P. Tchoumatchenco. Stratigraphic and palaeogeographic reconstruction of the Lower and Middle Jurassic based on olistoliths embedded in the Kotel Formation (Eastern Stara Planina, Bulgaria). The Kotel Olistostrome Formation in the Eastern Stara Planina contains olistoliths of various Jurassic rocks grouped in four facial types corresponding to different palaeogeographic areas of the ancient basin where the rocks were originally formed. These are the facial types of Bilka, Djula, Karaveljovo and Čerkovište. The Bilka facial type was formed in a lagoon. It consists of pink aphani te limestones overlying transgressively Upper Triassic reef and subreef limestones. They are of Pliensbachian age. The upper part of their overall section is crosscut by Toarcian-Middle Jurassic neptunian dykes containing numerous brachiopods. The Djula facial type was formed in the sublittoral zone dominated by a high-energy environment involving tidal and bottom curents. It consists mostly of grey-black or red detrital limestones overlying transgressively Middle and Upper Triassic carbonates. The transgression involved quartz sandstones. The top of the cumulative section consists of grey-black aleuritic argillites and aleurolites. The age of this facial type range from the Sinemurian to the Bajocian. The Karaveljovo facial type was formed as a bar on the shelf in a high-energy environment dominated by a strong bottom current. It consists of Domerian-Toarcian biodetritical marls and limestones. The underlying rocks are not known. The Čerkovište facial type was formed in the environment of the open-sea shelf and probably in the upper part of the epibathial zone. It consists of red aleuritic marls and limestones whose age ranges from the Sinemurian to the Toarcian. The underlying rocks are not known.
A. A. Alizade, H. Alijula, R. H. Momedzade. Stratiwaphic scheme oi the Upper Cretaceous in the Azerbaidzanian part oi Lesser Caucasus. Compilation of unified strati graphic schemes is of particular importance in the large-scale geological investigations of Azerbaidzan. In the proposed stratigraphic schemes all six stages of the Upper Cretaceous are paleontologically proven and subdivided into different zones which show conciderable persistence in range and areal distribution. Paleontological, geographical, ecological and facial criteria are used in the subdivision. Zones contribute to a better understanding of the subordination of the lithostratigraphic units mapped, in respect of the subdivisions in the European time scale. The Cenomanian Stage is distinctly divided by ammonites and foraminifers, the Turonian - by rudistids and plankton foraminifers. The Coniacian, Santonian and Campanian are distinguished by Inoceramus fauna and foraminifers, the Upper Campanian and Maastrichtian – by cephalopods, echinoids and foraminifers. The studies of the Lesser Caucasus fauna indicate common features with that of the Tethyan geosynclinal provinces. Wide and unbroken connections of the Late Cretaceous Lesser Caucasus basins with the open seas of the Mediterranean determined the Mediterranean type of the Lesser Caucasus complexes. The zonal cheme derived for the Lesser Caucasus is compared and correl ated to other schemes from different regions in the Caucasus.
No abstract is available for this article.
The Ustrem Formation (Lower Triassic) belongs to the Sakar (metamorphic) Triassic. This Triassic type is probably in allochtonous position. It includes the most strongly metamorphosed Triassic rocks in Bulgaria. The Ustrem Formation belongs to the Spathian. A great number of bivalvia prints have been established in marbles, metaquartzites and amphibolites. It is built up of rather varied rocks. They reach up to 2250 min thickness. Main rocks are quartz-mica schists with porphyroblasts of biotite, garnet ±staurolite, marbles and quartz-mica calcitic schists with porphyroblasts of biotite. Metasandsones and amphybolites are secondary rocks. Manganese-ferrous and lead-zink mineralizations are specific formations. The presence of metamorphic quartz veins is characteristic. The Ustrem Formation sediments have undergone regional dynamothermal metamorphism of medium degree (amphibolite facies). The study of the original conditions of sedimentation (protogenesis) allow to be distinguished two main environments – a shallow-water marine environment strongly affected by the dry land and a shallow-water marine environment void of terrigenous influence. Terrigenous-carbonate facies are formed in the first one while the Mramor carbonate buildup grows up in the second one. Both environments are determined by specific paleogeomor phologic conditions.
No abstract is available for this article.
Ten calcareous nannofossil zones are recognized in the sediments of so-called "North European" type of Upper Cretaceous in North Bulgaria: Quadrum gartneri Zone (Lower-Middle Turonian), Eiftellithus eximius Zone (Middle-Upper Turonian), Lucianorhabdus maleformis Zone (Upper Turonian-Lower Coniacian), Micula staurophora Zone (Upper Coniacian-Lower Santonian), Reinhardtites anthophorus Zone (Lower-Upper Santonian), Zygodiscus spiralis Zone (Uppermost Santonian-Lowermost Campanian), Broinsonia parca Zone (Lower Campanian), Ceratolithoides aculeus Zone (Lower-Upper Campanian), Tetralithus trifidus Zone (Upper Campanian-Lower Maestrichtian) and Arkhangelskiella cymbiformis Zone (Lower Maestrichtian). These zones are established on the basis of the stratigraphic distribution of over 30 nannofossil species from the Turonian to the Maestrichtian. The photographs of the stratigraphically important species are made on SEM, TEM and LM.
V. Velev, T. Nenov, S. Popov, S. Jovčev. Main features of neotectonic development and characteristics of the deep geological struсture of Moezian Plate in between Arčar and Osâm Rivers. In course of the diverse study data of tectonic, structural geological and morphological features of principal dividing surfaces in the Mesozoic-Cenozoic section of the area (base and roof of the Jurassic- Paleogene structural-tectonic stage, Preneogene and Quaternary denudational surface) were gathered and analysed. A comparison of the appearing on recent surface fault and photolineament network with seismolineaments in the base of the Jurassic series has shown a partial inheritance of elements: there are similarities in orientation of lineaments, but differences in their frequences. On the other hand, the recent morphostructural features of the Earth surface in general do not reflect the forms of Preneogene relief (including the major ones). Also, they are not linked with the sign of tectonic movements in the earlier stages of tectonic evolution. As inheriting in the recent relief are appearing the old morphostructural and tectonic subjects only, having their own long tectonic life in spite of the not very high dynamic characteristics in general. This authonomy is the most specific of the morphostructural and geostructural plans in the geological development of the studied area in the recent stage.
No abstract is available for this article.
No abstract is available for this article.
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