput. Geosci.

    (2002)
  • C.-C. Shen et al.

    Variation of initial 230Th/232Th and limits of high precision U-Th dating of shallow-water corals

    Geochem. Cosmochim. Acta

    (2008)
  • C.-C. Shen et al.

    High-precision and high-resolution carbonate 230Th dating by MC-ICP-MS with SEM protocols

    Geochem. Cosmochim. Acta

    (2012)
  • R. Sprovieri et al.

    Suborbital climate variability during Marine Isotopic Stage 5 in the central Mediterranean basin: evidence from calcareous plankton record

    Quat. Sci. Rev.

    (2006)
  • M. Stockhecke et al.

    Millennial to orbital-scale variations of drought intensity in the Eastern Mediterranean

    Quat. Sci. Rev.

    (2016)
  • D.L. Thatcher et al.

    Linking the karst record to atmospheric, precipitation, and vegetation dynamics in Portugal

    Chem. Geol.

    (2020)
  • P.C. Tzedakis et al.

    Last Interglacial conditions in southern Europe: evidence from Ioannina, northwest Greece

    Global Planet. Change

    (2003)
  • A. Abe-Ouchi et al.

    Climatic conditions for modelling the Northern Hemisphere ice sheets throughout the ice age cycle

    Clim. Past

    (2007)
  • Y. Ait Brahim et al.

    North Atlantic ice-rafting, ocean and atmospheric circulation during the Holocene: insights from western Mediterranean speleothems

    Geophys. Res. Lett.

    (2019)
  • Y. Ait Brahim et al.

    Multi-decadal to centennial hydro-climate variability and linkage to solar forcing in the Western Mediterranean during the last 1000 years

    Sci. Rep.

    (2018)
  • M. Bar-Matthews et al.

    Mid-Holocene climate variations revealed by high-resolution speleothem records from Soreq Cave, Israel and their correlation with cultural changes

    Holocene

    (2011)
  • C.L. Batchelor et al.

    The configuration of Northern Hemisphere ice sheets through the Quaternary

    Nat. Commun.

    (2019)
  • H.E. Beck et al.

    Present and future köppen-geiger climate classification maps at 1-km resolution

    Sci. Rep.

    (2018)
  • R. Boch et al.

    NALPS: a precisely dated European climate record 120-60 ka

    Clim. Past

    (2011)
  • G. Bond et al.

    Persistent solar influence on North Atlantic climate during the Holocene

    Science

    (2001)
  • A. Budsky et al.

    Western Mediterranean climate response to Dansgaard/Oeschger events: new insights from speleothem records

    Geophys. Res. Lett.

    (2019)
  • H. Celle-Jeanton et al.

    Isotopic typology of the precipitation in the Western Mediterranean region at the three different time scales

    Geophys. Res. Lett.

    (2001)
  • M.R. Chapman et al.

    Global ice-volume fluctuations, North Atlantic ice-rafting events, and deep-ocean circulation changes between 130 and 70 ka

    Geology

    (1999)
  • H. Cheng et al.

    The Asian monsoon over the past 640,000 years and ice age terminations

    Nature

    (2016)
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