A HISTORY OF TOURAINE THROUGH ITS ROCKS
8 - IN NEOGENE

Simplified stratigraphical scale (the millions of years (MY) correspond to the period's beginning) :

4500 MY 540 MY 250 MY 65 MY
Eras Precambrian Paleozoic (primary era) Mesozoic (secondary era) Cenozoic (tertiary + quaternary eras)
Periods Paleogene Neogene Quaternary
65 MY 53 MY 33,7 MY 23,5 MY 5,3 MY 1,75 MY
Epochs Paleocene Eocene Oligocene Miocene Pliocene


The stages of Miocene :

23,5 MY 20,3 MY 15,8 MY 14,7 MY 11 MY 7,1 MY ==> 5,3 MY
Aquitanian Burdigalian Langhian Serravallian Tortonian Messinian


At the beginning of Neogene, a first marine episode reaches the west of Touraine...
In lower Miocene (Aquitanian), a first transgression of the sea invades Anjou. The west of Touraine is covered by lagoons where black clays settle. Above these clays, sands and marls with oysters are superposed and indicate a more marine environment.
During this time, an immense lake covers Beauce and deposits a calcareous mud.

Then Touraine is crossed by rivers coming from the Central Massif...
In Burdigalian, fluviatile sands settle in Touraine, as in close Sologne. It's necessary to visualize a river system very different from the current. Today, further to the quaternary glaciations, rivers are embanked in their bed. In Miocene, they spreaded on whole Touraine and crossed this one from south to north. Remains of mammals and reptiles were discovered in these sediments analogous to those deposited eastwards and known as "sands of Orléanais".


Sands of Orléanais - origin: Pontlevoy ("Département du Loir-et-Cher")

Then the sea of the faluns invades a big part of Touraine...
It is in medium Miocene (Langhian) that a marine gulf, in contact with the Atlantic Ocean and the English Channel, covered a vast region in the axis of current Val de Loire. This little deep sea deposited varied sediments named faluns: sandstone-like limestones, calcareous muds rich in bryozoans, sands with numerous fragments of shells. In a subtropical climate, the fauna was very varied (one thousand species): shells, corals, bryozoans, sea urchins, fishes, but also reptiles and mammals which populated the shores. Most of the found fossils date from the deposit of the faluns but some are reworked from underlying fluviatile sands or from sediments of the secondary era.


Falun in "savignéen" facies: sandstone-like limestone with Pecten subarcuatus, external and internal moulds of other bivalves, bryozoans and pebbles - origin: region of Savigné-sur-Lathan


Falun in "pontilévien" facies: sand with numerous fragments of shells - origin: Ferrière-Larçon

Several fossils are visible on the pages dedicated to the faluns: bivalves, gastropods, other invertebrates, fishes, reptiles, mammals and plants and the other remains.
See the map of the extension of the faluns sea. See also other comments on faluns.
See photos of one of the faluns quarries at Paulmy.

After the withdrawal of the faluns sea, new rivers deposit sands...
Further to an upheaval of the earth's crust, the sea of the faluns withdrew. It will return twice (upper Serravalian and upper Messinian) but will stop in Anjou, without reaching Touraine. During this time, continental sands, probably fluviatile origin, deposit, quite as those who had settled in Burdigalian before the sea of the faluns. These sands qualified "post-langhian" (because not dated exactly) are constituted by elements resulting from the erosion of the Central Massif, but also from local formations (faluns among others). Silicified fragments of wood are frequently found into these sands.


Silicified wood from post-langhian sands - origin: Charnizay (locality Limeray)


Post-langhian sands - origin: Neuillé-le-Lierre

See photos of the quarry of post-langhian sands at Neuillé-le-Lierre.

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