Early Kimmeridgian Carbonate Platform, French Jura Mountains
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Swiss J Geosci (2015) 108:273–288 DOI 10.1007/s00015-015-0189-9 Evolution of a Late Oxfordian: early Kimmeridgian carbonate platform, French Jura Mountains 1 2 3 Nicolas Olivier • Elsa Cariou • Pierre Hantzpergue Received: 27 August 2014 / Accepted: 27 March 2015 / Published online: 23 April 2015 Ó Swiss Geological Society 2015 Abstract A detailed facies analysis and interpretation of during the upper Bimammatum Zone caused an increase in the evolution of depositional environments along a north– siliciclastic and nutrient input, leading to a reduction in south transect of the Late Oxfordian—Early Kimmeridgian carbonate production and strong retrogradation of the French Jura carbonate platform highlights hierarchically platform. During the Platynota and lower Hypselocyclum stacked depositional sequences. The identified small- and zones, the shallow inner shelf carbonate production once medium-scale depositional sequences are matched with the more exceeded the accommodation, leading to a general precise cyclostratigraphic framework initially established aggradation of the platform. From the upper Hypselocy- for the Swiss Jura platform. The superimposition of a long- clum Zone, with a more humid climate, the carbonate term (2nd order) sea-level rise with long (400 kyr) eccen- production did not outweigh the accommodation creation tricity cycles explains most of the French Jura platform and the platform evolved to a flat-topped shelf. Thus, sea- architecture. During the Bimammatum and Planula zones, level changes and climatic conditions (temperature and the climate became progressively warmer and more arid, humidity) are the key factors controlling the nature of the allowing enhanced carbonate production. This resulted in a sedimentation and the depositional profile of the French strong progradation of the French Jura platform that pro- Jura platform during the Late Oxfordian—Early gressively evolved from a ramp to an oolitic rimmed shelf. Kimmeridgian. A brief interval characterized by a more humid climate Keywords Carbonate platform Á Depositional sequence Á Depositional environment Á Climate Á French Jura Editorial handling: W. Winkler. Moutains Á Late Jurassic & Nicolas Olivier [email protected] 1 Introduction Elsa Cariou [email protected] The Late Jurassic was a prolific Epoch for carbonate pro- Pierre Hantzpergue duction and widespread carbonate platform construction [email protected] (Kiessling et al. 2003; Leinfelder et al. 2002). Between the 1 Laboratoire Magmas et Volcans, Universite´ Blaise Pascal, Paris Basin to the northwest and the Ligurian segment of CNRS, IRD, OPGC, 5 rue Kessler, 63038 Clermont-Ferrand, the Mesozoic Tethys to the southeast, extensive shallow France carbonate areas constituted the Jura, Lorraine and Swabian 2 Laboratoire de Plane´tologie et Ge´odynamique de Nantes, platforms (Reinhold 1998; Colombie´ and Strasser 2005; Universite´ de Nantes, CNRS UMR 6112, 2, rue de la Carpentier et al. 2010). The growth and demise of these Houssinie`re, BP 92208, 44322 Nantes Cedex 3, France carbonate platforms occurred in various climatic, eustatic 3 Laboratoire de Ge´ologie de Lyon: Terre, Plane`tes, and tectonic contexts (Pittet and Strasser 1998; Pittet et al. Environnement, Universite´ de Lyon, CNRS UMR 5276, Universite´ Claude Bernard LYON 1, Campus de la DOUA, 2000; Jank et al. 2006a; Carpentier et al. 2006, 2007). In- Baˆtiment Ge´ode, 69622 Villeurbanne Cedex, France deed, these ‘carbonate factories’ were controlled by 274 N. Olivier et al. numerous environmental parameters such as water depth, needs to be improved, especially as correlation with the light, nutrient supply, temperature, salinity, hydrodynamic Swiss Jura is still fragmentary. Moreover, the depositional processes, and oxygenation (Lees 1975; Wright and architecture and the nature of the controlling factors (i.e. Burchette 1996; Halfar et al. 2006). Late Jurassic carbo tectonic or eustatic) for the French Jura platform are still nates recorded orbital (Milankovitch) cycles that were re- debated (Cochet et al. 1994). The work presented here sponsible for low-amplitude sea-level changes (Strasser gives a detailed sedimentological analysis of 10 sections 2007; Strasser et al. 1999, 2012). Other factors, apart from along a north–south transect of the French Jura platform sea-level variations, that can affect carbonate production during the Late Oxfordian—Early Kimmeridgian interval. are siliciclastic and nutrient input (Mutti and Hallock 2003; The aims of this paper are (1) to propose a new scheme of Carpentier et al. 2010). The Late Jurassic generally is the French Jura platform architecture; (2) to illustrate a thought to have had an equable global climate and warm common