European Cenozoic Rift System
Encyclopedia
The European Cenozoic Rift System (ECRIS) is an 1100 km long system of rift
s formed in the foreland
of the Alps
as the lithosphere
responded to the effects of the Alpine
and Pyrenean orogenies
. The system began to form during the Late Eocene
and parts, particularly the Upper and Lower Rhine Grabens, remain seismically active today and are responsible for most of the larger earthquake
s in Europe, north of the Alps.
to the North Sea
.
plain. The main phase of subsidence continued until the Late Oligocene
. The graben
is controlled by faults on its western side and has a fill of up to 2 km of Cenozoic
sediments.
, but resumed in the Late Miocene. The eastern margin of the basin was overridden by thrust fault
s from the Jura Mountains
, the leading edge of the alpine thin-skinned deformation
.
where the ECRIS branches. Rifting initiated here in the Oligocene but the northern and southern parts of the graben show distinct post-Oligocene histories. In the Miocene
the southern part of the graben became uplifted, while the northern part continued to subside into the Pleistocene
. Currently the Upper Rhine Graben is thought to be experiencing dextral strike-slip reactivation.
. To the southeast the dominant faults are SW-dipping, while to the northwest they become NE-dipping, in both cases giving it a half-graben geometry. Rifting initiated during the Oligocene and continues to the present day.
. The largest volcanic centres were located to the southwest of the Limagne and Bresse Grabens, the Massif Central
, at the rift triple junction at the northern end of the Upper Rhine Graben, the Vogelsberg Mountains
and around the Eger Graben. The last recorded volcanic activity was a phreatomagmatic eruption
in the Chaîne des Puys
about 6,000 years ago.
, which had an epicenter
within the Upper Rhine Graben is the most damaging historical seismic event known from central Europe.
Rift
In geology, a rift or chasm is a place where the Earth's crust and lithosphere are being pulled apart and is an example of extensional tectonics....
s formed in the foreland
Foreland
Foreland is the easternmost point of the Isle of Wight. It is located three miles east of the town of Brading, and due south of the city of Portsmouth on the British mainland. It is characterised by a pub called the Crab and Lobster and various beach huts plus a beach cafe and a coast guard...
of the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
as the lithosphere
Lithosphere
The lithosphere is the rigid outermost shell of a rocky planet. On Earth, it comprises the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater.- Earth's lithosphere :...
responded to the effects of the Alpine
Alpine orogeny
The Alpine orogeny is an orogenic phase in the Late Mesozoic and Tertiary that formed the mountain ranges of the Alpide belt...
and Pyrenean orogenies
Geology of the Pyrenees
The Pyrenees form part of the huge alpine orogenic system. This 430 kilometre long, roughly east-west striking, intracontinental mountain chain divides France, Spain, and Andorra. It has an extended, polycyclic geological evolution dating back to the Precambrian...
. The system began to form during the Late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
and parts, particularly the Upper and Lower Rhine Grabens, remain seismically active today and are responsible for most of the larger earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
s in Europe, north of the Alps.
Extent
The ECRIS consists of a series of rifts and associated transfer faults extending from the MediterraneanMediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
to the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
.
Limagne Graben
This north-south trending rift structure formed in the middle Eocene creating a lake that is now the LimagneLimagne
The Limagne is large plain in the Auvergne region of France in the valley of the Allier river, on the edge of the Massif Central. It lies entirely within the département of Puy de Dôme...
plain. The main phase of subsidence continued until the Late Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
. The graben
Graben
In geology, a graben is a depressed block of land bordered by parallel faults. Graben is German for ditch. Graben is used for both the singular and plural....
is controlled by faults on its western side and has a fill of up to 2 km of Cenozoic
Cenozoic
The Cenozoic era is the current and most recent of the three Phanerozoic geological eras and covers the period from 65.5 mya to the present. The era began in the wake of the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and...
sediments.
Bresse Graben
The Bresse Graben lies to the east of the Limagne Graben. It initiated during the Eocene but the rifting stopped during the period from Late Oligocene to middle MioceneMiocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
, but resumed in the Late Miocene. The eastern margin of the basin was overridden by thrust fault
Thrust fault
A thrust fault is a type of fault, or break in the Earth's crust across which there has been relative movement, in which rocks of lower stratigraphic position are pushed up and over higher strata. They are often recognized because they place older rocks above younger...
s from the Jura Mountains
Jura mountains
The Jura Mountains are a small mountain range located north of the Alps, separating the Rhine and Rhone rivers and forming part of the watershed of each...
