Stratigraphy and Mineralostratigraphy of the Kimmeridgian in the Central Jura Mountains of Switzerland and Eastern France
Total Page:16
File Type:pdf, Size:1020Kb
Stratigraphy and mineralostratigraphy of the Kimmeridgian in the central Jura mountains of Switzerland and eastern France Autor(en): Mouchet, Philippe O.J. Objekttyp: Article Zeitschrift: Eclogae Geologicae Helvetiae Band (Jahr): 91 (1998) Heft 1 PDF erstellt am: 04.10.2021 Persistenter Link: http://doi.org/10.5169/seals-168408 Nutzungsbedingungen Die ETH-Bibliothek ist Anbieterin der digitalisierten Zeitschriften. Sie besitzt keine Urheberrechte an den Inhalten der Zeitschriften. Die Rechte liegen in der Regel bei den Herausgebern. Die auf der Plattform e-periodica veröffentlichten Dokumente stehen für nicht-kommerzielle Zwecke in Lehre und Forschung sowie für die private Nutzung frei zur Verfügung. Einzelne Dateien oder Ausdrucke aus diesem Angebot können zusammen mit diesen Nutzungsbedingungen und den korrekten Herkunftsbezeichnungen weitergegeben werden. Das Veröffentlichen von Bildern in Print- und Online-Publikationen ist nur mit vorheriger Genehmigung der Rechteinhaber erlaubt. Die systematische Speicherung von Teilen des elektronischen Angebots auf anderen Servern bedarf ebenfalls des schriftlichen Einverständnisses der Rechteinhaber. Haftungsausschluss Alle Angaben erfolgen ohne Gewähr für Vollständigkeit oder Richtigkeit. Es wird keine Haftung übernommen für Schäden durch die Verwendung von Informationen aus diesem Online-Angebot oder durch das Fehlen von Informationen. Dies gilt auch für Inhalte Dritter, die über dieses Angebot zugänglich sind. Ein Dienst der ETH-Bibliothek ETH Zürich, Rämistrasse 101, 8092 Zürich, Schweiz, www.library.ethz.ch http://www.e-periodica.ch 0012-9402/98/010053-16 $1.50 + 0.20/0 Eclogae geol. Helv. 91 (1998) 53-68 Birkhäuser Verlag. Basel. 1998 Stratigraphy and mineralostratigraphy of the Kimmeridgian in the central Jura mountains of Switzerland and eastern France1 Philippe O. J. Mouchet2 Key words: Kimmeridgian. microfacies, mineralostratigraphy. kaolinite. major discontinuities. Jura mountains Mots clefs: Kimmeridgien. microfaciès, mineralostratigraphic kaolinite. discontinuités majeures. Jura ABSTRACT RESUME The microfacies, micropaleontologv. mineralogy and sedimentology of the Les séries kimméridgiennes. très pauvres en éléments biologiques de datation series of the Reuchenette Formation (Kimmeridgian), introduced by Thalmann ont été étudiées sous leurs aspects microfaciologiques. micropaléontologiques. (1966) to replace the Kimmeridgian auctorum. have been studied and minéralogiques et sédimentologiques. L'étude inclut la localité-type de la compared with other series in the Swiss and French Jura Mountains. The studied Formation de Reuchenette. introduite par Thalmann (1966) pour remplacer le area corresponds to a shoal environment separating the Tethys (S) and the Kimmeridgien auctorum. Ces séries, principalement calcaires, ont été ensuite Paris Basin (N). The depositional environments represent three major comparées avec les séries du Jura suisse et français. Le domaine étudié domains: intertidal/supratidal domain, internal platform and external platform correspond à un haut-fond séparant la Téthys (S) du Bassin de Paris (N). Les (margin and slope). Field observations and microfacies analysis revealed two environnements de dépôt représentent trois domaines majeurs: domaine major discontinuities. Clay-mineralogy data show that kaolinite can be used as margino-littoral. plate-forme interne et plate-forme externe (bordure et talus a stratigraphical marker. Both methods, microfacies and clay-mineralogy, externe). L'analyse des microfaciès a permis de mettre en évidence deux allowed to establish correlations in an area where the biochronological markers discontinuités majeures. L'analyse minéralogique a permis d'identifier la kaolinite are extremely rare. The two major discontinuities can be correlated with series comme marqueur minéralostratigraphique. Grâce à l'étude combinée des described by Bernier (1984). Chevallier (1989) and Strohmenger et al. (1991) microfaciès et des minéraux argileux, il a été possible d'établir des corrélations in the Jura of SE France (Jura méridional) and can be tied to the global eustatic fiables pour l'ensemble du domaine étudié. Les deux discontinuités majeures curve established by Haq (1991). se corrèlent avec les séries du Jura méridional décrites par Bernier (1984). Chevallier (1989) et Strohmenger et al. (1991) et peuvent être reliées avec la courbe eustatique globale de Haq (1991 Introduction Heim (1919) subdivided Rollier's Kimmeridgian in Ptero- cerian and Virgulian. Heim's Kimmeridgian corresponds to Thurmann (1832) introduced the name Kimmeridgian as one the Lower Kimmeridgian of England, as described by Arkell of the stratigraphie subdivisions of the