6 research outputs found
Depositional environments, facies and diagenesis of the Upper Jurassic–Lower Cretaceous carbonate deposits of the Buila-Vânturariþa Massif, Southern Carpathians (Romania)
The Buila-Vânturariţa Massif consists of massive Upper Jurassic reef limestones (Kimmeridgian–Tithonian) and Lower Cretaceous (Berriasian–Valanginian, and Barremian–?Lower Aptian) deposits. Besides corals and stromatoporoids, a wide range of micro-encrusters and microbialites has contributed to their development. In this study, the authors describe briefly and interpret the main facies associations and present the microfossil assemblages that are important for age determination. The distribution of facies associations, corroborated with the micropalaeontological content and early diagenetic features, indicate different depositional environments. The carbonate successions show the evolution of the Late Jurassic–Early Cretaceous depositional environments from slope and reef-front to internal-platform sedimentary settings, including peritidal environments in the lowermost Cretaceous. Early diagenesis, represented by synsedimentary cementation in the form of micritization (including cement crusts in the reef microframework), followed by dissolution, cementation and dolomitization in a meteoric regime, and void-filling late cementation during the burial stage
Palaeoenvironmental changes in the Transylvanian Basin during the Early Miocene revealed by the foraminifera assemblages
The evolution of the Transylvanian Basin during the Early Miocene has been restored from the succession of palaeoenvironments inferred from the sedimentological trend and succession of specific foraminifera assemblages from Lower Miocene Tihău section in northwestern Transylvanian Basin. Planktonic foraminifera suggest a Burdigalian age and recorded sea-level changes, climatic and productivity events. Benthic foraminifera offered valuable data on the palaeoenvironmental evolution, with a large-scale progradational (coarsening up) sedimentary succession influenced by regional tectonics. The succession of depositional events include: i) transgressive coarse grained deposits with typical mediterranean assemblages of bivalves in beach environments; ii) the glauconitic facies which can be associated to the maximum flooding surface of the transgression; iii) the sedimentation continued on a narrow shelf influenced by deltas during the highstand; iv) influence of regional tectonics and subsequent filling with turbidites associated to fan deltas
Triploporella remesi (Steinmann, 1903), dasycladalean green alga from the Tithonian-Lower Berriasian of tramberk (Czech Republic) revisited
The dasycladalean green alga Triploporella remesi (Steinmann) is redescribed based on material collected from the Kotouč quarry near Štramberk (Moravia, Czech Republic), probably corresponding to the type locality. The alga is Tithonian–early Berriasian in age according to the age assigned to the Štramberk Limestone. The new material, in addition to the detailed description of Steinmann, indicates that the short club-shaped calcareous skeleton probably represents the fertile upper part of a far longer club-shaped thallus. The well-developed phloiophorous primary laterals are similar to those of other species of Triploporella in having a proximal cylindrical sterile part followed by a stronger distal cylindrical fertile part. Secondary phloiophorous laterals probably combined to create a cortex at their distal ends. The simple undivided spores inferred by previous authors are shown to be recrystallized cyst containers.Web of Science52339439
Microencrusters from the Upper Jurassic–Lower Cretaceous İnaltı Formation (Central Pontides, Turkey): remarks on the development of reefal/peri-reefal facies
A detailed taxonomical study was carried out for the identification of encrusting micro- organisms. Among these microencrusters, Perturbatacrusta leini, Iberopora bodeuri, Calcistella jachenhausenensis, and Pseudorothpletzella schmidi have been taxonomically revealed for the first time in Turkey. Within the biostratigraphic frame of the I. nalti Formation consisting of Mesoendothyra izjumiana zone ( Kimmeridgian), Calcistella jachenhausenensis zone ( Lower Tithonian- Upper Tithonian) and Protopeneroplis ultragranulata zone ( Upper Tithonian- Berriasian), carbonate sedimentation occurred in five depositional environments comprising slope, fore- reef, reef, back- reef and lagoonal environments. The majority of the reefal deposits of the I. nalti carbonates can be classified as coral- microbial- microencruster boundstones, which frequently occur in association with back- reef and fore- reef deposits within the Kimmeridgian- Berriasian interval. A shallowing and a subsequent deepening of water depth in the Berriasian have been revealed by the examination of stacking patterns and vertical evolution of the microfacies. Based on the observed microfacies and general features of micro- encrusting organisms, it is concluded that I. nalti carbonates share many similarities with the reefal carbonate deposits of Intra- Tethyan domain in terms of microfacies types and microencruster content