3d analytic model for testing numerical tidal models a 3d analytic solution is presented for tides in channels with arbitrary lateral depth variation the solution is valid for narrow channels in which the lateral variation of the amplitude of tidal elevation is small the error introduced by the solution is on the order of a few percent in a tidal channel of a few kilometers in width the solution allows an arbitrary lateral depth variation and thus provides a wide choice of depth functions especially those with large bottom slopes the largest amplitude of the along estuary velocity appears on the surface in the deepest water the depth averaged velocity is the largest in the deepest water the time of flood ebb in deep water lags that in shallow water the time of flood ebb on the surface lags that at the bottom since this solution is simple and allows arbitrary lateral depth variations it can be used to demonstrate the first order tidal flow in narrow tidal channels of variable depth and to test high resolution numerical models with large depth gradients

stratigraphy of the 1902 and 1929 nuee ardente deposits mt pelee martinique mild nuee ardentes in 1902 1903 and 1929 1930 at mt pelee formed high aspect ratio h a r deposits i e deposits with a high thickness extent ratio in the riviere blanche channel several violent nuees ardentes from may to august 1902 yielded low aspect ratio l a r deposits unevenly blanketing an area of 58 km2 on the southwestern flank of the volcano three closely spaced nuees ardentes on august 30 additionally affected 56 km2 on the southeastern flank the l a r deposits are divided into eight stratigraphic units u1 u8 either compound or consisting of a single flow unit the deposits of the largest nuees ardentes on may 8 20 and august 30 1902 are identified as u1 u3 and u8 respectively and can be traced over most of the area individual l a r flow units are lenticular and show large erratic lateral variations of thickness and grain size most flow units consist of three distinct beds bed 1 is a few centimeters thick lenticular fines depleted layer bed 2 is the thickest layer and contains more silt sized ash than bed 1 it is normally graded as a whole though reverse grading may occur in the lower part bed 2 generally consists of two parts bed 2a nonbedded and bed 2b finer grained and laminated with cross bedding and duned structures bed 3 is a thin silty capping layer which contains accretionary lapilli the distribution of the l a r flow units especially of the coarse grained facies suggests that they were formed from overpressured blast flows expanding radially from the vent at a high rate in the same manner as the laterally directed blast of mount st helens on may 18 1980 the transport system of the major 1902 nuees ardentes was an inflated relatively low concentration turbulent cloud as suggested by several lines of evidence 1 the transported material was able to cross ridges up to 300 m high 2 many scour and fill and other erosional features can be observed in the deposits at any distance from the vent 3 survivors within the devastated area on may 8 did not experience a dense low profile cloud but instead a choking hot ash laden cloud 4 many human corpses in st pierre remained where they fell instead of having floated away if the current flow surge terminology were to be used the 1902 blast flows would be better considered as pyroclastic surges the normally graded multi layered structure of the flow units is also consistent with deposits primarily formed from relatively low concentration flows

an adaptive finite volume solver for ice sheets and glaciers 1 we have developed a new adaptive finite volume scheme for numerical simulations of ice sheets and glaciers the mathematical basis of the adaptive solver is represented by the finite volume method and irregular voronoi cell grids evaluation of spatial derivatives are obtained at cell edges from approximating the ice surface elevation locally by second order polynomials following a least squares approach the proposed scheme includes a simple and accurate method for handling discontinuities in ice thickness gradients along ice margins the flexibility of the voronoi cell structure allows for local mesh refinement in selected areas we show how increased mesh density along a steep ice margin may considerably increase overall numerical accuracy of an ice sheet simulation although the numerical scheme is not restricted to ice sheet representations using the shallow ice approximation sia we here use analytical sia solutions to test the accuracy of the method

neogene ignimbrites of the nevsehir plateau central turkey stratigraphy distribution and source constraints abstract in anatolia turkey extensive calc alkaline volcanism has developed along discontinuous provinces from neogene to quaternary times as a consequence of plate convergence and continental collision in the nevsehir plateau which is located in the central anatolian volcanic province volcanism consists of numerous monogenetic centres several large stratovolcanoes and an extensive mainly neogene rhyolitic ignimbrite field vent and caldera locations for the neogene ignimbrites were not well known based on previous studies in the neogene ignimbrite sequence of the nevsehir plateau we have identified an old group of ignimbrites kavak ignimbrites followed by five major ignimbrite units zelve sarimaden tepe cemilkoy gordeles kizilkaya and two smaller less extensive ones tahar sofular other ignimbrite units at the margin of the plateau occur as outliers of larger ignimbrites whose main distributions are beyond the plateau excellent exposure and physical continuity of the units over large areas have allowed establishment of the stratigraphic succession of the ignimbrites as from bottom to top kavak zelve sarimaden tepe cemilkoy tahar gordeles sofular kizilkaya our stratigraphic scheme refines previous ones by the identification of the zelve ignimbrite and the correlation of the previously defined akkoy ignimbrite with the sarimaden tepe ignimbrite correlations of distant ignimbrite remnants have been achieved by using a combination a field criteria 1 sedimentological characterisitics 2 phenocryst assemblage 3 pumice vesiculation texture 4 presence and characteristics of associated plinian fallout deposits and 5 lithic types the correlations significantly enlarge the estimates of the original extent and volume of most ignimbrites volumes range between 80 km 3 and 300 km 3 for the major ignimbrites corresponding to 2500 10 000 km 3 in areal extent the major ignimbrites of the nevsehir plateau have an inferred source area in the derinkuyu tectonic basin which extends mainly between nevsehir and the melendiz dag volcanic complex the kavak ignimbrites and the zelve ignimbrite have inferred sources located between nevsehir and derinkuyu coincident with a negative gravity anomaly the younger ignimbrites sarimaden tepe cemilkoy gordeles kizilkaya have inferred sources clustered to the south between the erdas dag and the melendiz dag volcanic complex we found evidence of collapse structures on the northern and southern flanks of the erdas dag volcanic massif and of a large updoming structure in the sahinkalesi tepe massif the present day derinkuyu tectonic basin is mostly covered with quaternary sediments and volcanics the fault system which bounds the basin to the east provides evidence that the ignimbrite volcanism and inferred caldera formation took place in a locally extensional environment while the basin was already subsiding drilling and geophysical prospecting are necessary to decipher in detail the presently unknown internal structure of the basin and the inferred probably coalesced or nested calderas within it

curie point depth from spectral analysis of magnetic data in erciyes stratovolcano central turkey curie point depth and heat flow values of the erciyes region are determined to identify the thermal regime of the central anatolia by applying the spectral analysis method to the magnetic anomaly data to compute the spectrum of the data the magnetic anomaly of the region is transformed into 2 d fourier domain to attain the average curie depth this method is useful in determining the top boundary of magnetic anomaly sources and reveals the curie depth as 13 7 km in the study area the obtained results imply a high thermal gradient 42 3 c km 1 and corresponding heat flow values 88 8 mwm 2 in the research area using the temperature value measured at borehole drilled by the general directorate of mineral research and exploration of turkey mta the values for the thermal gradient and heat flow value were computed as 50 7 c km 1 106 5 mwm 2 from the heat flow value the curie point depth was determined as 11 4 km in this region it is concluded from the obtained values that the region has very high geothermal potential caused by partial melting of the lower crust

descriptive nomenclature and classification of pyroclastic deposits and fragments recommendations of the iugs subcommission on the systematics of igneous rocks

mount st helens 1980 and mount pelee 1902 flow or surge the far reaching directed blast of mount st helens and the devastating nuees ardentes of mount pelee produced deposits that in many places consist of three main layers a basal gravelly or sandy layer 1 a massive or bedded ash layer 2 and a capping ash cloud layer 3 these thin and in part landscape mantling deposits are generally ascribed to pyroclastic surges and the dune bedding seen in parts of layer 2 has reinforced this interpretation there are several reasons however for preferring a pyroclastic flow origin 1 much of layer 2 is unequivocal pyroclastic flow 2 the tripartite subdivision and landscape mantling habit is similar to that displayed by ignimbrites of the low aspect ratio type 3 the deflation of a pyroclastic surge and the subsequent deposition of particulate material will tend not to conserve the fine ash and dust that are abundant in valley ponded parts of layer 2 and cannot explain the observed tendency for layer 2 to show stronger fines depletion on ridges than in valley bottoms and 4 the coarseness and the variance of grain size found within dune bedded bed sets in mount st helens layer 2 are like those of very weak pyroclastic surges and the dune bedding most likely resulted from local minor turbulence as could have been caused by surface roughness in a mountainous terrain littered with tree stumps and fallen trees in a thin depositing pyroclastic flow the directed blast and nuees ardentes at mount st helens and mount pelee are interpreted to have been violently emplaced pyroclastic flows producing deposits of low aspect ratio type the characteristics of which stem from an exceptionally high flow velocity

stratigraphy and age of the cappadocia ignimbrites turkey reconciling field constraints with paleontologic radiochronologic geochemical and paleomagnetic data the stratigraphy and age of the neogene cappadocia ignimbrites central turkey have been inferred in previous studies from fieldwork and k ar age determinations the resulting stratigraphic schemes however differed from each other suggesting that further studies were required to produce a reliable succession in this paper we examine the chronostratigraphy of mammalian remains recovered in the continental sediments interbedded with the cappadocia ignimbrites using recent advances in mammalian chronostratigraphy we evaluate selected taxa and faunal associations to place new and independent constraints on the ignimbrite ages the biostratigraphically bracketed ages concur with some published radiometric dates but they disagree with others principally at localities where major stratigraphic discrepancies have arisen in the literature in order to reconcile these apparent inconsistencies we combine at selected sites our field observations with the biostratigraphic and radiometric age limits and we compare these with the available geochemical and magnetic data this allows us to present revised age estimates and a revised stratigraphy which includes the correlation of the local sofular deposits with the large volume gordeles ignimbrite the issues faced in this study apply to other ignimbrite provinces in the world for instance ignimbrite eruption frequency in cappadocia is higher than the resolution of many published k ar ages furthermore different k ar ages have led to the description of individual and distinct ignimbrites that fieldwork and geochemical data allow to merge into a single ignimbrite argon loss from pumice samples leading to radiometric rejuvenation provides a likely explanation for most stratigraphic discrepancies cappadocia is the only documented ignimbrite field in which the chronostratigraphy of vertebrate remains provides better constraints on some ignimbrite ages than scattered k ar dates we further argue that k ar dates from the cappadocia area are too imprecise to establish a reliable magnetostratigraphic scheme for the ignimbrite succession with the exception of the not vert similar2 8 ma valibaba tepe ignimbrite

