cenomanian turonian facies succession in the guerrero morelos basin southern mexico abstract the cenomanian turonian succession of southern mexico is characterized by an abrupt change from shallow marine to pelagic facies the drowning of the platform coincides with the widely documented cenomanian turonian oceanic anoxic event ctoae a proper understanding of the drowning event and the effects of the oae requires as an essential first step the construction of a detailed stratigraphic framework this has been achieved and utilizes sedimentological data as well as a combination of benthic and planktonic biostratigraphic schemes deposition of the cenomanian turonian sedimentary rocks of the guerrero morelos basin was controlled by tectonic and oceanographic factors resulting in depositional environments ranging from a semi restricted shelf ramp pelagic and prodelta deposits facies analysis indicates that shallow marine limestones of the morelos formation lower upper cenomanian were deposited in intertidal shallow supratidal and subtidal environments in a semi restricted shelf peloidal bioclastic packstone wackestones with minor grainstones are the predominant texture of these rocks abundant large benthic foraminifers calcareous algae dasycladacean and mollusks gastropods and rudists characterize the fossil assemblage the cuautla formation uppermost cenomanian turonian represents sedimentation on a low energy wave dominated carbonate ramp the inner ramp accumulated bioclastic banks and shoals composed of peloidal benthic foraminifer grainstone calcareous red and green algae rudists and minor solitary corals the middle ramp is represented by nodular packstones with a diverse assemblage of echinoderms green and red algae bryozoan rudists solitary corals roveacrinids calcisphaerulids and non keeled planktonic foraminifers the outer ramp is dominated by argillaceous wackestone packstone characterized by calcisphaerulids roveacrinids and non keeled planktonic foraminifers an increase in terrigenous clastic material towards the eastern part of the area indicates progradation of a deltaic system while the mexcala formation uppermost cenomanian turonian was deposited in a pelagic setting the drowning of the platform is at the contact between the morelos and cuautla or mexcala formations and is dated as latest cenomanian the drowning is a hiatus in most sections and it began before the end of the cenomanian by a minimum of 150 ky if the top of the morelos is not eroded

sedimentation in a disequilibrium river dominated estuary the rasa river estuary adriatic sea croatia this paper examines sediment transport sedimentation and properties of suspended matter and sediments in the rasa river estuary a small rock bounded microtidal low wave energy karstic estuary in the north eastern adriatic the rasa river is characterized by large variation in water flow and variable load of mineral particles more than 90 of this load is brought into the estuary as fine grained suspended matter consisting of only 24 36 of carbonates the rest being clays sedimentation occurs at the salt wedge resulting in a prograding estuarine delta salt induced flocculation is the predominant process of sediment deposition the rasa estuary is infilling with sediment and classifies as a disequilibrium estuary we propose a modification of cooper s 1993 classification scheme to include river dominated disequilibrium estuaries with the rasa river as an example

upper cenomanian lower turonian sea level rise and its consequences on the adriatic dinaric carbonate platform the adriatic carbonate platform existed throughout most of the mesozoic as an isolated intraoceanic carbonate platform it is characterized by what has been traditionally labelled a continuous shallow marine carbonate sedimentation without terrigenous influences however global sea level changes left unequivocal imprints in the continuous carbonate record thus proving that the carbonate platform sensitively responded to sea level fluctuations this paper focuses on the relatively short cenomanian turonian drowning event which temporarily submerged the platform below the euphotic zone and which is related here to the well known global cenomanian turonian sea level highstand this drowning episode is characterized by the abrupt disappearance of numerous shallow water benthic invertebrate taxa and by an abundant occurrence of planktonic organisms including calcispheres and primitive planktonic foraminifera near the middle of the turonian the platform regime was re established correlating with the global fall in sea level the situation is different only at the south west margin of the platform where pelagic sedimentation initiated near the end of the cenomanian continues into the santonian and probably marks the adriatic trough the drowning began earlier in the middle cenomanian in those areas nearer to the north east margin of the platform the area of what is today central croatia and then progressed gradually towards the more interior areas of the platform the middle dalmatian islands which were drowned near the end of the cenomanian

