Foto: Jehanne Féblot-Augustins, 2005.
| Material name: | CN2a |
| Synonyms: | Silex Crétacé supérieur Nord - Sénonien (Campanien) |
| Material (geologic): | Campanian (Senonian, Late Cretaceous) flint |
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Foto: Jehanne Féblot-Augustins, 2005. |
| Mode of occurrence: | Irregular nodules or pebbles, generally small-sized, rare flattish regular cobbles. |
| Cortex: | Aspect varies depending on provenances; light brown, worn, smooth and thin (<1 mm) to rougher and thicker (2-3 mm); cream coloured, smooth, irregularly rolled with traces of impact; very thin alluvial neo-cortex, smooth to slightly pitted; transition always sharp. |
| Colour: | Pale brown to light brownish grey (10YR 6/3 to6/2) with greenish overtones (2.5Y 6/2). |
| Pattern: | Spotted (unreplaced matrix and 0.5 cm concentrations of elements). |
| Appearance: | Homogeneous material with a medium lustre, semi-opaque, moderately smooth, grain highly variable (coarse/medium to fine). |
| Structure: | Some samples display a fluidal arrangement of grains. |
| Texture: | Wackestone. |
| Matrix: | Opaque. |
| Grains: | 20 to 30%, very small pale rounded elements (50-80 µ), occasionally agglomerated, skeletal grains with high sphericity contained between 125 and 300 µ. |
| Grain composition: | Fragments of thin-walled sponge spicules, small benthic foraminifera, small globose planktonic foraminifera, rare small biserial foraminifera (Heterohelicidae), a few discrete spheres (200 µ), an acritarch; small ligneous debris. |
| 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: | Poncin / Breignes - Pierre-Feu 2, France, Ain department |
| Synonyms: | Sampling site Bugey 34 after Féblot-Augustins |
| Geographical description: | The source is located near a narrow road/path on a slight rise between the hamlets of Chenavel and Breignes, a bit over half a kilometre to the west of the latter, and somewhat more than 2 kilometres SSE of Poncin. |
| Geographical co-ordinates: |
east/x 838.2 north/y 2122.9 (Lambert zone II, NTF)
This corresponds with |
| Co-ordinate precision: |
The Lambert-coordinates given were read from a detailed topographical map, and are within 50 metres of the precise location. The latitude/longitude coordinates are a direct transformation of these data on WGS84 and have the same accuracy. They are given to the apparent high accuracy to prevent the introduction of a rounding-error. The location can be found on the 1:25 000 topographical map sheet 3230 W of the French Institut Géographique National. |
| Geology: |
The embedding materials are, according to the geological map, Late Miocene (Tortonian) continental sediments, belonging to the stratigraphic unit m2bC. The reworked flints themselves originate from Late Cretaceous (Campanian) limestones. Map of all sampled localities of Late Cretaceous flint in the Bugey (PDF, 54 KB, opens in new window). |
| Type of source: | Secondary. Redeposited Campanian flint from Miocene sediments. |
| Other types of flint: | Apart from the CN2a-type, other Late Cretaceous flints of the types CN1a and CN8c can be found here, as well as the Middle Jurassic Bt material and Early Cretaceous Ht1 flint. |
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| Locality: | Neuville-sur-Ain / St-André, France, Ain department |
| Synonyms: | Sampling site Bugey 47 after Féblot-Augustins |
| Geographical description: | The material was collected near a slight rise within a large bend of the river "le Suran", just to the NW of St. André, some five kilometres west of Poncin. |
| Geographical co-ordinates: |
east/x 832,5 north/y 2124,8 (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 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 3129 E of the French Institut Géographique National. |
| Geology: |
According to the geological map, the substrate belongs to unit RQ (P1), which consists of residual fluviatile deposits (attributed to the Late Pliocene) with quartzite — and more seldom flint — cobbles. 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: | Apart from the CN2a-flint described here, also several other flint-types of Senonian age can be found here: CN2c, CN3a, CN3b, and CN4c, as well as Early Cretaceous Ht3 silex. |
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| Locality: | Poncin / Chenavel - Chatanay, France, Ain department |
| Synonyms: | Sampling site Bugey 48 after Féblot-Augustins |
| Geographical description: | The sampling-site is located directly adjacent to a narrow road, a bit over a kilometre to the (S)SW of Poncin. |
| Geographical co-ordinates: |
east/x 836,7 to 836,8 north/y 2124 to 2124,2 (Lambert zone II, NTF)
This corresponds roughly with |
| Co-ordinate precision: |
