Meneage
Encyclopedia
The Meneage mɨˈneɪɡ is a district in west Cornwall
, United Kingdom
. The nearest large towns are Falmouth
and Penryn
. (Note: the coordinates above are the approximate centre of The Meneage district.)
The meaning of the name Meneage is "Monkish (land)" and the probability is that in the post-Roman period the land was in the possession of a confederacy of small Celtic monasteries. These may have been founded by missionaries from Brittany. "The north-eastern half of the Lizard peninsula ... has, for the last 1000 years at least and probably for a considerable time longer, gone by the popular name of Meneage, pronounced Menāgue. This name, like Roseland, has no official significance."--Gilbert H. Doble.
The district is divided into four parishes and part of a fifth. From west to east these are Mawgan in Meneage
(part), St Martin in Meneage
, Manaccan
, St Anthony in Meneage
, and (south of the Helford River) St Keverne
.
The geology of the district is complex and is now better understood by geologists than it used to be. John Smith Flett
described the Lizard boundary zone and Meneage breccia like this in 1933: "A vast mass ... of Lizard schists, Ordovician, Silurian and Devonian (and possibly Carboniferous), driven northwards and broken up by the late Carboniferous Hercynian movements."
Meneage gives its name to the Meneage Formation, which underlies most of the area. It forms part of the Devonian
Gramscatho Group, the sedimentary sequence that lies structurally beneath the Lizard complex and is exposed along its northern boundary. The Meneage Formation is an olistostrome
, of mudstone
containing clasts of sedimentary, metamorphic and igneous rocks, which reaches up to 1500 m in thickness. The sedimentary clasts include blocks of Ordovician
quartzite
that reach up to 200 m in length. In the upper part, some of the volcanic rocks appear to be in place (not as clasts) and are dated as Upper Devonian from conodont
s in interbedded limestone
s. The sequence has been affected by very low grade metamorphism
in the pumpellyite
–actinolite
facies, with the development of the assemblage pumpellyite + actinolite + chlorite
+ sericite
+ albite
+ carbonate ± clinozoisite
± prehnite
in the basic volcanics. The alteration of the plagioclase feldspars to albite in these rocks has previously been explained as a result of metasomatism
at the time of formation, and the rocks have been referred to as spilite
s. Such early alteration is possible but most of the effects are now interpreted to be a result of regional metamorphism.
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
, United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. The nearest large towns are Falmouth
Falmouth, Cornwall
Falmouth is a town, civil parish and port on the River Fal on the south coast of Cornwall, England, United Kingdom. It has a total resident population of 21,635.Falmouth is the terminus of the A39, which begins some 200 miles away in Bath, Somerset....
and Penryn
Penryn, Cornwall
Penryn is a civil parish and town in Cornwall, England, United Kingdom. It is situated on the Penryn River about one mile northwest of Falmouth...
. (Note: the coordinates above are the approximate centre of The Meneage district.)
The meaning of the name Meneage is "Monkish (land)" and the probability is that in the post-Roman period the land was in the possession of a confederacy of small Celtic monasteries. These may have been founded by missionaries from Brittany. "The north-eastern half of the Lizard peninsula ... has, for the last 1000 years at least and probably for a considerable time longer, gone by the popular name of Meneage, pronounced Menāgue. This name, like Roseland, has no official significance."--Gilbert H. Doble.
The district is divided into four parishes and part of a fifth. From west to east these are Mawgan in Meneage
Mawgan-in-Meneage
Mawgan-in-Meneage is a civil parish in Cornwall, United Kingdom. It is situated in the Meneage district of The Lizard peninsula south of Helston in the former administrative district of Kerrier....
(part), St Martin in Meneage
St Martin-in-Meneage
St Martin-in-Meneage is a civil parish and village in the Meneage district of the Lizard Peninsula in Cornwall, United Kingdom.The village is five miles south-southeast of Helston....
, Manaccan
Manaccan
Manaccan is a civil parish and village on the Lizard peninsula in south Cornwall, England, United Kingdom. The village is situated approximately five miles south-southwest of Falmouth....
, St Anthony in Meneage
St Anthony-in-Meneage
St Anthony-in-Meneage is a coastal civil parish and village in Cornwall, United Kingdom. The parish is in the Meneage district of The Lizard peninsula...
, and (south of the Helford River) St Keverne
St Keverne
St Keverne is a civil parish and village on the Lizard Peninsula in Cornwall, United Kingdom.The Cornish Rebellion of 1497 started in St Keverne. The leader of the rebellion Michael An Gof was a blacksmith from St Keverne and is commemorated by a statue in the village...
.
- St Mawgan in Meneage. The church is dedicated to St Mauganus; St Martin's is a chapelry belonging to this parish. Part of the parish is not in the Meneage district.
- St Martin in Meneage. The church is dedicated to St Martin of ToursMartin of ToursMartin of Tours was a Bishop of Tours whose shrine became a famous stopping-point for pilgrims on the road to Santiago de Compostela. Around his name much legendary material accrued, and he has become one of the most familiar and recognizable Christian saints...
and is a chapelry of Mawgan in Meneage (right of sepulture was granted in 1385). The ancient estates of Barry Mylor and Mathiana adjoin the church and the two names indicate that in early times there were chapels of two Breton saints here. Of St Melor at Merther Mylor (Barry Mylor) and St Anou at Merther Anou; the modern forms being variously corrupted.
