mesozoic and cenozoic deformation inferred from seismic stratigraphy in the southwestern intracontinental palmyride fold thrust belt syria this paper was published in the geological society of america bulletin the geological society of america retains the copyright to this paper geological society of america p o box 9140 boulder co 80301 9140 usa see also http www geosociety org http atlas geo cornell edu syria chaimov gsa bull 1992 html

late cretaceous sea level changes in tunisia a multi disciplinary approach a multi disciplinary study of sea level and climate proxies including bulk rock and clay mineral compositions carbon isotopes total organic carbon toc sr ca ratios and macro and microfaunal associations reveals seven major sea level regressions in the southwestern tethys during the last 10 million years of the cretaceous late campanian c 74 2 ma 73 4 72 5 ma and 72 2 71 7 ma early maastrichtian 70 7 70 3 ma 69 6 69 3 ma and 68 9 68 3 ma and late maastrichtian 65 45 65 3 ma low sea levels are generally associated with increased terrigenous influx low kaolinite chlorite mica ratios high toc and high sr ca ratios whereas high sea levels are generally associated with the reverse conditions these sea level changes may be interpreted as eustatic as suggested by the global recognition of at least four of the seven major regressions identified 74 2 ma 70 7 70 3 ma 68 9 68 3 ma and 65 45 65 3 ma climatic changes inferred from clay mineral contents correlate with sea level changes warm or humid climates accompany high sea levels and cooler or arid climates generally accompany low sea levels

tertiary of the arabian gulf sedimentology and hydrocarbon potential abstract the paleogene neogene paleogeography of the arabian basin shows a change from the basic continuation of the mesozoic pattern during the paleogene to a new pattern of sedimentation established during the neogene and resulting from movements in the zagros the paleogene shallow water carbonate dominated lithologies in eastern arabia were replaced by deep water neogene carbonates near the zagros and mixed carbonate and clastics in the northern arabian gulf the hydrocarbon potential of these rocks except locally is low and the decreasing amplitude and frequency of faulted and folded structures away from the zagros front suggests that the discovery of fields in structures such as those in iraq iran is low this poverty may however suggest that the untapped potential of the mesozoic rocks may still be high

distribution and preservation of black carbon in the east china sea sediments perspectives on carbon cycling at continental margins abstract we determined the concentrations and radiocarbon 14 c compositions of black carbon bc in the sediments of the east china sea ecs the bc concentrations which were in the range of 0 30 1 52 mg g accounted for 12 65 of the total organic carbon toc the distribution of bc in ecs sediments was controlled by factors such as grain size distance from the coast and deposition rate radiocarbon measurements of bc yielded ages of 6350 10 440 years before present bp suggesting that the percentage of bc derived from biomass combustion was in the range of 29 48 the bc burial flux in sediments of the ecs was estimated to be 1 39 10 6 t yr which was similar to burial fluxes reported for shelf sediments in other areas however the magnitude of the total bc sink was far greater than that of any other shelf regions studied to date indicating the global importance of bc accumulation in the ecs and the magnitude of bc input from large rivers e g the changjiang the riverine delivery of bc to the ecs 73 was far greater than that of atmospheric flux 27 further study of the bc cycle and the interactions of bc with other organic compounds in marginal seas was required to better understand the role of bc in the global carbon cycle

net sediment transport patterns over the bohai strait based on grain size trend analysis grain size trend analysis indicates two distinct characteristics of sediment transport in bohai strait eastward transport dominates the western area and along the coast of the shangdong peninsula this result supports the previous work which indicated that the yellow river sediments are transported from the bohai sea to the yellow sea through the south channel of bohai strait and dispersed into the southern yellow sea along the coast of shangdong peninsula in the central eastern bohai strait net deposition is taking place as indicated by the convergence of the grain size trends this result is consistent with current circulation pattern on bohai strait and the interpretation of strata disclosed by seismic reflection profile this study supports the use of grain size trend analysis for large scale areas on the continental shelf

the chicxulub asteroid impact and mass extinction at the cretaceous paleogene boundary the cretaceous paleogene boundary similar to 65 5 million years ago marks one of the three largest mass extinctions in the past 500 million years the extinction event coincided with a large asteroid impact at chicxulub mexico and occurred within the time of deccan flood basalt volcanism in india here we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction notably a single ejecta rich deposit compositionally linked to the chicxulub impact is globally distributed at the cretaceous paleogene boundary the temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations for example darkness and cooling lead us to conclude that the chicxulub impact triggered the mass extinction

the cretaceous paleogene boundary in jordan abstract the cretaceous paleogene k pg boundary in jordan is marked by a major depositional hiatus that differs in magnitude from place to place due to variable structural movements of the syrian arc fold belt that resulted in irregularity of jordan levant depositional basin after the deposition of maastrichtian succession to elucidate the nature of this hiatus fieldwork was carried out at a number of locations including lithofacies and stratigraphic analysis and a multi proxy study of microplanktonic biostratigraphy calcareous nannofossilis and planktonic formaminifera however the duration of this hiatus extended over latest maastrichtian and early danian stages this is based on the absence of the planktonic foraminifera pseudoguembelina hariaensis cf3 pseudoguembelina palpebra cf2 plummerita hantkeninoides cf1 guembelitria cretacea p0 parvularugoglobigerina eugubina p zones and parasubbotina pseudobulloides p1a subzones and the coeval calcareous nannofossils nephrolithus frequens and markalius inversus zones we estimate that in the paleo lows areas an unexpected 3 96 ma hiatus is present conversely in swell areas the duration of the hiatus represents the entire danian selandian interval and revealed an unexpected 10 33 ma hiatus especially in the central part of jordan subsequently a marked transgression took place over the whole of jordan which resulted in the prevalence of deep water conditions zones p4 or equivalent np7 8 this caused the deposition of a retrogradational parasequence set of middle shelf pelagic marl and chalk during a rapid relative rise of sea level a correlative hiatus and time gap have also been reported in different parts of the arabian and african plates indicating that jordan was influenced by regional tectonics that combined with the latest maastrichtian sea level fall resulted in a long term sub marine hiatus and or non deposition of sediments a combination of sea level changes and tectonic uplift are the likely cause for such a long gap in the sediment record in the region

