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Articles 2281 - 2310 of 3859

Full-Text Articles in Physical Sciences and Mathematics

The Separation And The Concentration Of Minerals From The Zeolitic Volcanic Tuffs. Analytical Composition, Dumitru Bulgariu Mar 2012

The Separation And The Concentration Of Minerals From The Zeolitic Volcanic Tuffs. Analytical Composition, Dumitru Bulgariu

Studia UBB Geologia

The separation and concetration of minerals from zeolitic volcanic tuffs represent one of the problems for which the literature not offer, to much practically solutions. The experimental strategy used by as, for the separation minerals from zeolitic volcanic tuffs to comprise the following methods: heavy liquids separation; magnetic separation and electrophoresis separation. For zeolites, silica polymorphs, feldspars and other minerals separated from zeolitic volcanic tuffs, the work eighth conditions and the proper experimental strategy efficiency has been estabilish. The purity for mineral fractions can be separated has been between 95.0 – 99.6 %.

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Characterisation Of Some Clays Used For Whiteware Ceramics I. Mineralogical Composition, Marcel Benea, Maria Gorea Mar 2012

Characterisation Of Some Clays Used For Whiteware Ceramics I. Mineralogical Composition, Marcel Benea, Maria Gorea

Studia UBB Geologia

In order to obtain a semiquantitative mineralogical composition of raw materials used for whiteware ceramics, four different clay types were analysed by X-ray diffraction. Studies were carried out by using a combination of analyses of the bulk sample, and of the fine fraction. Using a well-established pre-treatment methodology (use of chemicals, ultrasonic treatment, dispersion procedures), clay mineral concentration by centrifugation and sedimentation, oriented and random powder preparation, cation saturation, expansion/dehydration methods, 12 X-ray diffractometer traces were obtained from each sample. Based on these informations it was possible to establish the qualitative mineralogical composition, and also a semiquantitative one using peak …

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Profesorul Razvan Givulescu La 80 De Ani, Iustinian Petrescu Mar 2012

Profesorul Razvan Givulescu La 80 De Ani, Iustinian Petrescu

Studia UBB Geologia

No abstract provided.

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Middle Miocene (Badenian) Conidae From Lapugiu De Sus, Romania: Systematical And Palaeoecological Data, Carmen Chira, Ileana Voia Mar 2012

Middle Miocene (Badenian) Conidae From Lapugiu De Sus, Romania: Systematical And Palaeoecological Data, Carmen Chira, Ileana Voia

Studia UBB Geologia

The paper presents in synthesis the conids from Lăpugiu de Sus, especially those which are preserved in the collections of Palaeontology-Stratigraphy Museum of the Babeş-Bolyai University. Conids, carnivorous gastropods who lived in shallow waters from neritic zones, in warm seas, respectivelly subtropical to tropical, with a normal salinity, have been the most diversified gastropods at Lăpugiu de Sus during the Middle Miocene (Badenian). There are also species which could tolerate slight decreasing of salinity such as Conus (Conolithus) dujardini brezinae. It was remarked that the conids from Lăpugiu de Sus lived in the conditions of shore-offshore zones where the temperature …

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The Badenian Calcareous Nannoplankton From Turda And Ocna Dej Mines (Transylvanian Basin, Romania), Carmen Chira Mar 2012

The Badenian Calcareous Nannoplankton From Turda And Ocna Dej Mines (Transylvanian Basin, Romania), Carmen Chira

Studia UBB Geologia

Middle Miocene (Middle Badenian, respectivelly Wielician) clays interlayered with the salt deposits from Turda and Ocna Dej salt mines of the Transylvanian Basin have been analysed. The assemblages of calcareous nannoplankton/nannofossils and their significance are presented. Nannofloras are scarce and poorly preserved. The fossil index for NN5 Zone – Sphenolithus heteromorphus appears very rarely, only in few samples. The assemblages can be considered to belong to the upper part of the NN5 Zone and also to the lower part of the NN6 Zone.

