Puy
Encyclopedia
Puy is a geological
term used locally in the Auvergne
, France
for a volcanic
hill
. The word derives from the Provencal
puech, meaning an isolated hill, coming from Latin podium, which has given also puig in Catalan and poggio in Italian.
Most of the puys of central France are small cinder cone
s, with or without associated lava
, whilst others are domes of trachytic
rock, like the domite of the Puy-de-Dôme
. The puys may be scattered as isolated hills, or, as is more usual, clustered together, sometimes in lines. The chain of puys in central France probably became extinct in late prehistoric time.
Other volcanic hills more or less like those of Auvergne are also known to geologists as puys; examples may be found in the Eifel
and in the small cones on the Bay of Naples, whilst the relics of puys denuded by erosion are numerous in the Swabian Alps of Württemberg
, as pointed out by W. Branco. Sir A. Geikie
has shown that the puy type of eruption was common in the British area in Carboniferous
and Permian
times, as abundantly attested in central Scotland
by remains of the old volcanoes, now generally reduced by denudation
to the mere neck, or volcanic vent, filled with tuff
and agglomerate
, or plugged with lava.
See Sir A. Geikie, Ancient Volcanoes of Great Britain (1897).
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
term used locally in the Auvergne
Auvergne (région)
Auvergne is one of the 27 administrative regions of France. It comprises the 4 departments of Allier, Puy de Dome, Cantal and Haute Loire.The current administrative region of Auvergne is larger than the historical province of Auvergne, and includes provinces and areas that historically were not...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
for a volcanic
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
hill
Hill
A hill is a landform that extends above the surrounding terrain. Hills often have a distinct summit, although in areas with scarp/dip topography a hill may refer to a particular section of flat terrain without a massive summit A hill is a landform that extends above the surrounding terrain. Hills...
. The word derives from the Provencal
Franco-Provençal language
Franco-Provençal , Arpitan, or Romand is a Romance language with several distinct dialects that form a linguistic sub-group separate from Langue d'Oïl and Langue d'Oc. The name Franco-Provençal was given to the language by G.I...
puech, meaning an isolated hill, coming from Latin podium, which has given also puig in Catalan and poggio in Italian.
Most of the puys of central France are small cinder cone
Cinder cone
According to the , Cinder Cone is the proper name of 1 cinder cone in Canada and 7 cinder cones in the United States:In Canada: Cinder Cone In the United States:...
s, with or without associated lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
, whilst others are domes of trachytic
Trachyte
Trachyte is an igneous volcanic rock with an aphanitic to porphyritic texture. The mineral assemblage consists of essential alkali feldspar; relatively minor plagioclase and quartz or a feldspathoid such as nepheline may also be present....
rock, like the domite of the Puy-de-Dôme
Puy-de-Dôme (mountain)
Puy de Dôme is a large lava dome and one of the youngest volcanoes in the Chaîne des Puys region of Massif Central in south-central France. This chain of volcanoes including numerous cinder cones, lava domes, and maars is located far from the edge of any tectonic plate. Puy de Dôme is located...
. The puys may be scattered as isolated hills, or, as is more usual, clustered together, sometimes in lines. The chain of puys in central France probably became extinct in late prehistoric time.
Other volcanic hills more or less like those of Auvergne are also known to geologists as puys; examples may be found in the Eifel
Eifel
The Eifel is a low mountain range in western Germany and eastern Belgium. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the south of the German-speaking Community of Belgium....
and in the small cones on the Bay of Naples, whilst the relics of puys denuded by erosion are numerous in the Swabian Alps of Württemberg
Württemberg
Württemberg , formerly known as Wirtemberg or Wurtemberg, is an area and a former state in southwestern Germany, including parts of the regions Swabia and Franconia....
, as pointed out by W. Branco. Sir A. Geikie
Archibald Geikie
Sir Archibald Geikie, OM, KCB, PRS, FRSE , was a Scottish geologist and writer.-Early life:Geikie was born in Edinburgh in 1835, the eldest son of musician and music critic James Stuart Geikie...
has shown that the puy type of eruption was common in the British area in Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
and Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
times, as abundantly attested in central Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
by remains of the old volcanoes, now generally reduced by denudation
Denudation
In geology, denudation is the long-term sum of processes that cause the wearing away of the earth’s surface leading to a reduction in elevation and relief of landforms and landscapes...
to the mere neck, or volcanic vent, filled with tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
and agglomerate
Agglomerate
Agglomerates are coarse accumulations of large blocks of volcanic material that contain at least 75% bombs...
, or plugged with lava.
See Sir A. Geikie, Ancient Volcanoes of Great Britain (1897).