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 Mihajlovići 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 Sine-murian/?earliest Pliensbachian open-marine shallow subtital micro-oncoidal limestones; 2) ?early to Late Pliensbachian open-marine condensed limestones with few micro-oncoids and more open-marine influence; 3) Toarcian open-marine condensed red limestones with hardgrounds; and 4) condensed red nodular Bositra Limestone. These four members are separated by hard-rounds representing stratigraphic 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.
Original language | English |
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Pages (from-to) | 1-25 |
Number of pages | 25 |
Journal | Geološki anali balkanskoga poluostrva : Annales Geologiques de la Peninsule Balkanique |
Volume | 82.2021 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2021 |