(by Jehanne Féblot-Augustins 2005)
|Academic context:||Geological surveys oriented to the identification of lithic raw material sources were conducted between 1995 and 1999 in the Bugey region, in connection with provenance studies (e.g. Féblot-Augustins 2005, 2006) focusing on the Early and Middle I Neolithic of the Gardon cave, excavated by J.-L. Voruz (Voruz et al. 2004). The data concerning the affordances of the Bugey in siliceous raw materials has appeared in reports (Féblot-Augustins 2001) and some of it has been published (Féblot-Augustins 2002, Fillion et al. 2000, Riche & Féblot-Augustins 2002). However, the comprehensive results of the surveys, as well as those of the provenance studies, are awaiting publication in the final Monograph of the Gardon cave (Féblot-Augustins n.d.-a, n.d.-b).
Further information on the sourcing of lithic materials in Gardon Cave and its interpretation is given in an article in the 1st volume of the e-journal Arkeotek by Jehanne Féblot-Augustins: "Raw materials and Early Mediterranean Neolithic expansion process in the upper Rhône basin: the case of the Gardon cave (Ambérieu-en-Bugey, Ain, France)" (see online resources)
Researches undertaken in the Bugey complement other researches of the same type carried out in the Vercors (Riche 1998), in the Chartreuse (Bressy 2003), and in other parts of the Jura (Affolter 2002). By hosting the photographs and the petrographic descriptions of the samples collected in the Bugey, FlintSource.net provides research workers with the opportunity to know more about the stone raw materials available in this part of Europe.
|Geological context:||Bounded on the west by the Revermont and the alluvial plain of the Ain River valley, on the south and east by the Rhône River, on the north by the transverse cluse de Nantua, the Bugey covers the greater part of the southern Jura mountain range (click here for a topographical map of the region, PDF, 77 KB, opens in new window).
The geological history of the Bugey has some bearing on the range of available sedimentary siliceous rocks as well as on the contexts, i.e. primary outcrops vs. secondary alluvial and colluvial deposits, in which they can be found. During the Mesozoic, the region experienced successive marine transgressions, the last of which occurred during the late Cretaceous period.
As a result of tectonic and erosion processes, late Cretaceous Senonian limestone formations are almost entirely lacking, occurring only as thin faulted strips in the very north of the Bugey (click here for a simplified geological map of the Bugey, PDF, 862 KB, opens in new window), while early Cretaceous (Neocomian) and late Jurassic (Malm) formations are preserved in the internal zone of the High Range but not in the western external zone of narrow folds, where only middle Jurassic (Dogger) formations can be observed.
All these formations are known to yield flints in primary contexts, but flints derived from a variety of formations, including the eroded late Cretaceous, and subsequently amalgamated into aggregate deposits can also be found as reworked material in secondary contexts.
|Raw material sources:||The geological surveys (click here for an overview of the topographical maps of the region, PDF, 23 KB, opens in new window) oriented to the identification of lithic raw material sources have resulted in the identification of over 70 such sources (click here for a complete list), in both primary and secondary contexts (click here for a map of all sources, PDF, 274 KB, opens in new window).
The collected samples were characterized using a combination of petrographic techniques such as macroscopic characterization and microfacies analysis (Riche & Féblot-Augustins 2002), an approach that developed in the 1980's (e.g. Séronie-Vivien and Séronie-Vivien 1987) and has increasingly been used since (e.g. Riche 1998, Affolter 2002, Bressy 2003).
In the case of samples from secondary contexts, the help of a micro-palaeontologist was sought in order to check the geological age of the flints: thanks are due to A. Arnaud Vanneau (Laboratoire de Géodynamique des Chaînes Alpines, Grenoble) and to M. Caron (Fribourg University) for their determination of the planktonic foraminifera occurring in Campanian flints.
The range of raw materials that can be found today in the Bugey is quite wide: Bajocian (click here for a map of Bajocian sources, PDF, 190 KB, opens in new window) and Bathonian (click here for a map of Bathonian sources, PDF, 195 KB, opens in new window) flints from the Dogger, Kimmeridgian flints (click here for a map of Kimmeridgian sources, PDF, 427 KB, opens in new window) from the Malm, Valanginian, Hauterivian and Urgonian flints (click here for a map of Early Cretaceous sources, PDF, 300 KB, opens in new window) from the early Cretaceous, Senonian flints (click here for a map of Senonian sources, PDF, 54 KB, opens in new window) mostly of Campanian age from the late Cretaceous, and some rare Cenozoic flints (click here for a map of Cenozoic sources, PDF, 40 KB, opens in new window).
Although samples of Campanian flints were collected in the northern primary outcrops of Leyssard and Solomiat, the bulk of the Senonian samples was found in very localized secondary deposits, where they occur in combination with raw materials derived from other formations. Campanian nodules and pebbles are particularly abundant and varied in the clays-with-flint, Pleistocene, fluvio-glacial and Wurmian deposits of the north-west Poncin sector (Féblot-Augustins 1996).
