phanerozoic evolution of the basins of northern egypt and adjacent areas the results of integrating geological well data and geophysical information from the subsurface of northern egypt are presented in terms of basin dynamics recent biostratigraphic data from wells and scarce outcrops are shown to be critical to an understanding of syndepositional tectonics six tectonostratigraphic phases of basin evolution are recognized to span the phanerozoic these phases initially record the development of intracratonic subsidence controlled by deep crustal strike slip tectonics as nubian continental and tethyan marine influences competed across the northern margin of gondwanaland evidence is also presented for the formation of the present day continental margin to northern egypt after a phase of crustal stretching oceanic rifting focused on the western margin of the arabian platform propagating progressively westwards during the early mid jurassic thereafter the effects of passive subsidence on the continental margin were disturbed by discrete phases of intracratonic strike slip associated syrian arc folding and the formation of deep basins in the opening red sea and gulf of suez three structural fabrics persisted throughout phanerozoic basin evolution the result of repeated extensional reactivation and inheritance from pan african basement

biotic and geochemical response to anoxic events the aptian pelagic succession of the gargano promontory southern italy microfossil distribution patterns and high resolution 13 c and 18 o curves calibrated against planktonic foraminiferal and calcareous nannofossil data are provided for the aptian pelagic coppitella section of the gargano promontory southern italy the succession consists of cyclically arranged couplets of bioturbated grey marlstones and off white marly limestones referable to the marne a fucoidi in the lower portion of the section two thin black shales were recognized the high resolution 13 c curve presented here correlates with those of other alpine tethyan sections albeit with lower absolute values the onset of deposition of organic rich sediments falls at the top of the interval of unchanging carbon isotope values whereas the upper black shale is documented from the interval of the main aptian positive 13 c excursion according to our biostratigraphic data the deposition of organic matter in the gargano promontory persisted through early late aptian boundary time using a chemostratigraphic definition only the lower black shale is referred to the selli level as far as the biotic response is concerned the onset of the nannoconid crisis is recorded considerably below the lower black shale whereas the globigerinelloides eclipse is recorded below and within the upper black shale the distribution of meso eutrophic indices zygodiscus spp radiolaria vs moderate fertility indices rhagodiscus asper and lithraphidites carniolensis testifies to a modest increase of surface water fertility only throughout the stratigraphically higher black shale the occurrence of a benthic foraminiferal fauna albeit impoverished in both the basal and upper black horizons clearly documents dysaerobic rather than completely anoxic conditions on the sea floor relative sea level rise at the time of the selli event in the gargano promontory is documented by drowning and foundering of the apulia platform margin situated adjacent to the basin in which the marne a fucoidi accumulated

gravity field of the moon from the gravity recovery and interior laboratory grail mission spacecraft to spacecraft tracking observations from the gravity recovery and interior laboratory grail have been used to construct a gravitational field of the moon to spherical harmonic degree and order 420 the grail field reveals features not previously resolved including tectonic structures volcanic landforms basin rings crater central peaks and numerous simple craters from degrees 80 through 300 over 98 of the gravitational signature is associated with topography a result that reflects the preservation of crater relief in highly fractured crust the remaining 2 represents fine details of subsurface structure not previously resolved grail elucidates the role of impact bombardment in homogenizing the distribution of shallow density anomalies on terrestrial planetary bodies

sedimentology and depositional profile of a mid cretaceous shelf edge rudist reef complex nahal ha mearot northwestern israel abstract during the cretaceous rudists became the most important constructors of reefs at steep shelf margins rudists formed large biohermal reef barrier island complexes one such reef complex is exposed as an unfaulted section at nahal ha mearot nw israel the reef at nahal ha mearot which was constructed by radiolitid rudists and chondrodonts had a back reef shallowing depositional profile coarse storm deposited back reef gravels accumulated behind the reef and periodically formed back reef islands in front of these disrupted reef flat floatstones pass basinward into in situ rudist clusterstones which accumulated in slightly deeper water depositional dips increased basinward from the reef onto the upper and mid fore reef which respectively comprised floatstones and grainstones compared with modern coral frameworks the radiolitid rudists at nahal ha mearot formed relatively low energy mud supported clustered reef fabrics these low energy rudist reef fabrics grew down profile from the shelf crest gravels which formed the major hydrodynamic barrier the back reef shallowing profile of the nahal ha mearot reef facilitated the development of reef facies back stepping in response to relative sea level rise

re os molybdenite age of the cu mo skarn ore deposit at suoerkuduke in east junggar nw china and its geological significance the suoerkuduke cu mo ore is a medium sized skarn deposit in the east junggar orogen of the southern altaids xinjiang northwest china we measured re os isotopes of a molybdenite veinlet from the

correlation of early cretaceous carbon isotope stratigraphy and platform drowning events a possible link the early cretaceous carbonate carbon isotope record is marked by three positive high amplitude 1 5 excursions each covering time spans of more than 106 years they are of late valanginian hauterivian and early and late aptian age in a case study along a transect across the western tethys ocean we identified a coincidence between 13c excursions black shale formation and widespread carbonate platform drowning events we conclude that the 13c excursions reflect a change in partitioning of carbon between the organic and carbonate carbon sinks which was triggered by climate induced ecological changes in cretaceous pelagic and neritic environments episodes of intensified greenhouse climate conditions led to an increase in weathering erosion and runoff rates and to elevated nutrient transfer rates from continents into oceans the resulting increase in oceanic nutrient levels favoured marine phytoplankton production and black shale deposition while conditions for carbonate producing biotas became unfavourable partial choking of carbonate production along river influenced coasts resulted in widespread carbonate platform drowning during times of sea level rise in the valanginian and aptian widespread contemporaneous black shale deposits and drowned carbonate platforms therefore reflect the contrasting response of the marine organic and carbonate carbon pumps to nutrient enhanced phytoplankton productivity the change in marine carbon partitioning is mirrored in a shift of the 13c record towards more positive values the transition to the 13c peak values lasted up to several hundred thousand years the peaks of the excursions also covering a time span of up to several hundred thousand years reflect a new stabilisation of the carbon partitioning between carbonate and organic carbon sinks a renewed intensification of carbonate sedimentation under mesotrophic conditions was facilitated by stabilisation of the sea level rise at a high level decreasing 13c values record increasing carbonate carbon burial rates at constant or decreasing organic carbon accumulation rates these changes contributed to the stabilisation of the marine carbon budget and the global carbon cycle up to millions of years after its initial perturbation

