Stratigraphic palynology in porous soils in humid climates: An example from Pouerua, Northern New Zealand

Abstract

Palynological data are presented for a basaltic soil from an archaeological site in northern New Zealand. The profile encompasses two successive soils at the base of Pouerua crater where the initial soil was buried during an erosion and depositional event. The soils have not been disturbed directly by people, and mixing by bioturbating invertebrates has been minimal resulting in a crude stratification of percolated pollen and microscopic charcoal. Forest in the base of the crater escaped the large-scale anthropogenic burning on the outer slopes of the cone and its surrounds indicated by earlier studies. Despite high soil porosity in a humid climate at Pouerua, the rate of pollen percolation in the crater soils is low, occurring at < 1 cm in 17.86 years (< 0.056 cm per year). These preliminary results show that soils with high infiltration rates in humid climates are potentially stratified and thus useful in providing records of local environments.

Effects of Holocene climate change, volcanism and mass migration on the ecosystem of a small, dry island (Brava, Cabo Verde)

“…Past environmental change can be reconstructed through the integration and nuanced interpretation of multiple proxies extracted from stratigraphically oriented sediments in soil profiles. Soils are not inert, and taphonomical and soil‐formation processes affect micro‐fossil preservation and mobility within the sediment matrix (Horrocks & D'Costa, 2003). In the Cova Galinha soil profile there were sections barren of palynomorphs, and some horizons composed of high proportions of sand contained pollen grains affected by degradation processes, probably due to mechanical weathering and oxidation (Figure S5).…”

“…Past environmental change can be reconstructed through the integration and nuanced interpretation of multiple proxies extracted from stratigraphically oriented sediments in soil profiles. Soils are not inert, and taphonomical and soilformation processes affect micro-fossil preservation and mobility within the sediment matrix (Horrocks & D'Costa, 2003). In the Cova Galinha soil profile there were sections barren of palynomorphs, and some horizons composed of high proportions of sand contained pollen grains affected by degradation processes, probably due to F I G U R E 4 CCA and DCA plots of the Cova Galinha record, Brava Island, Cabo Verde, using pollen percentage data (DCA), as well as concentrations of obligate coprophilous fungi for herbivore presence, LOI (%) for organic matter, find sand (%) for erosion, tephra shard concentrations for ash falls and Fe/Mn ratio for soil reducing conditions (CCA).…”

Arthropod colonisation of a debris-covered glacier

“…This could be owed to the significant prior felling of Quercus during the early late 18th and early 19th centuries, as a result of the need for timber in the naval industry and oak bark in the tanning industry (Linnard, 2000;Rackham, 1990). However, the very high percentage of ferns in this zone could be an indication of poor pollen preservation leading to the loss of other taxa, especially considering the high clay content of these sediments (Horrocks and D'Costa, 2003). At the end of zone BH-1, the marked decrease in Alnus pollen may indicate a shift towards drier conditions (Lamb, 1977), due to the sensitivity of Alnus to hydrological changes (Rodríguez-González et al, 2014).…”

Scots pine (Pinus sylvestris) dynamics in the Welsh Marches during the mid to late-Holocene

“…This could be owed to the significant prior felling of Quercus during the early late 18th and early 19th centuries, as a result of the need for timber in the naval industry and oak bark in the tanning industry (Linnard, 2000; Rackham, 1990). However, the very high percentage of ferns in this zone could be an indication of poor pollen preservation leading to the loss of other taxa, especially considering the high clay content of these sediments (Horrocks and D’Costa, 2003). At the end of zone BH-1, the marked decrease in Alnus pollen may indicate a shift towards drier conditions (Lamb, 1977), due to the sensitivity of Alnus to hydrological changes (Rodríguez-González et al, 2014).…”