The uppermost parts of the Lower Drimos Limestones from the section at Karpenission contain a rich conodont assemblage corresponding to the middle parts of the Sevatian Epigondolella bidentata R. Z. It is dominated by the species Misikella postlzernsteini Kozur & Mock and Paragondolella steinbergensis Mosher, and contains the new conodont species Epigondolella postspatulata Budurov & Mavridis. A rich radiolarian complex has been found too; it contains specific Upper Triassic taxa belonging to Spumellaria and Nassellaria including representatives of superfamily Archecyrtoidea. The foraminiferal assemblage is characterized also by taxa typical of the Upper Triassic.
Red cherts from the base of the overlying cherty interval contain a radiolarian complex of Late Norian – Rhaetian age.
E. P. Vasiliev, A. I. Mel'nikov, V. G. Nikolaev. Structure and evolution of the Baikal Zone. The long-term evolution of the Baikal Zone which is a part of a major geosuture records several stages differing by specific features. The distinctly pronounced endogenic processes during the Early Proterozoic stage played a significant part in the development of the zone. At the end of this stage, the continental crust of the region had been formed. Its further vertical accretion continued during the Riphean, and a mature continental crust already existed at the beginning of the Devonian. The subsequent stage of the evolution was characterized by a tectono-magmatic activization. The Late Paleozoic activization was expressed into formation of numerous zones of superimposed schi stosity and greenschistfacies diaphthoresi s. The weaker Mesozoic activization was represented by thrusts and basalt dykes. During the most considerable Cenozoic activization a system of rift depressions was formed in several successive stages, vertical movements being dominant. Volcanism occurred in several sites and proved to be unrelated directly to grabens although young volcanics have been found in the depressions too (e. g. Tunkin depression). At the present stage the zone is characterized by high seismicity and sedimentation proceeding in the earlier formed depressions.
New radiolarians from the order Nassellaria have been found in Dobridol Formation (Lower Jurassic) of SW Bulgaria, as well as on the territory of the Soviet Union: on Lesser Caucasus (Lower Jurassic) and in Daljniy Vostok (Triassic – Lower Jurassic). Three morphological groups within the superfamily Archecyrtoidea Tikhomirova, 1987, are distinguished with family rank. In the present paper, 28 new species are described. They belong to 14 genera (12 of them also new for the science) referred to Balcaniidae fam. n., Bulgariidae fam. n., and Archecyrtiidae Tikhomirova, 1987. The species described are: Balcanella angulosa sp. n.; Balcanella nana sp. n.; Balcanella Ovoidea sp. n.; Balcanella ussurica sp. n.; Dobridolum calycinum sp. n.; Dobridolum cribellatum sp. n.; Struma ardua sp. n.; Struma decimana sp. n.; Tholusus conoideus sp. n.; Tholusus tumidus sp. n.; Trekljana ampla sp. n.; Trekljana guttiformis s p. n.; Trekljana soluta sp. n.; Trekljana(?) tholiformis sp. n.; Trekljana cf. ampla sp. n.; Zagortchevella declivis sp. n.; Zagortchevella vallaris sp. n.; Bulgarida bojanovi sp. n.; Bulgarida zagortchevi sp. n.; Bulgarida(?) amurensis sp. n.; Guttida trifonfvae sp. n.; Mariella balcanica sp. n.; Mariella petruschevskayae sp. n.; Pyrumella sapunovi sp. n.; Vasiella perrara sp. n.; Vasiella protracta sp. n .; Vesiculla bulgarica sp. n.; Archecyrtum clcukensis sp. n.; Archeeucyrtis primitivum sp. n.
Groundwater in the AI Sinn basin is confined to a carbonate series of Jurassic and Cretaceous age. In the mountainous part of the basin there are more than 200 springs of di scharge ranging from 0.05 dm3/s to 20-30 dm3/s. Three high-discharge springs spout in the coastal part: AI Sinn (8-20 m3/s), Sourit (1-4 m3/s) and Banias (1-3,5 m3/s). Two hydrodynamic horizons are distinguished in the basin: perched water horizon and main aquifer horizon. The numerous small mountain springs drain off the perched water horizon. The three large springs in the coastal plain are fed by the main aquifer. At the beginning of the rainy season (October-November), spring di scharge starts rising with a time lag of 5 to 6 days. Cease of rains (April-May) causes a gradual depletion of spring discharge. In summer, atmospheric condensation replenishes some of the groundwater feeding both the perched water springs and the main aquifer springs. Groundwater level in the main aquifer shows large amplitude variations (up to 200 m). The increasing spring discharge is accompanied by decreasing groundwater mineralization (the latter drops from 700-800 mg /dm3 to 400-500 mg/dm3). The hydrodynamic behaviour of the basin characterizes the area as a purely geosyncline type of karst.
Kh. Khrisclzev, K. Aladgova-Khrischeva. The Middle Eocene deposits in Lukovit syncline as an indicator of tectonic events. A sequence of coarse terrigenous, in places boulder conglomerates over 100 m thick is exposed in the southeastern part of Lukovit syncline. The terrigenous materials is of exotic composition and comprises mainly metamorphic and granitoid rocks which are widespread in Srednogorie zone. The conglomerates overlie and to the north interfinger laterally with a sequence of mica sandstones. The sandstones are composed of disintegration products of the same rocks which make up the fragments of the conglomerates. The sediments of the two sequences lack fo ssil remains. Their Middle Eocene age is indirectly determined on the basis of their normal position (without breaks) over faunistically proven rocks referred to the lowermost parts of the Middle Eocene.
The local development of exotic terrigenous rocks so far to the north (in the Transitional zone) may be explained by destruction and deposition of material from the Srednogorie zone, transported to the north as a gravity thrust. This event took place in the Middle Eocene.
No abstract is available for this article.
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