late cretaceous ca 84 ma compressive deformation of the stable platform of northeast africa egypt far field stress effects of the santonian event and origin of the syrian arc deformation belt large scale northeast trending asymmetric folds and associated contractional faults seismically induced slump structures and strike slip and extensional faults of santonian age occur within the eastern desert of egypt 150 km south of the syrian arc mobile belt the region also displays a locally developed angular unconformity at the base of the flat lying campanian limestone these features demonstrate that the deformation event responsible for the syrian arc also led to northwest southeast shortening in central egypt ca 84 ma the late santonian shortening corresponds precisely with a brief period of compression that swept across the entire african plate coeval with a significant change in the poles of opening of the north atlantic this santonian event is a prominent example of the role that far field compressional stresses can play in stable intraplate settings

flux and fate of yangtze river sediment delivered to the east china sea numerous cores and dating show the yangtze river has accumulated about 1 16 x 10 12 t sediment in its delta plain and proximal subaqueous delta during holocene high resolution seismic profiling and coring in the southern east china sea during 2003 and 2004 cruises has revealed an elongated similar to 800 km distal subaqueous mud wedge extending from the yangtze river mouth southward off the zhejiang and fujian coasts into the taiwan strait overlying what appears to be a transgressive sand layer this distal clinoform thins offshore from similar to 40 in thickness between the 20 and 30 m water depth to 1 2 in between 60 and 90 m water depth corresponding to an across shelf distance of less than 100 km total volume of this distal mud wedge is about 4 5 x 10 11 m 3 equivalent to similar to 5 4 x 10 11 t of sediment most of the sediment in this mud wedge comes from the yangtze river with some input presumably coming from local smaller rivers thus the total yangtze derived sediments accumulated in its deltaic system and east china sea inner shelf have amounted to about 1 7 x 10 12 t preliminary analyses suggest this longshore and across shelf transported clinoform mainly formed in the past 7000 yrs after postglacial sea level reached its mid holocene highstand and after re intensification of the chinese longshore current system sedimentation accumulation apparently increased around 2000 yrs bp reflecting the evolution of the yangtze estuary and increased land erosion due to human activities such as fanning and deforestation the southward flowing china coastal current the northward flowing taiwan warm current and the kuroshio current appear to have played critical roles in transporting and trapping most of yangtze derived materials in the inner shelf and hence preventing the sediment escape into the deep ocean c 2006 elsevier b v all rights reserved

comparison of quantification methods to measure fire derived black elemental carbon in soils and sediments using reference materials from soil water sediment and the atmosphere black carbon bc the product of incomplete combustion of fossil fuels and biomass called elemental carbon ec in atmospheric sciences was quantified in 12 different materials by 17 laboratories from different disciplines using seven different methods the materials were divided into three classes 1 potentially interfering materials 2 laboratory produced bc rich materials and 3 bc containing environmental matrices from soil water sediment and atmosphere this is the first comprehensive intercomparison of this type multimethod multilab and multisample focusing mainly on methods used for soil and sediment bc studies results for the potentially interfering materials which by definition contained no fire derived organic carbon highlighted situations where individual methods may overestimate bc concentrations results for the bc rich materials one soot and two chars showed that some of the methods identified most of the carbon in all three materials as bc whereas other methods identified only soot carbon as bc the different methods also gave widely different bc contents for the environmental matrices however these variations could be understood in the light of the findings for the other two groups of materials i e that some methods incorrectly identify non bc carbon as bc and that the detection efficiency of each technique varies across the bc continuum we found that atmospheric bc quantification methods are not ideal for soil and sediment studies as in their methodology these incorporate the definition of bc as light absorbing material irrespective of its origin leading to biases when applied to terrestrial and sedimentary materials this study shows that any attempt to merge data generated via different methods must consider the different operationally defined analytical windows of the bc continuum detected by each technique as well as the limitations and potential biases of each technique a major goal of this ring trial was to provide a basis on which to choose between the different bc quantification methods in soil and sediment studies in this paper we summarize the advantages and disadvantages of each method in future studies we strongly recommend the evaluation of all methods analyzing for bc in soils and sediments against the set of bc reference materials analyzed here

seismic reflection imaging of a geothermal aquifer in an urban setting a seismic reflection survey that was conducted in downtown boise idaho to help city planners site a new well for injection of spent geothermal water illustrates some methods to safely and successfully employ a seismic reflection survey in an urban setting the objective of the seismic survey was to estimate the depth and continuity of a basalt and rhyolite volcanic sequence well siting was based on geothermal aquifer depth location of interpreted faults projected thermal impact of injection on existing wells surface pipe extension costs and public land availability seismic acquisition tests and careful processing were used to ensure high quality data while minimizing the potential for damage along city streets a video camera placed in a sewer and a blast vibration monitor were used to confirm that energy from the seismic source a 75 in3 land air gun did not damage nearby buildings street surfaces or buried utilities along the survey lines walkaway seismic tests were also used to compare sign