ecological succession palaeoenvironmental change and depositional sequences of barremian aptian shallow water carbonates in northern oman barremian and aptian shallow water carbonate facies uppermost lekhwair kharaib and shuaiba formations are described from outcrops in northern oman based on facies analysis and bedding pattern three orders of depositional sequences are defined third to fifth order and correlated between sections over the course of three third order sequences covering the barremian to lower aptian a third order depositional pattern is documented that consists of a succession of three distinct faunal assemblages discoidal orbitolinids and calcareous algae were deposited during early transgression microbialites and microencrusters dominate the late transgressive to early highstand facies and a rudist and miliolid dominated facies is typical of the highstand this ecological succession was controlled largely by palaeoenvironmental changes such as trophic level and clay influx rather than sedimentological factors controlled by variations in accommodation space orbitolinid beds and carbonates formed by microbialites and microencrusters seem to be the shallow water carbonate response to global changes affecting late barremian to aptian palaeoclimate and palaeoceanography

recognition of late ordovician yudai porphyry cu au mo mineralization in the kalatag district eastern tianshan terrane nw china constraints from geology geochronology and petrology abstract although the eastern tianshan terrane in xinjiang nw china occupies a critical position in the central asian orogenic belt caob the early paleozoic tectonic evolution and mineralization history of this terrane remain ambiguous the yudai deposit is a newly discovered porphyry cu mo au deposit in the kalatag district of the dananhu island arc a key area containing early paleozoic rocks in the eastern tianshan this paper reports the geologic characteristics molybdenite re os ages zircon la icp ms u pb ages and geochemical and lu hf isotopic findings regarding the ore hosting porphyries in the yudai deposit the yudai ore hosting porphyries include an early diorite porphyry and a late quartz diorite porphyry alteration and mineralization have formed distinct zones around the quartz diorite porphyry with disseminated vein or veinlet cu mo au mineralization types mainly related to potassic alteration e g biotite magnetite and quartz typical of a porphyry cu deposit two molybdenite samples have an re os weighted mean age of 449 5 4 2 ma and exhibit high re contents 2624 to 4704 ppm indicating a mantle component the observed mineralization was probably related to the quartz diorite porphyry which yielded a mean zircon 206pb 238u age of 452 7 2 8 ma the rock samples from the two porphyries mainly plot in the diorite field show metaluminous to weak peraluminous features and belong to tholeiitic to calc alkaline series with k2o na2o ratios of 0 16 0 34 and mg values of 44 2 50 3 the samples also exhibit steep chondrite normalized rare earth element and relatively flat heavy rare earth element patterns indicating residual amphibole with positive eu anomalies eu eu 1 09 1 45 the samples are enriched in large ion lithophile elements relative to high field strength elements typical of arc magma in addition the rocks show adakitic features sr y 47 8 73 5 and present high ba th and low th nb ratios indicating slab fluids the zircons from the quartz diorite porphyry mainly yield high ehf t values 13 5 14 7 and very young two stage hf model ages tdm2 494 556 ma consistent with a depleted mantle origin combined with the arc tectonic setting we propose that the ore metals and ore hosting porphyries at yudai were predominately derived from the partial melting of the amphibole bearing and fluid rich kangguer ocean slab that was subducted northward beneath the dananhu island arc in the late ordovician therefore the evolutionary history of the dananhu island arc can be traced back to the late ordovician the yudai deposit is the first age constrained early paleozoic porphyry cu deposit in the eastern tianshan terrane and the early paleozoic was an important epoch of mineralization on this terrane

volcanism co2 and palaeoclimate a late jurassic early cretaceous carbon and oxygen isotope record a composite tethyan late jurassic early cretaceous carbon and oxygen isotope curve is presented c isotope data provide information on the evolution and perturbation of the global carbon cycle o isotope data are used as a palaeotemperature proxy in combination with palaeontological information the resulting trends in climate and in palaeoceanography are compared with biocalcification trends and oceanographic conditions favouring or inhibiting biocalcification positive c isotope anomalies in the valanginian and aptian correlate with episodes of increased volcanic activity regarded as a source of excess atmospheric carbon dioxide a major warming pulse accompanies the aptian but not the valanginian c isotope event the observed change in early aptian temperatures could have triggered the destabilization of sedimentary gas hydrates and the sudden release of methane to the biosphere as recorded as a distinct negative carbon isotope pulse preceding the positive excursion both c isotope anomalies are accompanied by biocalcification crises that may have been triggered by p co 2 induced changes in climate and in surface water chemistry elevated nutrient levels in river influenced coastal waters and in upwelling regions further weakened marine calcification these conditions contrast with normal trophic conditions prevailing in the latest jurassic and favouring biocalcification the c and o isotope curves record a stable mode of carbon cycling and stable temperatures we conclude that biocalcification is mostly triggered and inhibited by co 2 conditions in the atmosphere ocean system

