Ioan Mac , then continued with prof. The chain has a general northwesterly trend from Mount St. Tr XII sess. Contactul liniar aparent abrupt, cu corneenele de pe rama SW a masivului este tectonic Seghedi, n Savu et al. Cimentul clastelor poate fi calcit, silice sau sulfati.

Autohton2. Diferitele modificatii se noteaza cu a g si cristalizeaza in sisteme cristalografice diferite. Intensitatea a.

Calitatea si structura scoartei de a. Scoarta de a. Granulometric, a. Textura a. Corpurile a. Optic, corpurile a. Din p. Intensitatea proceselor fizice compactizare, recristalizare si chimice solubilizari, cimentari, substitutii suferite de sedimente sunt in functie de grosimea si de timpul scurs de la ingropare sub dep. Termenul a fost introdus de Grabau in Cristalele a. In Romania, apare asociat cu gipsul in dep.

CaAl2Si2O8, s.

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Sub aceasta compozitie se intalneste accidental in natura. Apare in geode, in rocile magmatice foarte bazice si in unele filoane de tip alpin. Este utilizat ca fondant in fabricarea portelanului; 2. An – oligoclaz, An – andezin, An – labrador, An – bytownit. Sunt dificil de identificat in structurile sedimentare vechi.

In Romania, se gaseste la Schela-Gorj. In Romania, se gaseste in roci variate: s. Format, in special, prin procese chimice de sedimentare in medii dulci-cole, saline si hipersaline.

In Romania, este legat de unele procese hidrotermale la Baiut, Corund, Sacaramb sau de depuneri din izvoare bicarbo-natate la Turia, Covasna, Toplita. Utilizat pentru confectionarea unor obiecte ornamentale. Gheorghe Oaie si un vulcanolog dr. Alexandrina Fulop. Cadrul geologic si structural Din punct de vedere geologic, Parcul National Muntii Macinului se situeaza in orogenul norddobrogean, orogen care constituie o zon deformat chimeric Mrazec,Murgoci,situat n forlandul carpatic ntre platformele Moesic i Scitic Dumitrescu, Sndulescu, Dobrogea de Nord reprezint zona de aflorare a orogenului, n timp ce Promontoriul nord-dobrogean constituie o creast ngropat, ce se afund la adncimi din ce n ce mai mari sub sedimentele neogene ale Depresiunii Getice i ale pnzelor Carpailor Orientali.

Zircon dating de accretion crustal oceanic hercinic afloreaza n special in partea vestica a Dobrogei de Nord zona Mcinfiind puternic ridicat pe falii de incalecare chimerice la unghi mare. Contactul dintre zona Macin si zona Tulcea are loc de-a lungul fracturii Luncavita-Consul, o falie inversa la unghi mare, de-a lungul careia roci granitoide si metamorfite de Boclugea ale fundamentului pre-triasic incaleca spre est depozitele triasice ale Formatiunilor de Somova, Niculiel si Alba.

Fundamentul depozitelor mezozoice din unitatea de Mcin const din formatiuni metamorfice seriile de Orliga, Megina, Boclugea si Gnaisele de Meginadepozite paleozoice anchimetamorfice Formatiunile de Cerna, Bujoare si Carapelit si roci granitoide si filoniene paleozoice fig 2, 3. Fundamentul pre-triasic este strbtut de o suit de dyke-uri de bazalte si riolite, reprezentnd un magmatism bimodal legat de miscrile extensionale de la nceputul riftogenezei triasice.

Diversitatea geologica Desi ocupa o suprafata relativ restransa, Parcul National Muntii Macinului prezinta mare o diversitate geologica, datorita unei constitutii litologice extrem de variate si unei structuri complexe, reprezentand rezultatul insumat al etapelor tectonice hercinica si alpina timpurie chimerica. In cuprinsul Parcului afloreaza sisturi cristaline cu metamorfism de grad mediu sau scazut amfibolite, micasisturi, metariolite si metatufuri acide, cuartite, filite, etc.

POP, N. Studiu de caz: Ţara Beiuşului judeţul Bihor L.

