chronology of late wisconsinan glaciation in middle north america abstract we propose a chronology of late wisconsinan glacial fluctuations in middle north america from alberta to wisconsin based on radiocarbon dates derived solely from wood previous chronologies of the southwestern margin of the north american continental ice sheet have depended to a considerable degree on radiocarbon dates from fine grained organic sediment this material is commonly contaminated with older carbon resulting in chronologic confusion by using only dates from wood much of the confusion disappears however because of the scarcity of wood dates only four of the sixteen identified fluctuations are accurately dated an advance into iowa about 14 000 to 13 500 bp an advance into south dakota and iowa about 12 300 bp an advance into the lake michigan basin about 11 700 bp and an advance into the lake superior basin about 9900 bp in addition the beginning of late wisconsinan glaciation before 20 000 bp is fairly well documented none of the fluctuations in the western part of the region are accurately dated

the dead sea fault and related subsurface structures gaziantep basin southeast turkey late cretaceous and miocene collisions of the arabian anatolian and eurasian plates as shown by widespread ophiolitic exposures along the suture created favourable geological conditions for the formation of the surface and subsurface structures in the gaziantep basin southeast turkey the late cretaceous maastrichtian emplacement of the kocali karadut ophiolite complex induced subsidence in the northwestern zone of the kastel basin during the early alpine orogeny and influenced the structural evolution of the foreland area the dead sea fault which originated in the red sea in miocene time propagated towards the northwest in the suez gulf and the north northeast in southeast turkey and influenced the structural evolution of the gaziantep basin these two major tectonic events produced many thrusts thrust related subsurface and surface anticlines faults fractures flower structures and basaltic flows in the area geological and geophysical investigations indicate the existence of two important structural phases the older structures were formed during the late cretaceous movements but they have been reactivated by latest miocene tectonic activities with appearance of the strands of the dead sea fault in the sedimentary basin the geothermal studies show also that as a result of the tertiary transgressions and volcanic activity the northern and southern sectors of the gaziantep basin underwent differing subsidence and structural histories

late cenozoic tectonics and volcanism in the northwestern corner of the arabian plate a consequence of the strike slip dead sea fault zone and the lateral escape of anatolia abstract the study area is the northwestern corner of the arabian plate near the triple junction of anatolian arabia and africa late cenozoic tectonics and volcanism have developed essentially east of the dead sea fault zone dsfz the strike slip boundary of the arabian and african plates including vents situated in front of the bitlis collisional belt isotopic and rare elements data indicate deep mantle sources for volcanism our mapping based on radar imagery and digital elevation models suggests that elongate volcanoes volcanic ridges and linear clusters of adjacent volcanic vents are rooted on tension fractures which are a kilometer or several kilometers in length and infers similar development in depth we have also observed non volcanic tension fractures we have been able to map the northern segment of the dsfz as a continuous but broken fault line the ghab pull apart basin connects with appended faults including the choukhour fault that ends northward in a tail crack feature and the aafrine fault that ends in a tail thrust the amik pull apart basin is bounded in the west by a small but distinct scarp shown by radar imagery our image analysis and field data suggest that the left lateral amanos fault has a reverse throw component in consequence the amanos range has to be regarded as an anticline and the karasu valley as a syncline in the southern part of the study area the regional stress field is mainly strike slip with n020 striking tension fractures east of the amanos fault it becomes transpressive with n120 to n140 striking tension fractures in the north near the triple junction albeit compressional faults and belt environment predominate it is influenced by e w lowering horizontal stress component triggered by the lateral escape of anatolia and remains of the strike slip type associated with n020 striking tension fractures more east of the dsfz in front of the bitlis belt isolated volcanoes e g karacadag elongated n160 show in the rigid arabian crust local weak lines that can be influenced at a distance by the lowering horizontal stress component

rate of strike slip motion on the amanos fault karasu valley southern turkey constrained by k ar dating and geochemical analysis of quaternary basalts the left lateral amanos fault follows a 200 km long and up to 2 km high escarpment that bounds the eastern margin of the amanos mountain range and the western margin of the karasu valley in southern turkey just east of the northeastern corner of the mediterranean sea regional kinematic models have reached diverse conclusions as to the role of this fault in accommodating relative motion between either the african and arabian turkish and african or turkish and arabian plates local studies have tried to estimate its slip rate by k ar dating quaternary basalts that erupted within the amanos mountains flowed across it into the karasu valley and have since become offset however these studies have yielded a wide range of results ranging from 0 3 to 15 mm a 1 which do not allow the overall role and significance of this fault in accommodating crustal deformation to be determined we have used the cassignol k ar method to date nine quaternary basalt samples from the vicinity of the southern part of the amanos fault these basalts exhibit a diverse chemistry which we interpret as a consequence varying degrees of partial melting of their source combined with variable crustal contamination this dating allows us to constrain the quaternary slip rate on the amanos fault to 1 0 to 1 6 mm a 1 the dramatic discrepancies between past estimates of this slip rate are partly due to technical difficulties in k ar dating of young basalts by isotope dilution in addition previous studies at the key locality of hacilar have unwittingly dated different chemically distinct flow units of different ages that are juxtaposed this low slip rate indicates that at present the amanos fault takes up a small proportion of the relative motion between the african and arabian plates which is transferred southward to the dead sea fault zone it also provides strong evidence against the long standing view that its slip continues offshore to the southwest along a hypothetical left lateral fault zone located south of cyprus