monitoring of soil erosion in cappadocia region selime aksaray turkey a fairy chimney is a conical rock formation typically found in the cappadocia region of turkey the geology of areas where fairy chimneys exist typically comprise a thick layer of tuff covered by a thin layer of basalt or other volcanic rocks that are more resistant to erosion than the underlying tuff fairy chimneys are formed where a small cap or boulder of the original basalt remains protecting a cone of tuff beneath it from erosion eventually the tuff will be undercut to the extent that the cap falls off and the remaining cone is then quickly eroded in this study the formation of fairy chimneys in the cappadocia region was examined by investigating the surface soil erosion a study area was selected and then scanned at five different times by a geodetic robotic total station at 40 cm horizontal and vertical intervals the volumes of the study area were calculated from the same height and erosion was calculated from the volume differences indicated by the data the relationship between erosion and meteorological data was analyzed and showed that erosion had increased due to climatic conditions particularly from the effect of rainfall

unraveling the electrical conductivity structure to decipher the hydrothermal system beneath the mt hasan composite volcano and its vicinity sw cappadocia turkey abstract to comprehend the hydrothermal potential beneath the mt hasan composite volcano and its vicinity three dimensional analyses of magnetotelluric data collected at 27 sounding locations were utilized to develop electrical conductivity or its reciprocal resistivity images in southwest cappadocia central anatolia turkey a low resistivity anomaly associated with a clay cap was observed in the resulting numerical models that followed the characteristics of the earlier theoretical models developed for the electromagnetic interpretation of hydrothermal systems the observed anomaly appeared in the form of a deep smectite smectite illite and illite chlorite sequence buried under the cover layers made up of welded ignimbrites contemporaneous sediments and monogenetic quaternary volcanism products further evidence was observed that indicated the presence of a relatively deep 4 6 km single magmatic chamber beneath mt hasan and the surrounding system the tuz golu fault and some other auxiliary faults within this system present a high correlation with the low to high resistivity interfaces in the vicinity of mt hasan

storm surge induced flux through multiple tidal passes of lake pontchartrain estuary during hurricanes gustav and ike abstract in september 2008 hurricanes gustav and ike generated major storm surges which impacted the lake pontchartrain estuary in louisiana this paper presents analyses of in situ measurements acquired during these storm events the main data used in the analyses were from three bottom mounted moorings equipped with conductivity temperature and depth sensors acoustic doppler current profilers adcps and a semi permanent laterally mounted horizontal acoustic doppler profiler adp these moorings were deployed in the three major tidal channels that connect lake pontchartrain with the coastal ocean a process similar to tidal straining was observed the vertical shear of the horizontal velocity was negligible during the inundation stage but a shear of 0 8 m s over a less than 5 m water column was recorded during the receding stage 2 3 times the normal tidal oscillations the surge reached its peak in the industrial canal 1 4 2 1 h before those in the other two channels the inward flux of water lasted for a shorter time period than that of the outward flux the inward flux was also observed to have much smaller magnitude than the outward flux 960 1200 vs 2100 3100 million m 3 the imbalance was believed to have been caused by the additional water into lake pontchartrain through some small rivers and inundation over the land plus rainfall from the hurricanes the flux through the industrial canal was 8 12 while the flux through the other two tidal passes ranged between 17 and 70 of the total but mostly split roughly half half of the remaining 88 92 of the total

low frequency sea level variability in the vicinity of the east river tidal strait the east river is a narrow tidal strait connecting long island sound with the lower hudson estuary the sound and estuary both communicate with the new york bight subtidal fluctuations in sea level difference between the ends of the strait which are coherent with barotropic flow through the strait are produced mainly by direct setup in the sound and estuary and by sea level fluctuations primarily wind forced in the bight approximately 70 of the variance in subtidal sea level difference can be accounted for by the two components of wind stress the direction of dominant wind forcing wind stress direction producing maximum response varies considerably with frequency response functions relating sea level difference to wind stress components computed for 128 day series for sea level and winds allow us to interpret the direction of dominant forcing in terms of the relative contributions of direct setup and sea level fluctuations in the bight

palynostratigraphy and vegetation characteristics of neogene continental deposits interbedded with the cappadocia ignimbrites central anatolia turkey a palynological analysis of the late miocene and early pliocene successions of the cappadocian volcanic province central anatolia turkey has been carried out with the aim of reconstructing the palaeovegetation and palaeoclimatic conditions the samples are collected from outcrop sections from three different localities a akdag b bayramhacili and g guzeloz the pollen spectra reveals the existence of a steppe vegetation dominated by amaranthaceae chenopodiaceae and artemisia typical of present day arid and semi arid continental areas i e middle east and asteraceae asteroideae in the a section late miocene developed in arid climatic conditions the flora of the g early pliocene and lower part of the b late miocene sections reflects steppes on which asteraceae asteroideae was dominant this flora also indicates arid conditions the development of trees in the upper part of the b section was possibly related to local paleoenvironmental conditions rather than a climatic change this study provides the first palynological data to reveal the presence of an amaranthaceae chenopodiaceae and artemisia steppe already during the late miocene in turkey

volcanological evolution of mount erciyes stratovolcano and origin of the valibaba tepe ignimbrite central anatolia turkey abstract mount erciyes 3917 m is the largest stratovolcano of central anatolia turkey the volcanological evolution of mount erciyes from pliocene quaternary to historical times exhibits two distinct stages 1 koc dag and 2 erciyes during the koc dag stage basaltic and andesitic lava flows were emitted from the cinder cones of kizil tepe and topakkaya tepe then koc dag pyroclastics were emplaced leading to a caldera collapse of 14 18 km in diameter with a volume estimated at 110 km3 two eruption phases separated by scoria fall and mud flow deposits are recognised associated with the caldera forming event during phase 1 plinian fall and pumice flows were emplaced on the eastern part of the volcano plinian fall deposits occur more than 50 km away from the source area the volume of tephra is estimated at 63 3 km3 16 km3 dense rock equivalent dre including 62 km3 of plinian fall and 1 3 km3 pumice flow deposits phase 2 mainly consists of pyroclastic flow deposits two pumiceous flow units and valibaba tepe ignimbrite vti the pumiceous flow deposits 4 2 km3 dre extend 30 km from the inferred source area towards the north and northeast the final pyroclastic flows of phase 2 occurred 2 8 ma ago and produced the vti the vti is a low aspect ratio welded ignimbrite and its volume is estimated at 40 km3 dre plinian fall deposits 0 8 km3 dre preceded the vti and are only observed on the eastern part of the volcano covering an area of 1500 km2 during the erciyes stage two eruptive cycles are defined the first cycle 2 6 0 17 ma is characterised by effusive extrusive and weakly explosive activity with emplacement of andesitic lava flows dacitic dome flows basaltic andesite lava flows and andesitic cones the second cycle involved dacitic extrusive and explosive activity located at the summit area and produced block and ash flows derived from rhyodacitic domes plinian fall surge and pumice flow deposits were emplaced prior to rhyodacitic dome extrusions the last event was the emplacement of debris avalanche deposits related to sector collapse caldera

a level set method for modeling the evolution of glacier geometry a level set method is proposed for modeling the evolution of a glacier surface subject to a prescribed mass balance this leads to a simple and versatile approach for computing the evolution of glaciers the description of vertical fronts and overriding phenomena presents no difficulties topological changes are handled naturally and steady state solutions can be calculated without integration over time a numerical algorithm is put forth as a means of solving the proposed model of glacier surface evolution it is evaluated by comparing different numerical solutions of the model with analytical and published numerical solutions the level set method appears to be a reliable approach for dealing with different glaciological problems

an isobaric isenthalpic magma mixing model for the hasan dagi volcano central anatolia turkey calc alkaline rocks of the hasan dagi volcano central anatolia turkey are products of arc volcanism triggered by continental collision volcanic rocks of the hasan dagi range in composition from basalt to rhyolite but are dominated by andesite and dacite considering only the mass transfer part of the process leads to an incomplete picture of magma chamber processes the exclusion of simultaneous calculations of heat and mass transfer between mixing magmas however has prevented petrologists from gaining new insights into the magma mixing process thus we report our experimental results in conjunction with modeling with melts to test the ideas concerning the petrogenesis of hasan dagi volcanic rocks and quantitatively model the relevant petrogenetic processes our results demonstrate that the chemical diversity of hasan dagi volcano is inconsistent with the closed system crystallization and differentiation thus 1 our experimental modeling 2 the agreement between the liquid line of descent defined by the natural rock data and the melts calculations and 3 the agreement between the mineralogy of the rocks and calculated mineralogy corroborate the conclusion that the isobaric isenthalpic magma mixing of basalt and rhyolite is the major controlling process in the petrogenesis of the hasan dagi magmas

thermal investigation in the cappadocia region central anatolia turkey analyzing curie point depth geothermal gradient and heat flow maps from the aeromagnetic data in this study curie point depth cpd heat flow geothermal gradient and radiogenic heat production maps of the cappadocian region in central anatolia are presented to reveal the thermal structure from the aeromagnetic data the large circular pattern in these maps matches with previously determined shallow 2 km in average depression estimated cpds in this depression filled with loose volcano clastics and ignimbrite sheets of continental neogene units vary from 7 to 12 km while the geothermal gradient increases from 50 to 68 c km heat flows were calculated using two different conductivity coefficients of 2 3 and 2 7 wm 1 k 1 the radiogenic heat production was also obtained between 0 45 and 0 70 w m 3 in this area heat flow maps were compared with the previous regional heat flow map of turkey and significant differences were observed in contrast to linear heat flow increment through the northeast in the previous map in the literature produced maps in this study include a large caldera like circular depression between nevsehir aksaray nigde and yesilhisar cities indicating high geothermal gradient and higher heat flow values in addition active deformation is evident with young magmatism in the neogene and quaternary times and a large volcanic cover on the surface boundaries of volcanic eruption centers and buried large intrusions are surrounded with the maxspots of the horizontal gradients of magnetic anomalies analytic signal as map pointing out exact locations of causative bodies is also presented in this study circular region in the combined map of as and maxspots apparently indicates a possible caldera

