Abstract. The investigations focused on two profiles from the Black Sea, placed in front of the P... more Abstract. The investigations focused on two profiles from the Black Sea, placed in front of the Portiţa Mouth and in the south-eastern part of the Sahalin Island. Up to 40 m water depth, the samples from the Portiţa profile contain only reworked Mesozoic and Cenozoic calcareous nannoplankton taxa. In the same profile, the bloom of the calcareous nannoplankton species Emiliania huxleyi, together with abundant benthic foraminiferal taxa, were recorded in the first 11 cm of sediments, at below 40 m water depth. All the samples collected in the SE of Sahalin Island contain only Mesozoic and Cenozoic reworked calcareous nannoplankton taxa; no marine assemblages in situ were remarked.
Page 1. ACTA PALAEONTOLOGICA ROMANIAE V. 5 (2005), P. 423-439 PALEOGENE LITHO-AND BIOSTRATIGRAPHY... more Page 1. ACTA PALAEONTOLOGICA ROMANIAE V. 5 (2005), P. 423-439 PALEOGENE LITHO-AND BIOSTRATIGRAPHY OF THE NE GETIC DEPRESSION (ROMANIA) Relu - Dumitru ROBAN1 and Mihaela Carmen MELINTE2 ...
Sommaire Quatre etudes des nannofossiles calcaires de la succession de Tercis les Bains ont ete r... more Sommaire Quatre etudes des nannofossiles calcaires de la succession de Tercis les Bains ont ete realisees independamment dans le but de caracteriser la succession du Campanien superieur-Masstrichtien inferieur. La comparaison des resultats realisee dans ce chapitre permet de definir des bio-horizons ainsi que leur reproductibilite pratique. La comparaison avec d'autres sections autorise leur interpretation en termes d'evolution biologique et suggere des criteres de correlation. La preservation des nannofossiles calcaires varie de moyenne a mauvaise. Elle est cependant suffisamment bonne pour identifier des taxons en depit des surcroissances minerales. La diversite de la nannoflore est assez grande partout dans la succession au-dessus des niveaux basaux. Au total, plus de 150 taxons ont ete cites. Des bio-horizons d'apparition locale (AL) ou de disparition locale (DL) ont ete definis. Une dizaine de signaux sont aisement identifies. L'AL de C. aculeus est anterieure a la limite entre les unites Hontarede et d'Avezac, les AL de A. parcus constrictus et A. cymbiformis aussi. Les AL et DL de Q. trifidum constituent les deux signaux majeurs bien reproduits par les expertises aux cotes 52,5±2,4 et 134,2±2,7. De meme pour la DL des Nannoconus qui est localisee au milieu de l'affleurement principal a la cote 90,5±1,5. L' AL (cote 7,4±6,9) et la DL (129,1±2,4?) de Q. gothicum ne sont pas tres precisement reproductibles. Enfin, la DL de A. parcus constrictus a ete situee presque au sommet de l'affleurement principal, dans l'Unite Les Vignes (cote 160,1±7,4). Les DL de T. orionatus et R. levis sont toutes deux audessus de la cote 174, dernier niveau considere dans ces expertises. D'autres faits sont presents mais plus difficilement localises: ils sont soit reperes a des niveaux differents soit mis en evidence dans une ou deux etudes seulement. Les causes de divergences sont diverses et peuvent etre attribuees a divers facteurs illustres dans cette etude cooperative: 1) le procede de preparation des frottis et le temps passe a l'observation; ceux-ci necessiteraient une uniformisation; la position de la DL de E. eximius est concernee par ce facteur; 2) les problemes taxonomiques; c'est sans doute le cas pour les taxons R. magnus et Q. sissinghi qui n'ont ete cites que dans un seul rapport chacun; 3) la difficulte d'identification de certains taxons mal preserves ou qui peuvent etre confondus a cause des surcroissances cristallines; un bon exemple est donne par la diversite de localisation de la DL de R. anthophorus par rapport a l'AL de R. levis , 4) le probleme de l'interpretation des taxons isoles de leur zone de repartition commune: remaniement ou pas; c'est le cas de quelques specimens de Nannoconus observes dans l'Unite Les Vignes et des derniers E. eximius , pres de la limite d'Etage, dont on ne peut savoir assurement s'ils sont en place ou remanies; enfin 5) les differences naturelles d'assemblage d'un prelevement a l'autre. Les repartitions retenues dans ce chapitre ont tenu compte des facteurs d'abondance cites par les experts et du temps qu'ils ont consacre a l'etude. Pres de 15 signaux significatifs ont ete reperes en tout pour une succession couvrant environ 5 Ma. A partir de ces signaux, on peut proposer 5 intervalles dans lesquels la nannoflore est caracterisee par des criteres de contemporaneite ou