α hch enantiomer fraction ef a novel approach to calculate the ventilation age of water in the arctic ocean 1 hch hexachlorocyclohexane and the enantiomeric fraction ef of its mirror image isomers have been determined for water column profiles in the southern beaufort sea in 2004 and 2007 using estimated rates of metabolic degradation we have applied a simple kinetic model to convert the observed efs to apparent ventilation ages of the water masses in the study region we found an age of 1 7 0 1 years for the polar mixed layer pml 6 6 0 6 for the core of the pacific layer centered at salinity 33 1 and 21 7 0 5 years for the core of the atlantic layer identified by a tmax of 0 5 c these ages are in reasonable accord with other methods used to date water masses in the arctic ocean suggesting that hch has an unexploited potential as a dating tool

questioning the age of the moorhead phase in the glacial lake agassiz basin abstract the stratigraphy of sites within the lake agassiz basin that constrain the timing of the onset of the moorhead low water phase is reexamined stratigraphic interpretation of the oldest date 10 960 14 c yr bp from cross bedded sand of the ojata beach is questioned particularly in light of demonstrated long distance transport and reworking of older organic material from elsewhere in the basin a maximum onset age for the moorhead phase is suggested from a 10 675 60 14 c yr bp age from wood in gravel from the base of the southern outlet whereas radiocarbon dates from in situ peat indicate a later minimum onset age of 10 340 100 14 c bp

was the younger dryas triggered by a flood draining of a huge lake into the northern atlantic may have triggered a cold period 12 900 years ago the route taken by the flood waters remains unknown

fall cone tests on clay sand mixtures abstract fall cone tests were performed on clay sand mixtures to investigate the variation of liquid limit with sand content and the link between undrained shear strength and water content for various sand contents in the mixtures five different particle gradations 4 75 0 075 mm 4 75 2 0 mm 1 18 0 6 mm 0 6 0 075 mm and 0 425 0 3 mm of sands having distinct shapes rounded and angular were added to a low plasticity clay with mixture ratios of 0 10 20 30 40 and 50 data of the clay sand mixtures showed that the depth of cone penetration against water content relationship is about linear the liquid limit estimates of the mixtures were measured to be slightly affected by the gradation and shape of the grains in the range of sand contents employed the obtained results indicated a decrease of undrained shear strength with an increase in the amount of sand the use of rounded sands in a clay matrix leads to the development of higher undrained shear strength values on which gradation of the sands has no effect

time and temperature in petroleum formation application of lopatin s method to petroleum exploration n v lopatin in the soviet union has developed a method for taking both time and temperature into account as factors in thermal maturation of kerogen lopatin s time temperature index of maturity tti values correlate with the thermal regimes corresponding to generation and preservation of hydrocarbons because such information is potentially of great interest for oil exploration a calibration and evaluation have been made of lopatin s method within the limitations of the data presently available the following statements can be made 1 the rate of the chemical reactions involved in thermal maturation of organic material appears to double with every 10 c 18 f rise in temperature 2 threshold values of lopatin s time temperature index of maturity tti are 15 onset of oil generation 75 peak oil generation 160 end oil generation 500 40 oil preservation deadline 1 000 50 oil preservation deadline 1 500 wet gas preservation deadline 65 000 dry gas preservation deadline 3 tti values calculated from lopatin reconstructions consistently agree with other maturation parameters commonly used by petroleum geochemists potential applications of lopatin s method for oil exploration include timing of oil generation calculation of volume of hydrocarbons generated within a basin and determination of economic deadlines

ar ar dating of late cenozoic basaltic volcanism in northern syria implications for the history of incision by the river euphrates and uplift of the northern arabian platform 1 ar ar dating of basalt flows capping terrace deposits of the river euphrates in northern syria has provided a new quantitative chronology for the late cenozoic evolution of this important river system and for the associated history of surface uplift of the northern arabian platform through which it flows a region of relatively strong crust that has experienced only slow deformation notably fluvial deposits 65 m above the euphrates are overlain by basalt dated to 2717 20 ka those 45 m above the river are overlain by basalt dated to 2116 39 ka and those 8 9 m above the river are overlain by basalt dated to 402 11 ka these new dates require the previous dating scheme based on paleolithic archaeology to be revised the euphrates terrace deposits and the associated incised valley are much older than was previously thought rates of incision by the euphrates providing a proxy for regional surface uplift that is inferred to be the isostatic response to regional erosion have varied significantly over the past 3 ma with indications that between 1 2 and 0 9 ma there was regional subsidence which gave rise to fluvial aggradation this unusual pattern involving reversals in the sense of vertical crustal motions is interpreted to be a consequence of a relatively cold and thin mobile lower crustal layer no more than 5 km thick evidently due to the presence of a much thicker underlying layer of mafic underplating at the base of the crust this study thus indicates previously unsuspected complexity in the isostatic response to regional erosion in an area of high crustal stability

