the messinian salinity crisis in the dacic basin sw romania and early zanclean mediterranean eastern paratethys high sea level connection new field observations and fossil analyses complete and clarify the strong impact of the mediterranean sea level changes linked to the peak of the messinian salinity crisis on the dacic basin in southwestern romania in addition to the gilbert type fan delta already evidenced along the danube river in the area of turnu severin a new gilbert type fan delta is described northward early zanclean bottomset beds are evidenced and dated based on nannofossils at the junction of the two coalescing gilbert type fan deltas a clear sedimentological morphological and chronologic differentiation is established in the area between the carpathians late miocene piedmont alluvial fans and the early zanclean gilbert type fan deltas the early zanclean age of the hinova clays where the bottomset beds of the gilbert type fan deltas are mostly developed is confirmed by the occurrence of nannofossil markers of subzone nn12b and a bosphorian mollusk macrofauna early zanclean inflow of mediterranean marine waters into the dacic basin is also supported by the record of planktonic foraminifers in the dacic basin the messinian salinity crisis resulted in the cutting of the iron gates by a carpathians river fluvial erosion also affected the residual pannonian basin and probably catched the paleo tisza river which contributed to the erosion of the iron gates and to the fluvial drainage of the partly desiccated dacic basin arguments are reinforced in favor of a marine gateway between the mediterranean and dacic basin through the balkans before and after the messinian salinity crisis

mio pliocene magnetostratigraphy in the southern carpathian foredeep and mediterranean paratethys correlations a full understanding of the mio pliocene palaeogeographical and palaeoenvironmental changes in the circum mediterranean region during the messinian salinity crisis msc is at present hampered by the lack of reliable chronostratigraphic correlations between the mediterranean and paratethys regions here we present magnetostratigraphic ages for the upper miocene to pliocene deposits of the southern carpathian foredeep in romania these ages are in good agreement with those recently obtained from the eastern carpathian foredeep and define a new chronology for the eastern paratethys the meotian pontian boundary is not biostratigraphically

messinian erosional and salinity crises view from the provence basin gulf of lions western mediterranean abstract though the late miocene messinian salinity crisis has been intensely researched along the circum mediterranean basins few studies have focused on the central part of the mediterranean basin and especially the pre salt deposits to improve our knowledge of the messinian events it is imperative to better understand this domain in this study we provide a more complete understanding of this central domain in the provence basin we were able to recognize a thick marine detrital series up to 1000 m derived from the messinian subaerial erosion which is partly prolongated in the distal part by b a thick unit of deep marine deposits up to 800 m prior to the evaporites c a thick presumed alternation of detritals and evaporites 1500 m below the mobile halite and d a two step transgression at the end of the messinian spatially we document the eroded shelf to the deep basin and from the western to the eastern parts of the gulf of lions and temporally we extend the interpretations from the early deposition of detritic sediments to the final sea level rise the results provide a new basis for discussion not only for the development of the messinian salinity crisis but also for the reconstruction of the subsidence history of the provence basin

discussion on large sea small tides the late carboniferous seaway of nw europe roger higgs writes wells et al 2005 a b produced an innovative and thought provoking numerical model of tides in the late carboniferous seaway of nw europe predicting very low tidal ranges 1 m consistent with the scarcity of sedimentary evidence for weak tides reported in the corresponding rocks based on the model wells et al 2005 a argued intuitively that tidal range was minimum during glacioeustatic highstands and maximum during lowstands and transgressions i would argue the converse during highstands not only was the water volume mass greater leading potentially to larger tides but also any tide in the adjacent ocean would necessarily be passed into the seaway adding to the locally generated tide this is a weakness of the model the oceanic tidal influence was not incorporated for simplicity wells et al 2005 a p 418 in contrast during lowstands the seaway became a freshwater lake or chain of lakes perched at the level of the outflow sill and bordered by incised highstand prograded deltas and alluvial plains lake bude of higgs 1991 2004 disconnected from the global ocean the lake would have had an extremely low tidal range 5 cm as in all lakes because of the relatively small water volume talbot allen 1996 indeed no evidence for tides has been reported in lake bude deposits ross crackington and bude formations of ireland and england higgs 1991 2004 and references therein however given the scarce evidence reported elsewhere in the seaway sedimentary structures indicative of weak tidal currents e g ripples with foreset slack water mud drapes rhythmic lamination opposed ripples may eventually be discovered in the lake bude formations probably associated with the volumetrically minor shale bands with brackish and marine fossils higgs 1991 2004 representing transgressions and highstands when

evolution of the transport direction of the carpathian belt during its collision with the east european platform the evolution of the carpathians is in its final stage with intermediate seismic activity 70 200 km mw 4 7 7 localized beneath its southeastern salient vrancea zone our analysis in the transition area between south carpathians and east carpathians reveals that the termination of convergence is characterized by a clockwise rotation of the carpathian belt transport direction using structural maps and cross sections we show that this change of convergence direction had several structural consequences including 1 the pliocene quaternary activation of out of sequence structures in the southern east carpathians and 2 the creation of dextral strike slip faults bounding the mobile belt to the west in the south carpathians our fracture analysis in syntectonic deposits allows us to distinguish and stratigraphically date two fanning stress patterns corresponding to the two last transport directions of the carpathian system 1 a burdigalian to early tortonian stress field with compression directions rotating along with the carpathian curved orogenic belt but with transpression nw se compression and a low strain partitioning along east trending internal strike slip faults in the south carpathians and 2 a late tortonian to pleistocene rotated and smaller radial stress pattern with n s compression in the south carpathians the rotation of the convergence direction is interpreted as the result of the miocene migration and progressive collision of the carpathian system with the thick crust of the nw trending tornquist teisseyre line and its prolongation in romania the area able to subduct determined by thickness of crust entering the subduction zone was progressively restricted to a foreland corner in front of the southeastern carpathians the progressive collision forced the convergence to slow down and rotate from eastward to southeastward in late miocene the dobrogea hills in front of the latest migrating system may represent the late neogene ne sw flexural bulge of the subducting foreland panel this clockwise rotation of the transport direction can be compared with the clockwise rotation that occurred in other subduction systems tyrrhenian subduction caribbean subduction etc which were controlled by the location of oceanic versus continental crust in front of the orogenic belt

tectonosedimentary evolution related to extreme crustal thinning ahead of a propagating ocean example of the western pyrenees 1 in this paper we describe the tectonosedimentary evolution and its subsequent inversion of a basin that underwent extreme crustal thinning in a transtensional setting ahead of a propagating ocean in the western pyrenees the labourd mauleon area situated in the western pyrenees at the termination of the v shaped bay of biscay is an ideal natural laboratory to study how such complex basins evolve in time and space because of a mild inversion of the basin during pyrenean compression the rift structures and their relations to basement rocks and sediments are exposed and can be directly studied in the field the basin shows a complex polyphase evolution that starts with left lateral dominated transtension in latest jurassic early aptian time this event is overprinted by a late aptian early albian extension that is related to the counterclockwise rotation of iberia away from europe leading to the opening of the bay of biscay during this stage the late triassic to jurassic carbonate platform was stretched salt migrated and detachment faults exhumed upper and lower crustal and mantle rocks to the seafloor the final structure of the basin resembles a sag basin floored by exhumed rocks overlain by extensional allochthons and compartmentalized by n40 to n60 transfer faults the sedimentary architecture is characterized by late aptian synrift sediments e g urgonian limestones that were deposited in fault bounded basins and are overlain by thick latest aptian to albo cenomanian sediments e g flysch noir that define a sag sequence the complex tectonosedimentary evolution of the basin is associated with salt tectonics and overprinted by a major magmatic thermal event that postdates mantle exhumation

