aftsolve a program for multi kinetic modeling of apatite fission track data aftsolve is a computer program for deriving thermal history information from apatite fission track data it implements a new fission track annealing model that takes into account the known kinetic variability among different apatite species to fully utilize this model a fission track worker must obtain data that can be used to infer the kinetic characteristics of each apatite grain from which a measurement was taken such data can consist of etch figure lengths or chemical composition the benefit of this overall approach is that it allows useful information to be derived from previously unusable analyses extends the practical range of geological temperatures constrained by fission track analyses and increases overall confidence in model predictions aftsolve also incorporates the effects of fission track orientation relative to the apatite crystallographic c axis variation in initial track length and the biasing effect of 2 5 2 cf irradiation for enhancing confined horizontal track length detection aftsolve is written for windows operating systems and has a graphical interface that allows interactive input of thermal histories and real time generation of estimates for fission track length distributions and ages for up to six simultaneously modeled kinetic populations it also includes procedures for estimating the range of time temperature histories that are statistically consistent with a data set and constraints entered by the user

tectonic implications of paleomagnetic research into upper cretaceous magmatic rocks in the apuseni mountains romania the paleomagnetism of upper cretaceous magmatic rocks from 47 collecting sites 172 samples 692 specimens in the apuseni mountains was studied after af cleaning characteristic magnetizations were identified for various collecting areas in the study zone which defined a few spatial and temporal units for which paleomagnetic poles could be derived statistically at 21 sampling sites the paleomagnetic directions showed a high level of intrasite and intersite consistency with a mean direction of if 38 and df 100 with 95 6 the paleomagnetic results show that to reach their present day position the apuseni mountains moved to the north around 14 with respect to europe or around 25 with respect to the geographic poles between the campanian and probably late miocene while a clockwise rotation of around 80 was taking place

from nappe stacking to exhumation cretaceous tectonics in the apuseni mountains romania new ar ar muscovite and rb sr biotite age data in combination with structural analyses from the apuseni mountains provide new constraints on the timing and kinematics of deformation during the cretaceous time temperature paths from the structurally highest basement nappe of the apuseni mountains in combination with sedimentary data indicate exhumation and a position close to the surface after the late jurassic emplacement of the south apuseni ophiolites early cretaceous ar ar muscovite ages from structurally lower parts in the biharia nappe system dacia mega unit show cooling from medium grade conditions ne sw trending stretching lineation and associated kinematic indicators of this deformation phase d1 are overprinted by top nw directed thrusting during d2 an albian to turonian age 110 90 ma is proposed for the main deformation d2 that formed the present day geometry of the nappe stack and led to a pervasive retrograde greenschist facies overprint thermochronological and structural data from the bihor unit tisza mega unit allowed to establish e directed differential exhumation during early late cretaceous times d3 1 brittle detachment faulting d3 2 and the deposition of syn extensional sediments indicate general uplift and partial surface exposure during the late cretaceous brittle conditions persist during the latest cretaceous compressional overprint d4

toward understanding the post collisional evolution of an orogen influenced by convergence at adjacent plate margins late cretaceous tertiary thermotectonic history of the apuseni mountains 1 the relationship between syn to post collisional orogenic shortening and stresses transmitted from other neighboring plate boundaries is important for understanding the kinematics of mountain belts but has received little attention so far the apuseni mountains are an example of an orogen in the interference zone between two other subduction systems located in the external carpathians and dinarides this interference is demonstrated by the results of a combined thermochronological and structural field study that quantifies the post collisional latest cretaceous tertiary evolution the exhumation history derived from apatite fission track and u th he thermochronology indicates that the present day topography of the apuseni mountains originates mainly from latest cretaceous times modified by two tectonic pulses during the paleogene the latter are suggested by cooling ages clustering around 45 ma and 30 ma and the associated shortening recorded along deep seated fault systems paleogene exhumation pulses are similar in magnitude 3 5 km and are coeval with the final collisional phases recorded in the dinarides and with part of the carpathian rotation around the moesian promontory these newly quantified paleogene exhumation and shortening pulses contradict the general view of tectonic quiescence subsidence and overall sedimentation for this time interval the miocene collapse of the pannonian basin did not induce significant regional exhumation along the western apuseni flank nor did the subsequent carpathian collision this is surprising in the overall context of pannonian basin formation and its subsequent inversion in which the apuseni mountains were previously interpreted as being significantly uplifted in both deformation stages

alpine crustal shear zones and pre alpine basement terranes in the romanian carpathians and apuseni mountains the carpathian orocline formed by complex suturing of small continental fragments to the east european and moesian plate remnants of continental fragments belong to three pre alpine lithotectonic assemblages a greenstone granite association and two gneissic assem blages during alpine collision pieces of crust were repeatedly fragmented and welded to accommodate heterogeneous strain along the irregular east european plate boundary shallow structural levels of alpine tectonic discontinuities in which the locus of most intense strain migrated over time are now exposed as wide retrograde greenschist grade belts repeated mainly transpressive deformation resulted in early ductile fabrics being overprinted by local brittle shear strain igneous intrusion accompanied different phases of tectonic activity the age of shearing initiation is probably late paleozoic and the configuration of the zones and their alpine internal structures are consistent with the geometry of the carpathian arc

mesozoic evolution of the tisza mega unit the south eastern part of the basement of the pannonian basin is made up of variscan crystalline complexes and early mesozoic formations showing striking affinity with the corresponding formations in the southern margin of the european plate this large composite structural unit which is actually an exotic terrane of european plate origin has been named the tisza mega unit based upon relevant data of the pre tertiary basement of southern hungary the reconstruction of the position of the tisza terrane in the early alpine evolutionary stages the process of its separation and break off from the european plate and results of its eo alpine deformations are summarised in the present paper in the variscan and early alpine evolutionary stages the area of the later tisza mega unit was located at the margin of the european plate during variscan orogeny terrane accretion led to intensive deformation and metamorphism in this belt this was followed by transpressional tectonics and the development of molasse basins in the late and post variscan stages and passive margin evolution after the neotethys opening in the middle triassic the separation of the tisza mega unit began with incipient continental rifting along the axis of the later ligurian penninic vahic oceanic branch in the late triassic the end of terrigenous material deposition in the most external zones and a coeval change in fossil assemblage point to the separation of the tisza block from the european plate in the early bathonian significant rotation of the tisza mega unit and coeval paroxysm of alkaline rift type basalt volcanism took place in the early cretaceous in the mid cretaceous due to the northward motion of the adria block and the related closure of the westernmost neotethys basin the extensional regime changed to a compressional one leading to onset of the nappe stacking and low grade regional metamorphism within the tisza microplate in the foreland of the nappe systems flexural basins came into existence that are characterised by flysch type sedimentation in the early tertiary the north eastward motion of the alcapa and tisza dacia blocks led to the formation of the present day heterogeneous basement of the pannonian basin