origin of the extreme polymetallic enrichment cd cr mo ni u v zn of the late cretaceous early tertiary belqa group central jordan abstract the sedimentary formations of the late cretaceous to early tertiary belqa group correspond to pure to slightly clayey limestones and minor black shales characterized by a remarkable enrichment in phosphorous and various redox sensitive elements cd cr mo ni u v zn phosphorous enrichment is related to the great phosphorite deposition event that has occurred at the southern margin of the tethys ocean during this period the very low organic matter contents in the limestones despite their strong enrichment in redox sensitive elements is attributed to a deposition in anoxic water but under shallow water conditions permitting the bacterial degradation of a large part of the organic matter most of the elements constituting the belqa group sediments have been deposited from the sea water either directly by chemical precipitation most ca and redox sensitive elements or indirectly through biogenic activity p part of ca and u except for the minor detritial contribution presents in some limestones and more significantly in the shales such an origin is also supported by the ree patterns of the limestones which are similar to that of the present sea water the anomalously high concentrations of some redox sensitive trace metals cr ni and probably cd compared to worldwide black shales is explained by an exogenic metal flux corresponding to the leaching of the huge amounts of ophiolites obducted during the collision between the african arabian and eurasian plates at the same time as the deposition of the belqa group sediments uranium is substituted for calcium in biogenic apatite in the limestones but was also directly precipitated from sea water in the black shales in relation with the suboxic environment with the periodic anoxia developed during their deposition in restricted deeper basins the pyrometamorphism resulting from the burning of organic rich levels in clayey limestones has created a further enrichment of redox sensitive elements in the resulting marbles by a volume loss resulting from decarbonatation reactions and the combustion of the organic matter

guembelitria dominated late maastrichtian planktic foraminiferal assemblages mimic early danian in central egypt abstract during the late maastrichtian 66 8 65 5 ma the asyut basin in central egypt experienced a breakdown of the surface to bottom gradient of the 13c 12c ratio with planktic 13c values 0 2 0 8 lighter than benthic values planktic foraminiferal species diversity was reduced by more than 50 with assemblages dominated 60 90 by the opportunistic blooms of the disaster species guembelitria cretacea which mimic the early danian the prolonged breakdown in productivity occurred during a time of tectonic activity and increased terrestrial runoff that may have resulted in highly eutrophic waters coupled with a sea level regression 65 5 ma that led to restricted circulation increased productivity during the short climate warming between 65 4 and 65 2 ma is associated with increased species diversity abundant rugoglobigerinids and common heterohelicids at the end of the maastrichtian decreased productivity coincided with the k t impact and mass extinction followed by characteristically early danian low diversity assemblages the similarity of the late maastrichtian and post k t impact guembelitria dominated assemblages reveals that the planktic foraminiferal response to the k t catastrophe was not unique but followed a predictable pattern of response to severe environmental perturbations

carbonate ramp depositional systems abstract the classification tectonic settings stratigraphy and early diagenesis of carbonate ramp systems are reviewed carbonate ramps are common in all geological periods but were dominant at times when reef constructing organisms were absent or inhibited ramps can be subdivided into inner mid and outer ramp environments the mid ramp zone extends from fair weather wave base to normal storm wave base although the water depths which these boundaries represent vary an additional outer slope environment occurs on distally steepened ramps as with siliciclastic shelves a range of wave storm and tide dominated ramps can be recognised and this forms the most convenient basis for ramp classification the carbonate productivity profile of ramps differs from that of rimmed shelves with the inner ramp showing lower production rates than comparable shallow water facies on rimmed shelves the zone of greatest organic carbonate sediment production appears to have shifted from the mid ramp to the inner ramp since the late jurassic carbonate ramps occur in most types of sedimentary basin but are best developed where subsidence is flexural and gradients are slight over large areas as in foreland and cratonic interior basins and along passive margins the featureless depositional profiles of many ramps means that sequence geometries are best observed on regional seismic lines some show low angle sigmoidal or shingled clinoforms suggesting that ramps may seldom be homoclinal but possess subtle slope geometries which reflect depositional environments because of their low angle slopes ramps respond differently to rimmed shelves during relative sea level changes although results seem to be strongly dependent on the rate of relative sea level change during a minor fall shallow ramp facies belts will simply shift basinwards in a forced regression in contrast the whole surface of a steep sloped flat topped rimmed shelf may be exposed so that sediment production ceases or is drastically reduced during a major fall shallow ramp bounded basins may empty completely conversely ramps also flood gradually whereas rimmed shelves do so more rapidly homoclinal ramps develop no resedimented lowstand deposits rimmed shelves and distally steepened ramps in contrast may develop lowstand talus or turbiditic wedges distally steepened ramps may behave more like homoclinal ramps during minor base level falls and like rimmed shelves during major base level falls many ramps consist of layered successions of several ramp sequences stacked one upon the other ramp stacks of this sort may show gross vertical accretion but individual ramp sequences seldom appear to develop in a keep up style apart from minor organic buildups as with many rimmed shelves steepening of the outer ramp margin due to tectonism slope inheritance or differential sedimentation may promote the development of a distally steepened ramp or rimmed shelf a wide variety of organisms have constructed buildups in mid and outer ramp environments isolated buildups may seed early in ramp development accrete to wave base or sea level and continue growth by stacking through successive ramp sequences so that depositional and diagenetic features within them are in concert with those of the shallow ramp the location of isolated buildups on ramps is governed by tectonism halokinesis antecedent topography or by the subtle slope geometry of the previous ramp sequence diagenesis on ramps shows some major variations compared with diagenesis on steep sloped flat topped carbonate platforms ramp bounded basins may form prolific petroleum sourcing and reservoiring systems and offer a range of subtle stratigraphic play types and lateral facies variations which determine reservoir quality and distribution isolated buildups in the mid and outer ramp environments represent one of the commonest petroleum reservoirs in ramp systems and tend to have their foundations in transgressive systems tracts grainstone and packstone reservoirs are widespread and range from shoreline carbonate sandbodies to major detached shoal complexes or shoals over offshore highs grainstone sandbodies occur in both highstand systems tracts and in prograding lowstand wedges

