The Aegeis Region is marked, from a geotectonic viewpoint, with the collision between the African Plate and the Eurasian Plate. The resulting tectogeneses formed the Hellenides and the Aegean arc. The stratigraphic data for the last 23 Ma (the Late Cenozoic) are shown, together with the paleogeographic events, in five sketches: i) Aquitanian; ii) Lljte Burdigalian - Serravalian; iii) Tortonian – Messinian; iv) Pliocene; v) Pleistocene. The·Pleistocene development is of particular interest. The paleogeographic picture at that time did not differ considerably from the present one. Peloponessus was separated from Cythera by a narrow channel which permitted the passage of different mammals.
Creta was a part of the continent during the Late Miocene when the break up of the whole Aegeis began. During the Pliocene, Creta represented an assemblage of small islands, and took its present shape during the Pleistocene when about 12000 years ago a rich endemic fauna was formed. In the same time, Karpathos and Kasos formed a single island (separated from Creta and Rhodos), Rhodos, Kos, Kalymnos and Chios were joined to Asia Minor, and the Cycladic Islands were brought together into two or three big islands.
P. V. Tchoumatchenco, S. P. Cernjavska. The Jurassic System in East Stara Planina. II. Palaeogeographic and palaeotectonic euolution. A reconstruction of the palaeogeographic environment during the deposition of the Lower Jurassic sediments indicates the existence of a turbidite trough infilled with proximal sediments (forming the deep-sea Hadzievdol Fan Delta) and distal basin turbidites. This trough originated as a result of extension during the Pliensbachian and Toarcian. South of it there was a shelf basin bounded on the south by the exotic Zlatarski Ridge. These isopic zones are grouped into a new Early-Middle Jurasic tectonic unit – the Matorids, bordered on the south by the Vardar ocean. The destruction of the Matorids, in conditions of convergence, began during the Aalenian and their main uplift occurred during the Bajocian and in the beginning and the middle of the Bathonian when olistolites of different size were transported into the basin. During the collisional stage, which began in the end of the Bathonian, the areas emerged above sea level – a phenomenon probably related to subduction of the Vardar ocean below the Pontids and their prolongation – the Zlatarski Ridge.
At present, in the area of East Stara Planina, the Jurassic sediments form a long and narrow Austrian tectonic structure – Mator Mts. anticline, with preserved northern, southern or in rare cases – both limbs.
The contribution is accompanied by 4 appendices which describe in detail the Early-Middle Jurassic dynocysts (Dodekova), miospores (Cernjavska) and foraminifers (Trifonova) in the Luda Kamčija Group. Correlations are also made between Kotel Formation and some Upper Cretaceous olistostrome formations in East Stara Planina and Elena-Tvârdica Stara Planina which were incorrectly referred in the past to the Kotel Formation (Sapunov).
This study of the formational nature ot melaso matites from the zones of acid leaching in the Western Srednogorie is based on an integral zonal metasomatic column and on composition-paragenesis diagrams of each zone constructed to follow out the thermodynamic behaviour of components and the reactions between mineralpar ageneses at the zone boundaries. The propylite type of rocks forming aureoles around proper secondary quartzites is not a separate formational unit but belongs to the outermost zone of the secondary quartzite formation.
The physico-chemical analysis of mineral parageneses in the propylite type of rocks shows the equilibria between actinolite, epidote, chlorite, sericite, calcite and magnesite as dependent on temperature and potassium oxide chemical potential. Epidote-chlorite, actinolite-epidote-chlorite and epidote-actinolite parageneses are distinguished as a function of temperature.
The physico-chemical analysis of mineral parageneses in the rocks of inner zones gives the equilibria between quartz, kaolinite, alunite, illite and pyrophyllite as dependent on two of the intensive parameters, namely the chemical potentials of K+, SO42- and H2O, and pH of the mineral-forming environment.
No abstract is available for this article.
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