Evolution Of The Westerly Winds Belt In The Middle Latitudes Of The Southern Hemisphere Since The Last Glacial Maximum

William Henriquez Gonzalez

doi:10.26686/wgtn.15145446

Abstract

Evolution Of The Westerly Winds Belt In The Middle Latitudes Of The Southern Hemisphere Since The Last Glacial Maximum

Highlights

The current glacial-interglacial cycle features a sequence of global climate and environmental changes at different timing, magnitude and direction, with the key features on these timescales being explained by invoking the Milankovitch theory of orbital forcing (e.g. Chapman et al, 2000; Langgut et al, 2011)
Ice-free conditions emerged at Lake Von no later than ~18.0 ka, leading to the rapid colonization, establishment and expansion of shrubs, herbs and ferns characteristic of alpine vegetation under relatively cold and humid conditions between ~18.0 and ~16.7 ka
I interpret these data as a modest increase in Southern Westerly Winds (SWW) influence, as a result of a northward shift or strengthening of the SWW following the onset of T1

Summary

Introduction

Subsequent increases in Nothofagus at various times (Figure 5.2, Table 5.1) led to woodland and forests which have persisted with little variation until the present (Fesq-Martin et al, 2004; Fontana and Bennett, 2012; Huber et al, 2004; Markgraf and Huber, 2010; Moreno et al, 2018b; Villa-Martínez and Moreno, 2007; Wille et al, 2007) Whilst these vegetation trends during T1 and the Holocene are broadly consistent throughout the region, less coherence is evident in the timing, millennial-scale structure and climatic interpretations of these vegetation changes, highlighting heterogeneities in stratigraphic and chronologic control, time span, sampling resolution and variations in depositional settings within and among study sites (Table 5.1). These depositional environments typically feature significant variations in sedimentation rates, alternation of subaqueous and subaerial deposition, and over-representation of local vegetation growing on the site surface, skewing the paleovegetation signal toward an extremely local record (Moreno et al, 2009a)

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Conclusion