palaeoenvironmental changes across the danian selandian boundary in the north sea basin abstract the danian selandian boundary 60 ma marks the cessation of 40 million years of carbonate deposition in the north sea basin and a shift to siliciclastic deposition on the basis of variations in lithology benthic and planktonic foraminifera and calcareous nannofossils in three cores from storebaelt in the eastern part of the north sea basin we have reconstructed the palaeoenvironmental changes across the boundary the benthic foraminiferal faunas belong to the midway type fauna they are extremely rich and more than 260 taxa have been recognized q mode cluster analysis groups the benthic assemblages into four biofacies which correspond fairly closely to lithological units correlation of the storebaelt records with marine palaeorecords from the danish basin and the north sea basin indicate that the transformation of the north sea from a carbonate to a siliciclastic basin occurred in four steps separated by relatively long stable periods the most important external factors involved in the change are firstly a drop in the relative sea level during the late danian leading to the disappearance of bryozoans from the north sea basin and to non deposition and erosion in many areas secondly coinciding with the danian selandian boundary an uplift of the scotland shetland area resulting in a massive input of siliciclastic deposits to the north sea basin thirdly during the early selandian inversion of the sorgenfrei tornquist zone and mesozoic basins in the southern and eastern part of the north sea basin resulted in a huge influx of reworked cretaceous chalk and an almost complete stop of carbonate production finally later in the early selandian in connection to a general sea level rise and a reduction in the gateway between the north sea basin and the tethys sea the sea bottom conditions became colder and more acidic this resulted in partial dissolution of the carbonates and the deposition shifted from marl to clay comparison with records from the western pyrenees the nile basin and the eastern north america suggests that sea level changes across the danian selandian boundary are primarily of eustatic nature

application of pmf receptor model merging with pahs signatures for source apportionment of black carbon in the continental shelf surface sediments of the bohai and yellow seas china black carbon bc and polycyclic aromatic hydrocarbons pahs are byproducts generated from the incomplete combustion of organic materials including fossil fuels and biomass the similar production processes shared by bc and pahs provide the possibility to infer the bc sources using the pahs signatures this study successfully utilized data sets of bc and pahs analyzed from the continental shelf surface sediments of the bohai and yellow seas to a standard receptor model of positive matrix factorization pmf to apportion the sources of bc in the sediment matrix results showed that combustion of fossil fuels i e coal and oil petroleum accounted for an average level of 83 5 of the total bc preserved which was significantly higher than that from the biomass burning 17 5 the spatial distributions of the fossil bc concentrations and percentages differed significantly from those of the biomass bc implying their different geochemical behaviors in the continental shelf regimes and further emphasizing the importance to effectively differentiate between fossil bc and biomass bc in addition to the relative proportions of the bc subtypes char bc soot bc the regional specific hydrodynamic conditions including the cold cyclonic eddy resuspension and coastal current also exerted a significant influence on these spatial variations

eocene and early oligocene micropaleontology and paleoenvironments in se umbria italy a detailed study based on calcareous nannofossils and planktonic and benthic foraminifera has been carried out on five sections in the scaglia group of the umbrian region visso and cascia areas central italy these sections are characterized by continuous pelagic sedimentation and are constituted mainly of marls marly limestones and limestones of early eocene to early oligocene age calcareous turbidites with shallow water skeletal debris discharged from the latium abruzzi carbonate platform are interbedded within the pelagic sequences the biostratigraphic study based on calcareous nannofossils and planktonic foraminifera confirmed the continuous succession of standard events and revealed some new ones these results allow us to refine the biostratigraphic resolution with a very good correlation between calcareous nannofossil and planktonic foraminiferal zonations the major features and events recognized are the early middle eocene boundary zones p9 p10 is characterized by the first occurrence fo of hantkeninids by abundant thick walled globigerinatheka g senni and by spinose acarininids a decrease has been noted in planoconvex morozovellids and an increase of low spired subbotinids the benthic assemblage shows a great variability with an increase in the zone p11 of the large heterolepa and cibicidoides this is an event of worldwide significance in the calcareous nannofossils the fo of nannotetrina sp was used to define the lower boundary of zone cp13 instead of n fulgens because poor preservation prevented identification at the specific level the fo of reticulofenestra umbilica marking the lower boundary of zone cp14 occurs in the upper part of zone p11 the zone p13 was recognized indirectly because of the absence of the index species orbulinoides beckmanni the base of the zone is close to the fo of turborotalia cerroazulensis and is defined by an increase of catapsydrax sp and by the last occurrence lo of acarinina bullbrooki the top of the zone is defined by an increase of the high spired subbotinids of the s corpulenta group and the disappearance of morozovella spinulosa the middle late eocene boundary zones p14 p15 is characterized by the extinction of the spinose acarininids and of the smooth walled planorotalites from zone p13 to zone p15 there is a replacement in the benthic assemblages in fact pleurostomella heterolepa and anomalinoides capitata characterize these zones bolivinids become abundant and uvigerinids appear around the p14 p15 boundary the late eocene is characterized by an increase of subbotinids with abortive chambers and of the turborotalia cerroazulensis lineage hantkeninids and cribohantkeninids are rare particularly c inflata the fo of istmolithus recurvus has been noted at the base of zone p16 within this zone globigerinatheka index and turborotalia cunialensis coexist the lo of g index is associated with a strong decrease of representatives of the genus globigerinatheka at the same level of the lo of g index the coeval extinctions of discoaster barbadiensis and discoaster saipanensis are noted just above this level within zone p17 the lo of t cerroazulensis lineage t cocoaensis and t cunialensis has been recognized the eocene oligocene boundary is defined by planktonic foraminifera at the extinction level of hantkeninids and cribrohantkeninids shortly following that of the t cerroazulensis group

