geology and geochemistry of middle eocene maden complex ferromanganese deposits from the elazig malatya region eastern turkey abstract in the study region the puturge precambrian permian metamorphic rocks the upper jurassic lower cretaceous guleman ophiolites the upper cretaceous lower eocene hazar unit the campanian lower maastrichtian aged elazig magmatics and the middle eocene maden complex crop out extensively the maden complex containing ferromanganese mineralization unconformably overlies the puturge metamorphic rocks the guleman ophiolites and the hazar unit and is unconformably overlain by plio quaternary sediments the ferromanganese mn fe ores in the elazig malatya region eastern turkey are hosted in the mudstone member of the volcano sedimentary part of the middle eocene maden complex as lenses or interbedded layers in the elazig malatya region mn fe ores occur at eight localities namely beyhan palu sarikamis kockale germili hazar alihan and kom mn fe ores are found in the kockale and palu deposits as a single bed but in the hazar and kom deposits as two beds and in the sarikamis germili and alihan deposits in three levels the thickness of these mineralized levels ranges from 0 3 m to 10 m all the investigated mineralizations are conformable with the foot wall mudstones braunite bixbyite jacobsite pyrolusite manganite and psilomelane are the main manganese oxide minerals hematite barite and pyrite are also found in variable amounts in the ferromanganese ores the trace element content of all studied ferromanganese deposits is generally in low concentrations and tends to enrichment in the assemblage of ba sr v cu pb zn and as with a geochemical characteristic similar to hydrothermal deposits rare earth element ree patterns of the maden complex mn fe deposits support a hydrothermal origin with a slight enrichment in the middle ree 4 04 29 91 ppm average 16 49 and a slightly high concentration of total ree 92 40 738 23 ppm average 517 85 in all the investigated deposits ree patterns displayed negative ce 0 08 to 0 72 average 0 15 and eu 0 55 to 0 82 average 0 72 anomalies this shows that low temperature hydrothermal fluids played an important role in the formation of mineralization the ore deposition is similar to that of sedimentary exhalative mineralization deposited within the maden marginal basin

long term surface temperature modeling of pluto abstract nasa s new horizons reconnaissance of the pluto system has revealed at high resolution the striking albedo contrasts from polar to equatorial latitudes on pluto as well as the sharpness of boundaries for longitudinal variations these contrasts suggest that pluto must undergo dynamic evolution that drives the redistribution of volatiles using the new horizons results as a template we explore the surface temperature variations driven seasonally on pluto considering multiple timescales these timescales include the current orbit 248 years as well as the timescales for obliquity precession peak to peak amplitude of 23 over 3 million years and regression of the orbital longitude of perihelion 3 7 million years these orbital variations create epochs of extreme seasons where one pole receives a short relatively warm summer and long winter while the other receives a much longer but less intense summer and short winter we use thermal modeling to build upon the long term insolation history model described by earle and binzel 2015 and investigate how these seasons couple with pluto s albedo contrasts to create temperature effects from this study we find that a bright region at the equator once established can become a site for net deposition we see the region informally known as sputnik planitia as an example of this and find it will be able to perpetuate itself as an always available cold trap thus having the potential to survive on million year or substantially longer timescales meanwhile darker low albedo regions near the equator will remain relative warm and generally not attract volatile deposition we argue that the equatorial region is a preservation zone for whatever albedo is seeded there this offers insight as to why the equatorial band of pluto displays the planet s greatest albedo contrasts

albedo matters understanding runaway albedo variations on pluto abstract the data returned from nasa s new horizons reconnaissance of the pluto system show striking albedo variations from polar to equatorial latitudes as well as sharp longitudinal boundaries pluto has a high obliquity currently 119 that varies by 23 over a period of less than 3 million years this variation combined with its regressing longitude of perihelion 360 over 3 7 million years creates epochs of super seasons where one pole is pointed at the sun at perihelion thereby experiencing a short relatively warm summer followed by its longest possible period of winter darkness in contrast the other pole experiences a much longer less intense summer and a short winter season we use a simple volatile sublimation and deposition model to explore the relationship between albedo variations latitude and volatile sublimation and deposition for the current epoch as well as historical epochs during which pluto experienced these super seasons our investigation quantitatively shows that pluto s geometry creates the potential for runaway albedo and volatile variations particularly in the equatorial region which can sustain stark longitudinal contrasts like the ones we see between tombaugh regio and the informally named cthulhu regio

tectonics and magmatism in turkey and the surrounding area this volume contains 23 papers from a range of international contributors describing recent research into the tectonics and magmatism of turkey and its surroundings this region is sited at the collision zone between eurasia and afro arabia and as such provides an extraordinarily complete and well exposed record of the staged tectonic evolution of this sector of the alpine himalayan orogen the geological history of this area involves separation of continental fragments from the margin of gondwana their migration across the tethyan oceans the subsequent closure of these oceans and finally the development of the neotectonic regime which continues to evolve to the present day such a comprehensive record is relevant to the understanding of collisional zones worldwide the volume is divided into five sections tethyan evolution neotethyan ophiolites post tethyan basin evolution neotectonics and igneous activity the first two sections deal with tethyan oceans whose growth and subsequent closure dominated the geodynamic framework in the mesozoic and cenozoic the subsequent sections deal with more recent geological developments from the balkan peninsula in the west to the transcaucasus in the east that followed consumption of the tethyan oceans there is a broad mix of papers throughout the volume wide ranging review papers on ocean development and extensional tectonics are followed by detailed descriptions of petrology and geochemistry and geographically focused studies on basin evolution specific aspects of extensional and strike slip tectonics and discussions of the relationship of magmatic activity to the tectonic development of the area tectonics and magmatism in turkey and the surrounding area presents up to date results and ideas from a large number of international contributors on a wide range of current research activity in this region it is essential reading for all geoscientists with an interest in both academic and applied aspects of eastern mediterranean geology

pluto pits and mantles on uplands north and east of sputnik planitia abstract the highlands region north and east of sputnik planitia can be subdivided into seven terrain types based on their physiographic expression the northern rough uplands are characterized by jagged uplands and broad troughs and it may contain a deeply eroded ancient mantle dissected terrain has been interpreted to have been eroded by paleo glaciation the smooth uplands and pits terrain contains broad rolling uplands surrounding complexes of pits some of which contain smooth floors the uplands are mantled by smooth surfaced deposits possibly derived from adjacent pits through low power explosive cryovolcanism or through slow vapor condensation the eroded smooth uplands appear to have originally been smooth uplands and pits terrain modified by small scale sublimation pitting the bright pitted uplands features intricate texturing by reticulate ridges that may have originated by sublimation erosion volatile condensation or both the bladed terrain is characterized by parallel ridges oriented north south and is discussed in a separate paper the dark uplands are mantled with reddish deposits that may be atmospherically deposited tholins their presence has affected long term landform evolution widespread pit complexes occur on most of the terrain units most appear to be associated with tectonic lineations some pits are floored by broad expanses of ices whereas most feature deep conical depressions a few pit complexes are enclosed by elevated rims of uncertain origin

depositional controls on reservoir properties in a braid delta sandstone tirrawarra oil field south australia the tirrawarra sandstone contains 146 million bbl of oil in tirrawarra field in the cooper basin of south australia we used core well logs and petrophysical data to construct a depositional facies based flow unit model of the reservoir which describes rock properties and hydrocarbon saturations in three dimensions using the model to calculate volumes and residency of original and remaining oil in place we identified an additional 36 million bbl of oil in place and improved understanding of past production patterns the tirrawarra sandstone reservoir was deposited in a carboniferous permian proglacial intracratonic setting and is composed of lacustrine and fluvial facies assemblages the stratigraphic framework of these nonmarine facies is defined by distinctive stacking patterns and erosional unconformities mudstone dominated zones that are analogous to marine maximum flooding surfaces bound the reservoir at its base a progradational lacustrine delta system composed of lenticular mud clast rich sandstones enclosed in mudstone is truncated by an unconformity sandstones in these lower deltaic facies lost most of their porosity by mechanical compaction of ductile grains above the unconformity a braid delta system dominated by aggradational bed load channel fill sandstones forms the core of he reservoir sediment reworking by channel migration and locally by shore zone processes created quartz rich multilateral sandstones which retained the highest porosity and permeability of all the reservoir facies and contained most of the original oil in place the braid delta is erosionally truncated and overlain by a more proximal braid plain system braided channel sandstones however are overlain by lenticular meandering channel sandstones which in turn grade upward into widespread mudstones and coals thus this uppermost part of the reservoir displays a retrogradational stacking pattern and upward decreasing reservoir quality on the basis of the systematic arrangement of facies within this stratigraphic framework as well as facies related differences in composition and texture we identified reservoir flow units that have characteristic petrophysical properties our results demonstrate that depositional variables are the primary controls on reservoir quality and productivity in the tirrawarra sandstone