coal facies studies in denmark and greenland abstract coal of jurassic age occurs onshore denmark and in the danish north sea whereas coal of carboniferous and miocene age only occurs in the danish north sea and onshore denmark respectively the lower middle jurassic coals are the most widespread and best documented onshore denmark the coals are of low rank while the jurassic coals in the north sea are thermally mature and hydrocarbon generating in the sogne basin the jurassic coals have a maximum thickness of 2 m and were formed in coastal plain mires and in inland fresh water mires the miocene brown coals up to 2 m thick were formed in an overall deltaic setting lower carboniferous and palaeogene coals occur in northern greenland middle jurassic coals in northeast greenland and cretaceous coals in western greenland the middle jurassic low rank coals have been investigated in detail the up to 3 5 m thick coal seams accumulated in coastal mires and they may have an extraordinary resinite enriched composition only a single cretaceous coal seam has been investigated with regard to the depositional environment the seam records drowning of a peat mire the lower carboniferous and palaeogene coals have not been investigated

the transylvanian basin romania and its relation to the carpathian fold and thrust belt insights in gravitational salt tectonics abstract interpretation of regional seismic profiles stratigraphic and sedimentologic data improved insights in the evolution of the transylvanian basin the basin evolution was coeval with the post mid cretaceous to recent deformation of the carpathian mts four tectonostratigraphic megasequences are differentiated upper cretaceous rift paleogene sag lower miocene flexural basin and middle to upper miocene backarc sequence dominated by gravitational tectonics the mid miocene continental collision in the eastern carpathians is associated with the rising carpathians this uplift enhanced the differential load which together with the high heat flow induced by late miocene to pliocene arc volcanism triggered large scale mio pliocene gravity spreading of the salt overburden this mega slide comprises three structural domains as follows extensional weld upslope contractional folds central and contractional toe thrust downslope the diapirs in the east indicate a pre shortening reactive passive growth stage the central folds are mostly the result of late shortening basement involved thrusting uplifted the toe thrust domain by the late pliocene the late neogene to recent carpathians uplift backarc volcanism and gravity spreading are largely coeval

neogene kinematics of the transylvanian basin romania the transylvanian basin is a major sedimentary basin located in the eastern part of the european alpine orogenic system it has a sedimentary fill more than 5 km up to 8 km in some small areas thick of upper cretaceous to upper miocene deposits it represents the main gas producing province in romania and central eastern europe in this article we analyze seismic lines and structural data from the basin as well as from its northern eastern and southeastern borders these data indicate a tectonic origin for the neogene structures from the transylvanian basin these structures include 1 northeast and southwest dipping thrust faults and 2 east northeast and west northwest striking strike slip faults having normal or reverse slip secondary structures such as salt diapirs and folds are related to these faults structural data from the basin and its border indicate a neogene overall compressional transpressional regime having maximum principal stress oriented north to northeast daniel ciulavu received a diploma in geology and geophysics at the university of bucharest in 1989 and his ph d in geology at the vrije universiteit amsterdam netherlands in 1999 he worked two years for geasol s a romania in hydrogeology coal and alluvial gold exploration since 1991 he has been on the staff of the university of bucharest where he teaches the courses on structural geology in the department of geophysics and kinematic analysis for master s students corneliu dinu received a diploma in geology in 1966 and his ph d in 1976 at the university of bucharest romania after graduation he worked as field geologist for prospectiuni s a romania since 1970 he has been on the staff of the university of bucharest where he is professor of structural geology and basin analysis since 1990 he has served as the dean of sciences at the faculty of geology and geophysics university of bucharest alexandru szakacs received a diploma in geology in 1974 and his ph d in 2000 at the university of bucharest romania he is senior geologist at the romanian institute of geology he has 25 years of experience in studying the neogene volcanism of the carpathian pannonian area he has also worked on the neogene volcanism of the cordillera betica spain dorin dordea received a diploma in geology in 1974 at the university of cluj romania his field of activity is remote sensing he has worked in several areas in africa and romania since 1999 he has served as the chief geologist of prospectiuni s a bucharest romania he is now working on the application of remote sensing in mining exploration

apatite fission track analysis of oligocene strata in south texas u s a testing annealing models analysis of apatite fission track data from forty seven surface and subsurface samples of fine grained sandstone to pebbly conglomerate from the oligocene catahoula gueydan frio and vicksburg formations documents the response of fission track ages and track length distributions to simple post depositional thermal histories characterized by monotonic heating data from outcrop samples document that the apatite component was derived from source areas characterized by rapid cooling through the temperature range from 120 to 50 c during the early tertiary the apatite population is characterized by a log normal chlorine distribution mean 0 3 wt 0 3 wt consisting predominantly of low cl apatites 80 is 0 5 wt mean track lengths from core samples decrease systematically with increasing depth and temperature the decrease in apatite fission track ages with increasing depth and temperature is less systematic due to the scatter in inherited ages at the time of deposition no tracks were observed in apatite from samples at temperatures above 130 c mean track lengths for the south texas data agree well with those for a similar data set from the otway basin southeastern australia for present day temperatures of 70 c at higher temperatures mean lengths are 1 to 9 m longer than those observed from the otway basin this discrepancy is interpreted to reflect up to 40 ma longer residence times at maximum burial temperatures for the otway basin samples standard deviations about mean lengths are also lower than observed in the otway basin study consistent with the wider variation of cl contents mean 0 8 wt 0 7 wt that characterize apatite from the otway basin recently published apatite fission track annealing models predict significantly different mean track length vs present day temperature profiles for thermal histories believed to be representative of those experienced by sampled south texas strata because of the large uncertainties attributed to present day temperatures 10 c the predicted mean length vs temperature trends for these models essentially fall within or on the uncertainty envelope for the observed trend residuals of predicted minus observed mean lengths suggest that the previously published carlson composite parameter model using an initial mean length of 15 8 m instead of 16 5 m or the crowley et al model for track length reduction down to 11 m provide the best estimates of mean track length reduction over geologic time scales for near end member f apatite populations

lower cretaceous provenance and sedimentary deposition in the eastern carpathians inferences for the evolution of the subducted oceanic domain and its european passive continental margin

provenance and thermal history of the franciscan accretionary complex constraints from zircon fission track thermochronology the franciscan accretionary complex of california contains large belts of sediments that were subducted to depths of 10 to 30 km metamorphosed under high pressure and low temperature conditions and later returned to the surface reconnaissance zircon fission track ft data 21 samples place constraints on the sedimentary provenance thermal history and or exhumation history of various franciscan units in a transect across the northern coast ranges through mendocino pass metagraywacke samples from the valantine springs formation of the franciscan eastern belt experienced maximum temperatures tmax ranging from 250 to 310 c zircon ft and previously reported apatite ft data indicate that parts of the western eastern and eastern central belts cooled at about 100 70 ma from 300 c to 100 c considering the low paleogeothermal gradient of roughly 9 c km during franciscan subduction these rocks were apparently uplifted and exhumed from 30 to 10 km depth at this time one sample from the eyler mountain sequence in the northwestern diablo range similarly shows tmax 310 c and major cooling at 100 70 ma this uplift and exhumation may have reflected accelerated accretion at the base as well as the front of the franciscan wedge accompanied by extensional thinning at shallower levels as a result of massive sediment influx into the franciscan trench from the sierra nevada magmatic arc in the northern coast ranges the western part of the central belt and the coastal belt experienced lower tmax probably 200 c and retain source area detrital zircon ft ages burnt hills terrane samples in the diablo range also experienced tmax 230 c and retain detrital ages the detrital single grain age patterns from these areas are compatible with those expected from the sierra nevada magmatic arc and its country rocks this is consistent with derivation of franciscan sediments from arc terranes in california and provides no particular suggestion that these parts of the franciscan are highly allochthonous paleogene coastal belt sandstones also yield detrital ages compatible with derivation from the sierra nevada but also include early tertiary zircon populations compatible with reconstructions suggesting these sandstones were sourced partly from the idaho batholith

