Austrochlamys heardensis (Fleming, 1957) (Bivalvia: Pectinidae) from Central Kerguelen Plateau, Indian Ocean: palaeontology and possible tectonic significance

Abstract

Austrochlamys heardensis (Fleming) is recorded from a boulder of Late Pliocene (3.62–2.5 Ma) volcaniclastic sandstone dredged 70 km east-north-east of Heard Island, the third record of the species. The collection is much larger than the original described by Fleming and includes left valves which are described for the first time. The species is compared with A. anderssoni (Hennig) from Cockburn Island and ‘Chlamys’ mawsoni Fletcher from Îles Kerguelen. The source rock accumulated in fully marine, highly current-affected conditions. The collection is dominated by right valves, possibly because left valves are more susceptible to breakage and the effects of current winnowing. The locality may have subsided some 500 m since deposition. It lies immediately north of a straight, north-east–south-west trending lineament which may mark a major tectonic feature with left-lateral displacement of approximately 50 km, and provides a natural boundary within the Central Province of Kerguelen Plateau.

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

“…1) by R.S. Cohen and D. Lawton in 1969(Jonkers 2003, Quilty 2004. This find enlarged the known extent of the fossiliferous sediment facies of the Drygalski Formation and also the distribution of the bivalve around the island.…”

“…Lambeth (1952) and Stephenson (1964) also referred to glacial sediments in the Drygalski Formation but these have not been documented. The Drygalski Formation was the source of the bivalve Austrochlamys heardensis (Fleming) (Fleming 1957, Jonkers 2003, Quilty 2004 on the southern side of Laurens Peninsula, close to the locality chosen by Lambeth (1952) as part of the type locality for the Drygalski 'Agglomerate', where there are said to be '…glacial sediments with associated lavas…' (Stephenson 1964). The original location of the fossil in the section is unknown.…”

The Kerguelen plateau: Records from a long-living/composite microcontinent

“…Islands. Quilty (2004) already mentioned a NE-SW trending lineament, likely to account for a major tectonic feature with a left-lateral displacement of approximately 50 km, providing a natural boundary within the Central Province of the Kerguelen Plateau.…”

EarlyMioceneMollusca fromMcMurdoSound,Antarctica (ANDRILL2Adrill core), with a review ofAntarcticOligocene andNeogenePectinidae (Bivalvia)

“…Miocene, Laurens Peninsula, Heard Island; Corinth Head, Heard Island (USGS 25002, 2 valves, in USNM; not seen; Jonkers , p. 83); large sample (not seen) from block of rock dredged in 579 m of water 70 km NE of Heard Island, dated at 3.62–2.5 Ma (late Pliocene, Piacenzian) by diatom biostratigraphy (Quilty et al . ).…”