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Bt

Material name:	Bt
Synonyms:	N/A
Material (geologic):	undifferentiated Bathonian flint

Foto: Jehanne Féblot-Augustins, 2005.

Sampled sites:

Le Plan
Breignes-Pierre-Feu 2

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Material description

Description: The Bt-type groups together flints collected in secondary context, in the clays-with-flint resulting from the decalcification of Bajocian and Bathonian flint bearing formations. The flints are weathered, whitish (or stained pink), dull and opaque, and of very mediocre quality.
Their overall characteristics (in particular the absence of laminations) allow them to be attributed to the Bathonian rather than to the Bajocian, without any further distinction.

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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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 the undifferentiated type Bt4, this residual source also yields Late Bajocian flints of the Bj3 and Bj4c varieties, as well as other Bathonian flints of the types Bt1 and Bt4.

Foto: Jehanne Féblot-Augustins, 2005

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Breignes-Pierre-Feu 2

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 Lat. 46° 03' 52" N Long. 005° 24' 58" E (WGS84)
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 material are, according to the geological map, Late Miocene (Tortonian) continental sediments, belonging to the stratigraphic unit m2bC.The reworked flints themselfs seem to originate from Bathonian limestones. 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 the general Bathonian Bt-type, flints of the Cretaceous types Ht1, CN1a, CN2a and CN8c can be found here too.

Foto: Jehanne Féblot-Augustins, 2005

Foto: Jehanne Féblot-Augustins, 2005

Last modified on:
November 15, 2005

Contents primarily by:
Jehanne Féblot-Augustins

Comments to:

Description:	The Bt-type groups together flints collected in secondary context, in the clays-with-flint resulting from the decalcification of Bajocian and Bathonian flint bearing formations. The flints are weathered, whitish (or stained pink), dull and opaque, and of very mediocre quality. Their overall characteristics (in particular the absence of laminations) allow them to be attributed to the Bathonian rather than to the Bajocian, without any further distinction.
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.