tertiary palaeomagnetic data for the carpatho pannonian region in the light of miocene rotation kinematics abstract the tectonic interpretation of the palaeomagnetic data for the neogene history of the carpatho pannonian region has usually been based on the palaeomagnetic data for the pre cenozoic complexes here a review of the tertiary palaeomagnetic data is given for the sites with two or more sets of data new site mean directions are calculated for most areas new area mean directions are given with a uniform criterion for the limitation of the normally distributed sub populations based on radiometric data some neogene volcanic sequences are subdivided into two complexes with separate area mean directions the possible influence of the areal tilts on the area mean palaeomagnetic directions is analysed and conclusions on the horizontal rotations are drawn the palaeomagnetic rotations are interpreted in the light of the author s kinematic model for the neogene history of the carpatho pannonian region the rotation of both the southeastern unit by about 100 clockwise and the northwestern unit by about 35 anti clockwise are supported by palaeomagnetic data in addition some rotations predicted by the model are documented by palaeomagnetic data as follows 1 the anti clockwise rotation of the flanks of the darno line gemer bukk area with sinistral displacements in the early miocene 2 the anti clockwise rotations along the southeastern margin of the northwestern unit with sinistral displacements before 10 ma 3 the anti clockwise rotation of the ukrainian carpathians before 12 ma some palaeomagnetic rotations have not been predicted by the kinematic model but occur in the regions where deformations are quite probable these unexpected palaeomagnetic rotations throw a new light on some details of the kinematics 1 the advance of the outer west carpathian nappes later than 14 ma is documented by the increased palaeomagnetic inclination of the pieniny andesites 2 the movement of the central and inner west carpathians later than 12 ma is recorded in the palaeomagnetic rotations of the central and east slovakian volcanites this movement seems to reflect a bay of thin crust within the underthrust european plate margin or more precisely the reaction of the eastern contour of the bay on the drag of the northwestern unit towards the northeast by the still rotating southeastern unit the rotation and deformation of the northwestern unit in the miocene have to be taken into account in the reconstructions of the pre neogene situations since they intensely influenced the arrangement of all older palaeotectonic and palaeogeographic zones the southeastern unit also suffered intense rotation and deformation in the miocene unfortunately there are almost no palaeomagnetic data available for its tertiary complexes

rift propagation and eustacy as controlling factors during jurassic inshore and shelf sedimentation in northern east greenland abstract mesozoic sedimentation in northern east greenland was initiated in the middle jurassic with transgression of the peneplaned caledonian basement approximately 1 km of inshore and shelf sediments were deposited in progressively deeper water in middle and late jurassic times the sedimentary sequence is interpreted as resulting from the interplay of fault controlled subsidence borderland uplift and major eustatic sea level changes facies analysis shows that sedimentation in the rift type basin was influenced by fluvial tidal wave and storm related processes

fission track constraints on the thermal and tectonic evolution of the apuseni mountains romania new zircon and apatite fission track ft data including apatite thermal modelling are combined with an extensive literature survey and reconnaissance type structural fieldwork in the eastern apuseni mountains this leads to a better understanding of the complex structural and thermal history of a key area at the boundary between two megatectonic units in the balkan peninsula namely the tisza and dacia mega units following late jurassic obduction of the transylvanian ophiolites onto a part of the dacia mega unit that is the biharia nappe system both units were buried to a minimum of 8 km during late early cretaceous times when these units were underthrust below the tisza mega unit consisting of the present day codru and bihor nappe systems tisza formed the upper plate during early cretaceous austrian east facing orogeny turonian to campanian zircon ft cooling ages 95 71 ma from the bihor and codru nappe systems and the biharia and baia de aries nappes at present the structurally lowest part of the dacia mega unit record exhumation that immediately followed a second cretaceous age i e turonian orogenic event thrusting during this overprinting event was nw facing and led to the overall geometry of the present day nappe stack in the apuseni mountains zircon ft ages combined with thermal modelling of the apatite ft data show relatively rapid post tectonic cooling induced by a third shortening pulse during the latest cretaceous laramian phase followed by slower cooling across the 120 60 c temperature interval during latest cretaceous to earliest paleogene times 75 60 ma cenozoic age slow cooling 60 40 ma was probably related to erosional denudation postdating laramian large scale updoming

age and significance of core complex formation in a very curved orogen evidence from fission track studies in the south carpathians romania abstract twenty four new zircon and apatite fission track ages from the getic and danubian nappes in the south carpathians are discussed in the light of a compilation of published fission track data a total of 101 fission track ages indicates that the getic nappes are generally characterized by cretaceous zircon and apatite fission track ages indicating cooling to near surface temperatures of these units immediately following late cretaceous orogeny the age distribution of the danubian nappes presently outcropping in the danubian window below the getic nappes depends on the position with respect to the cerna jiu fault eocene and oligocene zircon and apatite central ages from the part of the danubian core complex situated southeast of this fault monitor mid tertiary tectonic exhumation in the footwall of the getic detachment while zircon fission track data from northwest of this fault indicate that slow cooling started during the latest cretaceous the change from extension getic detachment to strike slip dominated tectonics along the curved cerna jiu fault allowed for further exhumation on the concave side of this strike slip fault while exhumation ceased on the convex side the available fission track data consistently indicate that the change to fast cooling associated with tectonic denudation by core complex formation did not occur before late eocene times i e long after the cessation of late cretaceous thrusting core complex formation in the danubian window is related to a larger scale scenario that is characterized by the nnw directed translation followed by a 90 clockwise rotation of the tisza dacia block due to roll back of the carpathian embayment this led to a complex pattern of strain partitioning within the tisza dacia block adjacent to the western tip of the rigid moesian platform our results suggest that the invasion of these southernmost parts of tisza dacia started before the late eocene i e significantly before the onset of miocene age rollback and associated extension in the pannonian basin

pre alpine crust in the apuseni mountains romania insights from sm nd and u pb data abstract the apuseni mountains in romania expose pre alpine crustal basement rocks between the carpathian and dinaride segments of the alpine orogen because of a lack of direct constraints the age and plate affinity of the basement rocks have been largely uncertain new sm nd data for key lithotectonic assemblages and u pb zircon data for crosscutting plutons are presented they show the presence of early proterozoic crustal components and help constrain the age and nature of several contrasting pre alpine crustal domains basement rocks of the apuseni mountains consist of a northern granite gneiss terrane somes bounded by an amphibolite granodiorite belt codru a composite igneous belt overprinted by alpine shearing highis biharia and a southern carbonate lens mica schist gneiss terrane baia de aries the northern terrane has yielded tdm model ages ranging from 1 90 to 1 76 ga and nd 0 values ranging from 15 5 to 12 5 the southern terrane has yielded tdm model ages of 1 82 1 69 ga and nd

