Ultra-high resolution pollen record from the northern Andes reveals rapid shifts in montane climates within the last two glacial cycles

Abstract

Here we developed a composite pollen-based record of altitudinal vegetation changes from Lake Fúquene (5° N) in Colombia at 2540 m elevation. We quantitatively calibrated Arboreal Pollen percentages (AP%) into mean annual temperature (MAT) changes with an unprecedented ~60-year resolution over the past 284 000 years. An age model for the AP% record was constructed using frequency analysis in the depth domain and tuning of the distinct obliquity-related variations to the latest marine oxygen isotope stacked record. The reconstructed MAT record largely concurs with the ~100 and 41-kyr (obliquity) paced glacial cycles and is superimposed by extreme changes of up to 7 to 10° Celsius within a few hundred years at the major glacial terminations and during marine isotope stage 3, suggesting an unprecedented North Atlantic – equatorial link. Using intermediate complexity transient climate modelling experiments, we demonstrate that ice volume and greenhouse gasses are the major forcing agents causing the orbital-related MAT changes, while direct precession-induced insolation changes had no significant impact on the high mountain vegetation during the last two glacial cycles

Nature and causes of Quaternary climate variation of tropical South America

“…Sediments deposited prior to the Holocene show the expansion of Podocarpus and other cool-adapted taxa, possibly indicating the downslope migration of high-elevation taxa during glacial times. The migration of taxa along elevation gradients is a common pattern in records from the Andean slopes and adjoining areas (Bush et al, 2004b;Groot et al, 2011) and produced new mixtures of taxa that likely affected multiple aspects of ecosystem structure and function, as well as evolutionary processes.…”

A climatic trigger for catastrophic Pleistocene-Holocene debris flows in the Eastern Andean Cordillera of Colombia

“…Paleoclimate records and glacial geomorphology studies indicate high climate variability for this region throughout the Pleistocene and Holocene, with a series of alternating stadials and interstadials up to the Holocene interglacial (Helmens, ; Van der Hammen, ; Groot et al ., ). The OSL age of ∼38 ± 3 ka for the deposits is close to the timing of Greenland interstadial 8 (Grootes et al ., ), and marks the Tenjo interstadial in the Colombian Andes (Van der Hammen, ).…”

Caracterización De La Acumulación De Carbono en Pequeños Humedales Andinos en La Cuenca Alta Del Río Barbas (Quindío, Colombia)

“…La edad del humedal BB, estimada en 5.150 años puede estar relacionada con el inicio de un período más húmedo y frío en los Andes colombianos del cual existen evidencias en la cordillera Occidental en el páramo de Frontino empezando hace 3.900 años (Velásquez & Hooghiemstra 2013), en la cordillera Oriental en la laguna de Fúquene empezando hace 11.900 años (Groot et al 2011 El estudio palinológico realizado para el humedal BB (Muñoz-Uribe 2007) permitió establecer coincidencias climáticas con las encontradas en el páramo de Frontino (Velásquez 2005) y los resultados de ambos estudios son importantes para entender las variaciones en la acumulación de carbono del presente estudio. Ambos estudios demuestran la ocurrencia de un período particularmente caliente y seco con las mayores temperaturas entre 1.400 y 1.300 años BP.…”