Structurile hercinice ale formatiunilor sedimentare paleozoice, in parte obliterate de deformarile mai noi, mai pot fi recunoscute in diferitele unitati structurale chimerice. Tectonica hercinica in panze de sariaj, care a transportat sisturile cristaline peste formatiunile paleozoice cu metamorfism incipient, poate fi reconstituita in cadrul unitatilor alpine timpurii, care reprezinta cute-solz marginite de incalecari la unghi mare.

Relieful si peisajul geomorfologic sunt controlate atat litologic, cat si tectonic, ceeace subliniaza importanta rolului geodiversitatii in cadrul acestui parc, care reprezinta, de altfel, un laborator in aer liber pentru studiul proceselor geologice.

Coloane litologice ale formatiunilor din unitatea de Macin Formatiuni paleozoice Depozitele paleozoice alcatuiesc doua centuri de ardezii slate belt alungite pe directia NW-SE.

Fasia mai lata, estic, const predominant din depozite clastice ale Formatiunii de Carapelit; iviri restranse de depozite siluriene apar n dealurile Pietrele Albe din zona Megina si n dealul Cracanelor din Promontoriul Bugeac. Depozitele paleozoice au suferit un metamorfism regional hercinic de grad foarte scazut anchimetamorfism.

Formatiunea de Cerna Succesiunea Formatiunii de Cerna, cel mai bine deschisa pe versantii vestici ai dealurilor Priopcea si Dalchi Bair, cuprinde un orizont inferior de calcare negre-cenusii, cu pirita si un orizont superior de ardezii cenusii; calcarele contin o intercalatie de silicolite negre n Curt Bair, iar ardeziile din Chior Tepe, Ormangic Bair, Pepiniera si de pe versantul vestic al Priopcei, la est logiciel dating soseaua Mcin-Cerna, prezinta intercalatii de gresii cuartoase-muscovitice si calcare cafenii galbui cu rare resturi organice, traversate si de forajul Cutarea stransa a depozitelor, cu cute de flanc si cute cu dublu plonj, nu permite aprecierea grosimii reale a termenilor.

Studiul petrografic, corelat cu datele litologice, sugereaza c Formatiunea de Cerna reprezinta depozite pelagice sau hemipelagice; nivelele subtiri de calcare cu bioclaste de crinoide provin din biomicrite depuse n ape mai putin adanci, iar orizontul de calcare negre, bogate n pirita si substanta organica, s-a format intr-un mediu euxinic.

Intercalatiile de gresii si siltite indica aporturi terigene episodice datorate furtunilor tempestite. Formatiunea de Cerna a fost atribuita Silurianului pe baza unor resturi de macrofauna Simionescu, ; Mirut, Mirut, Contactul estic cu metamorfitele seriei de Boclugea este tectonic n dealurile Priopcea si Dalchi Bair.

Limita vestic, cu depozitele Devonian inferioare ale Formatiunii de Bujoare, este marcata de aparitia conodontului Icriodus woschmiedti, n calcarele cafenii intercalate n ardeziile de pe versantul vestic al Priopcei.

Prin urmare, limita dintre cele doua formatiuni se afla n cuprinsul orizontului de ardezii si este imposibil de trasat n absenta unor profile biostratigrafice continui, corelate cu datele structurale.

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Formatiunea de Bujoare Devonianul zonei Mcin se dezvolt n facies renan. Principalele tipuri litologice au fost grupate n doi termeni ai Devonianului inferior, reprezentand Geddinianul si Coblenzianul.

Geddinianul cuprinde un orizont de calcare albe si cenusii, mai mult sau mai putin recristalizate, dispus peste o succesiune de gresii cuartitice n alternanta cu ardezii cenusii si calcare maronii crinoidale, ce contin conodontul Icriodus woschmidti. Coblenzianul este alcatuit dintr-o succesiune de strate discontinui de gresii cuartitice, ardezii negre, gresii calcaroase si calcare crinoidale. Varsta coblenziana rezulta din prezenta unei faune dominate de brachiopode, semnalata prima oara de Cadere si Simionescu Desi cornificate, depozitele din dealul Bujorul Bulgaresc contin o bogata fauna de branchiopode, crinoide si tentaculiti, n care trilobitii, coralii, briozoarele si ostracodele sunt subordonate Iordan, Fauna formeaza frecvent lumasele si indic un mediu bentonic de self deschis.

