MARIUS STOICA

The critical analysis of the Gura Văii-Turnu Severin-Izvoru Bârzii Gilbert-type deltas concentrated on the deltaic architecture and the age of the deltaic deposits , referring especially to the conglomeratic sediments considered the proximal foreset unit of the Gilbert-type fan deltas. It reveals the lack of evidences necessary to demonstrate the existence of the three units (foreset, bottomset and topset beds) which define a Gilbert-type delta. Although there are convincing data for its tectonic origin, the homoclinal structure of these deltaic deposits was considered, with no argumentation, as a primary structure generated through the deltaic progradation. The age of the rudaceous deposits in the area Gura Văii-Turnu Severin-Izvoru Bârzii, representing the core of the two outlined Gilbert deltas, was considered Zanclean (Bosphorian) by Clauzon et al. (2005) and Suc et al. (2011), rejecting the Badenian-Sarmatian (s.l.) age formerly attributed (Marinescu, 1978 and the references he...

The Paratethys was a large network of inland seas that once extended from central Europe to inner Asia, encompassing major sedimentary basins such as the Pannonian, Dacian and Euxinian (Black Sea) basin. Since the Miocene the Paratethys Sea retreated eastward to the present-day Black Sea due to the uplift of the Carpathians and other mountain ranges. One very important step in this retreat was the isolation of the Pannonian basin (Central Paratethys) from the remainder of the system. The discussion on when the isolation exactly occurred and what triggered it is still ongoing. The isolation had profound implications for the sediment transfer between the Paratethys basins; erosional products could no longer be transferred across the Carpathians, from the Pannonian and Transylvanian to the Dacian basin. This led to increased sedimentation in the Pannonian basin and, ultimately, its complete fill. In this study we use magnetostratigraphy to constrain the age of the Miocene isolation of ...

<p>The largest megalake in the record formed in Eurasia during the late Miocene, when the epicontinental Paratethys Sea became tectonically-trapped and disconnected from the global ocean. The Paratethys megalake was characterized by several episodes of hydrological instability and partial desiccation, but the chronology, magnitude and impacts of these paleoenvironmental crises are poorly known. The Panagia section on the Taman Peninsula of Russia is the only place known to host a continuous sedimentary record of the late Miocene hydrological crises of Paratethys. Paleomagnetic measurements allow the development of a polarity pattern that can be used to date the regression events. The Panagia polarity pattern consists of 17 polarity intervals, 9 of normal polarity and 8 of reversed polarity, plus 4 additional short-term polarity fluctuations, that are inferred to correspond to the 11-7.5 Ma interval. We identified four major regressions that correlate with aridification events, vegetation changes and faunal turnovers in large parts of Europe. Our paleogeographic reconstructions reveal that Paratethys was profoundly transformed during the regression episodes, losing ~1/3 of the water volume and ~70% of its surface during the most extreme events. The remaining water was stored in a central salt-lake and peripheral desalinated basins while vast regions (up to 1.75 million km2) became emerged land, suitable for the development of forest-steppe landscapes. The dry episodes of the megalake match with climate, food-web and landscape changes throughout Eurasia but the exact triggers and mechanisms remain to be resolved.</p>

The upper Miocene – lower Pliocene sedimentary succession of the Denizli Basin (SW Anatolia) displays a unique record of undisturbed stratigraphy and provides an excellent opportunity to study long-term palaeoecological changes. This paper documents the ostracod assemblages of two sections of the Neogene Kolankaya Formation, resulting in the following taxonomic, palaeobiogeographic and ecological interpretations. The ostracod assemblages from the two sections consist of a mixture of oligohaline to mesohaline tolerant taxa but expose fundamental differences in their composition. This is reflected by the fact that out of 32 determined species, both sections only have 3 in common. In the stratigraphic older succession, the diverse ostracod fauna resembles taxa known from the Paratethys. Faunal relations to the brackish lake habitats of the Euxinic and Pannonian basins are apparent and the palaeobiogeographic significance of the fauna is discussed. The ostracod association of the younge...