weak compositional zonation in a silicic magmatic system incesu ignimbrite central anatolian volcanic province kayseri turkey abstract the central anatolian volcanic province cavp one of four major volcanic provinces in turkey plays a significant role in the interpretation of the tectonic evolution of central anatolia the cavp developed within a complex collisional system involving the african arabian and eurasian plates during the miocene the volcanism exhibits complicated variations in mineralogical petrological and geochemical compositions resulting from post collisional lithospheric dynamics the incesu ignimbrite has 5 20 m thick and covers an area of 7800 km2 it is composed of three stratigraphic levels the lower level ll shows blackish brown and glassy welded structure the middle level ml is a well welded reddish pink in color and has large amounts of fiamme the upper level ul is grayish pink weakly welded and has rock fragments of different compositions the incesu ignimbrite is composed of plagioclase oligoclase andesine pyroxene augite clinoenstatite opaque minerals and low amount of amphibole biotite and quartz eutaxitic texture is dominant in ml and ll samples these levels are more strongly and contain more flattened pumice fragments and volcanic glass shards than in the ul a sharp color contrast defines the contact between ll and ml major trace and rare earth element of the incesu ignimbrite characterized by their rhyolite rhyodacite dacite composition medium high k calcalkaline and peraluminous nature show fractional crystallization primarily controlled by plagioclase clinopyroxene magnetite ilmenite and titanomagnetite sr and nd isotopic ratios of incesu ignimbrite display isotopic variations between the ignimbrite levels they exhibit a limited range in 87sr 86sr 0 7043 0 7049 and 143nd 144nd 0 512716 0 512760 the sr nd isotopic ratio of incesu ignimbrite reveals an age of 3 ma the ignimbrite evolved through fractional crystallization and crystal contamination of the parent magma derived from ocean island basalt oib like magma this suggestion is supported by the afc modeling based on the trace elements and sr isotope data variation of several major oxide concentrations fe2o3 tio2 cao and k2o trace element concetrations v sr cs and rb and trace element ratios ba rb sr k sr k nb rb sr rb y and rb nb versus sio2 concentration show the magma chamber that generated the incesu ignimbrite was compositionally zoned all geochemical and sr nd isotpic datas can be interepreted to be the result of a subduction related source

dating the exhumation of a metamorphic dome geological evidence for pre eocene unroofing of the nigde massif central anatolia turkey the timing of exhumation of metamorphic rocks and granitoids of the nigde metamorphic dome at the southern tip of the central anatolian crystalline complex is a matter of debate according to some authors the metamorphic rocks are overlain nonconformably by a sedimentary sequence of late maastrichtian to late palaeocene age in contrast other authors recently argued that the nigde dome represents an extensional core complex of oligocene early miocene age finally unroofed during late miocene times on the one hand the results of our study contradict the latter interpretation a sedimentary sequence of earliest eocene to early middle eocene age nonconformably overlies the high grade rocks of the nigde dome on its southeastern flank pebbles from the metamorphic rocks are ubiquitous in the conglomerates of this sequence as a result the nigde metamorphic rocks must have reached the surface before eocene times or at the very beginning of the eocene at the latest the uckapili granite whose crystallization age has been inferred to be early miocene has intruded the metamorphic complex during exhumation the granite is also found as pebbles within the conglomerates of the eocene sedimentary sequence and thus is actually older than the eocene apatite fission track dates of 12 11 ma across the nigde dome do not indicate that the metamorphic rocks were still on their way to the surface at that time instead they must reflect a later event which is most probably heating during late neogene magmatism lastly there is no ductile then brittle extensional detachment in the two areas where it has been invoked that is on the western and southern flanks of the dome an extensional detachment nevertheless exists at the top of the nigde dome best documented in its northern part where the detachment fault superposes a superficial unit made up of massive ophiolitic rocks onto the high grade metamorphic sequence field evidence indicates that this detachment developed before eocene times on the other hand our observations do not confirm the nonconformity of the sedimentary sequence dated as late maastrichtian late palaeocene onto the nigde high grade rocks field relations show either a tectonic contact between the two or the direct nonconformity of the eocene sediments onto the metamorphic rocks the lack of coarse clasts originating from the nigde high grade rocks within the maastrichtian palaeocene sequence further suggests that the metamorphic dome did not reach the surface before late palaeocene times these results compare well with available data from the northwestern part of the central anatolian crystalline complex suggesting that exhumation has been broadly synchronous on the scale of the massif as a result of an episode of high magnitude extension that affected the region in campanian to palaeocene times

experimental evidence for fluidization processes in breccia pipe formation results of small scale fiuidization spouting and channeling experiments suggest that similar processes may have been involved in the formation of many breccia pipe features various cylindrical parallel plate and boxlike model containers were filled with mixtures of particulate materials ranging from clay sized powdered kaolinitc to 1 cm gravel and each container was attached at its base to a large volume compressed air source features generated during the course of the various experimental runs are analogous to the majority of features observed in breccia pipes complex branching fracture systems developed in models containing abundant cohesive material appear to be similar to incipient crackle breccias steep walled funnel to cone shaped conduits formed readily and in some models inward dipping fractures ring fractures marginal shear folds and or downwarps and or high angle normal faults developed in adjacent material thorough mixing of heterogeneous particulate materials from throughout the stratigraphic column commonly was achieved and blocks of more cohesive materials were readily rounded and comminuted convective particle motion spouting was most effective in the mixing process and was accompanied by downwarping and fragmentation of adjacent strata downward migration of wall rock blocks along conduit margins and generation of annular zonation of conduit filling material in some systems annular size classification resulted in fine layering parallel to conduit walls crude centroclinally nested saucer bedding developed in some experiments where air fall ejecta were generated and these beds commonly were transported essentially intact downward within the pipe during a bubbling fiuidization event a gas streaming or channeling process in which finer material was elutriated or cleared out of coarser material led to the formation of channelways or chimneys which in natural systems would provide excellent avenues for introduction of later magma or hydrothermal solutions in model systems enriched in strongly cohesive clay sized particles accretionary pelletal spherules commonly were generated fluidization and related processes have been defined to describe highly controlled industrial systems problems of scale and strength of materials are significant when comparing experimental with geologic systems but the striking similarity of many features observed in both experimental and natural breccia pipe systems suggests that a similar genetic process is reasonable although many pipes clearly are not formed by fiuidization and related processes these processes may be important in the development of or some developmental stage of some breccia pipes

the east anatolian fault an oblique collisional belt abstract the tectonic setting for the area around the arabia africa anatolia triple junction is described from combined landsat spot satellite image analysis and field observations since the late miocene the motion along the east anatolian fault generated major structures corresponding to shortening with a sinistral slip component the 150 km wide area of the triple junction is highly deformed by folding and thrusting distributed mainly on the border of the anatolian block in addition kinematic reconstructions confirm that the arabia anatolia relative motion is both sinistral and convergent the sinistral strike slip faults of the east anatolian fault zone are of second order and local consequences of the n s arabia anatolia collision

engineering geological properties and durability assessment of the cappadocian tuff abstract some of the unique landforms the so called fairy chimneys which were formed within the cappadocian tuff of central turkey were used as dwellings in the past and contain culturally valuable wall paintings however these structures are undergoing chemical and physical deterioration due to atmospheric effects for conservation studies an understanding of the engineering geological properties of the tuff is essential in this study emphasis is placed on both material and mass properties of the tuff these properties are evaluated for the assessment of rock durability this study shows that the cappadocian tuff is almost fresh with local discoloration is moderately weak to very weak and has low unit weight very high porosity and high deformability discontinuity surveys revealed two dominant joint sets which not only controlled the formation but also control the structural stability of the fairy chimneys various methods used for the durability assessment of the cappadocian tuff indicate poor to very poor durability due consideration must be given to strength reduction due to moisture poor to very poor durability and the adverse effects of joints on the structural stability of the fairy chimneys

geotechnical and geoenvironmental characteristics of man made underground structures in cappadocia turkey underground cities and semi underground settlements most of which are 1500 years at least exist in the cappadocia region of turkey these man made rock structures are carved in soft tuffs and the best examples of long term performance of man made structures in the field of rock engineering the tuffs also have good thermal isolation properties to be used as housing and storage of foods in this article the authors are only concerned with physical and short term mechanical characteristics due to the wide spectrum of the theme and the in situ characterization of the cappadocia tuffs and the results of investigations are presented in addition a critical overview on possible engineering geological problems at cappadocia with mechanical aspects of historical and modern rock structures and their implications in rock engineering is made from the experimental results in the field it is evident that the engineering characteristics of these rocks do not show significant changes in vertical and horizontal directions however they are prone to atmospheric conditions in addition temperature and humidity measurements at different floors of the underground cities and various parts of semi underground settlements indicated that variations in climatic conditions of the openings are very small when compared to those outside the ground surface

acigol rhyolite field central anatolia part ii geochemical and isotopic sr nd pb δ18o constraints on volcanism involving two high silica rhyolite suites the acigol rhyolite field erupted the most recent high silica rhyolites within the cappadocian volcanic province of central anatolia turkey it comprises two sequences of domes and pyroclastic rocks with eruption ages of 150 200 ka eastern group and 20 25 ka western group compositionally the eastern rhyolite group lavas are less evolved sio2 74 76 wt whereas the western group has higher silica abundance sio2 77 wt with extremely depleted feldspar compatible trace elements within each group compositional variability is small and 143nd 144nd 0 51257 0 51265 and pb isotope compositions 206pb 204pb 18 87 18 88 207pb 204pb 15 65 15 67 and 208pb 204pb 38 94 38 98 are homogeneous the western group rhyolites have 18o zircon overlapping mantle values 5 7 0 2 whereas eastern group rhyolites are enriched in 18o by 0 5 consistent with a tendency to lower end values by contrast western group rhyolites have markedly more radiogenic 87sr 86sr ratios 0 7065 0 7091 compared to those of the eastern group 0 7059 0 7065 the presence of angular granitic xenoliths and a correlation between hydration based on loss on ignition data and 87sr 86sr in the western lavas however indicates that sr was added during the eruption or post eruption alteration isotope constraints preclude the possibility that the rhyolite magmas formed by partial melting of any known regional crystalline basement rocks basalts and andesites erupted in the periphery of the acigol field are characterised by 87sr 86sr ratios between 0 7040 and 0 7053 143nd 144nd 0 51259 0 51300 206pb 204pb 18 85 18 87 207pb 204pb 15 646 15 655 208pb 204pb 38 90 38 97 the isotopic and trace element data favour an origin of the rhyolites by mixing of basaltic andesitic magmas with minor amounts of crustal melts and followed by extensive fractional crystallization

on estimating length fluctuations of glaciers caused by changes in climatic forcing the reaction of alpine glaciers to shifts in the equilibrium line altitude ela is calculated by using a two dimensional numerical model to solve the full equations for the velocity and stress fields full system model in the absence of basal motion rates of advance and retreat of the snout of typically sized alpine glaciers are found to be insensitive to the details of the flow at the snout even when the glaciers are far from steady state a comparison of results obtained with a full system model and a shallow ice approximation sia model yields no significant differences in advance or retreat rates this assumption has been implicitly made in numerous previous climatic studies and is here shown to be well justified using a realistic mass balance altitude feedback only slight model dependent changes in steady state lengths are found the relative importance of mass balance and glacier dynamics for the transient response of alpine glaciers to changes in the ela is given a precise meaning by determining the model dependent additional shifts in ela needed for the sia and the full system models to produce identical changes in length for alpine glaciers these additional shifts in ela are on the order of 10 m which is within the error range of ela estimates it follows that at least in the absence of significant basal motion there is no need to include the effects of horizontal stresses when calculating the reaction of alpine glaciers to climatic changes attention should focus on accurate determination of the mass balance distribution and model tuning to give realistic ice thickness distributions

