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A.Moreno (1,2), H. Stoll (3), I. Cacho (4), Montserrat Jiménez- Sánchez (3), Carlos Sancho (5), Ánchel Belmonte (5), R. L. Edwards (1), E. Ito (1), B.

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Presentation on theme: "A.Moreno (1,2), H. Stoll (3), I. Cacho (4), Montserrat Jiménez- Sánchez (3), Carlos Sancho (5), Ánchel Belmonte (5), R. L. Edwards (1), E. Ito (1), B."— Presentation transcript:

1 A.Moreno (1,2), H. Stoll (3), I. Cacho (4), Montserrat Jiménez- Sánchez (3), Carlos Sancho (5), Ánchel Belmonte (5), R. L. Edwards (1), E. Ito (1), B. L. Valero-Garcés (2) (1) Limnological Research Center, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN (USA) (2) Pyrenean Institute of Ecology - CSIC, Apdo. 202, Zaragoza, (Spain), (3) Departamento de Geologia, Universidad de Oviedo, C/ Arias de Velasco, s/n Oviedo (Spain), (4) University of Barcelona, C/ Marti i Franquès s/nº, Barcelona (Spain), (5) Departamento de Ciencias de la Tierra, Facultad de Ciencias. Universidad de Zaragoza (Spain), Paleoclimate reconstruction from northern Iberian Peninsula: the speleothem record

2 Outline Speleothems as exceptional paleoclimate archives Orbital scale Last deglaciation main trends Early Holocene abrupt changes Study sites in the north of the Iberian Peninsula Main questions Conclusions A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula Some preliminary results…

3 Speleothems as exceptional paleoclimate archives A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula Advantages - Absolute dating by using the U-Th desintegration series (0-500 kyrs) - High precipitation rate (banding) –abrupt/rapid climate changes - Good records of temperature and precipitation (stable isotopes, trace metals, growth rates…) Disadvantages - Only in karstic systems - System monitoring is required (lot of time and money….) - Presence of hiatus in dry or cold climates

4 Fairchild et al., 2006 Speleothems as exceptional paleoclimate archives A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula

5 Speleothems as exceptional paleoclimate archives A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula 2 initial assumptions: - Closed system to U and Th - Initial 230 Th = 0 (“pure” samples, with low detrital) Some sources of errors: - Low U content (depends on the type of limestone) - High 232 Th (high 230 Th initial) - Post-precipitation effects

6  18 O Diagenetic processes (evaluated by petrography to discard re-crystallization) Non-equilibrium fractionation (evaluated by  13 C vs  18 O correlation, replication or Hendy test)  18 O of rainfall Cave Tª (seasonally stable, long-term variations can modulate the signal) Other fractionation (eg. evaporation of water in the soil or vadose zone) Air temperature variations Variability in the precipitation sources Amount of precipitation 0.34‰/ºC NAO; glacial vs interglacial  13 C  13 C values of the carbonate bedrock (fixed values)  13 C values of the soil CO 2 Soil processes and residence time Type of vegetation overlying the cave (C3 vs C4) Speleothems as exceptional paleoclimate archives Mg/Ca, Sr/Ca, Ba/Ca Vegetation cover overlying the cave Marine aerosols – distance to the coast Prior calcite precipitation (link to dry/wet climates) A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula

7 A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula Study sites in the north of the Iberian Peninsula Cueva de las Güixas Cueva 5 de Agosto Sima de Estebán Felipe Cueva de Molinos Zonas calcáreas CAVECAL-CICYT: Cambios climáticos rápidos en la Península Ibérica basados en calibración de indicadores, series instrumentales largas y análisis de alta resolución de registros en espeleotemas. DGA-LaCaixa: Formaciones de espeleotemas en Aragón: una innovadora aproximación a la reconstrucción del clima de los últimos milenios. El Pindal and Calabrez caves

8 Pathway Old fluvial channel EL PINDAL Old alluvial deposits Block accumulations Mud deposits Flowstone Complex SpeleothemsFluviokarstic and gravity features Gours Dripstone Jiménez-Sánchez et al., 2002 non-dolomitic limestones of the Carboniferous Barcaliente Formation A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula R 2 =

9 5 de Agosto A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula First stalagmites dated from the Spanish Pyrenees. High altitude cave (1664 m) Monitoring in progress (temperature, rainfall, dripwaters)

10 A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula Main questions 1) Temporal and spatial reconstruction of main abrupt changes in the Northern Iberian Peninsula during the Pleistocene and Holocene 2) Interpretation of main mechanisms of abrupt climate change in the past, including phenomena affecting the most recent millennia (NAO, solar variability…) 3) Response of terrestrial ecosystems (hydrology, vegetation) to abrupt climate changes at different timescales (orbital, millennial, decadal)

11 A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula At an orbital-scale Espeleothems from 5 de Agosto Cave (Central Pyrenees) only growth during short periods associated to interglacials: OIS 1, OIS 7, OIS 9, OIS 11. Surprisingly, there is no sample (after dating 16 stalagmites) growing during OIS 5

12 A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula Isotopes  18 O values very similar in the three interglacials;  13 C has higher variability (particularly, OIS 7) Identify the growth periods as the warmer and wetter intervals Compare duration and characteristics of the last interglacials Look for an “analogous” for the Holocene (OIS 5??, OIS 11?) At an orbital-scale

13 During last deglaciation CANDELA CAN sample covers from 25 to 8 kyrs ago with an interruption during the Mystery Interval (Denton, 2005), a particular time period characterized by an increase in sea level but colder temperatures in Greenland and North Atlantic than during the LGM. We would expect a very cold, and probably dry, scenario for southern Europe. A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula

14 H1 YD IACP OD PB LGMHE  13 C (‰)  18 O (‰)  18 O (‰) NGRIP (GCC05) (Rassmussen et al. QSR 2008) Age (years BP) CANDELA MARIA HIATUS Mystery interval GI-1 HOLOCENEGS-1GS-2bGS-2aGi-2GS-2C Drier NAO + Wetter NAO - A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula During last deglaciation

15 A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula H1 YD IACP OD PB LGMHE2  18 O (‰) NGRIP (GCC05) (Rassmussen et al. QSR 2008) MARIA GI-1 HOLOCENEGS-1GS-2bGS-2aGi-2GS-2C  13 C (‰) Ba/Ca CANDELA Wetter Drier During last deglaciation

16  13 C (‰)  18 O (‰) HSG (detrended) Bond et al., 2001 A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula During the Early Holocene COLD WARM WET DRY

17 A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula  18 O (‰) MARÍA (this study)  18 O (‰) Dongge Cave (Dykoski et al., 2005) NGRIP Dongshiya Cave (Cai et al., 2008) PB During the Early Holocene

18 A. Moreno (IPE-CSIC)Speleothem records from the northern Iberian Peninsula Conclusions Speleothem records from Northern Spain are excellent paleoclimate records of past hydrological variability that need to be studied with further detail Growing periods in the Central Pyrenees are related to some interglacials pointing to the most humid and the warmest intervals for the last 400 kyrs. The driest period for the last 25 kyrs is the “mystery interval” as indicated by the hiatus Paleohydrological and vegetational response to the abrupt changes during deglaciation (HE1, B/A, oldest and older Dryas, IACP) and Early Holocene abrupt changes NAO-type mechanism behind abrupt climate changes recorded in the Iberian Peninsula?


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