the mid langhian flooding in the eastern central paratethys integrated stratigraphic data from the transylvanian basin and se carpathian foredeep the mid langhian badenian flooding fully reconnected the semi isolated central paratethys realm with the mediterranean and thereby drastically changed the middle miocene paleogeography of central europe due to the scattered stratigraphic record and scarcity of independent age constraints in some areas the precise age and underlying mechanism are still debated we present integrated chronostratigraphic data from five sections in the eastern part of the system to reconstruct the flooding event distal from the strait to the mediterranean by applying modern mediterranean biochronology planktonic foraminifera and calcareous nannofossils supplemented by an 40ar 39ar age on a tuff we demonstrate that the widespread open marine settings in the nw transylvanian basin were definitely installed after 14 9 ma mmi4d biozone and in most areas before 14 4 ma in the marginal study area in the se carpathian foredeep fully marine conditions likely set in slightly later 14 6 14 4 ma there short lived marine incursions into the brackish environment occurred since the latest burdigalian pre flooding phase the new ages overlap with the flooding in the majority of the central paratethys 14 9 14 4 ma and with marine overflow into the black sea 14 85 ma we suggest that the transgression was driven by subsidence of the pannonian basin by creating accommodation space and diminishing barriers between sub basins but was likely enhanced by a global sea level rise finally we speculate that the scarcity of all calcareous material in the se carpathian foredeep before the mid langhian flooding might be related to pulses of nutrient rich brackish and low ph water from the neighboring black sea basin

petrographic facies analysis of lower and middle jurassic coal seams on the island of bornholm denmark abstract the lower middle jurassic succession on the island of bornholm denmark comprises a wide range of clastic depositional environments lacustrine fluvial coastal plain tidal flat and shallow marine the succession contains a number of coal seams and carbonaceous seams permitting 1 evaluation of the relationship between the different clastic environments and the associated environments of organic matter deposition and 2 assessment of facies changes within coal carbonaceous seams from different peat forming environments coal petrographic facies analysis was performed by maceral analysis of 61 coal samples from the lower jurassic ronne formation comprising the munkerup member sose bugt member and galgelokke member and from the upper lower middle jurassic baga formation the seams in the munkerup member and the sose bugt member are mainly allochthonous whereas those of the galgelokke member and the baga formation are mainly autochthonous the seams represent a broad spectrum of depositional environments from raised bogs to freshwater swamps and marine influenced swamps the facies are subaquatic to telmatic and terrestrial compositional differences between the seams are attributed to vegetation characteristics depositional facies and differences in the degradation of the organic matter the original peat forming vegetation was composed of cellulose rich shrub like plants tree ferns herbaceous plant communities and a varying amount of trees the peat forming environments represented by the carbonaceous seams in the munkerup and sose bugt members are compatible with the depositional environments indicated by the sediments however the coal seam in the galgelokke member represents deposition in a raised bog conflicting with sedimentary interpretation of a clastic tidal flat environment for the member the baga formation is considered to have formed under a lower upper delta plain or fluvial environment the composition of the coal seams supports the interpretation of a system of meandering streams in a upper delta plain to fluvial environment

miocene tectonics of the maramures area northern romania implications for the mid hungarian fault zone the interplay between the emplacement of crustal blocks e g alcapa tisza dacia and subduction retreat is a key issue for understanding the miocene tectonic history of the carpathians coeval thrusting and basin formation is linked by transfer zones such as the mid hungarian fault zone which seperates alcapa from tisza dacia the presented study provides new kinematic data from this transfer zone early burdigalian 20 5 to 18 5 ma se directed thrusting of the easternmost tip of alcapa pienides over tisza dacia is linked to movements along the mid hungarian fault zone and the periadriatic line accommodating the lateral extrusion of alcapa minor late burdigalian 18 5 to 16 ma ne sw extension is interpreted as related to back arc extension post burdigalian post 16 ma ne sw shortening and nw se extension correlate with soft collision of tisza dacia with the european foreland coupled with southward migration of active subduction during this stage the bogdan voda and dragos voda faults were kinematically linked to the mid hungarian fault zone sinistral transpression 16 to 12 ma at the bogdan voda fault was followed by sinistral transtension 12 10 ma along the coupled bogdan dragos voda fault system during the transtensional stage left lateral offset was reduced eastwards by sw trending normal faults the fault system finally terminating in an extensional horse tail splay

characteristics of collisional orogens with low topographic build up an example from the carpathians sequence stratigraphy in the hinterland kinematic analysis of thin skinned thrusting in the foreland and thermochronological tracking of exhumation in the orogenic core are combined to quantify the mechanics of an orogen with low topographic build up the carpathian system demonstrates that collisional deformation can couple and thicken the lower orogenic plate along reverse faults that dip more steeply than the subduction zone defining a foreland coupling type of collision near the surface this is expressed by wide antiforms in the upper plate and the thin skinned orogenic wedge a sequence stratigraphic analysis of the back arc transylvanian basin demonstrates that the sedimentary architecture records orogenic uplift pulses with both short and long wavelengths these correspond to the activation of individual thrust sheets in the thin skinned wedge and to lower plate coupling events respectively

modelling the coupling between salt kinematics and subsidence evolution inferences for the miocene evolution of the transylvanian basin large scale diapiric salt movements affect the architecture of sedimentary basins and often prevent the understanding of their mechanics by hiding or distorting subsidence patterns one good example is the evolution of the transylvanian basin which formed during miocene times in an area located in between the rapid slab rollback and continental collision recorded at the exterior of the carpathians and the extension of the neighbouring pannonian basin in the absence of major genetic fault systems quantifying these external tectonic forcing factors requires an accurate reconstruction of subsidence evolution having the advent of a detailed 3d geometrical model of the transylvanian basin we apply a 3d numerical modelling technique that couples salt re distribution and subsidence evolution to quantify and understand the basin kinematics and vertical motions two techniques backward and forward modelling are coupled in order to discriminate between salt migration driven by overburden and the influence of external tectonic forcing factors the results show that salt kinematics was more complex than simple unidirectional migration suggesting the existence of areas with significant subsidence hidden by the inward salt migration and areas with apparent large subsidence that are in reality artefacts of outwards salt migration additionally the results suggest that parts of the basin have been successively affected by in and out ward salt migration events an effect of localising subsidence and overburden furthermore accelerated moments of salt migration took place during the main miocene contraction events recorded at the exterior of the carpathians demonstrating that salt migration is enhanced by intraplate stresses our study also infers that the subsidence of the transylvanian basin is the result of the superposition of the contraction at the exterior of the orogenic chain and the back arc extension

