TY  - JOUR
A1  - Apaestegui, James
A1  - Cruz, Francisco William
A1  - Vuille, Mathias
A1  - Fohlmeister, Jens Bernd
A1  - Carlo Espinoza, Jhan
A1  - Sifeddine, Abdelfettah
A1  - Strikis, Nicolas
A1  - Guyot, Jean Loup
A1  - Ventura, Roberto
A1  - Cheng, Hai
A1  - Edwards, R. Lawrence
T1  - Precipitation changes over the eastern Bolivian Andes inferred from speleothem (delta O-18) records for the last 1400 years
JF  - Earth & planetary science letters
N2  - Here we present high-resolution delta O-18 records obtained from speleothems collected in the eastern Bolivian Andes. The stable isotope records are related to the regional- to large-scale atmospheric circulation over South America and allow interpreting changes in delta O-18 during the last 1400 yr as a function of changes in precipitation regimes over the southern tropical Andes. Two distinct phases with more negative delta O-18 values, interpreted as periods of increased convective activity over the eastern Andean Cordillera in Bolivia are observed concomitantly with periods of global climate anomalies during the last millennium, such as the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) respectively. Changes in the Bolivian delta O-18 record during the LIA are apparently related to a southward displacement of the Intertropical Convergence Zone (ITCZ), which acts as a main moisture driver to intensify convection over the tropical continent. During the MCA, however, the increased convective activity observed in the Bolivian record is likely the result of a different mechanism, which implies moisture sourced mainly from the southern tropical Atlantic. This interpretation is consistent with paleoclimate records further to the north in the tropical Andes that show progressively drier conditions during this time period, indicating a more northerly position of the ITCZ. The transition period between the MCA and the LIA shows a slight tendency toward increased delta O-18 values, indicating weakened convective activity. Our results also reveal a non-stationary anti-phased behavior between the delta O-18 reconstructions from Bolivia and northeastern Brazil that confirms a continental-scale east-west teleconnection across South America during the LIA.
KW  - speleothems
KW  - stable isotopes
KW  - MCA
KW  - LIA
KW  - Bolivia
KW  - South American Monsoon
Y1  - 2018
U6  - https://doi.org/10.1016/j.epsl.2018.04.048
SN  - 0012-821X
SN  - 1385-013X
VL  - 494
SP  - 124
EP  - 134
PB  - Elsevier
CY  - Amsterdam
ER  -