response of a carbonate platform to the cenomanian turonian drowning and oae 2 a case study from the adriatic platform dalmatia croatia abstract global perturbations during the cenomanian turonian boundary ctb interval and the oceanic anoxic event 2 oae 2 represent one of the most extensively studied past environmental changes to explore the response of various carbonate platform depositional systems to such major environmental perturbations strata of the intra tethyan adriatic carbonate platform sensu stricto from the island of brac adriatic sea croatia provide excellent exposures and a previously well established upper cretaceous lithostratigraphic framework within this context this study integrated lithostratigraphy biostratigraphy and chemostratigraphy to describe a drowned platform succession underlain and overlain by peritidal carbonates carbon isotope stratigraphy of this succession revealed a shift towards positive 13c values that reached 4 to 5 vpdb and represent the ctb interval excursion plateau we observed variations in thickness of the drowned platform successions and explained them by three superimposed mechanisms 1 diachronous drowning of platform relief 2 intra platform redeposition of parts of the successions by various mass gravity transport processes indicating enhanced instability due to increasing accommodation space related to the late cenomanian platform drowning and synsedimentary tectonics and 3 migration of major carbonate factories during the recovery of shallow platform environments the results indicate that the ctb interval event caused unusual increase in accommodation space on the carbonate platform enabling open marine influence and synsedimentary redeposition however widespread organic rich black shales reported from coeval strata of other regions have not been documented from the platform top successions to date and were probably accumulated in deeper anoxic settings below the rising sea level

the mid cretaceous carbonate system of northern israel facies evolution tectono sedimentary configuration and global control on the central levant margin of the arabian plate

viking formation joffre field alberta shoreface origin of long narrow sand body encased in marine mudstones joffre oil field is long about 38 km or 23 6 mi and narrow 3 4 km or 1 8 2 5 mi and trends northwest southeast production is from the viking formation which consists of cross bedded glauconitic sandstones up to 8 m 26 ft thick encased in bioturbated marine mudstones and siltstones although an overall coarsening upward facies sequence appears to exist the sandstones are separated from the underlying mudstones by two erosion surfaces the lower surface dips northeastward with up to 9 m 29 5 ft of erosional relief this surface truncates facies and log markers and is overlain by a thin veneer of pebbles the upper erosion surface appears to be flat southwest of the field but steps downward about 11 m 36 ft along the length of the southern margin of the field he step is interpreted as an incised shoreface cut during a sea level lowstand during the lowstand sand and granules were supplied to the shoreface by incised rivers and were transported along the shore by tidal and or wave generated currents an ensuing rise of sea level covered the sands with marine muds and planed off any evidence of subaerial exposure southwest of the field leaving only a transgressive lag this interpretation overcomes some of the problems of offshore bar interpretations namely how the sediment was transported across the shelf and molded into ridges with internal coarsening upward sequences apparently 1 the linear nature of the field is due to its formation along the shoreface 2 sediment was not transported across the shelf and 3 relative sea level fl ctuations and consequent shifts in the position of the shoreface control the location of the reservoir sand body

redescription of aigialosaurus dalmaticus kramberger 1892 a cenomanian mosasauroid lizard from hvar island croatia redescription of the type and only specimen of aigialosaurus dalmaticus bsp 1902ii501 an aigialosaurian squamate from the cenomanian turonian of hvar croatia and at the time of collection the italian island of lesina indicates that previous reviews of the specimen include erroneous anatomical interpretations the type specimen presents a new and unique pelvic anatomy the ilium of a dalmaticus is an elongate element with well developed anterior and posterior iliac processes a scenario is presented for mosasaurid pelvic evolution whereby the anteriorly elongate and dorsally directed ilium of mosasauroids is not derived from the forward rotation of the posterior iliac process but rather the reduction of that process and the elaboration of the anterior iliac process recent phylogenetic analysis of mosasauroidea finds a dalmaticus to be the sistergroup to opetiosaurus bucchichi and all other mosasaurids and aigialosaurs we examine the character state assignments for a dalmaticus in that st

