Oldest Dryas hydroclimate reorganization in the eastern Iberian Peninsula after the iceberg discharges of Heinrich Event 1

This study examines the first precisely dated and temporally highly resolved speleothem record from Iberia that reconstructs the Oldest Dryas (OD). The onset of cold conditions in the study area, contemporary with the beginning of Heinrich Stadial 1, is recorded at 18.13 +/- 0.08 ka, with a pronounc...

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Bibliographic Details
Published in:Quaternary Research
Main Authors: Perez-Mejias, Carlos, Moreno, Ana, Bernal-Wormull, Juan, Cacho, Isabel, Cinta Osacar, M., Lawrence Edwards, R., Cheng, Hai
Format: Report
Language:English
Published: CAMBRIDGE UNIV PRESS 2021
Subjects:
Speleothem
Deglaciation
Heinrich Stadial 1
Oldest Dryas
Iberia
Western Mediterranean
Atlantic Meridional Overturning Circulation
LAST GLACIAL MAXIMUM
ATLANTIC SURFACE HYDROGRAPHY
NORTH-ATLANTIC
CLIMATE VARIABILITY
ALBORAN SEA
VEGETATION HISTORY
SPELEOTHEM RECORD
HYDROLOGICAL VARIABILITY
EUROPEAN DEGLACIATION
REGIONAL CLIMATE
Physical Geography
Geology
Geography
Physical
Geosciences
Multidisciplinary
North Atlantic
Online Access:http://ir.ieecas.cn/handle/361006/16699
http://ir.ieecas.cn/handle/361006/16700
https://doi.org/10.1017/qua.2020.112
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Summary:This study examines the first precisely dated and temporally highly resolved speleothem record from Iberia that reconstructs the Oldest Dryas (OD). The onset of cold conditions in the study area, contemporary with the beginning of Heinrich Stadial 1, is recorded at 18.13 +/- 0.08 ka, with a pronounced drop of 6.1 parts per thousand in delta C-13 in 250 years. Henceforth, stadial conditions depict a period of instability in the Atlantic Meridional Overturning Circulation, peaking in freshwater input from iceberg melting during Heinrich Event 1. Anomalies in the delta O-18 of the stalagmite attributed to such a freshwater event are found from 16.17 to 15.89 ka. Such absolute dates given to the onset of the OD in Iberia and to the main iceberg discharges are reliable anchor points for non-absolute chronologies. Two periods are identified in the OD: OD-a (18.13-16.17 ka) is characterized by wet conditions and a faster growth rate, and OD-b (15.89-14.81 ka) exhibits relative dryness and a slower growth rate. The sudden release of fresh water is considered to be the reason for the disruption of rainfall patterns in eastern Iberia. The present study also highlights the existence of heterogeneous and complex hydrological conditions during the OD in Iberia when both Atlantic and Mediterranean realms are considered.

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