d'exclusion de formes caracteristiques; les coupures sont aux cotes 52,5, 90,5, 134,2 et 160,1. Grâce a ces cinq intervalles caracteristiques successifs associes a des criteres sedimentologiques (glauconie, restes siliceux cf. chap. B1a) on peut esperer identifier la provenance de morceaux de roche, y compris des fossiles de collections anciennes, avec une precision de l'ordre de 5 a 15 m. Par ailleurs, certains des bio-horizons cites ci-dessus sont communs avec ceux utilises dans des modeles de Roth est applicable et ses biozones NC 19, NC 20 et NC 21 peuvent etre reconnues. Le modele de Sissingh est plus difficile a appliquer mais ses biozones CC 20, CC 21, CC 22, CC 23A et CC 23B peuvent etre localisees approximativement. Aux plans environmental et sedimentologique, les resultats disponible indiquent und changement floristique entre les cotes 84 et 89. Il n'y a pas de lacune de depot decelable a ce niveau et ce changement est lie, semble t-il, a une ouverture plus grande sur la masse oceanique. Par contre, on n'observe pas de changement floristique sensible autour de la limite d'Etage ni au niveau du banc glauconieux et phosphate de la cote 67. Ces observations militent pour un depot relativement continu de l'ensemble de la succession. La suite des bio-horizons reperes dans la succession de Tercis est conforme a celle generalement observee dans d'autres series sedimentaires. Par ailleurs, la biozone NC 20 constituee par l'intervalle d'existence de Q. trifidum convrirait une duree estimee a 3,5 Ma d'apres le taux moyen de depot adopte a Tercis et la regularite de la vitesse de depot. Cette duree est tres…
After some deontological considerations, we confirm that evidence of Mediterranean reflooding by ... more After some deontological considerations, we confirm that evidence of Mediterranean reflooding by Atlantic waters occurs significantly below the formally defined base of the Zanclean Stage at 5.332 Ma, as shown by the lowest occurrence of the calcareous ...
Abstract. The objective of the present study case is to demonstrate that the geographical landsca... more Abstract. The objective of the present study case is to demonstrate that the geographical landscape affected by the uraniferous mining activities can be recovered in the benefit of the touristic activity, of the biodiversity conservation, as well as historical and cultural patrimony preservation. In order to reorganize the post-mining geographical space by enhancing the balance between economic activities and environmental protection a solution with positive long-term effects is suggested and discussed in the paper.
We present new sedimentological, petrographical, palaeontological and detrital zircon U–Pb data o... more We present new sedimentological, petrographical, palaeontological and detrital zircon U–Pb data on late Oligocene–early Miocene sedimentary rocks of the thin-skinned thrust belt of East Carpathians. These data were acquired to reconstruct the sedimentary routing system for two compositionally different turbidite fans made of the regionally extensive Kliwa and Fusaru formations. On the eastern margin of the Moldavides foreland basin, large low-gradient river systems draining the East European Platform provided well-sorted quartz-rich sand forming deltas on wide shallow shelves and thick Kliwa submarine fans. Due to the westward subduction of a thinned continental plate, the western basin margin was characterized by short, steep-gradient routing systems where sediment transport to deep water was mainly through hyperpycnal flows. The Getic and Bucovinian nappes of the East Carpathians and the exhumed Cretaceous–Early Palaeogene orogenic wedge fed Fusaru fans with poorly sorted lithic sand. The Fusaru fans trend northwards in the foredeep basin having an elongate depocentre, interfingering and then overlapping on the distal part of the Kliwa depositional system due to the eastward advance of the Carpathian fold-and-thrust belt. A smaller sediment input is supplied by southern continental areas (i.e. Moesian Platform, North Dobrogea and potentially the Balkans). In general, the sandstone interfingering between distinct basin floor fan systems is less well documented because the facies would be similar and there are not many systems that have a distinct sediment provenance like Kliwa and Fusaru systems. This case study improves the understanding of regional palaeogeography and sedimentary routing systems and provides observations relevant here or elsewhere on the interfingering turbidite fan systems.