geodynamic evolution of the central dinarides abstract the central part of the dinarides unlike the northwestern and southeastern dinarides shows a consistent pattern in the distribution of the large tectonostratigraphic units from southwest apulia to northeast the following five main units originating in different parts of the mesozoic tethys can be distinguished 1 adriatic dinaridic carbonate platform formations 2 carbonate clastic units flysch bosniaque of the passive continental margin 3 ophiolite bearing formations of the dinaridic ophiolite zone also containing radiolarites greywackes and shales including melange formations and overstepped late jurassic to cretaceous cover sequences 4 active continental margin units represented by upper cretaceous palaeogene trench sediments with blueschists tectonized ophiolite melange alpine medium pressure metamorphic rocks originated from upper cretaceous palaeogene sediments and alpine synkinematic granitoids 5 a nappe consisting of allochthonous palaeozoic triassic formations which is thrust onto the ophiolites and genetically related sedimentary formations the frontal parts of this nappe directly overlie the northeastern margin of the adriatic dinaridic carbonate platform i e the external dinarides the evolution of the central dinarides was controlled by a sequence of tectonic events which took place within the alpine cycle 1 rifting processes lasting some 40 50 ma which started in the late permian and ended in the norian 2 opening of the oceanic dinaridic tethys commenced in the late triassic and persisted for some 70 80 ma until the end of the jurassic 3 subduction processes and emplacement of ophiolites started in late jurassic early cretaceous times during the closing phase of the dinaridic ocean or dinaridic tethys the palaeozoic triassic nappe was emplaced on the ophiolites the thrusting was accompanied by alpine metamorphism 120 100 ma 4 the main alpine deformational event and medium pressure metamorphism with synkinematic granite plutonism took place in late eocene early oligocene times when the ophiolite and palaeozoic triassic nappes were emplaced on the adriatic dinaridic carbonate platform which at the same time was deformed resulting in the development of the external dinarides fold and thrust belt

relative sea level changes recorded on an isolated carbonate platform tithonian to cenomanian succession southern croatia abstract superb sections of tithonian to cenomanian carbonates of the adriatic dinaric platform are exposed on the islands of southern croatia a succession approximately 1 800 m thick consists exclusively of shallow water marine carbonates limestone dolomitized limestone dolomite and intraformational breccia formed in a protected and tectonically stable part of the platform interior several phases of exposure and incipient drowning are recorded in the platform interior four are crucial for understanding the late jurassic to mid cretaceous evolution of the wider peri adriatic area 1 latest jurassic earliest cretaceous sea level fall 2 aptian drowning followed by 3 late aptian platform exposure and 4 late albian early cenomanian sea level fall deciphering these complex events from the vertical and lateral facies distribution has led to an evaluation of facies dynamics and construction of a relative sea level curve for the study area this curve shows that long term transgression during the early tithonian hauterivian early aptian and early albian resulted in generally thicker beds deposited in subtidal environments of lagoons or shoals regression was characterized by shallowing upward peritidal parasequences with well developed tidal flat laminites commonly capped by emersion breccia and or residual clay sheets early berriasian barremian late aptian late albian the southern part of the dinarides was tectonically quiet during the tithonian through aptian sea level oscillations appear to have been the primary control on facies stacking some correlation exists between local sea level fluctuations and the published global eustasy charts for the tithonian through aptian a significant departure is recognized at the albian cenomanian transition suggesting that it was influenced by tectonics associated with the disintegration of the adriatic dinaric platform

cretaceous climate a comparison of atmospheric simulations with the geologic record abstract atmospheric simulations using realistic cretaceous geography 100 million years ago suggest that paleography is an important factor governing the nature of the circulation the simulated cretaceous atmospheric circulations are markedly different both from the present day atmospheric circulation and from the classical hypotheses of a weaker circulation and poleward displacement of circulation features e g the subtropical high therefore they pose specific questions which can be tested against the geologic record aspects of the cretaceous simulations are verified in comparisons with the geologic record the simulations serve to guide areas of future paleoclimatic research and to formulate better the nature of the problem of warm equable climates