Faciesul depozitelor devoniene corelat cu caracterele petrografice ale gresiilor intercalate, sugereaza deasemenea depozite marine de apa putin adanca. Formatiunea de Carapelit Formatiunea de Carapelit cuprinde depozite continentale discordante pe fundamentul hercinic, ce remaniaza granite si roci metamorfice. Principalele asociatii litofaciale ale Formatiunii de Carapelit cuprind: depozite cenusii aluviale, depozite rosii facies de red-bed - Gresia rosie de Martina; faciesul vulcano-sedimentar.

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Faciesurile sunt partial izocrone. Depozitele cenusii aluviale cuprind succesiuni grosiere de con aluvial dominate de conglomerate si succesiuni de cmpie aluvial gresii-siltite Seghedi, Oaie, Harta geologica simplificata a unitatii de Macin, cu localizarea PNMM Gresia rosie de Martina, bine dezvoltata pe Valea Martina si in dealul lui Mos Deliu, este o secventa de progradare mai grosiera spre top, cuprinzand gresii cu stratificatie paralela si incrucisata ce trec n sus la conglomerate, interpretate c depozite fluviatile de rau despletit braided Oaie, Faciesul vulcanosedimentar include depozite piroclastice ignimbrite, tufuri de cadere, depozite de val piroclastic, tufuri cu lapili acretionariinterstratificate cu grosimi variabile si la diferite nivele n coloana litologica cu depozite epiclastice conglomerate, gresii si siltite verzui, rosii sau cafenii si cu argilite rosii si verzi Seghedi et al.

Datele petrografice indica evolutia n timp a sedimentarii de la terigena la vulcanogena si epiclastica Oaie, Seghedi,intr-un regim tectonic de arc magmatic de margine continentala Seghedi, Oaie,cu depunerea materialului detritic intr-un bazin back-arc ensialic retroarc Seghedi, Oaie, Varsta Formatiuniii de Carapelit, practic nefosilifera, a fost un subiect controversat, ea fiind atribuita Permo-Carboniferului Mrazec, Pascu, ; Rotman,Carboniferului Cantuniari,Carboniferului inferior - Devonianului superior Murgoci, ; Macovei, si Carboniferului inferior Mirut, Mirut, Singura fosil descoperit n Formatiunea de Carapelit este un rest de plant identificat drept Calamaria Paeckelman,Asterocalamites Atanasiu, sau Archaeocalamites Macovei,genurile indic intervale de timp de vrste diferite - fie Carbonifer superior, fie Devonian superior - Carbonifer inferior.

In roci pelitice din dealurile Carapelit si Conaciu au fost identificate acritarche, spori trileti, chitinozoare, scolecodonte si microspori Vaida, n Seghedi et al. Continutul paleontologic srac si foarte slab conservat este cu sigurant remaniat.

Perioada Cambriană - Mediul Cambrian

Petrografia termenilor terigeni grosieri, datele palinologice din nivelele pelito-siltice si microfauna din calcarele remaniate n conglomerate indic c Formatiunea de Carapelit este cert postdevonian. Din cele prezentate rezult c vrsta acestei formatiuni este cuprins n intervalul Carbonifer Permian mediu.

Ea este mai veche decat rocile masivului Greci care o strabat si cornifica, si pentru care s-a obtinut o varsta izocrona Rb-Sr de milioane de ani Permian superior Pop et al. Pe baza acestor elemente, corelate cu faciesul de red-beds si cu prezenta vulcanismului ignimbritic, s-a considerat c Formatiunea de Carapelit s-a depus n intervalul Carbonifer superior-Permian inferior Oaie, Seghedi, In cuprinsul Dobrogei de Nord afloreaza magmatite hercinice si alpine.

Ele reprezinta un magmatism calcoalcalin de margine de placa activa, format n conditiile unui arc magmatic de margine continentala. Pe rama nordic si sud-vestic a Dobrogei de Nord, fundamentul pretriasic este strbtut de roci magmatice alcaline: la sud de falia Sfntu Gheorghe, se dezvolt un vulcanism alcalin-subalcalin bimodal, formnd o suit de dykeuri orientate E-W ce strbat paleozoicul de tip Tulcea; pe rama sud-vestic a unittii de Mcin, apar granitoide si riolite alcaline, Magmatitele alpine s-au format n Permianul superior, Triasic si Jurasicul superior, n conditii geotectonice diferite: magmatism alcalin pe rama nordic si sud-vestic a unittii de Mcin magmatism intraplaca legat de initierea riftogenezei triasice ; vulcanism bimodal formand suite de dykeuri bazice si acide ce strabat fundamentul pre-alpin din partea centrala si nord estic a unittii de Mcin; vulcanism bimodal interstratificat n depozitele de platforma carbonatica Jurasic superioare din partea sudic a unittii de Mcin tufuri riolitice si curgeri de lave bazice.

