Constant wind regimes during the Last Glacial Maximum and early Holocene: evidence from Little Llangothlin Lagoon, New England Tablelands, eastern Australia

Abstract

Abstract.Here we present the results of a multi-proxy investigation -integrating geomorphology, ground-penetrating radar, and luminescence dating -of a high-elevation lunette and beach berm in northern New South Wales, eastern Australia. The lunette occurs on the eastern shore of Little Llangothlin Lagoon and provides evidence for a lake high stand combined with persistent westerly winds at the Last Glacial Maximum (LGM -centring on 21.5 ka) and during the early Holocene (ca. 9 and 6 ka). The reconstructed atmospheric circulation is similar to the present-day conditions, and we infer no significant changes in circulation at those times, as compared to the present day. Our results suggest that the Southern Hemisphere westerlies were minimally displaced in this sector of Australasia during the latter part of the last ice age. Our observations also support evidence for a more positive water balance at the LGM and early Holocene in this part of the Australian sub-tropics.

Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia's arid margin interpreted from speleothem records (23–15 ka)

“…However, little is currently known about the impact of Heinrich stadials on Australian climate, and the Southern Hemisphere mid-latitudes in general, as reliable terrestrial paleoclimate records from this region are sparse (Broecker and Putnam, 2012). The latitudinal position of the westerly winds at the Last Glacial Maximum (LGM) is also an important research question which still remains debated despite long-running attention, both specifically in the southern Australian sector (Bowler, 1978;Bowler and Wasson, 1984;Wywroll et al, 2000;Shulmeister et al, 2004Shulmeister et al, , 2016Williams et al, 2009;Hesse et al, 2004;Turney et al, 2006;Haberlah et al, 2010;Cohen et al, 2011;De Deckker et al, 2012) and elsewhere in the Southern Hemisphere (Gasse et al, 2008;Kohfeld et al, 2013;Sime et al, 2013).…”

Last Glacial Maximum and Last Glacial–Interglacial Transition pollen record from northern NSW, Australia: evidence for a humid late Last Glacial Maximum and dry deglaciation in parts of eastern Australia

“…Recent work by Shulmeister et al . () at Little Llangothlin also supports this inference. Their results show a lake high stand during the latter part of the LGM, as evidenced by the formation of a lunette on the eastern shore at that time, which required wave‐driven sediment transport in the lake.…”

“…The presence of rainforest margin and/or wet schlerophyll taxa in the Little Llangothlin record suggests an easterly wind regime for the region. Winter westerlies did occur at this latitude in the LGM (Shulmeister et al ., , ; Petherick et al ., ) but the volume of moisture reaching this area would have been small. In fact, winter westerlies produce only a minor component of the modern rainfall at this site with most rainfall associated with moist easterly onshore winds from the Tasman Sea in the summer months.…”

“…This study showed that the last major phase of lunette formation occurred at ca. 19 ka during the late LGM and reflected strong westerly flow at this location, which is also near the northern limits of reliable winter westerly penetration (Shulmeister et al ., ).…”

Large mammal species richness and late Quaternary precipitation change in south‐western Australia

“…In contrast, drawing on lake level records across the continent, Harrison (1993) argues that reduced LGM lake levels reflect aridity caused by a poleward shift of the westerlies (see also Harrison and Dodson, 1993), which is also suggested by the general circulation model presented by Wyrwoll et al (2000;but see Shulmeister et al, 2004). More recently, it has been argued that there was little change in the winter westerly track in south-east Australia at the LGM (McGowan et al, 2008;Shulmeister et al, 2016). Conflicting interpretation of LGM palaeoclimate records and their implications for the position of the westerlies is not unique to Australia, but is typical of all southern hemisphere landmasses (Markgraf, 1987;Heusser, 1989;Lamy et al, 1999;Stuut et al, 2004;Chase and Meadows, 2007;Fletcher and Moreno, 2012;Faith, 2013).…”