palaeobathymetric reconstruction of peritidal carbonates late barremian urgonian sequences of provence se france abstract peritidal platform carbonates of late barremian age early cretaceous cropping out in the marseille region provence se france tend to be arranged stratigraphically in deepening up or shallowing up sequences seven facies types lithofacies were defined in the studied stratigraphic interval ranging from supratidal to shallow subtidal settings there is a good correspondence between the inferred relative water depth of facies and their average bed thickness cumulative thickness of facies types expresses quantitatively their palaeobathymetric range and provides an estimate of their average water depth calculations show that the palaeobathymetry of supratidal intertidal facies types is from 0 to 40 cm i e a pertaining to a palaeotidal microtidal range the average palaeobathymetry of rudist facies ascribed to subtidal settings fluctuates between 40 cm and nearly 160 cm measuring a large number of beds belonging to both shallowing up and deepening up sequences and averaging the results appear relevant to minimise the effect of compaction pressure solution and synsedimentary progressive or abrupt changes in accommodation which are expected to modify bed thickness and its original palaeobathymetric significance the method proposed here has a good potential for palaeobathymetric reconstruction of ancient peritidal carbonates

testing polar spots of water rich permafrost on the moon lend observations onboard lro 1 results are presented for the lend instrument onboard lro for the detection of local spots of suppression and excess of epithermal neutron emission at the lunar poles twelve local neutron suppression regions nsrs and neutron excess regions ners are detected it is shown using the data from the lola and diviner instruments that six nsrs have the empirical property less local irradiation and lower temperature fewer local neutrons these nsrs may be identified with spots of water ice rich permafrost on the moon it is shown that detected nsrs are include in both permanently shadowed and illuminated areas and they are not coincident with permanently shadowed regions psrs at the bottom of polar craters as has been commonly expected before lend presented neutron data with high spatial resolution

the clementine mission to the moon scientific overview in the course of 71 days in lunar orbit from 19 february to 3 may 1994 the clementine spacecraft acquired just under two million digital images of the moon at visible and infrared wavelengths these data are enabling the global mapping of the rock types of the lunar crust and the first detailed investigation of the geology of the lunar polar regions and the lunar far side in addition laser ranging measurements provided the first view of the global topographic figure of the moon the topography of many ancient impact basins has been measured and a global map of the thickness of the lunar crust has been derived from the topography and gravity

tectonic development of the eastern mediterranean region the eastern mediterranean region is a classic area for the study of tectonic processes and settings related to the development of the tethyan orogenic belt the present set of research and synthesis papers by earth scientist from countries in this region and others provides an up to date interdisciplinary overview of the tectonic development of the eastern mediterrenean region from precambrian to recent key topics include continental rifting ophiolite genesis and emplacement continental collision extensional tectonics crustal exhumation and intraplate deformation e g active faulting alternative tectonic reconstructions of the tethyan orogen are presented and discussed with important implications for other regions of the world the book will be an essential source of information and interpretation for academic researchers geologists and geophysicists advanced undergraduates and also for industry professionals including those concerned with hydrocarbons minerals and geological hazards e g earthquakes

carbonate platform sequence stratigraphy in a rapidly subsiding area the late barremian early aptian of the organya basin spanish pyrenees abstract a detailed sedimentological and stratigraphical study of the late barremian early aptian urgonian carbonate platform of the organya basin spanish pyrenees has identified four depositional sequences the first two sequences consist of transgressive and highstand systems tracts and the last two sequences of lowstand transgressive and highstand systems tracts sequence boundaries at the top of sequences or 1 and or 4 are type 1 boundaries with evidence of exposure and erosion sequence boundaries at the top of sequences or 2 and or 3 are type 2 with no evidence of exposure or erosion sand shoal high energy facies characterise the first sequence or 1 sequences or 2 and or 3 are dominated by lagoonal facies with an important accumulation of lacustrine facies at the base of or 3 a succession of lacustrine deep platform and sand shoal facies characterises sequence or 4 the last sequence also contains the record of an anoxic event oae 1a all these characteristics have been largely influenced by the high subsidence rate of the organya basin 1100 m of compacted limestone deposited in about 5 ma however the main global eustatic changes registered in other contemporaneous basins were also identified

the structure of the dead sea basin abstract the dead sea basin is located along the left lateral transform boundary between the arabian and sinai plates its structure and history are known from surface geology drilling seismic reflection and other geophysical data the basin comprises a large pull apart almost 150 km long and mostly 8 10 km wide which is flanked by a few kilometres wide zones of normal faulting the basin formed at about 15 ma or earlier close to the beginning of the transform motion and it reached about half its present length before the end of the miocene a strong negative gravity anomaly records a thick sediment basin fill 5 km under half its length reaching a maximum of 10 km the fill includes a few km of salt ca 6 4 ma which forms several diapirs at any one time large parts of the basin subsided simultaneously but the site of fastest subsidence seems to have shifted northward sedimentation rates reached at least hundreds of metres per million years or more in the miocene and 1 km myr in later periods the basin structure is dominated by longitudinal faults intrabasinal faults which delimit the pull apart and which are the extensions of the major strike slip faults north and south of the basin and normal faults which extend along the basin margins the latter faults express a small component of extension across the basin whereas the pull apart resulted from the much larger lateral motion along the basin in addition transverse faults divide the pull apart into several segments with somewhat different histories the pull apart grew by becoming longer parallel to the transform motion at shallow levels this was probably achieved by normal slip on transverse listric faults while the fill between them was little deformed the crust under the basin was stretched and thinned during basin lengthening which caused its subsidence basin formation was accompanied by uplifting of its flanks by 1 km sparse igneous activity occurred along the basin and its flanks its presence suggests a thermal anomaly in the lower lithosphere beneath the basin and adjacent parts of the transform