, the leading edge of the alpine thin-skinned deformation
Thin-skinned deformation
Thin-skinned deformation is a style of deformation in plate tectonics at a convergent boundary which occurs with shallow thrust faults that only involves cover rocks , and not deeper basement rocks....
.
Upper Rhine Graben
The Upper Rhine Graben extends from the northern edge of the Jura mountains in the south up to the triple junctionTriple junction
A triple junction is the point where the boundaries of three tectonic plates meet. At the triple junction a boundary will be one of 3 types - a ridge, trench or transform fault - and triple junctions can be described according to the types of plate margin that meet at them...
where the ECRIS branches. Rifting initiated here in the Oligocene but the northern and southern parts of the graben show distinct post-Oligocene histories. In the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
the southern part of the graben became uplifted, while the northern part continued to subside into the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
. Currently the Upper Rhine Graben is thought to be experiencing dextral strike-slip reactivation.
Lower Rhine Graben
The Lower Rhine Graben or Lower Rhine Embayment, trends NW-SE and continues offshore into structures within the southern North SeaNorth Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
. To the southeast the dominant faults are SW-dipping, while to the northwest they become NE-dipping, in both cases giving it a half-graben geometry. Rifting initiated during the Oligocene and continues to the present day.
Hessian Grabens
The Hessian grabens lie north of the Upper Rhine Graben and follow the same trend. There are two main rift structures, the Wetterau and Leine grabens. They were active during the Oligocene but are inactive now.Eger Graben
The easternmost part of the system, the Eger Graben shows two distinct phases of extension at the end of the Eocene and during the early Miocene. The first phase was oblique to the rift axis and led to the formation of en-echelon W-E trending fault sets, The second was orthogonal to the rift axis, leading to overprinting of the early W-E faults by later SW-NE trending faults.Origin
The rift system is thought to have formed in response to compression of the lithosphere in front of the zones of collision that formed the Alps and Pyrenees. The initial rift propagated northwards as the collision along the Alps intensified and the western part of France moved to the west.Volcanism
The development of the ECRIS was accompanied (and in some cases preceded) by volcanic activity over large parts of the rift system that persisted into the QuaternaryQuaternary
The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
. The largest volcanic centres were located to the southwest of the Limagne and Bresse Grabens, the Massif Central
Massif Central (geology)
The Massif Central forms together with the Armorican Massif one of the two big basement massifs in France. Its geological evolution started in the late Neoproterozoic and continues to this day. It has been shaped mainly by the Caledonian orogeny and the Variscan orogeny. The Alpine orogeny has...
, at the rift triple junction at the northern end of the Upper Rhine Graben, the Vogelsberg Mountains
Vogelsberg Mountains
The Vogelsberg Mountains are a group duct of ancient volcanic activity and are separated from the Rhön Mountains by the Fulda River and its valley....
and around the Eger Graben. The last recorded volcanic activity was a phreatomagmatic eruption
Phreatomagmatic eruption
Phreatomagmatic eruptions are defined as juvenile forming eruptions as a result of interaction between water and magma. They are different from magmatic and phreatic eruptions. The products of phreatomagmatic eruptions contain juvenile clasts, unlike phreatic eruptions, and are the result of...
in the Chaîne des Puys
Chaîne des Puys
The Chaîne des Puys is a north-south oriented chain of cinder cones, lava domes, and maars in the Massif Central of France. The chain is about 40 km long, and the identified volcanic features include 48 cinder cones, eight lava domes, and 15 maars and explosion craters. Its highest point is...
about 6,000 years ago.
Seismicity
Most seismic activity within the ECRIS is confined to the Upper and Lower Rhine Grabens. The 1356 Basel earthquake1356 Basel earthquake
The Basel earthquake of 18 October 1356 is the most significant seismological event to have occurred in Central Europe in recorded history and may have had a Mw magnitude as strong as 7.1....
, which had an epicenter
Epicenter
The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...
within the Upper Rhine Graben is the most damaging historical seismic event known from central Europe.