Stratigraphy, Composition, Origins, and Paleoceanographic and Paleoclimatic Significance, 2009
ABSTRACT The uppermost Cretaceous marine red beds from the Romanian Carpathian bend area were inv... more ABSTRACT The uppermost Cretaceous marine red beds from the Romanian Carpathian bend area were investigated in detail from the lithostratigraphic and biostratigraphic points of view. Geochemical and mineralogical investigations were performed along the same profile. The investigated sequence spans the Upper Campanian and the whole Maastrichtian stages, including the K–T boundary, as evidenced by the nannofloral mass extinction and the well known carbon isotope excursion. Both qualitative and semiquantitative calcareous nannofossil studies were conducted. The semiquantitative investigations focused on six taxonomic groups, such as Watznaueria barnesae, Micula spp., Boreal nannofossils, Tethyan nannofossils, Braarudosphaera bigelowii, and the calcareous dinoflagellate genus Thoracosphaera. The new data indicate constant δ 13 C values in the Upper Campanian and Lower Maastrichtian red marls of the Gura Beliei Formation. In the Upper Maastrichtian deposits of the Ialomica section, lithological and mineralogical changes, together with several negative δ 13 C and δ 18 O excursions, suggest instability of the ecosystems, fluctuating sea level, and/or detrital input as well as climatic changes during the Late Maastrichtian interval. The age and the lithology of the Gura Beliei red beds are similar to other red beds deposited in the Tethys Realm (i.e., the Nierental Formation of Austrian Northern Calcareous Alps, the Púchov Marl of the Slovakian and Polish Western Carpathians, the Vojvodina region of Serbia, and the Scaglia Rossa of Apennines).
Main taxonomical and biostratigraphical features of the calcareous nannoplankton, algae widesprea... more Main taxonomical and biostratigraphical features of the calcareous nannoplankton, algae widespread in all the marine environments are discussed. The biostratigraphy and the distribution of this group of organisms for the last 225 Ma are also presented. The calcareous nannoplankton, as most of the planktonic organisms, reflects with high fidelity environmental changes, such as fluctuations of light, salinity, temperature, sea-level changes, ocean productivity, nutrients and water pollution. The key role of the calcareous nannoplankton in reconstructing palaeoecological changes, in identifying global and regional environmental modifications and in advancing climatic predictions is argued.
The Organy�a Basin, southecentral Spanish Pyrenees, developed as a marginal depocenter during a r... more The Organy�a Basin, southecentral Spanish Pyrenees, developed as a marginal depocenter during a rapid extensional phase of anticlockwise rotation of the Iberian plate. As a result of increased subsidence, an important change in sedimentation occurred from the late Barremian to the Aptian leading to unusually high sediment accumulation rates. Approximately 1000 m of hemipelagic marls and limestones accumulated during this time interval. Here we studied the basal 85 m of the hemipelagic facies of the El Pui section, Organy�a Basin, that are characterized by alternating 15 cm e ~3 m thick beds of limestone and marls. Geochemical analyses indicate high total inorganic carbon (TIC) values (average 70%) suggesting enhanced CaCO3 production and deposition. SEM analyses of the samples indicate high abundance of calcareous nannofossils, which together with the absence of shallow water taxa characteristic of the Urgonian Carbonate platform of Organy�a, and the lack of sedimentary facies attri...
Abstract: Several sites from the NW Black Sea, namely, the Romanian Black Sea shelf, situated at ... more Abstract: Several sites from the NW Black Sea, namely, the Romanian Black Sea shelf, situated at water depths ranging from 17 m to 80 m, have been investigated.<br> The superficial sediments, i.e., the water/sediment interface, were analyzed for their calcareous nannoplankton content. Both quantitative and<br> qualitative nannofloral analyses have been performed. The nannofloral assemblages that are in situ contain only Emiliania huxleyi and Braarudosphaera<br> bigelowii. Offshore, in front of the Danube mouth, only resedimented calcareous nannofossils from older Mesozoic-Tertiary deposits are present. Concerning<br> the nannofloras in situ, the maximum bloom of Emiliania huxleyi in the studied area is placed in the region where the influx in sediments and waters<br> rich in nutrients is significant, due to the input of both the Danube and Dniepr rivers, at a distance exceeding 30-40 km from the coastline. Apart from the<br> coccolithophore algae,...