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A Paleoecological Reconstruction Of The Late Glacial And Holocene Based On Multidisciplinary Studies At Steregoiu Site (Gutai Mts., Romania), Angelica Feurdean, Leif BjöRkman, Barbara Wohlfarth Mar 2012

A Paleoecological Reconstruction Of The Late Glacial And Holocene Based On Multidisciplinary Studies At Steregoiu Site (Gutai Mts., Romania), Angelica Feurdean, Leif BjöRkman, Barbara Wohlfarth

Studia UBB Geologia

High resolution analyses of pollen, mineral magnetic properties, loss of ignition, lithostratigraphy and AMS 14C measurements of lake sediments and peat deposits accumulated in the former crater lake of Steregoiu (Gutâiului Mts., NW Romania), gave new and important information about vegetation and climate changes from the period GS-2 to the present. During the Lateglacial, three cold events were recorded: before 14,700 cal. years BP (GS-2), 14,050–13,800 cal. years BP (GI-1d), 12,900-11,500 cal. years BP (GS-1), and a warm climatic event between 13,800-12,950 cal. years BP (GI-1c to GL-1a). The Late Glacial/Holocene transition around 11,500 cal. years BP, was determined by …

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Wielician Foraminifera At The Western Border Of The Transylvanian Basin, Sorin Filipescu Mar 2012

Wielician Foraminifera At The Western Border Of The Transylvanian Basin, Sorin Filipescu

Studia UBB Geologia

Marine Middle Miocene deposits at the top of Gârbova de Sus Formation preserve a particular foraminifera assemblage, with both benthic and planktonic taxa. Presence of several biostratigraphic significant species allowed an extension of the known age of the formation, up to Wielician. The morphogroups also suggest a deeper environment, compared to the rest of the formation. The change of fauna type at this level might be correlated to the start of a new global cycle.

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The Spatial Extension And The Age Of The Tomnatec Formation In Audia Nappe, Liviu Ionesi, Florin Florea Mar 2012

The Spatial Extension And The Age Of The Tomnatec Formation In Audia Nappe, Liviu Ionesi, Florin Florea

Studia UBB Geologia

No abstract provided.

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Palynological Researchers Concerning The Pontian On The Visenilor Valley And Boereasca Valley - Ne Of Drobeta Turnu Severin (Sw Romania), Iustinian Petrescu, Nicoleta Bican-Brișan, Cornel Meilescu, Ion PăTruțoiu Mar 2012

Palynological Researchers Concerning The Pontian On The Visenilor Valley And Boereasca Valley - Ne Of Drobeta Turnu Severin (Sw Romania), Iustinian Petrescu, Nicoleta Bican-Brișan, Cornel Meilescu, Ion PăTruțoiu

Studia UBB Geologia

Palynological analyses in the sections of Vişenilor Valley and Boereasca Valley (Upper Pontian (Bosphorian)) are presented in table 1. In the second part of paper, the authors made a comparison between microflora from Mehedinţi and other Pontian microfloras in Romania and from abroad (former Yugoslavia, Hungary, and Slovakia).

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Upper Jurassic And Lower Cretaceous Sedimentary Formations From The Valcan Mountains (South Carpathians), Grigore Pop, Ioan I. Bucur Mar 2012

Upper Jurassic And Lower Cretaceous Sedimentary Formations From The Valcan Mountains (South Carpathians), Grigore Pop, Ioan I. Bucur

Studia UBB Geologia

The litho- and biostratigraphy of the Upper Jurassic-Lower Cretaceous formations cropping out in the southwestern part of Vâlcan Mountains is presented. Five formations were recognised in the studied area: Valea Pragurilor Formation, Valea Cheii Formation, Topeşti Formation, bioclastic-oolitic limestones from Sudoieşi valley and Izvarna Formation. The age of these formations is mainly based on foraminifera and calcareous algae.