paleogene calcareous nannofossil magnetobiochronology results from south atlantic dsdp site 516 abstract the detailed study of an expanded paleogene section with abundant moderate to well preserved calcareous nannofossils from south atlantic dsdp site 516 has resulted in a precise correlation of most calcareous nannofossil markers with the magnetostratigraphy many nontraditional datums have also been documented and correlated to the magnetostratigraphy comparison of the results from site 516 with those of previous studies from other areas enables a critical evaluation of the accuracy synchroneity or diachroneity of the species events over geographically long distances of special significance is the correlation for the first time of the stratigraphic ranges of chiasmolithus gigas and rhabdosphaera gladius with the magnetostratigraphy other important results include the following first occurrence fo of cruciplacolithus primus 66 3 ma fo chiasmolithus danicus 65 6 66 0 ma fo prinsius martinii 65 5 66 0 ma fo heliolithus kleinpellii 59 8 61 6 ma probably diachronous last occurrence lo of tribrachiatus orthostylus 51 0 54 8 ma unreliable fo chiasmolithus gigas 47 4 ma fo reticulofenestra umbilica 44 6 ma lo chiasmolithus gigas 44 4 46 8 ma diachronous lo nannotetrina fulgens 44 2 ma lo chiasmolithus grandis 40 0 41 6 ma probably diachronous fo chiasmolithus oamaruensis 39 8 40 4 ma unreliable fo isthmolithus recurvus 39 5 ma lo reticulofenestra reticulata 37 6 ma lo discoaster saipanensis 36 4 ma end acme of ericsonia subdisticha diachronous fo and lo sphenolithus distentus unreliable and lo reticulofenestra bisecta 24 0 ma

maastrichtian climate productivity and faunal turnovers in planktic foraminifera in south atlantic dsdp sites 525a and 21 abstract stratigraphic faunal and isotopic analyses of the maastrichtian at dsdp sites 525a and 21 in the south atlantic reveal a planktic foraminiferal fauna characterized by two major events an early late maastrichtian diversification and end maastrichtian mass extinction both events are accompanied by major changes in climate and productivity the diversification event which occurred in two steps between 70 5 and 69 1 ma increased species richness by a total of 43 and coincided with the onset of major cooling in surface and bottom waters and increased surface productivity the onset of the terminal decline in maastrichtian species richness began at 67 5 ma and the first significant decline in surface productivity occurred at 66 2 ma coincident maximum cooling to 13 c in surface waters and the reduction of the surface to deep temperature gradient to less than 5 c major climatic and moderate productivity changes mark the mass extinction and the last 500 kyr of the maastrichtian between 200 and 400 kyr before the k t boundary surface and deep waters warmed rapidly by 3 4 c and cooled again during the last 100 kyr of the maastrichtian surface productivity decreased only moderately across the k t boundary species richness began to decline during the late maastrichtian cooling and by k t boundary time the mass extinction had claimed 66 of the species viewed within the context of maastrichtian climate and productivity changes the k t mass extinction could have resulted from extreme environmental stress even without the addition of an extraterrestrial impact

senonian basin inversion and rejuvenation of rifting in africa and arabia synthesis and implications to plate scale tectonics abstract the late paleozoic to tertiary stratigraphic record of much of the african plate reflects the effects of continental rifting and passive margin development several short lived but widespread and tectonically important compressional or wrench dominated events occurred however during the permian to recent evolution of africa we focus here on the best documented of these events which occurred during the late santonian at that time older sedimentary basins mostly ene wsw trending were folded and inverted including some basins along the tethyan margin from morocco to the syrian arc and the intraplate benue southern chad basins and the lugh mandera basin in oman ophiolites were obducted following the santonian tectonism an extensive phase of rifting occurred in central and north africa and northern arabia spanning from campanian to maastrichtian or paleocene times rejuvenation or acceleration of subsidence occurred in several basins located along the tethyan margin along the atlantic and indian ocean margins as well as within the intraplate domain rifting was sometimes accompanied by magmatic activity especially in offshore northern libya and along the indian ocean margin compressional deformations rejuvenated or developed by latest maastrichtian times along the tethyan margin and locally within the intraplate domain one of the most remarkable attributes of the santonian tectonic event which we consider representative of the major trans african stress field changes is the rapidity with which the change was reflected stratigraphically across north and central africa and its short duration the cause of the santonian compressional event is directly linked to the change in poles of rotation for the opening of the atlantic at 83 85 ma the end of the cretaceous normal magnetic quiet zone this was also synchronous with the obduction of ophiolites along the northeast margin of arabia oman the onset of separation between india and madagascar with formation of the mascarene oceanic basin and the development of the european alpine chain we interpret these phenomena as causally related aspects of a global tectonic event the santonian compressional event as well as the campanian maastrichtian rifting event and the end cretaceous compressional event illustrate the critical connection between intraplate tectonic histories and processes occurring at sometimes very distant plate boundaries