sequential stratigraphic framework between the temperatures (Frakes et al. 1992; Hallam et al. 1993). French and Swiss Jura Mountains; and (3) to decipher the Nevertheless, several recent studies indicate Late Jurassic main stages and mechanisms that governed the evolution of climate variations in shallow platform carbonates with the French Jura platform. short-term sea surface temperature changes in the north- western Tethys (Dromart et al. 2003a, b; Carpentier et al. 2006; Brigaud et al. 2008; Donnadieu et al. 2011; Dera 2 Geographical and palaeogeographical settings et al. 2011). The Late Jurassic Swiss Jura platform has been inten- The study area is located in the Jura chain, which is an arcuate sively studied, and a precise sequential and cyclostrati- fold belt located in front of the western Alpine arc. The 10 graphic framework has been established (Gygi and Persoz studied sections are aligned along a general north–south 1986; Gygi 1986; Strasser 1994; Pittet 1996; Strasser et al. 151 km long transect between Besanc¸on and Oyonnax in 1999, 2000; Colombie´ 2002; Hug 2003; Jank et al. 2006b). eastern France (Fig. 1a). Up to the Late Oxfordian—Early However, these works did not reconstruct a detailed de- Kimmeridgian, the French Jura platform can be subdivided positional architecture of the Late Jurassic Swiss Jura into northern (from Besanc¸on to Champagnole), central platform, which is commonly represented by general (from Champagnole to Saint-Claude) and southern (from lithostratigraphic profiles (Gygi et al. 1998; Gygi 2000). In Saint-Claude to Belley) palaeogeographical sectors (Enay comparison, there are several lithostratigraphic studies for et al. 1988; Cochet 1995; Cariou 2013). Two sections the Late Jurassic French Jura platform available (Enay (Consolation and La Main) are located in the Northern Jura, 1966; Gaillard 1983; Bernier 1984; Enay et al. 1988; Enay five in the Central Jura (Mont-Rivel, La Chaˆtelaine, Loulle, 2000), but only one sequential study (Cochet et al. 1994). Balerne, and Morillon), and three in the Southern Jura Thus, the sequential framework of the French Jura platform (Chancia, Molinges, and Champfromier). During the Late Fig. 1 a Geographical and a Besançon b Rhenish b paleogeographical context at Consolation Massif the Bimammatum/Planula A36 Paris boundary (Late Oxfordian), N57 D461 Paris Basin compiled after Cecca et al. La Main (2005), Hug (2003), Jank et al. Neuchâtel (2006a), and Cariou et al. FRANCE Pontarlier (2014) Basel Mont Rivel Champagnole SWITZERLAND La Châtelaine platform Balerne Loulle A39 Northern Jura Morillon Jura Central Jura N5 Lausanne Central Southern Jura Geneva A1 Land St-Claude (emerged?) Lyon Delphino-helvetic Studied Basin Chancia D436 transect 25° 50 km Molinges Oyonnax Lands Champfromier Upper offshore marls A404 A40 Geneva Tidal flats and limestones Lower offshore marls Nantua Low-energy and limestones shallow carbonates High-energy Basin deposits 25 km shallow carbonates Evolution of a Late Oxfordian: early Kimmeridgian carbonate platform… 275 Jurassic, the platform was part of a large shallow epiconti- framework from the base of the Planula Zone to the top of nental sea, at the northern margin of the oceanic Ligurian the Divisum Zone (Hantzpergue 1975; Cochet 1995). The Tethys, between the Paris Basin to the northwest and the stratigraphic position of the Molinges section is given in Delphino-helvetic Basin to the south (Thierry et al. 2000; Olivier et al. (2011). For the Central Jura, the stratigraphic Fig. 1b). The Jura platform was at a palaeolatitude of around position of the Loulle section refers to Cariou et al. (2014). 26–27°N, with a climate that was subtropical, semi-arid to The litho- and biostratigraphic frameworks presented in arid (Frakes et al. 1992; Dercourt et al. 1993). The platform Table 1, and used for the correlation of studied sections, was at the transition between the Tethyan and boreal realms largely follow the work of Cariou (2013). Only the main (Cecca et al. 2005). The sediments deposited on the Jura lithostratigraphic modifications, with the more recent at- platform mainly correspond to shallow-water carbonates and tempts of Cochet et al. (1994) and Enay (2000), are spe- marls (Gaillard 1983; Bernier 1984; Cochet 1995; Pittet cified below. Major changes concern the Central Jura 1996; Colombie´ 2002; Hug 2003). sector, where the Couches du Morillon Formation is at- tributed to the Bimammatum Zone rather than the Planula Zone. This formation groups the Oolithe du Mont Rivel, 3 Lithostratigraphy and biostratigraphy the Calcaires blancs du Mont Rivel, the Calcaires marneux re´cifaux de Loulle, and the Calcaires de Loulle members There have been several attempts to construct a Late (Cariou 2013). As a consequence, the Central Jura lateral Jurassic lithostratigraphic framework