the berit transect of the tauride thrust belt s turkey late cretaceous early cenozoic accretionary collisional processes related to closure of the southern neotethys abstract we report on an integrated study of a critical segment of the tauride thrust belt in se turkey berit area units related to two sutures are exposed in the northerly and southerly parts of the area studied in the north the upper cretaceous binboga melange reflects the closure of a northerly mesozoic oceanic basin in the south contrasting units document the closure of the southern neotethys in the south the berit or goksun ophiolite formed as an incipient oceanic arc within the southern neotethys during the late cretaceous c 90 ma intercalated amphibolite granulite facies rocks may record a dismembered metamorphic sole an underlying meta sedimentary meta volcanic unit is interpreted as accreted continental rift and oceanic seamount lithologies the berit ophiolite was accreted to the tauride active continental margin to the north around 85 ma and was then intruded by calc alkaline granites c 70 85 ma northerly margin units were exhumed and covered by shelf carbonate sediments during latest cretaceous early cenozoic time northward subduction during the mid cenozoic c 45 ma resulted in back arc extension along the tauride active margin and subduction influenced volcanism possibly controlled by slab roll back during oligocene early miocene time the southern neotethys closed and the tauride active margin was telescoped to create the present south vergent thrust stack this was accompanied by mass wasting of the advancing allochthon to form sub aqueous frontal olistostromes the arabian platform was over ridden by mid miocene time followed by left lateral strike slip along the east anatolian fault zone as anatolia began to escape westwards towards the aegean sea

plate tectonics and the evolution of the british isles this paper is an essay on the rationalism and difficulties of the geological corollaries of plate tectonics with illustrations particularly from the geological history of the british isles there is special emphasis on the mechanics of continental lithosphere in extension when basins are formed and in convergence whereby continental lithosphere thinned in extension is shortened and restacked to form orogenic belts an upper lithosphere stress concentrating elastic lid suffers extremely complex inhomogeneous deformations above a simpler viscoelastic lower lithosphere whose deformation drives strain and displacement in the elastic lid the very nature of plate tectonics as relative motion among a multi plate mosaic of plates provides a rational semi quantitative framework for large scale geological complexity in space and time the caledonian and hercynian history of the british isles may be explained semi quantitatively in terms of plate boundary evolution but it is not possible to define unequivocal solutions the rationalism of plate tectonics is exhibited on a smaller more direct field scale by many of the complexities of ophiolite complexes such as ballantrae scotland that can be explained as the effects of the evolution of ridge ridge transforms and by diachronous deformation and sedimentation in subduction accretion prisms such as the southern uplands deformational and sedimentary patterns in nw europe from triassic times to the present day resulted from a complex interaction of extensional events related to diachronous atlantic opening and compressional events related to sequential alpine shortening phases those widespread events are typical of intracontinental plate boundary systems and create great difficulties for the geologist wishing to decipher relative plate motion from geological sequences because huge areas much larger than the british isles must be analysed and synthesized before much sense can be extracted further difficulties arise from the palinspastic and preservation problems of convergent boundaries orogenic shortening telescopes and partially subducts facies belts most orogenic belts were assembled as a collage of displaced and rotated terrain elements that were subsequently flattened elongated and straightened to an apparent but deceiving simplicity therefore while plate tectonics provides a rational geological framework against which for example british basin evolution can be tested and explained we cannot yet use the geological effects of plate boundary evolution to reconstruct relative plate motion quantitatively

convection in a volatile nitrogen ice rich layer drives pluto s geological vigour the volatile ice filled basin informally named sputnik planum is central to pluto s geological activity this ice layer is organized into cells or polygons and it is now shown that convective overturn in a several kilometre thick layer of solid nitrogen can explain both the presence of the cells and their great width nasa s new horizons spacecraft has revealed fascinating details of the surface of pluto including a vast ice filled basin known as sputnik planum which is central to pluto s geological activity much of the surface of sputnik planum consisting mostly of nitrogen ice is divided into irregular polygons that are tens of kilometres in diameter and whose centres rise tens of metres above their sides two papers in this issue of nature analyse new horizons images of this polygonal terrain both conclude that it is continually being resurfaced by convection but arrive at contrasting models for the process alexander trowbridge et al report a parameterized convection model in which the nitrogen ice is vigorously convecting ten or more kilometres thick and about a million years old william mckinnon et al from the new horizons team show that sluggish lid convective overturn in a several kilometre thick layer of solid nitrogen can explain both the presence of the cells and their great width the vast deep volatile ice filled basin informally named sputnik planum is central to pluto s vigorous geological activity1 2 composed of molecular nitrogen methane and carbon monoxide ices3 but dominated by nitrogen ice this layer is organized into cells or polygons typically about 10 to 40 kilometres across that resemble the surface manifestation of solid state convection1 2 here we report on the basis of available rheological measurements4 that solid layers of nitrogen ice with a thickness in excess of about one kilometre should undergo convection for estimated present day heat flow conditions on pluto more importantly we show numerically that convective overturn in a several kilometre thick layer of solid nitrogen can explain the great lateral width of the cells the temperature dependence of nitrogen ice viscosity implies that the ice layer convects in the so called sluggish lid regime5 a unique convective mode not previously definitively observed in the solar system average surface horizontal velocities of a few centimetres a year imply surface transport or renewal times of about 500 000 years well under the ten million year upper limit crater retention age for sputnik planum2 similar convective surface renewal may also occur on other dwarf planets in the kuiper belt which may help to explain the high albedos shown by some of these bodies

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

the misis andirin complex a mid tertiary melange related to late stage subduction of the southern neotethys in s turkey abstract the mid tertiary mid eocene to earliest miocene misis andirin complex documents tectonic sedimentary processes affecting the northerly active margin of the south tethys neotethys in the easternmost mediterranean region each of three orogenic segments misis in the sw andirin central and engizek in the ne represent parts of an originally continuous active continental margin a structurally lower volcanic sedimentary unit includes late cretaceous arc related extrusives and their lower tertiary pelagic cover this unit is interpreted as an early tertiary remnant of the mesozoic south tethys the overlying melange unit is dominated by tectonically brecciated blocks 100 m across of mesozoic neritic limestone that were derived from the tauride carbonate platform to the north together with accreted ophiolitic material the melange matrix comprises polymict debris flows high to low density turbidites and minor hemipelagic sediments the misis andirin complex is interpreted as an accretionary prism related to the latest stages of northward subduction of the south tethys and diachronous continental collision of the tauride eurasian and arabian african plates during mid eocene to earliest miocene time slivers of upper cretaceous oceanic crust and its early tertiary pelagic cover were accreted while blocks of mesozoic platform carbonates slid from the overriding plate tectonic mixing and sedimentary recycling took place within a trench subduction culminated in large scale collapse of the overriding northern margin and foundering of vast blocks of neritic carbonate into the trench a possible cause was rapid roll back of dense downgoing mesozoic oceanic crust such that the accretionary wedge taper was extended leading to gravity collapse melange formation was terminated by underthrusting of the arabian plate from the south during earliest miocene time collision was diachronous in the east engizek range and se anatolia collision generated a lower miocene flexural basin infilled with turbidites and a flexural bulge to the south miocene turbiditic sediments also covered the former accretionary prism further west misis range the easternmost mediterranean remained in a pre collisional setting with northward underthrusting incipient subduction along the cyprus arc the lower miocene basins to the north misis and adana indicate an extensional to transtensional setting the ne sw linking segment andirin probably originated as a mesozoic palaeogeographic offset of the tauride margin this was reactivated by strike slip and transtension during later tertiary diachronous collision related to on going plate convergence the former accretionary wedge upper plate was thrust over the lower miocene turbiditic basins in mid late miocene time the plio quaternary was dominated by left lateral strike slip along the east anatolian transform fault and also along fault strands cutting the misis andirin complex

