[ home ]

Bt1

Material name:	Bt1
Synonyms:	N/A
Material (geologic):	Middle Jurassic (Early Bathonian) flint

Foto: Jehanne Féblot-Augustins, 2005.

Sampled sites:

Le Plan
Tenay-Lower quarry 2
Gardon-Chemin 1 et 3
Col de la Berche

[ top ] [ home ]

Material description

Mode of occurrence: Large globular or ramified nodules, very tectonised, 15 to 20 cm across.

Cortex: Rough, reddish yellow, 0.5 cm, transition sharp.

Colour: Medium blue-grey (N5 to N6).

Pattern: Slightly mottled, numerous macroscopic inclusions.

Appearance: Homogeneous material, although fractured and jointed, dull and opaque, moderately fine-grained.

Structure: Convoluted bioturbation figures and algal laminations (oncoliths).

Texture: Mudstone, with wackestone zones.

Matrix: Opaque.

Grains: 7.5 to 10 %, locally up to 20 %, pale, subrounded with high sphericity, or irregularly shaped, poorly sorted (100 µ to 8 mm).

Grain composition: Algae (Dasycladaceae and Solenoporaceae), sponge spicules, pelecypods, entrochi, brachiopods, rare bryozoans, pellets; detrital quartz, 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.

[ top ] [ home ]

Le Plan

Locality:	Ambérieu-en-Bugey / Vareille - Le Plan, France, Ain department
Synonyms:	Sampling site Bugey 14 after Féblot-Augustins
Geographical description:	The source lies on a hilltop approx. 1 kilometre east of the hamlet St. Germain, a couple of kilometres southeast of Ambérieu-en-Bugey.
Geographical co-ordinates:	east/x 836.4 north/y 2110 (Lambert zone II, NTF) This corresponds roughly with Lat. 45° 56' 56" N Long. 005° 23' 11" E (WGS84)
Co-ordinate precision:	The coordinates given were taken from a large-scale map, and are within approx. 50 - 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, 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 3130 E of the French Institut Géographique National.
Geology:	The underground at the sampling-site is a clay-with-flints which resulted from the decalcification of several flint-bearing formations dating to the Bajocian and Bathonian (units J1a-b and J1c from the Bajocian and J2 from the Bathonian). Map of all sampled localities of Bathonian flint in the Bugey (PDF, 195 KB, opens in new window).
Type of source:	Secondary.
Other types of flint:	Besides type Bt1, this residual source also yields Late Bajocian flints of the Bj3 and Bj4c varieties, as well as other Bathonian flints of the types Bt4 and Bt.

Foto: Jehanne Féblot-Augustins, 2005

[ top ] [ home ]

Tenay-Lower quarry 2

Locality:	Tenay / Lower quarry 2, France, Ain department
Synonyms:	Sampling site Bugey 18 after Féblot-Augustins
Geographical description:	The sample comes from a quarry at the foot of the mountain directly to the northwest of Tenay.
Geographical co-ordinates:	east/x 845.9 north/y 2107.3 (Lambert zone II, NTF) This corresponds roughly with Lat. 45° 55' 17" N Long. 005° 30' 26" 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 therefore also within the same error-margin. 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 the lower part of unit J2 (Bathonian). 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:	From the same quarry also comes flint of the Bt4 type, which comes approx. 30 yards to the west of the Bt1 material, and a little higher in the stratigraphy. Within the flint-bearing layers, there is probably a small geologic fault.

	Foto: Jehanne Féblot-Augustins, 2005	Foto: Jehanne Féblot-Augustins, 2005
	Foto: Jehanne Féblot-Augustins, 2005

[ top ] [ home ]

Gardon-Chemin 1 et 3

Locality:	Ambérieu-en-Bugey / Les Balmeaux - Gardon, Chemin 1 et 3 , France, Ain department
Synonyms:	Sampling site Bugey 30 after Féblot-Augustins
Geographical description:	The sampling location is located at the foot of a steep cliff near Gardon cave, approximately 2 kilometres east of Ambérieu-en-Bugey.
Geographical co-ordinates:	east/x 836.4 north/y 2110.8 (Lambert zone II, NTF) This corresponds roughly with Lat. 45° 57' 22" N Long. 005° 23' 12" E (WGS84)
Co-ordinate precision:	The coordinates were read off a large-scale map, and are within approx. 50 metres of the actual spot. The transformation to lat/long was performed on the exact figures given for the Lambert-coordinates, so their precision is in the same order of error. The location can be found on the 1:25 000 topographical map sheet 3130 E of the French Institut Géographique National.
Geology:	The sample was collected from a secondary position on the surface, and is presumably weathered from limestones of Early Bathonian age. Map of all sampled localities of Bathonian flint in the Bugey (PDF, 195 KB, opens in new window).
Type of source:	Secondary.
Other types of flint:	Apart from this flint, also material belonging to the type Bt4 can be found here.

Foto: Jehanne Féblot-Augustins, 2005

[ top ] [ home ]

Col de la Berche

Locality:	Hauteville-Lompnes / Col de la Berche sud , France, Ain department
Synonyms:	Sampling site Bugey 40 after Féblot-Augustins
Geographical description:	The sample was collected in wooded terrain just south of the col, and with it road D8, which runs toward the northwest from Hauteville-Lompnes.
Geographical co-ordinates:	east/x 849 north/y 2115.4 (Lambert zone II, NTF) This corresponds roughly with Lat. 45° 59' 35" N Long. 005° 33' 06" E (WGS84)
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, 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 3230 W of the French Institut Géographique National.
Geology:	According to the geological map, the substrate is a residual clay-with-flints resulting from the decalcification of (Early) Bathonian limestones (unit J2). Map of all sampled localities of Bathonian flint in the Bugey (PDF, 195 KB, opens in new window).
Type of source:	Secondary.
Other types of flint:	Although this is a secondary source, all material found here belongs to the same type, Bt1.

Foto: Jehanne Féblot-Augustins, 2005

Last modified on:
November 15, 2005

Contents primarily by:
Jehanne Féblot-Augustins

Comments to:

Mode of occurrence:	Large globular or ramified nodules, very tectonised, 15 to 20 cm across.
Cortex:	Rough, reddish yellow, 0.5 cm, transition sharp.
Colour:	Medium blue-grey (N5 to N6).
Pattern:	Slightly mottled, numerous macroscopic inclusions.
Appearance:	Homogeneous material, although fractured and jointed, dull and opaque, moderately fine-grained.
Structure:	Convoluted bioturbation figures and algal laminations (oncoliths).
Texture:	Mudstone, with wackestone zones.
Matrix:	Opaque.
Grains:	7.5 to 10 %, locally up to 20 %, pale, subrounded with high sphericity, or irregularly shaped, poorly sorted (100 µ to 8 mm).
Grain composition:	Algae (Dasycladaceae and Solenoporaceae), sponge spicules, pelecypods, entrochi, brachiopods, rare bryozoans, pellets; detrital quartz, 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.