The Chaîne de l'Épine, in the department of

Savoie Savoie (; Arpitan: ''Savouè'' or ''Savouè-d'Avâl''; English: ''Savoy'' ) is a department in the Auvergne-Rhône-Alpes region, Southeastern France. Located in the French Alps, its prefecture is Chambéry. In 2019, Savoie had a population ...

in southeast France, is a long ridge of the Jura Mountains that runs north–south along the east side of the

Lac d'Aiguebelette Lac d'Aiguebelette is a natural lake in the commune of Aiguebelette-le-Lac, within the department of Savoie, France. Geography Description With a surface area of 5.45 km2 and a depth of 71 meters it is one of the largest natural lakes of F ...

, from the Col de l'Épine west of

Chambéry Chambéry (, , ; Arpitan: ''Chambèri'') is the prefecture of the Savoie department in the Auvergne-Rhône-Alpes region of eastern France. The population of the commune of Chambéry was 58,917 as of 2019, while the population of the Chamb ...

as far as the western edge of the

Chartreuse Mountains The Chartreuse Mountains (french: massif de la Chartreuse ) are a mountain range in southeastern France, stretching from the city of Grenoble in the south to the Lac du Bourget in the north. They are part of the French Prealps, which continu ...

, near the commune of Les Échelles. To the north, the ridge becomes the Mont du Chat ridge along the western shore of the

Lac du Bourget Lac du Bourget (; English Lake Bourget), also locally known as Lac Gris (; en, Grey Lake) or Lac d'Aix (), is a lake at the southernmost end of the Jura Mountains in the department of Savoie, France. It is the deepest lake located entirely wit ...

. At the southern end, the ridge terminates at the Guiers River.

Etymology

There are two explanations for the origin of the name "Chaîne de l'Épine". One traces "l'Épine" as a reference to a thorn from

Christ Jesus, likely from he, יֵשׁוּעַ, translit=Yēšūaʿ, label=Hebrew/Aramaic ( AD 30 or 33), also referred to as Jesus Christ or Jesus of Nazareth (among other names and titles), was a first-century Jewish preacher and religious ...

crown of thorns According to the New Testament, a woven crown of thorns ( or grc, ἀκάνθινος στέφανος, akanthinos stephanos, label=none) was placed on the head of Jesus during the events leading up to his crucifixion. It was one of the in ...

that Guillaume de Montbel brought back with him on his return from the Seventh Crusade in 1254. Montbel built the Château de l'Épine on the ridge above Nances and placed the holy thorn relic in the castle's chapel. In time, the chapel became such an important pilgrimage site that the name "l'Épine" was given to the whole mountain. The second explanation sees the Celtic god ''Pen'' as the source for both the name of the Chaîne de l'Épine ridge and the commune of Lépin-le-Lac to its west.

Geography

Topography

The Chaîne de l'Épine and the Mont du Chat separate the

(to the east and north) from the

(to the west and south). The highest point is Mont Grelle (also spelled

Mont Grêle Mont may refer to: Places * Mont., an abbreviation for Montana, a U.S. state * Mont, Belgium (disambiguation), several places in Belgium * Mont, Hautes-Pyrénées, a commune in France * Mont, Pyrénées-Atlantiques, a commune in France * Mont, Sa� ...

) at an elevation of . Another notable peak is Gratte-Cul at the northern end of Mont Grelle.

Geology

The Chaîne de l'Épine is an

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...

, part of the "upper ridge" geological structure of the Jura Mountains. Situated between two

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

molasse basins, the ridge is chiefly composed of limestones from the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

and

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

periods. The western escarpment, between the Col de l'Épine and the Col de Saint-Michel, is composed of limestones from the

Kimmeridgian In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxford ...

and Oxfordian formations, with

scree Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. Talus deposits typically ...

at the base. The portion south of the Col de Saint-Michel consists mainly of scree with a Jurassic limestone ridge. The east escarpment, is composed of

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretace ...

marls and

marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphose ...

s, with scree and Cretaceous limestone at the base.Geological Map of France, from the website of the French government's Geological and Mineral Research Office. South of the Col de Saint-Michel pass, a change in the strike-slip fault deflects the ridge line to run northeast–southwest. Another slip fault crosses the ridge perpendicularly at the northern tip of the peak Gratte-Cul. The fold extends across the

Guiers The Guiers () is a river in the Isère and Savoie departments of eastern France. It is long. It rises in the Chartreuse Mountains. The part upstream from the confluence with the Guiers Vif The Guiers Vif (, literally ''live Guiers'') is a rive ...

river at Entre-deux-Guiers to join the Mont Tournier anticline and form the Grand-Ratz plateau above

Voreppe Voreppe () is a commune in the Isère department in southeastern France. It is part of the Grenoble urban unit (agglomeration).

Passes and tunnels

There are three principal passes across the ridge. A paved road (D916) runs over the Col de l'Épine. The two other passes, the Col du Crucifix and the Col Saint-Michel, overlook the

and are crossed by hiking trails. Some of these trails follow the routes of earlier

Roman Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *'' Epistle to the Romans'', shortened to ''Romans'', a lette ...

roads.