<p>The discovery in the 70’s of the km-thick Mediterranean salt giant alongside the seismic observance of Pliocene-filled engravings along its shelf-slope systems concurred together to postulate that the Mediterranean-Atlantic seaway terminated during the late Messinian. The resulting changes in paleogeographic, paleohydrological and biological conditions, acknowledged as Messinian Salinity Crisis (MSC, 5.97-5.33 Ma), find their expression in the marginal sedimentary record in fauna-depleted gypsum and halite-bearing successions (5.97-5.42 Ma). During the Lago-Mare phase (5.42-5.33) that terminates the MSC the evaporitic deposition endures in the intermediate basins (e.g. Caltanissetta Basin, Sicily), whilst all the marginal basins fill with fluvio-lacustrine terrigenous sediments. Up to five conglomerate to sandstone-laminated pelite alternations thought to be precession controlled are counted underneath the Zanclean marine deposits featuring the restoration of a marine environment. Finer hemicycles tuned to insolation maxima period stand out above all for the occurrence of faunal assemblages consisting of brackish water ostracods, mollusks and dinoflagellate cysts. The affinity of these faunal elements with the coeval inhabitants of the Eastern Paratethys region, fragmented in isolated, long-lived brackish lakes (i.e. Euxinic and Caspian Basin), led to the primordial hypothesis of a similar paleoenvironment in force during the Lago-Mare phase for the Mediterranean, coherent with the paleoenvironment subsisting immediately prior to it. However, the progress of scientific research provided additional evidence arguing against the desiccation theory and supporting a basin filled even during the Lago-Mare phase. Within the full Mediterranean model controversial views exist on the hydrochemistry of the water mass, disputed between marine, brackish and density-stratified. To elucidate Mediterranean base level and hydrology just preceding the restoration of open marine conditions we merge together new and published ostracod biostratigraphic data and radiogenic strontium isotope ratios (<sup>87</sup>Sr/<sup>86</sup>Sr) from locations (SE Spain, Piedmont, Sicily and Cyprus) covering the whole extent of the Mediterranean Basin. Ostracod faunal assemblages share approximately the same species and the same distribution pattern. Within a single pelitic bed, richness varies from oligotypic assemblages dominated by <em>Cyprideis torosa</em> to heterotypic assemblages with up to 17 Black Sea-derived species. Consequently, we conclude that it is most likely that the Mediterranean water level during the final phase of the MSC was high enough to let the Paratethyan fauna to reach and spread throughout the shallow Mediterranean depositional environments. <sup>87</sup>Sr/<sup>86</sup>Sr ratios measured on ostracod valves range between 0.709131-0.708715. The generally lower and higher Sr isotopic composition than contemporary seawater (∼0.709024) alongside the data spreading are considered as a further proof of the presence of multiple lakes acquiring their own isotopic composition. We demonstrate that, when taken individually, none of the marginal basins yields an isotopic signature that matches that of the local rivers. If anything, these…

ABSTRACT Biodiversity and conservation assessments rise and fall with taxonomic accuracy. An example of a still largely unresolved taxonomy is found in the Gastropoda of the Caspian Sea. The present paper clarifies the taxonomy of the genus Abeskunus and its three species of anomalohaline gastropods endemic to the Caspian Sea. Based on material from Pleistocene, Holocene, and (sub-)recent deposits from Russia, Azerbaijan, and Kazakhstan we discuss species discriminations, synonyms, systematic position, as well as uncertainties regarding the type species. Given the apparent loss of all type material, we designate neotypes for all three species. Despite our efforts to collect and analyse new material and available material housed in museum collections, molecular data, and soft-part anatomy are unavailable precluding a firm systematic classification. Overall shell morphology and protoconch microsculpture are indicative of the family Lithoglyphidae. Comparison with Miocene and Pliocene fossils attributed to the genus Zagrabica suggests it to be a likely ancestor of Abeskunus, tracing back the lineage to the late Miocene Lake Pannon. Although the recent literature lists all three species of Abeskunus among the extant Pontocaspian fauna, two of the three species have never been found living and the third one not since the nineteenth century.

The semi-isolated epicontinental Paratethys Sea in the Eurasian continental interior was highly sensitive to changes in basin connectivity and hydrological budget. The Caspian Sea, the easternmost basin experienced a five-fold increase in surface area during the Plio-Pleistocene climate transition, but a basic process-based understanding is severely hampered by a lack of high-resolution age constraints. Here, we present a magnetostratigraphic age model supported by 40 Ar/ 39 Ar dating of volcanic ash layers for the 1600 m thick Jeirankechmez section in Azerbaijan that comprises a sedimentary rock succession covering this so-called Akchagylian flooding. We establish the age of this major change in Caspian paleohydrology at around 2.7 Ma. The presence of cold water foraminifera, rising strontium isotope ratios and the possible arrival of the enigmatic Caspian seal in the basin hints at an Arctic marine source for the Akchagylian waters. The new age model indicates a direct link to the intensification of northern hemisphere glaciations at the end of the Pliocene and to concurrent hydrological shifts across Eurasia, such as the onset of cyclic Chinese Loess deposits. The transformation of the Paratethys region around 2.7 Ma from a series of small Pliocene endorheic lake basins to a large Early Pleistocene epicontinental water mass coincides with a more positive hydrological budget for the Eurasian continental interior. The drainage of additional high latitude, low salinity water to the Mediterranean, may have contributed towards variability in global paleoceanography, and could potentially provide a positive feedback towards Pleistocene climate cooling.