the kinematics of central southern turkey and northwest syria revisited central southern turkey nw syria and adjacent offshore areas in the ne mediterranean region form the boundary zone between the turkish african and arabian plates a great deal of new information has emerged in recent years regarding senses and rates of active crustal deformation in this region but this material has not hitherto been well integrated so the interpretations of key localities by different teams remain contradictory we have reviewed and synthesised this evidence combining it with new investigations targeted at key areas of uncertainty this work has led to the inference of previously unrecognised active faults and has clarified the roles of other structures within the framework of plate motions provided by gps studies roughly one third of the relative motion between the turkish and arabian plates is accommodated on the misis kyrenia fault zone which links to the study region from the kyrenia mountain range of northern cyprus much of this motion passes nne then eastward around the northern limit of the amanos mountains as previously thought but some of it splays northeastward to link into newly recognised normal faulting within the amanos mountains the remaining two thirds of the relative motion is accommodated along the karasu valley some of this component steps leftward across the amik basin before passing southward onto the northern dead sea fault zone dsfz but much of it continues southwestward past the city of antakya then into offshore structures ultimately linking to the subduction zone bounding the turkish and african plates to the southwest of cyprus however some of this offshore motion continues southward west of the syrian coast before linking onshore into the southern dsfz this component of the relative motion is indeed the main reason why the slip rate on the northern dsfz measured geodetically is so much lower than that on its southern counterpart in some parts of this region notably in the karasu valley it is now clear how the expected relative plate motion has been accommodated on active faults during much of the quaternary rather than constant slip rates on individual faults quite complex changes in the partitioning of this motion on timescales of hundreds of thousands of years are indicated however in other parts of the region it remains unclear whether additional major active faults remain unrecognised or whether significant relative motions are accommodated by distributed deformation or on the many smaller scale structures present

renewal and circulation of intermediate waters in the canadian basin observed on the scicex 96 cruise during the summer of 1996 the nuclear submarine uss pogy occupied a line of stations extending through the middle of the canadian basin between about 88 n 44 w lomonosov ridge and about 78 n 144 w center of the canada basin ctd niskin bottle casts extending to 1600 m were carried out at eight stations providing the first high quality temperature salinity cfc tritium and 3he data obtained from this region although xctd data had previously been collected in this region these data along with data from stations at the basin boundary to the south and west reveal the presence of well ventilated intermediate water beneath the halocline in the center of the canada basin indicating renewal times of the order of 1 2 decades the least ventilated intermediate water was observed at the northern end of the canada basin along the southern flank of the alpha ridge intermediate water is derived from the atlantic ocean and enters the arctic ocean through fram strait and the barents sea it flows around the arctic basins in boundary currents and splits in the eastern amundsen basin with one branch crossing the lomonosov ridge and flowing along the east siberian continental slope and the other flowing along the eurasian flank of the lomonosov ridge from the 1996 scientific ice expedition scicex 96 observations we conclude that the branch that flows along the east siberian continental slope transports this water to the chukchi rise where it apparently enters the central canada basin with some flow continuing along the boundary to the southern canada basin the fram strait branch water mixes extensively with waters from the canadian basin during its transit along the east siberian continental slope being diluted by a factor of about 5 by the time it reaches the central canada basin the barents sea branch water does not undergo such extensive mixing and is diluted by a factor of only about 2 when it reaches the central canada basin

mid 1980s distribution of tritium 3he 14c and 39ar in the greenland norwegian seas and the nansen basin of the arctic ocean abstract the distributions of tritium 3 he 14c and 39ar observed in the period between 1985 and 1987 in the greenland norwegian seas and the nansen basin of the arctic ocean are presented the data are used to outline aspects of the large scale circulation and the exchange of deep water between the greenland norwegian seas and the nansen basin additionally semi quantitative estimates of mean ages of the main water masses found in these regions are obtained apparent tritium 3 he ages of the upper waters depth 1 500m depth of the greenland norwegian seas show apparent tritium 3 he ages between about 17 years in the greenland sea and 30 years in the norwegian sea 39ar based estimates of the nansen basin intermediate deep and bottom water ages are 91 26 23 161 50 44 and 277 33 31 years for arctic intermediate water aiw eurasian basin deep water ebdw and eurasian basin bottom water ebbw respectively within the errors age estimates of ebdw and ebbw based on 14 c tritium correlations are consistent with those derived from 39ar 163 to 287 years for ebdw and 244 to 368 years for ebbw a quantitative evaluation of the data in terms of deep water formation and exchange rates based on box model calculations is presented in an accompanying paper

