York model information

York Minster

This model covers 50 km2 of terrain to the north and east of York including in the north the village of Haxby.

The model was built by the BGS in 2005 as a result of a recent integrated 1:10 000 survey and model building programme for the Selby and York areas.

It considers available borehole evidence, and extends to about 50 m depth. The model has been calculated using a digital elevation model (DEM) with a 25 m grid spacing and is best viewed with a vertical exaggeration of about x10.

At high vertical exaggerations, despite processing, some residual effects, mainly due to local woodland, can still be seen in the top model surface.

The area lies within the low lying Vale of York where deposits from the last glaciation (Devensian) often rest directly on the eroded and planed Triasssic bedrock.

Superficial geology

The model shows the Recent alluvial tracts of the Ouse in the extreme south-west and its tributary the Foss. The Devensian glacial sequence contains interbedded arrangement of outwash glaciofluvial deposits, ponded glaciolacustrine silts and clays and till (Vale of York Till) deposited directly from the icesheet. The Vale of York Till forms the core of the York Moraine, which is a low ridge near the southern end of the model; this moraine, and others in the region, mark positions of prolonged stillstand (or equilibrium) in the position of the margin of the ice-sheet during its overall decay that was completed in this area by about 16 000 years ago. During the glaciation meltwater became ponded at several times in the Vale of York due to ice blocking drainage via the Humber into the North Sea Basin and beyond. At times widespread proglacial lakes developed including Lake Humber and Lake Alne, the two layers of the glaciolacustrine deposits in the model (Alne and Hemingbrough formations) represent phases of these lakes.

Bedrock geology

The bedrock in the area is undifferentiated Triassic Sherwood Sandstone comprising weakly cemented brown sandstones. It is a regionally significant aquifer in the Vale of York as elsewhere in the England and Wales.

Reference

FORD, J R, MATHERS, S J, ROYSE, K R, ALDISS, D T & MORGAN, D J R.  2010.  Scientific discovery and realisation through 3D geological modelling, with examples from the UK. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften.161/2 205–218.