Examination of normal pore canals, especially sieve-type pore canals, in living and fossil representatives of ten genera of the family Limnocytheridae, subfamily Timiriaseviinae, has revealed important diversity of structure. These complex pore canals have been studied via high-resolution scanning electron microscopy (the Cartographic Method) and analysed via the application of newly devised indices to assess patterns of consistency and variation in both detailed structure of individual pores and of their distribution on the calcified valve. The timiriaseviine taxa are compared with species of the genera Limnocythere, sub-family Limnocytherinae and Cyprideis (family Cytherideidae). The relationship between the living animal and its aquatic environment is discussed in the light of previous studies and of new evidence herein. The importance of normal pore canals for systematics is highlighted by the recognition and definition of the new tribe Gomphodellini Danielopol, Cabral Lord nov....

ABSTRACT Badenian calcareous nannofossils have been investigated from two outcrops situated at the southern end of the Eastern Carpathians. Both qualitative and quantitative nannofloral analyses have been performed. In the Slănic Formation, below the ‘Evaporitic Formation’, the calcareous nannoplankton standard zone NN5 has been recorded within the oldest part, mainly made by marlstones and claystones, interbedded with levels rich in Globigerina foraminiferal tests and with tuffitic layers; towards the top of this unit, above the youngest Globigerina marly level, where the tuffs are prevailing, the NN6 zone has been recognized. The aforementioned nannofossil zone has been also recorded above the ‘Evaporitic Formation’, in the ‘Radiolarian Shale’ Formation. Hence, the Badenian Salinity Crisis of the Eastern Carpathians is constrained by the LO (last occurrence) of Sphenolithus heteromorphus and the LO of Cyclicargolithus floridanus, being placed within the NN6 calcareous nannofossil zone. Below the Badenian Salinity Crisis, in the NN5 zone, the nannofloras are dominated by the Sphenolithus and Discoaster genera that characterised warm surface waters. The abundance of these taxa starts to gently decrease from the base of the NN6 zone, below the Badenian Salinity Crisis, but a more significant shift has been encountered above this salinity crisis, where a bloom of Braarudosphaera bigelowii, reaching 20 % of nannofloral assemblages, has been identified. This calcareous nannofossil event is possibly linked to the end of the Badenian Salinity Crisis in the Eastern Carpathians, involving a decrease in the salinity of water-surface together with a significant influx of fresh water into the Carpathian basin.

Abstract Prior to the onset of the Messinian Salinity Crisis, a connection was established between the Mediterranean Sea and the Paratethys region to the north. Rivers currently draining into the Caspian Sea thereby became important for the Mediterranean hydrological budget. The role of this connection and the influence of the Paratethys on the hydrological budget of the Mediterranean Sea during the Messinian Salinity Crisis is however poorly understood because of a lack of records in the Paratethys with a high-resolution (cyclostratigraphic) age model. Here, we present a high-resolution integrated stratigraphic study of a key section in the Caspian Sea region (Azerbaijan), to assess the connectivity of the Caspian Sea during the salinity crisis. The studied section spans the time interval between ~ 6.16 Ma and

Abstract A gigantic cascade of Atlantic waters, filling the deep desiccated Mediterranean basin at the beginning of the Pliocene, has commonly been envisaged to end the Messinian Salinity Crisis (MSC). The Mediterranean lowstand during its final “Lago-Mare” phase, however, has long been subject to major controversy and has recently been seriously questioned again. Here, we present high-resolution ostracod distribution patterns of the MSC successions in the Black Sea basin (Zheleznyi Rog section; Russia) and the Mediterranean (Cuevas del Almanzora section; Spain) to study the origin and migration history of the Lago-Mare ostracods. We conclude that two major phases of faunal migration have taken place in the Messinian. The first phase corresponds to the Maeotian–Pontian boundary interval (~ 6.1–6.0 Ma) of the Paratethys, where mainly Pannonian species suddenly invaded the Black Sea region. The second migration event corresponds to the Lago-Mare phase of the Mediterranean when first (5.55–5.47 Ma) some opportunistic taxa (species of Cyprideis and Loxoconcha genera) and then (5.40–5.33 Ma) a more diverse assemblage of Paratethyan species occupied the entire Mediterranean region. The Spanish ostracod assemblages show a high percentage of Paratethyan (Pontian) ostracods, in agreement with previously studied Italian Lago-Mare sections. The similar palaeoenvironmental changes that developed roughly synchronously in the western and central Mediterranean marginal basins provide more evidence for intrabasinal exchange at high water level during the final stage of the Lago-Mare phase. This indicates that the Mediterranean in the latest Messinian was full of water (comparable to the present Caspian Sea) and that the Zanclean deluge, if happened, only surged some tens, up to few hundred metres, into the Mediterranean.

