Leeds Geological Association

Local Geology

Related: Local geology  Fossils  The Leeds hippo  Geology and Scenery  Geology and Man 


Geological Map of the Leeds Area

Rocks belonging to the Carboniferous and Permian Periods make up the area around Leeds.

Carboniferous rocks underlie most of the area and the oldest of these are the sandstones and shales of the Millstone Grit. The Coal Measures are predominantly a shale, mudstone and sandstone series with thin seatearths and coals. All these rocks have a general dip to the south and south-east.

In the east is a narrow strip of rocks of Permian age which rest unconforably on the Coal Measures. An impersistent layer of Basal Sands is found at the base of these Permian rocks. The main outcrop however is of Magnesian Limestone which, due to its gentle easterly dip and greater resistance to erosion than the rocks it rests on, forms a low, north-south ridge.

Rocks younger than these were deposited across the area but they have been removed by erosion. The youngest geological material is that left by the melting of ice over 10,000 years ago during the closing stages of the last Ice Age. This material, called till, is still soft and consists of sticky clay containing boulders and pebbles.



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