Abstract. Tuzla Lake emerged in the 70's as an extension of Techirghiol Lake. The forming of ... more Abstract. Tuzla Lake emerged in the 70's as an extension of Techirghiol Lake. The forming of the lake occurred due to human factors (intensive irrigations) and was favoured by natural factors (years of intense pluvial regime). The periodical increase of the Tuzla Lake level produced flooding in the area; the most recent ones (September 2005) significantly affected the buildings and the land around Tuzla Town. In order to evaluate the geo-ecological state of Tuzla Lake, including the impact from the last flooding events on the morphology of the lacustrine basin, the following investigations were performed: bathymetry measurements, sedimentological evaluations, and determination of the physico-chemical, chemical and microbiological parameters of the water. These investigations were performed during 2005 and 2006, and they consisted of the periodical sampling of the water and sediments as well as of bathymetry measurements sensu stricto before and after the 2005 flooding events. Th...
The Apuseni Mountains were formed during Late Cretaceous convergence between the Tisia and the Da... more The Apuseni Mountains were formed during Late Cretaceous convergence between the Tisia and the Dacia microplates as part of the Alpine orogen. The mountain range comprises a sedimentary succession similar to the Gosau Group of the Eastern Alps. This work focuses on the sedimentological and geodynamic evolution of the Gosau basin of the Apuseni Mts. and attempts a direct comparison to the relatively well studied Gosau Group deposits of the Eastern Alps. By analyzing the Upper Cretaceous Gosau sediments and the surrounding geological units, we were able to add critical evidence for reconstructing the Late Mesozoic to Paleogene geodynamic evolution of the Apuseni Mountains. Nannoplankton investigations show that Gosau sedimentation started diachronously after Late Turonian times. The burial history indicates low subsidence rates during deposition of the terrestrial and shallow marine Lower Gosau Subgroup and increased subsidence rates during the period of deep marine Upper Gosau Subgro...
Abstract. The investigations focused on two profiles from the Black Sea, placed in front of the P... more Abstract. The investigations focused on two profiles from the Black Sea, placed in front of the Portiţa Mouth and in the south-eastern part of the Sahalin Island. Up to 40 m water depth, the samples from the Portiţa profile contain only reworked Mesozoic and Cenozoic calcareous nannoplankton taxa. In the same profile, the bloom of the calcareous nannoplankton species Emiliania huxleyi, together with abundant benthic foraminiferal taxa, were recorded in the first 11 cm of sediments, at below 40 m water depth. All the samples collected in the SE of Sahalin Island contain only Mesozoic and Cenozoic reworked calcareous nannoplankton taxa; no marine assemblages in situ were remarked.
Page 1. ACTA PALAEONTOLOGICA ROMANIAE V. 5 (2005), P. 423-439 PALEOGENE LITHO-AND BIOSTRATIGRAPHY... more Page 1. ACTA PALAEONTOLOGICA ROMANIAE V. 5 (2005), P. 423-439 PALEOGENE LITHO-AND BIOSTRATIGRAPHY OF THE NE GETIC DEPRESSION (ROMANIA) Relu - Dumitru ROBAN1 and Mihaela Carmen MELINTE2 ...