acigol rhyolite field central anatolia part 1 high resolution dating of eruption episodes and zircon growth rates protracted pre eruptive zircon residence is frequently detected in continental rhyolites and can conflict with thermal models indicating briefer magma cooling durations if scaled to erupted volumes here we present combined u th and u th he zircon ages from the acigol rhyolite field central anatolia turkey which is part of a quaternary bimodal volcanic complex unlike other geochronometers this approach dates crystallization and eruption on the same crystals allowing for internal consistency testing despite the overall longevity of acigol rhyolite volcanism and systematic trends of progressive depletion in compatible trace elements and decreasing zircon saturation temperatures we find that zircon crystallized in two brief pulses corresponding to eruptions in the eastern and western part of the field during middle and late pleistocene times respectively for late pleistocene zircon resolvable differences exist between interior average 30 7 0 9 ka 1 error and rim 21 9 1 3 ka crystallization ages these translate into radial crystal growth rates of 10 13 to 10 14 cm s broadly consistent with those constrained by diffusion experiments rim crystallization and u th he eruption ages 24 2 0 4 ka overlap within uncertainty evidence for brief zircon residence at acigol contrasts with many other rhyolite fields suggesting that protracted zircon crystallization in or recycling from long lived crystal mushes is not ubiquitous in continental silicic magma systems instead the span of pre eruptive zircon ages is consistent with autochthonous crystallization in individual small volume magma batches that originated from basaltic precursors

analyses of deterioration of the cappadocian tuff turkey the cappadocian tuff contains unique erosional features the so called fairy chimneys some of which in the past were dwelled in and contain valuable wall paintings these historical heritages however are undergoing chemical and physical deterioration due to atmospheric effects for the conservation studies understanding of the deterioration phenomenon of the tuff is essential in this study engineering geological and physicochemical characteristics of the tuff were determined the durability of the tuff was assessed through wetting drying freezing thawing and salt crystallization the test results suggest that chemical weathering may be traced to a depth of 2 cm below lichen covered surfaces and 20 cm adjacent to discolored joint walls based on durability assessment methods the tuff may be classified as having poor to very poor durability

a two dimensional analytic tidal model for a narrow estuary of arbitrary lateral depth variation the intratidal motion an innovative method is introduced to solve a two dimensional depth averaged analytic model for narrow estuaries or tidal channels with arbitrary lateral depth variations the solution is valid if the lateral variation of the amplitude of tidal elevation a is small i e a a where a is the amplitude of the tidal elevation this assumption is supported by a 60 day observation of elevation in the james river estuary using pressure sensors at both sides of a cross section of the estuary the error introduced by the solution is of the order of a a which has a maximum of 5 in the james river estuary the propagation of the tidal wave elevation is therefore essentially one dimensional along the estuary regardless of the depth distribution whereas tidal velocity has a strong transverse shear and is three dimensional in general dozens of depth functions in six groups of various forms are used to calculate the solution the tidal velocity is highly correlated with the bathymetry the largest amplitude of the along channel velocity is in the deepest water the phase of the along channel velocity in the shallow water leads that in deep water causing a delay in time of flood or ebb in the deep water the transverse velocity is generally small in the middle of a channel but reaches its maximum over the edges of bottom slopes the depth function has a significant effect on the ellipticity and the sense of rotation of the tidal ellipses by fitting the observed phase of semidiurnal tide in the james river estuary to the phase of the momentum equation we have obtained optimal values of the drag coefficient 1 5 10 3 and 1 8 10 3 for the spring and neap tides respectively then we apply these values of the drag coefficient and the model to the james river estuary using the real bathymetry results show remarkable agreement between the observations and the model along the transects for both spring and neap tides the cross channel phase difference of the along channel velocity between the channel and the shoal is found to be 1 hour a value consistent with that from the model the model estimated lateral variation of elevation is 2 5 of the tidal amplitude which is slightly smaller than the observed value

a new approximation in determination of zonation boundaries of ignimbrite by ground penetrating radar kayseri central anatolia turkey ground penetrating radar gpr method is used as a tool to identify the zonation boundaries in ignimbrite series through their columnar section ignimbrites can be classified in terms of welding degree colour texture and mineralogical compositions the research area comprises a part of incesu kayseri ignimbrite at central anatolia turkey this ignimbrite is divided into three levels and each level has clear differences in terms of macroscopic and microscopic views this paper presents the results of an application of gpr for the determination of zonation boundary within the ignimbrite flow unit in the view of their textural and petrological features ramac cu ii equipment was used with 250 mhz shielded antenna on parallel ten profiles to observe the physical difference among the ignimbrite levels of the study area two levels out of three have been defined at the incesu ignimbrite and supported by field geology and petrographical studies the first level which is extremely fractured structure is about 1 5 m thick and matches with middle level of the incesu ignimbrite the second level has an average 50 75 cm thickness and matches with lower level of the ignimbrite in this manner vertical lithological variations should be taken into consideration during petrological investigation of the ignimbrites

comments on monitoring soil erosion in cappadocia region selime aksaray turkey by yilmaz et al environ earth sci 2012 66 75 81 yilmaz et al 2012 presented a monitoring survey on soil erosion carried out around fairy chimneys of cappadocia region of turkey they scanned the study area by geodetic robotic total station at five different times and calculated the volume differences in order to find out the total erosion during that given time interval they finally analyzed the relationship between erosion and meteorological data and proposed that climatic conditions especially rainfall are an important eroding agent in the formation of this landscape whereas we welcome quantitative erosion surveys that are practically nonexistent in turkey the geological and geomorphological descriptions of the study area and scientific background contain vital mistakes that are totally unacceptable herein some important ones are commented upon although the aim of yilmaz et al s work is presented as the study of the role of erosion of the surrounding soil in the formation of fairy chimneys it is clear from their figs 1 and 4 where they show a photograph of the study area that their work does not deal with any soil formation but rather is an outcrop of eroding ignimbrite therefore the title of their work is misleading to say the least and do not represent their survey topic on the other hand even if we assume that the scanned area was covered by soil which we insist is not the case we are than entitled to question the use of such a method to measure the fairy chimneys erosion rates where no soil is involved during their formation during the description of their study area the authors state the region was formed sixty billion years ago it is common knowledge that the age of the earth is 4 54 0 05 billion years based on evidence from radiometric dating of meteorite material which is similar to the ages of the oldest known terrestrial and lunar rocks dalrymple 2001 we believe that the authors and the reviewers did not see this obvious mistake however even if we assume that they meant sixty million instead of sixty billion they are still very far away from the calculated age of the rocks in the area the reality is that the volcanism in cappadocia situated in central anatolian volcanic province cavp dates back to late miocene around 10 my my million years to holocene le pennec et al 2005 aydar et al 2012 fig 1 the authors scientific inconsistencies do not end on the formation age of the study area as they claim that all rocks forming fairy chimneys were produced by soft layers of lava and ash erupted from erciyes hasan and gullu volcanoes actually these three stratovolcanoes are mainly quaternary in age around 2 5 my aydar et al 1995 aydar and gourgaud 1998 kurkcuoglu et al 1998 en et al 2003 while the youngest ignimbrite layer kizilkaya ignimbrite that is known to form basin wide mesas in the region is 5 2 my of age le pennec et al 1994 aydar et al 2012 hence was emplaced well before the eruption of these volcanoes the stratigraphical framework of the region is very well established by several works where ar ar and u pb zircon ages between 10 and 5 2 my are proposed for the formation of the ignimbrites that are susceptible to form fairy chimneys pasquare 1968 innocenti et al 1975 a ciner geological engineering department hacettepe university ankara turkey e mail aciner hacettepe edu tr

mt pelee martinique may 8 and 20 1902 pyroclastic flows and surges abstract the distribution stratigraphic relationships and fragmental components of the may 8 and 20 1902 pyroclastic flows from mt pelee martinique together with eyewitness accounts suggest the following explanation for those eruptions the eruptions were vertically directed magmatic perhaps initiated phreatically and contained abundant juvenile lithics from congealed magma of the dome and neck this resulted in a two part eruption column having 1 a dense lithic charged part which collapsed into the crater and flowed out of a pre existing notch in its side giving rise to pyrochlastic flows and 2 a magmatically derived column containing gases juvenile vitric material and crystals which largely by passed the neck and dome and escaped into the atmosphere all of the energy of the flows was apparently focused through the notch they emerged fully turbulent and flowed down riviere blanche gravity segregation of large and abundant fragments soon resulted in a dense high concentration poorly fluidized block and ash flow confined to the valley leaving above a fully turbulent high energy ash cloud surge as the ash cloud surge moved down the mountain it continued to expand outward the process of gravity segregation continued as the ash cloud surge expanded resulting in secondary block and ash underflows toward st pierre the secondary block and ash flows developed on a gently sloping upland surface 100 m or more above the valley of riviere blanche the turbulent fragment depleted surges above the secondary block and ash flows maintained sufficient energy to devastate the landscape outward to about 3000 m including st pierre the surges refracted around obstacles and in one place moved up a small valley in a direction opposite to the main flows

field based experimental determination of the weathering rates of the cappadocian tuffs abstract since the last eruption in the cappadocia region that resulted in the formation of irregular hard thick lava layers on top of the cappadocian tuffs atmospheric processes have preferentially sculptured the tuffs the erosion processes have resulted in some beautiful topographical landscape features the so called fairy chimneys however erosion which is an important factor in the formation of fairy chimneys in the early stages has a negative effect on their future over time the number of visitors to this region has also increased and therefore in addition to natural erosion the effects of localized erosion resulting from tourism at the site have increased in the last few decades the physical mineralogical and mechanical properties of the cappadocian tuffs have been widely investigated in previous studies but their weathering characteristics particularly weathering rate were not determined in these studies determination of the weathering rate of these rocks is mandatory especially for conservation projects which should be urgently applied in order to protect this heritage in this study a comprehensive research program was carried out on the weathering properties of the cappadocian tuffs and the weathering rate was determined in field and laboratory investigations to this purpose a detailed field investigation was performed besides field observations the mineralogical physical and mechanical properties of tuffs were also determined in addition to durability evaluation by the slake durability index test wetting drying and freezing thawing tests were also performed for weathering rate assessment of the cappadocian tuffs in order to account for overburden load on some specific parts of pillars these wetting drying and freezing thawing tests were performed under loads the results obtained from field observations of old man made structures and from laboratory studies show that the weathering rate varies between 0 03 and 0 59 mm year for the esbelli tuff and 0 4 and 2 5 mm year for softer part of the kavak member