As the site is a few hectares in size, precision is not of the highest importance, but the coordinates lie well within the area. The geographical coordinates point to a spot near the centre of the site. The location can be found on the 1:25 000 topographical map sheet 3230 W of the French Institut Géographique National. |
| Geology: |
The material from this site can be classified as surface-collected flint or in eroded gulleys, Chenavel sector, clays-with-flint of various geological origins (Early and Late Cretaceous); Unit S (Rs). 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: | Besides the Campanian CN2a material, several types of Late Cretaceous material can be found here (CN1a, CN2c, CN4a, CN4b, and CN6), as well as Early Cretaceous Ht3 flint. |
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| Locality: | Neuville-sur-Ain / St-André - les Cochatières, France, Ain department |
| Synonyms: | Sampling site Bugey 60 after Féblot-Augustins |
| Geographical description: | Les Cochatières is located very near the Suran, north of the river at the apex of the very prominent meander near St. André, which lies two kilometres to the west of Neuville-sur-Ain. |
| Geographical co-ordinates: |
east/x 832.2 north/y 2125.7 (Lambert zone II, NTF)
This corresponds roughly with |
| Co-ordinate precision: |
The French coordinates were taken by using the Lambert grid on a detailed topographical map of the area, and are accurate well within 100 metres. The latitude/longitude coordinates are a direct transformation of these data on WGS84 and rounded to the nearest arc-second and are accurate to the same level. The location can be found on the 1:25 000 topographical map sheet 3129 E of the French Institut Géographique National. |
| Geology: |
According to the geological map, the substrate consists of Würmian glacial deposits, unit "a". 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: | All flint from this site belongs to the CN2a type. |
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| Locality: | Neuville-sur-Ain / St-André - Bassement, France, Ain department |
| Synonyms: | Sampling site Bugey 61 after Féblot-Augustins |
| Geographical description: | The sampling site lies in a small wooded valley half a kilometre to the south of the hamlet of Confranchette d'en Bas, which can be reached by following a narrow road for about a kilometre towards the southwest from St-Martin-du-Mont. |
| Geographical co-ordinates: |
east/x 832.3 north/y 2125.7 (Lambert zone II, NTF)
This corresponds roughly with |
| Co-ordinate precision: |
The location was mapped on a large-scale topographical map, from which the French coordinates were taken. The latitude/longitude coordinates are a direct transformation of these data on WGS84 and rounded to the nearest arc-second. The location can be found on the 1:25 000 topographical map sheet 3129 E of the French Institut Géographique National. |
| Geology: |
The flint lies reworked in glacial deposits of Würmian age, unit "a" on the local geological map. 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: | Besides the CN2a-type, also the CN2c variety as well as CN3b flint can be found here. All flints originate in Late Cretaceous limestones, but were transported during the last Ice Age to their current position. |
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| Locality: | Poncin / Sous les côtes (chemin), France, Ain department |
| Synonyms: | Sampling site Bugey 63 after Féblot-Augustins |
| Geographical description: | The sample was collected north of the road that connects Poncin with Leymiat, some 500 metres northwest of the latter village. |
| Geographical co-ordinates: |
east/x 838.8 north/y 2125.1 (Lambert zone II, NTF)
This corresponds roughly with |
| Co-ordinate precision: |
The coordinates given were taken from a detailed topographic 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 3229 W of the French Institut Géographique National. |
| Geology: |
Although the flint itself dates to the Late Cretaceous, it now lies in a secondary position, embedded in fluvio-glacial deposits from the Würm I and II stadials (unit "agl a-b" on the geological map of the region).. 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: | Besides CN2a flint, the CN2b variety can be found here too. |
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| Locality: | Jujurieux / Chenavel - La Route, France, Ain department |
| Synonyms: | Sampling site Bugey 64 after Féblot-Augustins |
| Geographical description: | The sampling site is located near the few houses called "La Route" on the D 36 road, two and a half kilometres north of St-Jean-le-Vieux, not far from where it joins the main N 84. |
| Geographical co-ordinates: |
east/x 836.1 north/y 2121.7 (Lambert zone II, NTF)