timing of mid cretaceous carbonate platform depositional cycles northern sinai egypt abstract the northern sinai upper aptian to middle cenomanian succession represents an example of a carbonate platform where stratigraphic interpretations are mainly based on benthic foraminifera ostracods and rudists this paper presents a concept combining the stratigraphic study of benthic organisms with graphic correlation and sequence stratigraphy at a scale that determines the timing of sequence boundaries and quantification of sediment accumulation rates biostratigraphic analyses result in multibiostratigraphic zonations and contribute to a northern sinai fossil range chart for benthic larger and smaller foraminifera ostracods and rudists the age interpretation results from the careful comparison of the ages given in the literature and the distribution patterns in the northern sinai sections the northern sinai chart for many fossil ranges matches with other studies but also indicates some exceptions ostracods were grouped into assemblages characterised by short local ranges which enables the exact correlation of different sections the use of graphic correlation techniques within this framework improves the stratigraphic resolution and results in timing of the sequence boundaries these chronostratigraphic assignments allow comparison of the sinai sequence boundaries with those described from other regions furthermore graphic correlation measures long term sediment accumulation rates of the northern sinai based on their variations we calculate the relative sea level changes resulting in a detailed second order sea level curve in the upper aptian to middle cenomanian succession important changes in the long term sediment accumulation rate were measured they reflect three second order sea level cycles which subdivide a general relative sea level rise 18 sequences superimpose the second order sea level change 3 sequences in the upper aptian 11 sequences in the albian and 4 sequences in the lower middle cenomanian both sequence stratigraphic patterns and long term sea level changes were compared with those from the tethyan domain the african arabian plate and the western pacific abundance and distribution of the sinai sequence boundaries were similar to the patterns described from other regions we distinguish between sequence boundaries with regional extent correlating with examples from the north african arabian plate or the western pacific sequence boundaries of possibly global or tethyan extent and the few sequence boundaries of local extent the influence of the regional and global signals on the studied successions reflect the sinai location between the southeastern and southwestern tethyan realms local tectonics or changes in subsidence are only of subordinate importance for the creation of sequence boundaries the comparison of the chronostratigraphic assignments of the second order sea level curve with other descriptions indicates a second order relative sea level history of its own for sinai triggered by the interaction of subsidence sediment supply and eustasy

the western central asian orogenic belt a window to accretionary orogenesis and continental growth abstract the architecture of accretionary orogens is a key to understand continental growth here we present an overview of the orogenic components and their amalgamation in the western central asian orogenic belt caob the caob records the convergence and interactions among various types of orogenic components including the japan type mariana type and alaska aleutian type arc systems as well as the active marginal sequences of the siberia craton which incorporated wide accretionary complexes and accreted arcs and terranes during construction of the caob the kazakhstan arc chain was characterized by multiple subduction whereas the northern fringe of the tarim craton remained mostly as a passive margin the multiple convergence and accretions among these various orogenic components generated huge orogenic collages in the late paleozoic and even in the early triassic involving parallel amalgamation circum microcontinent amalgamation and oroclinal bending the preservation of trapped basins played a significant role in orogenesis with some parts of the oceanic plate being subducted and others behaving as rigid units the orogenesis in the caob was long lived lasting for more than 800 m y involving multiple subduction and long continuous accretion and featuring the complexity of accretionary orogenesis and continent growth

microfacies biostratigraphy and geochemistry of the hemipelagic barremian aptian in north central tunisia influence of the oae 1a on the southern tethys margin upper barremian lower upper aptian hemipelagic deposits of the hamada formation in the djebel serdj area north central tunisia were studied in detail with regard to microfacies biostratigraphy 13 c stratigraphy and geochemistry our data provide insights into the palaeoenvironmental evolution and sea level fluctuations of the tunisian shelf the unusually expanded deposits consist of mud wacke and packstones which reflect mid and outer ramp depositional environments planktonic foraminifer and 13 c stratigraphy allowed us to establish a detailed time frame and the recognition of the lower aptian oceanic anoxic event 1a oae 1a as well as time equivalent deposits of shallowmarine carbonate platform drowning based on our microfacies studies we subdivide the studied sections into four genetic intervals a pre oae 1a interval an oae 1a and platform drowning equivalent interval and a post platform drowning interval we present a 3rd order sea level curve for the tunisian shelf deriving from the results of our microfacies studies deposits of the oae 1a in the sections investigated are characterised by bioclastic wacke and packstones with high abundances of poorly preserved radiolarians and moderately to well preserved planktonic foraminifers suggesting a transgression and an eutrophication of the upper water column scarceness of benthic macrofossils low abundances of small benthic foraminifers and ostracods possibly suggest dysoxic conditions at the seafloor mudstones of the platform drowning time equivalent deposits directly overlying the oae 1a are partly showing a pronounced drop in carbonate content and are scarce of macrofossils 2008 elsevier b v all rights reserved

simulation of multiangular radar echoes for speed measurement during ce 3 landing on the lunar sinus iridum surface the main objective of the chinese chang e 3 ce 3 lunar satellite is to achieve soft landing and roving exploration on the lunar surface a multibeam radar in the lunar lander is implemented to measure the echoes from the lunar rough surface during its descending and to derive the speed of the lander in this paper numerical simulation of multiangular radar echoes and speed inversions from doppler frequency are presented an area of the lunar sinus iridum bay as landing site is specifically selected the rough surface described with the real dtm data is first divided into triangular patches for numerical kirchhoff approximation calculation the radar echoes of multiangular radar beams of ce 3 during the landing are numerically simulated the echo phase and the doppler frequency are then derived to obtain the vertical speed

the evidence and implications of polar ice during the mesozoic abstract the mesozoic perhaps representing the longest period of warmth during phanerozoic earth history contains in general sparse and frequently equivocal evidence for polar ice although this time is undoubtedly punctuated by oscillations in climate whether sufficient to lead to polar cooling and the formation of polar ice an inviting mechanism to account for faunal and floral distribution patterns and large scale sea level change has been widely debated mesozoic evidence for glacial conditions includes abraded rock surfaces generally unsorted stone rich beds and the presence of dropstones rafted by ice within a finer grained host sediment faunal and floral evidence has also been utilised to determine the presence or absence of cold or sub freezing polar conditions together with more indirect evidence for glacial conditions derived from general circulation model gcm simulations of climate the analysis of clay mineral distributions glendonite abundance and palaeontological and sedimentological evidence for globally synchronous sea level change the extent of possible glacial environments during the mesozoic has been established by plotting published reports of glacial sediments on palaeogeographic reconstructions the general clustering of evidence at high palaeolatitudes suggests that the extent of polar ice during the mesozoic is likely to have been approximately one third the size of the present day based on such evidence a number of episodes of cold or sub freezing polar climates during the bajocian bathonian tithonian volgian valanginian and aptian are recognised evidence exists possibly also for a cold episode during the early jurassic pliensbachian although poorly constrained owing to limited biostratigraphical control the longevity of these events may be represented by a cold snap within a stage although undoubtedly the possible smearing of ages may have had the effect of lengthening and hence promoting the importance of these proposed events the climate regime of the earth during these times may be hypothesised to be characterised by a relatively steep pole to equator temperature gradient where low latitude regions are as warm or warmer than today the evidence to support such reasoning includes sharp increases in the areal distribution of both glendonites and deposits with affinities to glacial tillites and dropstones for these times coincidental falls of sea level arid events and an increased bipolarity of faunas at these times imparts further confidence that these events were of a magnitude to effect the earth as a whole