microseismicity of the bearn range reactivation of inversion and collision structures at the northern edge of the iberian plate the bearn range located to the north of the axial zone in the western pyrenees is affected by numerous small magnitude seismic events these events overlap an area characterised by specific geological structures which are interpreted to have resulted from multistage extensional and compressional deformation an analysis of surface geology draped over dem together with field investigations allow identification of two main shortening episodes with differing direction of contraction d1 represents the inversion of the north pyrenean basin whose mesozoic infill was detached from highly extended crust and transported southwards over the necking zone and the northern margin of the iberian plate d2 corresponds to the collision stage and is characterised in the study area by backfolding and backthrusting deformation coeval with uplift in the axial part of the chain due to thickening of the iberian plate the microseismicity appears to concentrate along the basal part of the inverted basin units d1 where this initially low angle thrust has been tilted and steepened during collision d2 we propose that local steepening of this ancient inversion structure which should not be named north pyrenean fault provided the suitable dip for extensional solicitation in association with the present uplift of the axial zone whatever the driving mechanism of this uplift could be

the berit transect of the tauride thrust belt s turkey late cretaceous early cenozoic accretionary collisional processes related to closure of the southern neotethys abstract we report on an integrated study of a critical segment of the tauride thrust belt in se turkey berit area units related to two sutures are exposed in the northerly and southerly parts of the area studied in the north the upper cretaceous binboga melange reflects the closure of a northerly mesozoic oceanic basin in the south contrasting units document the closure of the southern neotethys in the south the berit or goksun ophiolite formed as an incipient oceanic arc within the southern neotethys during the late cretaceous c 90 ma intercalated amphibolite granulite facies rocks may record a dismembered metamorphic sole an underlying meta sedimentary meta volcanic unit is interpreted as accreted continental rift and oceanic seamount lithologies the berit ophiolite was accreted to the tauride active continental margin to the north around 85 ma and was then intruded by calc alkaline granites c 70 85 ma northerly margin units were exhumed and covered by shelf carbonate sediments during latest cretaceous early cenozoic time northward subduction during the mid cenozoic c 45 ma resulted in back arc extension along the tauride active margin and subduction influenced volcanism possibly controlled by slab roll back during oligocene early miocene time the southern neotethys closed and the tauride active margin was telescoped to create the present south vergent thrust stack this was accompanied by mass wasting of the advancing allochthon to form sub aqueous frontal olistostromes the arabian platform was over ridden by mid miocene time followed by left lateral strike slip along the east anatolian fault zone as anatolia began to escape westwards towards the aegean sea

structural and depositional evolution of the east balkan thrust belt bulgaria analysis of structural and sedimentologic data from onshore outcrops offshore wells and offshore seismic profiles indicates that the thrust belt geometry in eastern bulgaria from the paleocene to the holocene is characterized by a southeastward plunge toward the western black sea basin this plunge was caused by 1 a combination of eastward thinning continental crust in the west and oceanic crust in the east 2 a postrift thermal subsidence of the continental crust 3 buttressing and no buttressing of the moesian platform against the thrust belt in its western and eastern parts respectively and 4 northeastward thrust belt advance these factors controlled the overall eastward diminishing uplift of the thrust belt and associated eastward sediment funneling into the black sea evidence for the eastward fading uplift and buttressing includes the 1 eastward decreasing amount of shortening along constructed cross sections yielding 30 10 5 11 and 4 km 18 6 6 5 6 8 and 2 5 mi respectively from west to east respectively 2 eastward trend of more complete stratigraphic sections and shallower erosional levels and 3 eastward increase in decollement depths being 3 7 3 8 9 5 to 13 5 and 12 3 to 14 1 km 2 3 2 4 5 9 8 4 and 7 6 8 8 mi the age of the last thrusting is progressively younger toward the east from the middle eocene through the late eocene to the oligocene from west to east respectively onshore parts of the thrust belt which were significantly affected by buttressing against the moesian platform exhibit thrusting followed by late eocene gravitational collapse oligocene quiescence and neogene extension the thrust belt part farther east exhibits thrusting followed by oligocene neogene extension a paleocene middle eocene piggyback basin formed in the onshore part of the thrust belt centered in the east balkan zone with a southeastward plunging axis which migrated northeastward with basin shortening and filling the development of the east balkan thrust belt and its later extensional modification had a dominant control over sediment transport lithofacies and depositional patterns developing thrust belt fold structures together with the orogenic hinterland and highs in the foreland formed a northeastward and eastward expanding system of sediment input southeastward plunging axes of the foreland basin and the paleocene middle eocene piggyback basin were the principal sediment transport pathways together with subordinate internal synclinal axes these depressions funneled sediments toward and into the western black sea basin as orogenesis advanced to the northeast former depositional areas were uplifted and eroded providing local sources of sediment

impact of the messinian salinity crisis on black sea hydrology insights from hydrogen isotopes analysis on biomarkers the messinian salinity crisis 5 96 5 33 ma ago was a dramatic oceanographic event when evaporites kilometers thick precipitated in a desiccating mediterranean basin trapping more than 5 of the world s oceanic salt hydrological changes in the adjacent black sea and water exchange with the mediterranean region are crucial but poorly understood factors influencing messinian evaporite formation here we present compound specific hydrogen isotope d data from messinian black sea sedimentary rocks that show a rapid change to heavy waters at 5 8 ma when major glaciations occurred at the same time highly depleted d values of long chain n alkanes derived from plant waxes indicate that fresh river transported water originated from colder northern latitudes the d values of alkenones biosynthesized by haptophyte algae show an unprecedented increase of 60 within 100 kyr the corresponding rapid change to 110 for d of the black sea waters seem unrealistic being heavier than anywhere in the present day oceans regardless of the applied relation between the d values of the alkenones and d of the waters where they were produced the 60 enrichment in the d values of alkenones indicates strongly enhanced evaporitic conditions still the relative distribution of the alkenones implies in situ growth and reproduction of haptophyte algae requiring sustained marine conditions in the black sea up to 5 6 ma this indicates that mediterranean black sea connectivity persisted during the first msc phase when gypsum precipitated in the mediterranean basin when the black sea became isolated at the peak of the msc 5 6 ma it had a strongly negative hydrological budget and rapidly desiccated due to excess evaporation

upper plate magma poor rifted margins stratigraphic architecture and structural evolution abstract although it is generally accepted that many distal magma poor rifted margins are asymmetric and can be divided into lower and upper plate margins little is known about the details of how and when this asymmetry evolves and how upper and lower plate margins can be distinguished this is due to the fact that most papers focused on the so called lower plate margins while the upper plate margins remained less well understood mainly due to the lack of public accessible drill hole data the aim of this paper is to provide a first order description of the global architecture and stratigraphic evolution of an upper plate magma poor rifted margin in order to provide such a template we focused on 2 seismic sections the ion 1000 line east indian margin and the screech 2 line newfoundland margin and describe key km scale outcrops from the fossil european margin exposed in the western central alps all of which document classical upper plate margins based on these data we show that upper plate magma poor rifted margins can be characterized by a staircase type architecture with terraces t 1 t 2 t 3 and ramps r 1 r 2 that result as a consequence of an evolution through a coupling exhumation and breakup stage we also defined key stratigraphic levels that we try to link with the evolution of the margin which enables us to link the tectonic evolution with the creation of accommodation space and formation of the staircase architecture that characterizes the upper plate margin from these observations we develop a conceptual model for the evolution of upper plate margins and discuss the applicability of this model for different strain rates rates of subsidence and sedimentation rates

