Regional vegetation and climate changes during the last 13 kyr from a marine pollen record in Seno Reloncaví, southern Chile

Abstract : A marine pollen record from Seno Reloncaví (southern Chile, 41°S) illustrates temperate rainforest changes during the last 13 cal kyr BP. Our study shows the end of the last Termination at ~ 11.5-12 cal kyr BP coincident with the expansion of Weinmannia, illustrating disturbance and warming conditions, at the expense of cold-resistant conifers (Fitzroya-Pilgerodendron and Podocarpus). Warming conditions are strengthened at 10.7 cal kyr BP by the increase of heliophytic taxa (Eucryphia-Caldcluvia) characteristic of the Valdivian rainforest. These heliophytic taxa reach their maximum expansion between 9.6 and 7.4 cal kyr BP and point to warm and dry conditions during the Holocene Climatic Optimum. After 7.4 cal kyr BP, vegetation changes indicate variable climate conditions superimposed on a cooling trend associated with an increase in precipitation after ~ 6-5 cal kyr BP, shown by the expansion of the cold-resistant conifers. During the late Holocene, after 2.8 cal kyr BP, the continuous expansion of cold-resistant conifers marks an increase of cool and wet conditions. The comparison between marine and terrestrial pollen records highlights the similar trends and timing of vegetation changes that allows to complete the regional pattern of vegetation changes around Seno Reloncaví. In comparison with the terrestrial pollen records, this marine pollen record provides a more regional signal of vegetation/climate changes and clearly demonstrates the sensitivity of marine pollen records to past vegetation and climate change.