routing of meltwater from the laurentide ice sheet during the younger dryas cold episode rooth1 proposed that the younger dryas cold episode which chilled the north atlantic region from 11 000 to 10 000 yr bp was initiated by a diversion of meltwater from the mississippi drainage to the st lawrence drainage system the link between these events is postulated to be a turnoff during the younger dryas cold episode of the north atlantic s conveyor belt circulation system which currently supplies an enormous amount of heat to the atmosphere over the north atlantic region2 this turnoff is attributed to a reduction in surface water salinity and hence also in density of the waters in the region where north atlantic deep water nadw now forms here we present oxygen isotope and accelerator radiocarbon measurements on planktonic foraminifera from orca basin core en32 pc4 which reveal a significant reduction in meltwater flow through the mississippi river to the gulf of mexico from about 11 200 to 10 000 radiocarbon years ago this finding is consistent with the record for lake agassiz which indicates that the meltwater from the southwestern margin of the laurentide ice sheet was diverted to the northern atlantic ocean through the st lawrence valley during the interval from 11 000 to 10 000 years before present yr bp

kinematic consistency between the dead sea fault zone and the neogene and quaternary left lateral faulting in se turkey a revised quantitative kinematic model has been determined for the dead sea fault zone dsfz and the left lateral fault zones in se turkey the relative motions of the african and arabian plates across the dsfz are represented by relative rotation about 31 1 n 26 7 e at 0 40 0 02 ma 1 the northern dsfz in syria and southern turkey is interpreted for the first time as a series of transpressional stepovers along which the left lateral slip rate is substantially less than the rate of relative plate motion because this slip is oblique to the plate motion the slip rate on the east anatolian fault zone eafz is estimated as 8 mm a 1 restoring its observed slip thus requires its age to be 4 ma the previous phase of deformation which involved slip on the malatya ovacik fault zone mofz before the eafz came into being is thus dated to 7 4 ma suggesting initiation of the north anatolian fault zone nafz at 7 ma not 5 ma as previously thought the total left lateral slip on the northern dsfz in southernmost turkey is estimated as at least 65 km partitioned with 45 km on the amanos fault 10 km on the east hatay fault and a further 10 km on the kirkpinar fault farther east much of this slip is inferred to have occurred during the miocene before the modern geometry of this plate boundary zone developed when it first formed the af ar plate boundary was relatively complex it initially reactivated preexisting structures in the palmyra foldbelt in syria and in the gaziantep region of southern turkey which were significantly misaligned relative to the plate motion requiring major components of shortening as well as left lateral slip the transition from this initial rather diffuse geometry to the present localised geometry of the dsfz across western syria occurred within the miocene the predicted rate of relative motion between the stable interiors of the turkish and african plates in the vicinity of their common boundary onshore of iskenderun gulf in southern turkey is estimated as westward at 9 mm a 1 however this promontory of the african plate is itself moving westward relative to the stable interior of this plate at 7 8 mm a 1 the rate of localised left lateral slip on the onshore part of this boundary the ne trending yakapinar goksun fault is thus estimated as only 2 mm a 1 this locality can also be regarded as within the distributed boundary zone between the turkish and arabian plates the estimated relative motion between these plates is at 8 7 mm a 1 towards the ssw partitioned between localised left lateral slip at 2 mm a 1 on the yakapinar goksun fault and at least 1 mm a 1 on the amanos fault and 2 5 mm a 1 on east hatay fault with at most distributed left lateral simple shear at 3 2 mm a 1 across the amanos mountains in between however the combined slip on left lateral faults east of the amanos mountains may be as high as 6 mm a 1 with slip at 1 7 mm a 1 on the amanos fault and at 4 3 mm a 1 on the east hatay fault and any active faults farther east this requires no more than 0 7 mm a 1 of distributed simple shear across the amanos mountains raising the possibility that this component of deformation may in fact be zero this small nonzero estimate possibly indicating a closure error arising from minor errors in predicted values of other relative motion vectors it is proposed that this boundary between the turkish and african plates first developed at the same time as the mofz and nafz but its original geometry involving left lateral slip on the karatas osmaniye fault has since become locked by the presence of relatively strong ophiolitic crust within this fault zone this quantitative kinematic model demonstrates for the first time how it is possible for the left lateral faulting accommodating the nnw sse relative motion between the arabian and african plates in nw syria to dovetail into the left lateral faulting accommodating the wsw ene relative motion between the turkish and arabian plates in se turkey