stratigraphy and paleoenvironments of rudist biostromes in the upper cretaceous turonian upper santonian limestones of southern istria croatia abstract rudists are well preserved in the upper cretaceous limestones of southern istria where they flourished within different shallow water environments during the turonian to upper santonian in order to determine paleoenvironments a vertical succession of the rich rudist assemblages has been investigated and described within sequence stratigraphy framework the turonian to upper santonian sediments of southern istria in the sense of sequence stratigraphy comprise one complete third order sequence and the beginning of the transgressive systems track tst of the next sequence lower turonian pelagic limestones were deposited on a foundered carbonate platform and represent the beginning of the tst limestones of the late tst lowstand systems track lst were deposited on the inner shelf and the early tst of the next sequence was deposited on the outer shelf all the rudists which appeared after the early turonian disappearance and partial extinction were elevators the genera durania and praeradiolites thrived in bouquets which may coalesce to form thickets in inner shelf environments of the late tst lst their growth depended completely durania or partly praeradiolites on net sediment accumulation the environment in which durania and praeradiolites thrived was subtidal and deep enough to be out of reach of emersion within the same depositional environment these genera were later replaced vertically by radiolites individuals with slim cylindrical shells and wide growth lamellae have full contact within the thickets in which their growth depended little if at all on net sedimentation rate also radiolites occupied the shallower parts of the subtidal zone with a commissure rim rising above the sediment surface renewed deepening in the late santonian resulted in the outer shelf environment of the next tst gorjanovicia together with rare vaccinites flourished after the radiolites gorjanovicia differed from radiolites only in possessing more pronounced vertical ribs in their slightly deeper subtidal environment with pelagic influxes gorjanovicia thrived in bouquets loosely packed gorjanovicia gave vaccinites an opportunity to grow among them the environmental setting of the southern istria rudist biostromes and their correlation with other shallow water deposits in the mediterranean region suggests that a sequence stratigraphy approach can be applied to correlate rudist biostratigraphy on a regional or even inter regional scale

orogenic evolution of the external dinarides in the ne adriatic region a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates abstract mesozoic to cenozoic evolution of the central part of the adriatic plate external dinarides and adriatic foreland is still a matter of debate this is expressed by opposing paleogeographic models single carbonate platform adriatic or adriatic dinaridic versus two carbonate platforms adriatic and dinaridic separated by the inter platform budva cukali basin estimates of shortening during adria ne subduction that resulted in the development of the dinaric alps differ substantially the single platform model involves minor shortening achieved by folding and faulting along steep reverse faults the two platform model involves significant shortening achieved mainly by thrust stacking which resulted in almost complete underthrusting of the intervening basinal deposits analysis of upper cretaceous to paleogene stratigraphical data from both outcrops and boreholes allows regional correlation and the interpretation of major lithostratigraphic units as a result a few tectonostratigraphic units are recognized the tectonostratigraphy is used as a basis for a new model on the late mesozoic to cenozoic evolution of the region generally adriatic and dinaridic segments acted as major regional crustal entities of adria the upper portions of the sedimentary cover were differentially affected by progressive southwestward verging thin skinned deformations during the paleocene to eocene miocene the adriatic foreland stayed out of the deformations and is characterized predominantly by wrench and salt tectonics the regional tectonic map shows arcuate thrust fronts of the external dinarides they could be a consequence of both differential propagation of early orogenic thin skinned deformations over crustal fragments separated by transversal faults and or differential isostatic movements of the fragments the collision zone of the adriatic and dinaridic segments is characterized by late orogenic oligocene to miocene thick skinned compressional uplift exhumation related gravity gliding and still active escape tectonics wrenching these processes masked primary thin skinned deformations a significant amount of shortening within and between the thin skinned sedimentary covers is proposed therefore the question of the general paleogeography of the region and the original nw extent of the budva cukali basin ne adriatic trough remains open

the cenomanian turonian oceanic anoxic event ii palaeoceanographic controls on organic matter production and preservation correlation of the 13c spike with the well dated occurrences of strata rich in organic carbon detailed in schlanger et al this volume indicates that a global episode of intense organic carbon orgc burial took place during the latest cenomanian earliest turonian oceanic anoxic event oae a plenus through i labiatus macrofossil zones and upper r cushmani trz through w archecretacea prz foraminiferal zones over a period of no more than 1 million years m y the shape of the 13c curve indicates that rates of orgc burial gradually increased in the early part of the late cenomanian increased more rapidly in the later cenomanian and levelled off at peak values in latest cenomanian early turonian time during the maximum rate of orgc burial the 13c values decreased nearly to pre late cenomanian levels in the early to middle turonian the decrease in 13c reflects decreasing rates of orgc burial following the cenomanian turonian oceanic anoxic event as well as the probable oxidation and return of significant amounts of orgc to the oceans following regression and re oxygenation of much of the deeper water masses in contact with the seafloor