late cretaceous eocene nannofossil and magnetostratigraphic correlations near gubbio italy abstract using a modified sample preparation technique we have been able to establish a detailed lower campanian to upper eocene nannofossil stratigraphy in the bottaccione and contessa highway sections near gubbio appearance and extinction levels of virtually all the commonly used calcareous nannofossil zonal markers have been recognized and can now be closely correlated with the planktonic foraminifera zonation and the magnetic reversal stratigraphy previously established in these sections comparisons with the nannofossil calibrations of the oceanic magnetic anomaly sequence in deep sea drilling project dsdp sites suggest that magmetic subchrons c17n and c25n are missing in the bottaccione section the observed variability of the relative stratigraphic position of most plankton events is confirmed to less than one magnetic subchron absolute abundance paleobiogeographic restriction and differential preservation render some of the traditionally used biostratigraphic events less reliable than others

a review of the tectonics of the northern middle east region the structure of the northern part of the arabian platform is reviewed in the light of hitherto unpublished exploration data and the presently accepted kinematic model of plate motion in the region the palmyra and sinjar zones share a common history of development involving two stages of rifting one in the triassic jurassic and the other during late cretaceous to early tertiary times deformation of the palmyra zone during the mio pliocene is attributed to north south compression on the eastern block of the dead sea transcurrent system which occurred after continental collision in the north in southeast turkey the asymmetry of the palmyra zone is believed to result from northward underthrusting along the southern boundary facilitated by the presence of shallow triassic evaporites an important nw se cross plate shear zone has been identified which can be traced for 600 km and which controls the course of the river euphrates over long distances in syria and iraq transcurrent motion along this zone resulted in the formation of narrow grabens during the late cretaceous which were compressed during the mio pliocene to a large extent present day structures in the region result from compressional reactivation of old lineaments within the arabian plate by the transcurrent motion of the dead sea fault zone and subsequent continental collision

how complete are cretaceous tertiary boundary sections a chronostratigraphic estimate based on graphic correlation cogent interpretations of data bearing on the cretaceous tertiary k t extinction controversy depend on the existence of accurate chronostratigraphic models for the various k t boundary sections we have employed the graphic correlation technique to summarize biostratigraphic and lithostratigraphic data from 15 intensively sampled k t boundary sections within a common chronostratigraphic model our results indicate that almost all of these sections along with 13 additional boundary sections not used to construct the model contain prolonged and in many cases multiple hiatuses of these 28 boundary sections only six were found to contain a continuous record of sediment accumulation across the k t boundary itself these six k t complete sections are el kef tunisia agost spain caravaca spain and three sections along the brazos river texas a comparative analysis of hiatus distributions among these 28 k t boundary sections also reveals the presence of systematic differences between continental shelf and deep sea depositional environments the lower danian interval immediately following the k t boundary and extending into biochronozones p0 and p1a is typically missing from the deep sea whereas boundary sections deposited in shallower middle neritic to upper slope environments are in most cases complete across the k t boundary these shallow neritic boundary sections however are in many instances disrupted by hiatuses at the p0 p1a boundary and again in the upper part of zone p1a these differential patterns of hiatus distribution between deep sea and continental shelf depositional settings appear to be linked to sea level fluctuations our data suggest that the apparently sudden mass extinction of planktonic foraminifera and anomalies in the occurrence of geochemical tracers that are characteristic of the k t boundary in deep sea sections may be artifacts of a temporally incomplete deep sea stratigraphic record

stratigraphy of the middle eocene lower oligocene successions in northwestern and eastern jordan abstract rocks of eocene and oligocene age consisting mainly of carbonate ramp facies are widely distributed in jordan but no previous stratigraphic works have dealt with the eocene oligocene contact stratigraphic analysis based on field exploration and detailed lithostratigrapic and biostratigraphic preliminary data detected a major hiatus that separates the middle eocene lutetian from the early oligocene rupelian in the studied exposures in the wadi el ghadaf and ash shunah areas of jordan our results reveal that the planktonic foraminifera turborotalia cerroazulensis pseudohastigerina spp p18 zone and the calcareous nannoplankton ericsnia subdisticha np21 zone of early oligocene age were recorded immediately above the morozovelloides lehneri e11 zone and the discoaster tanii nodifer np16 zone indicating a period of non deposition as a result of tectonic activity and or sea level changes a correlative hiatus and time gap were also reported in different parts of the arabian and african plates which representing the contemporaneous paleo high areas the presence of the early oligocene shallow marine calcareous planktonic assemblages indicates that shallow shelves of the tethys ocean occupied the paleotopographic lows of jordan with deepening of the depositional basin toward the north

hiatus distributions and mass extinctions at the cretaceous tertiary boundary much disagreement over the interpretation of data bearing on various cretaceous tertiary k t extinction scenarios results from a failure to view these data within their appropriate stratigraphic context combined biostratigraphic and chronostratigraphic analyses of k t boundary sequences have revealed systematic differences in patterns of sediment accumulation within continental shelf and deep sea depositional settings although virtually all deep sea boundary sequences are marked by intervals of nondeposition or hiatus formation during the latest cretaceous and earliest tertiary many continental shelf slope sequences appear to be temporally complete over this same interval this differential pattern of sediment accumulation can be related to the latest maastrichtian earliest danian sea level rise during which deep sea sediment accumulation rates would be expected to drop as the locus of sediment deposition migrated across the continental shelf our data suggest that the abrupt shifts in carbon isotope abundances single peak ir anomalies and apparently instantaneous mass extinctions of marine plankton which are routinely reported from deep sea k t boundary sequences and used to support a causal relation between late cretaceous bolide impacts and k t mass extinctions may be artifacts of a temporally incomplete or extremely condensed deep sea stratigraphic record