palaeomagnetic study of tertiary volcanic domains in southern turkey and neogene anticlockwise rotation of the arabian plate abstract following collision with eurasia the arabian shield indenter has continued to deform into the weak anatolian collisional collage that resulted from subduction of the neotethyan ocean differential movements have involved rotation and continuing northwards translation and have been accommodated mainly by slip along major transforms including the northward extension of the dead sea fault zone dsfz and the east anatolian fault zone eafz to aid in evaluating post collisional motions the palaeomagnetism of extensive volcanic domains at the northern margin of the stable shield in southern turkey is reported here together with the timing of emplacement as constrained by k ar study the age dating results indicate that volcanic activity occurred mainly during mid late miocene times corresponding to the final stages of suturing volcanic fields in the east of the investigated region are younger and correspond to neotectonic volcanism in brunhes and matuyama chrons thermal and alternating field demagnetization of 399 cores from 83 sites in basaltic lavas identifies 29 units of normal and 43 of reversed polarity with 11 sites having transitional or random directions volcanic fields west of the euphrates kilis gaziantep region with ages in the range 7 0 20 3 ma average 14 9 ma sd 4 3 ma have mean remanence d i 353 52 38 sites 5 3 lava fields east of the euphrates urfa region are dated 10 4 12 1 ma and yield a comparable mean remanence d i 350 50 17 sites 6 0 these collections are shown to have properly recorded palaeosecular variation with only minimal inclination shallowing and inferred anticlockwise rotations with respect to eurasia since mid miocene times are 10 9 4 3 and 14 0 5 0 respectively these contrast with clockwise rotation of 6 3 4 3 derived from late matuyama brunhes epoch volcanic rocks immediately to the north west of the arabian margin where rotational impingement of the shield indenter into fault blocks within the karasu rift at the northern extension of the dsfz interacts with left lateral motion at a rate of 0 5 cm year along this zone to produce small scale vertical axis rotations results from the volcanic suites sited on the stable shield are compared with other results from the arabian plate to conclude that it did not rotate significantly following closure of the bitlis suture until late miocene early pliocene times since when it has rotated anticlockwise at a rate of 1 0 myr this is comparable to the present day rate of rotation deduced from gps and correlates with crustal separation and sea floor spreading in the red sea it also temporally links the rotation of the arabian plate to the initiation of the intracontinental transforms north and east anatolian fault zones within anatolia and to the subsequent extrusion of blocks within this accretionary domain by tectonic escape to the west

river runoff sea ice meltwater and pacific water distribution and mean residence times in the arctic ocean hydrographic and tracer data collected during ark iv 3 fs polarstern in 1987 arctic91 ib oden and aos94 ccgs louis s st laurent expeditions reveal the evolution of the near surface waters in the arctic ocean during the late 1980s and early 1990s salinity nutrients dissolved oxygen and 18 o data are used to quantify the components of arctic freshwater river runoff sea ice meltwater and pacific water the calculated river runoff fractions suggest that in 1994 a large portion of water from the pechora ob yenisey kotuy and lena rivers did not flow off the shelf closest to their river deltas but remained on the shelf and traveled via cyclonic circulation into the laptev and east siberian seas river runoff flowed off the shelf at the lomonosov ridge and most left the shelf at the mendeleyev ridge arctic91 and aos94 pacific water fraction estimates of upper halocline water the traditionally defined core of the pacific water mass document a decrease in extent compared to historical data the front between atlantic water and pacific water shifted from the lomonosov ridge location in 1991 to the mendeleyev ridge in 1994 the relative age structure of the upper waters is described by using the 3 h 3 he age the mean 3 h 3 he age measured in the halocline within the salinity surface of 33 1 0 3 is 4 3 1 7 years and that for the 34 2 0 2 salinity surface is 9 6 4 6 years lateral variations in the relative age structure within the halocline and atlantic water support the well known cyclonic boundary current circulation

strength of various sands in triaxial and cyclic direct shear tests abstract this paper presents the result of an extensive series of experimental investigation carried out in triaxial and cyclic direct shear tests on sands having various properties which were obtained from different locations in turkey and in northern cyprus in order to investigate the link between strength and physical properties i e shape of the sand particles three series of triaxial tests consolidated drained cd consolidated undrained cu and unconsolidated undrained uu for each were performed under three different confining pressure values 450 kpa 500 kpa and 550 kpa with a back pressure of 400 kpa the cyclic shear behaviour of the sands was tested by considering the normal stresses of 50 kpa 100 kpa and 150 kpa experimental results in both triaxial and cyclic direct shear tests showed a relation between the physical properties of the sands and the behaviour of them under monotonic and cyclic loading the given pictures show the physical differences similarities among the sands used during the investigation the goal of the presented experimental investigation is to have an understanding of the behaviour due to shape characteristics i e roundness sphericity of these four types of sands narli birecik trakya and crushed stone which are widely used in earthwork projects in certain parts of turkey and northern cyprus

phasing of deglacial warming and laurentide ice sheet meltwater in the gulf of mexico evidence is emerging that the tropical climate system played a major role in global climate change during the last deglaciation however existing studies show that deglacial warming was asyn chronous across the tropical band complicating the identification of causal mechanisms the orca basin in the northern gulf of mexico is ideally located to record subtropical atlantic sea surface temperature sst warming in relation to meltwater input from the laurentide ice sheet paired d 18 o and mg ca data on the planktonic foraminifer globigerinoides ruber from core en32 pc6 are used to separate deglacial changes in sst and d 18 o of sea water sst as calculated from mg ca data increased by 3 8c from ca 17 2 to 15 5 ka in association with heinrich event 1 and was not in phase with greenland air temperature subtracting tem perature effects from d 18 o values in g ruber reveals two excur sions representing laurentide meltwater input to the gulf of mex ico one of 1 5 from ca 16 1 to 15 6 ka and a second major spike of 2 5 from ca 15 2 to 13 0 ka that encompassed melt water pulse 1a and peaked ca 13 8 ka during the bolling allerod conversion to salinity through the use of a laurentide meltwater end member of 225 indicates that near surface salinity de creased by 2 4 during these spikes these results suggest that gulf of mexico sst warming preceded peak laurentide ice sheet decay and the bolling allerod interval by 2 k y and that heat was retained in the subtropical atlantic during heinrich event 1 consistent with modulation of deglacial climate by thermohaline circulation