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Aspects Of Romanian Early Jurassic Palaeobotany And Palynology. Part Iv. A New Species Of Weltrichia From Anina, Mihai E. Popa Mar 2012

Aspects Of Romanian Early Jurassic Palaeobotany And Palynology. Part Iv. A New Species Of Weltrichia From Anina, Mihai E. Popa

Studia UBB Geologia

A new species of bennettite genus Weltrichia BRAUN, Weltrichia givulescui n.sp., is defined, described and discussed. Its age is Sinemurian and it was recorded associated with Zamites aninaensis foliage from Anina, South Carpathians, Resita Basin, where these species are confined to the upper sandstone sequences of the Valea Tereziei Member, Steierdorf Formation, between the Coal seams no. 6 and 8.

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Liotia Ornata N.Sp. (Mollusca, Gastropoda) From Badenian Of Borod Basin (Nw Romania), Mirela Popa Mar 2012

Liotia Ornata N.Sp. (Mollusca, Gastropoda) From Badenian Of Borod Basin (Nw Romania), Mirela Popa

Studia UBB Geologia

A new small-sized gastropod species was identified in Badenian deposits (Borod Formation) in the eastern part of Borod Basin (west of Apuseni Mts.), and was described in this study under Liotia ornata n. sp.

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Coralgal Facies Of The Upper Eocene-Lower Oligocene Limestones In Letca-Rastoci Area, Ioana Prica Mar 2012

Coralgal Facies Of The Upper Eocene-Lower Oligocene Limestones In Letca-Rastoci Area, Ioana Prica

Studia UBB Geologia

In this paper are described the coralgal facies identified in the Upper Eocene-Lower Oligocene limestone succession (Cozla Formation) outcropping in two quarries at Letca and Rastoci (Sălaj district, Romania). In the studied profiles the coral and algae limestones are interlayered with bioclastic limestones with foraminifera. On the top of relatively deep water deposits, coral and algae crusts and dendritic corals coated by algae were deposited. The environment registered a gradual deepening, the deposits being completely immersed, while bioclastic limestones with foraminifera were recurrently formed. This cycle is repeated, the whole succession being caracterized by several such “parasequences”.

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Microfacies And Microfossils In Upper Jurassic Limestones From Cheile Turenilor, Emanoil SăSăRan, Ioan I. Bucur, Ioana Prica Mar 2012

Microfacies And Microfossils In Upper Jurassic Limestones From Cheile Turenilor, Emanoil SăSăRan, Ioan I. Bucur, Ioana Prica

Studia UBB Geologia

In the Cheile Turenilor (Tureni Gorges) area, a carbonate succession about 150 m thick developed on top of island arc magmatites. It mainly consist of gravity - induced deposits (debris flows, mass flows and grain flows). Coral, sponges and stromatoporoid bioconstructions are associated. Microbolites play an important role, as binders of the intraclastic rudstones/ grainstones facies, as well as of the incorporated corals, sponges, stromatoporoids, bryozoans, molluscs.

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Contributions To The Knowledge Of Flora And Vegetation Of The Tertiary In The Extracarpathian Area Of Romania, RăZvan Givulescu Mar 2012

Contributions To The Knowledge Of Flora And Vegetation Of The Tertiary In The Extracarpathian Area Of Romania, RăZvan Givulescu

Studia UBB Geologia

The author presents the fossil flora and vegetation of the extracarpathian regions of Romania: on one hand, the Eocene-Oligocene-Late Dacian fossil floras from the southern area, and on the other hand - the Sarmatian ones from the eastern area. It is insisted on the Sarmatian as compared to the one from Transylvania. There are important similarities with the southern area, but none as concerns the eastern one. The characteristic feature of the area comprised between the Carpathians and the Prut is the absence of the Lauraceae and the massive presence of Betulaceae. The author suggests the creation of a palaeofitogeographic …

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Genesis Of Magmatic Derived Ore Deposits. 4 – Hydrothermal Metallogeny (Geneza Zăcămintelor De Origine Magmatică. 4 – Metalogenia Hidrotermală), CăLin G. TăMaș Mar 2012

Genesis Of Magmatic Derived Ore Deposits. 4 – Hydrothermal Metallogeny (Geneza Zăcămintelor De Origine Magmatică. 4 – Metalogenia Hidrotermală), CăLin G. TăMaș

Studia UBB Geologia

No abstract provided.