A newly proposed biostratigraphic zonation of Early Cretaceous microfossils (mainly foraminifera) improved the resolution for dating the shelf carbonate platform deposits from Cernavodă-lock section, South Dobrogea, eastern part of the Moesian Platform. The zonation comprises 12 zones (biozones) for the Upper Berriasian-Valanginian-Lower Hauterivian. Benthic foraminifers marker are represented by Protopeneroplis ultragranulata, Andersenolina elongata, Dobrogelina anastasiui (Upper Berriasian), Haplophragmoides joukowski, Montsalevia salevensis, Carasuella cylindrica (Lower Valanginian), Danubiella gracilima, Rumanoloculina robusta, Meandrospira favrei (Upper Valanginian), respectively Protopeneroplis banatica, Vercorsella tenuis, Moesiloculina danubiana (Lower Hauterivian). The new biozonation scheme has allowed correlation of the studied succession with other major paleogeographic realms on the Romanian territory, in the eastern part of the Moesian Platform including South Dobrogea...

ABSTRACT The studied Cernatu Valley section is situated in the central part of the Eastern Carpathians (Romania) and spans the interval covered pro parte by the NC10a (¼CC9b) calcareous nannofossil Subzone, as well as the Plectorecurvoides alternans and Haplophragmoides falcatosuturalis agglutinated foraminiferal zones. The presence, within the lower part of the section, of the ammonite Stoliczkaia notha indicates a late Albian age, but the section possibly extends to within the Albian-Cenomanian boundary interval, based on the agglutinated foraminiferal assemblages. The deposits are grey to blackish and green shales that are followed by red shales interbedded with couplets of grey to blackish and green shales. The benthic foraminifers suggest a deep-marine depositional setting, probably lower bathyal or even abyssal, at around 2500 m depth. The deposition was probably near but above the Calcium Compensation Depth (CCD), as very scarce nannofloras and macrofaunas are present. The d13C values vary throughout the section between �25.30 ‰ and �24.01‰. Within the upper Albian, a positive 13C excursion with increases of 1.3 ‰,upto�24.01‰, is recorded. This positive excursion has been tentatively interpreted as a regional expression of the Oceanic Anoxic Event OAE1d in the Moldavian Trough of the Eastern Carpathian basin. The upper part of the section, belonging to the Haplophragmoides falcatosuturalis agglutinated foraminiferal Zone, contains a weak positive d 13 C excursion marked by an increase in values of about 0.5 ‰, which is assumed to represent late phases of the Albian-Cenomanian boundary Event. Towards the top of the section, consisting mainly of red shales, calcareous foraminifera also occur, together with more consistent nannofossil assemblages. This biotic change possibly mirrored an alteration of the palaeoenvironment, which shifted from an anoxic/dysoxic setting towards an oxic one. This change is possibly linked to climatic fluctuation, i.e., the onset of a warm and humid climate mode. The intense tectonic activity that took place within the Eastern Carpathians during mid-Cretaceous times could also have been responsible for the environmental changes by modifying the circulation pattern in the Moldavian trough from a restricted circulation to a more open one.

The Tarim Basin in western China formed the easternmost margin of a shallow epicontinental sea that extended across Eurasia and was well-connected to the western Tethys during the Paleogene. Climate modeling studies suggest that the westward retreat of this sea from Central Asia may have been as important as the Tibetan Plateau uplift in forcing aridification and monsoon intensification in the Asian continental interior due to the redistribution of the land-sea thermal contrast. However, testing of this hypothesis is hindered by poor constraints on the timing and precise paleogeographic dynamics of the retreat. Here we present an improved integrated bio- and magnetostratigraphic chronological framework of the previously studied marine to continental transition in the southwest Tarim Basin along the Pamir and West Kunlun Shan, allowing us to better constrain its timing, cause and paleoenvironmental impact. The sea retreat is assigned a latest Lutetian-earliest Bartonian age (~41 Ma; ...

