Reassessment of amber-bearing deposits of Provence, southeastern France

The presence of “geological” amber (or “succin” in old French monographs) has been reported for several centuries in the Mesozoic deposits of Provence, southeastern France. Diverse amber-bearing sites were inventoried by the authors but their location and stratigraphical context remain unclear for most of them. In the past decades, various data concerning chemistry, palaeontological content and comparison with archaeological discoveries improved our knowledge of the ambers of Provence, but only those of Cretaceous age. The present paper aims at providing a comprehensive description of all the presently known amber-bearing deposits of Provence, including the description of new sites. We highlight the great potential of Provence ambers and allow to consider a wider time range, from the Early Cretaceous to the Miocene.


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The main outcrops are located northeast of the Piolenc town in a neighbourhood called 124 "quartier de Saint Louis". There, ancient abandoned quarries (Tab.1, site 1a) allow the 125 observation of 20 m-thick series of the Piolenc lignite Formation. According to Gomez et al. 126 (2003), nine units (from bottom to top) are observed. The sedimentological and palaeobotanical 127 data document an intertidal to supratidal environments, with coastal ponds, marked by 128 instability depending on the variations in the water level, under a hot humid tropical climate. 129 Amber grains have been found in the lower unit, in foliated sandy clays (unit a). 130 The sedimentary series shows a significant lateral facies changes ( Fig. 3A-C). At the base of 131 the quarry, above yellowish sandstone exhibiting cross-bedded stratification, the presence of 132 tiny beads or larger nodules of amber is easily observed in sandy levels ( Fig. 3A-B, Fig. 4B, C) 133 and in overhanging foliated sandy clays (Fig. 3D). Amber is also found at the base of a 134 sandstone bed which can be clearly identified in the topography (unit d in Gomez et al., 2003) 135 and in the overlying levels ( Fig. 4A), made of laminated sandy sediments (Fig. 3B). The last 136 amber grain occurrence is found in the the root level (unit e in Gomez et al., 2003) (Fig. 3E). It 137 should be noted that amber was also harvested at the top of the hill to the northwest on the so-138 called "Montée de Béziers" (Tab. 1, site 1b). 139 In the richer lignite levels, the amber grains are mixed into a gangue composed of compacted 140 plant debris (Fig. 4D). The amber grains show two types of morphology. The majority of the 141 samples are in the form of millimetric to centimetric, more or less elongated beads or droplets 142 ( Fig. 4E-J). Some larger nodules with various shapes can reach up to 4-5 centimetres (Fig. 4G). 143 The amber grain aspect is variable, from translucent reddish yellow (Fig. 4E, H) to completely 144 opaque (Fig. 4F, I). They often bear a fine reddish to brownish crust (Fig. 4H, J) on the finely 145 cracked surface. 146 Despite its abundance, the Piolenc amber has provided very few arthropod inclusions, 147 including two species of small dolichopodid flies (Nel et al., 2017) and two new species of  (Fig. 1B, site 2 ; Fig. 2) 154 Lignite deposits have long been mined at Bédoin and used as firewood for silkworm rooms, 155 for cooking lime and plaster (Perdonnet et al., 1837). There, the lignite layers occur in a thick 156 set of several tens of meters of marly, sandy and sandstone sediments in a thick set of several 157 tens of meters of marly, sandy and sandstone sediments having partially undergone alteration 158 phenomena (= "faciès rutilant" of Jacob, 1907). The age of these levels is between the Albian 159 and the lower Cenomanian (Jacob, 1907;Sornay, 1945Sornay, -1946. Only a more recent study (Triat,  grading upward into sandstone limestone. According to Triat (1982), a more clayed level 165 represents the passage between Albian sands (sl) and Vraconian deposits (ss) deposits. The 1/50 166 000 geological map of Vaison-la-Romaine (Monier and Cavelier, 1991) assigns the outcrop to 167 n7A (Albian-Vraconian) due to the alteration of red sands of marine origin. Our field 168 investigations confirmed the presence of amber in the level indicated by Triat (1982) and 169 representative material has been collected in situ. The samples were observed and collected 170 about 1 metre above the top of the ochreous sandston, rich in oyster shells ( Fig. 5B-D). Amber samples are representated by large nodules associated with more or less lignitised 172 plant debris (Fig. 5D-F). The periphery of the amber nodules develops a sandstone concretion, 173 encompassing both amber masses, woody debris and plant remains (Fig. 5F).

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The collected nodules and fragments of amber have a dominant reddish hue in the translucent 175 parts (Fig. 6A). However, we often see an earthy beige-brown hue making the grains opaque 176 (Fig. 6A-B). The amber cross sections show successive resin flows including dust residues and 177 small bubbles of high density (Fig. 6C).

