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Material name: CN8a
Synonyms: Silex Crétacé supérieur Nord - Sénonien (Campanien)
Material (geologic): Late Cretaceous (Campanian, Senonian) flint

Close view of wackestone-flint
Foto: Jehanne Féblot-Augustins, 2005.

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Material description

Mode of occurrence: A single large regular nodule.
Cortex: Thin (<1 mm), smooth and worn, transition gradual.
Colour: Pale brown, putty-coloured (10YR 6/3).
Pattern: Featureless.
Appearance: Homogeneous material, dull and opaque, dry and quite rough, medium-grained.
Structure: No particular structure.
Texture: Wackestone.
Matrix: Opaque.
Grains: 15 to 30 % depending on the areas, rounded and irregularly shaped, pale or stained yellow by iron oxides, well sorted (125 µ).
Grain composition: Numerous sponge spicules, an arthropod, very globose planktonic foraminifera, biserial benthic foraminifera; detrital quartz, irons oxides.
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: Jujurieux / Chenavel - Château 2, France, Ain department
Synonyms: Sampling site Bugey 66 after Féblot-Augustins
Geographical description: The material was collected along the GR 59 long-distance footpath near the castle of Chenavel, which lies between the hamlet of Chenavel and the N 84 road, overlooking the river Ain, between Poncin and Pont-d'Ain.
Geographical co-ordinates: east/x 835.95
north/y 2123.1
(Lambert zone II, NTF)

This corresponds roughly with
Lat. 46° 04' 00.9" N
Long. 005° 23' 13.4" E

Co-ordinate precision: The French coordinates of the national Lambert-grid were read from an detailed topographical map. We calculated the geographical coordinates by transforming those values on the WGS84 ellipsoid.

The location can be found on the 1:25 000 topographical map sheet 3130 E of the French Institut Géographique National.

Geology: The flint here occurs in clays-with-flints of various origins (Early and Late Cretacous), although the silex is clearly of Late Cretaceous (Senonian) age.

Map of all sampled localities of Late Cretaceous flint in the Bugey (PDF, 54 KB, opens in new window).

Type of source: Secondary.
Other types of flint: Two other Senonian flints might be found here: CN1a and CN8b.
  Small rolled nodule
Foto: Jehanne Féblot-Augustins, 2005
Freshly struc flake
Foto: Jehanne Féblot-Augustins, 2005


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