depositional mechanics of the 1902 pyroclastic nueeardente deposits of mt pelee martinique abstract pyroclastic flows are believed to have a rheology similar to other gravity mass flows such as turbidity currents avalanches or debris flows gravity plays a major role in controlling the mobility of a nuee ardente the paroxismal nuees being differentiated by their larger mass by the initial direction of the trajectory produced by the explosion and by their higher velocity the 1902 deposits of mt pelee accumulated from primary flows the deposits may be grouped into two different facies 1 a coarse grained thick bedded agglomerate that has characteristics similar to debris flow deposits and 2 a well stratified lapilli tephra and ash that has characteristics of turbidity current deposits these deposits result from two different types of flow generally laminar for the agglomerate and turbulent for the lapilli tephra and ash the maximum grain size used previously as an indicator of flow competence is valid for the traction load of the turbulent suspension but is unrealistically high for a true suspension load the coarsest size in the turbulent flow deposits probably did not travel in true suspension and a value of 5 on the cumulative distribution is more realistic for the evaluation of the shear velocity needed for true suspension although representing a maximum size application of the reynolds number criteria to the may 8 and 20 1902 nuees that destroyed st pierre indicates that turbulence is their only possible physical state in agreement with the observed characteristics of the deposits mean flow velocity of pure air necessary to support the 5 size in true suspension 140 984 m s 1 is unrealistically high however increasing the density at the base of the turbulent flow to 0 01 or 0 05 g cm 3 decreases the settling velocity of the grains significantly and brings the mean flow velocity needed to support all grains except the largest down to the observed values of the 1902 eruptions the larger grains require a higher mean flow velocity and or a higher density increasing flow density provides a reasonable answer to the suspension problem of the coarse fraction in turbulent nuees ardentes

characteristics of pyroclastic deposits at the margin of fond canonville martinique and implications for the transport of the 1902 nuees ardentes of mt pelee abstract the deposits which were studied at fond canonville represent a well defined record of the 1902 eruptions of the montagne pelee the sections are located at the margin of the valley where six eruption units with thicknesses ranging from 8 cm up to 2 m were identified overlying the pre 1902 paleosol the pyroclasts consist of lapilli coarse and fine ash composed of juvenile andesitic fragments of varying vesicularity dust free crystals dust free transparent vesicular glass and accretionary lapilli paleocurrent measurements on cross bedding support the stratigraphic evidence that the flows came down the valley of fond canonville rather than up as was previously proposed most eruption units are made of two or three beds always in sharp contact the basal bed relatively thin contains the coarsest grain size of the unit is massive or normally graded and fine depleted a thin division of parallel laminae may be present at the top the middle bed the thickest in all eruption units has a mean grain size which is intermediate between the lower and upper beds it may be simple or multiple normal grading is generally present on which may be superimposed in the upper portion of the bed 2 4 cm thick strata parallel to the upper bed surface or dipping from it at angles of less than 10 the upper bed the most regular in all units with thicknesses ranging from 2 to 8 cm is made of accretionary lapilli set in a matrix of fine ash a division of parallel and or oblique laminae is generally present at its top the characteristics of the deposits suggest that all three beds accumulated from a stratified turbulent flow normal grading of both coarsest and mean sizes sequences of internal structures including laminae evince that the flows were of relatively low concentration and that traction was an active process during the accumulation of the deposits for these structures to form the flows had to be turbulent for all three beds of the eruption units the thick strata superimposed on the graded middle bed are interpreted as having formed by the migration and aggradation of long wavelength antidunes the relationship between flow velocity and wavelength suggests that subaerial pyroclastic flows can only produce long wavelength antidunes with resulting internal stratification essentially parallel to bedding short wavelength antidunes in subaerial pyroclastic deposits require very high flow density at least close to the bed surface or low velocity which is unlikely considering the grain size present in the deposits

palaeomagnetism of the cappadocian volcanic succession central turkey major ignimbrite emplacement during two short miocene episodes and neogene tectonics of the anatolian collage abstract the central anatolian volcanic province in cappadocia includes 13 high volume calc alkaline ignimbrite sheets emplaced by plinian eruptions within a succession the urgup formation after 10 ma recording the last phase of neotethyan subduction and accompanying emplacement of the tauride orogen in southern turkey to evaluate magnetostratigraphy in the context of recent revisions of the chronostratigraphy we have extended palaeomagnetic investigation to 32 new sites yielding significant chrm directions integrated rock magnetic and palaeomagnetic investigations identify magnetic remanence residing predominantly in ti poor titanomagnetites although secondary processes within the ignimbrite sheets notably post emplacement oxidation have locally produced hematisation expressed by composite irm spectra and variable reduction in intensity of magnetisation the ignimbrite sheets possess weak anisotropies of magnetic susceptibility ams mostly 3 of pyroclastic deposits during polarity chron c4r 1n between 9 31 and 9 43 ma subsequent activity from the acigol centre further to the south west cemilkoy gelveri gordeles and kizilkaya produced in excess of 620 km 3 of pyroclastic deposits during polarity chrons between 5 3 and 7 1 ma the younger incesu ignimbrite was sourced in the sultansazligi pull apart basin to the east during the gauss chron 2 58 3 60 ma all pre incesu ignimbrites are rotated uniformly anticlockwise and the overall reversed group mean direction of magnetisation is d i 170 8 52 4 n 9 r 8 91 95 5 4 k 91 the implied tectonic rotation in this sector of central anatolia 16 4 relative to eurasia is young and postdates the 5 3 7 1 ma acigol centre whilst largely predating emplacement of the incesu ignimbrite whilst rotational deformation within anatolia is young it proves to be distributed with a temporal variation from block to block it is embraced by a complex post miocene tectonic regime of strike slip and extension during tectonic escape and suction towards the hellenic arc to the west

tertiary and quaternary volcanism of the erzurumkars area eastern turkey geochronological data and geodynamic evolution abstract this paper presents new geochemical and geochronological data on the neogene and quaternary volcanic products from the area of erzurum and kars eastern turkey the affinity of most of the volcanic rocks concerned is calc alkaline with the exception of minor quaternary alkaline rocks that outcrop in the kars sector ages range from 8 m y to 1 3 m y the time space distribution of the calc alkaline volcanism in eastern turkey nw iran is characterized by a sudden northward jump that occurred around 6 m y ago from the van erzurum southern belt to the kars northern belt available data indicate that this northward migration of volcanism was due to changes in the subduction geometry of the arabian plate under eurasia

the eurasian arabian and african continental margin from iran to greece the continental margin between eurasia and arabia can be traced as a continuous thrust zone for c 2000 km from the gulf of iran westwards through iran and turkey towards the mediterranean sea in this sector it forms a coherent geological whole with increasing structural complexity from s to n across the junction this clarity is terminated 125 km ne of the gulf of iskenderun on the mediterranean sea by the n s trending levant fault system lfs w of the lfs for 1400km to the w of greece the boundary significantly changes to curved micro plates which are not directly observable as they are beneath the sea their location is in doubt for c 650 km from the lfs westwards to the eastern margin of the aegean plate at the anaximander mountains over this sector several major tectonic units occur which obscure and complicate such a margin to the w the aegean plate continues for 750 km with the characteristics of an island arc

seismotectonics of the southern boundary of anatolia eastern mediterranean region subduction collision and arc jumping the pattern of seismicity and fault plane solutions of earthquakes are used to outline the tectonic features of the southern boundary of anatolia in the eastern mediterranean and southeastern turkey the results of this study show that this boundary is composed of two distinct parts one in southeastern turkey and syria is a wide and complex zone of continental collision the other in the levantine basin of the eastern mediterranean is a zone of oceanic subduction in the region of continental collision three zones of seismicity are observed most of the seismic activity in this region follows the bitlis zone and is associated with a zone of thrusting and mountain building this appears to be the zone of most active deformation and plate consumption in the plate boundary region between arabia and turkey a less active zone of seismicity to the north of the bitlis zone is interpreted to have been more active in the past whereas another active zone of seismicity to the south is interpreted to be a zone which may be more active in the future as the main zone of plate consumption jumps to the south in the subduction zone of the eastern mediterranean the depth of the subducted slab and the rate of seismicity generally increase from east to west the zone of present day convergence between africa and turkey in the levantine basin can be best outlined by the northern edge of the mediterranean ridge the subduction zone in this area sequentially jumps to the south as small continental fragments collide with existing zones of subduction deep seismic activity near the gulf of antalya is associated with a detached subducted slab north of the anaximander mountains that is distinctly different from the seismic trend which is associated with present day active subduction the plate boundary between africa and turkey at the center of the levantine basin appears to have shifted to the south of the anaximander mountains and florence rise most of the focal mechanisms of the earthquakes along the entire southern boundary of anatolia indicate that n to nnw thrusting is the dominant mode of seismic deformation the present set of data is inconsistent with a major transform fault in the cyprean arc east of cyprus and in southeastern turkey

geochemical approach to magmatic evolution of mt erciyes stratovolcano central anatolia turkey erciyes stratovolcano culminating at 3917 m is located in the cappadocian region of central anatolia during its evolution this quaternary volcano produced pyroclastic deposits and lava flows the great majority of these products are calc alkaline in character and they constitute kocdag and erciyes sequences by repeated activities alkaline activity is mainly observed in the first stages of kocdag and approximately first middle stages of erciyes sequences generally kocdag and erciyes stages terminate by pyroclastic activities the composition of lavas ranges from basalt to rhyolite 48 4 70 5 wt sio calc alkaline rocks are represented mostly by andesites and dacites some compositional 2 differences between alkaline basaltic basaltic and andesitic rocks were found while the composition of dacites remain unchanged all these volcanics are generally enriched in lil and hfs elements relative to the orogenic values except rb ba nb depleted alkaline basalt 87 srr 86 sr and 143 ndr 144 nd isotopic composition of the volcanics range between 0 703344 0 703964 0 512920 0 512780 for alkaline basalts and change between 0 704322 0 705088 0 512731 0 512630 for alkaline basaltic rocks whereas calc alkaline rocks have relatively high sr and nd isotopic ratios 0 703434 0 705468 0 512942 0 512600 low rb ba nb content with high zrrnb low barnb laryb ratio and low sr isotopic composition suggest an depleted source component while high ba rb nb content with high laryb barnb low zrrnb and low 87 srr 86 sr ratios indicate an oib like mantle source for the generation of erciyes alkaline magma these elemental and ratio variations also indicate that the different mantle sources have undergone different degree of partial melting episodes the depletion in ba rb nb content may be explained by the removal of these elements from the source by slab derived fluids which were released from pre collisional subduction modified the asthenospheric mantle the chemically different mantle sources interacted with crustal materials to produce calc alkaline magma the barnb increase of calc alkaline samples indicates the increasing input of crustal components to erciyes volcanics sr and nd isotopic compositions and elevated lil and hfs element content imply that calc alkaline magma may be derived from mixing of an oib like mantle melts with a subduction modified asthenospheric mantle and involvement of crustal materials in intraplate environments q 1998 elsevier science b v all rights reserved