role of upper cretaceous oyster bioherms in the deposition and accumulation of high grade phosphorites in central jordan abstract phosphorite grains were authigenically precipitated within precursor marl and biosiliceous deposits during high water level and intense upwelling within the tethys ocean to the north of jordan with falling sea level the oyster lopha villei colonized bathymetric highs in the shallow shelfal environments in east central jordan during the uppermost campanian lower maastrichtian late cretaceous the oyster bioherms in the epeiric southern shelf of the tethys formed small basins several hundreds of meters across and about 40 50 m deep under these lowstand conditions oyster shells were shed off the bioherms and deposited as large cross bedded units on the flanks of the basins at the same time precursor phosphatic sediments were reworked and winnowed to form high grade phosphorite sand more than 250 million metric tons 250 109 kilograms of phosphorite sand were deposited basinward of the oyster beds as sea level continued to fall the oyster bioherms formed partially silled basins with low biological diversity in which marl and or bituminous marl was deposited the marls are overlain by the transgressive phosphatic marl and chalk of the muwaggar formation which were deposited under open marine conditions

sediment transport off the huanghe yellow river delta and in the adjacent bohai sea in winter and seasonal comparison abstract based on the data on the current velocity water temperature salinity turbidity and concentration of suspended sediment collected in november 2006 along three survey transects at three time series ship based stations off the huanghe yellow river delta and at twenty four grid survey stations in the adjacent bohai sea sediment transport off the huanghe delta and in the adjacent bohai sea under winter regime were studied and compared with those from the summer season the homogeneous distribution of salinity temperature and sediment in the water column indicated a well mixed body of water a zone of high suspended sediment concentrations ssc 100 mg l 1 with a width of 35 km was identified along the delta coast two highest ssc centers were found in the surface and middle water layers around the abandoned diaokou huanghe river mouth and the present huanghe river mouth and the third one in the bottom layer around the abandoned qingshuigou huanghe river mouth these three highest ssc centers become major sediment source areas in winter based on the location of the high bottom shear stress zone the prevailing wave directions and the protuberant topography of the river mouths we identified the resuspension origin of the three highest ssc centers caused mostly by the winter storm waves partially by tidal currents suspended sediment flux ssf along the three coastal transects indicated that the sediment in the northwest part of the delta was transported northeastward and southeastward along the coast of the recent delta lobe the ssc and ssf were higher in winter than summer by 1 7 27 1 and 2 122 5 times respectively except around the present river mouth this indicates that the intensity of sediment transport in winter is much stronger than in summer due to the powerful effect of winter storms although the river water and sediment discharges to the sea were much greater in summer the massive huanghe sediment to the sea was accumulated in a narrow coastal area due to weak hydrodynamics in summer and then strongly resuspended mostly by storm waves in winter and transported to the offshore area the coastal area off the huanghe delta acts as a sediment sink in summer and converted to be a sediment source in winter in response to the seasonal variation of the east asian monsoon in this region the erosion accumulation pattern of the huanghe subaqueous delta from 1976 to 2003 illustrates that river laden sediment is deposited mainly in the southern part off the coastal area and it is also the result of intensive southward sediment transport in winter

distribution input pathway and mass inventory of black carbon in sediments of the gulf of thailand se asia the coastal margins around southeast asia se asia may serve as an ideal location to study the source sink process of sedimentary black carbon bc because se asia has been identified as one of the major bc emission source regions in the world this study provides an extensive picture of recent regional scale sedimentary bc sequestration in the gulf of thailand got a tropical marine system in se asia generally the sedimentary bc concentrations 0 07 3 99 mg g were in the low to moderate ranges of those obtained in other coastal sediments around the world regional variability of the bc and its correlation with the sediment grain size and total organic carbon toc content indicated a general hydrodynamic constraint on bc occurrence in the lower gulf in contrast to the upper gulf with a more source dependence due to the direct land based input bc toc values and the varied bc components char and soot as well as their correlations suggested that char was the predominant constituents of sedimentary bc both in the upper and lower gulf which could be mainly derived from biomass burning and entered into the nearshore region through direct fluvial transport and surface run off the estimated bc burial flux similar to 212 mu g cm 2 y and mass inventory similar to 200 gg y in the got on the hundred year timescale were of the same order of magnitude compared with other oceanic margins and thus the tropical shelf sediments from se asia could serve as an important sink of land emitted bc c 2015 elsevier ltd all rights reserved

the sequestration sink of soot black carbon in the northern european shelf sediments 1 to test the hypothesis that ocean margin sediments are a key final repository in the large scale biogeospheric cycling of soot black carbon soot bc an extensive survey was conducted along the 2 000 km stretch of the swedish continental shelf scs the soot bc content in the 120 spatially distributed scs sediments was 0 180 130 26 dw median with interquartile ranges corresponding to 5 of total organic carbon using side scan sonar constraints to estimate the areal fraction of postglacial clay sediments that are accumulation bottoms 15 of scs the soot bc inventory in the scs mixed surface sediment was estimated at 4 000 gg combining this with radiochronological constraints on sediment mass accumulation fluxes the soot bc sink on the scs was 300 gg yr which yielded an area extrapolated estimate for the northern european shelf nes of 1 100 gg yr this sediment soot bc sink is 50 times larger than the river discharge fluxes of soot bc to these coastal waters however of similar magnitude as estimates of atmospheric soot bc emission from the upwind european continent while large uncertainties remain regarding the large scale to global bc cycle this study combines with two previous investigations to suggest that continental shelf sediments are a major final repository of atmospheric soot bc future progress on the soot bc cycle and how it interacts with the full carbon cycle is likely to benefit from14c determinations of the sedimentary soot bc and similar extensive studies of coastal sediment in complementary regimes such as off heavily soot bc producing areas in s and e asia and on the large pan arctic shelf

