Satellite image showing the geography of the Upper Rhine Graben and the rift flanks of Vosges, France, and the Black Forest, Germany.

The Upper Rhine Graben is a major extensional rift system in Central Europe, straddling the border between France and Germany. In Geology, a rift is a place where the Earth 's crust and Lithosphere are being pulled apart and is an example of Extensional tectonics This article is about the country For a topic outline on this subject see List of basic France topics. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. It formed during the Cenozoic as a response to the evolution of the Alps to the south. The Cenozoic (also Caenozoic or Cainozoic) Era (ˌsiːnəˈzoʊɪk/ /ˌsɛn- (meaning "new life" ( Greek ( kainos) "new" Today, the Rhine Graben forms a basin through which the Rhine River flows and is bounded to the east by the Vosges mountain range, in France, and to the west by the Black Forest in western Germany. The Rhine (Rhein Rijn Rhin Reno Rain Rhenus is one of the longest and most important Rivers in Europe at 1320 kilometres (820 mi with an average discharge The Vosges (voːʒ or Vosges Mountains are a Mountain range in eastern France, stretching along the west side of the Rhine valley For the suburb of Adelaide, please see Black Forest South Australia; for the CDP in Colorado, please see Black Forest Colorado.

Formation

Schematic cross-section of the Rhine Graben.

The Upper Rhine Graben initiated during the Early Cenozoic era, during the Late Eocene epoch. The Cenozoic (also Caenozoic or Cainozoic) Era (ˌsiːnəˈzoʊɪk/ /ˌsɛn- (meaning "new life" ( Greek ( kainos) "new" The Eocene epoch (558 ± 02 - 339 ± 01 Ma) is a major division of the Geologic timescale and the second epoch of the Palaeogene period in At this time, the Alpine Orogeny, the major mountain building event that was to produce the Alps, was in its early stages. The Alpine orogeny (sometimes also called Alpide orogeny) is an orogenic phase in the Tertiary that formed the mountain ranges of the Alpide belt 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 to the north of the Alps^[1]. foreland basin is a depression that develops adjacent and parallel to a mountain belt The result was substantial crustal thinning, forming a major extensional graben and causing isolated volcanic activity. The stretch factor is estimated to be ~2.

Rift Flank Uplift

The Vosges mountain range, France, which formed due to rift-flank uplift on the margins of the Rhine Graben.

To both the east and west of the Rhine Graben, 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 Vosges (voːʒ or Vosges Mountains are a Mountain range in eastern France, stretching along the west side of the Rhine valley For the suburb of Adelaide, please see Black Forest South Australia; for the CDP in Colorado, please see Black Forest Colorado. These ranges exhume the same types of rocks in their cores, including deep crustal gneiss, and both ranges correspond to uplifts of more than 2,500 metres, much of which has since been eroded. Gneiss (ˈnaɪs is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from preexisting formations that were originally 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 zones. In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement

Volcanic Activity

The extension induced by the formation of the Alps was sufficient enough to thin the crust and provide suitable dilational conduits for magmatic and volcanic activity to occur. This resulted in the emplacement of mafic dykes which follow the general structural trend of the extensional faults. Mafic is an adjective describing a Silicate mineral or rock that is rich in magnesium and iron the term was derived by contracting "magnesium" and "ferric" 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 Kaiserstuhl (literally "emperor's chair" is a small group of hills of mostly volcanic origin in the Upper Rhine Valley in southwest Germany The highest point of this small, isolated volcanic centre is the Totenkopf (557 metres). Volcanic activity was most prevalent in the Miocene epoch, some 15 million years ago^[2]. The Miocene is a geological epoch of the Neogene period and extends from about 23 Today, the Kaiserstuhl volcano is extinct.

Seismic Activity

In 1356, the Basel earthquake occurred in the Rhine Graben. It was perhaps the most destructive earthquake ever to have occurred in northwest Europe, destroying the city of Basel and flattening buildings as far as 200 km away. North-West Europe is a term that refers to a northern area of Western Europe, although the exact area or countries it comprises varies "Basilia" redirects here For the Fly Genus, see Basilia (fly. However, it remains disputed whether the fault that ruptured to cause this earthquake was indeed part of the Rhine Graben extensional system, or simply one of the many thrust faults that make up the Alps to the south. A thrust fault is a type of fault, or break in the Earth's crust with resulting movement of each side against the other in which a lower stratigraphic position is pushed up

References