Soil development, environmental history and the dating of terraced valley fill deposits in the North York Moors, with specific reference to Dovedale Griff and Jugger Howe Beck
Detailed investigation of the valley fill deposits of Dovedale Griff and Jugger Howe Beck, together with a sedimentological and palaeomagnetic investigation of the sediments of Lake Gormire, provide the basis for an integrated analysis of the temporal and palaeoenvironmental aspects of Holocene valley floor landform development in the North York Moors. A Holocene alluvial chronology is developed for Dovedale Griff and Jugger Howe Beck based on surface soil stratigraphy, radiocarbon dating, morphology and sediment stratigraphy. Surface soils developed into the deposits of the Dovedale Griff terrace fragments are divided statistically into three groups of soils using a combination of Principal Components Analysis and Cluster Analysis. The first principal component is shown to be a compound index of soil properties that represent some of the main morphological and chemical properties of brown podzolic soils and the grouped soils are shown to represent a chronosequence of brown podzolic soils. Each cluster of soils represents one soil stratigraphic unit. The age-calibrated surface soil stratigraphic units from Dovedale Griff are used in a Discriminant Analysis procedure to estimate the ages of undated valley floor surfaces in Jugger Howe Beck. An additional soil stratigraphic unit is identified from Jugger Howe Beck. This fourth unit is shown to have a freely drained phase and a gleyed phase. In Dovedale Griff the alluvial surfaces are dated to about 7100BP, 900BP and about 300BP. In Jugger Howe Beck the main alluvial surfaces are shown to be about 10000BP, 900BP and about 300BP in age. These phases of valley floor development are correlated with phases of instability and stability as revealed by erosion indicators from the sediments of Lake Gormire. Two main phases of synchronous behaviour between the three sites are Identified and their environmental significance discussed. These phases occurred at about 1000 - 900BP and again around about 300BP. A phase of synchronous behaviour between Jugger Howe Beck and Gormire are identified atabout 10000BP. Phases of site specific behaviour are also identified at 7100BP in Dovedale and 2500BP in Lake Gormire. The Holocene environmental changes in the North York Moors are placed In the context of valley floor development In upland Britain. Chronologies of valley floor development for upland regions may not reveal a common temporal pattern of response.