Southern hemisphere patterned mires, with emphasis on southern New Zealand

Abstract

Extensive patterned mires in valley heads and on glacial benches in southern New Zealand: (45° 22'S; 1250–1400 m a.s.l.), and valley floors in Tierra del Fuego (54° 53'S; 60–100 m a.s.l.) have developed under cool, moist climatic conditions favourable for peat accumulation. In southern New Zealand's tussock grassland landscape, aapa mire pools (often with peat islands) and ridges, are elongated (pools: mean 24.5 ± 2.4 m × 7.5 ± 1.0 m) and aligned 90° to gentle slopes. Peat depths (0.3–2.5 m) are greatest on downslope margins of pools and sometimes associated with basement profile concavities. Pools up to 1.3 m deep have peat bases, are generally not fed by nor linked to surface streams, and have steep downslope, with more gentle upslope, margins. Pools may be incipient (occupying small peat depressions), fluctuating or permanent. In steeper headwater sections, surface and underground channels link small stream pools. On glacial benches, pools (to 1 ha) occupy basement rock depressions with up to 1.5 m of ...