asymmetric tidal straining across an inlet lateral inversion and variability over a tidal cycle abstract tidal straining is a phenomenon of temporal variations in stratification and mixing resulting from the interaction of a longitudinal salinity gradient with the vertical shear of the horizontal tidal velocity as a result the theory predicts stronger and weaker stratification during ebb low tide and flood high tide respectively in contrast to this well known temporal asymmetry in this study we document in situ measurements demonstrating a lateral asymmetry and lateral inversion of tidal straining at barataria pass a narrow 600 m wide tidal inlet of barataria bay in southeastern louisiana during flood the eastern side of the channel had strong stratification of 4 psu salinity change over a 1 5 m thin layer while the western side had a 2 psu change over a 12 m water column this strong lateral difference decreased as flood continued until near the end of the flood when it reached vertically well mixed condition across the channel during ebb it was just the opposite such that the western side became stratified while the eastern end was well mixed this resulted to a small correlation coefficient of 0 05 for stratification between the west and east sides although the central channel and east side have a high correlation coefficient of 0 88 the tidally averaged salinity was higher on the western end than the eastern end except in a narrow boundary layer close to the eastern shore this is an apparent contradiction to what the coriolis effect would produce in classical estuarine dynamics our hypothesis for the observed difference arises from the influence of the river water coming out of the mississippi river through the southwest pass of the birdfoot delta this water mass may have played a role in the observed complicated lateral inversion of the tidal straining this study underlines the complexity of estuarine dynamics proximal to large deltaic systems and we anticipate that these results will underscore the need for a modeling study to further investigate this dynamic process

inference of tidal elevation in shallow water using a vessel towed acoustic doppler current profiler vessel towed acoustic doppler current profilers adcps have been widely used to measure velocity profiles since the instrument is usually mounted on a catamaran floating on the surface previous studies have used the water surface as the reference level from which the vertical coordinate for the velocity profile is defined however because of the tidal oscillation the vertical coordinate thus defined is time dependent in an earth coordinate system which introduces an error to the estimated harmonic constants for the velocity as a result the total transport will also be in error this is particularly a problem in shallow waters where the tidal elevation is relatively large therefore tidal elevation needs to be resolved to make a correct harmonic analysis for the velocity the present study is aimed at resolving the tidal elevation change in shallow water using a vessel towed adcp semidiurnal and diurnal tidal elevations across the lower chesapeake bay have been determined using a vessel towed adcp data from four cruises ranging from 25 to 92 hours in 1996 and 1997 are used water depth averaged every 30 s by the adcp is studied by harmonic and statistical analysis by selecting only the data within a narrow band 320 m over the planned transect we are able to improve the reliability of the data we then grid the depth data along the 16 km transect into 200 equal segments and use harmonic analysis to resolve the semidiurnal and diurnal tidal variations within each segment we find that 1 the depth data from the adcp contain both semidiurnal and diurnal signals that can be resolved from which the surface elevation can be inferred 2 the major error appears to come from spatial variation of the depth 3 the semidiurnal and diurnal tidal variations of elevation inferred over flat bottom topography account for almost 100 of the total variability while those measurements over large bottom slopes account for a much lower percentage of the total variability 4 at least 70 of the variability of depth can be explained by semidiurnal and diurnal tides if the bottom slope is smaller than 0 006 and 5 the spatial variation of both amplitude and phase of the elevation along the transect appears to be small with a slightly lower tidal amplitude at the south of the chesapeake bay entrance consistent with the coriolis effect the inferred elevations from the adcp readings are consistent with sea level measurements at a tide station 10 km inside the estuary

an attempt to use aerial gamma ray spectrometry results in petrochemical assessments of the volcanic and plutonic associations of central anatolia turkey summary volcanic and magmatic rocks of central anatolia are fairly rich in radioelement concentrations the aerial gamma ray spectrometric survey data gathered for the purpose of radioactive mineral exploration were utilized as an additional tool for the petrochemical classification of the volcanic and magmatics rocks and their environments the survey data on acidic intrusions e g granite monzonite and syenite have revealed radioelement concentrations to occur in wide ranges to be 2 6 wt per cent for potassium k 3 15 ppm for uranium u and 10 52 ppm for thorium th the chain like high and moderately high potassium uranium and thorium anomalies on acid intrusives of the entire area show a halo shaped feature locations and lithological compositions of the volcanic rocks namely lavas tuffs ignimbrites and basalts appear to be reasonably effective on their radioelement concentrations the highest potassium uranium and thorium concentrations of the volcanic rocks are around 4 wt per cent 10 ppm and 35 ppm respectively consequently depending on the location and composition volcanics show a very wide range of air absorbed dose rate the lowest rates which vary between 10 and 120 ngy hr were calculated in the ophiolitic group thick cultivated soil covering areas particularly at the centre of the aerial survey area metamorphosed rocks in the north and young basalts mostly in the kayseri district their average radioelement concentrations were found to be very low that is 1 2 wt per cent 2 3 ppm and 10 ppm for k u and th respectively because of the accumulation of soluble uranium isotopes air absorbed rates stemming from

active tectonics of the alpine himalayan belt between western turkey and pakistan summary over 80 new fault plane solutions combined with satellite imagery as well as both modern and historical observations of earthquake faulting are used to investigate the active tectonics of the middle east between western turkey and pakistan the deformation of the western part of this region is dominated by the movement of continental material laterally away from the lake van region in eastern turkey this movement helps to avoid crustal thickening in the van region and allows some of the shortening between arabia and eurasia to be taken up by the thrusting of continental material over oceanic type basement in the southern caspian mediterranean makran and black sea thus central turkey bounded by the north and east anatolian strike slip faults is moving west from the van region and overrides the eastern mediterranean at two intermediate depth seismic zones one extending between antalya bay and southern cyprus and the other further west in the hellenic trench the motion of northern iran eastwards from the van region is achieved mainly by a conjugate system of strike slip faults and leads to the low angle thrusting of iran over the southern caspian sea the seismicity of the caucasus shows predominantly shortening perpendicular to the regional strike but there is also some minor elongation along the strike of the belt as the causcasus overrides the caspian and black seas the deformation of the eastern part of this region is dominated by the shortening of iran against the stable borders of turkmenistan and afghanistan the north east direction of compression seen in zagros is also seen in north east iran and the kopet dag where the shortening is taken up by a combination of strike slip and thrust faulting large structural as well as palaeomagnetic rotations are likely to have occurred in ne iran as a result of this style of deformation north south strike slip faults in southern iran allow some movement of material away from the collision zone in ne iran towards the makran subduction zone where genuinely intermediate depth seismicity is seen within this broad deforming belt large areas such as central turkey nw iran azerbaijan central iran and the southern caspian appear to be almost aseismic and therefore to behave as relatively rigid blocks surrounded by active belts 200 300 km wide the motion of these blocks can usefully be described by poles of rotation the poles presented in this paper predict motions consistent with those observed and also predict the opening of the gulf of iskenderun ne of cyprus the change within the zagros mountains from strike slip faulting in the nw to intense thrusting in the se and the relatively feeble seismicity in se iran baluchistan this description also explains why the north south structures along the iran afghanistan border do not cut the east west ranges of the makran within the active belts surrounding the relatively aseismic blocks a continuum approach is needed for a description of the deformation even though motions at the surface may be concentrated on faults the evolution of fault systems within the active zones is controlled by geometric constraints such as the requirement that simultaneously active faults do not in general intersect many of the active processes discussed in this paper particularly large scale rotations and lateral movement along the regional strike are likely to have caused substantial complexities in older mountain belts and should be accounted for in any reconstructions of them

the 1902 peleean deposits in the fort cemetery of st pierre martinique a model for the accumulation of turbulent nuees ardentes abstract the ancient fort cemetery located at the northwestern limit of st pierre has been left undisturbed since 1902 and therefore offers a unique opportunity to study the deposits of the eruptions that destroyed the city six eruption units were found overlying the floor of the cemetery leaving an average 1 6 m thick deposit the city was hit by four major nuees which occurred on may 8 20 june 6 and august 30 the may 20 and june 6 eruption units are each made of three beds the basal bed always lacks fines and is generally massive the middle bed is normally graded on which dune type cross bedding is superimposed in the may 20 deposit the upper bed the thinnest has the finest grain size of the eruption unit and is normally graded true parallel laminae were only observed in the upper bed the may 8 eruption unit is essentially made of fines depleted massive lapilli and tuff the evidence strongly suggests that the deposits of the middle and upper beds accumulated from turbulent suspensions the absence of structures in the basal bed is not conclusive evidence of laminar flow deposition and its characteristics are similar to deposits that have accumulated from highly concentrated turbulent suspensions the lack of fines observed only in the basal bed is attributed to gravity segregation helped by vaporization of water present in the underlying deposits and for the may 8 deposit to escaping gas produced by the destruction of the vegetation during or immediately after deposition which could explain the absence of primary structures in the basal bed the fine grained deposits of mt pelee show a primary structure sequence similar to the turbidite sequence and are therefore interpreted in terms of decreasing flow velocity and grain size with time at a fixed site

flow dynamics of tidewater glaciers a numerical modelling approach the dynamics of grounded tidewater glaciers is investigated with a time dependent numerical flow model which solves the full equations for the stress and velocity fields and includes a water pressure dependent sliding law the calving criterion implemented in the model shifts the calving front at each time step to the position where the frontal ice thickness exceeds flotation height by a prescribed value with this model the linear relation between calving rate and water depth proposed on empirical grounds is qualitatively reproduced for the situation of a slowly retreating or advancing terminus but not for situations of rapid changes length changes of tidewater glaciers i e especially rapid changes are dominantly controlled by the bed topography and are to a minor degree a direct reaction to a mass balance change thus accurate information on the near terminus bed topography is required for reliable prediction of the terminus changes due to climate changes the results also confirm the suggested cycles of slow advance and rapid retreat through a basal depression rapid changes in terminus positions preferably occur in places where the bed slopes upwards in the ice flow direction

building a tephrostratigraphic framework for the paleolithic of central anatolia turkey the central anatolian volcanic province cavp in turkey preserves widespread deposits of quaternary tephra presently associated with a small but growing number of paleolithic archaeological sites we use multivariate analyses of the abundances of a suite of nine major and minor element oxides determined by electron probe microanalysis from these data we construct a classificatory model for correlating distal tephra to one of five volcanic edifices or eruptive phases within the cavp application of this model to distal deposits of primary tephra fall and reworked tuffaceous sediments from the archaeological sites of korkuyu and kaletepe deresi 3 indicates late to possibly early pleistocene ages for the artifact assemblages there and provides a fundamental tephrostratigraphic framework to examine spatial and temporal variation in hominin behavior comparable to that of other regions such as eastern africa