structure and evolution of the petroliferous euphrates graben system southeast syria the northwest trending euphrates graben system is an aborted intracontinental rift of late cretaceous age that has subsequently been hidden by cenozoic burial approximately 100 km wide the system comprises an extensive network of grabens and half grabens extending some 160 km from the anah graben in western iraq to the palmyride fold belt in central syria where it becomes more subdued the youngest prerift rocks are presently at a maximum depth of about 5 km based primarily on interpretation of 1500 km of seismic reflection profiles and data from 35 wells we mapped a complex network of numerous branching normal and strike slip faults generally striking northwest and west northwest both branched and single strand linear normal faults of generally steep dip as well as positive and negative flower structures are manifest on seismic sections no single rift bounding fault is observed instead a major flexure coupled with minor normal faulting marks the southwestern edge of the basin with considerable variation along strike to the northeast deformation diminishes on the rawda high near the iraqi border the euphrates graben system likely formed in a transtensional regime with active rifting primarily restricted to the senonian and with an estimated maximum extension of about 6 km minor cenozoic inversion of some structures also is evident approximately 30 oil fields have been discovered in the euphrates graben system since 1984 recoverable reserves discovered to date reportedly exceed 1 billion barrels of oil and lesser amounts of gas light oil is primarily found in lower cretaceous sandstone reservoirs juxtaposed by normal faulting against upper cretaceous synrift sources and seals

pan arctic patterns in black carbon sources and fluvial discharges deduced from radiocarbon and pah source apportionment markers in estuarine surface sediments 1 a pan arctic geospatial picture of black carbon bc characteristics was obtained from the seven largest arctic rivers by combining with molecular combustion markers polycyclic aromatic hydrocarbons and radiocarbon 14c analysis the results suggested that the contribution from modern biomass burning to bc ranged from low in the yukon 8 and lena 5 rivers to high in the yenisey river 88 the mackenzie river contributed almost half of the total arctic fluvial bc export of 202 kton a 1 kton 109 g with the five russian arctic rivers contributing 10 36 kton a 1 each the 14c based source estimate of fluvially exported bc to the arctic ocean weighted by the riverine bc fluxes amount to about 20 from vegetation biofuel burning and 80 from 14c extinct sources such as fossil fuel combustion and relict bc in uplifted source rocks combining these pan arctic data with available estimates of bc export from other rivers gave a revised estimate of global riverine bc export flux of 26 103 kton a 1 this is twice higher than a single previous estimate and confirms that river export of bc is a more important pathway of bc to the oceans than direct atmospheric deposition

high resolution planktonic foraminiferal analysis from the cretaceous tertiary boundary at ain settara tunisia evidence of an extended mass extinction the ain settara section located in the kalaat senan area of north central tunisia spans the cretaceous tertiary k t boundary which is characterized by a red layer and a thin non bioturbated boundary clay sediment accumulation across the k t boundary at ain settara was probably interrupted by three short hiatuses and or condensed sedimentation the first hiatus occurs at the top of the cf1 zone the second hiatus condensation occurred just below the boundary clay and the third hiatus at the p0 p1a boundary in the earliest danian these hiatuses are marked by weak unconformities bioturbation and sudden disappearances appearances of species which are known to disappear evolve sequentially in continuous sections quantitative high resolution planktonic foraminiferal analysis across zones cf1 upper p0 and p1a 1 reveals an extended and selective mass extinction all 41 of the species which disappeared at or below the k t boundary are rare to very rare and primarily ecologically specialized keeled deeper dwelling tropical subtropical forms globotruncana globotruncanita gublerina planoglobulina rosita contusotruncana racemiguembelina their combined relative abundance varies between 10 and 15 of the total population at the end of the maastrichtian the k t crisis thus appears more catastrophic when viewed in tropical subtropical assemblages and based on analysis of larger species 200 m which preferentially includes the more specialized forms though in fact the k t mass extinction actually involved a relatively small part of the foraminiferal population in terms of relative abundance the pattern of extinction and changes in dominant population at ain settara appear to be very similar to the planktonic foraminiferal turnover of the other north central tunisian sections el kef elles the selective mass extinction pattern suggests that the catastrophic effects of the bolide impact superimposed those related to long term environmental changes such as variations in temperature sea level and associated water mass changes

flux and budget of bc in the continental shelf seas adjacent to chinese high bc emission source regions this study conducted the first comprehensive investigation of sedimentary black carbon bc concentration flux and budget in the continental shelves of bohai sea bs and yellow sea ys based on measurements of bc in 191 surface sediments 36 riverine water and 2 seawater samples as well as the reported data set of the atmospheric samples from seven coastal cities in the bohai rim bc concentrations in these matrices were measured using the method of thermal optical reflectance the spatial distribution of the bc concentration in surface sediments was largely influenced by the regional hydrodynamic conditions with high values mainly occurring in the central mud areas where fine grained particles median diameters 6 i e 0 0156mm were deposited the bc burial flux in the bs and ys ranged from 4 to 1100 mu g cm 2 yr and averaged 166200 mu g cm 2 yr which was within the range of burial fluxes reported in other continental shelf regimes the area integrated sedimentary bc sink flux in the entire bs and ys was 325gg yr and the bs alone contributed 50 157gg yr the bc budget calculated in the bs showed that atmospheric deposition riverine discharge and import from the northern yellow sea nys each contributed 51 47 and 2 therefore atmospheric deposition and riverine discharge dominated the total bc influx 98 sequestration to bottom sediments was the major bc output pattern accounting for 88 of the input bc water exchange between the bs and the nys was also an important bc transport route with net bc transport from the bs to the nys