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Sedimentologie - Petrologie (Culegere De Lucrări Ştiinţifice), Ioan MâRza Mar 2012

Sedimentologie - Petrologie (Culegere De Lucrări Ştiinţifice), Ioan MâRza

Studia UBB Geologia

No abstract provided.

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Contributions To The Study Of The Alluvial Gold From Valea Pianului Area (Alba District), Horea Bedelean, Aura Bedelean Mar 2012

Contributions To The Study Of The Alluvial Gold From Valea Pianului Area (Alba District), Horea Bedelean, Aura Bedelean

Studia UBB Geologia

Pianu de Sus area (Alba district) is located in the north-eastern part of the Sebeş Mountains. The region consists of metamorphic (Sebeş-Lotru group), magmatic (granites and quartziferous porphyries and pegmatites) and sedimentary deposits (Senonian, Neogene and Quaternary age). Granulometric studies, separations of the heavy fractions, optic and electronic microscopic investigations were performed on the alluvial deposits and detritic sedimentary formations. The analysed gold shows tipical morphology for two grains types: primary and secondary. From a chemical point of view was evidenced electron microprobe The chemical analyses, performed by using electron microprobe, shows a high amount of gold and silver.

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Using The Pollution Index To Characterize The Level Of Contamination Of The Aries River (Apuseni Mountains) (In Romanian), Forray Ferenc Lázár Mar 2012

Using The Pollution Index To Characterize The Level Of Contamination Of The Aries River (Apuseni Mountains) (In Romanian), Forray Ferenc Lázár

Studia UBB Geologia

In the present study we try to use a new index called "pollution index" for define the pollution level of river using the dissolved heavy metal concentrations. This index derives from Müller’s geoaccumulation index but use the dissolved metal concentrations. The river water samples collected between the municipalities of Cheia and Muncel along a 54-km stretch of the Aries River (NW Romania) were analysed by capillary electrophoresis for heavy metals. The primary results show that pollution index can be used for determination of pollution level of river in base of dissolved heavy metal concentration as is confirmed also by factor …

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Carbon And Oxygen Isotope Ratios In Rona Limestone, Romania, Stela Cuna, Dana Pop, Alexandru Hosu Mar 2012

Carbon And Oxygen Isotope Ratios In Rona Limestone, Romania, Stela Cuna, Dana Pop, Alexandru Hosu

Studia UBB Geologia

The carbon and oxygen isotopic compositions of limestones provide criteria for the evaluation of the depositional environment. For Jurassic and younger samples, the best discrimination between marine and fresh-water limestones is given by Z parameter, calculated as a linear correlation between δ13C and δ18O (‰ PDB). Rona Limestone (Upper Paleocene - Lower Eocene), outcropping on a small area in NW Transylvania (Meseş area) is a local lacustrine facies. There, it divides Jibou Formation into the Lower Red Member and the Upper Variegated Member, respectively. Recently, a sequence containing a marine nannoplankton assemblage was identified in the base of Rona deposits. …

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Historical, Geological, And Mining Benchmarks Concerning The Endogeneous Breccia Structures Associated With The Neogene Magmatic Events In Romania (In Romanian), CăLin G. TăMaș Mar 2012

Historical, Geological, And Mining Benchmarks Concerning The Endogeneous Breccia Structures Associated With The Neogene Magmatic Events In Romania (In Romanian), CăLin G. TăMaș

Studia UBB Geologia

An up-to date exhaustive bibliographic study is presented in order to highlight the evolution of the knowledge of endogenous breccias related to Neogene magmatism from Romania during the 19th and 20th centuries. This approach is based mainly on Romanian literature but there are also several foreign citations. Instead of the general opinion (widespread among Romanian mining companies) according to which the occurrence of the breccia structures in Romania is scarcely, this paper show the ubiquitous presence of breccia pipe and breccia dyke structures among the Neogene ore deposits from Romania, in Apuseni Mountains as well as in Eastern Carpathians.

