The Interpretation and Environmental Significance of a Buried Middle Pleistocene Soil Near Ipswich Airport, Suffolk, England

摘要: A buried Middle Pleistocene soil at Ipswich Airport, Suffolk, England, was studied by using macromorphological, textural, mineralogical, chemical and micromorphological techniques. This soil, developed on a low-level terrace surface in the Kesgrave Sands Gravels, beneath solifluction deposits Barham is composite of Valley Farm Soils which have been recognized over wide areas East Anglia. Clay illuviation, gleying, rubification (haematite formation) periglacial disruption were major pedogenic processes active during its formation; mineral weathering temperate pedoturbation appear to played only minor role. After deposition Gravels establishment stable land surface, clay translocated from eluvial horizons into lower illuvial horizons. Initially, this process consisted solely fine but as environment deteriorated, coarser more poorly sorted translocated. Biotic, shrink—swell or frost turbation led localized some limpid (fine) coatings before, simultaneous with, commencement phase illuviation. However, most fragmentation occurred later when had deteriorated one characterized seasonally frozen ground. At stage, silt grains small-scale contraction cracks microscale cryogenic features (silty cappings duplex textural lamellae features) formed. Further deterioration climate formation large-scale (or incipient ice) wedges, truncation two deposits. The older sediment contains components eroded horizons, whereas other deposit overlying (glacifluvial) contain minerals derived Anglian ice sheet. Airport Waldringfield Member Formation, assumed be Beestonian age. As sediments apparently deposited Stage, it appears that probably formed Cromerian early parts Anglian. Such chronology would not dispute with proposed environmental reconstruction largely pedological evidence, suggests simple optimum conditions. much depends significance first phase. If represents sharp climatic oscillation, stratigraphic implications may complex.