messinian sea level fall in the dacic basin eastern paratethys palaeogeographical implications from seismic sequence stratigraphy the signature of the mediterranean messinian salinity crisis msc in the paratethys has received wide attention because of the inferred changes in connectivity and base level in this article we present sequence stratigraphic interpretations on a seismic transect across the western part of the semi isolated late miocene pliocene dacic basin eastern paratethys romania chronologically constrained by biostratigraphic field observations and well data they reveal significant sea level changes during the middle pontian that are coeval with the msc these changes were most likely transmitted to the western dacic basin from the downstream black sea and controlled by the sill height of the interconnecting gateway during the middle pontian lowstand of the western dacian basin sedimentation continued in a remnant 300 m deep lake with a positive water balance our observations show that the evolution of semi isolated sedimentary basins is strongly dependent on the communication with other depositional realms through its control on base level and sediment supply

structural evolution of the eastern balkans bulgaria abstract the balkans are an e w trending thrust belt mainly of palaeogene age generated by a left lateral transpression with maximum stress oriented n30 e the transpressive nature of the balkans may be deduced from the en echelon pattern of folds and thrusts which is due to oblique shortening with respect to pre existing mesozoic e w trending crustal anisotropies between the moesia platform and the balkans basin the front of the eastern balkans is marked by the chudnite skali ajtos thrust during the neogene and quaternary the balkans were inverted by right lateral transtensional tectonics which cross cut and dismembered the thrust belt the main transtensional segment is the southern margin of the balkans e g the emine line the steep transtensional faults disconnected the thrust planes of the balkans from the thrusts of the srednogorie to the south grabens are in general asymmetrical with master faults dipping 80 40 south westward and probably flattening into the middle crust the structural evolution of the balkans may also be traced into the black sea but the structural trends gradually change from the e w trend to a nw se strike indicating pure palaeogene compression and more recent neogene extension inverting and cross cutting the compressive features it is also interesting to note that the neogene tensional or transtensional inversion is not cylindrical it exhibits undulations of graben and transfer faults controlled by the pre existing compressive fabric the eastern balkans and their continuation in the black sea are morphologically and structurally deeper and they plunge eastward and south eastward towards the black sea this is due both to the deeper position of the balkans de collement planes in the black sea and to the thermal subsidence along the black sea continental margin

late palaeozoic early cenozoic tectonic development of the eastern pontides artvin area turkey stages of closure of tethys along the southern margin of eurasia

dating of the black sea basin new nannoplankton ages from its inverted margin in the central pontides turkey the eocene uplift and inversion of a part of the black sea margin in the central pontides allows to study the stratigraphic sequence of the western black sea basin the revision of this sequence with 164 nannoplankton ages indicates that subsidence and rifting started in the upper barremian and accelerated during the aptian the rifting of the western black sea basin lasted about 40 myr from late barremian to coniacian in the inner inverted black sea margin the syn rift sequence ends up with shallow marine sands the uppermost albian to turonian was a period of erosion or non deposition this regional mid cretaceous stratigraphical gap might result from rift flank uplift as expected in the case of a thick and cold pre rift lithosphere however coeval collision of the kargi block along the north tethyan subduction zone at the southern margin of the pontides might also have contributed to this uplift a rapid thermal post rift subsidence of the margin occurred during the coniacian santonian collision of the kirsehir continental block commenced in early eocene time zone np12 giving rise to compressional deformation and sedimentation in piggyback basins in the central pontides whereas the eastern black sea was still opening

the role of the bay of biscay mesozoic extensional structure in the configuration of the pyrenean orogen constraints from the marconi deep seismic reflection survey 1 seismic interpretation of the marconi deep seismic survey enables recognition of the upper crustal structure of the eastern part of the bay of biscay and the main features of its alpine geodynamic evolution the new data denotes that two domains with different pyrenean and north foreland structures exist in the bay of biscay in the eastern or basque parentis domain the north pyrenean front is located close to the spanish coast and the northern foreland of the pyrenees is constituted by a continental crust thinned by a north dipping fault that induced the formation of the early cretaceous parentis basin in the western or cantabrian domain the north pyrenean front is shifted to the north and deforms a narrower and deeper foreland basin which lies on the top of a transitional crust formed from the exhumation of lithospheric mantle along a south dipping extensional low angle fault during the early cretaceous the transition between these two domains corresponds to a soft transfer zone linking the shifted north pyrenean fronts and a north to wnw directed thrust that places the continental crust of the landes plateau over the transitional crust of the bay of biscay abyssal plain comparison between this structure and regional data enables characterization of the extensional rift system developed between iberia and eurasia during the late jurassic and cretaceous and recognizes that this rift system controlled not only the location and features of the pyrenean thrust sheets but also the overall structure of this orogen

palaeozoic terranes and their lithospheric boundaries within the trans european suture zone tesz a review the trans european suture zone tesz is a broad and complex zone of terrane accretion separating ancient lithosphere of the baltic shield and east european craton eec from the younger lithosphere of western and southern europe there is debate about the number of terranes involved and their origins the most significant terrane boundaries originally oceanic sutures are poorly exposed and are defined using faunal provinciality prominent geophysical lineaments may represent sub terrane boundaries within composite terranes the avalonia composite terrane was amalgamated to baltica in latest ician time the provenance of the malopolska and moravo silesian terranes whose neoproterozoic basement is suspect with respect to baltica but with which they nonetheless share faunal affinities is still debated the extent of the variscide rhenohercynian zone defines the southern limit of the early palaeozoic accreted terranes terranes within the bohemian massif exhibit hp metamorphism recording subduction driven collision prior to incorporation in the tesz collage itself associated with a hp event in romania the saxothuringian zone and rheic suture are directly juxtaposed with the eec and the crustal structure of the tesz has been much modified by post palaeozoic tectonism deep seismic reflection data where available show that the oceanic sutures are frequently associated with inclined reflectivity zones irz in the lithospheric mantle here inferred to mark relict subduction zones interpreting the age of subduction is complicated by offset of originally coplanar mantle and crustal segments of the irz resulting from early orogenic lithospheric delamination at the moho interface and or post orogenic reordering processes the mantle irz appear to indicate a n directed polarity for early palaeozoic subduction apparently incompatible with the geological evidence which indicates subduction of the tornquist sea beneath avalonia and a large amount of underthrusting of avalonia by baltica possible explanations for these apparently incompatible observations are evaluated

pollen record and integrated high resolution chronology of the early pliocene dacic basin southwestern romania an integrated stratigraphic study has been performed on four early pliocene fssections in the western dacic basin including the long reference section of lupoaia based on the integration of mediterranean nannoplankton assemblages the regional lignite stratigraphy records of large and small mammals large climatic fluctuations according to pollen grains and climatostratigraphic relationships at the european scale it has been possible to establish a magnetostratigraphic correlation of the different sections to the geomagnetic polarity time scale gpts this correlation suggests that all normal episodes of the early pliocene from thvera to cochiti chrons are recorded hence the complete pollen record covers an almost continuous time span from about 5 33 to 4 30 ma in addition the regional dacian romanian stage boundary in the dacic basin is located in the nunivak c3n 3n episode with an age of 4 55 0 05 ma our chronologic calibration combined with high resolution pollen data results in a detailed record of paleoclimate in which the 100 kyrs and 400 kyrs eccentricity cycles are clearly identified

kinematic evolution of the romanian carpathians abstract the regional pattern of contraction and extension directions and the evolution of the strain field from paleogene to neogene times enabled a reconstruction of the migration path of the carpathian collision front the carpathian nappes were thrust around the moesian plate during paleogene and early neogene times and protruded into a small oceanic embayment between the moesian and european plates the arc structure of the carpathian fold thrust belt was formed in late neogene times as a result of the eastward escaping tisza dacia block due to n directed convergence of the adriatic plate and the retreating subduction of an oceanic slab brittle deformation structures in the romanian carpathians suggest three tectonic events related to major plate motions 1 paleogene to middle miocene ne to ene contraction caused right lateral curved strike slip faults 2 middle miocene to pliocene fan shaped orientations of contraction directions were caused by right lateral oblique convergence in the southern carpathians frontal convergence in the southern eastern carpathians and left lateral convergence in the northern eastern carpathians 3 pleistocene to holocene general e w extension and n s contraction in the carpathian arc and local ese wnw contraction in the vrancea area is related to the late roll back stage and break off of the subducted slab in the bend area

