Two well-dated δ18O-speleothem records from Shatuca cave, situated on the northeastern flank of the Peruvian Andes (1960 m asl) were used to reconstruct high-resolution changes in precipitation during the Holocene in the South American Summer Monsoon region (SASM). The records show that precipitation increased gradually throughout the Holocene in parallel with the austral summer insolation trend modulated by the precession cycle. Additionally the Shatuca speleothem record shows several hydroclimatic changes on both longer- and shorter-term time scales, some of which have not been described in previous paleoclimatic reconstructions from the Andean region. Such climate episodes, marked by negative excursions in the Shatuca δ18O record were logged at 9.7–9.5, 9.2, 8.4, 8.1, 5.0, 4.1, 3.5, 3.0, 2.5, 2.1 and 1.5 ka b2k, and related to abrupt multi-decadal events in the SASM. Some of these events were likely associated with changes in sea surface temperatures (SST) during Bond events in the North Atlantic region. On longer time scales, the low δ18O values reported between 5.1-5.0, 3.5–3.0 and 1.5 ka b2k were contemporaneous with periods of increased sediment influx at Lake Pallcacocha in the Andes of Ecuador, suggesting that the late Holocene intensification of the monsoon recorded at Shatuca site may also have affected high altitudes of the equatorial Andes further north. Numerous episodes of low SASM intensity (dry events) were recorded by the Shatuca record during the Holocene, in particular at 10.2, 9.8, 9.3, 6.5, 5.1, 4.9, 2.5 and 2.3 ka b2k, some of them were synchronous with dry periods in previous Andean records.
Bibliographical noteFunding Information:
This research was undertaken as a part of the PALEOTRACES project (IRD, UPMC, UFF, Uantof, UPCH) and supported by the Brazilian National Council for Scientific and Technological Development – CNPq (grant 158894/2010-3 ) and the Fundação de Amparo a Pesquisa do Estado de São Paulo-FAPESP through the Dimensions of Biodiversity Program grants # 2012/50260-6 and # 2013/50297 and PRIMO cooperative project (CNPq – IRD) to F.W. Cruz. MV acknowledges support from NSF ( AGS-1303828 ). We thank Osmar Antunes for this support during the stable isotope data acquisition at São Paulo University. We also thank Augusto Auler, the Groupe Spéléo Bagnols Marcoule (GSBM) and the Espeleo Club Andino (ECA Perú) for the support during the collection of speleothems and for providing us the opportunity to work with them. We are grateful to Jhan Carlo Espinoza, who provided insight and expertise in Peruvian climatology, to Claire Lazareth, Bruno Turcq, Luc Ortlieb, Philip Meyers, J.B. Ponce, C.R. Grijalba and two anonymous reviewers, for their effort and time spent in discussions and comments that greatly improved the manuscript.
© 2016 Elsevier Ltd
- Northeastern Peruvian Andes
- South American Summer Monsoon
- Stable isotopes