iodine 129 137cs and cfc 11 tracer transit time distributions in the arctic ocean 1 time series measurements of the nuclear fuel reprocessing tracers 129i and 137cs and ventilation tracer cfc 11 were used to determine circulation time scales for atlantic water aw in the arctic ocean measurements in surface water are consistent with an advection model and transit times from the north sea of 1 4 years to the barents sea 3 6 years to the kara sea and 9 12 years to the north pole tracer ages for intermediate waters do not support an advection model because they vary with time the tracer relationships were employed to determine transit time distributions ttd using inverse gaussian functions that implicitly incorporate the effects of mixing in simulating fluid flow tracer concentrations were used to constrain the ratio of the width of the ttd to the mean age a measure of the relative importance of mixing giving values for most intermediate water regimes of 1 these results are in contrast to values 1 typical of the north atlantic indicating the greater relative importance of advection compared to mixing in the arctic ocean mean ages for aw increase from 12 20 years in the southern makarov basin to 30 40 years near the arctic outflow north of greenland a decline in with distance along the direction of aw boundary flow from the makarov into the canada basin may indicate relatively stronger mixing in regimes upstream of the makarov basin but also implies that ttds may differ from inverse gaussian functions for flow in the arctic domain

early to middle miocene intra continental basaltic volcanism in the northern part of the arabian plate se anatolia turkey geochemistry and petrogenesis continental basalts ranging in age from 16 5 to 19 08 ma crop out throughout the northern part of the arabian plate the basalts have distinctive petrographic characteristics such as rounded and skeletal olivine phenocrysts with abundant melt inclusions implying the mixing of two distinct magmas all of the analysed basalts are tholeiitic in composition the presence of quartz xenocrysts with clinopyroxene rims in some samples indicates that crustal assimilation was probably an important process during magma ascent to the surface and low mg number and high sio 2 contents of the basalts clearly show that they have experienced fractional crystallization as well as crustal contamination variations of the major and trace elements versus mgo show that olivine clinopyroxene plagioclase were the main fractionating minerals in terms of incompatible trace elements the basalts have oib like signatures with a slight depletion at nb ta on primitive mantle normalized diagrams the basalts have slightly lree enriched patterns with la yb n 5 5 to 6 7 la nb ratios are close to unity suggesting the melts may have originated in the asthenospheric mantle partial melting modelling based on ree data imply that the melts were not produced from a single mantle source depth which is either purely a spinel or garnet peridotite end member the samples lie on a binary mixing line between low degree melts 10 from spinel peridotite sources on a plot of la yb v dy yb requiring interaction of melts derived from both garnet and spinel peridotite fields melts originating from both sources were initially tapped by distinct magma chambers which subsequently hybridized into a single flow hybridized magma ascended to the surface along neogene strike slip faults which are linked to the dead sea fault zone

waters of the makarov and canada basins abstract hydrographic measurements from the 1994 arctic ocean section show how the makarov and canada basins of the arctic ocean are related and demonstrate their oceanographic connections to the eurasian basin the inflow into the makarov basin consists largely of well ventilated water within a broad band of densities from a boundary flow over the siberian end of the lomonosov ridge the boundary flow contains a significant component of dense shelf water likely originating in the barents kara and laptev seas earlier ice camp data show that the canada basin is relatively more isolated from this ventilation source in the canada basin shelf sources influenced by bering sea water appear to add cold waters with high silicate concentrations to the halocline and deeper in 1994 the halocline silicate maximum over the central makarov basin was absent evidence of the recent displacement of the upper s 33 1 halocline water from the chukchi east siberian sea region by water from the eurasian basin much of the makarov basin water in and below the halocline is in fact from the eurasian basin with admixture of waters from the canada basin suggested by their higher silicate concentrations mid depth eddies may transport anomalous properties into the central arctic and create property gradients or fronts in mid depth and deep waters the complex topography of the mendeleyev ridge chukchi plateau region also may assist spreading of water from the boundary into the interior atlantic layer characteristics in 1994 differed from previous general depictions in particular the core temperatures at the chukchi mendeleyev boundary were at least 0 2 c warmer on average than indicated in earlier work the recent warming at intermediate depth has resulted from inflow of atlantic waters that have been cooled relatively little during their transit of the norwegian sea

reply to comments by carlson et al 2009 on radiocarbon deglaciation chronology of the thunder bay ontario area and implications for ice sheet retreat patterns

