Material name: | Bj2 |
Synonyms: | N/A |
Material (geologic): | Middle Jurassic (Early to Middle Bajocian) flint/chert |
Foto: Jehanne Féblot-Augustins, 2005. |
Sampled sites:
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Mode of occurrence: | Joining nodules forming siliceous beds 6 cm thick. |
Cortex: | Rough, light reddish tan, 1 cm thick, transition sharp. |
Colour: | Dark (bluish) grey (N4). |
Pattern: | Laminations 2 to 4 mm thick, lighter hues alternating with darker tones. |
Appearance: | Homogeneous material, dull and opaque, rather rough and coarse-grained. |
Structure: | Laminated, corresponding to differences in colour and texture, irregular bands of more or less milky matrix (recrystallized as chalcedony); frequent micro-vugs. |
Texture: | Wackestone (milky zones) to packstone. |
Matrix: | Milky to more translucent. |
Grains: | 20 to 40 %, irregularly shaped, rounded, poorly sorted (100 to 400 µ, overall impression 3-400 µ). |
Grain composition: | Peloids, foraminifera showing as "ghosts" outlined by impurities, numerous monaxon or triaxon sponge spicules, thick-walled and recrystallized as chalcedony; abundant grains of 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. |
Locality: | Jujurieux / La Courbattière, France, Ain department |
Synonyms: | Sampling site Bugey 7 after Féblot-Augustins |
Geographical description: | The source is located on a wooded slope facing the hamlet of La Courbattière, approx. 1 km southeast of Jujurieux. |
Geographical co-ordinates: |
east/x 838.50 north/y 2119.3 (Lambert zone II, NTF)
This corresponds roughly with |
Co-ordinate precision: |
The coordinates given were taken from a large-scale map, and are within approx. 50 to 100 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, the suggested higher precision is given to avoid the introduction of a transformation error. The location can be found on the 1:25 000 topographical map sheet 3230 W of the French Institut Géographique National. |
Geology: |
According to the geological map, the substrate belongs to unit l9b-J1b (Early Aalenian and Early-Middle Bajocian). Map of all sampled localities of Bajocian flint in the Bugey (PDF, 190 KB, opens in new window). |
Type of source: | Primary. |
Other types of flint: | All flint from this source belongs to type Bj2, and is, up to now, the only occurrence of this type of material. |
Foto: Jehanne Féblot-Augustins, 2005 |
Last modified on: November 15, 2005 |
Contents primarily by: Jehanne Féblot-Augustins |
Comments to: |