low rhenium molybdenite by metamorphism in northern sweden recognition genesis and global implications abstract re os dating of molybdenite is an accurate means to date intrusions and intrusion related ore deposits using the model age or isochron approach but molybdenite has a new niche in the greenschist to granulite facies metamorphic environment re os ages for metamorphic molybdenite may be used to construct regional metamorphic histories age significance and accuracy are established by analyzing multiple molybdenite separates extracted from single petrographically characterized molybdenite occurrences in this study twelve geologically distinct molybdenite bearing samples from two small mo districts in northern sweden trace a 150 m y paleoproterozoic svecofennian metamorphic history from 1900 to 1750 ma these data reveal a little known widespread and protracted late svecofennian anatexis in northern sweden the kataberget mo cu f deposit is located in the moskosel granite batholith north of the economically renown skellefte district four different molybdenite samples from outcrop at kataberget indicate an intrusion age of 1895 6 ma with the formation of later pegmatite aplite at 1875 6 ma the allebuoda bjorntjarn and munka mo w deposits in the rappen district are represented by three outcrop and five drill core samples of molybdenite bearing aplite pegmatite granite these two deposits were previously described as intrusion related climax type mo mineralization re os ages for molybdenites from these deposits range from 1865 to 1750 ma and significantly re concentrations are markedly low extending to the sub ppm level age agreement within the deposits is conspicuously lacking whereas with one exception age agreement within any single sample geologic occurrence as established by analysis of additional molybdenite separates is very good these data together with fundamental geologic observations discussed in this paper suggest that mo w mineralization in northern sweden is not intrusion related but the local product of episodic melting of archean paleoproterozoic supracrustal gneisses related to the svecofennian orogeny petrographic traverses across the boundary between widespread foliation parallel units of aplitic to pegmatitic pink granite and hosting biotite gneiss directly capture the process of ore formation dehydration breakdown of zircon rich biotite aligned with the foliation in the gneiss is accompanied by formation of new pristine post deformational biotite plus sulfides oxides hydrothermal zircon and fluorite all associated with microcline dominant leucosomes this process has profound implication for the traditional leucogranite intrusion related genesis attributed to the broad classification of mo w sn base and precious metal mineralization e g south mountain batholith nova scotia okiep namaqualand south africa mactung yukon pogo liese tintina alaska carajas and goias rio tocantins brazil new england batholith nsw australia bergslagen sweden nevoria western australia alpeinerscharte austria erzgebirge germany sardinia corsica batholith in addition to biotite metallogenic contributions e g mo w sn u bi cu pb zn fe ni co au ag te as sb ree in various combinations may also be controlled by breakdown of amphibole in effect the trace element composition of dehydrating or recrystallizing components in a gneissic rock essentially defines the local and district metallogenic suite in the absence of focusing structures e g shear zones sheeted vein development this process will generally form small and disconnected subeconomic deposits with erratic and unpredictable grades low re content in associated molybdenite is a key indicator for a subeconomic origin by local melting of biotite gneiss mo w or muscovite schist sn w

lower aptian carbon isotope stratigraphy from a distal carbonate shelf setting the cau section prebetic zone se spain a n 13 c curve is reported for the latest barremian to early aptian at a section located in the prebetic zone cau section se spain the studied section records a hemipelagic succession of dark shales deposited on a distal carbonate ramp with a high subsidence rate adjacent to shallow carbonate environments the integrated biostratigraphy of the section is based on ammonites planktonic foraminifera and calcareous nannofossils and it has allowed an accurate dating of the succession the n 13 c curve presented shows a distinctive evolution leading to the recognition of three major excursions as well as a subdivision into eight segments which represents an improvement of the current biostratigraphic resolution the correlation both isotopic and biostratigraphical with other well resolved sections is very accurate even at the higher resolution attained correlation with sections with lowresolution biostratigraphic characterisation from shallow platform limestones also gives good results which supports the effectiveness of carbon isotope stratigraphy as a correlation tool

guidelines for reporting zircon hf isotopic data by la mc icpms and potential pitfalls in the interpretation of these data invited technical paper high quality analytical data are essential for the development of sound scientific interpretations to ensure the quality of the data published in chemical geology a new type of contribution has been introduced the invited technical paper when a particular technical issue needing discussion or clarification is identified specialists in the technique will be invited to share their expertise as is true for all articles published in the journal these contributions will be subject to peer review before publication the first topic to be treated concerns in situ hf isotopic measurements in zircon by laser ablation inductively coupled plasma mass spectrometry this is an extremely powerful and promising technique that has been adopted by many laboratories throughout the world however if insufficient care is taken during analysis and data processing inaccurate results can be obtained notably because of the existence of very large isobaric interferences on the isotope of interest to address this issue we have asked christopher fisher jeffery vervoort and john hanchar to provide a set of guidelines that can be adopted to assure that reliable hf isotopic data are obtained by this technique abstract over the past decade the hf isotope composition of zircon as determined in situ by laser ablation multicollector inductively coupled plasma mass spectrometry la mc icpms has been applied increasingly to a wide range of geological problems and has proven to be a valuable analytical tool there has been no uniformity however in the reporting of in situ hf isotopic data and quite often reviewers and readers of papers are not provided with sufficient information to assess data quality the goal of this invited contribution is to provide the non specialist with a brief outline and explanation of what is required for proper presentation and documentation of in situ hf isotopic data from zircon including details of how the challenging large isobaric interference corrections have been made in addition we discuss a number of potential pitfalls vis a vis the assignment of the incorrect age to the measured hf isotope composition non specialists should be aware of these important issues when doing their own analyses and evaluating the analyses done by others