Vulcanite calcoalcaline paleozoice Manifestarile vulcanice hercinice foarte probabil Permian inferioare din unitatea de Mcin reprezinta un vulcanism riolitic calcoalcalin Seghedi et al. Vulcanismul hercinic a produs n principal roci piroclastice si doar local curgeri de lave Seghedi et al.

Dintre rocile piroclastice, predomina cantitativ ignimbritele; tufurile de cadere, tufurile de val piroclastic cu stratificatie incrucisata si tufurile cu lapili acretionari fiind mai reduse c pondere. Ignimbritele formeaza corpuri masive de dimensiuni variabile, cu aspect lenticular, avand baza concava si topul plan. In dealul Crapcea au fost observate unitti de curgere constnd din tufuri de val piroclastic, ignimbrite si depozite de cadere Seghedi et al, Masa principala a riolitelor din Crapcea este insa sudata, rocile avand culoare verzuie sau rosie, cu aparenta riolitica.

Ignimbritele constu dintr-o matrice de granulatia cenusii formate din vitroclaste si cristaloclaste n zircon dating de accretion crustal oceanic plutesc poncii, poncii tasate fiamme si litoclaste de dimensiuni variabile, att juvenile, cat si nevulcanice.

Caracterele acestui facies indica depunerea din curgeri gravitationale n masa, ce se deplaseaza laminar, favorizand procese de sortare granulometrica la baza curgerii. Tufurile cu stratificatie paralela sunt fie interstratificate cu depozitele epiclastice, fie localizate la partea superioara a unei curgeri piroclastice. Această interpretare este susținută de depozite care datează de la mijlocul anului Cambrian în nordul Groenlandeiunde, în câțiva zeci de kilometri, comunitățile normale de trilobit laurentian cu margine de raft artropode marine cu trei lobi distinctivi se clasifică în faune de apă adâncă, precum cele din depozitele cu rafturi superficiale din Baltica.

În mod similar, speciile de trilobite din faunele cambriene de apă adâncă de mai târziu, găsite în vestul Statelor Uniteapar și în sud-estul Chinei, în timp ce comunitățile de apă superficială din cele două regiuni au puține genuri în comun.

As large tectonic plates continued to move during the Phanerozoic Eonterranes of various sizes were displaced. Endemic Cambrian fossils, in conjunction with other geologic evidence such as physical stratigraphy, have been useful for identifying the geographic origins of some terranes, particularly those that have undergone substantial displacement.

Examples of displaced terranes include northern Scotland and west-central Argentina Precordillera with Laurentian fossils, eastern Newfoundland with fossils from Baltica, and southern Mexico Oaxaca with Gondwanan South American fossils. Another important consequence of continued plate movement has been the formation of large mountain ranges at the sites of plate collision. Pressure and heat generated during collisions since the Cambrian have foldedfaultedand metamorphosed significant volumes of Cambrian rock, especially from the outer margins and slopes of many continental shelves.

Relatively abrupt changes in sea level may have significantly influenced Cambrian environments and life. A global drop in sea level is suggested by extensive unconformities interruptions in the deposition of sedimentary rock. The time represented by such unconformities in sectors of Laurentia and Baltica bounding the Iapetus Ocean has been called the Hawke Bay event. An apparent absence of a coeval unconformity in western North America seems to be an anomaly.

Thick uninterrupted shelf deposits in this sector of Laurentia, however, may have resulted from abnormal shelf subsidence caused by the cooling of crustal rocks following a late Precambrian plate-rifting event. Among biostratigraphically important trilobites, the olenellids were exterminated near Laurentia, the holmiids went extinct at the margins of Baltica, and the redlichiids vanished from the shallow-shelf ecosystems near Gondwana. Also, diverse and abundant reef-dwelling archaeocyathans extinct group of sponges thought to have helped construct the first reefs disappeared from most low-latitude warm-water continental shelves.