messinian event in the black sea evidence of a messinian erosional surface in 1975 sediment cores from leg dsdp 42b sites 380a and 381 revealed a thin sediment layer in the black sea basin which points to a shallow water environment at the miocene pliocene boundary with these facts and in the wake of hypothesis of the messinian salinity crisis msc it was proposed that the black sea like the mediterranean sea suffered a desiccation period at the end of the messinian hsu k j and giovanoli f 1979 messinian event in the black sea palaeogeography palaeoclimatology palaeoecology 29 75 93 whereas the main topics of the msc in the mediterranean sea is now widely accepted the lack of evidence for a messinian erosional surface in the black sea left the debate about the messinian desiccation of this basin open until today the analysis of high resolution multi channel seismic data acquired during the blason surveys brings important new elements for this scientific debate 1 down the slope offshore the bosporus we show a clear erosional surface correlated to the top of the upper miocene shallow water environment unit of site dsdp 381 the overlying lower zanclean unit inevitably dates this erosional surface of the messinian event 2 a wide intra pontian erosional surface ipu is evidenced on the romanian shelf the ipu is characterized by a sharp decrease in the incision rate from outer deep canyons to inner shelf superficial incisions network according to the most recent paratethyan and mediterranean stratigraphic scale correlations the ipu erosional surface is considered as the analogue to the messinian erosional surface described down the slope offshore the bosporus in addition to recently discovered inland erosional signature the wide regional erosional surface we underline on the western black sea margins validates the black sea messinian desiccation hypothesis we also demonstrate that evaporative draw down of the black sea implied the installation in the basin of a negative hydrologic budget during the messinian the lack of a major messinian danube canyon on the romanian shelf supports the hypothesis of a messinian danube trapped in the dacic basin however the presence of a messinian superficial incision network connecting the location of the modern danube delta to deeply incised messinian canyons on the outer shelf ipu makes the hypothesis of a danube reaching the partially desiccated black sea still possible

the tectono stratigraphic evolution of distal hyper extended magma poor conjugate rifted margins examples from the alpine tethys and newfoundland iberia abstract in order to capture the general tectono stratigraphic framework of a magma poor conjugate rifted margin two examples have been analysed and compared the seismically imaged and drilled iberia newfoundland rifted margins e g seismic sections screech1 ise1 and the fossil distal tethys rifted margins exposed in the alps the lower austroalpine and the ligurian brianconnais units exposed in se switzerland and nw italy respectively are here considered and described for the first time as conjugate margins they form like the iberia newfoundland rifted margins conjugate upper and lower plate margin both pairs of margins show a similar first order morpho tectonic arrangement using the top of pre rift succession tprs and the base of post rift successions bprs as stratigraphic marker levels and two syn tectonic sequences sts 1 2 three major rift domains can be identified which experienced different evolutions and preserved different stratigraphic architectures i the proximal margin soled by normal 30 5 km thick continental crust it is characterized by widespread fault bounded graben half graben basins filled by the sts 1 showing growth structures followed by a succession time equivalent unit to sts 2 that does not show any evidence for syn depositional tectonic activity ii the upper plate distal margin floored by thinned to ultra thinned continental crust it can be subdivided into a distal high and a distal low separated by a major fault system the high is characterized by the occurrence of a marked syn rift unconformity leading to the erosion and or non deposition of the whole syn tectonic sequence sts 1 sts 2 the low displays complete stratigraphic successions in which the sts 2 becomes very characteristic and exclusive of this part of the margin iii the lower plate distal margin floored by hyper extended crust exhumed crust and subcontinental mantle the pre tectonic sequence and the sts 1 are only present inside extensional allochthons that are excised from the upper plate and passively transported on top of major exhumation faults the sts 2 deposited during the formation of the most distal domain is mostly formed by clasts derived from the dismantling of the extensional allochthons and of the surrounding exhumed basement it is overlain by deep marine turbidites and hemi pelagic sediments the nature of basement serpentinized mantle and hydrated upper or lower continental crust will selectively condition the composition of the sts 2 in the distal lower plate margin the recognition of a complex rift stratigraphy in the two conjugate pairs of margins shows that simple stratigraphic models are unable to describe the complete evolution of rifted margins from their initial stage preserved in the proximal margins to the final evolution leading to upper and lower plate margins in the conjugate distal margins this paper describes for the first time the stratigraphic relationships at distal conjugate rifted margins which is a key to understand the rift evolution and architecture of these yet little investigated systems

pliocene and lower pleistocene vegetation and climate changes at the european scale long pollen records and climatostratigraphy the biostratigraphically calibrated long pollen record at dsdp site 380 southwestern black sea displays a high resolution continuous and contrasted evolution of the vegetation in the region for the entire pliocene and lower pleistocene an accurate correlation is established with the reference global oxygen isotopic curve and with the northwestern european climatostratigraphy climatostratigraphic relationships are evident at the latitudinal and longitudinal scale of europe confirming the extensive strength of pollen analysis as a tool for correlations over large distances

benchmark data of a changing sea palaeogeography palaeobiogeography and events in the central paratethys during the miocene abstract the reconstruction and interpretation of terrestrial ecosystems and vegetational patterns in the central european miocene have to take into account the influence of a vast landlocked water body namely the paratethys sea as a northern appendage of the early mediterranean sea it spanned a north south gradient of at least 4 latitude and has been suggested to represent some kind of palaeothermometer which reflected slight expansions or restrictions of climatic belts due to its vulnerable marine connections it was also highly susceptible to major global sea level fluctuations which are reflected in phases of endemism hence a fairly continuous record of marine nearshore assemblages throughout the miocene reflects an extraordinary interplay of sea level fluctuations changes in climate immigrations and blooms in autochthonous elements whilst biostratigraphic implications of these patterns were recognised early in palaeontology a biogeographic model is still lacking the intermingling of palaeogeographic terms with those restricted to biogeography is still commonly used a situation which can be overcome by integrating data from different biota into a new palaeobiogeographic scheme herein a data set of 1809 species level taxa gastropoda and foraminifera serves as the base for interpretations gastropods in particular turned out to be of greatest value for the differentiation of palaeobiogeographic units due to sensitive reactions to all environmental parameters and occupying a wide range of ecological niches based on the excellent gastropod record the proto danubian province early danubian p danubian p balatonian p and a proto caspian subprovince are defined the biogeographic reorganisations are associated with five major biotic events within the gastropod faunas these big five comprise four extinctions the late ottnangian extinction event loee the mid badenian extinction event mbee the badenian sarmatian extinction event bsee the sarmatian pannonian extinction event spee and one exceptional immigration origination event termed the early badenian build up event ebbe foraminifera are less valuable for palaeobiogeographic purposes in the area and time slice studied endemisms are generally lower and turn over rates less dramatic they are however very useful for stratigraphic correlations with the mediterranean and atlantic areas this fairly well calibrated marine biostratigraphy of the central paratethys serves as stratigraphic backbone and control for continental stratigraphy