The landslide that is the subject of this paper occurred in the central part of Romania, in Prahova County, located near the Prahova Valley, in hillside area, frequently affected by this kind of major hazard. The geological phenomenon occurred in the area is an old event and it was reactivated starting with 2010. The inappropriate geological and geotechnical conditions characteristic of the area and also the lack of a drainage system were conducted to landslide reactivation during a period of intense rainfall. The present work was carried out to study the spatial influence of geological and morphological factors upon landslide occurrence on a local scale by using geotechnical and geophysical methods in order to determine local trigger parameters. The complex studies were conducted in finding the most feasible technical and economical option for the efficient emergency management of landslide hazard.

ABSTRACT A source to sink systemdescribes the natural link betweenmountains, plains and deltas, by analysing the (re)distribution of material at shallow crustal depth and at the Earth's surface, exploring the links between coupled tectonic and surface processes. Sediment fluxes are the product of erosion and movement of material in and from sources (mountains), the transport and movement of sediments and solutes by river systems to the plains, and deposition and storage in sink zones. The ESF-EUROCORES TOPO-EUROPE SourceSink programme is a fully integrated research effort to significantly advance our predictive capabilities on the quantitative analyses of coupled active and past drainage systems by means of step-wise 4D reconstructions of sedimentsmass transfer, integrating geophysics, geology, geomorphology, state of the art high-resolution dating, and numerical and analogue modelling. The area selected for this programme is the Danube River Basin–Black Sea source to sink system, a world-class natural laboratory that is uniquely suited in the heart of Europe's topography, covering almost half of its surface, providing opportunities for excellent field sites to study in integration surface and subsurface data that cover the complete chain of source, carrier and sink. Quantifying andmodelling the complete system in relation to the controlling parameters has resulted in significant understanding of forcing factors and linking temporal and spatial scales across multiple orogen and basin systems. This research has provided the opportunity to widen the geographical scope to other natural scenarios, where a number of mountain chains with similar geodynamic genesis separate sedimentary basins with comparable evolution.

ABSTRACT The paleogeographical and geological evolution of the Dacian Basin (and Eastern Paratethys, in general) during the Late Maeotian and Pontian is frequently discussed on the geological literature, because at this time interval in the Mediterranean area experienced its so-called Messinian Salinity Crisis (MSC) (Floroiu et al., 2011). Many authors consider that this event had more or less dramatically effects in adjacent basins of the Paratethys including the Dacian Basin. The main effects of the connections or disconnections of Paratethys with the open seas consist in changing the bathymetry and the salinity of paratethyan basins. The marginal areas of the Dacian Basin are more sensitive to water level variations in the basin. Our biostratigraphic results from the several sections located in the marginal area of the Dacian Basin show that the fossil ostracod assemblages from the Upper Maeotian comprise a low number of species, Cyprideis pannonica being the dominate one. These fossil assemblages are indicative of sub-littoral fresh- to brackish water environment, suggesting that the Upper Maeotian sediments in the east Carpathian foredeep are associated with temporary lakes on flood plain areas. During the Late Maeotian, close to the boundary with the Pontian stage, an important transgressive event can be noticed in the Dacian Basin and in all over the Eastern Paratethys basins (Krijgsman et al., 2010). We recognized in this interval few levels rich in Congeria (Andrusoviconca) amygadaloides novorossica shells and some benthic (agglutinated, calcareous) and planktonic foraminifers. The presence of foraminifers proved that this transgressive moment at Maeotian / Pontian boundary is accompanied by increasing of water salinity. Magnetostratigraphic results show that this flooding interval occurred synchronously in the Dacian and Black Sea basins near the paleomagnetic reversal C3An.2n(y), and is dated at 6.04 Ma (Krijgsman, et al., 2010, Stoica et al., submitted). After the trangressive moment, the Lower Pontian (Odessian) fauna is represented by a "bloom" of ostracods species: Pontoniella (Zalanyiella) acuminata, P. (Serbiella) striata, Candona (Hastacadona) lotzyi, C. (H) hysterica, C. (Zalanyiella) venusta, C. (Caspiocypris) alta, C. (C.) pontica, C. (Camptocypria) ossoinaensis, Cypria tocorjescui, Bakunella dorsoarcuata, Cytherissa sp., Tyrrhenocythere pannonicum, Leptocythere cymbula, L. (Amnicythere) andrusovi and Pontoleberis pontica. We conclude that the Maeotian / Pontian boundary in the Dacian Basin is marked by a trangressive moment related to briefly restore the connection between the Eastern Paratethys and Mediterranean, or alternatively with the Indian Ocean.