Sommaire Quatre etudes des nannofossiles calcaires de la succession de Tercis les Bains ont ete r... more Sommaire Quatre etudes des nannofossiles calcaires de la succession de Tercis les Bains ont ete realisees independamment dans le but de caracteriser la succession du Campanien superieur-Masstrichtien inferieur. La comparaison des resultats realisee dans ce chapitre permet de definir des bio-horizons ainsi que leur reproductibilite pratique. La comparaison avec d'autres sections autorise leur interpretation en termes d'evolution biologique et suggere des criteres de correlation. La preservation des nannofossiles calcaires varie de moyenne a mauvaise. Elle est cependant suffisamment bonne pour identifier des taxons en depit des surcroissances minerales. La diversite de la nannoflore est assez grande partout dans la succession au-dessus des niveaux basaux. Au total, plus de 150 taxons ont ete cites. Des bio-horizons d'apparition locale (AL) ou de disparition locale (DL) ont ete definis. Une dizaine de signaux sont aisement identifies. L'AL de C. aculeus est anterieure a la limite entre les unites Hontarede et d'Avezac, les AL de A. parcus constrictus et A. cymbiformis aussi. Les AL et DL de Q. trifidum constituent les deux signaux majeurs bien reproduits par les expertises aux cotes 52,5±2,4 et 134,2±2,7. De meme pour la DL des Nannoconus qui est localisee au milieu de l'affleurement principal a la cote 90,5±1,5. L' AL (cote 7,4±6,9) et la DL (129,1±2,4?) de Q. gothicum ne sont pas tres precisement reproductibles. Enfin, la DL de A. parcus constrictus a ete situee presque au sommet de l'affleurement principal, dans l'Unite Les Vignes (cote 160,1±7,4). Les DL de T. orionatus et R. levis sont toutes deux audessus de la cote 174, dernier niveau considere dans ces expertises. D'autres faits sont presents mais plus difficilement localises: ils sont soit reperes a des niveaux differents soit mis en evidence dans une ou deux etudes seulement. Les causes de divergences sont diverses et peuvent etre attribuees a divers facteurs illustres dans cette etude cooperative: 1) le procede de preparation des frottis et le temps passe a l'observation; ceux-ci necessiteraient une uniformisation; la position de la DL de E. eximius est concernee par ce facteur; 2) les problemes taxonomiques; c'est sans doute le cas pour les taxons R. magnus et Q. sissinghi qui n'ont ete cites que dans un seul rapport chacun; 3) la difficulte d'identification de certains taxons mal preserves ou qui peuvent etre confondus a cause des surcroissances cristallines; un bon exemple est donne par la diversite de localisation de la DL de R. anthophorus par rapport a l'AL de R. levis , 4) le probleme de l'interpretation des taxons isoles de leur zone de repartition commune: remaniement ou pas; c'est le cas de quelques specimens de Nannoconus observes dans l'Unite Les Vignes et des derniers E. eximius , pres de la limite d'Etage, dont on ne peut savoir assurement s'ils sont en place ou remanies; enfin 5) les differences naturelles d'assemblage d'un prelevement a l'autre. Les repartitions retenues dans ce chapitre ont tenu compte des facteurs d'abondance cites par les experts et du temps qu'ils ont consacre a l'etude. Pres de 15 signaux significatifs ont ete reperes en tout pour une succession couvrant environ 5 Ma. A partir de ces signaux, on peut proposer 5 intervalles dans lesquels la nannoflore est caracterisee par des criteres de contemporaneite ou d'exclusion de formes caracteristiques; les coupures sont aux cotes 52,5, 90,5, 134,2 et 160,1. Grâce a ces cinq intervalles caracteristiques successifs associes a des criteres sedimentologiques (glauconie, restes siliceux cf. chap. B1a) on peut esperer identifier la provenance de morceaux de roche, y compris des fossiles de collections anciennes, avec une precision de l'ordre de 5 a 15 m. Par ailleurs, certains des bio-horizons cites ci-dessus sont communs avec ceux utilises dans des modeles de Roth est applicable et ses biozones NC 19, NC 20 et NC 21 peuvent etre reconnues. Le modele de Sissingh est plus difficile a appliquer mais ses biozones CC 20, CC 21, CC 22, CC 23A et CC 23B peuvent etre localisees approximativement. Aux plans environmental et sedimentologique, les resultats disponible indiquent und changement floristique entre les cotes 84 et 89. Il n'y a pas de lacune de depot decelable a ce niveau et ce changement est lie, semble t-il, a une ouverture plus grande sur la masse oceanique. Par contre, on n'observe pas de changement floristique sensible autour de la limite d'Etage ni au niveau du banc glauconieux et phosphate de la cote 67. Ces observations militent pour un depot relativement continu de l'ensemble de la succession. La suite des bio-horizons reperes dans la succession de Tercis est conforme a celle generalement observee dans d'autres series sedimentaires. Par ailleurs, la biozone NC 20 constituee par l'intervalle d'existence de Q. trifidum convrirait une duree estimee a 3,5 Ma d'apres le taux moyen de depot adopte a Tercis et la regularite de la vitesse de depot. Cette duree est tres…
After some deontological considerations, we confirm that evidence of Mediterranean reflooding by ... more After some deontological considerations, we confirm that evidence of Mediterranean reflooding by Atlantic waters occurs significantly below the formally defined base of the Zanclean Stage at 5.332 Ma, as shown by the lowest occurrence of the calcareous ...