new evidence and model on the evolution of the southeast anatolian orogen this paper describes the orogenic evolution of the southeast anatolian orogenic belt based mostly on new geologic data collected from its constituent tectonic units in the course of new mapping programs of the past decade the southeast anatolian orogenic segment of the alpides may be divided into three approximately east west trending zones from south to north they are the arabian platform followed by a zone of imbrication and then a zone of nappes the arabian platform includes a mostly marine sedimentary succession deposited from early cambrian to middle miocene time the zone of imbrication is a narrow belt sandwiched between the arabian platform and the zone of nappes it consists of imbricated thrust slices emplaced onto a late cretaceous to early miocene sequence the zone of nappes is the highest tectonic unit consisting of two stacks of nappes simply designated the lower and upper nappes the lower nappe is represented by the slices of a polyphase metamorpbic ophiolitic assemblage and the maden group the upper nappe rests on the lower nappe and is represented by the bitlis and poturge metamorphic massifs southeastern anatolia underwent two major episodes of alpide deformation the first occurred during the late cretaceous period when ophiolite was emplaced on the arabian platform this event was not the consequence of a continental collision the ophiolite obduction onto the arabian platform was followed by a regionwide extension and a new marine transgression over the platform immediately after the ophiolite obduction the second episode of deformation occurred during middle eocene miocene time in two distinct stages as a result of the progressive elimination and complete closure of the ocean s which led to the collision between the zone of nappes located to the north being a part of eurasia and the arabian plate the maden marginal basin formed north of the subduction zone that eliminated the ocean between eurasia and arabia along the southern margin of the taurus belt and abutted the arabian plate much later during the final collision the second episode of deformation formed the present orogenic segment leading to the amalgamation of different tectonic units these amalgamated nappes collided with the arabian plate and welded onto it at the latest stage of the orogenic evolution during the miocene epoch

tectonomagmatic evolution of the final stages of rifting along the deep conjugate australian antarctic magma poor rifted margins constraints from seismic observations the processes related to hyperextension exhumed mantle domains lithospheric breakup and formation of first unequivocal oceanic crust at magma poor rifted margins are yet poorly understood in this paper we try to bring new constraints and new ideas about these latest deformation stages by studying the most distal australian antarctic rifted margins we propose a new interpretation linking the sedimentary architectures to the nature and type of basement units including hyperextended crust exhumed mantle embryonic and steady state oceanic crusts one major implication of our study is that terms like prerift synrift and postrift cannot be used in such polyphase settings which also invalidates the concept of breakup unconformity integration and correlation of all available data particular seismic and potential field data allows us to propose a new model to explain the evolution of magma poor distal rifted margins involving multiple and complex detachment systems we propose that lithospheric breakup occurs after a phase of proto oceanic crust formation associated with a substantial magma supply first steady state oceanic crust may therefore not have been emplaced before 53 3 ma corresponding to magnetic anomaly c24 observations of magma amount and its distribution along the margins highlight a close magma fault relationship during the development of these margins

stratigraphic and structural characteristics of the romanian black sea shelf abstract the western black sea basin opened during cretaceous times by back arc rifting in association with a north dipping subduction at the rear of the cretaceous early tertiary pontide volcanic arc the sedimentary wedge developed on the shelf of the romanian black sea sector reflects a complex interplay between large scale rifting uplift of the orogenic flanks large scale post rift subsidence and sea level changes we examine the detailed structural configuration of this sector for a regional correlation with the adjacent offshore in ukraine and bulgaria the evolution of the western black sea basin started in the albian cenomanian times when two extensional phases with significantly different directions n s and subsequently e w lead to the formation of a complex interplay between isolated blocks organised in horsts and grabens generally deepening eastwards superposition of normal faults footwall blocks from the two extensional episodes generated a deeply subsided area with enhanced accommodation space i e the histria depression and consequently recorded a larger thickness of paleogene sediments in the post rift stage re activation of faults and associated folding reflects repeated inversion during the late cretaceous oligocene times associated with subsequent periods of non deposition and or erosion during moments of basin fill exposure these periods of inversion recorded in the black sea are controlled by coeval orogenic deformations taking place in the balkans pontides and the crimean thrust belt sea level fluctuations during the neogene and late alpine tectonics in the neighbouring orogens caused massive sedimentation followed by sediment starvation and or significant erosion large thicknesses of sediments accumulated during the pontian presumably associated with an extensional episode deepening the distal parts of the basin and with differential compaction structures the interpretation of a high quality seismic dataset combined with published data allowed the correlation of major structural units and lineaments defined onshore towards the carpathians with the ones deeply buried below the western black sea basin sediments unit correlations are furthermore used to derive an integrated tectonic image of the western black sea area

recurrent phases of drought in the upper miocene of the black sea region abstract since the miocene the black sea proved to be highly sensitive to fluctuations in the hydrological cycle because of its recurrent restricted connections with the open ocean and the location between the dry mediterranean and more humid higher northern latitudes although the black sea formed one of the foci of the 1975 deep sea drilling project leg 42b robust tools to reconstruct past changes in its hydrological cycle were lacking at that time here we revisit the sedimentary succession hole 380a and determined compound specific carbon 13c hydrogen isotope ratios d of terrestrial and aquatic biomarkers to investigate changes in the hydrological budget of the black sea during the late miocene the 13c and d isotopic composition of n alkanes as well as alkenones and palynology indicate large environmental changes in the black sea and or in the sources of the water entering the black sea during the late miocene the d of alkenones showing an enrichment of more than 80 at the end of the miocene implies a major shift in basin hydrology possibly resulting in severely increased salinity these changes in d composition of the alkenones coincide with both with sharp shifts in reconstructed sea surface temperature and palynological assemblages two intervals with negative water budget were identified most likely caused by enhanced evaporation the older and longer dry evaporative phase predates the maeotian pontian boundary regional stages at 6 1 ma the younger drying phase corresponds to the messinian salinity crisis this shift to highly evaporative conditions is related to a similar shift previously observed in a messinian pontian sedimentary succession from the taman peninsula russia these recurrent dry phases likely reflect regional climatic shifts over a significantly larger area around the black sea area during the upper miocene

geodynamics of dobrogea romania new constraints on the evolution of the tornquist teisseyre line the black sea and the carpathians abstract dobrogea is the only place south of poland where the tornquist teisseyre line europe s longest lineament outcrops to characterize and date the tectonic activity of this line and to understand its relations with the neighboring structures e g the carpathians and the black sea basin the fracturing of late jurassic to neogene rocks in north central and south dobrogea is analyzed these paleostress reconstructions indicate that the dobrogea orogen was built under a n s compression with strain partitioning between thrusting at its front and dextral reverse slip along the peceneaga camena and capidava ovidiu faults during the late jurassic barremian from aptian to coniacian the dobrogea platform was characterized by se directed extension compatible with the aptian cenomanian rifting of the western black sea followed by the se directed drifting of a part of the moesian block i e the istanbul block on its southern extremity the tornquist teisseyre line does not show evidence for any large scale alpine strike slip movements postulated by many the peceneaga camena fault being reactivated in latest cretaceous paleogene as a pure reverse fault during the late tertiary the carpathian compression was poorly transmitted to dobrogea extension dominated the neogene deformation which indicates a weak coupling between the carpathians and its foreland

erosional processes and paleo environmental changes in the western gulf of lions sw france during the messinian salinity crisis abstract current interpretation of the messinian salinity crisis msc involves partial desiccation of the mediterranean sea coupled with the deposition of thick evaporites in the deep basins new sets of seismic reflection profiles in the western part of the gulf of lions confirm the basinward extension of the messinian erosion and enable the mapping of distinctive seismic markers indicating the messinian erosional surface or messinian unconformity the basin margin detrital deposits and the deep evaporite sequence the geometrical relationship between these three elements and their relationship to the paleogeography of the margin during the msc provide new information about the evolution of the study area during the messinian the messinian erosional surface mes commonly correlated with the desiccation phase and the deposition of deep evaporites during the apogee of the event is generally interpreted as a subaerial feature in the gulf of lions it is a complex diachronic polygenic erosional surface observed at the base of the prograding plio quaternary sequence beneath the shelf and slope it extends downslope beneath the deep basin upper evaporites and the salt and possibly correlates conformably with the base of the so called deep lower evaporites the whole morphology of the mes reflects a buried drainage pattern supporting the interpretation of fluvial erosion driven by a substantial drop in sea level our results also suggest that large submarine gravity flows occurred prior to any significant accumulation of salt in the basin and prior to the upper evaporites consequently interbedded clastic deposits may partly account for the parallel reflectors of the lower evaporites since river erosion persisted throughout the msc the salt and upper evaporite units may also contain a large amount of detrital sediments the good quality of the new seismic data clearly reveals fan shaped messinian deposits in the downstream part of the main messinian valleys i e the nile var and spanish rivers the depositional scenarios generally involve a substantial sea level fall coupled with deltaic prodeltaic accumulations a chaotic seismic unit unit d filling messinian lows and extending beneath the salt within the study area is interpreted as a messinian clastic unit we propose a polyphase scenario of detrital fan deposition involving pre syn and post salt deposition in subaqueous subaerial environments in the gulf of lions a late miocene tectonic phase that affected the western shelf also played an important role in controlling a the pattern of the messinian fluvial network b the location of maximum erosion on the shelf and c the location of the detrital fan depocentre downslope