the role of fractional crystallization magma recharge and magma mixing in the differentiation of the small hasandag volcano central anatolia turkey abstract during the last 7 ma eruptions of the small hasandag composite volcano in central anatolia turkey have produced calc alkaline lavas ranging in composition from basalt to rhyolite published research on this volcano suggests that crystal fractionation and magma mixing are the two important processes controlling the differentiation of the small hasandag magmas the shortcomings of previous studies are that neither the intensive variables p t fo2 nor the constraints under which the presumed parental magmas evolved have been quantitatively evaluated in this study we have used the melts algorithm of ghiorso and sack 1995 to determine the initial system parameters in terms of temperature t pressure p oxygen fugacity fo2 and water content wt h2o and then evaluated the consequences of magma differentiation under closed system fractional crystallization magma recharge and magma mixing conditions separately in order to determine the initial system parameters we carried out approximately 100 isobaric fractional crystallization simulations of the parental basaltic andesite magma mg 68 in the pressure range of 1 bar to 10 000 bars an fo2 range of qfm 1 to qfm 3 and at water contents from 0 to 4 wt the best agreement between the computed melt compositions and the natural rocks was achieved at p 1000 bars fo2 qfm 1 and 2 wt water computations with parental basaltic andesite at these initial system conditions and under isobaric fractional crystallization generated melt compositions from basaltic andesite to dacite that are very similar to observed lava compositions compositions more evolved than dacites however cannot be produced by closed system fractional crystallization alone this is because rhyolites generated by closed system fractional crystallization have total alkali na2o k2o values lower than those of the small hasandag rhyolites furthermore natural rock compositions in the silica range of 62 65 wt show discrete cycles of sudden increase and decrease in the mgo content in the range of 0 5 1 wt suggesting magma replenishment this study shows that fractional crystallization and magma recharge in the composition range of basaltic andesite to dacite followed by isobaric isenthalpic mixing of dacite with the most differentiated rhyolite mg 46 generate melt compositions that most closely resemble the entire compositional range of the small hasandag lavas including the rhyolites the agreement between the liquid line of descent defined by the natural lavas and melts calculations and the agreement between the observed mineralogy of the rocks and the calculated order of crystallization support this conclusion

le volcanisme quaternaire d anatolie centrale turquie association de magmatismes calco alcalin et alcalin en domaine de convergence collision volcanism in central anatolia cappadocia began at least in the late miocene because of the north south arabian eurasian convergence since this period the anatolian block is displaced towards the west along the north and east anatolian strike slip faults kinematic reconstructions show that the east anatolian fault is both sinistral and convergent as a consequence the anatolian block is currently being deformed quaternary volcanism in central anatolia is represented by several hundreds of monogenetic scoria cones lava flows maars and domes as well as two strato volcanoes hasan dag and erciyes dag the monogenetic volcanism is bimodal basalts and rhyolites whereas the stratovolcanoes exhibit a complete calc alkaline suite from basalts to rhyolites most of the igneous products are calc alkaline basalts erupted mainly from the monogenetic cones lava flows and maars andesites are encountered in the strato volcanoes as lava flows domes and nuees ardentes deposits dacites and rhy

deformation of poorly consolidated sediment during shallow emplacement of a basalt sill coso range california a 150 m long wedge shaped unit of folded and faulted marly siltstone crops out between undeformed sedimentary rocks on the north flank of the coso range california the several meter thick blunt end of this wedge abuts the north margin of a basaltic sill of comparable thickness chaotically deformed siltstone crops out locally at the margin of this sill and at one locality breccia pipes about one meter in diameter crosscut the sill the sill extends about 1 km south up the paleoslope where it merges through continuous outcrop with a lava flow that in turn extends 1 4 km to a vent area marked by more than 100 m of agglutinate and scoria apparently lava extruded at this vent flowed onto unconsolidated sediments burrowed into them and fed a sill at about 40 m depth within the sedimentary sequence the sill initially propagated by wedging between sedimentary beds but eventually began to push some beds ahead of itself forming a remarkable train of folds in the process the sediments apparently were wet at the time of sill emplacement because hydrothermal alteration is common near the contact between the two rock types and because the breccia pipes that crosscut the sill apparently resulted from phreatic explosions of pore water heated at the base of the cooling sill comparison of deformation of the host material at the coso locality with that reportedly caused by emplacement of sills elsewhere indicates that the character of deformation differs greatly among the various localities the specific response of host material depends upon such parameters as initial properties of magma and host material rate of sill growth and attendant rate of strain of host material and depth of sill emplacement some properties may change considerably during an intrusive deformational episode thus complicating accurate reconstruction of such an event

fairy chimney erosion rates on cappadocia ignimbrites turkey insights from cosmogenic nuclides abstract cappadocia in the central anatolian plateau of turkey is famous for its unique landscape and unusual rock formations the development of this landscape dates back to late miocene epoch c 10 million years when volcanoes spread pyroclastic deposits over an area of about 20 000 km 2 the volcanism continued for several millions of years and laid down thick and colorful ignimbrite layers the evolution of the cappadocian landscape starts with nearly horizontal plateaus which are then dissected usually along cooling fractures to form mushroom like structures hoodoos locally known as fairy chimneys different layers of ignimbrites have different resistance to erosion softer layers necks are easier to erode compared to the harder ignimbrites caps when the chimneys are isolated the caps play an important role in slowing further erosion of softer layers when the caps finally drop or completely erode away the soft necks of the chimneys are quickly destroyed here for the first time we have determined the bedrock erosion rates at the three evolution stages of fairy chimneys using the cosmogenic chlorine 36 36 cl the pre chimney plateaus stage the chimney stage and the post chimney stage the data show that the plateaus erode at a very low rate between 0 58 0 02 cm ky and 0 93 0 05 cm ky when dissection of a plateau starts the erosion rate increases to about 4 5 0 6 cm ky the caps of chimneys have erosion rates between 3 21 0 36 cm ky and 3 39 0 36 cm ky once the chimneys disappear erosion rates increase significantly to 28 0 9 9 cm ky

late cenozoic tectonics and volcanism along the north anatolian fault new structural and geochemical data abstract different types of volcanic activity have developed along the north anatolian fault zone naf in turkey detailed analysis of satellite images and digital elevation models dems and field observations have been made in order to understand the tectonics and the distribution of volcanic vents in the anatolian block some faults are oblique to the naf and delimit extensional escape wedges vents rooted on open tension fractures show that emplacement of the volcanism is related to tensional fracturing of the anatolian continental block which we attribute to the onset of free borders in the south and west along the naf earliest extension 1 is directed s to ssw and the latest 2 towards w to wsw parallel to the sinistral slip along the naf major and trace element geochemical data indicate that the dominant calc alkaline rocks are associated with various alkaline lavas k ar ages of the volcanics range from 22 to 8 5 ma in galatia massif 900 to 100 ka in niksar and 3 to 12 ka in erzincan isotopic and trace element data are interpreted as reflecting a dominantly lithospheric mantle source slightly mixed with asthenospheric liquids most magmas were fractionated and contaminated by continental crust during their ascent 1 and 2 tectono volcanic events have propagated through time and space from west to east the 1 extension is late oligocene in the galatia massif late miocene in niksar and late pliocene in erzincan the 2 extension and strike slip event along the naf began in the late miocene in the galatia massif early pliocene in niksar and quaternary in erzincan signature from an asthenospheric source in the second event in the three regions suggests that an ancient suture zone galatia massif and or the lithospheric naf transform niksar and erzincan have served to channel small quantities of asthenospheric melts existing at the base of the lithosphere

the geology of mount hasan stratovolcano central anatolia turkey mount hasan is a double peaked stratovolcano located in central anatolia turkey the magmas erupted from this multi caldera complex range from basalt to rhyolite but are dominated by andesite and dacite two terminal cones big mt hasan and small mt hasan culminate at 3253 m and 3069 m respectively there are four evolutionary stages in the history of the volcanic complex stage 1 kecikalesi volcano 13 ma stage 2 palaeovolcano 7 ma stage 3 mesovolcano and stage 4 neovolcano the eruptive products consist of lava flows lava domes and pyroclastic rocks the later include ignimbrites phreatomagmatic intrusive breccias and nuees ardentes sometimes reworked as lahars the total volume is estimated to be 354 km 3 the area extent 760 km 2 textural and mineralogical data suggest that both magma mixing and fractional crystallization were involved in the generation of the andesites and dacites the magmas erupted from the central volcanoes show a transition with time from tholeite to calc alkaline three generations of basaltic strombolian cones and lava flows were emplaced contemporaneously with the central volcanoes the corresponding lavas are alkaline with a sodic tendency

flow convergence and stability at a tidal estuarine front acoustic doppler current observations characteristics of the flow field in an estuarine frontal zone have been investigated in a field study in the lower james river estuary underway sampling with an acoustic doppler current profiler adcp on repeated transects across the front provided information on the structure of the flow field near the front and its evolution in time as this tidal intrusion front advanced up the estuary during the flooding tide prominent and consistent features in the velocity field included a localized zone of convergent flow beneath the visible surface line and a stratified shear layer just upriver of the front within the shear layer between the buoyant surface water and the faster higher salinity undercurrent gradient richardson number estimates suggest that the flow was at or near the threshold for shear instability another shear type gradient in the flow field the across front variation of the along front velocity component strengthened over a sequence of transects with intensity increasing toward the surface tracking of the front was then interrupted when the identifying line of foam and accumulated material on the surface previously sharp and well defined broke up and dispersed to such an extent that the visible signature of the front was lost temporarily a visible frontal expression later reappeared and propagation upriver continued lower bound estimates of downwelling flow in the frontal zone were determined by continuity considerations

a study of non linear tidal propagation in shallow inlet estuarine systems part i observations the offshore tide becomes strongly distorted as it propagates into shallow estuarine systems observations of sea surface elevation and horizontal currents over periods ranging from three days to one year at nine stations within nauset inlet estuary document the non linear interaction of the off shore equilibrium tidal constituents despite strong frictional attenuation within the estuary the overtides and compound tides of m2 s2 and n2 in particular reach significant amplitude resulting in strong tidal distortion high frequency forced constituents in sea surface are phase locked consistently leading the forcing tides by 60 70 resulting in a persistent distortion where falling tide is longer than rising tide forced constituents in currents are more nearly in phase with equilibrium constituents producing flood currents which are shorter but more intense than ebb currents a compound fortnightly tide msf modulates the mean water level such that lowest tides occur during neap phase instead of spring phase this fortnightly tide can be contaminated by storm surge changing the phase characteristics of this constituent implications of the overtides compound tides and lower frequency tides on near bed suspended and dissolved material transport are profound