oceanic crust generation in an island arc tectonic setting se anatolian orogenic belt turkey a number of late cretaceous ophiolitic bodies are located between the metamorphic massifs of the southeast anatolian orogenic system one of them the goksun ophiolite northern kahramanmaras which crops out in a tectonic window bounded by the malatya metamorphic units on both the north and south is located in the ew trending nappe zone of the southeast anatolian orogenic belt between goksunand afsin northern kahramanmaras it consists of ultramafic mafic cumulates isotropic gabbro a sheeted dyke complex plagiogranite volcanic rocks and associated volcanosedimentary units the ophiolitic rocks and the tectonically overlying malatya keban metamorphic units were intruded by syn collisional granitoids 85 ma the volcanic units are characterized by a wide spectrum of rocks ranging in composition from basalt to rhyolite the sheeted dykes consist of diabase and microdiorite whereas the isotropic gabbros consist of gabbro diorite and quartzdiorite the magmatic rocks in the goksunophiolite are part of a co magmatic differentiated series of subalkaline tholeiites selective enrichment of some lil elements rb ba k sr and th and depletion of the hfs elements nb ta ti zr relative to n morb are the main features of the upper crustal rocks the presence of negative anomalies for ta nb ti the ratios of selected trace elements nb th th yb ta yb and normalized ree patterns all are indicative of a subduction related environment all the geochemical evidence both from the volcanic rocks and the deeper levels sheeted dykes and isotropic gabbro show that the goksun ophiolite formed during the mature stage of a suprasubduction zone ssz tectonic setting in the southern branch of the neotethyan ocean between the malatya keban platform to the north and the arabian platform to the south during late cretaceous times geological geochronological and petrological data on the goksun ophiolite and the baskil magmatic arc suggest that there were two subduction zones the first one dipping beneath the malatya keban platform generating the baskil magmatic arc and the second one further south within the ocean basin generating the goksun ophiolite in a suprasubduction zone environment

geodynamic significance of granitoid magmatism in the southeast anatolian orogen geochemical and geochronogical evidence from goksun afsin kahramanmaras turkey region in southeast anatolia there are number of tectonomagmatic units in the kahramanmaras malatya elazig region that are important in understanding the geological evolution of the southeast anatolian orogenic belt during the late cretaceous these are a metamorphic massifs b ophiolites c ophiolite related metamorphics and d granitoids the granitoids i e goksun afsin in kahramanmaras dogansehir in malatya and baskil in elazig intrude all the former units in a ne sw trending direction the granitoid in goksun afsin kahramanmaras region is mainly composed of granodioritic and granitic in composition the granodiorite contains a number of amphibole bearing mafic microgranular enclaves of different sizes whereas the granite is intruded by numerous aplitic dikes the granitoid rocks have typical calcalkaline geochemical features the ree and ocean ridge granite normalized multi element patterns and tectonomagmatic discrimination diagrams as well as biotite geochemistry suggest that the granitoids were formed in a volcanic arc setting the k ar geochronology of the granitoid rocks yielded ages ranging from 85 76 3 17 to 77 49 1 91 ma the field geochemical and geochronological data suggest the following late cretaceous tectonomagmatic scenario for southeast anatolia the ophiolites were formed in a suprasubduction zone tectonic setting whereas the ophiolite related metamorphic rocks formed either during the initiation of intraoceanic subduction or late thrusting 90 ma these units were then overthrust by the malatya keban platform during the progressive elimination of the southern neotethys thrusting of the malatya keban platform over the ophiolites and related metamorphic rocks was followed by the intrusion of the granitoids 88 85 ma along the tauride active continental margin in the southern neotethys

bladed terrain on pluto possible origins and evolution abstract bladed terrain on pluto consists of deposits of massive ch 4 which are observed to occur within latitudes 30 of the equator and are found almost exclusively at the highest elevations 2 km above the mean radius our analysis indicates that these deposits of ch 4 preferentially precipitate at low latitudes where net annual solar energy input is lowest ch 4 and n 2 will both precipitate at low elevations however since there is much more n 2 in the atmosphere than ch 4 the n 2 ice will dominate at these low elevations at high elevations the atmosphere is too warm for n 2 to precipitate so only ch 4 can do so we conclude that following the time of massive ch 4 emplacement there have been sufficient excursions in pluto s climate to partially erode these deposits via sublimation into the blades we see today blades composed of massive ch 4 ice implies that the mechanical behavior of ch 4 can support at least several hundred meters of relief at pluto surface conditions bladed terrain deposits may be widespread in the low latitudes of the poorly seen sub charon hemisphere based on spectral observations if these locations are indeed bladed terrain deposits they may mark heretofore unrecognized regions of high elevation

the ch4 cycles on pluto over seasonal and astronomical timescales abstract pluto s surface is covered in numerous ch4 ice deposits that vary in texture and brightness as revealed by the new horizons spacecraft as it flew by pluto in july 2015 these observations suggest that ch4 on pluto has a complex history involving reservoirs of different composition thickness and stability controlled by volatile processes occurring on different timescales in order to interpret these observations we use a pluto volatile transport model able to simulate the cycles of n2 and ch4 ices over millions of years by assuming fixed solid mixing ratios we explore how changes in surface albedos emissivities and thermal inertias impact volatile transport this work is therefore a direct and natural continuation of the work by bertrand et al 2018 which only explored the n2 cycles results show that bright ch4 deposits can create cold traps for n2 ice outside sputnik planitia leading to a strong coupling between the n2 and ch4 cycles depending on the assumed albedo for ch4 ice the model predicts ch4 ice accumulation 1 at the same equatorial latitudes where the bladed terrain deposits are observed supporting the idea that these ch4 rich deposits are massive and perennial or 2 at mid latitudes 25 70 forming a thick mantle which is consistent with new horizons observations in our simulations both ch4 ice reservoirs are not in an equilibrium state and either one can dominate the other over long timescales depending on the assumptions made for the ch4 albedo this suggests that long term volatile transport exists between the observed reservoirs the model also reproduces the formation of n2 deposits at mid latitudes and in the equatorial depressions surrounding the bladed terrain deposits as observed by new horizons at the poles only seasonal ch4 and n2 deposits are obtained in pluto s current orbital configuration finally we show that pluto s atmosphere always contained over the last astronomical cycles enough gaseous ch4 to absorb most of the incoming lyman flux

a search for temporal changes on pluto and charon abstract a search for temporal changes on pluto and charon was motivated by 1 the discovery of young surfaces in the pluto system that imply ongoing or recent geologic activity 2 the detection of active plumes on triton during the voyager 2 flyby and 3 the abundant and detailed information that observing geologic processes in action provides about the processes a thorough search for temporal changes using new horizons images was completed images that covered the same region were blinked and manually inspected for any differences in appearance the search included full disk images such that all illuminated regions of both bodies were investigated and higher resolution images such that parts of the encounter hemispheres were investigated at finer spatial scales changes of appearance between different images were observed but in all cases were attributed to variability of the imaging parameters especially geometry or artifacts no differences of appearance that are strongly indicative of a temporal change were found on the surface or in the atmosphere of either pluto or charon limits on temporal changes as a function of spatial scale and temporal interval during the new horizons encounter are determined the longest time interval constraint is one pluto charon rotation period 6 4 earth days contrast reversal and high phase bright features that change in appearance with solar phase angle are identified the change of appearance of these features is most likely due to the change in phase angle rather than a temporal change had active plumes analogous to the plumes discovered on triton been present on the encounter hemispheres of either pluto or charon they would have been detected the absence of active plumes may be due to temporal variability i e plumes do occur but none were active on the encounter hemispheres during the epoch of the new horizons encounter or because plumes do not occur several dark streak features that may be deposits from past plumes are identified

sublimation waves geomorphic markers of interactions between icy planetary surfaces and winds abstract sublimation waves are periodic linear and transverse bedforms that grow by sublimation of icy substrates under turbulent winds they occur in different environments of the earth and other planets where the climate is favorable to sublimation their morphological and kinematic characteristics wavelength migration velocity characteristic time of formation depend on the environmental conditions in which they develop atmosphere viscosity wind speed sublimation rate to highlight these relations we designed a theoretical model for their formation based on models previously designed for dissolution bedforms from a linear stability analysis of the model we derived a dispersion relation and three scaling laws these are validated by comparison with measurements available for two natural terrestrial examples blue ice areas of the antarctic ice sheets and ice caves and with new measurements in a laboratory experiment they are applied to linear bedforms of hitherto unknown origin that we identified on the martian north polar cap we thus demonstrate that sublimation waves are convenient geomorphic markers to constrain surface compositions atmospheric properties climates and winds on terrestrial ice sheets and other icy planetary surfaces