late miocene and early pliocene environments in the southwestern black sea region from high resolution palynology of dsdp site 380a leg 42b a high resolution palynological study has been performed on late miocene messinian and early pliocene zanclean sediments cored at dsdp site 380a leg 42b a late miocene coastal vegetation has been identified in association with a delta environment the pliocene is characterised by competition between the two most important vegetation components namely humid thermophilous forests and dry steppes with changes driven by large amplitude climatic variations these variations are linked to other european reference pollen records and to the global temperature evolution for the early pliocene and result in climatostratigraphic relationships at large geographic scale an orbital tuning is proposed with respect to new data clarifying time control on the section the black sea appears to have dried up in response to the messinian salinity crisis in the mediterranean with which it might have been connected during periods of high sea level

the geological history of the istria depression romanian black sea shelf tectonic controls on second third order sequence architecture the istria depression or sub basin of offshore romania lies at the intersection of the trans european tornquist teisseyre zone and the black sea back arc basin just outboard of the east carpathian orogenic welt its late mesozoic cenozoic succession records an extraordinary cpolyphase history of subsidence and sedimentation interrupted by several quite spectacular 2nd 3rd order erosional unconformities reflecting the interplay between these teetonic domains the unconformities divide the succession into a number of stratigraphic sequences the sub basin first developed as a transtensional rift in the triassic early jurassic evolving into a narrow oceanized trough in later jurassic this was tilted west during the early cretaceous by uplift and rifting in the western black sea and the residual late jurassic topography was filled and buried by a west facing clastic evaporite wedge late aptian albian post rift subsidence and spreading in the western black sea imposed a strong easterly tilt encouraging the partial evacuation of its early cretaceous sedimentary fill by gravity driven mass wastage the incised valley topography was subsequently buried in the later cretaceous and early cenozoic during the mid late cenozoic the black sea basin experienced intermittent periods of partial to complete isolation from the world ocean and significant base level drawdown the first major sea level fall occurred in the eocene when the istria depression was deeply incised to be healed by oligocene shales during the subsequent rise yet another period of drawdown and exposure occurred in mid miocene with extensive shelf margin mass wastage and erosion followed by reflooding and deposition of a transgressive backstepping sequence in mid late miocene messinian drawdown in the mediterranean caused a further period of isolation and falling base level the shelf margin was again exposed and experienced widespread mass wastage and slumping a marine connection was re established in late messinian rising sea level eroded the earlier slumped sequence and the margin was healed by a lowstand prograding wedge in late miocene early pliocene this was followed by shelf sedimentation in the plio pleistocene periodically interrupted by canyon incision events testifying to continued climatically or tectonically imposed base level fluctuations several direct and indirect tectonic factors were responsible for valley canyon incision within the istria depression and erosion of the romanian black sea shelf margin these include 1 the local structural framework 2 direct tectonic uplift and tilting and 3 more indirect tectonically imposed isolation encouraging significant base level falls

a mechanism to thin the continental lithosphere at magma poor margins crustal thinning where continental plates break apart can be accomplished by a system of conjugate concave downward faults instead of multiple normal faults through exhumation of mid crustal and mantle material where continental plates break apart slip along multiple normal faults provides the required space for the earth s crust to thin and subside1 after initial rifting however the displacement on normal faults observed at the sea floor seems not to match the inferred extension2 here we show that crustal thinning can be accomplished in such extensional environments by a system of conjugate concave downward faults instead of multiple normal faults our model predicts that these concave faults accumulate large amounts of extension and form a very thin crust 10 km by exhumation of mid crustal and mantle material this transitional crust is capped by sub horizontal detachment surfaces over distances exceeding 100 km with little visible deformation our rift model is based on numerical experiments constrained by geological and geophysical observations from the alpine tethys and iberia newfoundland margins3 4 5 6 7 8 9 furthermore we suggest that the observed transition from broadly distributed and symmetric extension to localized and asymmetric rifting is directly controlled by the existence of a strong gabbroic lower crust the presence of such lower crustal gabbros is well constrained for the alpine tethys system4 9 initial decoupling of upper crustal deformation from lower crustal and mantle deformation by progressive weakening of the middle crust is an essential requirement to reproduce the observed rift evolution this is achieved in our models by the formation of weak ductile shear zones

the black sea back arc basin insights to its origin from geodynamic models of modern analogues the black sea is generally thought to be a back arc basin with active extension rifting beginning in late early cretaceous times although some fundamental issues such as the presence or absence of a related magmatic arc and the orientation of the related driving subduction zone remain vaguely defined at best however as shown here the regional structure of the black sea is consistent with that predicted by geodynamic models of modern back arc basin formation in which extension is driven by slab roll back this includes an asymmetric distribution of horst and graben structures in the back arc basin the distribution and spacing of which is related to the strength of the underlying lithosphere which forms the hanging wall of the subduction zone by analogy the intrabasinal structure of the black sea as a whole is explicable as the consequence of a single phase of asymmetric back arc basin formation not two separate phases independently responsible for its western and eastern segments and its underlying lithosphere is rheologically strong as predicted by recent models of precambrian europe and present day tomography

rise and fall of the paratethys sea during the messinian salinity crisis abstract extremely thick evaporite units were deposited during the so called messinian salinity crisis msc 5 96 5 33 ma in a deep mediterranean basin that was progressively disconnected from the atlantic ocean a crucial but still poorly understood component in messinian evaporite models is the connectivity between mediterranean and paratethys i e the former black sea domain inadequate stratigraphic correlations and insufficient age control for paratethys sediments have so far hampered a thorough understanding of hydrological fluxes and paleoenvironmental changes here we present a new chronology for the eastern paratethys by integrating biostratigraphic and paleomagnetic data from mio pliocene sedimentary successions of romania and russia we show that a major flooding event from the mediterranean surged the paratethys basins at the maeotian pontian boundary 6 04 million years ago this indicates that sea level in both mediterranean and paratethys was high at the beginning of the msc we argue in favor of changes in paratethys mediterranean connectivity to initiate the msc in combination with elusive tectonic processes in the gibraltar arc a subsequent fall of paratethyan water level closely coincides to the mediterranean isolation event corresponding in age to the glacial cycles tg12 14 5 60 5 50 myr in the latest messinian a major climate change towards more humid conditions produced a positive hydrological balance and likely a transgression in the paratethys although our stratigraphic resolution cannot exclude a possible relation to the pliocene flooding of the mediterranean here