The ''Voie Sarde'' skirts the southern end of the ridge, near Saint-Christophe, northeast of Les Échelles. The ''Voie Sarde'' or Sardinian Way was originally part of the Roman

Via Agrippa ''Via Agrippa'', is any stretch of the network of Roman roads in Gaul that was built by Marcus Vipsanius Agrippa, to whom Octavian entrusted the reorganization of the Gauls. In all, the Romans built of roads in Gaul. Agrippa's project Agrippa's ...

road network. In 1670 the road was rebuilt by

Charles Emmanuel II, Duke of Savoy Charles Emmanuel II ( it, Carlo Emanuele II di Savoia); 20 June 1634 – 12 June 1675) was Duke of Savoy from 1638 to 1675 and under regency of his mother Christine of France until 1648. He was also Marquis of Saluzzo, Count of Aosta, Geneva, M ...

with the aim of connecting his western landholdings in Savoie to

Turin Turin ( , Piedmontese: ; it, Torino ) is a city and an important business and cultural centre in Northern Italy. It is the capital city of Piedmont and of the Metropolitan City of Turin, and was the first Italian capital from 1861 to 1865. The ...

, capital of the Duchy of Savoy. In 1720, following the acquisition of Sardinia in the 1718 Treaty of London, the duchy officially became the

Kingdom of Sardinia The Kingdom of Sardinia,The name of the state was originally Latin: , or when the kingdom was still considered to include Corsica. In Italian it is , in French , in Sardinian , and in Piedmontese . also referred to as the Kingdom of Savoy-S ...

, leading the road to become known colloquially as the ''Voie Sarde''. A century later,

Napoleon Napoleon Bonaparte ; it, Napoleone Bonaparte, ; co, Napulione Buonaparte. (born Napoleone Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napoleon I, was a French military commander and political leader who ...

judged this narrow route to be an impediment to his military campaigns. After 13 years of construction (1804–17), the ''Tunnel de la Grotte'' bypassed the ''Voie Sarde'' route. The tunnel was nearly long and wide and high, sufficient for two laden wagons to pass. The English artist J. M. W. Turner sketched views of both the ''Voie Sarde'' and the new tunnel in 1819. The modern-day

Route nationale 6 The Route nationale 6 is a trunk road ( nationale) in France between Paris and the frontier with Italy in the Alps. Reclassification The RN 6 runs parallel for a long portion of its route to the A 6 autoroute. As a result, portions of the roa ...

uses this tunnel to cross the southern end of the Chaîne de l'Épine ridge. There are tunnels through the main bulk of the ridge in two places, both named Tunnel de l'Épine. The

A43 autoroute The A43 autoroute, also known as ''l'autoroute alpine'' and ''l'autoroute de la Maurienne'', is a motorway in France. Travelling through the French Alps, the road connects the city of Lyon with the Tunnel du Fréjus, near Modane, which passes the ...

runs through a pair of parallel tunnels under the Col de l'Épine. The northern tunnel is long and was completed in 1974; the southern tunnel is long and was completed in 1991. This is the 14th-longest road tunnel crossing in France. About to the south is a single-track tunnel completed in 1884 for the Saint-André-le-Gaz–

railway line. This tunnel begins east of the station of

Aiguebelette-le-Lac Aiguebelette-le-Lac () is a commune and village in the Savoie department in the Auvergne-Rhône-Alpes region in south-eastern France. In 2016, it had a population of 249 people. It is named after and lies near the southeastern shore of Lac d'Aig ...

and runs under the ridge, south of the Col Saint-Michel, to emerge just west of the now-closed Saint-Cassin-la-Cascade station, in the valley of the

Hyères Hyères (), Provençal Occitan: ''Ieras'' in classical norm, or ''Iero'' in Mistralian norm) is a commune in the Var department in the Provence-Alpes-Côte d'Azur region in southeastern France. The old town lies from the sea clustered arou ...

river, a left tributary of the

Rhône The Rhône ( , ; wae, Rotten ; frp, Rôno ; oc, Ròse ) is a major river in France and Switzerland, rising in the Alps and flowing west and south through Lake Geneva and southeastern France before discharging into the Mediterranean Sea. At Ar ...

Tour de France

The Col de l'Épine is a popular route for cyclists. The pass formed part of the route for the

Tour de France The Tour de France () is an annual men's multiple-stage bicycle race primarily held in France, while also occasionally passing through nearby countries. Like the other Grand Tours (the Giro d'Italia and the Vuelta a España), it consists ...

in 1947, 1965 and

1968 The year was highlighted by protests and other unrests that occurred worldwide. Events January–February * January 5 – " Prague Spring": Alexander Dubček is chosen as leader of the Communist Party of Czechoslovakia. * Janu ...

when it was classed at a Category 2 climb. The winners of these three climbs were:Le col de l'Épine dans le Tour de France
/ref> * 1947: * 1965: *

: Although the 2013 Tour de France included a section over the Col de l'Épine as part of Stage 19, this was a different pass of the same name, northeast of

Faverges Faverges (; frp, Favèrges) is a former commune located in Haute-Savoie department situated in the Auvergne-Rhône-Alpes region (south-east of France). On 1 January 2016, it was merged into the new commune of Faverges-Seythenex.

Panorama

References

External links

Geological analysis of the Lac d'Aiguebelette and Chaîne de l'Épine, on the site Geol-Alp

{{DEFAULTSORT:Epine Landforms of Metropolitan France Mountain passes of Auvergne-Rhône-Alpes Landforms of Auvergne-Rhône-Alpes Ridges of Europe Landforms of Savoie