The Upper Rhine Plain, Rhine Rift Valley
or Upper Rhine Graben
(
German: ''Oberrheinische Tiefebene'', ''Oberrheinisches Tiefland'' or ''Oberrheingraben'',
French: ''Vallée du Rhin'') is a major
rift
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...
, about and on average , between
Basel
Basel ( ; ), also known as Basle ( ), ; ; ; . is a city in northwestern Switzerland on the river Rhine (at the transition from the High Rhine, High to the Upper Rhine). Basel is Switzerland's List of cities in Switzerland, third-most-populo ...
in the south and the cities of
Frankfurt
Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the forela ...
/
Wiesbaden
Wiesbaden (; ) is the capital of the German state of Hesse, and the second-largest Hessian city after Frankfurt am Main. With around 283,000 inhabitants, it is List of cities in Germany by population, Germany's 24th-largest city. Wiesbaden form ...
in the north. Its southern section straddles the
France–Germany border
The international border between the modern states of France and Germany has a length of . The southern portion of the border, between Saint-Louis at the border with Switzerland and Lauterbourg, follows the River Rhine (Upper Rhine) in a so ...
. It forms part of the
European Cenozoic Rift System, which extends across
Central Europe
Central Europe is a geographical region of Europe between Eastern Europe, Eastern, Southern Europe, Southern, Western Europe, Western and Northern Europe, Northern Europe. Central Europe is known for its cultural diversity; however, countries in ...
. The Upper Rhine Graben formed during the
Oligocene
The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
, as a response to the evolution of the
Alps
The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia.
...
to the south. It remains active to the present day. Today, the Rhine Rift Valley forms a downfaulted trough through which the river
Rhine
The Rhine ( ) is one of the List of rivers of Europe, major rivers in Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Austria–Swit ...
flows.
Formation
The Upper Rhine Plain was formed during the Early
Cenozoic
The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...
era, during the Late
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
epoch. At this time, the
Alpine Orogeny
The Alpine orogeny, sometimes referred to as the Alpide orogeny, is an orogenic phase in the Late Mesozoic and the current Cenozoic which has formed the mountain ranges of the Alpide belt.
Cause
The Alpine orogeny was caused by the African c ...
, the major mountain building event that was to produce the
Alps
The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia.
...
, was in its early stages. The Alps were formed because the continents of Europe and Africa collided. It is thought that because the collision was irregular, the initial contact between the two continents resulted in the formation of dilational (extensional) structures in the
foreland basin
A foreland basin is a structural basin that develops adjacent and parallel to a mountain belt. Foreland basins form because the immense mass created by crustal thickening associated with the evolution of a mountain belt causes the lithospher ...
to the north of the Alps. The result was substantial crustal thinning, forming a major extensional ''
graben
In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults.
Etymology
''Graben'' is a loan word from German language, German, meaning 'ditch' or 't ...
'' and causing isolated volcanic activity. The stretch factor is estimated to be ~2.
Rift flank uplift
To both the east and west of the Rhine Plain, two major hill ranges have formed that run the length of the basin. To the west, in France, these hills are known as the
Vosges mountain range and in the east, in Germany, the hills comprise the
Black Forest
The Black Forest ( ) is a large forested mountain range in the States of Germany, state of Baden-Württemberg in southwest Germany, bounded by the Rhine Valley to the west and south and close to the borders with France and Switzerland. It is th ...
. These ranges exhume the same types of rocks in their cores, including deep crustal
gneiss
Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under p ...
. Both ranges correspond to uplifts of more than 2,500 metres, much of which has since been eroded. This uplift has occurred because of the isostatic response associated with the formation of an extensional basin. As a consequence, the highest mountains exist immediately adjacent to the margin of the basin, and become increasingly low outwards. The boundaries between the hill ranges and the Rhine Graben are defined by major,
normal fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
zones.
The northern section of the Rhine Plain is equally framed by somewhat lower mountain ranges, the
Palatinate Forest
The Palatinate Forest (; ), sometimes also called the Palatine Forest, is a List of landscapes in Rhineland-Palatinate, low-mountain region in southwestern Germany, located in the Palatinate (region), Palatinate in the state of Rhineland-Palatina ...
on the western and the
Odenwald
The Odenwald () is a low mountain range in the Germany, German states of Hesse, Bavaria and Baden-Württemberg.
Location
The Odenwald is located between the Upper Rhine Plain with the Bergstraße Route, Bergstraße and the ''Hessisches Ried' ...
on the eastern side.