the stratigraphic and palaeogeographic setting of the late cenomanian anoxic event the late cenomanian carbon isotope excursion can be shown to be synchronous over most areas of the globe where micropalaeontological data are adequate the sedimentological variations seen in these different areas are thought to be due to palaeobathymetry the relationship between this anoxic event and the major faunal change in the late cenomanian is described

the tectonic development of the northern adriatic region constrained by jurassic and cretaceous paleomagnetic results abstract in the northern adriatic region there is a clear boundary between the weakly deformed stable core of the adriatic microplate and its tectonically complicated ne margin the external dinarides which are further subdivided on stratigraphic and structural grounds although most authors distinguish an adriatic and a dinaridic realm within the external dinarides the relationship and the present boundary between the realms are matters of discussion the aim of this study was to obtain paleomagnetic directions from different parts of the northern adriatic segment of the external dinarides and discuss their bearing on the different types of the tectonic models for this purpose we carried out standard paleomagnetic measurements on biostratigraphically well controlled samples from 28 localities from the adriatic mainland and the northern adriatic islands and from one middle jurassic locality representing the stable core of the adriatic microplate in addition six localities from the northern adriatic islands earlier studied paleomagnetically were biostratigraphically updated and thus included in the data set for the northern adriatic islands an albian d i 333 48 k 44 95 9 and a cenomanian santonian d i 334 46 k 188 95 5 paleomagnetic direction was defined they are in perfect agreement with coeval paleomagnetic directions from stable adria thus the paleomagnetic data clearly support the models which conceive the area as the imbricated margin of the adriatic microplate the early d i 338 49 k 118 95 11 the middle d i 342 54 k 112 95 7 and the late d i 336 42 k 62 95 16 jurassic paleomagnetic directions all representing the tectonic units of the adriatic mainland suggest an about 30 cw rotation of this belt of the external dinarides with respect to stable adria the difference can be interpreted as inherited from the differencial rotations of two independent carbonate platforms an adriatic and a dinaric alternatively thrusting of the more internal belt of the external dinarides above the adriaticum may be responsible for the difference

latitudinally different responses of tethyan shoal water carbonate systems to the early aptian oceanic anoxic event oae 1a ocean wide anoxic events represent intensively investigated anomalies in the global carbon cycle most previous research has focussed on hemipelagic and pelagic settings and on the relationship between black shale deposition and carbon isotope excursions the study of ocean wide anoxic events and coeval shallow water settings is now increasingly seen as an interesting complementary approach but one that is not without problems whereas platform drowning characterizes the early aptian of the northern tethyan margin lithocodium bacinella rich facies and ongoing shoal water sedimentation at the southern tethyan margin oman bears important information on potential causes of carbon cycle perturbations the present paper seeks to test the supra regional relevance of the oman data by investigating coeval central tethyan limestones three lower aptian shoal water sections in istria croatia deposited on the isolated adriatic carbonate platform are investigated applying chemostratigraphy carbon and strontium and detailed sedimentological analysis the focus is on peritidal to lagoonal facies characterized by mass occurrences of lithocodium bacinella an enigmatic microencruster community lithocodium bacinella facies occurs predominantly in layers ranging from one to several centimetres in stratigraphic thickness with several layers merging to metre thick packages growth fabrics within the layers include oncoidal morphotypes lumps interconnected patches and columns layers and rare nodular to massive bindstone facies these growth patterns show a remarkable regional extent and consistency over study sites distributed several kilometres apart this widespread distribution suggests that specific lithocodium bacinella morphotypes might serve as regional stratigraphic markers the high resolution carbon isotope chemostratigraphy presented here is based on pristine rudist shells and matrix micrite samples and calibrated against strontium isotope data obtained from screened rudist low mg calcite the chemostratigraphic data are consistent with existing biostratigraphic data and place the studied strata at the onset of early aptian oceanic anoxic event 1a moreover results indicate the near coeval nature of lithocodium bacinella bloom facies in istria and oman the outcomes of this study point to latitudinally different responses of tethyan shoal water carbonate systems platform drowning versus lithocodium bacinella blooms to the ocean wide anoxic event 1a

