Petrographic, mineralogical and whole-rock chemistry data from a new outcrop of peralkaline potassic syenite of presumed Variscan age near the town of Shipka, are presented here. The syenites exhibit peralkaline chemistry and very potassic character which markedly differs from nearby situated potassic monzonites, known as Shipka pluton. In spite of the close spatial association of these two bodies, genetic link between them can hardly be supposed. The syenites are composed of K-feldspar, diopside, mica and late interstitial amphibole. Mineral composition reflects the agpaitic conditions of crystallization with formation of sodic amphibole and K-feldspars with important Sr and Ba contents. These rocks have peralkaline wholerock chemistry, very high potassic content and extreme enrichment in LILE, LREE, Th and U. Their trace element signature and isotope characteristics are in favour of derivation from metasomaticaly enriched mantle source.
Twenty six new bone finds of 4 individuals (2 adult and 2 juvenile) have been described and referred to the Late Pliocene kestrel Falco bakalovi Boev, 1999. They came from the species type locality near the town of Varshets (northwest Bulgaria) and demonstrate specific distinguishing from all known falcons of the “tinnunculus” group. They enrich the bone morphology of that falcon covering a large variety of 16 different skeletal elements.
The studied Middle Devonian (Givetian) dolomites occur in three well sections: OP-2 Mihalich, R-119 Kardam and R-1 Vaklino (Northeastern Bulgaria). Two general genetic dolomite groups are distinguished and interpreted on the basis of performed XRD analyses and petrographic observations. The first one is represented by early diagenetic crypto- to microcrystalline dolostones that are characterized by nearly stoichiometric composition (from 51.0 to 51.7 mole % CaCO3) and degree of order ranging from 0.50 to 0.91. They are interpreted as products of rapid precipitation in an arid peritidal (sabkha) environment with hypersalinity of the water milieu and elevated Mg/Ca ratio of the dolomitizing solutions. The second group includes late diagenetic medium crystalline dolostones that have almost stoichiometric composition (from 50.0 to 51.3 mole % CaCO3) and higher degree of order (from 0.77 to 1.18) indicating a possible slow crystallization process and precipitation from dilute solutions at elevated temperatures in an open diagenetic system. A part of them might have also resulted from neomorphic alteration of precursor metastable dolomite phases.
The cordaitaleans are an important plant group in the Westphalian and Stephanian (Bashkirian, Moscovian and Kasimovian) of the Dobrudzha Basin. Small fragments of Cordaites leaves from bore cores are difficult to classify, therefore cuticular analysis has been used in their study. As a result five new species have been erected: Cordaites mogilishtianus, Cordaites makedonkanus, Cordaites dobrudzhanus, Cordaites vraninoensis and Cordaites gurkovoensis. Three species from the Bohemian Massif, namely Cordaites idae, C. schatzlarensis and C. cf. melnicensis also occur in the Dobrudzha Basin. Due to poor preservation, three samples from the Dobrudzha Basin cannot be determined to species and are here described as Cordaites sp. A, Cordaites sp. B and Cordaites sp. C. Most of the Dobrudzha Basin Cordaites belong to the Cordaites cuticular group B (Šimůnek, 2007) which is characterized by single or double stomatal rows on the abaxial cuticle.
The studied coastal karstic system comprises “Selinitsa” Cave and “Drakos” Underground River. It is located in southwestern Greece across the western coastline of the Messinian Mani Peninsula. It is developed into limestones of Upper Senonian to Upper Eocene age belonging to the Mani geotectonic unit. “Selinitsa” is mainly developed above the sea level, whereas “Drakos” is under water down to -48 m. These two caves are now connected through a 28-m long narrow passage at depth of -28 m, thus creating a united karstic system. Both caves were initially separate and terrestrial. Today, the majority of cave passages of “Selinitsa” are terrestrial. In “Senitsa-Drakos” karstic system, sequential karstification base levels have been identified. These levels determined the karstic system development. “Selinitsa” passages are phreatic and vadose, whereas “Drakos” passages are only phreatic, acting as lifting tubes. The passage network of both caves presents dentritic pattern and comprises the hydrological equivalent of the surface drainage network. To the east of the karstic system, karst margin plains are present comprising karstified tectonic terraces, whereas above the “Selinitsa-Drakos” system manmade terraces exist for agricultural purposes.
The number of the symmetry of each crystallographic class (NSCC) includes the sum of the orders of symmetry axes plus the number of symmetry planes plus one for a center of symmetry, if present. In 94.44% of cases, with increasing of NSCC values, the number of monoelement minerals crystallizing in the respective symmetry classes also increases. The density values Dc (gm/Å3) and Dcalc (g/cm3) of the monoelement minerals decrease with the increase of the atomic weight of chemical elements with consecutive or close atomic numbers in the periodic table. The NSCC values show a tendency to decrease with decreasing temperature and pressure of formation of monoelement minerals. At certain NSCC values, the highest the Dc (gm/Å3) and Dcalc (g/cm3) of monoelement minerals, the less probable becomes the possibility their polymorphic forms to be established. Polymorphic modifications denser than α-Fe (having Dc = 4.7049 gm/Å3 and Dcalc = 7.81 g/cm3) have not yet been established. The monoelement polymorphic modifications of As and S, crystallizing in the low symmetry crystal systems, are exceptions to Groth’s law. Most (91.67%) of the monoelement minerals crystallize in the holohedral classes. 2932 of all known 4106 mineral species (71.41%) also crystallize in the holohedral classes of different systems. The data presented suggest that the mineral species in general prefer holohedral classes, having also the highest NSCC values for the respective system. Therefore, the quantitative integral characteristic NSCC is informative in studies of all kinds of mineral assemblages grouped on the basis of different characteristics.
No abstract is available for this publication.
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