Stratigraphy, Pollen Analysis, and Paleoclimatic Interpretation of Pulbeena Swamp, Northwestern Tasmania

Abstract

Sedimentary, palynologic, and 14C analysis of 480 cm of freshwater marl and swamp-peat deposits, formed under the influence of fluctuating artesian springs, provides a paleoenvironmental and paleoclimatic record of approximately 65,000 yr for northwestern Tasmania.The Holocene (Pollen Zone 1, 11,000-0 yr B.P.) climate was warm and moist, and forest vegetation was dominant throughout the area. During the later part of the last glacial stage (Pollen Zone 2, 35,000–11,000 yr B.P.) the climate was generally drier, and grassy open environments were widespread. The driest part of this period occurred between 25,000 to 11,000 yr B.P., when temperatures in western Tasmania were markedly reduced during the last major phase of glaciation. Prior to 35,000 yr B.P. (Pollen Zones 3–9) a long “interstadial complex” dating to the middle of the last glacial stage is recognized. During this period the climate was generally moist, and forest and scrub communities were more important than during the later part of the last glacial stage, except during Pollen Zone 5 when high Gramineae plus Compositae values suggest drier conditions. High Gramineae and Compositae values also occur in Pollen Zone 10 at the base of the diagram. They suggest that a phase of drier and cooler climatic conditions occurred during the early part of the last glacial stage.

Climatic records over the past 30 ka from temperate Australia – a synthesis from the Oz-INTIMATE workgroup

“…An exception is the record from 30 ky Lake Surprise, southern Victoria, which although dominated by Asteraceae, shows a peak in Eucalyptus during the LGM (Builth et al, 2008). An open landscape is also inferred from Tasmanian pollen records, which are characterised by an increase in the importance of alpine/subalpine herbland/shrubland plant assemblages (Colhoun et al, 1982;Colhoun, 1985b;Colhoun et al, 1999). Charcoal records generally indicate relatively high biomass burning until ca.…”

“…Ages <2 ka are excluded and the weighted mean age is plotted for bedload units with multiple dates. LGM, (c) the deglacial period, (d) early to midHolocene and (e) mid to late Holocene, indicating the position of oceanic fronts and currents (Martinez 1994;Passlow et al 1997;Martinez et al 1999;Troedson and Davies, 2001;Barrows and Juggins, 2005;Bostock et al, 2006;Pelejero et al, 2009;Sikes et al 2009), relative SSTs (Passlow et al, 1997;Bostock et al, 2006;Calvo et al, 2007;Moros et al, 2009;Sikes et al, 2009;De Deckker et al, 2012), the changing extent of the Australian coastline (Lambeck and Chappell, 2001;Gillespie, 2002), glacial extent (Barrows et al, 2001;Barrows et al, 2002), hydrological activity (Page et al, 1991;Kemp and Rhodes 2010;Cohen et al, 2011) and climatic conditions inferred from pollen records from Native Companion Lagoon , Redhead Lagoon , Caledonia Fen (Kershaw et al, 2007); Lake Leake (Dodson, 1974;Dodson, 1975), Lake Wyrie (Dodson, 1977), Lake Selina (Colhoun et al, 1999), Pulbeena Swamp (Colhoun et al, 1982). Where STF = subtropical front, TF = Tasman Front, FUC = Flinders Undercurrent, EAC = East Australian Current.…”

Paleoclimates in Southwestern Tasmania during the Last 13,000 Years

“…Even though several pollen records from Tasmania extend beyond the full-glacial (Colhoun et al, 1982;Macphail and Colhoun, 1985), our paper addresses only the last 13,000-years-B.P. interval.…”

Peopled Landscapes: Archaeological and Biogeographic Approaches to Landscapes

“…The regional vegetation had the structure of a savanna or grassland, with sparse trees, while the swamps were covered with sedges (Colhoun et al 1982;van de Geer et al 1986). …”

“…comm. ) 23 Lake Johnson (Anker et al 2001) 24 Lake St Clair (Hopf et al 2000) 25 Lake Selina (Colhoun et al 1999) 26 Lake Tiberias (Macphail and Jackson 1978) 27 Lake Vera (Macphail 1979) 28 Mathinna Plains (Thomas 1996) 29 Melaleuca Inlet (Thomas 1995) 30 Mowbray Swamp (van de Geer et al 1986) 31 Newall Creek (van de Geer et al 1989) 32 Newton Creek 33 Ooze Lake (Macphail and Colhoun 1985) 34 Pedder Pond (Fletcher and Thomas 2007a) 35 Pieman Dam (Augustinus and Colhoun 1986) 36 Pipe Clay Lagoon (Colhoun 1977a) 37 Poets Hill Lake (Colhoun 1992) 38 Pulbeena Swamp (Colhoun et al 1982) 39 Remarkable Cave (Colhoun 1977b) 40 Rocky Cape (Colhoun 1977c) 41 Smelter Creek 42 Snow Hill Marshes (C. Becker 2000 pers. comm.)…”