Lateglacial and early Holocene glaciation in the tropical Andes caused by La Ni?a-like conditions

摘要

The response of the tropics to North Atlantic cold events, such as Heinrich Event I (H-I, ~ 17-15. ka) and the Younger Dryas (YD, 12.7-11.5. ka), is still one of the most tantalizing, yet unresolved issues in paleoclimatology. The advent of surface exposure dating has therefore instigated the establishment of glacial chronologies in the tropical Andes to investigate potential climate teleconnections. Here, we present new exposure ages from the Cordillera Cochabamba (17°17'S), Bolivia, that reveal glacial advances during H-I and YD, as well as during the Early Holocene. Our chronology correlates well with cold sea surface temperatures in the eastern tropical Pacific, which indicates that La Ni?a-like conditions, i.e. forcings intrinsic to the tropics, played a key role for moisture advection and glaciation in the tropical Andes.