A pluvial episode identified in arid Australia during the Medieval Climatic Anomaly

Abstract

Optically stimulated luminescence (OSL) ages from a relict shoreline on Lake Callabonna record a major pluvial episode in southern central Australia between 1050 ± 70 and 1100 ± 60 Common Era (CE), within the Medieval Climatic Anomaly (MCA). During this pluvial interval Lake Callabonna filled to 10-12 times the volume of the largest historical filling (1974) and reached maximum depths of 4-5 m, compared to the 0.5-1.0 m achieved today. Until now there has been no direct evidence for the MCA in the arid interior of Australia. A multi-proxy, analogue-based atmospheric circulation reconstruction indicates that the pluvial episode was associated with an anomalous meridional atmospheric circulation pattern over the Southern extratropics, with high sea-level pressure ridges in the central Indian Ocean and Tasman Sea, and a trough extending from the Southern Ocean into central Australia. A major decline in the mobility of the Australian aboriginal hunter-gatherer coincides with this MCA period, in southern central Australia. AbstractOptically stimulated luminescence (OSL) ages from a relict shoreline on Lake Callabonna

A soil Chronosequence on Lake Mega-Frome Beach Ridges and its Implications for Late Quaternary Pedogenesis and Paleoenvironmental Conditions in the Drylands of Southern Australia

“…Pit SC5A). Thus the combined geomorphic, chronological, and soil chemical observations for the soils exposed in Pits SC6A and SC5A appear to provide pedogenic evidence supporting the occurrence of regional late Holocene wet phases Cohen et al, 2011;Cohen et al, 2012a;Cohen et al, 2012b;Gliganic et al, 2014).…”

“…2, 3c, Table 1; Cohen et al, 2012a). Two stratigraphic units composed of partially landward dipping high-energy beach sands and gravel were observed in Pit SC6A (Figs.…”

“…At Lake Frome, a number of studies utilized lake sediments (Draper and Jensen, 1976;Bowler et al, 1986;Ullman and Collerson, 1994) and pollen or microfaunal remains (Singh, 1981;Singh and Luly, 1991;Luly, 2001;De Deckker et al, 2011) to develop a palaeoclimatic framework for the region. More recent efforts have predominantly focused on the analysis of Palaeoshoreline deposits Cohen et al, 2011;Cohen et al, 2012a;Cohen et al, 2012b). Their detailed topographic survey (DeVogel et al, 2004;Leon and Cohen, 2012) has placed new constraints on variations in lake levels and water volume.…”

A synoptic climatology of heavy rain events in the Lake Eyre and Lake Frome catchments

“…The larger arid-zone lake systems also record a long history of fluctuating climate with the work of Magee et al (2004) and Cohen et al (2011Cohen et al ( , 2012a all demonstrating that these inland catchments were much wetter about 100,000-50,000 years ago than at present with the presence of large "megalakes" and associated Pleistocene megafauna (Webb, 2010). Even more recently in the geological past (e.g., the medieval climatic anomaly, ∼1000 years ago) it has been shown that the Lake Frome-Callabonna system experienced exceptionally wet events that produced aggradational evidence of past lake filling (Cohen et al, 2012b;Gliganic et al, 2014).…”

All mixed up: Using single-grain equivalent dose distributions to identify phases of pedogenic mixing on a dryland alluvial fan

“…The finite mixture model (FMM) can be used to identify discrete D e components within a distribution Galbraith and Roberts, 2012), and it has been used to elucidate OSL chronologies in complex archaeological (David et al, 2007;Jacobs et al, 2008;Lombard et al, 2010;Gliganic et al, 2012), aeolian (Lomax et al, 2011), shoreline (Cohen et al, 2011(Cohen et al, , 2012a, fluvial (Rodnight et al, 2005), and glacial (Duller, 2006) settings. In environments where postdepositional mixing by pedoturbational processes (e.g., bioturbation or argilliturbation; Hole, 1961;Johnson et al, 1987;Schaetzl and Anderson, 2005) is particularly prevalent however, obtaining a depositional age is still challenging (Feathers et al, 2006;Bateman et al, 2007b;Rhodes et al, 2010;Tribolo et al, 2010;Chazan et al, 2013).…”