A MID OTIRA GLACIATION PALEOSOL AND FLORA FROM THE CASTLE-HILL BASIN,CANTERBURY, NEW-ZEALAND

A section exposed at the Broken River road cutting in Castle Hill Basi n revealed a palaeosol resting on reddish, rusty gravel and beneath 30 m of fresh-looking, grey, glacio-fluvial outwash gravel deposited by a meltwater stream during the Blackwater advances of the Waimakariri G lacier. A radiocarbon date >37 000 +/- 200 yr B.P. (NZ 7518) was obtai ned for the palaeosol. Pollen spectra from it are dominated by a herba ceous plant assemblage indicating cold climatic conditions. Redeposite d pollen from adjacent Tertiary rocks is also present. The soil appear s to have been formed in a marshy habitat soon after the onset of the Blackwater 1 glacial episode (the first cold phase of the middle part of the Otira Glaciation).