Late Miocene vegetation and palaeoenvironments of the Drygalski Formation, Heard Island, Indian Ocean: evidence from palynology

• Main Authors: Truswell, Elizabeth, Quilty, Patrick G, McMinn, A, Macphail, Michael, Wheller, G E
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: British Antarctic Survey 2015
• Subjects: Keywords: Miocene; paleoenvironment; palynology; vegetation; Heard Island; Heard Island and McDonald Islands; Indian Ocean; Indian Ocean islands; oceanic regions; World; Asteraceae; Bacillariophyta; Filicophyta; Foraminifera; Gunnera; Lycopodium; Magnoliophyta; Nit Cape Lockyer; Kerguelen Plateau; Microfossils; Miocene diatoms; Southern Ocean; Sub-Antarctic; Vegetation history; Antarctic; The Antarctic; Kerguelen; Indian; Heard; McDonald Islands; Drygalski; Lockyer; Cape Lockyer; Antarc*; Antarctic Science; Tierra del Fuego
• Online Access: http://hdl.handle.net/1885/79757

Well sorted, fine lithic sandstone within the Drygalski Formation at Cape Lockyer on the southern tip of Heard Island, preserves a diverse terrestrial palynoflora as well as marine diatoms and a few foraminifera. A combination of these elements suggests a Late Miocene age (10-5 Ma). The palaeovegetation was markedly different from that presently on the island, and appears to comprise at least two ecologically distinct communities: open heath or herbfield dominated by grasses and Asteraceae, and a more mesophytic community dominated by ferns but also including lycopods and angiosperms such as Gunnera. This may have represented a coastal flora similar to the 'fern-bush' community that exists now on Southern Ocean islands north of the Antarctic Polar Frontal Zone, and in Tierra del Fuego; however, there is no evidence of tree species in the local flora and trace amounts of tree pollen present may have blown in from other landmasses in the region.