The significant rise in sea level is suggested by rather abrupt and extensive displacements in sedimentary environments and zircon dating de accretion crustal oceanic during the middle of the Cambrian the Ptychagnostus gibbus zone. Lowland areas were flooded, as in parts of Baltica. In warm-water shelf sections of the world, coarse-grained, shallow-water, carbonate rocks were abruptly overlain by fine-grained, deeper-water, laminated limestone or shale.

Adaptive radiation of the pelagic agnostoid trilobites was greatly accelerated in open-oceanic environments following this event, perhaps in response to newly expanded habitats. Human Geography Study coordinated by Gr. Surd 4 ; The skiable potential of Romania P.

CoceanTerritorial diparities of the tourism supply in Romania J. Benedek ; The comparative analysis of enbvironmental education in Germany and Romania I. MacComplex rehabilitation of 4 The PhD coordinators are mentioned between brackets. Ciangă ; The geomorphological determination for the urban development of Chişinău Municipality V.

SurdeanuQuantitative methods of evaluation of the volcanic hazards in densely populated areas, with emphasis upon pyroclastic flows. Those interested in this research direction are professors Grigor P. Pop and Nicolae Ciangă, as it clearly comes out from the references.

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Taking this into account, we felt the need and at the same time the pleasure to update the issue of higher scientific research in the field of Geography at Babeş-Bolyai University by the means of this paper. Lately, due to the increase in number of PhD candidates, this situation became more and more complex and requests a certain need of restructuring.

Ciangă, N. Magistrul Şcolii geografice clujene, Edit.

Using Zircon Chemistry as a Discriminating Tool for Geodynamical Context of Magma Formation

Presa Universitară Clujeană, Cluj-Napoca. Pop, Gr. Lucrări Ştiinţifice, Seria Geografie, Oradea. Pop, P. Turnu Roşu-Călimăneşti sector is characterised by a fluvial morphology influenced by numerous conditional factors: lithology, morphometrics and morphology, gradient, sediments, all these creating a transition from the current trends that become apparent in the study of the river morphodynamics.

In order to achieve the intended purpose the following objectives were laid down: to improve the methodology of analysis and geomorphological investigation in line with current trends in the field, to highlight aspects of recent morphodynamics, as the study is based on GIS to capture the correlations between the current processes of bed scour and the effects of anthropogenic activities on inland waterway transport sector; to reveal the tendencies of development of riverbeds and slopes.

The most obvious human intervention on the river system is the construction of dams Turnu, Călimăneşti and the fitting of artificial lakes Robeşti. Olt River has witnessed important features of this type, with an evolutionary trend. Keywords: aging, the River Olt, trends, sector, natural units. The material presents a sectorial analysis of Olt River Valley by highlighting items which give it its individuality, by analysing the behaviour of the minor valley borders over time and an attempt to capture the trends on Olt Valley morphodynamics, in relation to anthropogenic influence in the area, principally through adjustments to the minor riverbed geometry, due in most situations to non-anthropogenic causes dams, works to strengthen the banks etc.

PETREA In order to highlight the evolutionary trends in Olt Valley gorge sector Turnu Roşu-Călimăneşti sectorit is necessary first to consider the circumstances that determine the conditions of entry and maintain the old river bed processes: liquid and solid discharge entries, but also the slope conditions and the nature and extent of changes in the evolution of anthropogenic-induced characteristics, determining the changes generated by accumulating in the whites of threshold effects, induced the anthropogenic accumulation through dams, gravel pits etc.

Far from being uniform, there are clearly individualized sub-sectors, each corresponding to mountain landscape divisions, as follows: Turnu Roşu Călimăneşti Sector constitutes a physical-geographical well packaged in its links with the Loviştea Basin and the mountains nearby. In the northern part of the gorge, the Boiţa-Câineni area individualizes a breakthrough of 17 km of Făgăraş and Lotru Mountains, then follows the basin down to the confluence with Lotru River, where Olt River enters the Cozia Gorge, extended over a distance of 16 km jw dating to the area of Turnu Turnu Roşu Gorge the effective entrance in the Gorge is made in the zircon dating de accretion crustal oceanic of Boiţa, which gives a varied landscape, with meadows, the piedmont hills, as Boiţa village is at the contact area of the zircon dating de accretion crustal oceanic to the mountain.