Abstract. The objective of the present study case is to demonstrate that the geographical landsca... more Abstract. The objective of the present study case is to demonstrate that the geographical landscape affected by the uraniferous mining activities can be recovered in the benefit of the touristic activity, of the biodiversity conservation, as well as historical and cultural patrimony preservation. In order to reorganize the post-mining geographical space by enhancing the balance between economic activities and environmental protection a solution with positive long-term effects is suggested and discussed in the paper.
We present new sedimentological, petrographical, palaeontological and detrital zircon U–Pb data o... more We present new sedimentological, petrographical, palaeontological and detrital zircon U–Pb data on late Oligocene–early Miocene sedimentary rocks of the thin-skinned thrust belt of East Carpathians. These data were acquired to reconstruct the sedimentary routing system for two compositionally different turbidite fans made of the regionally extensive Kliwa and Fusaru formations. On the eastern margin of the Moldavides foreland basin, large low-gradient river systems draining the East European Platform provided well-sorted quartz-rich sand forming deltas on wide shallow shelves and thick Kliwa submarine fans. Due to the westward subduction of a thinned continental plate, the western basin margin was characterized by short, steep-gradient routing systems where sediment transport to deep water was mainly through hyperpycnal flows. The Getic and Bucovinian nappes of the East Carpathians and the exhumed Cretaceous–Early Palaeogene orogenic wedge fed Fusaru fans with poorly sorted lithic sand. The Fusaru fans trend northwards in the foredeep basin having an elongate depocentre, interfingering and then overlapping on the distal part of the Kliwa depositional system due to the eastward advance of the Carpathian fold-and-thrust belt. A smaller sediment input is supplied by southern continental areas (i.e. Moesian Platform, North Dobrogea and potentially the Balkans). In general, the sandstone interfingering between distinct basin floor fan systems is less well documented because the facies would be similar and there are not many systems that have a distinct sediment provenance like Kliwa and Fusaru systems. This case study improves the understanding of regional palaeogeography and sedimentary routing systems and provides observations relevant here or elsewhere on the interfingering turbidite fan systems.
Stratigraphy, Composition, Origins, and Paleoceanographic and Paleoclimatic Significance, 2009
ABSTRACT The uppermost Cretaceous marine red beds from the Romanian Carpathian bend area were inv... more ABSTRACT The uppermost Cretaceous marine red beds from the Romanian Carpathian bend area were investigated in detail from the lithostratigraphic and biostratigraphic points of view. Geochemical and mineralogical investigations were performed along the same profile. The investigated sequence spans the Upper Campanian and the whole Maastrichtian stages, including the K–T boundary, as evidenced by the nannofloral mass extinction and the well known carbon isotope excursion. Both qualitative and semiquantitative calcareous nannofossil studies were conducted. The semiquantitative investigations focused on six taxonomic groups, such as Watznaueria barnesae, Micula spp., Boreal nannofossils, Tethyan nannofossils, Braarudosphaera bigelowii, and the calcareous dinoflagellate genus Thoracosphaera. The new data indicate constant δ 13 C values in the Upper Campanian and Lower Maastrichtian red marls of the Gura Beliei Formation. In the Upper Maastrichtian deposits of the Ialomica section, lithological and mineralogical changes, together with several negative δ 13 C and δ 18 O excursions, suggest instability of the ecosystems, fluctuating sea level, and/or detrital input as well as climatic changes during the Late Maastrichtian interval. The age and the lithology of the Gura Beliei red beds are similar to other red beds deposited in the Tethys Realm (i.e., the Nierental Formation of Austrian Northern Calcareous Alps, the Púchov Marl of the Slovakian and Polish Western Carpathians, the Vojvodina region of Serbia, and the Scaglia Rossa of Apennines).