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New Data On The Volcanic Tuff From Petrestii De Jos (Cluj District), Horea Bedelean, Ioan Ivan, Dana Pop, Ioan Bedelean, Gheorghe Pleșoiu Mar 2012

New Data On The Volcanic Tuff From Petrestii De Jos (Cluj District), Horea Bedelean, Ioan Ivan, Dana Pop, Ioan Bedelean, Gheorghe Pleșoiu

Studia UBB Geologia

The present study was carried out on the cineritic interlayers from Petreştii de Jos (closed quarry from Indolului Valley), in order to present their detailed mineralogical-petrographical features. Previous work already noticed the similarity of this tuff level with Dej Tuff Complex in other areas. The studied outcrop consists of a compact volcanic tuff interlayered with marls and tuffaceous clays. The analytical investigations: chemical analyses, X-ray diffraction, IR spectroscopy and electron microscopy reveal the nature of the diagenetic transformations dominated by zeolitization. Besides clinoptilolite, which is the typical zeolite for Dej Tuff from the Transylvanian Depression, our investigation evidenced also the …

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Geochemical Considerations Upon The Banatites From Budureasa-Pietroasa Area (Apuseni Mountains, Romania), Corina Ionescu, Nicolae Har Mar 2012

Geochemical Considerations Upon The Banatites From Budureasa-Pietroasa Area (Apuseni Mountains, Romania), Corina Ionescu, Nicolae Har

Studia UBB Geologia

Various methods (T.A.S., Irvine and Baragar, Maniar and Piccoli, and Pearce diagrams) were used for the characterization of the Budureasa-Pietroasa banatites. The global geochemical characteristics of the rocks are in good agreement with the general features of the banatites, however showing some peculiar differences.

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Tuffaceous Conglomerates: Syn-Eruptive Resedimented Debris Flow And Hyperconcentrated Flow Deposits From The "Rhyodacitic Formation", Gutai Mountains, Eastern Carpathians, Alexandrina FüLöP Mar 2012

Tuffaceous Conglomerates: Syn-Eruptive Resedimented Debris Flow And Hyperconcentrated Flow Deposits From The "Rhyodacitic Formation", Gutai Mountains, Eastern Carpathians, Alexandrina FüLöP

Studia UBB Geologia

The first volcanic products from Gutâi Mts, Eastern Carpathians belong to the "Rhyodacitic Formation". The physical constituents of this formation are as follows: pyroclastic deposits (ignimbrites and fall tuffs), syn-eruptive resedimented volcaniclastic deposits, volcanogenic and non-volcanogenic sedimentary deposits. The tuffaceous conglomerates belong to the syn-eruptive resedimented volcaniclastics and represent the coarsest deposits. They outcrop in Băiţa area, west from Baia-Mare, being underlain by Lower Badenian (15.4±0.6 Ma) ignimbrites and overlain by Lower Sarmatian claystones. The main components of the conglomerates are boulders and cobbles of sedimentary and metamorphic rocks in a tuffaceous matrix. Scarse blocks eroded from the lower ignimbrite …

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Studies On Aries River (Apuseni Mountains) Pollution Using Factorial Analyses (In Romanian), Forray Ferenc Lázár Mar 2012

Studies On Aries River (Apuseni Mountains) Pollution Using Factorial Analyses (In Romanian), Forray Ferenc Lázár

Studia UBB Geologia

In the present study we try to use factor analysis in the characterisation of river water chemistry between the municipalities of Cheia and Muncel along a 54-km stretch of the Aries River (NW Romania). The results show that 4 factors can explain 88% of the water chemistry. The first factor explains 39% of the total data variance, and represents the water-rock interactions. This high percent indicates the importance of water rock interactions in defining the chemistry of surface waters. The second factor explains 23% of the data variation and represents the influence of mining effluents. The influence of the mine …