detrital zircon fission track ages for the hoh formation implications for late cenozoic evolution of the cascadia subduction wedge we report new fission track ft ages for detrital zircons for 34 sandstone samples and 2 volcanic ash beds from the hoh formation exposed along the western side of the olympic mountains of western washington state the hoh formation is now formally known as the coastal unit of the olympic structural complex or coastal osc for short about 35 zircons were dated per sample the fission track grain age ftga distributions are all strongly discordant grain ages range from 10 to older than 100 ma low vitrinite reflectance values short etch times for the zircons and a broad range of grain ages indicate that the zircon ft ages are unreset and thus preserve information about cooling events in the source region for these sedimentary rocks five areas were sampled repeatedly and yield similar ftga distributions demonstrating that sampling errors are not a problem we show that almost all of the samples contain a well defined young component that was probably derived from a contemporaneous active volcanic source presumably the adjacent cascadia arc binomial peak fitting was used to estimate the ft minimum age which is the age of the youngest concordant fraction of zircon ft grain ages in a ftga distribution in most cases minimum ages are similar to fossil ages where available this result supports our contention that zircon ft minimum ages from volcaniclastic sandstones commonly can be used as a proxy for depositional age our zircon ft minimum ages indicate that the coastal osc is made up mainly of lower miocene ca 24 to 16 ma sedimentary rocks we use these age data together with other geologic constraints to reconstruct a tectonic history sedimentary rocks of the coastal osc were derived from a mixed source region that included an active volcanic arc and also older units including cretaceous metamorphic rocks probably located in the omineca crystalline belt in the canadian rockies the upper part of the clallam formation located on the northern side of the olympic peninsula appears to be a remnant of the sedimentary system that fed the coastal osc the sediments that formed the coastal osc were initially deposited seaward of the cascadia trench at water depths of 2000 m this debris was deposited seaward of the cascadia trench at water depths of 2000 m and subsequently accreted beneath the frontal 50 to 100 km of the wedge owing to continued accretion at the front of the wedge and erosion of the forearc high in back of the wedge these lower miocene sediments were moved rearward within the cascadia subduction wedge a simple relationship based on the cross sectional area of the wedge and a steady accretion flux indicates that it would have taken 22 m y for the coastal osc to reach its present position 140 km landward of the toe of the wedge this estimate is in good agreement with the unit9s early miocene age

geochronological and structural constraints on the cretaceous thermotectonic evolution of the kraishte zone western bulgaria 1 in the kraishte region near the junction of the balkanides and dinarides late early cretaceous compression led to the thrusting of the morava unit over the struma unit structural investigations combined with zircon fission track and 40ar 39ar analyses have been used to reconstruct the geological history of the area and to clarify the original tectonic position of the main units before cenozoic extension the results show that early cretaceous lower amphibolite facies metamorphism and deformation in the osogovo lisets metamorphic complex were related to top to the ne directed nappe stacking whereas the deeper parts of the allochthonous morava unit experienced low grade metamorphic overprint at temperatures 260 c the structurally intermediate struma diorites and their mesozoic cover experienced temperatures between 170 c and 300 c thrusting of the morava onto the struma unit started probably in valanginian times 140 136 ma soon after the cessation of preorogenic to synorogenic turbidite sedimentation on struma the metamorphic peak was reached before 112 ma subsequent extension related cooling of both units was probably accompanied by the formation of low angle normal faults

tectonothermal evolution of the apuseni mountains romania resolution of variscan versus alpine events with 40ar 39ar ages abstract polyphase alpine transcurrent faulting and thrusting in the apuseni mountains in romania resulted in the juxtaposition of contrasting structural units that include both metamorphic assemblages and permian mesozoic cover resolution of the chronology of alpine events and distinction from pre alpine evolution has been possible by systematic 40ar 39ar mineral dating of medium and low grade assemblages hornblende and muscovite within nonretrogressed northern sectors of the somes gneissic assemblage record rapid postmetamorphic cooling between 317 and 300 ma following a regionally penetrative late variscan tectonothermal overprint the codru amphibolite granodiorite assemblage records markedly older 40ar 39ar mineral ages 400 365 ma hornblende 340 335 ma muscovite that date delayed postmetamorphic cooling following early variscan tectonothermal activity although variably overprinted during mesozoic tectonism late variscan tectonothermal activity 320 300 ma is also evident from analysis

source rock analysis and petroleum geochemistry of the trym discovery norwegian north sea a middle jurassic coal sourced petroleum system abstract the 3 7 4 well trym in the norwegian part of the sogne basin north sea discovered condensates in middle jurassic reservoir sandstones and in addition penetrated four middle jurassic coal seams 0 14 0 56 m thick the precursor peats of the coals which have a complex vitrinite and inertinite rich composition accumulated in coastal plain mires and the depositional conditions of the peats influenced the source rock potential of the resulting coals vitrinite reflectance values from 0 86 0 87 r o and an average t max of 438 c indicate that the coals are thermally mature but they may be interpreted only to be in the early phase of petroleum generation the hydrogen indices of the coals are generally below 200 and crude oil saturation of the coals may have been hindered by an uneven in seam distribution of favourable hydrogen indices 200 coupled with the comparatively thick seams condensate source rock correlations indicate a similarity between the trym condensates and extracts from the coals in the 3 7 4 well and stable carbon isotope data infer a common source for the trym condensates and the condensates and oils from the harald and lulita fields in the danish part of the sogne basin the harald and lulita fields have recently been proven to represent a middle jurassic coal sourced petroleum system the lulu bryne lulu petroleum system and the trym condensate discovery is thus another example of this petroleum system which may be more widespread in the central graben

palaeomagnetic study of some neogene magmatic rocks from the oas ignis văratec tibles mountains romania summary for this palaeomagnetic study 199 sites were sampled in the northern part of the east carpathians oas ignisl v ratec tibles sector after af alternating field demagnetization 155 sites were selected for further analyses a good agreement between the measured palaeomagnetic poles for the pontian the pannonian and the reference polar wander path of eurasia was made evident in the southern part of the ignis mountains the sarmatian volcanic rocks were affected by a 30 counterclockwise rotation with respect to europe post emplacement

the eastern carpathians ophiolites romania remnants of a triassic ocean abstract mesozoic ophiolitic and related rocks in the eastern carpathians occur in three areas from north to south rar u h ghimas and persani mts they are found as blocks ranging from few metres to a few kilometers in size and as centimetre sized in breccias most likely embedded in the late barremian early albian wildflysch formation compositionally they range from lherzolites and harzburgites to mafics such as feti gabbros dolerites basalts and to andesites the volcanics comprise highly depleted basalts andesites to enriched type mid ocean ridge basalts additionally they include ocean island basalts and calc alkaline basalts andesites and trachytes based on paleontological evidence their age is middle to late triassic they can be clearly compared with remnants of the meliata hallstatt ocean in the western carpathians but do not match the jurassic ophiolites and island arc volcanics in the mures zone of the southern apuseni mts we propose a triassic ocean connected with the meliata hallstatt ocean between a the bucovinian sub bucovinian continental crust b the infrabucovinian and finally c the northern apuseni microcontinents this ocean closed in the late triassic to early jurassic causing close juxtaposition of all three microcontinents an ophiolite complex together with ocean island basalts and calc alkaline basalts andesites remained from this ocean and was subsequently eroded and transported as blocks of different size into the lower cretaceous wildflysch basin together with blocks and clasts of limestones similar to the mesozoic sedimentary sequences in the northern apuseni realm the wildflysch formation was thrust as an independent unit during the albian over the bucovinian nappe in the eastern carpathians and the northern apuseni continental crust respectively