is the impact of the messinian salinity crisis in the black sea comparable to that of the mediterranean abstract erosional features have been observed along the black sea shelf in wells and on seismic reflection profiles that are broadly similar to the seismic stratigraphic signature of the messinian salinity crisis msc in the mediterranean in particular the intra or middle pontian unconformity has been suggested by some as the manifestation of the msc in the black sea basin missing strata and prominent lithological changes associated with the inferred msc unconformity indicate erosional removal of parts of the underlying cenozoic deposits in the shelf areas of the entire black sea the magnitude of the relative sea level drop associated with this unconformity has been much debated and ranges from tens of meters to thousands of meters the suggestion of a very large 1600 m sea level drop in the black sea during the msc is primarily based on the findings of shallow water clastics and carbonates in deep sea drilling project dsdp wells 380 and 381 however recently acquired long offset seismic data clearly show that both of these wells penetrated gravity driven mega slumps and mass transport complexes therefore the interpreted shallow water msc units in these deepwater wells do not represent in situ rock formations but rather allochthonous strata derived from the basin margin moreover compared to the typical seismic expression of the msc in the mediterranean detailed interpretation of 2d 3d seismic data sets in the bulgarian and turkish black sea revealed considerably more complexity this marked difference is tentatively attributed to the extent of erosion associated with the msc in the black sea i e the multiple msc incisions occurred in a submarine setting not on a subaerially exposed palaeoslope therefore the magnitude of the sea level drop and the overall impact of the msc in the black sea appear to be significantly less than in the mediterranean

paleoceanography and climate of the badenian middle miocene 16 4 13 0 ma in the central paratethys based on foraminifera and stable isotope δ 18 o and δ 13 c evidence benthic foraminifera and stable isotopes analyses revealed changes emerging in the paleoceanographic scenery in the paratethys the percentage of inbenthic oxyphylic taxa and diversity in the benthic foraminiferal assemblage showed increasing food supply organic matter decreasing oxygen level and growing stress on the sea floor oxygen isotopes measured in planktonic and benthic foraminifera pointed to strengthening stratification during the badenian period the carbon isotopes indicated intensified accumulation of light marine organic matter this increasing stratification trend is especially pronounced by late badenian 13 5 13 ma when surface water oxygen isotope values are rather negative a simple two layer circulation model was worked out for the badenian paratethys explaining these characteristic environmental changes an antiestuarine lagoonal circulation is assumed for the central paratethys during the early 16 4 15 ma and mid badenian 15 13 5 ma the mid badenian period of time comprises the short episode of evaporite formation in the carpathian foredeep and the transylvanian basin evidence presented here supported a reversal of circulation to estuarine type after the deposition of salts by late badenian 13 5 13 ma the early badenian antiestuarine circulation is suggested to associate with the high temperatures of the mid miocene climatic optimum and the late badenian estuarine circulation with the cooler period following it

constraints on arabian plate motion and extensional history of the red sea analysis of the geologic and geophysical data from the western and northern margin of the arabian plate combined with data from the red sea gulf of aden leads to an interpretation of arabian plate motion that supports an episodic extensional history in the red sea and gulf of aden phase 1 extension began in medial to late eocene and was caused by the nw propagation of the reoriented central indian ridge spreading center it stretched and thinned continental crust along numerous wrench and normal faults that reactivated preexisting structures first phase extension stopped when the arabian plate terminally sutured to eurasia in the medial miocene and halted northward movement of arabia relative to africa the combined african arabian plates moved north more slowly constricting and thickening continental crust in the bitlis zagros sutures while the red sea remained technically quiescent and accumulated salt by the early pliocene continued northward movement was accommodated by lateral extrusion of large continental wedges north of the bitlis zagros sutures this allowed arabia to move northward faster than africa and reopen the red sea where phase 2 extension was expressed by seafloor spreading extension within the red sea gulf of aden rift system has been controlled by the interactions and effects of two factors 1 convergent processes between the north margin of the arabian plate and the eurasian plate to the north and 2 northwest propagation of extension associated with the medial eocene reorganization of the central indian spreading center

symmetry vs asymmetry of a hyper thinned rift example of the mauleon basin western pyrenees france abstract the aim of this study is to unravel the tectono sedimentary evolution of a hyper thinned rift based on the example of the mauleon basin a basin filled by thick synrift deposits the integrated study combines field data detailed geological mapping and seismic interpretation the field study focuses on the iberian margin of the mauleon basin seismic interpretation and well calibration along a n s transect of the mauleon basin enable imaging the transition with the northern conjugate margin the synrift records are very different on either side of the basin the southern margin is composed of a proximal turbiditic s l siliciclastic system whereas the northern margin is characterized by a carbonate system extending from the platform to the basin we recognize the mauleon rift as an apparent symmetric hyper thinned rift related to a southward dipping albian detachment and a northward dipping cenomanian one two stages of continental crustal thinning are inferred to explain the development of the mauleon basin first a barremian to earliest albian ductile pure shear thinning phase responsible for the lower crustal thinning and the formation of a symmetric sag basin second an albian cenomanian simple shear thinning phase responsible for the onset of the southward dipping saint palais detachment faulting and for evolution to an asymmetric basin the iberian margin appears as an upper plate and the european one as a lower plate during albian time at early cenomanian time the basin was affected by structural changes of the margins resulting from shift in detachment direction interpreted as flip flop detachment tectonics

late miocene to early pliocene chronostratigraphic framework for the dacic basin romania abstract new magnetostratigraphic results and calcareous nannofossil data of seven sections in the dacic basin of southern romania covering the latest maeotian to early romanian time span 6 4 4 0 ma allow a correlation with the current astronomical polarity time scale this establishes a chronological framework for the pontian and dacian stages of the paratethys and facilitates to correlate the paratethys stages with those of the mediterranean the maeotian pontian boundary is estimated at 6 15 0 11 ma within subchron c3an 1n while the age of the pontian dacian boundary is 5 30 0 1 ma within subchron c3r the odessian portaferrian and portaferrian bosphorian substage boundaries can be placed at about 6 0 and 5 6 ma at the base and near the end of chron c3r respectively consequently the pontian stage has a duration of approximately 0 85 myr and is coeval with the upper half of the messinian stage the base of the dacian stage corresponds to the onset of the pliocene and is coeval with the pontian kimmerian boundary of the euxinic black sea basin the dacian romanian boundary is recorded either at 4 58 0 05 ma in subchron c3n 2n nunivak or at 4 25 0 05 ma in subchron c3n 1n cochiti the length of the dacian stage is therefore about 0 7 myr or approximately 1 ma the transition of the getian into the parscovian substage can be dated at 4 83 ma within subchron c3n 3n sidufjall or at 4 55 ma within subchron c3n 2n nunivak the occurrence of calcareous nannofossil assemblages in the lower portaferrian and near the portaferrian bosphorian transition belonging to the upper part of the discoaster quinqueramus nn11 zone and in the middle bosphorian belonging to the amaurolithus tricorniculatus nn12 zone indicates the presence of ephemeral marine connections between the paratethys basin and the mediterranean during the late messinian another marine influx inferred from nannofossil species characteristic of the nn12 zone and found in lower dacian sediments near the top of subchron c3n 4n thvera post dates the basal pliocene transgression of the mediterranean basin

marine gateway vs fluvial stream within the balkans from 6 to 5 ma since the discovery of calcareous nannofossils dinoflagellate cysts and planktonic foraminifers in deposits from the dacic basin intensive research has been performed in order to evidence which gateway this microplankton used to connect paratethys and the mediterranean prior and after the messinian salinity crisis msc such a gateway is also to be regarded at the origin of successive influxes of paratethyan organisms molluscs ostracods dinoflagellates into the mediterranean basin lago mare events observing that the i stanbul area usually proposed for this purpose was inefficient we examine the succession of marine well dated pre msc and post msc deltaic deposits through the balkans from northern greece to southern romania that constitutes a reliable candidate for such a marine corridor the origin of which was caused by the regional tectonic extension the reconstructed palaeogeography for high sea level episodes that encompassed the msc clarifies the context of the so called north aegean lake this marine gateway probably evolved as a powerful river during the peak of the msc contributing to the deposition of clastics in the hydrocarbon prinos field a tectonically controlled subsidence to the north and south of the skopje region caused the closure of such a gateway