pluto s global surface composition through pixel by pixel hapke modeling of new horizons ralph leisa data abstract on july 14th 2015 nasa s new horizons mission gave us an unprecedented detailed view of the pluto system the complex compositional diversity of pluto s encounter hemisphere was revealed by the ralph leisa infrared spectrometer on board of new horizons we present compositional maps of pluto defining the spatial distribution of the abundance and textural properties of the volatiles methane and nitrogen ices and non volatiles water ice and tholin these results are obtained by applying a pixel by pixel hapke radiative transfer model to the leisa scans our analysis focuses mainly on the large scale latitudinal variations of methane and nitrogen ices and aims at setting observational constraints to volatile transport models specifically we find three latitudinal bands the first enriched in methane extends from the pole to 55 n the second dominated by nitrogen continues south to 35 n and the third composed again mainly of methane reaches 20 n we demonstrate that the distribution of volatiles across these surface units can be explained by differences in insolation over the past few decades the latitudinal pattern is broken by sputnik planitia a large reservoir of volatiles with nitrogen playing the most important role the physical properties of methane and nitrogen in this region are suggestive of the presence of a cold trap or possible volatile stratification furthermore our modeling results point to a possible sublimation transport of nitrogen from the northwest edge of sputnik planitia toward the south

late cretaceous cenozoic subduction collision history of the southern neotethys new evidence from the caglayancerit area se turkey evidence of the subduction collision history of the s neotethys is well exposed in the frontal part of the se anatolian thrust belt and the adjacent arabian continental margin the foreland succession in the study area begins with eocene shelf carbonates ranging from shallow marine to deeper marine without sedimentary input from the tauride continent to the north after a regional hiatus oligocene sedimentation resumed during the early miocene with terrigenous gravity flow deposition in the north lice formation and shallow marine carbonates further south clastic detritus was derived from the tauride continent and oceanic accretionary material the base of the overriding tauride allochthon comprises ophiolite derived debris flows ophiolite related melange and dismembered ophiolitic rocks above this the regional scale bulgurkaya sedimentary melange an olistostrome includes blocks and dismembered thrust sheets of metamorphic rocks limestone and sandstone which include late cretaceous and eocene foraminifera the matrix is mainly strongly deformed eocene oligocene mudrocks hemipelagic marl and sandstone turbidites the thrust stack is topped by a regionally extensive thrust sheet malatya metamorphic unit which includes greenschist facies marble calcschist schist and phyllite representing tauride continental crust beginning during the late mesozoic the s neotethys subducted northwards beneath a backstop represented by the tauride microcontinent malatya metamorphic unit ophiolites formed within the s neotethys and accreted to the tauride active margin large scale sedimentary melange developed along the tauride active margin during eocene oligocene on the arabian margin a sedimentary hiatus and tilting oligocene is interpreted to record initial continental collision the early miocene terrigenous gravity flows represent a collision related flexural foreland basin southward overthrusting of the tauride allochthon took place during early middle miocene associated regional uplift triggered large scale alluvial deposition the foreland folded and faulted in response to suture zone tightening late miocene left lateral strike slip characterised the plio pleistocene

vigorous convection as the explanation for pluto s polygonal terrain a parameterized convection model and observations of the puzzling polygons of the sputnik planum region of pluto are used to compute the rayleigh number of its nitrogen ice and show that it is vigorously convecting kilometres thick and about a million years old nasa s new horizons spacecraft has revealed fascinating details of the surface of pluto including a vast ice filled basin known as sputnik planum which is central to pluto s geological activity much of the surface of sputnik planum consisting mostly of nitrogen ice is divided into irregular polygons that are tens of kilometres in diameter and whose centres rise tens of metres above their sides two papers in this issue of nature analyse new horizons images of this polygonal terrain both conclude that it is continually being resurfaced by convection but arrive at contrasting models for the process alexander trowbridge et al report a parameterized convection model in which the nitrogen ice is vigorously convecting ten or more kilometres thick and about a million years old william mckinnon et al from the new horizons team show that sluggish lid convective overturn in a several kilometre thick layer of solid nitrogen can explain both the presence of the cells and their great width pluto s surface is surprisingly young and geologically active1 one of its youngest terrains is the near equatorial region informally named sputnik planum which is a topographic basin filled by nitrogen n2 ice mixed with minor amounts of ch4 and co ices1 nearly the entire surface of the region is divided into irregular polygons about 20 30 kilometres in diameter whose centres rise tens of metres above their sides the edges of this region exhibit bulk flow features without polygons1 both thermal contraction and convection have been proposed to explain this terrain1 but polygons formed from thermal contraction analogous to ice wedges or mud crack networks 2 3 of n2 are inconsistent with the observations on pluto of non brittle deformation within the n2 ice sheet here we report a parameterized convection model to compute the rayleigh number of the n2 ice and show that it is vigorously convecting making rayleigh benard convection the most likely explanation for these polygons the diameter of sputnik planum s polygons and the dimensions of the floating mountains the hills of of water ice along the edges of the polygons suggest that its n2 ice is about ten kilometres thick the estimated convection velocity of 1 5 centimetres a year indicates a surface age of only around a million years

methane distribution on pluto as mapped by the new horizons ralph mvic instrument abstract the data returned from nasa s new horizons spacecraft have given us an unprecedented detailed look at the pluto system new horizons ralph mvic multispectral visible imaging camera is composed of 7 independent ccd arrays on a single substrate among these are a red channel 540 700 nm near infrared channel 780 975 nm and narrow band methane channel 860 910 nm by comparing the relative reflectance of these channels we are able to produce high resolution methane equivalent width based on the 890 nm absorption band and spectral slope maps of pluto s surface from these maps we can then quantitatively study the relationships between methane distribution redness and other parameters like latitude and elevation we find pluto s surface to show a great diversity of terrains particularly in the equatorial region between 30 n and 30 s latitude methane equivalent width also shows some dependence on elevation while spectral slope shows very little

geodynamics seismicity and seismic hazards of the caucasus abstract being a part of ongoing continental collision between the arabian and eurasian plates the caucasus region is a remarkable site of moderate to strong seismicity where devastating earthquakes caused significant losses of lives and livelihood in this article we survey geology and geodynamics of the caucasus and its surroundings magmatism and heat flow active tectonics and tectonic stresses caused by the collision and shortening gravity and density models and overview recent geodetic studies related to regional movements the tectonic development of the caucasus region in the mesozoic cenozoic times as well as the underlying dynamics controlling its development are complicated processes it is clear that the collision is responsible for a topographic uplift inversion and for the formation of the fold and thrust belts of the greater and lesser caucasus tectonic deformations in the region is influenced by the wedge shaped rigid arabian block indenting into the relatively mobile region and producing near n s compressional stress and seismicity in the caucasus regional seismicity is analysed with an attention to sub crustal seismicity under the northern foothills of the greater caucasus which origin is unclear whether the seismicity associated with a descending oceanic crust or thinned continental crust recent seismic tomography studies are in favour of the detachment of a lithospheric root beneath the lesser and greater caucasus the knowledge of geodynamics seismicity and stress regime in the caucasus region assists in an assessment of seismic hazard and risk we look finally at existing gaps in the current knowledge and identify the problems which may improve our understanding of the regional evolution active tectonics geodynamics shallow and deeper seismicity and surface manifestations of the lithosphere dynamics among the gaps are those related to uncertainties in regional geodynamic and tectonic evolution e g continental collision and associated shortening and exhumation lithosphere structure deformation and strain stress partitioning and to the lack of comprehensive datasets e g regional seismic catalogues seismic gravity and geodetic surveys

origin and emplacement of the late cretaceous baer bassit ophiolite and its metamorphic sole in nw syria abstract the baer bassit ophiolite of inferred late cretaceous age was emplaced from the south tethys ocean onto the leading edge of the arabian continental margin in latest cretaceous maastrichtian time dismembered sequences in different thrust sheets can be correlated to produce a complete ophiolite sequence with a metamorphic sole at the base overlain in turn by upper mantle tectonite rare cumulates massive and layered gabbros localized high level plagiogranites sheeted dykes basic extrusives and minor fe mn sediments umbers the restored ophiolite sequence is similar to that of the more intact troodos and hatay ophiolites but dissimilar to oman the baer bassit extrusives are magnesian and strongly depleted comparable to primitive island arc tholeiites and some boninitic lavas which favours a subduction related origin a well developed metamorphic sole is divisible into high grade amphibolite facies assemblages in the north and lower grade greenschist facies assemblages in the centre of the region but no complete inverted metamorphic gradient is preserved in any one local area the protoliths of both the high grade amphibolites and lower grade rocks greenschists are interpreted as alkali basalts and pelagic sediments including chert similar to the volcanic rocks in an underlying unmetamorphosed melange the metamorphic fabrics progressively evolved from ductile to brittle during tectonic transport towards the southeast most of the metamorphic fabrics evolved during intense shearing but some of the alkaline metabasites apparently were metamorphosed under relatively static strain conditions the apparent absence of preserved inverted metamorphic gradients in baer bassit may reflect a complex deformation history during emplacement alternatively differing p t conditions may be recorded at different depths at the base of the over riding mantle wedge during emplacement the front of the ophiolite was tectonically imbricated and overthrust by the main ultramafic slab bassit massif the thickest massif baer is underlain by a high grade metamorphic sole and was internally shortened but without thrust duplication of the entire ophiolite sequence following covering by late maastrichtian palaeogene marine calcareous sediments the area was subjected to mid tertiary regional folding this was followed by neogene dominantly left lateral strike slip deformation along the african eurasian plate boundary extending from south of cyprus to the dead sea transform fault as a result the originally emplaced thrust sheets were dissected into three main composite units baer bassit and the southeastern units separated by strongly faulted and sheared ophiolitic blocks and unmetamorphosed volcanic sedimentary melange