neotectonic deformation linking the east anatolian and karatas osmaniye intracontinental transform fault zones in the gulf of iskenderun southern turkey deduced from paleomagnetic study of the ceyhan osmaniye volcanics 1 left lateral strike slip along the dead sea fault zone dsfz between the african and arabian plates is partitioned into a complex set of motions at its northern extension where arabia impinges into the anatolian collage as a result the nature of the contemporary link between the east anatolian and dead sea transforms is unclear to quantify strike slip motion expressed as tectonic rotations along the inferred southwest continuation of the east anatolian fault zone eafz we have investigated the paleomagnetism of young 1 ma volcanics in the adana basin gulf of iskenderun region comprising the ceyhan osmaniye volcanic suite this volcanism is sited close to the intersection between the sinistral karatas osmaniye fault zone kofz and the neotethyian suture nine sites from a basaltic lava field in the vicinity of osmaniye are entirely of normal polarity and in the context of their very young morphologies are assigned to the brunhes chron declinations are mostly clockwise from the present field this age assignment identifies rapid recent 780 ka uplift at the head of the gulf of iskenderun and is linked to a diversion of the ceyhan river drainage and ongoing regional tilting eight sites yield a mean declination of 11 3 10 implying clockwise block rotation on riedel type fractures on the northwest side of the kofz seven lavas sites from a volcanic succession near botas at the southwestern extension of the volcanic lineament are of reversed polarity and rotated counterclockwise by 43 7 with respect to the present field polarity k ar and morphological evidence indicate an assignment toward the latter part of the matuyama chron and identify rapid neogene block rotation of a flake within the kofz an inferred maximum slip rate of 0 6 cm year on this fault zone is comparable with lower estimates of slip on the eafz and suggests that most strike slip on the dsfz is now being partitioned to the west of the gulf of iskenderun on a developing strike slip zone linking with the cyprus arc

composition and modification of water masses in the mackenzie shelf estuary the distributions of 18o salinity temperature and nutrients have been used to quantify water sources to the mackenzie shelf in the beaufort sea comparison of water mass analyses with satellite imagery confirms that the meteoric runoff water is associated with the mackenzie plume the seasonally variable surface layer for the shelf is viewed as cycling between a reverse estuary in winter when the polar mixed layer pml is formed and a positive estuary in summer when the shelf waters respond to freshwater inputs runoff and ice melt we infer a standing stock of 3 7 m fresh water at the end of summer 1986 of which 30 owes its origin to the melting of sea ice our data coupled with river flow imply a freshwater flushing time for the mackenzie shelf at about 150 days to re form the pml during winter requires the removal of this seasonal fresh water through the combined processes of flushing and ice formation once this fresh water has been removed continued ice growth can produce new brine which would be observed as a deeper and saltier pml from the previous year a simple geochemical model shows that autumn conditions freshwater accumulation and the rate of flushing are important controls on the potential of the shelf to produce new brine and that winter runoff were it to distribute evenly across the shelf is sufficient to inhibit brine production

neotectonic deformation in the transition zone between the dead sea transform and the east anatolian fault zone southern turkey a palaeomagnetic study of the karasu rift volcanism in southern turkey ongoing differential impingement of arabia into the weak anatolian collisional collage resulting from subduction of the neotethyan ocean has produced one of the most complex crustal interactions along the alpine himalayan orogen several major transforms with disputed motions including the northward extension of the dead sea fault zone dsfz meet in this region to evaluate neotectonic motion on the amanos and east hatay fault zones considered to be northward extensions of the dsfz the palaeomagnetism of volcanic fields in the karasu rift between these faults has been studied remanence carriers are low ti magnetites and all except 5 of 51 basalt lavas have normal polarity morphological polarity and k ar evidence show that rift formation occurred largely during the brunhes chron with volcanism concentrated at 0 66 0 35 ma and a subsidiary episode at 0 25 0 05 forty four units of normal polarity yield a mean of d i 8 8 54 7 with inclination identical to the present day field and declination rotated clockwise by 8 8 4 0 within the 15 km wide hassa sector of the karasu rift the volcanic activity is concentrated between the amanos and east hatay faults both with left lateral motions which have rotated blocks bounded by nw se cross faults in a clockwise sense as the arabian block has moved northwestwards an average lava age of 0 5 ma yields a minimum cumulative slip rate on the system bounding faults of 0 46 cm year according with the rate deduced from the africa arabia euler vector and reduced rates of slip on the southern extension of the dsfz during plio quaternary times estimates deduced from offsets of dated lavas flows and morphological features on the amanos fault zone tectonophysics 344 2002 207 are lower 0 09 0 18 cm year probably because they are limited to surface fault breaks and do not embrace the seismogenic crust results of this study suggest that most strike slip on the dsfz is taken up by the amanos east hatay afrin fault array in southern turkey comparable estimates of quaternary slip rate are identified on other faults meeting at an unstable fff junction dsfz east anatolian fault zone karatas fault zone a deceleration in slip rate across the dsfz and its northward continuation during plio quaternary times correlates with reorganization of the tectonic regime during the last 1 3 ma including tectonic escape within anatolia establishment of the north and east anatolian fault zones bounding the anatolian collage in mid late pliocene times a contemporaneous transition from transpression to transtension and concentration of all basaltic magmatism in this region within the last 1 ma