The slope of Boiţa reflects the contact between chrystalline-mesozoic and Neogene formations, evidenced by a steep scarp of m. At the entrance of the gorge to the right of Greblesti, the slopes are between tilt, which explains the presence of the embankment. The meadow is very limited in this region and in some instances the river digs its path directly through the slope, especially on the left side. The river has a skewness at Racoviţă leftwhere it widens to Copăceni, and from Călineşti to Brezoi, the course has a strong meandering to the right, by Corbu, closing towards Golotreni.

There Olt River receives one of the most important tributaries, Lotru River Văraticafollowing a significant narrowing. South of the River Greblesti to Brezoi, it has formed a wider opening allowing the location of built-up areas of localities.

This is the area of Titeşti Brezoi Corridor where the slopes range from 0 to 15 in the meadow and up to on the hillsides The Cozia Gorge between Gura Lotrului and Călimăneşti, highlights a narrowing up to the localities Câineni Cozia Călimăneşti then, with the demise of the hillsides, one notices the presence of massive escarpments whose degree of inclination surpasses This is the range with the most active slope processes, generally, due to the gravitational gradient of the slope of the landscape.

Descending towards Cozia and Căciulata, Olt River receives Căciulata tributary, changing over to the left, and forming a broad bend.

Prin a. In cazul piroclastitelor, min. Se aseamana cu unele roci terestre; reprezinta cca. Rocile a.

One notices the presence of an improved island Ostrov Convent. At the gorge exit CălimăneştiOlt River Valley widens considerably. PETREA Of the changes that occur as a result of the accumulation and fluvial erosion which meet and study within the framework of sector-level changes of islands and the number of meanders, changes of the original course of the river and the emergence of abandoned meanders taking birth due to rectification of the channel, both naturally and artificiallythe main question being posed by the migration of alluvial thresholds.

As regarding modifications to the forms of accumulation islandsfollowing their evolution one notices a decrease in their number as a result of natural evolution, but mainly due to anthropogenic causes.

In the s there was a total of 14 islands in the studied sector; at present their number has reduced to 6. In the sector between Turnu Roşu and Cozia, the process of meandering is more underrepresented Olt River through a process of correction because of reservoirs and dams.

An important element in the process of modelling by fluvial erosion is given by the geology of the substrate and the kind of dynamic characteristics of erosion in the meantime, in gorges their structure is more rough and the materials in the bed of the river are also littered with boulders, reducing transport capacity and a river-bed of aggradation. Thus, a crest conditioning is being carried out in such a threshold Fig.

Yo dating app excavation in the Olt River. Human actions over Olt River flows consists of attenuation by building collections as those from Turnu Severin, Câineni, Robesti, Cornetu, Gura Lotrului or settlement and impoundments, Călimăneşti-Căciulata, borders, by the presence or possible collections associated with dams due to mining in local channels, or of the type of gravel pits.

We note the existence of two types of construction of water projects that have different implications in the fluvial dynamics of cross-sector with strikethrough, they interrupt the longitudinal connectivity in rivers resulting effects on the hydrological regime and the sedimentary transport; and strikethrough that interrupt the connectivity of the longitudinal sides of the water bodies with meadows as important fields known as important self-control spaces and at the same time stresses the increasing concentration in the currents, erosion, pushing zircon dating de accretion crustal oceanic to the cross-sectional areas of strikethrough, however resulting in deterioration of general condition of the River.

Încărcat de

In most cases the influence of the dam on the flow stream would result in additional volume of water and sediment in suspension, thus changing the liquid and solid natural outflow. Adjustments to the shape of the analysed sector as a whole or to the level of detail are responses to the rhythms and sense of energy and mass leak inside the morphological system. The longitudinal profile of Olt Valley highlights areas of narrowing gorges and areas of morfodinamics, the last stretch being materialized in the territory by a depression chute the depresional passage Lotru Brezoi Loviştea.