three dimensional numerical models with varied material properties and erosion rates implications for the mechanics and kinematics of compressive wedges received 19 march 2008 revised 29 january 2009 accepted 13 february 2009 published 21 april 2009 1 we develop three dimensional mechanical models of a compressive wedge and investigate how the form and kinematics of the outboard wedge are affected by variation in initial topography material properties and erosion rate inclusion into the wedge of weaker less dense material affects the form of the wedge producing a region of steeper average slopes and higher topography while depriving the region further inboard of material enhanced erosion has a similar effect the wedge attempts to replace the eroded material by focusing deformation the result is a stepped region of lower topography within the outboard of the orogen we observe that uplift velocities at three points in the orogen vary cyclically from near zero to 3 times the average uplift rate over cycles lasting on the order of 15 200 000 model years our models along with analog models and some well dated examples from active orogens suggest that transient accommodation of strain may be common the cycles observed responded rapidly to changes in the amount of erosion imposed our models suggest that orogens may be driven by strong coupling between erosion and strain on temporal scales of 10 4 10 5 years and spatial scales comparable to the scale of the erosional perturbation we compare our models to the puli embayment of west central taiwan a region of anomalous low topography and suggest that it presence may reflect the presence of weaker and more erodible sediments than those present along strike in the orogen

mesozoic plate tectonic reconstruction of the carpathian region abstract palaeomagnetic palaeobiogeographic and structural comparisons of different parts of the alpine carpathian region suggest that four terranes comprise this area the alcapa tisza dacia and adria terranes these terranes are composed of different mesozoic continental and oceanic fragments that were each assembled during a complex late jurassic cretaceous palaeogene history palaeomagnetic and tectonic data suggest that the carpathians are built up by two major oroclinal bends the alcapa bend has the meliata oceanic unit correlated with the dinaric vardar ophiolite in its core it is composed of the western carpathians eastern alps and southern alcapa units transdanubian range bukk this terrane finds its continuation in the high karst margin of the dinarides further elements of the alcapa terrane are thought to be derived from collided microcontinents czorsztyn in the n and a carbonate unit tisza in the se the tisza dacia bend has the vardar oceanic unit in its core it is composed of the bihor and getic microcontinents this terrane finds its continuation in the serbo macedonian massif of the balkans the bihor getic microcontinent originally laid east of the western carpathians and filled the present carpathian embayment in the late palaeozoic early mesozoic the vardar ocean occupied an intermediate position between the western carpathian austroalpine transdanubian high karst margin and the bihor getic serbo macedonian microcontinent the vardar and pindos oceans were opened in the heart of the mediterranean adriatic microcontinent in the late permian middle triassic vardar subducted by the end of jurassic causing the bihor getic serbo macedonian microcontinent to collide with the internal dinaric western carpathian margin an external penninic vahic ocean tract began opening in the early jurassic separating the austroalpine western carpathian microcontinent and its fauna from the european shelf further east the severin ceahlau magura also began opening in the early jurassic but final separation of the bihor getic ribbon and its fauna from the european shelf did not take place until the late middle jurassic the alcapa and the tisza dacia were bending during the albian maastrichtian the two oroclinal bends were finally opposed and pushed into the gates of the carpathian embayment during the palaeogene and neogene at that time the main n s shortening in distant alpine and hellenic sectors was linked by a broader right lateral shear zone along the former vardar suture

structural evolution of the transylvanian basin romania a sedimentary basin in the bend zone of the carpathians abstract the transylvanian basin with its up to 10 km thick upper cretaceous to pliocene fill is one of the most important sedimentary basins of southeastern europe upper cretaceous coarse grained clastics lie unconformably on basement strongly tectonized during early cretaceous and older stages upper cretaceous sediments were mainly deposited along roughly n s trending grabens and were subsequently folded before the end of the paleocene eocene to middle oligocene rocks record mostly quiet sedimentation n s tension and extension took place in the oligocene and was followed by widespread nw se compression and contraction important thrusts are associated with this phase in the northwestern and southeastern parts of the basin widespread n s contraction followed during the early miocene in association with s vergent thrusting in the northern part of the basin a southward thinning clastic wedge developed during this stage the badenian basal unconformity marked a major change in the sedimentary and tectonic pattern of the transylvanian basin with new depocenters developing in the central parts of the present day basin late miocene e w extension affected vast areas and caused some important normal faulting in the southeast the youngest deformation recorded is associated with e w contraction and is of pliocene or younger age

tertiary cooling and exhumation history in the maramures area internal eastern carpathians northern romania thermochronology and structural data the tertiary kinematic history of the maramures area is constrained by integrating thermochronological fission track and uth he analysis data with field based structural investigations this study focuses on the tectonic evolution of the northern rim of the tisza dacia block during collision with the european margin cretaceous nappe stacking related metamorphism as well as late cretaceous exhumation are evidenced by zircon fission track data subsequent palaeogene to early miocene sedimentation led to burial heating and annealing of fission tracks in apatite final tectonic uplift was initiated during the convergence of tisza dacia with the european margin associated with transpressional deformation 16 to 12 ma this led to mid miocene exhumation recorded by apatite fission track cooling ages in the western part of the study area transtension between 12 and 10 ma caused brittle deformation along ew trending strike slip faults and swne trending normal faults delimiting blocks that were tilted towards the sw this fragmentation of the crust led to enhanced exhumation at rates of 1 mm a in the central part of the study area as is documented by middle to late miocene cooling ages 13 to 7 ma the outside estimate for the total amount of exhumation since middle miocene times is 7 km

3 geochronology and geodynamics of late cretaceous magmatism and cu au mineralization in the panagyurishte region of the apuseni banat timok srednogorie belt bulgaria abstract the apuseni banat timok srednogorie abts belt europe s most extensive belt of calc alkaline magmatism and cu au mineralization is related to the subduction of the tethys ocean beneath the european continental margin during the late cretaceous phase of the alpine himalayan orogeny economic deposits are restricted to certain segments along the belt and all major porphyry style and high sulphidation ore deposits in bulgaria are aligned on the panagyurishte corridor a narrow zone obliquely crossing the abts belt this paper reviews the geology geochemistry and geochronology of igneous and hydrothermal events along this corridor in a profile extending from the european continental basement in the north to the accretionary complex of the rhodopes in the south extensive u pb dating of zircons from subvolcanic intrusions and major plutons supplemented by published age data for magmatic rocks and hydrothermal ore deposits obtained by other methods reveals a general younging of magmatism from ca 92 ma in the north elatsite to ca 78 ma in the south capitan dimitrievo cu au deposits are restricted to the northern and central parts of the profile ranging in age from 92 to 86 ma while the southernmost part exposes more deeply eroded mid crustal plutons devoid of economic mineralization the age progression correlates with a north to south geochemical trend of decreasing crustal input into mantle derived magmas magmatism and ore formation in individual magmatic hydrothermal complexes along the profile is much shorter lived for example subvolcanic intrusions and porphyry cu au mineralization at the elatsite deposit and andesitic volcanism and high sulphidation au as cu mineralization at chelopech all occurred within a time span of about 1 million years the age progression of calc alkaline magmatism within the panagyurishte region bulgaria from north to south is explained as a consequence of slab retreat during oblique subduction this led to transtensional block faulting and subsidence and thus to the preservation of near surface magmatic hydrothermal products including economic cu au deposits accretion of continental fragments in the rhodopes south of the abts belt led to greater uplift of the youngest late cretaceous intrusions this removed any ore deposits that might have been formed in this area

