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

• Published in: Antarctic Science
• Main Authors: TRUSWELL, ELIZABETH M., QUILTY, PATRICK G., MCMINN, A., MACPHAIL, M.K., WHELLER, G.E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2005
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; Southern Ocean; The Antarctic; Heard Island; Indian; Drygalski; Lockyer; Cape Lockyer; Antarc*; Antarctic Science; Tierra del Fuego
• Online Access: http://dx.doi.org/10.1017/s0954102005002865; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102005002865

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.