A Taste of the Peak District

Accommodation, activities and attractions of the Peak District of the UK

 Site Map >> Home >> Peak District General Information >> Peak District Geology (overview)

The Peak District was the first region in the UK to be designated as a National Park. Read a little about the geology of the area on this page. The rocks are mainly Carboniferous in age and include examples of coal measures, Millstone Grit, Yoredale series and Carboniferous limestone groups. There are also basaltic lava flows and a vent agglomerate. Overall the thickness of the Carboniferous in the Peak is about 3000m.

Home Accommodation Towns Attractions Climbing Cycling Walking Peak Views General info Mining Geology Archaeology Contact

Click here for the official Peak District National Park web site.

Click here for the Open University Geology East Midlands branch web site.

Overview of Peak District Geology

The nature of the Peak District rocks has been determined by the presence of St. George’s Land (later the Wales-Brabant ridge) and a land mass to the north, where Scotland now exists.

To the south of Britain lay a major ocean trough, created by the collision of two of the Earth’s plates. This would later be responsible for the folding and faulting of the rocks of the UK.

The collision gave rise to the Variscan (Armenian) orogeny which continued throughout the Devonian and Carboniferous systems. It was during this orogeny that the Derbyshire dome and the Goyt syncline were formed.

Many faults have been affected by mineralisation giving rise to veins and rakes (vertical mineral veins). Joints in the limestone have also been mineralised. The joints are fissures created in the still consolidating rocks as overlying rocks were eroded and removed, reducing the load and therefore the pressure.

A number of the faults and folds affect all of the Peak District rocks and must therefore be later. These are in no way aligned and thought to have been caused by movements of the basement rocks. The basement is imagined to have been made up of a complex system of blocks of older rocks, as these moved under pressure, the overlying rocks were disturbed.

It has been postulated by extrapolation of the existing rocks, that the Derbyshire dome would have been around 3000m above the sea level of the time. Currently the high point lies on the Kinder Scout plateau at 636m.

St. George’s Land persisted throughout the Lower Carboniferous and gave rise to a shallow shelf sea of varying depth in the region of Derbyshire. The edge of the shelf is represented at Castleton and in the Hartington/Earl Sterndale area but is not observed elsewhere.

These areas are unique in that they offer us a view of the actual topography of the sea floor as it existed at that time.

Evidence from fossils shows that the UK was placed close to the equator during Carboniferous times - no seasonal growth is seen. This is further backed up by palaeomagnetic evidence, placing the UK no more than 30 degrees north or south of the equator at most.

There was a deep basin to the north of the shelf at Castleton. This was filled during the upper Carboniferous with shales (claystones) and coarse sandstones of deltaic origin. There are occasional marine bands in the deltaic sediments and also some turbidites, showing the front of the delta was not stabilised. These sediments were derived from a mountain range to the north.

The basin was subsiding at about the same rate as sedimentation was occurring. This subsidence was caused by the plate boundary to the south of the UK. Some of the shallow water limestones show weathering surfaces.

Many of the fossils in the Peak District are broken up, indicative of a relatively high energy environment overall. This damage to the fossils could have been a result of storm damage or strong currents transporting the remains from where the original organisms died. There are a few locations where undamaged, well preserved fossils occur.

The reef limestones of the Peak District lack the characteristics of modern reefs and are best described as ‘Mud Mounds’. These mounds are held together by (cyano)bacterial or algal activity. Where they are located on areas where the sea bed was flat, they are referred to as reef knolls e.g. High Tor at Matlock Bath, but where they occur at the edge of the shelf, they are called apron reefs e.g. the Castleton area.

There was a little vulcanism in the Peak District during the Lower Carboniferous which gave rise to basalts and tuffs, interbedded with limestones. Some of these flows can be seen at Tideswell dale (where spheroidal weathering is seen in a small quarry) on the high ground to the north of Matlock Bath and in the Castleton area, notably Cave Dale and Calton Hill. The lava of Calton Hill was quarried for a number of years in the first half of the 20th century.

The Variscan Orogeny caused the rocks of the Peak District to be folded N-S into a broad anticline. All of the rocks show faulting in places, as evidenced by the presence of slickenslides e.g. between Crow Chin and Cleft Buttress at Stanage Edge (rocks to the left hand side of the gully, looking upwards. The anticline has subsidiary folds on the limbs such as the Goyt Syncline and Todd Brook Anticline.

Search this site powered by FreeFind

 

We can accept no responsibility for your wellbeing if you visit any of the sites mentioned on this web site, they are included only as information. You should ensure that the necessary permissions are sought when entering private property and also take appropriate action to ensure your personal safety.