high resolution sequence stratigraphy of a hettangian sinemurian paralic succession bornholm denmark sequence stratigraphic interpretation of paralic successions is complicated by the complex interfingering of marine and continental strata the successions may also include terrestrial extensions of marine parasequences and completely independent lacustrine parasequence analogues failure in recognizing the possible interbeddding of these two independent parasequence types may lead to construction of sequence stratigraphic schemes based on incompatible data sets we have studied a lower jurassic paralic section from the baltic island of bornholm situated in the tornquist zone which demarcates the transition from the stable precambrian baltic shield to the subsiding danish basin and danish polish trough the hettangian sinemurian sose bugt member ronne formation of bornholm includes lacustrine fluvial and restricted marine estuarine deposits reflecting the basin margin position biostatigraphic resolution is poor and a sequence stratigraphic interpretation of the paralic succession is far from straightforward a multidisciplinary approach including facies analysis recognition and lateral trading of key surfaces palynostratigraphy palynofacies coal petrography palaeopedology clay mineralogy and source rock geochemistry is applied in order to obtain a high degree of precision in the interpretation of the paralic facies in this way four sequences are recognized in the overall backstepping lacustrine to estuarine succession marine and marginal marine parasequences are distinguished from their purely lacustrine analogues and an internally consistent sequence stratigraphic scheme is proposed this is compared and tentatively correlated with fossiliferous marine sediments in the danish basin and with published eustatic cycle charts

annealing kinetics of fission tracks in zircon an experimental study a series of laboratory annealing experiments on zircon fission tracks has been carried out under heating conditions of 350 750 c for 10 1 103 hr i e 4 5 min 40 days variation in the confined lengths of spontaneous fission tracks was determined using zircon grains from nisatai dacite the fading contours of normalized mean track length r on the arrhenius diagram showed as sets of straight lines we performed a series of model fittings called the parallel and fanning models in order to describe the decrease in r with increasing temperature or heating time the lowest temperature limit of the zircon partial annealing zone zpaz was defined as r 0 95 and the highest as r 0 4 which approximately corresponded to the total fading of surface tracks extrapolation of the results of the laboratory experiments to the geological timescale gives for a heating duration of 106 yr estimated values of the zpaz of 210 320 c 60 c 2 with the parallel model 190 350 c 50 c 2 with the fanning model critical temperature t0 and 170 390 c 50 c 2 with the fanning model t0 the temperatures of the zpaz decrease by 20 c for an annealing duration that is an order of magnitude longer because the estimated closure temperature of zircon fission track analysis approximately corresponds to the middle of the zpaz these results support the previously estimated closure temperature of 240 c by varying the etching time it was revealed that significant removal of radiation damage occurs at r 0 93

tectonic configuration of the apuseni banat timok srednogorie belt balkans south carpathians constrained by high precision r e o s molybdenite ages the apuseni banat timok srednogorie magmatic metallogenic belt abts belt forms a substantial metallogenic province in the balkan south carpathian system in southeastern europe the belt hosts porphyry skarn and epithermal deposits mined since pre roman times generally the deposits prospects and occurrences within the belt are linked to magmatic centers of calc alkaline affinity fifty one rhenium osmium re os ages and re concentration data for molybdenites define systematic geochronologic trends and constrain the geochemical metallogenic evolution of the belt in space and time from these data and additional existing geologic geochemical data a general tectonic history for the belt is proposed mineralization ages in apuseni banat timok and panagyurishte the central district of the larger e w srednogorie zone range from 72 83 81 88 and 87 92 ma respectively and clearly document increasing age from the northwestern districts to the southeastern districts further re os ages suggest rapidly migrating pulses of late cretaceous magmatic hydrothermal activity with construction of deposits in 1 m y districts in 10 m y and the entire 1 500 km belt in 20 m y ages in both timok and panagyurishte show systematic younging while deposit ages in banat and apuseni are less systematic reflecting a restricted evolution of the tectonic system systematic differences are also observed for molybdenite re concentrations on the belt scale re concentrations generally range from hundreds to thousands of parts per million typical of subduction related cu au mo pge porphyry systems associated with the generation of juvenile crust the geochronologic and geochemical trends are compatible with proposed steepening of subducting oceanic slab and relaxation of upper continental plate compression resulting influx of sub continental mantle lithosphere scml and asthenosphere provide a fertile metal source and heat while the subducting slab contributes connate and mineral dehydration fluids which facilitate partial melting and metal leaching of scml and asthenosphere cu au mo pge porphyry deposits may develop where melts are trapped at shallow crustal levels often with associated volcanism and epithermal style deposits south banat timok and panagyurishte mo fe pb zn skarn deposits may develop where felsic melts are trapped adjacent to mesozoic limestones at moderate crustal levels north banat and apuseni systematic spatial variations in deposit style commodity enrichment re os ages and re concentrations support specific tectonic processes that led to ore formation in a post collisional setting subduction of vardar oceanic crust may have stalled causing slab steepening and rollback the slab rollback relaxes compression facilitating and enhancing orogenic collapse of previously thickened balkan south carpathian crust the progression of coupled rollback orogenic collapse is evidenced by the width of late cretaceous extensional basins and northward younging of re os ages from panagyurishte 60 km 92 87 ma to timok 20 km 88 81 ma to apuseni banat 5 km 83 72 ma generation of a well endowed mineral belt such as the abts requires a temporally and spatially restricted window of magmatic hydrothermal activity this window is quickly opened as upper plate compression relaxes thereby inducing melt generation and ingress of melt to higher crustal levels the window is just as quickly closed as upper plate compression is reinstated the transient tectonic state responsible for economic mineralization in the abts belt may be a paleo analogue to transient intervals in the present subduction tectonics of se asia where much mineral wealth has been created in the last few million years

tectonic units of the alpine collision zone between eastern alps and western turkey abstract we present a map that correlates tectonic units between alps and western turkey accompanied by a text providing access to literature data explaining the concepts used for defining the mapped tectonic units and first order paleogeographic inferences along strike similarities and differences of the alpine eastern mediterranean orogenic system are discussed the map allows 1 for superimposing additional information such as e g post tectonic sedimentary basins manifestations of magmatic activity onto a coherent tectonic framework and 2 for outlining the major features of the alpine eastern mediterranean orogen dinarides hellenides anatolides and taurides are orogens of opposite subduction polarity and direction of major transport with respect to alps and carpathians and polarity switches across the mid hungarian fault zone the dinarides hellenides taurides and apennines consist of nappes detached from the greater adriatic continental margin during cretaceous and cenozoic orogeny internal units form composite nappes that passively carry ophiolites obducted in the latest jurassic earliest cretaceous or during the late cretaceous on top of the greater adriatic margin successions the ophiolites on top of composite nappes do not represent oceanic sutures zones but root in the suture zones of neotethys that formed after obduction suturing between greater adria and the northern and eastern neotethys margin occupied by the tisza and dacia mega units and the pontides occurred in the latest cretaceous along the sava izmir ankara erzincan suture zones the rhodopian orogen is interpreted as a deep crustal nappe stack formed in tandem with the carpatho balkanides fold thrust belt now exposed in a giant core complex exhumed in late eocene to miocene times from below the carpatho balkan orogen and the circum rhodope unit its tectonic position is similar to that of the sakarya unit of the pontides we infer that the rhodope nappe stack formed due to north directed thrusting both rhodopes and pontides are suspected to preserve the westernmost relics of the suture zone of paleotethys