Main taxonomical and biostratigraphical features of the calcareous nannoplankton, algae widesprea... more Main taxonomical and biostratigraphical features of the calcareous nannoplankton, algae widespread in all the marine environments are discussed. The biostratigraphy and the distribution of this group of organisms for the last 225 Ma are also presented. The calcareous nannoplankton, as most of the planktonic organisms, reflects with high fidelity environmental changes, such as fluctuations of light, salinity, temperature, sea-level changes, ocean productivity, nutrients and water pollution. The key role of the calcareous nannoplankton in reconstructing palaeoecological changes, in identifying global and regional environmental modifications and in advancing climatic predictions is argued.
The Organy�a Basin, southecentral Spanish Pyrenees, developed as a marginal depocenter during a r... more The Organy�a Basin, southecentral Spanish Pyrenees, developed as a marginal depocenter during a rapid extensional phase of anticlockwise rotation of the Iberian plate. As a result of increased subsidence, an important change in sedimentation occurred from the late Barremian to the Aptian leading to unusually high sediment accumulation rates. Approximately 1000 m of hemipelagic marls and limestones accumulated during this time interval. Here we studied the basal 85 m of the hemipelagic facies of the El Pui section, Organy�a Basin, that are characterized by alternating 15 cm e ~3 m thick beds of limestone and marls. Geochemical analyses indicate high total inorganic carbon (TIC) values (average 70%) suggesting enhanced CaCO3 production and deposition. SEM analyses of the samples indicate high abundance of calcareous nannofossils, which together with the absence of shallow water taxa characteristic of the Urgonian Carbonate platform of Organy�a, and the lack of sedimentary facies attri...
Abstract: Several sites from the NW Black Sea, namely, the Romanian Black Sea shelf, situated at ... more Abstract: Several sites from the NW Black Sea, namely, the Romanian Black Sea shelf, situated at water depths ranging from 17 m to 80 m, have been investigated.<br> The superficial sediments, i.e., the water/sediment interface, were analyzed for their calcareous nannoplankton content. Both quantitative and<br> qualitative nannofloral analyses have been performed. The nannofloral assemblages that are in situ contain only Emiliania huxleyi and Braarudosphaera<br> bigelowii. Offshore, in front of the Danube mouth, only resedimented calcareous nannofossils from older Mesozoic-Tertiary deposits are present. Concerning<br> the nannofloras in situ, the maximum bloom of Emiliania huxleyi in the studied area is placed in the region where the influx in sediments and waters<br> rich in nutrients is significant, due to the input of both the Danube and Dniepr rivers, at a distance exceeding 30-40 km from the coastline. Apart from the<br> coccolithophore algae,...
Abstract. Tuzla Lake emerged in the 70's as an extension of Techirghiol Lake. The forming of ... more Abstract. Tuzla Lake emerged in the 70's as an extension of Techirghiol Lake. The forming of the lake occurred due to human factors (intensive irrigations) and was favoured by natural factors (years of intense pluvial regime). The periodical increase of the Tuzla Lake level produced flooding in the area; the most recent ones (September 2005) significantly affected the buildings and the land around Tuzla Town. In order to evaluate the geo-ecological state of Tuzla Lake, including the impact from the last flooding events on the morphology of the lacustrine basin, the following investigations were performed: bathymetry measurements, sedimentological evaluations, and determination of the physico-chemical, chemical and microbiological parameters of the water. These investigations were performed during 2005 and 2006, and they consisted of the periodical sampling of the water and sediments as well as of bathymetry measurements sensu stricto before and after the 2005 flooding events. Th...
The Apuseni Mountains were formed during Late Cretaceous convergence between the Tisia and the Da... more The Apuseni Mountains were formed during Late Cretaceous convergence between the Tisia and the Dacia microplates as part of the Alpine orogen. The mountain range comprises a sedimentary succession similar to the Gosau Group of the Eastern Alps. This work focuses on the sedimentological and geodynamic evolution of the Gosau basin of the Apuseni Mts. and attempts a direct comparison to the relatively well studied Gosau Group deposits of the Eastern Alps. By analyzing the Upper Cretaceous Gosau sediments and the surrounding geological units, we were able to add critical evidence for reconstructing the Late Mesozoic to Paleogene geodynamic evolution of the Apuseni Mountains. Nannoplankton investigations show that Gosau sedimentation started diachronously after Late Turonian times. The burial history indicates low subsidence rates during deposition of the terrestrial and shallow marine Lower Gosau Subgroup and increased subsidence rates during the period of deep marine Upper Gosau Subgro...
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