This transforms to |
| Co-ordinate precision: |
The Lambert-coordinates given were read from a detailed topographical map, and are within 50 metres of the precise location. The latitude/longitude coordinates are a direct transformation of these data on WGS84 and have the same accuracy. They are given to the apparent high accuracy to prevent the introduction of a rounding-error. The location can be found on the 1:25 000 topographical map sheet 3130 E of the French Institut Géographique National. |
| Geology: |
According to the geological map, the substrate belongs to unit CJy-Z: Colluvial formations, directly reworked from the clayey Miocene substratum. 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: | All flint in this sample belongs to the CN2a-type. |
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| Locality: | Jujurieux / Le Riez (stream), France, Ain department |
| Synonyms: | Sampling site Bugey 65 after Féblot-Augustins |
| Geographical description: | The sample was collected near the southern bank of the small stream "le Riez", a very minor tribituary of the Ain, just to the east of the D 36 road. The site lies a bit over three kilometers east of Pont-d'Ain, and a kilometer south of sampling point 64 described above. |
| Geographical co-ordinates: |
east/x 836 north/y 2120.5 (Lambert zone II, NTF)
This transforms to |
| Co-ordinate precision: |
The Lambert-reference given was read off a detailed topographical map, and accurate to approx. 50 metres. The latitude/longitude coordinates are a direct transformation of these data on WGS84 and have the same accuracy. They are given to the apparent high accuracy to prevent the introduction of a rounding-error. The location can be found on the 1:25 000 topographical map sheet 3130 E of the French Institut Géographique National. |
| Geology: |
According to the geological map, the substrate belongs, like sampling site 64, to unit CJy-Z: Colluvial formations, directly reworked from the clayey Miocene substratum. 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: | All flint in this sample is of the CN2a-type. |
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| Locality: | Jujurieux / Chenavel - Les Brovières 2, France, Ain department |
| Synonyms: | Sampling site Bugey 67 after Féblot-Augustins |
| Geographical description: | The sampling site forms, together with neighbouring Les Brovières 3 & 4, a small cluster of occurrences which lies approx. 150 metres above the bottom of the valley in a bend of the river Ain, about a kilometre and a half southwest of Poncin, and a kilometre to the north of Chenavel. |
| Geographical co-ordinates: |
east/x 836.3 north/y 2124 (Lambert zone II, NTF)
This corresponds with |
| Co-ordinate precision: |
The sites borders on sampling site Les Brovières 3, and might be hard to separate from this site with the precision of the coordinates given, which were take from a large-scale map. The geographical coordinates are a one-to-one transformation of the Lambert-reference The location can be found on the 1:25 000 topographical map sheet 3130 E of the French Institut Géographique National. |
| Geology: |
The sample consists of surface collected flint from an patch of clays-with-flints, which represent the residue of weatherd material of various geological origins (Early and Late Cretaceous). 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: | All flint in this locality is of the CN2a-type, but the nearby sources of Les Brovières 3 and 4 yield flints of respectively the CN1a and CN4a/CN7 types. |
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| Locality: | Poncin / Breignes - Pierre-Feu 1, France, Ain department |
| Synonyms: | Sampling site Bugey 70 after Féblot-Augustins |
| Geographical description: | The sample was collected along a path between the hamlets of Cheneval and Breignes, a hunderd metres to the west of sampling site 34, Poncin / Breignes - Pierre-Feu 2, and 700 metres east of the "le Chanay" farm. |
| Geographical co-ordinates: |
east/x 838.1 north/y 2122.9 (Lambert zone II, NTF)
This corresponds roughly with |
| Co-ordinate precision: |
The coordinates are to the nearest 50 metres on a detailed topographical map. The Lat/Long are a direct transformation of these on WGS84, within the same limits of accuracy. 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 m2bC-Rs : Late continental Miocene (Tortonian) and possibly clays-with-flint of Late Cretaceous origin. 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: | The Late Cretaceous CN1a and CN4c flints occur here too. |
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| Last modified on: November 25, 2005 |
Contents primarily by: Jehanne Féblot-Augustins |
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