sequence stratigraphy and paleogene tectonic evolution of the transylvanian basin romania eastern europe abstract the transylvanian basin of romania belongs to the 800 400 km wide pannonian domain of the european alpine megasuture bordered to the east and the north by the carpathians it represents a digitation of the epicontinental tethyan seaways locally connected during the palaeogene to the peripheral foredeep troughs during that time it was filled up by a 500 m thick sediment pile organized into three shallow marine and non marine facies alternations each evolved from alluvial fans to restricted marine and outer marine environments they are dated from lutetian to chattian times the study is focused on the lowermost alternation onlapping the basal post maastrichtian unconformity this alternation consists of the superimpossition of a thick retrogradational and a thin progradational depositional system the retrogradational depositional system grades upwards from stacked fault controlled deposits of alluvial fan ephemeral stream salina and sabkha and restricted marine bioclastic shales the progradational depositional system is composed of outer marine to estuarine sandstones and shales the two depositional systems are bounded at their tops by two baselevel change unconformities underlain by highly mobile low relief sandstone bodies that were deposited in shoal belts these two unconformities mark significant changes in the regime of the subsidence these are respectively a baselevel rise or drowning unconformity where the shoal deposits were associated with oolitic ironstones and glauconitic shales that typify basin starvation during a period of maximum basin drowning and a baselevel fall or uplifting unconformity where the bioclastic shoal deposits were buried by alluvial flood plain deposits that characterize periods of relief rejuvenation tentatively attributed to compressive events this bimodal succession is interpreted in terms of underfilled overfilled stages related to intraplate tectonic deformation the underfilled stage corresponds to the fault controlled drowning of the basin and the overfilled stage to the increasing flexural rigidity of the substrate culminating in differential uplift in the area three of these successions comprise the palaeogene sedimentary record of the transylvanian basin they attest to a large scale pulsating evolution of this continental microplate during its northward migration towards the european plate

late cambrian ordovician northeastern gondwanan terranes in the basement of the apuseni mountains romania abstract the pre alpine basement of the apuseni mountains romanian carpathians comprises three terranes somes baia de aries and biharia metaigneous rocks within these terranes record late cambrian ordovician u pb zircon crystallization ages two samples from an orthogneiss layer in the somes terrane yielded an age of 459 8 2 7 ma in the baia de aries terrane an augen gneiss yielded an age of 470 8 3 8 ma a porphyroid yielded an age of 467 8 3 8 ma and two metagranites yielded ages of 467 8 4 7 ma and 467 1 3 9 ma respectively three samples from a metagranitoid outcrop located in the lower part of the biharia terrane yielded an age of 495 0 2 1 ma three other samples from a metabasite layer situated lithostratigraphically several hundred metres above the metagranitoid yielded an age of 477 8 3 2 ma detrital u pb zircon ages from a paragneiss interlayered within the baia de aries terrane scatter between 548 and 3518 ma detrital zircon ages together with the inherited ages recorded by magmatic zircon populations suggest a northeastern gondwanan provenance for the somes baia de aries and biharia terranes adjacent to the arabian nubian shield lead loss in some zircons is interpreted to have taken place during the variscan orogeny supplementary material coordinates for samples from the apuseni mountains palaeozoic palaeogeographical models of gondwana laurentia and baltica to the formation of pangaea sample preparation and analytical procedures sample description and age measurements of zircon grains are available at http www geolsoc org uk sup18425

composition and organic maturity of middle jurassic coals north east greenland evidence for liptinite induced suppression of huminite reflectance abstract middle jurassic coals from kuhn o north east greenland may contain up to 85 vol liptinite principally resinite up to 68 6 vol the coals are thus petrographically comparable to the middle jurassic muslingebjerg formation coals at hochstetter forland approximately 40 50 km to the north and they are inherently excellent petroleum source rocks liptinite poor 6 0 vol coal samples from both kuhn o and hochstetter forland yield mean random huminite reflectance values of 0 49 0 53 ro implying a rank of sub bituminous a above a threshold value somewhere between 3 and 24 vol resinite and 6 and 35 vol total liptinite significant reflectance suppression is induced and between 24 and 69 vol resinite and 35 and 85 vol total liptinite a nearly linear inverse relationship exists between the content of liptinite resinite and the mean random reflectance values at the highest liptinite resinite contents reflectance suppression may be up to 0 23 ro the reflectance suppression is related to bitumen adsorption caused by bitumen expulsion from resinite and total reflectance distributions of the huminite fractions suggest that the reflectance of all huminite macerals is lowered with increasing liptinite resinite content

organic facies development within middle jurassic coal seams danish central graben and evidence for relative sea level control on peat accumulation in a coastal plain environment abstract during middle jurassic times peat accumulated in coastal plain environments in an overall transgressive setting in the sogne basin danish central graben in the north sea the coal seams occur in nonmarine to marginal marine deposits coal petrographic analyses of the seams in the west lulu 2 well supplemented with a sequence stratigraphic analysis suggest that peat accumulation was controlled by relative sea level changes in west lulu 2 the coal bearing upper part of the middle jurassic is divided into sequences a and b the sediments of sequence a are part of a transgressive systems tract whereas the overlying sequence b contains lowstand and transgressive systems tract deposits the coals are situated in the transgressive systems tracts the coal seams formed during a rapid relative sea level rise are generally characterized by petrographic features related to a permanently high groundwater table coals formed during a slow rise typically are drier in their petrographic composition the highest pyrite contents are observed in the wet coals the coal seams represent terrestrial equivalents to marine flooding surfaces or to transgressive surfaces if they are situated at the base of a transgressive systems tract a thick coal seam zone is associated with the stratigraphic level of the maximum flooding surface which correlates with the time of formation of the highest accommodation space

zircon fission track thermochronology and applications to fault studies zircon is one of the most useful minerals used to unravel the earth s history recorded in rocks after the success of etching fission tracks in zircon fleischer et al 1964 naeser 1969 krishnaswami et al 1974 early studies focused primarily on dating young volcanic horizons for stratigraphic purposes e g naeser et al 1973 hurford et al 1976 seward 1979 gleadow 1980 kowallis et al 1986 kohn et al 1992 subsequently fission track analysis of zircon has been extensively employed along with other radiometric dating methods such as u pb and u th he techniques e g davis et al 2003 reiners 2005 to understand the thermochronology of rocks in a variety of geological settings i e thermal history analysis of basement rocks for orogenic studies e g zeilter et al 1982 hurford 1986 kamp et al 1989 sorkhabi 1993 seward and mancktelow 1994 hasebe and tagami 2001 spikings et al 2001 thermochronology using detrital zircon grains in sedimentary rocks for provenance analysis and thermal history analysis in or near faults which will be highlighted below in this present chapter the thermal sensitivity of the zircon fission track thermochronometry is reviewed in the context of laboratory and field studies then laboratory procedures of the zircon fission track analysis using the external detector method are outlined as practiced in the fission track laboratory of kyoto university for basic fundamentals of these fission track analyses including data analysis and graphical displays see the chapter by tagami and o sullivan 2005 finally as an example of recent geological applications of the technique the results of zircon fission track analysis of the nojima fault zone japan are presented these rocks were the target of systematic drilling of an active fault system using five boreholes and a trench applications to other geological settings and the