summertime tidal flushing of barataria bay transports of water and suspended sediments the edges of the inlet the net flux of total suspended sediment out of the bay was determined to be 8800 t of which 20 was organic matter demonstrating a significant source of organic matter to the base of the coastal ocean detrital food chain the time evolution and net fluxes of water and suspended sediments showed that the net flow resembles conventional estuarine circulation patterns with net outward flow on the surface and shallow ends of the inlet and with net inward flow in the center and at the bottom of the center of the inlet the west side has a much larger outward flow than the east side while the east side is fresher these differences suggest that the louisiana coastal current from around the bird s foot delta derived from the mixing of shelf water with the mississippi river freshwater may have entered the bay this must have been mostly from the east side during the survey which resulted in a smaller outward flow on the eastern side a numerical experiment further confirmed this assumption and the model was verified by field observations on 5 may 2010

three dimensional s wave structure of the upper mantle beneath turkey from surface wave tomography summary a 3 d upper mantle structure beneath turkey is investigated using phase speeds of fundamental mode rayleigh waves employing a conventional two station method with high density seismic networks in turkey we analyse 289 seismic events with moment magnitude 5 5 and greater and with focal depth shallower than 100 km between 2006 and 2008 waveform data are derived from 164 three component broad band seismic stations operated by two national seismic networks at first rayleigh wave phase speed maps are obtained from the inversion of two station phase speeds using about 1000 3000 paths depending on the period of rayleigh waves the three dimensional s wave model is then obtained in the depth range from 40 to 180 km using the phase speed maps in the period range from 25 to 120 s our model reveals the fast anomalies in the north of cyprus associated with the subducted portion of the african oceanic lithosphere from the cyprus trench we identify a vertical discontinuity of the fast anomaly associated with the cyprus slab starting at 60 80 km depth which may represent a minor tear of the cyprus slab we observed that the western part of the cyprus slab is getting closer to the edge of the hellenic slab beneath the isparta angle ia and antalya basin our model also indicates a slow wave speed anomaly beneath the ia and antalya basin probably due to hot materials of asthenosphere rising from a tear of the subducted african oceanic lithosphere that is a slab tear between the cyprus and the hellenic subductions in the eastern part of turkey a widespread slow anomaly appears in the model that corresponds to the eastern anatolian accretionary complex eaac our model shows a fast anomaly beneath the eaac that can be interpreted as the detached portion of the subducted arabian lithosphere

late pleistocene eruptive recurrence in the post collisional mt hasan stratovolcanic complex central anatolia revealed by zircon double dating abstract mt hasan 3262 m is the second highest stratovolcano in central anatolia turkey and is considered active based on a ca 9 ka explosive summit eruption that was arguably depicted in a neolithic mural at the nearby catalhoyuk archaeological site besides evidence for holocene activity of mt hasan its eruptive chronostratigraphy and hazard potential remain poorly constrained here we apply u th he thermochronology in combination with u th pb crystallization ages zircon double dating including a novel population based approach to disequilibrium correction of u th he data in an attempt to determine the eruption ages of strategically sampled lavas and pyroclastic deposits and to refine the late pleistocene chronostratigraphy of mt hasan during the late pleistocene mt hasan erupted multiple interfingering andesitic lava flows along with block and ash flows seven of these lava flows typically the stratigraphically youngest in a particular segment around the two central vents of the volcano yielded late pleistocene eruption ages between 91 9 3 9 and 18 1 2 4 ka uncertainties stated at 1 an even younger block and ash flow was deposited on the western flank of the volcano at 13 5 1 5 ka which together with a ca 9 ka small volume explosive summit eruption define the youngest activity at the main edifice of mt hasan collectively these data indicate a late pleistocene recurrence of at least one eruptive phase every ca 5 15 ka new volume estimates for the quaternary edifice of 130 180 km3 translate into an integrated long term eruptive magma flux of 0 3 km3 ka which is just slightly higher than late pleistocene flux estimates based on lava flow geochronology and volumes determined by analysis of digital elevation models this long term eruptive flux estimate is similar to those of stratovolcanoes in continental arcs indicating that eruptive productivity in post collisional settings can match that of active continental margins all mt hasan eruptions including the holocene event sampled zircon which crystallized coeval with earlier eruptive phases indicating longevity of the magma plumbing system along with ongoing fumarole activity and evidence for mid crustal low seismic velocity zones this suggests that a subvolcanic magma reservoir remains active to the present day

palaeomagnetism and magnetic properties of the cappadocian ignimbrite succession central turkey and neogene tectonics of the anatolian collage abstract the cappadocian ignimbrite succession of central southern anatolia comprises at least nine major and two minor calc alkaline rhyolitic sheets emplaced at 1 2 ma intervals between 11 2 and 1 1 ma it records the last phase of neotethyan subduction during final emplacement of the tauride orogen in southern turkey this study reports magnetostratigraphy and describes associated rock magnetic properties remanence resides in ti poor titanomagnetites haematisation is locally produced by post emplacement oxidation but does not contribute significantly to the palaeomagnetic signature although secondary processes within the ignimbrite sheets have produced composite isothermal remanent magnetisation spectra and variable intensities of magnetisation weak anisotropy of magnetic susceptibility describes tensors with maximum axes close to bedding and minimum axes perpendicular to this plane directions of kmax with weak imbrication mostly suggest flow away from centres of eruption located by gravity and remote sensing older ignimbrites upper and lower goreme akdag zelve from the cardak centre are all of normal polarity later ignimbrites partly erupted from the derinkuyu centre comprise the sarimaden r cemilkoy r tahar r kizilkaya r incesu n and valibaba sofular r ignimbrites the overall reversed group mean is d i 174 51 n 10 units r 9 84 95 6 6 k 55 and all magnetisation directions from the upper goreme 9 0 ma onwards are rotated anticlockwise with respect to eurasian and african palaeofields this sense of rotation characterises most of central anatolia and averages 9 5 in this sector the rotation rate from 8 to 1 ma bp was 1 25 ma but it appears to have accelerated during the latter part of the quaternary to about an order higher than rates determined from gps rotation has resulted from extrusion of fault blocks during tectonic escape of the anatolian collage to the southwest and followed crustal thickening as the afro arabia plate has continued to impinge differentially into eurasia cenozoic magnetic inclinations are systematically shallower across anatolia than inclinations expected from the geocentric dipole model and the apparent polar wander of bordering major plates only part of this difference 400 km can be accommodated by northward movement and crustal thickening in central anatolia since mid miocene times shallow inclinations observed in the aegean region extend into turkey they are observed in young volcanics and appear to reflect a regional geomagnetic anomaly the pattern of neotectonic declinations across anatolia shows rotations that are strongly anticlockwise rotated in the east near the arabian pincer but diminish towards the west to become zero or slightly clockwise at the western extremity of the collage rotations also seem to become generally younger towards the south crustal deformation has therefore been distributed and the net effect of terrane extrusion to the west and south has been to expand the curvature of the tauride arc and by inference the cyprus arc

mapping of tide and tidal flow fields along a tidal channel with vessel based observations 1 we present the results of a study focused on the tidal regime of a shallow channel with a large intertidal area data from a vessel towed acoustic doppler current profiler adcp were used to infer tidal constituents for both tidal elevation and tidal current along an upstream portion of the okatee river south carolina the tidal elevation is estimated from the depth recorded by the moving adcp this tidal elevation is then used to correct the vertical coordinates of each depth bin below the adcp for the velocity profiles the ability to resolve both tidal elevation and velocity allows us to determine that the tide is a standing wave a statistical analysis demonstrates that the along channel velocity has a stronger tidal signal larger r2 values than the across channel velocity when only the m2 and mean components are included in the harmonic analysis about 75 of the covered area along the ship track has a good fit where at least 70 of the variability can be explained by the tidal and mean components by adding the m4 component to the harmonic analysis an additional 2 of the covered area has good fit for the elevation depth averaged velocity and mid depth velocity but 12 for the near surface velocity the observed spatial distribution of the residual flow is in reasonable agreement with that predicted by an unstructured grid finite volume coastal ocean model fvcom

correlation of ignimbrites in the central anatolian volcanic province using zircon and plagioclase ages and zircon compositions abstract episodes of high eruptive fluxes 10 3 km 3 year in continental environments are associated with magmatism related to subduction post orogenic collapse intra plate hot spots or rifting during such episodes voluminous ignimbrite deposits are produced which cover landscapes over 10 4 10 5 km 2 in such sequences brief eruptive recurrence and chemical similarity limit the applicability of geochronological and geochemical correlation methods here we present complementary geochronological data 40 ar 39 ar plagioclase eruption and 206 pb 238 u zircon crystallization ages for ignimbrites from the miocene holocene central anatolian volcanic province cavp in addition we successfully employed zircon geochemistry trace elements oxygen isotopes as an alteration resistant indicator to correlate rhyodacitic to rhyolitic ignimbrites whose eruption age differences are too brief to be resolved by 40 ar 39 ar geochronology by applying this method we dismiss previous correlations between stratigraphic members i e sofular and gordeles sofular and sarimadentepe but demonstrate close relationships for other cavp ignimbrites i e kavak units 1 to 4 cemilkoy ignimbrite and overlying fallout deposits our chronostratigraphy reveals two previously unrecognized eruptive pulses at 9 8 ma and 7 5 ma which are characterized by increasing magmatic temperatures 75 100 c within each cycle despite a long term 10 ma eruptive productivity that is about one order of magnitude smaller than in other magmatically active continental plateaus the cavp achieved high eruptive fluxes during brief 1 2 ma intervals

continental arc volcanism and tectonic setting in central anatolia turkey abstract the neogene and quaternary volcanism of central anatolia represents the central sector of the anatolian volcanic arc related to continental collision between the afro arabian and eurasian plates it is closely associated with a complex system of tectonic depressions related to brittle deformations of transtentional type and which commenced in the late miocene the volcanism here considered can be divided into three main periods of activity separated by important deformative and erosive events the first period is represented by a mostly andesitic effusive activity the second period is characterized by the emplacement of a thick ignimbritic sequence and shows an areal distribution up to 11 000 km 2 seven ignimbrite units have been recognized the three main units were found at a distance of more than 100 km from the presumed source area geological and sedimentological data lead us to recognize the melendiz dag volcanic complex and the ciftlik caldera as the probable ignimbrites source vent during the third period great andesitic basaltic stratovolcanoes and a number of prevalently acid monogenic centres developed the relationship between the volcanic activity is clearly conditioned by the main transcurrent fault systems present in central anatolia the neogene quaternary volcanic activity prevalently developed along the ene wsw karaman sivas lineament most of the great central volcanoes developed at the intersection between the ene wsw trends and the ecemis and tuz golu transcurrent faults the structural interpretation of the quaternary monogenic centres is more difficult probably they are related to the very recent n s fault swarms which cross the anatolides and the taurus range