It should be emphasized that all Senonian flints from these three geographical sectors can be distinguished by either macroscopic or microscopic criteria (Riche & Féblot-Augustins 2002), thus ensuring the accurate sourcing of corresponding flint artefacts.
|The different flint types:||Middle Jurassic|
|Bt2a||middle Bathonian of the so-called "limestones with flint" formations|
|Bt2b||middle Bathonian of the so-called "limestones with flint" formations|
|Bt2||undifferentiated middle Bathonian of the so-called "limestones with flint" formations|
|Bt3||middle Bathonian of the so-called "limestones with flint" formations, or transition with the so-called middle Bathonian "choin" formations|
|Bt4||middle Bathonian of the so-called "choin" formations|
|Bt5||middle Bathonian of the so-called "choin" formations|
|Bt||undifferentiated Bathonian flint|
|Km1||late Kimmeridgian (lower part of the so-called "Tabalcon limestones"?)|
|Km2||late Kimmeridgian (upper part of the so-called "Tabalcon limestones"?)|
|Val||late Valanginian of the so-called "russet limestones"|
|CN1a||Senonian (Campanian) flint from the north-west of the Bugey|
|CN1b||Senonian (Campanian) flint from the north-west of the Bugey|
|CN2a||Senonian (Campanian) flint from the north-west of the Bugey|
|CN2b||Senonian (Campanian) flint from the north-west of the Bugey|
|CN2c||Senonian (Campanian) flint from the north-west of the Bugey|
|CN3a||Senonian flint from the north-west of the Bugey|
|CN3b||Senonian flint from the north-west of the Bugey|
|CN4a||Senonian (Campanian) flint from the north-west of the Bugey|
|CN4b||Senonian (Campanian) flint from the north-west of the Bugey|
|CN4c||Senonian (Campanian) flint from the north-west of the Bugey|
|CN5||Senonian (Campanian) flint from the north-west of the Bugey|
|CN6||Senonian (Campanian) flint from the north-west of the Bugey|
|CN7||Senonian (Campanian) flint from the north-west of the Bugey|
|CN8a||Senonian (Campanian) flint from the north-west of the Bugey|
|CN8b||Senonian flint from the north-west of the Bugey|
|CN8c||Senonian (Campanian) flint from the north-west of the Bugey|
|CE1a||Senonian (Campanian) flint from the north-east of the Bugey|
|CE1b||Senonian (Campanian) flint from the north-east of the Bugey|
|CE1c||Senonian (Campanian) flint from the north-east of the Bugey|
|CE2||Senonian (Campanian) flint from the north-east of the Bugey|
|CE3||Senonian (Campanian) flint from the north-east of the Bugey|
|CE4a||Senonian (Campanian) flint from the north-east of the Bugey|
|CE4b||Senonian (Campanian) flint from the north-east of the Bugey|
|CE5||Senonian (Campanian) flint from the north-east of the Bugey|
|CC2||Senonian flint from the Belley Basin|
|CC3a||Senonian flint from the Belley Basin|
|CC3b||Senonian flint from the Belley Basin|
|CC4a||Senonian flint from the Belley Basin|
|CC4b||Senonian flint from the Belley Basin|
|Attributes described:||Mode of occurrence:describes how and where the flint occurs (outcrop when in primary context, morphology and size of flints, etc.).
Macroscopic visible properties (terms after Luedtke 1992)
Cortex: nature, aspect, colour, thickness, transition (sharp or gradual).
Colour: specified in terms of the Munsell colour chart.
Pattern: refers to the (uneven) distribution of colour, grain, lustre, translucency. Pattern can be featureless, or mottled, streaked, banded (>1cm), laminated (<1cm), spotted/splotched, speckled/flecked, irregularly splotched or mottled, finely laminated with cross bedding, showing convoluted lamination, etc.
Appearance: subsumes fabric (homogeneous/non homogeneous); lustre (shiny, medium or dull, silky, greasy, pearly, waxy); translucency (highly translucent, translucent, subtranslucent, opaque; feel (rough, smooth), and grain (fine, medium or coarse).
Microscopic visible properties (binocular microscope, magnification 40x)
Structure: refers to the way the elements (grains) are arranged, conditioned by the original sedimentary context of deposition. E.g.: stratified/bedded, finely laminated, finely laminated with cross bedding, in form of graded bedding, convoluted, well or poorly sorted, oriented (i.e. showing a fluidal arrangement of grains), etc.; presence of micro-vugs or pores.
Texture: refers to the nature of and the relationship between the different constituents of a particular rock. Specified in terms of Dunham's classification for carbonate rocks (Dunham 1962), namely, mudstone, wackestone, packstone and grainstone.
Matrix:refers to translucency of the matrix (sedimentary material) found between grains within a rock.
Grains: mean estimate of quantity, colour, morphology (i.e., roundness and sphericity), size.
Grain composition: coated grains (ooliths, ooids, oncoids), grain aggregates, clasts, peloids/pellets; skeletal grains (e.g. from foraminifera, bryozoans, sponges, ostracods, brachiopods, gastropods, lamellibranchia/pelecypods, echinoderms, radiolarians, serpulids, corals, incertae sedis, etc.); algae; organic matter; other elements (quartz, glauconite, pyrite, mica, iron oxides, etc.).
|Contact the author:||Jehanne Féblot-Augustins
UMR 7055 - Préhistoire et Technologie
Maison de l'Archéologie et de l'Ethnologie - René Ginouvès
21, allée de l'Université, 92023 Nanterre Cedex
In the above mail-address, substitute <at> by the @-sign.
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The information on the flints from the Bugey might be cited as:
Féblot-Augustins, J. (2005)
Flints from the Bugey, France
|Last modified on:
February 17, 2007
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