physical state and distribution of materials at the surface of pluto from new horizons leisa imaging spectrometer abstract from earth based observations pluto is known to be the host of n2 ch4 and co ices and also a dark red material very limited spatial distribution information is available from rotational visible and near infrared spectral curves obtained from hemispheric measurements in july 2015 the new horizons spacecraft reached pluto and its satellite system and recorded a large set of data the leisa spectro imager of the ralph instruments are dedicated to the study of the composition and physical state of the materials composing the surface in this paper we report a study of the distribution and physical state of the ices and non ice materials on pluto s illuminated surface and their mode and degree of mixing principal component analysis as well as various specific spectral indicators and correlation plots are used on the first set of 2 high resolution spectro images from the leisa instrument covering the whole illuminated face of pluto at the time of the new horizons encounter qualitative distribution maps have been obtained for the 4 main condensed molecules n2 ch4 co h2o as well as for the visible dark red material based on specific spectral indicators using either the strength or the position of absorption bands these 4 molecules are found to indicate the presence of 3 different types of ices n2 rich ch4 co ices ch4 rich co n2 ices and h2o ice the mixing lines between these ices and with the dark red material are studied using scatter plots between the various spectral indicators ch4 is mixed at the molecular level with n2 most probably also with co thus forming a ternary molecular mixture that follows its phase diagram with low solubility limits the occurrence of a n2 rich ch4 rich ices mixing line associated with a progressive decrease of the co ch4 ratio tells us that a fractionation sublimation sequence transforms one type of ice to the other forming either a n2 rich ch4 rich binary mixture at the surface or an upper ch4 rich ice crust that may hide the n2 rich ice below the strong ch4 rich h2o mixing line witnesses the subsequent sublimation of the ch4 rich ice lag left behind by the n2 co sublimation n spring summer or a direct condensation of ch4 ice on the cold h2o ice s autumn the weak mixing line between ch4 containing ices and the dark red material and the very sharp spatial transitions between these ices and this non volatile material are probably due to thermal incompatibility finally the occurrence of a h2o ice red material mixing line advocates for a spatial mixing of the red material covering h2o ice with possibly a small amount intimately mixed in water ice from this analysis of the different materials distribution and their relative mixing lines h2o ice appears to be the substratum on which other ices condense or non volatile organic material is deposited from the atmosphere n2 rich ices seem to evolve to ch4 dominated ices possibly still containing traces of co and n2 as n2 and co sublimate away the spatial distribution of these materials is very complex the high spatial definition of all these composition maps as well as those at even higher resolution that will be soon available will allow us to compare them with pluto s geologic features observed by lorri panchromatic and mvic multispectral imagers to better understand the geophysical processes in action at the surface of this astonishingly active frozen world

basins fractures and volcanoes global cartography and topography of pluto from new horizons abstract the 2015 new horizons flyby has produced the first high resolution maps of morphology and topography of pluto and charon the most distant objects so mapped global integrated mosaics of pluto were produced using both lorri framing camera and mvic line scan camera data showing the best resolution data obtained for all areas of the illuminated surface 78 of the body a unique feature of the pluto imaging data set is the observation of terrains illuminated only by light scattered from atmospheric haze allowing us to map terrains in the southern hemisphere that would otherwise have been in darkness mvic 4 color data were combined with the panchromatic map to produce full color global maps digital elevation models dems over 42 of pluto were produced using combinations of mvic hemispheric scans and lorri mosaics from which slopes at scales of 1 km can be determined pluto can be divided into regions each with distinct topographic signatures corresponding with major physiographic terrain types large areas of pluto are comprised of low relief moderately cratered plains units deeply pitted and glaciated plains east of sputnik planitia are elevated 0 7 km the most dominant topographic feature on pluto is the 1200 by 2000 km wide depression enclosing the bright sputnik planitia ice sheet the surface of which is 2 5 to 3 5 km deep relative to the rim and 2 km deep relative to the mean radius the partial ring of steep sided massifs several of which are more than 5 km high along the western margins of sputnik planitia produce some of the locally highest and steepest relief on pluto with slopes of 40 50 the second major topographic feature is a complex eroded ridge trough system 300 400 km wide and at least 3200 km long extending north to south along the 155 meridian this enormous structure has several kilometers of relief it may predate the large impact event forming the basin though some post sputnik planitia deformation is evident the large depressed partially walled plain hyecho palus lies due southwest of sputnik planitia near the center of hyecho palus lie the circular constructional edifices wright and piccard montes wright mons rises 4 5 km above these plains with a central depression 4 5 km deep whereas piccard mons best observed in haze light rises 5 5 km above the plains but has a bowl shaped central depression 5 5 km below the plains for a total relief of up to 11 km the greatest observed on pluto both of these features are interpreted as constructional volcanic in nature additional prominent topographic features include a 2 3 km high and 600 km wide dome centered on the illuminated iau pole and the amoeboidal plateaus of bladed terrains in the equatorial region which rise 2 5 km above local terrains and are the highest standing geologic units on the encounter hemisphere the mean elevations in the integrated dem for the two radio occultation areas are consistent with the 5 6 km difference in elevation as determined independently by the radio experiment and a limb profile near the egress point confirms the presence of elevated bladed terrains in that area local relief of 3 5 km at massifs troughs and pits supports conclusions that the icy shell of pluto is relatively rigid numerous examples of topographic control of ice or frost deposition occur across pluto including the distinct coloration of the polar dome the elevated terrains of eastern tombaugh regio and along the ridge trough system where ridge tops and fossae rims are covered in different ices than at lower elevations the topographic hypsogram of pluto s encounter hemisphere is strongly bimodal due to the large sputnik planitia depression otherwise the topographic signature of pluto is controlled by deviations from the otherwise dominant low plains including elevated bladed terrain plateaus and the depressed volcanic province including wright and piccard montes

new evidence and model on the evolution of the southeast anatolian orogen this paper describes the orogenic evolution of the southeast anatolian orogenic belt based mostly on new geologic data collected from its constituent tectonic units in the course of new mapping programs of the past decade the southeast anatolian orogenic segment of the alpides may be divided into three approximately east west trending zones from south to north they are the arabian platform followed by a zone of imbrication and then a zone of nappes the arabian platform includes a mostly marine sedimentary succession deposited from early cambrian to middle miocene time the zone of imbrication is a narrow belt sandwiched between the arabian platform and the zone of nappes it consists of imbricated thrust slices emplaced onto a late cretaceous to early miocene sequence the zone of nappes is the highest tectonic unit consisting of two stacks of nappes simply designated the lower and upper nappes the lower nappe is represented by the slices of a polyphase metamorpbic ophiolitic assemblage and the maden group the upper nappe rests on the lower nappe and is represented by the bitlis and poturge metamorphic massifs southeastern anatolia underwent two major episodes of alpide deformation the first occurred during the late cretaceous period when ophiolite was emplaced on the arabian platform this event was not the consequence of a continental collision the ophiolite obduction onto the arabian platform was followed by a regionwide extension and a new marine transgression over the platform immediately after the ophiolite obduction the second episode of deformation occurred during middle eocene miocene time in two distinct stages as a result of the progressive elimination and complete closure of the ocean s which led to the collision between the zone of nappes located to the north being a part of eurasia and the arabian plate the maden marginal basin formed north of the subduction zone that eliminated the ocean between eurasia and arabia along the southern margin of the taurus belt and abutted the arabian plate much later during the final collision the second episode of deformation formed the present orogenic segment leading to the amalgamation of different tectonic units these amalgamated nappes collided with the arabian plate and welded onto it at the latest stage of the orogenic evolution during the miocene epoch