microbial foraminiferal episodes in the early aptian of the southern tethyan margin ecological significance and possible relation to oceanic anoxic event 1a two regionally significant microbial foraminiferal episodes 150 kyr each occur within the early aptian shallow marine platform in oman and throughout eastern arabia the stratigraphically lower of these two intervals is characterized by isolated or coalescent domes that share similarities with modern open marine stromatolites from the exuma cays bahamas the upper interval is predominantly built by a problematic lithocodium bacinella consortium in buildup and massive boundstone facies based on highresolution chemostratigraphy these shoalwater intervals are coeval with oceanic anoxic event 1a oae1a livello selli field evidence demonstrates that the buildup episodes alternate with stratigraphic intervals dominated by rudist bivalves this biotic pattern is also recognized in other coeval tethyan sections and is perhaps a characteristic shoalwater expression of the oae1a the short lived regional expansions of this microbial foraminiferal out ofbalance facies cannot be explained by local environmental factors salinity and oxygen level alone and the buildup consortia do not occupy stressed refugia in the absence of grazing metazoans judging from recent analogues the main fossil groups i e microbial assemblages macroalgae larger sessile foraminifera and rudist bivalves all favoured elevated trophic levels but with different tolerance limits the implication of this is that the influence of palaeofertility events possibly related to oae1a on carbonate platform community structures must be investigated the observations made in these coastal sections are a significant first step for the improved understanding of the early aptian period of biotic oceanic and climatic change

farside gravity field of the moon from four way doppler measurements of selene kaguya the farside gravity field of the moon is improved from the tracking data of the selenological and engineering explorer selene via a relay subsatellite the new gravity field model reveals that the farside has negative anomaly rings unlike positive anomalies on the nearside several basins have large central gravity highs likely due to super isostatic dynamic uplift of the mantle other basins with highs are associated with mare fill implying basalt eruption facilitated by developed faults basin topography and mantle uplift on the farside are supported by a rigid lithosphere whereas basins on the nearside deformed substantially with eruption variable styles of compensation on the near and farsides suggest that reheating and weakening of the lithosphere on the nearside was more extensive than previously considered

absence of major vegetation and palaeoatmospheric pco2 changes associated with oceanic anoxic event 1a early aptian se france the deposition of organic rich sediments during the late early aptian oceanic anoxic event oae 1a has been interpreted to result in a major decrease of palaeoatmospheric co2 concentrations accompanied by significant changes in the terrestrial flora in order to test this hypothesis the oae 1a interval in the vocontian basin se france has been studied with a combined approach including stable carbon isotopes organic geochemistry and palynology to estimate changes in palaeoatmospheric co2 levels across the oae 1a the 13c composition of presumed algal biomarkers low molecular weight n alkanes steranes and of bulk carbonate carbon are used our results yield estimated early aptian carbon dioxide partial pressure pco2 values three to four times the preindustrial level and only a moderate drop across the black shale event this moderate drop in pco2 is supported by palynological results the frequency patterns of climate sensitive sporomorphs incl pteridophyte spores bisaccate pollen and classopollis spp display only minor fluctuations throughout the studied section and indicate relatively stable patterns of terrestrial vegetation during and after formation of the oae 1a black shale the occurrence of a characteristic early aptian carbon isotope pattern across the oae 1a interval permits accurate chemostratigraphic correlation with the well studied livello selli interval of the cismon record n italy the contemporaneous formation of individual black shale layers at both sites indicates that transient episodes of dysoxic anoxic bottom waters prevailed over large areas in the w tethys ocean independent of depositional setting comparison of the palynological data from the two locations displays significant differences in the frequency patterns of bisaccate pollen the contrasting pollen spectra are interpreted to reflect prominent changes in the palaeoceanographic current patterns and or selective sorting due to sea level rise rather than latitudinal shifts of the major floral belts

evolution of the marine stable carbon isotope record during the early cretaceous a focus on the late hauterivian and barremian in the tethyan realm abstract in order to improve our understanding of the relationships between the late hauterivian oceanic anoxic faraoni event contemporaneous platform drowning along the northern tethyan margin and global environmental change in general we established high resolution 13 c and 18 o curves for the late hauterivian and the entire barremian stage these data were obtained from whole rock carbonate samples from the veveyse de ch tel saint denis section switzerland the fiume bosso section and the nearby gorgo a cerbara section central italy and the angles section barremian stratotype france we observe an increase of 0 3 in mean 13 c values within sediments from the middle hauterivian subsaynella sayni ammonite zone to the hauterivian barremian boundary 13 c values remain essentially stable during the early barremian during the latest early barremian and most of the late barremian 13 c values increase slowly until the imerites giraudi zone and the latest barremian is characterized by a negative trend in 13 c values with minimal values at the barremian aptian boundary during the earliest aptian 13 c mean values start to rise again and attain 2 25 we interpret the evolution of the 13 c record as resulting from the interaction between changes in the carbon cycle in the tethyan basin and the adjacent platforms and continents in particular changes towards warmer and more humid conditions on the continent and coeval phases of platform drowning along the northern tethyan margin may have contributed to enhance the oceanic dissolved inorganic carbon dic reservoir which may have pushed the 13 c record towards more negative values and exerted a general attenuation on the 13 c record from this may have come the general change from a heterozoan to a photozoan carbonate platform community which influenced the evolution in 13 c values by increasing the export of aragonite and diminishing export of dissolved organic carbon into the basins

