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Km2

Material name: Km2
Synonyms: N/A
Material (geologic): Late Kimmeridgian (upper part of the so-called "Tabalcon limestones"?) flint.

Late Kimmeridgian Km2 flint
Foto: Jehanne Féblot-Augustins, 2005.

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Material description

Mode of occurrence: Large globular nodules (10x10x10cm to 15x15x10 cm).
Cortex: White, chalky with a powdery texture, thin (1 to 3 mm), transition sharp.
Colour: Outer portion light grey, centre dark grey (N7.5 to N5.5).
Pattern: Banding restricted to outer portion (2 to 3 cm wide) under the cortex, centre featureless.
Appearance: Homogeneous material, dull and opaque, smooth and fine-grained.
Structure: Convoluted bioturbation figures.
Texture: Mudstone/wackestone.
Matrix: Opaque.
Grains: 7.5 to 12.5 %, irregularly shaped, 100 to 200 µ, a few larger grains (500 to 1000 µ).
Grain composition: Rare foraminifera, abundant sponge spicules (monaxon and triaxon), Dasycladaceae algae (Campbelliella striata and Clypeina), numerous oncoliths, sea urchin radioles, a few serpulids, numerous Tubiphytes; rare iron 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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Glandieu
Locality: Saint-Benoît / Glandieu waterfall
Synonyms: Sampling site Bugey 41 after Féblot-Augustins
Geographical description: The site is located along the D10, a narrow road following the small Gland watercourse leading into the very south of the Bugey, between 2 cliffs. Material collected from the cliff, in situ.
Geographical co-ordinates: east/x 855,2
north/y 2079,3
(Lambert zone II, NTF)

This corresponds with
Lat. 45° 39' 58" N
Long. 005° 36' 43" E
(WGS84)

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 3232 E of the French Institut Géographique National.

Geology: According to the geological map, the substrate belongs to unit J7-8, consisting of the Tabalcon limestone formation of Late Kimmerdigian age.

Map of all sampled localities of Kimmeridgian flint in the Bugey (PDF, 427 KB, opens in new window).

Type of source: Primary.
Other types of flint: All material from this source is classified as being of the Km2-type.
  Split nodule of Km2 flint
Foto: Jehanne Féblot-Augustins, 2005
 
 


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Morestel
Locality: Morestel, France, Isère department
Synonyms: Sampling site Bugey 42 after Féblot-Augustins
Geographical description: As the site is deemed vulnerable to over-collecting, no further details are given. If you have any questions about the exact location of the source for scientific study, contact the author for further details
Geographical co-ordinates: east/x 845
north/y 2081
(Lambert zone II, NTF)

This corresponds roughly with
Lat. 45° 41' N
Long. 005° 28' E
(WGS84)

Co-ordinate precision: As indicated above, this small site has to be protected from heavy exploitation. The coordinates above are accurate enough to get an idea where this material occurs, but deliberately too inaccurate to find the site on a map or with a GPS-receiver.
Geology: According to the geological map, the substrate belongs to the Late Kimmeridgian Tabalcon formation (unit J7-8).

Map of all sampled localities of Kimmeridgian flint in the Bugey (PDF, 427 KB, opens in new window).

Type of source: Primary.
Other types of flint: Apart from the Km2 type, also both other known Kimmeridgian materials, Km1 and Km3, can be found here.

  Flake of Upper Jurassic flint
Foto: Jehanne Féblot-Augustins, 2005
 
Piece of Km2 chert
Foto: Jehanne Féblot-Augustins, 2005
 
 

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