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The Hardness Of Synthetic Products Obtained From Cooled And Crystallized Basaltic Melts (In Romanian), Daniela Ogrean Mar 2012

The Hardness Of Synthetic Products Obtained From Cooled And Crystallized Basaltic Melts (In Romanian), Daniela Ogrean

Studia UBB Geologia

The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes) indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Timiş district) and between 539–958 respectively, in case of the Racoş basalts (Braşov district). There is a certain variation of the hardness within the same sample, in various measurement points, within …

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A Possible Evolutionary Model Of The Apuseni Mountains And Of The Biharia Nappe System (In Romanian), Rodica Stan, Adrian Puște Mar 2012

A Possible Evolutionary Model Of The Apuseni Mountains And Of The Biharia Nappe System (In Romanian), Rodica Stan, Adrian Puște

Studia UBB Geologia

A Possible Evolutionary Model of Apuseni Mountains and of Biharia Nappe System. Our intention is to expose and outline a possible structural model for the Paleozoic evolution of the Apuseni Mountains and for the alpine evolution of some tectonic units belonging to the Biharia Nappe System. During the Paleozoic times, the tectonic units involved in this model migrated from the northern margin of Gondwana toward Laurasia, then collided in Variscan orogeny. The Biharia and Codru Nappe Systems were sheared from the Preapulian craton margins, and the Transylvanides were sheared from the Penninic rift, during the Alpine orogeny.

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Tectonic Problems In The Western Part Of Padurea Craiului Massif (Apuseni Mountains) (In Romanian), Ioan Balintoni, Adrian Puște Mar 2012

Tectonic Problems In The Western Part Of Padurea Craiului Massif (Apuseni Mountains) (In Romanian), Ioan Balintoni, Adrian Puște

Studia UBB Geologia

Tectonic Problems in the Western Part of Pădurea Craiului Massif (Apuseni Mts.). Pădurea Craiului Massif belongs to Bihor Unit. The Codru Nappe System overthrusts its South-Western margin. The structures generated in the nappes front, such as folds, faults, fisures, cleavages, suggest a movement direction from South-West toward North-East. This direction differs with 90° relative to transport direction of Biharia Nappe System. The mentioned structures represent a prove for origin of Codru Nappe System from the Meliatic margin of Preapulian Craton.

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Late Quaternary Palaeoclimate Reconstruction Based On Clay Minerals Assemblage From Preluca Tiganului (Gutai Mountains, Romania), Lucreția Ghergari, Bogdan P. Onac Mar 2012

Late Quaternary Palaeoclimate Reconstruction Based On Clay Minerals Assemblage From Preluca Tiganului (Gutai Mountains, Romania), Lucreția Ghergari, Bogdan P. Onac

Studia UBB Geologia

Several core samples were extracted from the overgrown crater lake of Preluca Tiganului, NW Romania. The overall lithology and the mineral assemblages (mostly clay) described from different levels within these cores, suggest three main periods having humid or dry conditions. Based on these findings, palaeoclimate conditions can be reconstructed the over the time period spanning 15,000 to 13,500 cal. years BP.

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Structural Researches In The Eastern Carpathians (In Romanian), I. Balintoni, U. Baier Mar 2012

Structural Researches In The Eastern Carpathians (In Romanian), I. Balintoni, U. Baier

Studia UBB Geologia

Structural Researches in the Eastern Carpathians. The Alpine mesoscopic lineations in the East Carpathians metamorphics, are NW-SE orientated. A few lineations, nearly E-W orientated, could be proved as pre-Alpine in age. Within the Ditrău Massif, is conserved a pre-Alpine attitude of foliations, as frozen magmatic flow, along the metamorphic pre-Triassic fabric. The lineation directions were conditioned by the Cretaceous-Tertiary contractional elimination of the External Carpathian Flysch Basin.

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