modeling cryogenic mud volcanism on pluto abstract subsurface ice cryofluids and ice interactions with ammonia for cryovolcanic materials give the potential ingredients for the formation of mud volcanoes on pluto in order to constrain the possible morphology from images acquired by the new horizons spacecraft we have modeled the formation of mud volcanoes isostatic layers of ice overlain by denser material from a series of possible solid liquid mud compositions methane and ammonia as well as accounting for the full range of eruption variables e g mud viscosity conduit diameter and eruption duration we categorize them into nine specific scenarios based on the composition of the top ice layer and mud composition from these scenarios the maximum height of the potential mud volcano can be calculated we find that ammonia mud sources produce smaller edifice heights and wider flow profiles compared to methane dominant mud cryovolcanoes assuming certain preliminary parameters we also propose the evolution and development of the edifice of wright mons in as little as 3 8 million years given a 10 wt ammonia subsurface mud composition if characterized on pluto s surface mud volcanoes would provide an interesting insight on the subsurface dynamics of solids and cryofluids on pluto

the geology of pluto and charon through the eyes of new horizons nasa s new horizons spacecraft has revealed the complex geology of pluto and charon pluto s encounter hemisphere shows ongoing surface geological activity centered on a vast basin containing a thick layer of volatile ices that appears to be involved in convection and advection with a crater retention age no greater than 10 million years surrounding terrains show active glacial flow apparent transport and rotation of large buoyant water ice crustal blocks and pitting the latter likely caused by sublimation erosion and or collapse more enigmatic features include tall mounds with central depressions that are conceivably cryovolcanic and ridges with complex bladed textures pluto also has ancient cratered terrains up to 4 billion years old that are extensionally faulted and extensively mantled and perhaps eroded by glacial or other processes charon does not appear to be currently active but experienced major extensional tectonism and resurfacing probably cryovolcanic nearly 4 billion years ago impact crater populations on pluto and charon are not consistent with the steepest impactor size frequency distributions proposed for the kuiper belt

neotethyan intraoceanic microplate rotation and variations in spreading axis orientation palaeomagnetic evidence from the hatay ophiolite southern turkey abstract insights into tectonic processes operating in ancient ocean basins are provided by analyses of fragments of oceanic lithosphere preserved as ophiolites during collisional orogenesis here we present a palaeomagnetic analysis of the upper cretaceous hatay kizil dag ophiolite of turkey that provides evidence for intraoceanic microplate rotation and variations in ridge axis orientation in a neotethyan ocean basin magnetizations at 46 sites are shown to be pre deformational in origin and rotated from the relevant reference direction a net tectonic rotation approach to the analysis of the data provides information on permissible net rotation poles and angles and allows uncertainties in input vectors to be considered results demonstrate that all levels of the ophiolite have been rotated anticlockwise by angles in excess of 90 around steeply inclined axes the hatay ophiolite formed in the same supra subduction zone spreading system as the troodos ophiolite cyprus which is known to have rotated 90 anticlockwise in an intraoceanic setting in the late cretaceous to early eocene by considering our results in the context of the known timing of the troodos rotation we infer that 50 60 of rotation of the hatay ophiolite took place as part of an areally extensive troodos microplate this phase of rotation was triggered by initial impingement of the arabian continental margin with the neotethyan subduction trench consistent with models for modern day oceanic microplate rotation in complex convergent plate boundaries the hatay ophiolite then became detached from the actively rotating microplate and was emplaced onto the arabian margin in the maastrichtian undergoing a further 30 40 of anticlockwise rotation during thrusting back stripping of rotations allows correction of the hatay sheeted dykes to their initial orientations the restored dyke trend of 020 differs from that inferred previously for the troodos sheeted dyke complex demonstrating a primary variation in orientation of neotethyan spreading axes such variability is commonly observed in modern spreading systems in marginal basins these may act as analogues for the supra subduction zone spreading inferred for many ophiolites

equilibrium profile development in graded deep water slopes eocene eastern turkey recently published models for deep marine slopes provide a framework for understanding the sedimentary architecture and geometries of major correlative surfaces in this environment these models use concepts which include i the development of erosional and unconformable onlapping relationships in a slope to basin setting by processes other than changes in relative sea level e g earthquake induced gravity flows ii the definition of genetic facies associations and iii the development of base of slope systems by repeated mass wasting in order to establish an equilibrium slope profile these models are based primarily on seismic data from present day slopes or numerical simulation and have not been tested in the field an example from turkey of a progradational eocene basin to slope transition is presented to test these models we found that most mass wasting occurs at the top and not base of the slope that this is likely to be earthquake induced rather than related to changes in relative sea level and that seafloor topography continues to control sand transportation pathways and mass wasting throughout slope apron deposition

observed glacier and volatile distribution on pluto from atmosphere topography processes simulations of the levels of nitrogen methane and carbon monoxide over thousands of years confirm the existence of a nitrogen glacier in sputnik planitia pluto s deepest basin tanguy bertrand and francois forget have developed a model for volatile transport on pluto and use it to simulate the evolution of n2 ch4 and co on the dwarf plant over tens of thousands of earth years the model predicts n2 ice accumulation in the deepest low latitude basin and the threefold increase in atmospheric pressure that has been observed to occur since 1988 this points to atmospheric topographic processes as the origin of the prominent equatorial n2 glacier known as sputnik planitia formerly sputnik planum this is one of four papers on the geology of sputnik planitia in this issue of nature in news views amy barr puts these latest contributions into context pluto has a variety of surface frosts and landforms as well as a complex atmosphere1 there is ongoing geological activity related to the massive sputnik planitia glacier mostly made of nitrogen n2 ice mixed with solid carbon monoxide and methane2 covering the 4 kilometre deep 1 000 kilometre wide basin of sputnik planitia1 3 near the anti charon point the glacier has been suggested to arise from a source region connected to the deep interior or from a sink collecting the volatiles released planetwide1 thin deposits of n2 frost however were also detected at mid northern latitudes and methane ice was observed to cover most of pluto except for the darker frost free equatorial regions2 here we report numerical simulations of the evolution of n2 methane and carbon monoxide on pluto over thousands of years the model predicts n2 ice accumulation in the deepest low latitude basin and the threefold increase in atmospheric pressure that has been observed to occur since 19884 5 6 this points to atmospheric topographic processes as the origin of sputnik planitia s n2 glacier the same simulations also reproduce the observed quantities of volatiles in the atmosphere and show frosts of methane and sometimes n2 that seasonally cover the mid and high latitudes explaining the bright northern polar cap reported in the 1990s7 8 and the observed ice distribution in 20152 the model also predicts that most of these seasonal frosts should disappear in the next decade

global cenozoic paleobathymetry with a focus on the northern hemisphere oceanic gateways abstract the evolution of the northern hemisphere oceanic gateways has facilitated ocean circulation changes and may have influenced climatic variations in the cenozoic time 66 ma 0 ma however the timing of these oceanic gateway events is poorly constrained and is often neglected in global paleobathymetric reconstructions we have therefore re evaluated the evolution of the northern hemisphere oceanic gateways i e the fram strait greenland scotland ridge the central american seaway and the tethys seaway and embedded their tectonic histories in a new global paleobathymetry and topography model for the cenozoic time our new paleobathymetry model incorporates northeast atlantic paleobathymetric variations due to iceland mantle plume activity updated regional plate kinematics and models for the oceanic lithospheric age sediment thickness and reconstructed oceanic plateaus and microcontinents we also provide a global paleotopography model based on new and previously published regional models in particular the new model documents important bathymetric changes in the northeast atlantic and in the tethys seaway at eocene oligocene transition 34 ma the time of the first glaciations of antarctica believed to be triggered by the opening of the southern ocean gateways i e the drake passage and the tasman gateway and subsequent antarctic circumpolar current initiation our new model can be used to test whether the northern hemisphere gateways could have also played an important role modulating ocean circulation and climate at that time in addition we provide a set of realistic global bathymetric and topographic reconstructions for the cenozoic time at one million year interval for further use in paleo ocean circulation and climate models

