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Material name: Bt5
Synonyms: N/A
Material (geologic): Middle Bathonian of the so-called "choin" [building stone] formations.

Detail of choin flint
Foto: Jehanne Féblot-Augustins, 2005.

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Material description

Mode of occurrence: Large discrete nodules occurring either within the limestone beds or at the boundary between two limestone beds.
Cortex: Rough, pale tan, thick (>1 cm), transition sharp.
Colour: Greyish white (10YR 8/1), white patina.
Pattern: Featureless.
Appearance: Homogeneous material, dull and opaque, rather rough, medium-grained.
Structure: No particular structure.
Texture: Mudstone/wackestone.
Matrix: Opaque, very white.
Grains: 10 to 12.5 % ( ?), very pale, high sphericity to irregularly shaped, 100 to 250 µ (flint difficult to read).
Grain composition: Short pelecypod fragments, rare foraminifera, Spatangus type sea urchin radioles.
Further information: Click here for the original French description (opens in a new window), or here for more information on the attributes used in the description (use your browser's "BACK"-button to return here).
Citing: Information on citing this page can be found here.

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Locality: Montalieu-Vercieu / Chalepont (quarry) , France, Isè department
Synonyms: Sampling site Bugey 26 after Féblot-Augustins
Geographical description: N/A
Geographical co-ordinates: east/x 839.5
north/y 2096.1
(Lambert zone II, NTF)

This corresponds roughly with
Lat. 45° 49' 23" N
Long. 005° 25' 09" E

Co-ordinate precision: The coordinates given were taken from a large-scale map, and are within approx. 50 metres of the actual spot.
The latitude/longitude coordinates are a direct transformation of these data on WGS84 and are accurate to the same level, so don't be deceived by the apparently high precision to the second.

The location can be found on the 1:25 000 topographical map sheet 3231 W of the French Institut Géographique National.

Geology: According to the geological map, the substrate belongs to unit J2, limestones of Middle Bathonian "choin" formation.

Map of all sampled localities of Bathonian flint in the Bugey (PDF, 195 KB, opens in new window).

Type of source: Primary.
Other types of flint: All material from this site belongs to the Bt5-type.
  Chert with parent-rock
Foto: Jehanne Féblot-Augustins, 2005
Very white flint
Foto: Jehanne Féblot-Augustins, 2005


Last modified on:
November 15, 2005
Contents primarily by:
Jehanne Féblot-Augustins
Comments to: