The Paris Basin () is one of the major geological regions of

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. It developed since the

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

over remnant uplands of the Variscan orogeny (Hercynian orogeny). The sedimentary basin, no longer a single drainage basin, is a large sag in the craton, bordered by the Armorican Massif to the west, the Ardennes-Brabant axis to the north, the Massif des Vosges to the east, and the Massif Central to the south.Duval, B.C., 1992, Villeperdue Field, In Giant Oil and Gas Fields of the Decade, 1978-1988, AAPG Memoir 54, Halbouty, M.T., editor, Tulsa: American Association of Petroleum Geologists,

Extent

The region usually regarded as the Paris Basin is rather smaller than the area formed by the geological structure. The former occupies the centre of the northern half of the country, excluding Eastern France. The latter extends from the hills just south of Calais to

Poitiers Poitiers is a city on the river Clain in west-central France. It is a commune in France, commune, the capital of the Vienne (department), Vienne department and the historical center of Poitou, Poitou Province. In 2021, it had a population of 9 ...

and from Caen to the brink of the middle Rhine Valley, east of Saarbrücken.

Geography

The landscape is one of very broad valleys (

flood plain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

s), modest watershed hills and well-drained plateaux of comparatively little altitude. In the south-east and east the plain of '' Champagne'' and the ''Seuil de Bourgogne'' (Threshold of Burgundy) differential erosion of the strata has left low scarps with the dip slopes towards the centre. The varying nature of the clays, limestones and chalk gives rise to the characteristics of the regions such as ''Champagne Humide'' (Damp Champagne), ''Champagne Pouilleuse'' (poor Champagne),''Pouilleuse'' means 'lousy' that is, 'infested with lice' but its meaning has broadened in use to include 'down and out'. This is a region of thin, chalk soils and little surface water. The epithet indicates the extreme poverty of the region when the name was acquired. the ''

Pays de Caux The Pays de Caux (, , literally ''Land of Caux'') is an area in Normandy occupying the greater part of the French '' département'' of Seine Maritime in Normandy. It is a chalk plateau to the north of the Seine Estuary and extending to the cl ...

'' and the '' Pays de Bray''. Due to the millions of years of later deposition, erosion and other changes since, five drainage basins today drain almost all of the Basin. These are two flowing north, the basins/specified parts of basins as follows: *upper Moselle and upper Meuse And three flowing west, the: * Seine basin, central Loire basin and Somme.

Structure

The Paris Basin is a

geological Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth s ...

basin of sedimentary rocks. It overlies geological strata folded by the Variscan orogeny. It forms a broad shallow bowl in which marine deposits from throughout periods from the

to the Pliocene were laid down. Their extent generally decreases with time. Based on analysis of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s recognized in the basin's strata during the 1820s and 1830s, the pioneering geologist Charles Lyell divided the Tertiary into three ages he named the Pliocene, 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 ...

and the

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 ...

. To the west, the strata folded by the Variscan rise below the more recent marine deposits in the hills of Brittany and, to the east, the Ardennes, Hunsrück and Vosges. To the south, the basin borders on the Massif Central and the Morvan. To the north, its early strata match those of the bed of the

English Channel The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busi ...

and south-eastern

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. Other boundaries lie on ridges in more recent deposits and scarps (escarpments). These include the Côte d'Or in the south-east (on an Alpine fault line) and, at a north end, the Hills of () Artois which overlie the margin of London-Brabant Massif.

Oil fields

Two notable oil fields are the Chaunoy Field, the other is the Villeperdue Field. They are centred at about 1850 metre depth.

References

Sources