the nitrogen cycles on pluto over seasonal and astronomical timescales abstract pluto s landscape is shaped by the endless condensation and sublimation cycles of the volatile ices covering its surface in particular the sputnik planitia ice sheet which is thought to be the main reservoir of nitrogen ice displays a large diversity of terrains with bright and dark plains small pits and troughs topographic depressions and evidences of recent and past glacial flows outside sputnik planitia new horizons also revealed numerous nitrogen ice deposits in the eastern side of tombaugh regio and at mid northern latitudes these observations suggest a complex history involving volatile and glacial processes occurring on different timescales we present numerical simulations of volatile transport on pluto performed with a model designed to simulate the nitrogen cycle over millions of years taking into account the changes of obliquity solar longitude of perihelion and eccentricity as experienced by pluto using this model we first explore how the volatile and glacial activity of nitrogen within sputnik planitia has been impacted by the diurnal seasonal and astronomical cycles of pluto results show that the obliquity dominates the n2 cycle and that over one obliquity cycle the latitudes of sputnik planitia between 25 s 30 n are dominated by n2 condensation while the northern regions between 30 n and 50 n are dominated by n2 sublimation we find that a net amount of 1 km of ice has sublimed at the northern edge of sputnik planitia during the last 2 millions of years it must have been compensated by a viscous flow of the thick ice sheet by comparing these results with the observed geology of sputnik planitia we can relate the formation of the small pits and the brightness of the ice at the center of sputnik planitia to the sublimation and condensation of ice occurring at the annual timescale while the glacial flows at its eastern edge and the erosion of the water ice mountains all around the ice sheet are instead related to the astronomical timescale we also perform simulations including a glacial flow scheme which shows that the sputnik planitia ice sheet is currently at its minimum extent at the northern and southern edges we also explore the stability of n2 ice deposits outside the latitudes and longitudes of the sputnik planitia basin results show that n2 ice is not stable at the poles but rather in the equatorial regions in particular in depressions where thick deposits may persist over tens of millions of years before being trapped in sputnik planitia finally another key result is that the minimum and maximum surface pressures obtained over the simulated millions of years remain in the range of milli pascals and pascals respectively this suggests that pluto never encountered conditions allowing liquid nitrogen to flow directly on its surface instead we suggest that the numerous geomorphological evidences of past liquid flow observed on pluto s surface are the result of liquid nitrogen that flowed at the base of thick ancient nitrogen glaciers which have since disappeared

nature and significance of late cretaceous ophiolitic rocks and their relation to the baskil granitic intrusions of the elazig region se turkey

the temporal evolution of the active margin along the southeast anatolian orogenic belt se turkey evidence from u pb ar ar and fission track chronology abstract the southeast anatolian orogenic belt saob resulted from the north dipping subduction of the southern neotethyan oceanic lithosphere in late mesozoic and early cenozoic however the timing and the rate of the continental collision are still under debate here we present new u pb ar ar and fission track ages from the i type calc alkaline granitoids esence dogansehir and baskil cutting the goksun ispendere and komurhan ophiolites and also the malatya keban metamorphics representing the tauride active continental margin along the saob in this study high to low temperature thermochronological methods applied to the granitoids are used to understand the temporal and geodynamic evolution of the tauride active continental margin and continental collision between tauride and arabian platforms in the frame of the neotethyan convergence during cretaceous and miocene the u pb zircon ages range from 83 to 88 ma for the baskil and from 81 to 83 ma for the esence granitoids the 39 ar 40 ar ages indicate that these late cretaceous granitoids cooled below 300 c in 6 10 ma the formation ages and the timing of the gradual cooling of the late cretaceous granitoids are similar to metamorphism age and the timing of the exhumation of the hp lt bitlis metamorphics during this stage the combined field geochemistry and geo thermochronological data suggest that the first continental collision event occurred between bitlis puturge micro continents to the south and tauride platform to the north in an oblique subduction zone between 84 and 74 ma the granitoids continued uplifting during early middle eocene together with the exhumation of hp uht berit metaophiolite in an extensional regime related to the opening of the maden back arc basin this period also let the intrusion of the dogansehir arc magmatism intruding the puturge and malatya keban metamorphics berit metaophiolite and maden complex the eocene dogansehir granitoid has similar u pb and 39 ar 40 ar ages suggesting a fast cooling the apatite fission track aft ages for all granitoid bodies suggest that they were mainly cooled or uplifted in two episodes where the first one is in the eocene in an extensional setting the aft data marked the final continental collision between the taurides and the arabian platform first in oligocene and the break off of the subducted slab and the delamination process caused fast uplift of the eastern anatolia during middle to late miocene

ophiolitic and metamorphic assemblages of southeast anatolia and their significance in the geological evolution of the orogenic belt the southeast anatolian orogen may be divided into three roughly east west trending structural zones formed as a result of continental collision between the taurus platform and the arabian continent along the orogenic belt metamorphic and ophiolitic rocks occur widely the ophiolites represent remnants of the ocean or oceans which were totally consumed between these converging continental blocks during late cretaceous to miocene period metamorphic rocks formed from the oceanic as well as the continental rocks which were incorporated into a nappe stack during the consumption of the oceanic lithosphere and the progressive southward advance of the nappes toward the arabian continent the metamorphic units together with the ophiolite associations provide stratigraphic and petrologic evidence indicating time place and environment of formation of these units the metamorphic units also provide evidence of nappe transportation stages which are complementary to the data derived from the sedimentary successions in the evaluation of the orogenic evolution of southeast anatolian orogen

stratigraphy of cretaceous to lower pliocene sediments in the northern part of cyprus based on comparative 87sr 86sr isotopic nannofossil and planktonic foraminiferal dating new age data from sr isotope analysis and both planktonic foraminifera and nannofossils are presented and discussed here for the upper eocene upper miocene sedimentary rocks of the degirmenlik kythrea group new dating is also given of some cretaceous and pliocene sediments in a revised stratigraphy the degirmenlik kythrea group is divided into ten formations different upper miocene formations are developed to the north and south of a regionally important e w trending syn sedimentary fault the samples were dated wherever possible by three independent methods namely utilizing sr isotopes calcareous nannofossils and planktonic foraminifera some of the sr isotopic dates are incompatible with the nannofossil and or the planktonic foraminiferal dates this is mainly due to reworking within gravity deposited or current affected sediments when combined the reliable age data allow an overall biostratigraphy and chronology to be erected several of the boundaries of previously defined formations are revised sr data that are incompatible with well constrained biostratigraphical ages are commonly of early miocene age this is attributed to a regional uplift event located to the east of cyprus specifically the collision of the anatolian eurasian and arabian african plates during early miocene time this study therefore demonstrates that analytically sound sr isotopic ages can yield geologically misleading ages particularly where extensive sediment reworking has occurred convincing ages are obtained when isotopic dating is combined with as many forms of biostratigraphical dating as possible and this may also reveal previously unsuspected geological events e g tectonic uplift or current activity

late eocene neogene sedimentary geology of the girne kyrenia range northern cyprus a case history of sedimentation related to progressive and diachronous continental collision abstract sedimentary geology can shed light on the processes of continental collision the easternmost mediterranean provides an exceptional opportunity to study sediments deposited during progressive and diachronous continental collision with implications for comparable settings elsewhere here we focus on sediment sources pathways and deposition of mostly deep sea clastic sediments exposed in northern cyprus the sedimentary basin forms part of the northern continental margin of the southern neotethys ocean and is represented by a ca 200 km long e w trending arcuate lineament encompassing northern cyprus and its submarine link with turkey the upper eocene upper miocene basin was divided into northerly and southerly sub basins during mid to late miocene time by an e w trending inferred syn depositional fault lineament the sequence begins with non marine to shallow marine basal conglomerates late eocene that abruptly fine upwards into siliciclastic turbidites oligocene followed by biogenic calciturbidites and marls aquitanian langhian during mid late miocene the northerly sub basin was characterised by thin to medium bedded calciturbidites and marls serravallian overlain by thick bedded medium grained lithic sandstones tortonian in contrast the southern sub basin is dominated by siliciclastic turbidites with abundant sole structures burdigalian tortonian palaeocurrent evidence indicates dominantly westward sediment transport especially during the late miocene the serravallian tortonian sandstones of the northern sub basin are relatively rich in carbonates while the southern sub basin contains more siliciclastic and ophiolite derived detritus indicating differences in sediment supply in general the upper eocene basal conglomerates were mainly derived from the north from within the girne kyrenia range and its inferred northward extension in response to rapid subsidence reflecting possible southward subduction zone retreat clastic sediment sources to the north then submerged while clastic sediment was instead mainly supplied from the south neotethyan suture zone to the east and northeast in southern turkey reflecting diachronous collision deep water deposition persisted in the easternmost mediterranean basin further west until this was terminated in northern cyprus by thrusting folding during latest miocene earliest pliocene quaternary collision related uplift ensued similar sedimentary development is to be expected in collisional settings elsewhere e g tethyan closure in the himalayas iapetus closure in the appalachians