new constraints upon isotope variation during the early cretaceous barremian cenomanian from the pacific ocean carbon and oxygen isotope data from a succession of cretaceous barremian cenomanian age recovered from the pacific ocean dsdp site 463 are presented the carbon isotope curve reveals a large isotope excursion within the early aptian where 1 3 c values reach 4 8 in the l cabri g ferreolensis foraminifera zone a decrease in 1 3 c values is observed at the base g algerianus zone before a return to more positive values at the top of the g algerianus t bejaouaensis zone the pronounced early aptian positive event is preceded by a large negative isotope excursion confined to the g blowi zone synchronous with this excursion are increased total organic carbon values and increases in mn and fe concentrations integrated biostratigraphic and magnetostratigraphic data together with the carbon isotope profile suggest that the organic rich units of site 463 are correlatable with oceanic anoxic event la the input of isotopically light volcanic co 2 in concert with the intensification and upwelling of intermediate water enriched in 1 2 c could account for the observed trends a potential trigger may have been the destabilization of the water column and the prodigious co 2 emissions associated with hydrothermal activity and the emplacement of the ontong java plateau coupled with faunal evidence the subsequent positive carbon isotope excursion is interpreted to be resulting from high but decreasing productivity and possibly increasing ocean stratification resulting in strong carbon isotopic gradients and 1 3 c enriched surface waters the decrease in 1 3 c within the g algerianus zone is coincident with more positive 1 8 o values if these are interpreted in terms of temperature this interval may be characterized by a period of cooling and possibly a waning of c o r g cycling a return to lower 1 3 c values during the middle albian is considered to be related to the increased influence of upwelling as opposed to a waning of c o r g cycling upwelling introduced isotopically light carbon to the surface arresting the stratified oceanic conditions

response of early cretaceous carbonate platforms to changes in atmospheric carbon dioxide levels during the late barremian and early aptian about 120 million years ago intense volcanic degassing and extremely rapid release of methane hydrates contained in marine sediments added high amounts of carbon to the ocean and atmosphere and resulted most probably in rising atmospheric carbon dioxide pressure in order to document the response of the shallow water carbonate producing communities to this pronounced disturbance of the carbon cycle we studied a late barremian to early aptian neritic carbonate succession deposited on the northern tethyan shelf swiss alps the sedimentological and stable carbon and oxygen isotope records of two sections located along a n s transect from proximal to more distal shelf environments were investigated the sediments correspond to outer mid and inner ramp deposits of a homoclinal carbonate ramp vertical facies variations within the two studied sections feature three progradation phases of the platform a highly resolved correlation of the shelf sediments with a pelagic succession from the southern alps northern italy is based on both 13c stratigraphy and biostratigraphy and indicates that the drowning of the helvetic carbonate platform coincided with a pronounced calcification crisis of calcareous nannofossils the biocalcification crisis started before but culminated during the aptian methane event recorded in a negative carbon isotope spike we propose that increased carbon dioxide concentrations in oceans and atmosphere related to volcanic activity and to sudden methane release reduced the marine calcium carbonate oversaturation and the calcification potential of benthic and planktonic organisms carbonate producing shallow water communities on platforms and ramps suffering from additional environmental stress such as extreme temperatures or high nutrient levels could not survive during times of rising sea level and as a consequence carbonate platforms drowned

variation of foraminiferal sr ca over quaternary glacial interglacial cycles evidence for changes in mean ocean sr ca 1 records of sr ca changes in planktonic and benthic foraminifera from diverse hydrographic settings reveal coherent variability 5 1 between ocean basins and between surface and deep waters over the past 300 kyr there is a general increase in foraminiferal sr ca over the penultimate glaciation declining to minimum values during stage 5 and an increase in sr ca from stage 5 through stage 2 coincident changes in benthic foraminifera records from the atlantic and pacific basins imply that sr ca variations are not dominated by dissolution planktonic culturing data provide evidence that the downcore sr ca variations are not controlled by temperature changes and suggest only a small influence of salinity and ph variation common to the records is most readily explained by changes in mean ocean sr ca if fossil foraminifera reliably record higher glacial seawater sr ca coral sr paleothermometry would underestimate sea surface temperature during glacialepisodes

re os isotopic dating of molybdenites in the xiaoliugou w mo deposit in the northern qilian mountains and its geological significance abstract the xiaoliugou is a large scale w mo deposit newly explored in the northern qilian mountains caledonian fold belt northwestern china it is a vein and skarn type deposit genetically associated with the xiaoliugou caledonian granodiorite stock re os isotopic dating for the molybdenite in the deposit yields an isochron age of 462 13 ma 2 and model ages of 436 to 496 ma these results suggest that w mo mineralization occurred before the collision of plates and mineralized substances mainly originated from the crust

the lunar opposition surge observations by clementine abstract the clementine mission to the moon in 1994 provided the first multispectral observations of the lunar opposition surge below a few degrees the brightness of the moon increases more than 40 between solar phase angles of 4 and 0 the opposition effect exhibits a small wavelength dependence the surge is 3 4 larger at 0 41 m than at 1 00 m this result suggests that the principal cause of the lunar opposition surge is shadow hiding while coherent backscatter if present makes only a minor contribution the amplitude of the effect depends significantly on terrain the surge is about 10 greater in the lunar highlands this difference is attributed to textural variations between the two terrains the clementine measurements provide a new basis for deriving spectral geometric albedos phase integrals and bond albedos a value of 0 11 0 01 was found for the lunar bolometric bond albedo this value is at the low end of the historical published values but not as low as the recent result of 0 080 0 002