Jura Mountains' Upper (1956). finishing with the Aulacostephanus pseudomutabilis Jurassic by naming "Kimeridgian Marls" the "Beds with Ptero- Zone. In England, the Middle Kimmeridgian starts with the ceras". These were placed as 2nd division in the lower part of Gravesia sp. Zone, which, however, following the continental the Portlandian Group (Fig. 1). European tradition, defines the base of the Portlandian. The Marcou (1848) divided Thurmann's Portlandian Group Kimmeridgian sensu gallico corresponds thus to the Lower into two members: the "Kimmeridge marls" (or "Banné Kimmeridgian in England. Recent studies of Amoeboceras Marls") and the "Kimmeridge Limestones", both considered faunas (Atrops et al., 1993) have shown that the lower part of as purely lithostratigraphic units. the Submediterranean latest Oxfordian Planula Zone correlates Rollier (1888, 1893, 1898), for the first time, published a with the lower part of the Subboreal Kimmeridgian complete section of the Malm in the Jura Mountains of the Baylei Zone and that the lower part of the Submediterranean canton Bern. He recognized and delimited three stages: Kimmeridgian Platynota Zone correlates with the upper part Sequanian (top represented by the "St.-Verena Oolith"), of the Subboreal Baylei Zone (Fig. 2). This indicates that the Kimmeridgian (top represented by the "Banc à Nérinées" or the boundary between the Oxfordian and Kimmeridgian is actual- "Exogyra virgula Marls") and Portlandian. 1 Ph.D. Thesis. Université de Neuchâtel. projets Fonds National de la Recherche Scientifique n"21-29909.90 & 20-35878.92 : PO Box 306. Tennant Creek 0861. Northern Territory. Australia Kimmeridgian central Jura Mountains 53 | Thurmann (1832) Marcou (1857-60) Heim (1919) ARKtLL(l956) i Thalmann (1966) — PORTLANDIEN ~ - Twannbach- 1. Division 5 _- formation Calcaires Gravesia spp. porti andiens Z Aulacostephanus. < autissiodorensis 5 Y. VIRGULIEN __ _- A. eudoxus Reuchenette- | ^ A. mutabilis formation Cale, du Banne __ 2. Division Mames Marnes du Banne PFEROCERIEN Rasenisi cvmodoee kimméridiennes s __ Pictiona baylei D Rinsta edia Verenaschichten Z -_ pseudocordata __ Ç 3. Division Calcaires ii y- Z SEQUANIEN < C < Astartes SEQUANIEN a Fig. 1. Subdivisions of the Malm from Thurmann (1832) to Thalmann (1966). ly drawn at a higher level in the Submediterranean zonal meridgian age for strata classically placed in the earliest scheme than in the Subboreal one. The Kimmeridgian of this Portlandian. It appears thus that, in the Jura Mountains, both study is used in the classical sensu gallico. Kimmeridgian and Portlandian were never precisely dated with Biological markers (ammonites, foraminifera) are very rare biostratigraphic markers. The names Oxfordian, Kimmeridgian in these series and. therefore, precise chronostratigraphical and Portlandian have classically been used in an approximate correlations are difficult to establish. One ammonite (Phylloceras chronostratigraphical sense. The conventional boundaries cf. tenuisculptum) of Kimmeridgian age was found at of these "stages" correspond to lithological markers Morillon (Fig. 3, 4). The charophytes (Echinochara pecki, which are supposed to be more or less isochronous and to Porochara sp.) indicate also a Kimmeridgian age for these correspond to the international stage boundaries. series but are of no use for more accurate correlations. The Thalmann (1966) introduced the name of "Reuchenette combined first appearance of Clypeina jurassica and Campbelliella Formation" for the Kimmeridgian strata of the Swiss Jura striata in the studied series can be used as a complementary mountains. This formation is defined by the same lithostratigraphical tool for correlations (Strohmenger et al. 1991). According to boundaries as used by Rollier (1888) nearly a century Gygi (1995) a find of Aspidoceras cf. acanthicum just above ago. the Virgula Beds at Alle (canton Jura) indicates a late Kim- Bernier (1984) and Chevallier (1989) recognized and described several formations of Kimmeridgian age (sensu gallico) in France. Most of these (like "Calcaires et Marnes de Europe Europe Chargey". "Calcaires et Marnes de Matafelon". etc.) are not Subboreal Submediterranean easily recognizable in the field outside road cuts. They have no Autissiodiorensis Beckeri direct equivalent in Switzerland. Only the following formations or layers are clearly and easily Kimmeridgian gallico recognizable by their lithology (Fig. 1): the "St.-Verena Eudoxus Eudoxus Oolith". the "Banné Marls", the "Banc à Nérinées" and the sensu "Exogyra virgula Marls". The "Reuchenette Formation" does Upper not possess a characteristic lithological content (Gygi 1995) bui Mutabilis Acanthicum its limits are clearly identifiable, in a part of the studied region. e cd Divisum Persoz & Remane (1973. 1976) analysed the microfacies '5) •o c; in 'C and the mineralogy