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According to Triat (1982), the Albian sands correspond to a shallow marine environment, 179 while the overlying Vraconian sandstone limestones mark a marine deepening.

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It is interesting to note that a humerus of a dinosaur identified as belonging to the genus 181 Aepisaurus has been found in the Albian sandy facies (Gervais, 1848(Gervais, -1852Brignon, 2018). In 182 the lack of data regarding its precise stratum, one may hypothesise that this dinosaur remain 183 originates from the amber-bearing level which yield terrestrial elements such as plant debris.  More precisely, the 1/50, 000 geological map of Carpentras assigns these pyritic black marls a 190 Gargasian age (n6a) based on the macrofauna and microfauna (Blanc et al., 1975).

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Unfortunately we have no other indication on this amber regarding its exact location, its 192 appearance and its abundance. New field researches are thus required to confirm the presence 193 of this amber and its habitus. Bréhéret (1995) reported south of the Eygaliers village (Fig. 1, site B), many woody debris 197 and amber grains in glauconitic sandstones cropping out above Albian sediments. A basal 198 Cenomanian age is tentatively assigned to these amber-bearing deposits. There is no indication 199 of the appearance of this amber. and Albian terranes north of Salignac (Fig. 7). Several deposits, ranging from Aptian to 215 Cenomanian ages, yield amber. They are detailed as follow.

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The only sample of Aptian age was taken north of Salignac near the Les Coignets locality sections made on this sample show a fairly concentric irregular structure reflecting successive 220 resin flows (Fig. 9B). A central part is more translucent, reddish in color. The periphery appears 221 as an opaque yellow-orange crust.

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Albian amber grains can be harvested at the Les Coulets locality in the hills and ravines 223 oriented preferentially East-West and dipping south (Fig. 1B, site 3b, Fig. 7; Tab. 1). The area 224 exhibiting in situ amber samples (Fig. 8A, B) is located between two index levels: 100 metres     The Albian series well-exposed at Salignac outcrops west of the Durance south of the 260 Aubignosc village (Fig. 7) and also contains amber. The 1/50,000 geological map of Sisteron Pseudosuccinite defined by Buddhue (1938). This amber was subsequently analyzed by 281 infrared spectra (Beck and Liu, 1976). According to the 1:50,000 geological map of Sault, the 282 Eygrières amber merely come from the Cenomanian marly-sandstone terranes. 283 We have examined samples from Saint-Etienne-des-Orgues from private collections (F. The presence of amber in northwest Blieux is only known from Bréhéret (1995) who 290 reported black horizons with driftwood and amber interspersed in Albian dark marly sediments. 291 We do not know the characteristics of this amber.    sector is moreover very difficult to define due to the strong deformations which affect the series 321 at the heart of a syncline whose axis is parallel to the coast (Guieu et al., 1996). The Santonian  Campanian but restricted to its lower part (~c33).

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As regarding flora, the Level 3 is remarkable for having yielded some trunks fragments likely 402 belonging to conifers (Gomez, pers. com.) and some amber grains, objects of this study.

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Some of them exhibit a drop shape, but many are fragments only. The samples show all the 405 intermediaries between translucent reddish grains and completely opaque grains, from red to 406 whitish in external appearance. Some grains have a peripheral crust (Fig. 12 I), darker red in 407 section (Fig. 12H). Many opaque grains show a dark red hue in section with inclusions of dark 408 unidentifiable organic debris. One can observe under SEM the imprints of a mineral belonging 409 to the cubic system (Fig. 12K). This could correspond either to pyrite crystals already 410 mentioned in some amber but apparently absent in the samples, or to salt crystals dissolved 411 subsequently. Among the inclusions particularly difficult to identify, there are ovoid structures 412 with a wrinkled surface which could perhaps correspond to spores (Fig. 12J). It is important 413 that during the mounting of thin sections process, the amber tended to creep like a resin which 414 is not fully consolidated (Fig. 12H). The amber-bearing sites of Santonian age are distributed in a direction approximately East-

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West at the foothill of the Sainte-Baume Massif (Fig. 1B, sites 12, 13). 419 The only mentions of the presence of amber in the Var department were given during the   (Nury, 1988).

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A millimeter-sized grain of amber was extracted from the matrix of an undetermined turtle 437 shell (Fig. 13). The grain has a thick opaque beige crust of around 200 µm around a more   The harvested amber grain is quite translucent, orange-red in colour. Its globular shape is 455 approximately 1,6 cm in size (Fig. 14D). Examination does not reveal any inclusion.