Loess of Banks Peninsula

Abstract

Abstract The loess of Banks Peninsula is divided into two distinct types which are named after the type sections, the Birdlings Flat loess and the Barrys Bay loess. The Birdlings Flat loess is calcareous and is coarser than the Barrys Bay loess, with textures of loamy fine sand and fine sandy loam. Two major layers are found separated by a paleosol and a slightly stony colluvial layer. This loess is found on the lower flanks of the Lyttelton caldera and on the western side of the Akaroa caldera. The Barrys Bay loess is fine with a silt loam texture and has 3 major layers and a minor one separated by 3 paleosols, overlying basalt or basalt soil. Charcoal and humic acid are found associated with these paleosols and a date (NZ 1163) from the uppermost paleosol gives an age of 17 450 ± 2070 years B.P. This type of loess is found on the upper parts of the Lyttelton caldera and on the eastern side of the Akaroa caldera. The loess was derived from the floodplain and fan of the Waimakariri River.