This scheme of narrowings and stretches, is the result of the evolution and dynamics of the Valley, through the natural processes of evolution over overlapping the intense antropical processes which they undergo this sector at present. The most obvious human intervention on the river systems are the constructions of dams Turnu, Călimăneşti and fitting of artificial lakes Robeşti. Olt River has experienced important developments of this kind, with an evolutionary trend.

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Accumulation lakes, built with multiple purposes such as drinking water supply and industrial or energy purposes of protection against floods, causing as a hydromorphological pressure the interruption of the continuity of the flow and settlements of water flows. The main collections of accumulations in the study area can be found on Olt River, and part of the hydrographic network of its tributaries.

Pop, In addition to the changes in the characteristics and course of the river, induced by the presence of accumulation, the river has gone through significant changes. Among them were the anthropogenic river bed aggradation processes, such as in the case of CHE Călimăneşti, construction of which they were required to work which consisted of approximately 6 m with lifting of the Calimanesti Hermitage island, in the case of the dam at Turnu, for which they were required to work the railroad segment with 20 m and DN7the highway that crosses the lupta fanilor 4 oktober at Cozia, or lifting and strengthening the remains of a roman Arutela, located in the bed of Olt River.

As a whole, the entire river system in the sector of interest, is influenced by fluctuations of flow and fluctuations of stream bed, which rapidly counterbalancces between accumulation and erosion, in search of a state of dynamical equilibrium.

We believe that in these circumstances, the most important factor in defining the trends of the recent evolution of anthropogenic nature, and is mainly linked to the use of collections of water projects and the exploitation of material from the bed of the river.

Grigore, M. Ştiinţifică şi Enciclopedică, Bucureşti. Leopold, L. Freeman and Company, San Francisco. Orghidan, N. Academiei Republicii Socialiste România, Bucureşti. Petrea, D. Posea, G. Ştiinţifică, Bucureşti. Rădoane, Maria, extras din articolul cu titlul: Cercetări de geomorfologie zircon dating de accretion crustal oceanic pentru cunoaşterea modificărilor la nivelul albiilor de râu. Tufescu, V. The study presents a petrographic and geomorphologic research in which we identified important aspects of the geological formation and described geomorphological features of Kenai and Chugach Mountains in the Whittier Area, Alaska State.

The general objectives are a check-up and presentation of the nature of rocks and typical landforms of glacial models. The field research includes observations on landscapes, the peculiar forms and samples of rocks from various locations, in order to see the local or allochthonous character, knowing that the glaciers can transport materials for long distances.

Every rock sample was cut and studied in section at the microscope. The glacial landforms and the types of glaciers existing in Whittier Area were analysed in the field.

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Keywords: geology, geomorphology, rocks, glaciers, Kenai, Chugach, Whittier, Alaska. The geographical territory presents obvious limits, because Whittier is at the head of the Passage Canal of Prince William Sound. Both sectors of mountain chains record heights over meters and are covered by glaciers and icefields, and some glaciers slip into the ocean. The petrographical objective of research was a study of the types of rocks from Whittier Area and of the variety of landforms which have developed on the existing geology, considering that the morphological features are changed by glaciers.

Also, the petrographic observations illustrate the geologic formations from the Alpine orogen, Alaska. The observations in the field have a geomorphological nature in the proximity of glaciers action zone. The methods used in this research are at macroscale in field where sample rocks were taken and at microscale the manufacture of the thin sections for the microscope study in polarized light of the mineral characteristics.

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The localization of study area on Alaska physical map. Geological map of Alaska. Localization of petrographic interesting points. From a geological point of view, the area is situated on the tectonic compression active line, where the Pacific plate is diving under the American continental margin. The land surfaces in Alaska are continually compressed and folded, which pushes up McKinley Mountain, as well as the rest of the mountains in the Alaska Range. These processes influence the geology of the area and result into various types of associations in the same place: Terranes accreted, Arctic and insular terranes, Intermontane terranes, Oceanic terranes, Ancestral North America fig.

The samples of rock examinated were taken from the front of the Whittier Glacier, the front of the Learnard Glaciers and Shakespeare Shoulder m fig. The height where we made the research was between m and m along the ice-blocks of the glacier fig.

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The majority of the rocks existing in the proximity of the Whittier Glacier are slates, sandstones and graywackes of Cretaceous age. The sedimentary rocks and terrestrial clastic brought by glacial torrents belong to the Pliocene.