interactions between environmental change and shallow water carbonate buildup along the northern tethyan margin and their impact on the early cretaceous carbon isotope record 1 the evolution of the early cretaceous northern tethyan carbonate platform was not only influenced by changes in sea level detrital influx and surface water temperature but also by changes in trophic levels we distinguish between phases of carbonate production dominated by oligotrophic photozoan communities and by mesotrophic and eventually colder water heterozoan communities superimposed on this bimodal trend in platform evolution were phases of platform demise for which we provide improved age control based on ammonite biostratigraphy the initial phase of these episodes of platform demise corresponds in time to episodes of oceanic anoxic events and environmental change in general on the basis of a comparison between the temporal changes in an early cretaceous ammonite calibrated d 13 c record from southeastern france and coeval changes in the platform record we suggest that the history of carbon fractionation along the northern tethyan margin was not only influenced by changes in the oceanic carbon cycle such as in the rate of production and preservation of organic and carbonate carbon and in the size of the oceanic dissolved inorganic carbon reservoir but it was also influenced by the above mentioned changes in the ecology and geometry of the adjacent carbonate platform phases of photozoan carbonate production induced positive trends in the hemipelagic carbonate d 13 c record phases of heterozoan carbonate production pushed the d 13 c system toward more negative values platform drowning episodes implied an initial increase in d 13 c values followed by a longerterm decrease in d 13 c values

significance to hydrocarbon exploration of terrestrial organic matter introduced into deep marine systems insights from the lower cretaceous in the levant basin abstract oil shows from wells in the levant basin and egypt are suggestive of potential economic discoveries within unpenetrated mesozoic reservoirs in the eastern mediterranean analysis of some of these oils indicate a non marine source of mixed deltaic terrestrial or lacustrine origin for the organic matter data from barremian aptian sediments from the mnuph 1 core in northern israel opens a window on potential importance of terrestrial sourced kerogen deposited in source rocks in a marine depositional environment core analyses of the barremian nabi sa id fm demonstrate the occurrence of a gas prone immature source rock of 77 m gross thickness averaging 4 6 toc peaking at 37 toc rock eval pyrolysis biomarker n alkane sterane and tricyclic terpane indices atomic c n ratios and 13corg ranges indicate mixed terrestrial marine organic source rocks for the barremian while higher up the aptian hidra fm contains source rocks with organic matter derived dominantly from carbohydrate rich land plants the interval at mnuph 1 includes abundant evidence for off shelf mass transport of terrestrial and proximal marine sediments into the deep marine basin these features are used to explain the anomaly of a terrestrial source for organic matter in this setting mass transport and consequent mixing of distal marine proximal marine and land derived sediment is in fact the norm at the foot of continental slopes globally the dominantly type iii source rocks described here would be unlikely to expel oil but might produce thermogenic gas thermogenic gas identified in similar marine settings might wrongly be interpreted as having been generated from marine organic matter misleadingly indicative of a prospective oil source when prospecting for deep rooted hydrocarbon accumulations in offshore marine settings an alternative system dominated by basinward sediment transport of gas prone terrestrial source rocks into strategically positioned toe of slope marine settings is supported here and could well be producing gas in the levant basin

review of the tectonics of the levant rift system the structural significance of oblique continental breakup abstract the levant rift system is an elongated series of structural basins that extends for more than 1000 km from the northern red sea to southern anatolia the system consists of three major segments the jordan rift in the south el gharb kara su rift in the north and the lebanese fault splay in between the rifted parts of this structural system are accompanied by intensively uplifted margins that mirror image the basinal pattern namely the deeper the basin the higher its margins and vice versa uplifts also occur along the fault splay section the jordan rift comprises axial basins that diminish in size from the south northwards and are separated from each other by shallow threshold zones along the axis of the rift where the margins are also subdued the lebanese fault splay consists of five faults that emerge from the northern edge of the jordan rift and trend like a fan between the north and the northeast one of these faults connects the jordan and el gharb kara su rifts the levant rift and its uplifted margins started to develop in the middle late miocene and most of the structural development occurred in the plio pleistocene the levant rift system is characterized by its oblique displacement and evidence for both dip slip and strike slip displacement was measured on its faults earthquakes also indicate that same mixed pattern some of them show strike slip offset and others normal it is generally conceded that the amount of normal offset along the boundary faults of the rift system reaches 8 10 km but the lateral displacement is disputed and offsets ranging from 11 to 107 km were suggested assessment of the available data led us to suggest that the sinistral offset along the levant rift system is approximately 10 20 km the similarity between the vertical and the lateral displacements the basin and threshold structural pattern of the rift model experiments in oblique rifting as well as the significant tectonic resemblance to the red sea and the east african rifts indicate that the levant rift is the product of continental breakup and it is probably an emerging oceanic spreading center

constrains on the origin and history of the eastern mediterranean basin abstract the basin formed along the northern passive margin of gondwanaland as a relict of the mesozoic neotethys in early mesozoic time though direct information from the basin itself is meagre the geology of its passive margins and the regional framework of the tethys evolution constrain the formation and history of the basin the eastern mediterranean and its passive margins are interpreted to have formed as a result of several faulting and continental breakup phases from early permian to middle jurassic times before pangaea s complete disintegration this led to the detachment of the eratosthenes and tauride blocks from the margins of the levant and herodotus basins respectively the latter merged in the northeast with the cyprus basin that extended along arabia s northern margin the main rifting probably occurred in the triassic leading to seafloor spreading in the herodotus and cyprus basins while along the levant margin important rifting also occurred in the jurassic during the initial rifting stages extension perpendicular to the levant margin was important but subsequently the tauride block drifted mainly northward the existence of the passive margins and slopes of the eastern mediterranean is documented at least from the end of the middle jurassic until then the basin was probably narrow 200 300 km but during the main phase of the africa laurasia separation it grew to twice its present width or more this scenario depends critically on the interpretation that the tauride block was originally located next to northeastern africa on the western side of the eratosthenes block plate convergence and consumption of the northern portion of the basin have taken place since mid cretaceous times but the active convergent boundary on its northern side formed only in the neogene by modification of earlier structures some intra plate deformation also took place especially in the neogene but it hardly changed the original configuration of the remaining portion of the basin