Early-Middle Jurassic stepwise deepening in the transitional facies belt between the Adriatic Carbonate Platform Basement and Neo-Tethys open shelf in northeastern Montenegro evidenced by new ammonoid data from the early Late Pliensbachian Lavinianum Zone

  • Martin Djakovic Geological Survey of Montenegro
  • Hans-Jürgen Gawlick Montanuniverität Leoben, Department Angewandte Geowissenschaften und Geophysics, Leoben, Austria
  • Milan Sudar Serbian Academy of Sciences and Arts, Kneza Mihaila 35, 11000 Belgrade
Keywords: Western Tethys, Dinarides, Pliensbachian, ammonoids, biostratigraphy, NE Montenegro

Abstract

New ammonoid data prove an early Late Pliensbachian deepening event above the ?Late Hettangian-Sinemurian shallow-subtidal gray-reddish micro-oncoidal-foraminifera grainstone facies and the ?Early Pliensbachian deeper-marine micro-oncoidal-crinoidal-ammonoid wacke- to packstone facies. Based on the presence of Fuciniceras lavinianum (Fucini), Lytoceras ovimontanum Geyer and Arieticeratinae gen. indet. from a hardground above the deeper-water micro-oncoidal limestones in the Mihajlovici section (northeastern Montenegro) a Late Pliensbachian to Early Toarcian condensation horizon is proven. The Middle Toarcian ammonoid-bearing horizon also yielded species not known from previous studies: Calliphylloceras capitanii (Catullo), Harpoceras subplanatum (Oppel) and Furloceras aff. chelussii (Parisch & Viale), also described in the present paper. These new data prove a stepwise deepening of the depositional area during the Early and the Middle Jurassic reflected in detail in four sedimentary members: 1) ?Late Hettangian to Sinemurian/? earliest Pliensbachian open-marine shallow subtital micro-oncoidal limestone; 2) ?Early to Late Pliensbachian open-marine condensed limestones with few micro-oncoids and more open-marine influence; 3) Toarcian openmarine condensed red limestones with hardgrounds; and 4) condensed red nodular Bositra Limestone. These four members are separated by hardrounds representing Stratigraphie gaps in deposition. The stepwise deepening during the Early-Middle Jurassic follows the general trend of deposition as known in the whole Western Tethys Realm above the Late Triassic Dachstein Carbonate Platform.

 

Published
2021-08-02
How to Cite
Djakovic, M., Gawlick, H.-J. and Sudar, M. (2021) “Early-Middle Jurassic stepwise deepening in the transitional facies belt between the Adriatic Carbonate Platform Basement and Neo-Tethys open shelf in northeastern Montenegro evidenced by new ammonoid data from the early Late Pliensbachian Lavinianum Zone”, Geološki anali Balkanskoga poluostrva, 82(1), pp. 1-25. doi: 10.2298/GABP201230001D.
Section
Original Scientific Paper