Trenance Farm Cottages

Mullion, Helston, Cornwall

tel: 00 44 (0)1326 240 639

Holiday Cottages in Cornwall
Holiday Cottages in Cornwall
Holiday Cottages in Cornwall
 3 to 4 stars
 3 to 4 stars

Open all year

pets welcome

child friendly

GEOLOGICAL FAULT

Geology Map

Separates the Lizard platform from the Meneage

ERICA VAGANS

Countryside Code

An example of a tolerant plant found on outcrops of serpentinite is the cornish heather (Erica vagans, RDB) which in Great Britain is restricted to the Lizard and grows only on soils overlying serpentinite and gabbro.


What makes the Lizard so special and unique ?

The geology of the Lizard is perhaps the most spectacular aspect of this area, as parts of the peninsula are the remains of the ancient ocean floor formed almost 400 million years ago that were pushed up towards the surface, when the African plate collided with the Eurasian plate some 300 million years ago. The rocks on the Lizard complex represent a fragment or slice of continental and oceanic components that have been thrust faulted (obducted) over younger rocks.

As a result of plate collision the Lizard has two distinct areas separated by the Lizard Boundary Faultline (LBF), the Lizard Platform and the Meneage.

The Lizard Platform to the south of the fault line is the remains of the ocean floor that were pushed up to the surface resulting in dramatic cliffs with rugged foreshores and wild heathland. This area is also devoid of high landmarks as the landform is predominantly a flat surface at aproximately 120m above mean sea level. Due to the toxic nature of serpentine and resulting poor soils the area has a distinctive flora of slow growing plants. The most famous local plant is the rare Cornish Heather, (Erica Vegans), which flowers from mid summer till October, forming beautiful swathes of colour on the cliffs and heathlands.

In contrast to this, the Meneage (Cornish for "Land of The Monks"), the area north of the fault line that arcs around the peninsula, has been eroded into deep wooded valleys resulting in a place of lush rolling hills, fertile farmland, valleys and ancient woodland including the Helford River and Gillan Creek.

The western edge of the Lizard boundary fault is exposed in the cliffside at Polurrian Cove close to Trenance Farm. Each time you walk down to Polurrian Cove you walk over the local geological fault line. The eastern edge of the boundary fault line meets the coastline at Porthallow.


The Lizard Boundary Fault

Move your mouse over the labels on the map below for information about the geolgical features.
 Jangye-ryn

JANGYE-RYN

In the rocks at Jangye-ryn there are superb examples of folding and tension gash veins due to crustal shortening, faulting due to crustal extension and rare Devonian plant fossils. Sediments range from black shales, sandstones to mud or siltstones (turbidites), which were deposited in the Gramscatho Sedimentary Basin.
 Polurrian Cove

LIZARD BOUNDARY FAULT AT POLURRIAN COVE

The Lizard Boundary Fault crosses Polurrian Cove separating the flat Lizard platform to the south and the rolling Meneage to the north. The Lizard Boundary Fault is exposed in the cliffside with metapelites (continental provenance) on one side and hornblende schist which marks the start of the Lizard complex (oceanic rocks) on the other. This fault zone runs across the Lizard from Polurrian on the south-west to Porthallow on the north-eastern side of the peninsula.
 Polurrian Cove

LIZARD BOUNDARY FAULT AT POLURRIAN COVE

Geology on the Lizard - A French school trip from Brittany standing astride the fault line on Polurrian cove, the fault crossing the peninsula to Porthallow on the east side.
 Mullion Cove

MULLION COVE

Mullion Cove is a jewel of the Lizard Peninsula where a fault marks the contact between hornblende schist and serpentinite. Offshore lies Mullion Island where there are exposures of pillow lavas, cherts and limestones, that may form the upper part of ophiolite rock sequence.
 Predannack

PREDANNACK

The coastline along the edge of Predannack Downs consists of high dramatic cliffs which extend from Mullion Cove around the coast to the Lizard Point. Inland from the tops of the cliffs, the flat open expanse of the Lizard Platform devoid of hills or high points is clearly evident, only cut by valleys to the coastline such as the spectacular cleft of Gew-graze (Soapy Cove) between Vellan Head and Pigeon Ogo.
 Kynance Cove

KYNANCE COVE

Kynance Cove is one of the jewels of the Lizard Peninsula with a special beach known in geomorphological terms as a Tombolo, it connects Asparagus Island to the mainland. It is also famous for its serpentine rock, which is used to carve ornamental pieces which can be purchased from the specialised serpentine turner shops located in Lizard village.
 The Lizard

THE LIZARD

At the Lizard Head the geology changes from hornblende schist to mica schist and gneiss. Polpeor Cove, above the old lifeboat station, affords the best view of these exposures. The Man of War Gneiss are the oldest rocks on the Lizard representing a metamorphosed granite from the old super continent Gondwandas collision zone and are some 500 million years old.
 Coverack

Coverack

The Coverack area provides a rare opportunity to examine a geological section showing a transition from the oceanic mantle to the crust. Here ultrabasic rock of peridotite in the mantle section is to the south, moving north the rare transition rock type of troctolite is exposed, to eventually basic crustal rocks of gabbro, all cut by basic dykes.
 Blackhead

BLACKHEAD

The Lizard is devoid of strong topographic highs with the landform predominantly an old erosion surface at c.120m above mean low tide. Due to the toxic nature of serpentinite to vegetation the area has a distinctive flora of slow growing plants.
 Porthallow

PORTHALLOW

At Porthallow Cove The Lizard Boundary Fault is exposed on the south side of the cove where the Old Lizard Head Series schist is faulted against the Meneage Melange rocks or Roseland Breccia. Further south the schists are overthrust by serpentinized peridotites and gabbro.
 Helford

HELFORD

The Helford River area has a history extending back almost 400 million years. Its geology records events associated with the movement of past geological plates, the subsequent formation of the river, and its modification by dramatic rises and falls of sea level particularly during the climate changes of the Ice Age, creating a drowned river valley known as a ria.
 St Anthony

ST ANTHONY at GILLAN CREEK

St Anthony sits on Gillan Creek which is a small version of the main Helford river, with a wide range of habitats within a short distance, varying from semi-exposed rocky shore with a sandy bottom at the entrance, through to mud under overhanging trees at the head of the creek.

For those interested in the geology of the area further information may be found with the following links:
Introduction to Lizard geology by Exeter University:
The Lizard.pdf.
Porthleven to Polurrian.pdf.
Lizard geology by Cornwall Wildlife Trust:
Lizard Geology

Trenance Farmhouse Serpentine Industry

Most of us return from our holidays with a souvenir to remind us of the place we visited. Some people treat themselves to a locally made pair of shoes, handbag or an item of jewellery, while others prefer an ornamental object, such as a piece of glassware or sculpture. A popular and timeless souvenir from the Lizard Peninsula is something crafted from serpentine. The shops of the local serpentine workers may be found at Lizard village.

The most extensive rock type on the Lizard Peninsula is serpentine which, spanning 20 square miles, is the largest outcrop of such rock in mainland Britain. When Queen Victoria and Prince Albert visited the area in 1846, they were so struck by serpentine's unusual characteristics, that their ensuing royal patronage spawned an industry of architectural and decorative stone working that continues, albeit somewhat diminished, to this day.

Cornish Chough Cornish Chough Cornish Chough