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

M.h.m Groot ,R G Bogotá,E Tuenter,M Van Der Linden,H Hooghiemstra,M Konert,A Betancourt,B Van Geel,T Van Der Hammen,Lineth Contreras ,Jef Vandenberghe ,Lucas Joost Lourens ,Catalina Giraldo ,Orlando Rangel ,Delia Ortega ,Shlomo Weber ,Martin Ziegler ,J H Fred Jansen ,Norma Emilia González ,Sergio Gaviria ,Johannes Van Der Plicht ,Juan Carlos Berrío ,Gustavo Sarmiento ,Mirjam Vriend ,W.e Westerhoff

doi:10.5194/cp-7-299-2011

Abstract

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.

Highlights

Long, high-resolution records of climate change are mainly inferred from the ice cores of Greenland and Antarctica (GRIP-Members, 1993; Grootes et al, 1993; Jouzel et al, 2007; North Greenland Ice Core Project (NGRIP)-Members, 2004; Parrenin et al, 2007; Svensson et al, 2008), marine sediments (Bond et al, 1993; Martrat et al, 2007; Peterson et al, 2000), and speleothems (Cheng et al, 2009; Wang et al, 2008)
The power distribution is much more smoothed in the BT spectrum, strong peaks occur at ∼9 and 25 m; consistent with the CLEAN estimates (Fig. 5b)
The REDFIT power estimate and distribution are in close agreement with that of the BT and CLEAN methods, an additional peak occurs at 1193 cm (Fig. 5b and d)

Summary

Introduction

High-resolution records of climate change are mainly inferred from the ice cores of Greenland and Antarctica (GRIP-Members, 1993; Grootes et al, 1993; Jouzel et al, 2007; NGRIP-Members, 2004; Parrenin et al, 2007; Svensson et al, 2008), marine sediments (Bond et al, 1993; Martrat et al, 2007; Peterson et al, 2000), and speleothems (Cheng et al, 2009; Wang et al, 2008). M. Groot et al.: Ultra-high resolution pollen record from the northern Andes and glacial-induced ice volume variations, rather than their surrounding lowlands. Groot et al.: Ultra-high resolution pollen record from the northern Andes and glacial-induced ice volume variations, rather than their surrounding lowlands These high altitude tropical settings lack, the necessary high-resolution and accurate records to fully explore the operating mechanisms of the Earth’s climate system over longer periods of time

Methods

Results

Discussion

Conclusion