A Holocene record of climate and hydrological changes from Little Llangothlin Lagoon, south eastern Australia

Abstract

We present a new well dated Holocene record of environmental change from Little Llangothlin Lagoon in eastern Australia derived from aquatic plant macrofossils, macroscopic charcoal flux, and sediment stratigraphy from multiple cores. Little Llangothlin was an ephemeral freshwater wetland exhibiting frequent dry phases between 9800 and 9300 calendar years before present (cal. yr BP). There was a switch to a more positive water balance after 9300 cal. yr BP, and by 8000 cal. yr BP, there was a lake that persisted until 6100 cal. yr BP. The period between 6100 and 1000 cal. yr BP was much drier, and there is no evidence for a permanent lake during this period. The Little Llangothlin record provides evidence for a wet phase during the Early to Middle Holocene (9000–6000 cal. yr BP) from the boundary region between temperate and tropical influences in eastern Australia. We propose that generally enhanced circulation after 9000 cal. yr BP explains the pattern of increasing moisture at the site at this time. The later Holocene climate at the site is consistent with other sites in south east Australia with a switch to generally drier conditions after 6000 cal. yr BP.

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

“…For the intervening periods, at least in the Holocene, the evidence (Woodward et al, 2014a) suggests that water levels were lower and/or even that the lake was ephemeral. It is highly unlikely that sand would be transported to the highstand beach during low lake levels.…”

“…400 mm (Woodward et al, 2014a). The regional vegetation is dominated by montane open eucalypt woodland, while the lagoon itself contains extensive beds of tall spike rush (Eleocharis sphacelata) and the water plant Potamogeton tricarinatus in the deeper parts of the basin.…”

“…Furthermore, the site has been identified as a location of exceptional soil erosion since European settlement (Gale et al, 1995;Gale and Haworth, 2005), although this has recently been chal-lenged (Woodward et al, 2011). The site has more recently become a focus for work due to inferred changes to basin hydrology in response to tree clearance during European settlement of the New England Tablelands (Woodward et al, 2014a). There has also been some investigation of the archaeological history of the lagoon suggesting that landscapes such as these provided relatively rich resources for Aboriginal people and that New England lagoons became the foci for ceremonial activities, although the degree to which hydrological conditions influenced human activity remains poorly understood since chronological control for the pre-European period has so far been lacking (Beck et al, 2015).…”

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

“…Previous coring by the authors recovered a Holocene record from Little Llangothlin Lagoon (Woodward et al ., ) but from earlier work (R. Haworth, pers comm. 2011) we were aware that pre‐Holocene records were available from the basin.…”

“…Evaporation data are not available for Guyra but a mean evaporation total of 1262 mm was calculated by Woodward et al . (,) using the Penman equation. This suggests a modest annual water deficit of ca.…”