the biotic response to the late cenomanian oceanic anoxic event integrated evidence from dover se england the late cenomanian sea level rise was coupled with an expansion of the oxygen minimum zone the position of its upper surface may be discerned from the sequential effects on the benthonic and planktonic biota

evolution of the adriatic carbonate platform palaeogeography main events and depositional dynamics abstract the adriatic carbonate platform adcp is one of the largest mesozoic carbonate platforms of the perimediterranean region its deposits comprise a major part of the entire carbonate succession of the croatian karst external or outer dinarides which is very thick in places more than 8000 m and ranges in age from the middle permian or even upper carboniferous to the eocene however only deposits ranging from the top of the lower jurassic toarcian to the top of the cretaceous can be attributed to the adcp defined as an isolated palaeogeographical entity although the entire carbonate succession of the karst dinarides was deposited within carbonate platform environments there were different types of carbonate platforms located in different palaeogeographical settings carboniferous to middle triassic mixed siliciclastic carbonate deposits were accumulated along the gondwanian margin on a spacious epeiric carbonate platform after tectonic activity culminating by regional middle triassic volcanism recorded throughout adria the african promontory a huge isolated carbonate southern tethyan megaplatform abbreviated as stm was formed with the area of the future adcp located in its inner part tectonic disintegration of the megaplatform during the middle to late early jurassic resulted in the establishment of several carbonate platforms including the adriatic apenninic and apulian separated by newly drowned deeper marine areas including the adriatic basin as a connection between the ionian and belluno basins lagonero basin and the area of the slovenian and bosnian troughs the adcp was characterised by predominantly shallow marine deposition although short or long periods of emergence were numerous as a consequence of the interaction of synsedimentary tectonics and eustatic changes also several events of temporary platform drowning were recorded especially in the late cretaceous when synsedimentary tectonics became stronger leading up to the final disintegration of the adcp the thickness of deposits formed during the 125 my of the adcp s existence is variable between 3500 and 5000 m the end of adcp deposition was marked by regional emergence between the cretaceous and the palaeogene deposition during the palaeogene was mainly controlled by intense synsedimentary tectonic deformation of the former platform area some carbonates mostly eocene in age were deposited on irregular ramp type carbonate platforms surrounding newly formed flysch basins and the final uplift of the dinarides reached its maximum in the oligocene miocene the adriatic carbonate platform represents a part although a relatively large and well preserved one of the broader shallow water carbonate platform that extended from ne italy to turkey although its continuity is somewhat debatable in the area near albanian greece boundary this large carbonate body which was deformed mostly in the cenozoic including a significant reduction of its width needs a specific name and the central mediterranean carbonate platform is proposed abbreviated to cmcp although the local names such as adcp for its nw part should be kept to enable easier communication and to facilitate description of local differences in platform evolution

the cenomanian turonian oceanic anoxic event i stratigraphy and distribution of organic carbon rich beds and the marine δ13c excursion marine strata deposited during late cenomanian and early turonian time display lithological faunal and geochemical characteristics which indicate that significant parts of the world ocean were periodically oxygen deficient at or very close to the cenomanian turonian boundary between 90 5 and 91 5ma ago oxygen deficiencies were particularly marked over a period of 1ma this short lived episode of oceanic oxygen deficiency has been termed the cenomanian turonian oceanic anoxic event oae the widespread distribution of anoxic sediments deposited synchronously during such a short lived event indicates that such sediments are not simply the product of coincidental local climatic or basinal water mass characteristics but are the result of a global expansion and intensification of the cenomanian turonian oxygen minimum zone related to feedback between sea level rise and regional palaeoceanography the palaeoceanography of the cenomanian turonian oae is discussed in detail in a companion paper by arthur et al 1987 from authors