effect of basement tectonics on hydrocarbon generation migration and accumulation in northern iraq 1 stratigraphic geophysical and remote sensing evidence shows that the basement of northern iraq is fragmented at various scales two large blocks have been recognized the northern mosul block south of the east west to west northwest east southeast trending taurus suture zone and the kirkuk block southwest of the northwest southeast trending zagros suture zone these blocks are in turn subdivided into smaller longitudinal blocks relative to the fold trends the mosul block was less stable and more uplifted relative to the kirkuk block and therefore its stratigraphic record is characterized by wider and more extensive erosion and or periods of nondeposition this led to a relatively poor development of the middle jurassic upper cretaceous potential source rocks ove the mosul block the difference in hydrocarbon resources between the mosul and kirkuk blocks is apparent from the estimated reserves of oil and gas in each development of grabens or half grabens enhanced the already favorable stratigraphic circumstances for the deposition and preservation of potential source rocks in the kirkuk block and locally improved the otherwise inhibiting environment in the mosul block these features show significant difference in their plan shape and relative arrangement in the two blocks in addition within each of the large blocks the synorogenic differential movement on longitudinal basement faults fault stacking had a great effect on hydrocarbon generation migration and entrapment the difference in basement tectonics between the mosul and kirkuk blocks reflects a regional difference in the afro arabian plate margin history along the taurus and zagros belts

seismic interpretation of carbonate depositional environments most seismic stratigraphic or seismic lithologic interpretations have been applied to clastic depositional systems because of their unique sedimentologic and mineralogic characteristics carbonate rocks are more difficult to study using seismic data increased knowledge of carbonate deposits and their petrophysical parameters and higher quality geophysical tools now permit a better understanding of carbonate rocks using seismic images in this paper seismic facies of carbonate rocks are characterized step by step from the basin to the supratidal environment 1 pelagic deposits shales and micritic limestone layers exhibit continuous parallel reflections with an apparently high frequency chalk deposits display continuous high amplitude reflections at the top and base with an internal reflection free zone 2 talus deposits are characterized by discontinuous oblique reflections of high amplitude carbonate debris flow generates chaotic reflections with hummocky surfaces channels exhibit erosional truncations 3 reef barriers are mound shaped biogenic deposits that display marginal onlapping reflections overlying reflections drape the reefs and underlying reflections exhibit pull up or pull down effects hyperbolic diffractions also may occur 4 platform border sands are mound shaped oblique reflections of moderately high amplitude 5 inner shelf strata are characterized by parallel continuous reflections typically displaying low frequency patch reefs may be distinguished within the inner shelf system mound shape drape of overlying reflections velocity anomalies and spurious events 6 where dolomitized the intertidal to supratidal facies exhibit a marbled zone a practically reflection free zone with a few discontinuous reflections diagenetic events such as paleokarst zones may be delineated using special analyses involving amplitude offset variations the study of carbonate depositional environments and petrophysical characteristics provides a more complete geologic insight including relative changes in sea level within a sedimentary basin such studies are fundamental in analyzing carbonate reservoirs and their paleogeographic settings

vertical profiles of ccl3f f 11 and ccl2f2 f 12 in the central arctic ocean basin the anthropogenic chlorofluoro methanes ccl3f f 11 and ccl2f2 f 12 have been measured to depths of 1800 m in the canada basin of the arctic ocean approximate position 85 50 n 108 50 w the measurements were made as part of the canadian expedition to study the alpha ridge cesar during april 1983 surface layer concentrations beneath the ice were 4 79 10 12 mol kg f 11 and 2 11 10 12 mol kg f 12 both profiles exhibit a rapid concentration decrease with depth through the halocline and very low but detectable concentrations at depths of 350 900 m in the atlantic layer in the arctic ocean deep water 900 1800 m concentrations are at or below our practical detection limit of 0 01 10 12 mol kg the profiles have been interpreted using two extreme case lateral ventilation models in order to place bounds on the water column ventilation rates the ventilation age of the upper portion of the halocline 60 150 m increases with depth from 4 to 14 years the core of the atlantic layer at this location appears to have been isolated from the surface for at least 30 years

seasonal variability of water mass distribution in the southeastern beaufort sea determined by total alkalinity and δ18o 1 we examined the seasonal variability of water mass distributions in the southeastern beaufort sea from data collected between september 2003 and august 2004 salinity total alkalinity ta and isotopic composition 18o of seawater were used together as tracers of freshwater input i e meteoric water and sea ice meltwater we used an optimum multiparameter analysis to identify the different water masses including the mackenzie river sea ice melt sim winter polar mixed layer pml upper halocline water uhw with core salinity of 33 1 psu pacific origin and atlantic water computed values of co2 fugacity in seawater fco2 sw show that the surface mixed layer sml remains mostly undersaturated 328 55 atm n 552 with respect to the average atmospheric co2 concentration 380 5 atm over the study period the influence of the mackenzie river fco2 sw 500 atm was relatively small in the southeastern beaufort sea and significant fractions were only observed on the inner mackenzie shelf the contribution of sea ice melt fco2 sw 600 atm was usually located between 120 and 180 m depth but could contribute to the sml during wind driven upwelling events in summer and autumn and during brine driven eddies in winter