Geoscience Reference
In-Depth Information
Figure 1.3
Geology of Upper Wharfedale,
North Yorkshire.
of the river Wharfe and its tributaries have been carrying
out fluvial action, with periods of incision (i.e. vertical
erosion) alternating with periods of lateral channel
migration and aggradation (i.e. deposition of sediments)
to produce prominent alluvial terraces. River action in the
early Holocene epoch was mainly a reworking of coarse
cobbles and rocks from Pleistocene glacial materials, but
more recent terraces are composed of finer-grained
sediments produced by the erosion of hill slopes.
After the final retreat of the ice sheets and valley
glaciers, the dale was recolonized by natural vegetation
and associated wildlife. Birch and pine trees arrived quite
quickly, followed by larger broad-leaved trees in early
postglacial times. Ecological and anthropogenic impacts
have had a great influence on the environmental systems
of Upper Wharfedale ever since. Here, as wherever there
are human settlement and land use, human activities have
modified landforms and soils, and created new patterns