impact of cretaceous sea level rise and anoxic events on the mesozoic carbonate platform of yugoslavia the adriatic dinaric carbonate platform of yugoslavia was influenced by rapid sea level rise and an oceanic anoxic event during the cenomanian turonian open marine biota such as planktonic foraminifera radiolarians and locally even ammonites associated with and bracketed by successions of typical shallow water carbonates indicate partial drowning of substantial areas of the platform during this time suggestive furthermore that the rate of increase of water depth was locally great enough to outpace carbonate production the presence of carbon rich and fish bearing platy limestones commonly cherty as an associated coeval facies indicates the development of anoxic or euxinic environments and the stromatolitic laminations in such rocks are attributed to the action of bacterial mats it is suggested that an extensive column of deoxygenated water developed in the neighboring marche umbrian adriatic deep water basin and was carried on to the carbonate platform during the cenomanian turonian transgression

new stepping stones dugi otok and vis islands in the systematic paleomagnetic study of the adriatic region and their significance in evaluations of existing tectonic models abstract the external dinarides from which several conflicting tectonic models were published are the more tectonized ne margin of autochthonous adria dugi otok and vis islands belong to this margin from the two islands a new paleomagnetic study is presented based on 48 geographically distributed and biostratigraphically controlled cretaceous carbonate sediment localities the results suggest that the two islands certainly moved in co ordination after the mid albian which was the time of resumed sedimentation after a period of emersion although some relative movement could have occurred earlier the new post aptian paleomagnetic results are in perfect agreement with recently published paleomagnetic results from stable adria and from the more northerly adriatic islands this consistency suggests that all these areas moved together from the albian on while the coastal range of the external dinarides seems to have moved independently thus autochthonous adria together with the adriatic islands is established as a crustal block within the central mediterranean region which rotated significantly in ccw sense in post cretaceous times

species richness and abundance patterns of tethyan cretaceous rudist bivalves mollusca hippuritacea in the central eastern mediterranean and middle east analysed from a palaeontological database abstract data about the stratigraphical and regional distribution of cretaceous rudist bivalves in the central eastern mediterranean and middle east from the barremian to the maastrichtian have been compiled in a taxonomic databank system the investigated region comprises northern central and southern regions of the cretaceous tethys the regionally different quality of taxonomic data is critically discussed both species richness and abundance number of species records peak in the early aptian late cenomanian and early campanian temporal patterns in species richness are examined in relation to evolutionary innovations of the group crises in species richness and abundance during the early and mid cretaceous were coeval with oceanic anoxia associated with platform drowning also regional emergence affected large parts of the apulian plate and other central tethyan carbonate platforms during the mid cretaceous period of globally high sea level so that these crises can be attributed to regional environmental perturbations induced by either oceanic anoxia or tectonic movements the cenomanian turonian transition marks an important faunal turnover as indicated by the demise of taxonomic groups which are characterised by recumbent ecological morphotypes and predominantly aragonitic shells during the turonian they were replaced by associations dominated by largely calcitic radiolitidae and hippuritidae among which elevator morphotypes dominated the stratigraphy of many post turonian deposits in the studied region is too imprecise for a detailed analysis of late cretaceous distributional patterns and the demise of rudists during the maastrichtian in particular the regional pattern of species richness and abundance is similar throughout most of the investigated region a notable exception is the broad north eastern african shelf from libya to lebanon where rudists were almost completely absent after the coniacian this coincided with shallow water phosphorite and black shale formation on the extended shelf of this region indicating the upwelling of nutrient rich waters and stagnant conditions during this time campanian maastrichtian species rich associations thrived along the north eastern afro arabian margin now exposed in south eastern turkey iran the united arab emirates uae and oman this region forms the single distinct faunal province during the cretaceous in the studied region as indicated by an endemism of 40 at the genus level the low species richness and abundance of hippuritidae on turonian maastrichtian central tethyan carbonate platforms when compared with regions having mixed calcareous siliciclastic sedimentation is interpreted to argue against a widespread photosymbiosis in the group several aspects of this study highlight the importance of regional tectonic and oceanographic controls of distributional and perhaps also evolutionary patterns of rudist bivalves their delineation still suffers from the regionally different quality of stratigraphical and taxonomic data

heavy oil reservoir characterization using elastic wave properties this case history describes seismic monitoring efforts at pikes peak field a prolific heavy oil field production exceeding 42 million barrels just east of the alberta saskatchewan border that has been operated by husky energy since 1981