alternate interpretation of the messinian salinity crisis controversy resolved a high resolution chronology of the mediterranean messinian salinity crisis is proposed two types of evaporite deposition may be distinguished those in marginal areas vs those in basinal ones their diachroneity is deduced from the stratigraphic relationships linking these evaporites to a major messinian erosional surface a two step model is proposed for the evolution of the salinity crisis through time during the first phase from 5 75 to 5 60 ma the deposition of marginal evaporites took place in response to a modest sea level fall in the second interval from 5 60 to 5 32 ma the mediterranean basin became isolated during this later period the deposition of basinal evaporites and the cutting of the mediterranean canyons took place

paleomagnetic structural and stratigraphic constraints on transverse fault kinematics during basin inversion the pamplona fault pyrenees north spain 1 the pamplona fault in the pyrenees is a major transverse structure that has been classically interpreted as a strike slip fault however lack of consensus concerning the sense of movement casts doubt on its actual kinematics and as a consequence its role in the cenozoic evolution of the pyrenees remains controversial in order to assess its kinematics we have conducted a paleomagnetic structural and stratigraphic study focused on the mesozoic and tertiary sedimentary rocks that outcrop around the southern segment of the fault restoration of balanced cross sections allows us to examine the present day spatial relationship of the sedimentary sequences on both sides of the fault and to reconstruct the geometry of the extensional basins formed during mesozoic rifting episodes in the bay of biscay and pyrenean domains paleomagnetic results indicate that no significant tectonic rotations occurred around the fault during tertiary inversion of the pyrenees the lack of tectonic rotations and revaluation of previous hypotheses argues against a strike slip movement of the fault we propose a new model in which the pamplona fault is treated as a large scale hanging wall drop fault whose kinematics was determined by variations in the geometry and thickness of mesozoic sequences on both sides of the fault these variations influenced the geometry of the thrust sheet developed during tertiary compression we are unaware of any other transverse fault that has been interpreted in this fashion thus the pamplona fault serves as a case study for the evolution of transverse faults involved in basin inversion processes

tectonic evolution of the intra pontide suture zone in the armutlu peninsula nw turkey abstract the armutlu peninsula and adjacent areas in nw turkey play a critical role in tectonic reconstructions of the southern margin of eurasia in nw turkey this region includes an inferred intra pontide oceanic basin that rifted from eurasia in early mesozoic time and closed by late cretaceous time the armutlu peninsula is divisible into two metamorphic units the first the armutlu metamorphics comprises a precambrian high grade metamorphic basement unconformably overlain by a palaeozoic low grade mixed siliciclastic carbonate volcanogenic succession including bimodal volcanics of inferred extensional origin with a possibly inherited subduction signature the second unit the low grade iznik metamorphics is interpreted as a triassic rift infilled with terrigenous calcareous and volcanogenic lithologies including basalts of within plate type the triassic rift was unconformably overlain by a subsiding jurassic late cretaceous cenomanian passive margin including siliciclastic carbonate turbidites radiolarian cherts and manganese deposits the margin later collapsed to form a flexural foredeep associated with the emplacement of ophiolitic rocks in turonian time geochemical evidence from meta basalt blocks within ophiolite derived melange suggests a supra subduction zone origin for the ophiolite the above major tectonic units of the armutlu peninsula were sealed by a maastrichtian unconformity comparative evidence comes from the separate almacik flake further east considering alternatives it is concluded that a mesozoic intra pontide oceanic basin separated eurasia from a sakarya microcontinent with a wider northern neotethys to the south lateral displacement of exotic terranes along the south eurasian continental margin probably also played a role e g during late cretaceous suturing in addition to overthrusting

magnetostratigraphy and radio isotope dating of upper miocene lower pliocene sedimentary successions of the black sea basin taman peninsula russia abstract we present a new chronology for the upper miocene to pliocene deposits of the black sea basin based on high resolution magnetostratigraphic data coupled with 40 ar 39 ar dating from the 475 m long zheleznyi rog section on the taman peninsula russia this section comprises the stratigraphic interval of the khersonian to kimmerian regional stages of the eastern paratethys our magnetostratigraphic record is based on biogenic and early diagenetic greigite components and yields a magnetostratigraphic sequence of 8 polarity zones a volcaniclastic ash layer at the upper part of the khersonian is radio isotopically dated at 8 69 0 18 ma the age of the khersonian meotian transition arrives at 8 6 or 8 2 ma which is significantly younger than earlier estimates the new age has important consequences for the hipparion datum in the eastern paratethys and implies that all vallesian fossil sites are younger than 11 2 ma the meotian stage has a total duration of 2 2 to maximum 2 6 myr and is marked by multiple erosional events the end of the paratethys sea is dated at 5 5 ma when the black sea becomes isolated from the caspian sea the dacian basin and the mediterranean

oligocene uplift of the western greater caucasus an effect of initial arabia eurasia collision the greater caucasus is europe s largest mountain belt significant uncertainties remain over the evolution of the range largely due to a lack of primary field data this work demonstrates that depositional systems within the oligocene early miocene maykop series on either side of the western greater caucasus wgc display a similar provenance and divergent palaeocurrents away from the range constraining a minimum age for the subaerial uplift of the range as early early oligocene an eocene oligocene hiatus basal oligocene olistostromes and a marked increase in nannofossil reworking also point to initial deformation in the earliest oligocene the initial uplift of the wgc occurred during the final assembly of the tethysides to its south uplift commenced after the late eocene final suturing of northern neotethys and during the initial collision of arabia with the southern accreted margin of eurasia this suggests that compressional deformation was rapidly transferred across the collision zone from the indenting arabian plate to its northern margin

tectonosedimentary evolution of the deep iberia newfoundland margins evidence for a complex breakup history most of the conceptual ideas concerning sedimentary architecture and tectonic evolution of deep rifted margins are based on either intracontinental rift basins or proximal margins both of which underwent only small amounts of crustal thinning in this paper we investigate the tectonosedimentary and morphotectonic evolution related to continental breakup of the highly extended deep iberia newfoundland margins our results show that continental breakup is a complex process distributed in time and space on the basis of mapping of dated seismic units and borehole data we are able to identify two major phases of extension during a first phase dated as tithonian to barremian 145 128 ma deformation is related to exhumation of mantle rocks basins become younger oceanward and fault geometry changes from upward to downward concave resulting in complex sedimentary structures and basin geometries a second phase dated as latest aptian 112 ma overprints previously exhumed mantle and accreted juvenile oceanic crust over more than 200 km leading to the formation of basement highs the observed complex breakup history challenges classical concepts of rifting and leads to new interpretations for the tectonosedimentary evolution of deep rifted margins

the region of the strandja sill north turkey and the messinian events the two sides of the strandja sill show a highly discontinuous stratigraphic succession since the late oligocene this area together with the sea of marmara basin is usually proposed as the gateway for the paratethyan freshwaters and organisms that constituted the lago mare facies in the mediterranean sea during the messinian salinity crisis msc our investigations involving new field observations and datings together with previous studies suggest that the sill has possibly experienced such a connection at around 8 ma i e significantly before the crisis the proposal of a sea level drop of the black sea before 7 ma is not supported by our data on dinoflagellate cysts consistency of calcareous nannofossil succession at dsdp site 380 is reinforced allowing to reassert that subaerial erosion impacted both the southwestern black sea and the central marmara dardanelles area during the peak of the msc at that time this region was crossed by two oppositely directed fluvial networks further supporting the absence of a marine gateway through the strandja sill it is concluded that none of the lago mare events recorded in the mediterranean during the msc were the consequence of the passage of paratethyan waters and organisms through this area in the black sea the well dated messinian fluvial erosion can be followed offshore the overlying prograding deltaic deposits attest to a fast marine reflooding after the crisis this constitutes a comprehensive erosion sedimentation model in an area intensively explored for hydrocarbons