Follow the GeoTrail at Plymouth University

Discover the GeoTrail

Significant building and paving stones here at the University, North Hill and part of Plymouth City Centre have been discovered by Plymouth University BSc (Hons) Geology and BA (Hons) Graphic Communication with Typography students. They have developed learning trails as part of their team projects, and these concepts have been incorporated into a GeoTrail.

Eighteen locations on the University campus have been included in the GeoTrail and aims to explain and interpret the origins of the rocks; the dispositional environment and subsequent geological history.

The trail is aimed at non-geologists, so scientific terms and geology names are explained in detail.

The history

Early 20th Century buildings such as the Plymouth City Museum, the Central Library and the Scott Building on campus were built off local limestone and Dartmoor granite.

The campus buildings of the 1960's used large amounts of concrete usually made with crushed rock (aggregate) from local quarries. However recently, the more exotic building stone used for cladding modern buildings is imported from China and are hung on a steel 'skeleton'. In this case much less aggregate is used as the panels are made out of glass or metal.


Follow the GeoTrail

To act as a focal point for the GeoTrail, a landscape feature consisting of stone columns, representing significant rocks of South West England is in place.


Location 1 

Granite Pillars - Drake's Place Park colonnade

Source: The source of the granite is uncertain but was probably Merrivale or one of the other Dartmoor quarries. The colonnade used paired granite columns recycled from a former C17th market building. It was Grade II listed in 1954.  




Ammonite discs in the image of a fossil have been mounted, stating the country, geological formation and quarry location of where the rocks were found. Locations of the geo trail are as follows: 


Location 2 

Pink Calcite in fountain base - Drake's Place Park

Source: The exact source of this rock is not known but, given the age of the fountain, it was probably sourced locally, possibly from one of the limestone quarries to the East of Plymouth.              


Location 3 

Sherwell Centre - North Hill gate pillar – weathered Oolitic limestone

Source: The source of this stone is uncertain, but may have been quarried on Portland Bill.

If so, it is probably from the Jurassic period and was deposited as marine sediment about 150 Million years ago in a warm, shallow sea

Within the limestone veins of calcite or calcified burrows of worm-like animals have been more resistant to weathering and now stand out above the surface.


Location 4 

Sherwell Centre - North Hill pink granite columns

Source: This pink granite is not found in South West England, but may have been imported from the Channel Islands, where it was quarried in large volumes.

Use: Here the pink columns contrast with the grey Plymouth Limestone, giving awarmer feel to the entrance to this former church.


Location 5 

Sherwell Hall, Sherwell Lane

Source: Unknown local quarry

An outstanding limestone building block giving an insight into the variety of life in the warm shallow seas of the Devonian period about 370 Million years ago..

Visible fossils include:

  • small bivalves (shells composed of two hinged halves like a cockle)
  • several species of hard coral
  • stromatoporoid sponges

Location 6  

Portland Square B - Belemnite  

Source: Gundelsheimer Marmorwerk, Solnhofen, Bavaria, Germany

Jurassic Belemnites were fast swimmers and predatory hunters. They were cephalopods and probably looked like modern squids but had hard internal skeletons, composed of calcium carbonate. It is usually part of this skeleton, called a ‘guard’ which is all that is preserved.


Location 7  

Portland Square C - Ammonite  

Source: Gundelsheimer Marmorwerk, Solnhofen, Bavaria, Germany

Ammonites are extinct marine invertbrate animals which existed in various forms for about 340 million years and dominated the warm seas for much of the Mesozoic era. They varied in size from possibly 2.5m in diameter to just a few cms.


Location 8 

Portland Square Building  

Source: believed to be Portugal   Stone name: Guido Blue

A shelly limestone with abundant gastropods, bivalves, peloids



Location 9 

Nancy Astor Building - paving

Source: believed to be Portland Roach Bed, probably from Albion Quarries

A fine, homogenous Jurassic oolitic limestone (Ma145±) with a varied fossil assemblage


Location 10 

Portland Square Lane - 'rubble wall'

Source: Various rough stone

The wall was constructed of whatever material easily came to hand , mostly comprising rocks of SW England, including sandstones, mudstone, slate and Plymouth Limestone


Locations 11 and 12  

'Ashburton Marble' - Rolle Building - West Wall

Source:  Linhay Quarry, Ashburton - ancient sponges, corals and algal mats.

Devonian stromatoporoid sponges were so abundant that they formed small reefs, a bit like those found around tropical islands today, which corals then colonised. Stromatoporoids died out and coral reefs disappeared in the mass extinction at the end of the Devonian period.


Location 13  

De Lank Granite - Student's Union - Ventilation Block

Source:  DeLank quarries on Bodmin Moor

Use: This tough, course-grained igneous rock is one of the strongest building materials available. It was used to build the fourth Eddystone Lighthouse off Plymouth in 1759, Tower Bridge and more recently, the Diana memorial in Hyde Park


Location 14  

Reynolds Building - Plymouth Limestone, reconstituted Portland Stone with granite detailing

Source: Most of the quarries producing dimension stone at this time were to the East of the city, in Turnchapel, Oreston and Plymstock, but it is hard to identify exact sources for specific buildings.

Use:  Materials used in this building include Plymouth Limestone, local granite and crushed Portland stone set in a cement matrix. This was a cheaper alternative to using real Portland Stone.


Location 15 

Scott Building - New Extension - sawn facing stone 

Source: Linhay Quarry, Ashburton

Use: The original part of Scott Building together with many older buildings in Plymouth used limestone blocks with a 'rock face' finish, fashioned by stonemasons. More recent buildings often use cut blocks, which are then polished to remove saw marks. The extensions to the Scott Building are clad in facing slabs.

Location 16   


Roland Levinsky Building - slate cladding


Source:
  Cwt Y Bugail quarry, Blaenau Ffestiniog, North Wales (OS grid ref SH732455)

Deposited as a fine mud in calm water, then ‘lithified’ into a shale by pressure from subsequent layers and finally cleaved into a slate by tectonic forces. Age: new techniques now indicate a date of 396 Ma.


Location 17  

Plymouth City Museum   Devonian Limestone paving (370Ma)

Source: Local limestone quarry

Use: Used here for paving, the Devonian Limestone varies in composition and colour due to different concentrations of iron and other minerals, Note how Plymouth limestone of alternating colours has been used to create an attractive pavement surface with pink-white banding in the lighter slabs.

 


Location 18 

 Plymouth City Museum & Art Gallery - entrance portal


Sources: local granite, limestone and cream- coloured Portland stone used for architectural effect