- Manaccan. Though St Manacca was recorded as the patron saint in 1308 it is probable that the name has the meaning of Monks' Church. The form of the dedication in use today is to St Manaccus and St Dunstan.
- St Anthony-in-Meneage. The village is at . The church is dedicated to St AnthonyAnthony the HermitAnthony the Hermit , also known as Antony of Lérins, is a Christian saint. Anthony was born in Italy in the late 5th century, and raised from the age of eight by his relative St. Severinus...
and is somewhat away from the village near Gillan Harbour.
- St Keverne. The monastery here remained in existence after the Norman Conquest but subsequently fell into the hands of a layman. The church is dedicated to St Akeveranus. In the parish is Lesneague which can be derived from Cornish lis (court) and manahec (monks' land) which would indicate that it was once the seat of a local chieftain.
Geology
John Smith Flett
Sir John Smith Flett KBE FRS was a Scottish geologist. He was elected a Fellow of the Royal Society in 1913, received the Bolitho Medal of the Royal Geological Society of Cornwall in 1917, made KBE in 1925 and won the Wollaston Medal in 1935.In the mid 1970s, the then new, glass-faced structure...
described the Lizard boundary zone and Meneage breccia like this in 1933: "A vast mass ... of Lizard schists, Ordovician, Silurian and Devonian (and possibly Carboniferous), driven northwards and broken up by the late Carboniferous Hercynian movements."
Meneage gives its name to the Meneage Formation, which underlies most of the area. It forms part of the Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
Gramscatho Group, the sedimentary sequence that lies structurally beneath the Lizard complex and is exposed along its northern boundary. The Meneage Formation is an olistostrome
Olistostrome
The term olistostrome is derived from olio - a dish of many ingredients or stew; a mixture of heterogeneous elements; hodgepodge. and stroma - a bed covering...
, of mudstone
Mudstone
Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...
containing clasts of sedimentary, metamorphic and igneous rocks, which reaches up to 1500 m in thickness. The sedimentary clasts include blocks of Ordovician
Ordovician
The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...
quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
that reach up to 200 m in length. In the upper part, some of the volcanic rocks appear to be in place (not as clasts) and are dated as Upper Devonian from conodont
Conodont
Conodonts are extinct chordates resembling eels, classified in the class Conodonta. For many years, they were known only from tooth-like microfossils now called conodont elements, found in isolation. Knowledge about soft tissues remains relatively sparse to this day...
s in interbedded limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
s. The sequence has been affected by very low grade metamorphism
Metamorphism
Metamorphism is the solid-state recrystallization of pre-existing rocks due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids. Mineralogical, chemical and crystallographic changes can occur during this process...
in the pumpellyite
Pumpellyite
Pumpellyite is a group of closely related sorosilicate minerals:*pumpellyite-: Ca2MgAl2[2|SiO4|Si2O7]·*pumpellyite-: Ca2Fe2+Al2[2|SiO4|Si2O7]·*pumpellyite-: Ca22[2|SiO4|Si2O7]·H2O...
–actinolite
Actinolite
Actinolite is an amphibole silicate mineral with the chemical formula .-Etymology:The name actinolite is derived from the Greek word aktis , meaning "beam" or "ray", because of the mineral's fibrous nature...
facies, with the development of the assemblage pumpellyite + actinolite + chlorite
Chlorite group
The chlorites are a group of phyllosilicate minerals. Chlorites can be described by the following four endmembers based on their chemistry via substitution of the following four elements in the silicate lattice; Mg, Fe, Ni, and Mn....
+ sericite
Sericite
Sericite is a fine grained mica, similar to muscovite, illite, or paragonite. Sericite is a common alteration mineral of orthoclase or plagioclase feldspars in areas that have been subjected to hydrothermal alteration typically associated with copper, tin, or other hydrothermal ore deposits...
+ albite
Albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. As such it represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula NaAlSi3O8. It is a tectosilicate. Its color is usually pure white, hence...
+ carbonate ± clinozoisite
Clinozoisite
Clinozoisite is a mineral, a complex sorosilicate of calcium and aluminium and is usually a grey green colour.Its formula is Ca2Al3[O|OH|SiO4|Si2O7]....
± prehnite
Prehnite
Prehnite is a phyllosilicate of calcium and aluminium with the formula: Ca2Al2. Limited Fe3+ substitutes for aluminium in the structure. Prehnite crystallizes in the orthorhombic crystal system, and most oftens forms as stalactitic or botryoidal aggregates, with only just the crests of small...
in the basic volcanics. The alteration of the plagioclase feldspars to albite in these rocks has previously been explained as a result of metasomatism
Metasomatism
Metasomatism is the chemical alteration of a rock by hydrothermal and other fluids.Metasomatism can occur via the action of hydrothermal fluids from an igneous or metamorphic source. In the igneous environment, metasomatism creates skarns, greisen, and may affect hornfels in the contact...
at the time of formation, and the rocks have been referred to as spilite
Spilite
Spilite is a fine-grained igneous rock, resulting particularly from alteration of oceanic basalt.The term was introduced into the geological literature by Alexandre Brongniart in 1827...
s. Such early alteration is possible but most of the effects are now interpreted to be a result of regional metamorphism.
Further reading
- Barton, R. M. (1964) "The Lizard boundary zone and Meneage breccia", in: An Introduction to the Geology of Cornwall. Truro: D. Bradford Barton; pp. 32-38 & map foll. p. 166