Volcanic activity

The extension induced by the formation of the Alps was sufficient to thin the crust and provide suitable dilational conduits for magmatic and volcanic activity to occur. This resulted in the emplacement of
mafic
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...
dykes, which follow the general structural trend of the extensional faults. In addition, isolated volcanoes such as the Kaiserstuhl were formed.
The Kaiserstuhl volcano
The
Kaiserstuhl (literally "Emperor's Chair") is a cluster of volcanic hills to the northwest of Freiburg, within the Rhine Graben. The highest point of this small, isolated volcanic centre is the
Totenkopf (557 metres). Volcanic activity was most prevalent in the
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 ...
epoch, some 15 million years ago. Today, the Kaiserstuhl volcano is extinct.
Seismic activity
In 1356, the
Basel earthquake occurred in the Rhine Plain. It was perhaps the most destructive earthquake ever in
northwest Europe
Northwestern Europe, or Northwest Europe, is a loosely defined subregion of Europe, overlapping Northern Europe, Northern and Western Europe. The term is used in geographic, history, and military contexts.
Geographic definitions
Geography, Geo ...
, destroying the city of
Basel
Basel ( ; ), also known as Basle ( ), ; ; ; . is a city in northwestern Switzerland on the river Rhine (at the transition from the High Rhine, High to the Upper Rhine). Basel is Switzerland's List of cities in Switzerland, third-most-populo ...
and flattening buildings as far as 200 km away. It was the most significant historic seismological event to have occurred in Central Europe. Its epicenter was between
Waldkirch and
St. Peter in
Breisgau-Hochschwarzwald
Breisgau-Hochschwarzwald () is a (district) in the southwest of Baden-Württemberg, Germany. Fifty towns and municipalities with 133 settlements lie within the district. The district itself belongs to the region of Freiburg with the region of Sou ...
. However, it remains disputed whether the fault that ruptured to cause this earthquake was part of the Rhine Valley extensional system, or simply one of the many
thrust faults that make up the
Alps
The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia.
...
to the south. Doubts have been raised over the adequacy of the seismic evaluation and design of the
Fessenheim Nuclear Power Plant, built in the Rhine Plain close to the faults.
[Centrale Nucléaire de Fessenheim : appréciation du risque sismique]
RÉSONANCE Ingénieurs-Conseils SA, published 2007-09-05, accessed 2011-03-30
Upper Rhine aquifer
Located below the plain, the Upper Rhine
aquifer
An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...
– one of the largest in Europe – holds an estimated of fresh water and supplies some 3 million people in France and Germany, supplying 75% of their drinking water and 50% of the water used by industry.
[Assessing the benefits of different groundwater protection levels: results and lessons learnt from a contingent valuation survey in the Upper Rhine valley aquifer, France]
S Aulong & JD Rinaudo, IWRA 13th World Water Congress, published 2008-01-09, accessed 2011-04-13 Since the 1970s it has suffered increasingly serious pollution from
nitrate
Nitrate is a polyatomic ion with the chemical formula . salt (chemistry), Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are solubility, soluble in wa ...
s,
pesticide
Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...
s,
chloride
The term chloride refers to a compound or molecule that contains either a chlorine anion (), which is a negatively charged chlorine atom, or a non-charged chlorine atom covalently bonded to the rest of the molecule by a single bond (). The pr ...
and
VOCs.
Research

A collaboration of 25 universities and government agencies have been researching seismic hazards, neotectonics, and water management of the Quaternary Graben fill. The research focuses on four themes:
* "
Neotectonics and Seismic Hazard (identification of zones of on-going deformation, current stress regime, earthquake location & frequency, hazard assessment)"
* "Modeling of Hydro systems (modeling of Plio-Quaternary hydro systems of the Upper Rhine Graben and transfer time of pollutants within them)"
* "Structure and Evolution (reassessment of structural evolution of the Upper Rhine Graben and implications for its neotectonic deformation, fault reactivation, crustal rheology and earthquake activity)"
* "Dynamic Modeling (multi scale dynamic modeling of the past and present deformation of the Rhine Graben area)"
See also
*
Ried
References
External links
EUCOR-URGENTFranco-German-Swiss Conference of the Upper Rhine
{{Coord, 48.9650, N, 8.2340, E, source:wikidata-and-enwiki-cat-tree_region:DE, display=title
Rifts and grabens
Natural regions of the South German Scarplands
Geology of Germany
Geology of France
Landforms of Metropolitan France
Landforms of Germany
Aquifers
Rhineland
Regions of Baden-Württemberg
Upper Rhine
Cenozoic rifts and grabens
Depressions of Europe
France–Germany border