the rapid formation of sputnik planitia early in pluto s history modelling suggests that the icy region on pluto known as sputnik planitia formed shortly after charon did and has since been stable with its latitude corresponding to a minimum in annual solar illumination and its longitude determined by tidal forces from charon douglas hamilton et al present modelling data that imply that pluto s sputnik planitia basin may be an ice cap rather than the product of an impact their data suggest that the feature formed shortly after pluto s largest satellite charon did and has since been stable with its latitude corresponding to a minimum in annual solar illumination over its orbital precession period of about a million years and its longitude determined by tidal forces from charon this is one of four papers on the geology of sputnik planitia in this issue of nature in news views amy barr puts these latest contributions into context pluto s sputnik planitia is a bright roughly circular feature that resembles a polar ice cap it is approximately 1 000 kilometres across and is centred on a latitude of 25 degrees north and a longitude of 175 degrees almost directly opposite the side of pluto that always faces charon as a result of tidal locking1 one explanation for its location includes the formation of a basin in a giant impact with subsequent upwelling of a dense interior ocean2 once the basin was established ice would naturally have accumulated there3 then provided that the basin was a positive gravity anomaly with or without the ocean true polar wander could have moved the feature towards the pluto charon tidal axis on the far side of pluto from charon2 4 here we report modelling that shows that ice quickly accumulates on pluto near latitudes of 30 degrees north and south even in the absence of a basin because averaged over its orbital period those are pluto s coldest regions within a million years of charon s formation ice deposits on pluto concentrate into a single cap centred near a latitude of 30 degrees owing to the runaway albedo effect this accumulation of ice causes a positive gravity signature that locks as pluto s rotation slows to a longitude directly opposite charon once locked charon raises a permanent tidal bulge on pluto which greatly enhances the gravity signature of the ice cap meanwhile the weight of the ice in sputnik planitia causes the crust under it to slump creating its own basin as has happened on earth in greenland5 even if the feature is now a modest negative gravity anomaly it remains locked in place because of the permanent tidal bulge raised by charon any movement of the feature away from 30 degrees latitude is countered by the preferential recondensation of ices near the coldest extremities of the cap therefore our modelling suggests that sputnik planitia formed shortly after charon did and has been stable albeit gradually losing volume over the age of the solar system

primordial n2 provides a cosmochemical explanation for the existence of sputnik planitia pluto abstract the presence of n2 in the surface environment of pluto is critical in creating pluto s richness of features and processes here we propose that the nitrogen atoms in the n2 observed on pluto were accreted in that chemical form during the formation of pluto we use new horizons data and models to estimate the amounts of n2 in the following exterior reservoirs atmosphere escape photochemistry and surface the total exterior inventory is deduced to be dominated by a glacial sheet of n2 rich ices at sputnik planitia or by atmospheric escape if past rates of escape were much faster than at present pluto s atmosphere is a negligible reservoir of n2 and photochemical destruction of n2 may also be of little consequence estimates are made of the amount of n2 accreted by pluto based on cometary and solar compositions it is found that the cometary model can account for the amount of n2 in sputnik planitia while the solar model can provide a large initial inventory of n2 that would make prodigious atmospheric escape possible these consistencies can be considered preliminary evidence in support of a primordial origin of pluto s n2 however both models predict accreted ratios of co n2 that are much higher than that in pluto s atmosphere possible processes to explain missing co that are given quantitative support here are fractional crystallization from the atmosphere resulting in co burial at the surface and aqueous destruction reactions of co subject to metastable thermodynamic equilibrium in the subsurface the plausibility of primordial n2 as the primary source of pluto s nitrogen vs nh3 or organic n can be tested more rigorously using future constraints on the 14 n 15 n ratio in n2 and the 36ar n2 ratio

age and tectonomagmatic setting of the eocene copler kabatas magmatic complex and porphyry epithermal au deposit east central anatolia turkey the copler epithermal au deposit and related subeconomic porphyry cu au deposit is hosted by the middle eocene copler kabatas magmatic complex in central eastern anatolia the intrusive rocks of the complex were emplaced into late paleozoic mesozoic metamorphosed sedimentary basement rocks near the northeastern margin of the tauride anatolide block igneous biotite from two samples of the magmatic complex yielded 40ar 39ar plateau ages of 43 75 0 26 ma and 44 19 0 23 whereas igneous hornblende from a third sample yielded a plateau age of 44 13 0 38 these ages closely overlap with 40ar 39ar ages of hydrothermal sericite 44 44 0 28 ma and biotite 43 84 0 26 ma and re os ages from two molybdenite samples 44 6 0 2 and 43 9 0 2 ma suggesting a short lived 1 my magmatic and hydrothermal history at copler no suitable minerals were found that could be used to date the epithermal system but it is inferred to be close in age to the precursor porphyry system the copler kabatas intrusive rocks show i type calc alkaline affinities their normalized trace element patterns show enrichments in large ion lithophile and light rare earth elements and relative depletions in middle and heavy rare earth elements resembling magmas generated in convergent margins however given its distance from the coeval eocene maden helete volcanic arc the complex is interpreted to be formed in a back arc setting in response to paleocene slab roll back and upper plate extension the tectonomagmatic environment of porphyry epithermal mineralization at copler is comparable to some other isolated back arc porphyry systems such as bajo de la alumbrera argentina or bingham canyon usa

new paleomagnetic results from upper cretaceous arc type rocks from the northern and southern branches of the neotethys ocean in anatolia a paleomagnetic study of cretaceous arc type rocks in the central eastern pontides and in the southeastern taurides investigates the tectonic and paleolatitudinal evolution of three volcanic belts in anatolia namely the northern and southern volcanic belts in the pontides and the se taurides volcanic belt the paleomagnetic data indicate that magnetizations were acquired prior to folding at most sampling localities sites except for those in the erzincan area in the eastern pontides the southern volcanic belt was magnetized at a paleolatitude between 23 8 3 8 4 2 n and 20 2 1 2 1 3 n hisarli j geodyn 52 114 128 2011 reported a more northerly paleolatitude 26 6 4 6 5 1 n for the northern volcanic belt the comparison of the new paleomagnetic results with previous ones in anatolia allows to conclude that the southern volcanic belt in the central eastern pontides was emplaced after the northern volcanic belt as a result of slab roll back of the northern neotethys ocean in the late cretaceous in the southeast taurides upper cretaceous arc related sandstones were at a paleolatitude of 16 8 3 8 4 2 the late cretaceous paleomagnetic rotations in the central pontides exhibit a counterclockwise rotation of r pm delta r 37 1 circ pm 5 8 circ group 1 cankiri yaylacayi formation while maastrichtian arc type rocks in the yozgat area group 2 show clockwise rotations r r 33 7 8 4 and r r 29 3 6 0 in the se taurides counterclockwise and clockwise rotations of r pm delta r 48 6 text circ text pm 5 2 text circ text and r pm delta r 34 1 text circ text pm 15 1 text circ text are obtained group 4 elazig magmatic complex the late cretaceous paleomagnetic rotations in the pontides follow a general trend in concordance with the shape of the suture zone after the collision between the pontides and the kirsehir block the affect of the westwards excursion of the anatolian plate and the associated fault bounded block rotations in miocene are observed in the east of the study area and the se taurides

andean type active margin formation in the eastern taurides geochemical and geochronogical evidence from the baskil granitoid elazig se turkey abstract the southeast anatolian orogen resulted from collision of the afro arabian and the eurasian plates following the cretaceous to miocene closure of the southern neotethyan oceanic basin in this orogenic belt there are number of tectonomagmatic stratigraphic units in the kahramanmaras malatya elazig region that are important to understand the geological evolution of southeast anatolia during the late cretaceous these are a metamorphic massifs i e malatya keban platform b ophiolites i e goksun ispendere komurhan c ophiolite related metamorphics i e berit metaophiolite and d granitoids i e goksun dogansehir and baskil the baskil granitoid crops out to the northwest of elazig and is a large magmatic body 170 km2 that intruded all of the above mentioned units during late cretaceous time the baskil granitoid comprises both mafic and felsic plutonic sub plutonic rock associations the felsic plutonic phase includes granite granodiorite tonalite and quartz monzonite whereas the felsic sub plutonic phase is characterized by aplite granophyre granite porphyry and granodiorite porphyry the granite and granodiorite contain mafic microgranular enclaves mme the mafic plutonic phase comprises gabbro diorite quartz diorite whereas the mafic sub plutonic phase is represented by diabase microdiorite quartz microdiorite diorite porphyry quartz diorite porphyry and dykes of orbicular gabbro dyke geochemically the baskil granitoid rocks have i type metaluminous peraluminous calc alkaline characteristics the ree and ocean ridge granite normalized multi element patterns and tectonomagmatic discrimination diagrams together with biotite geochemistry suggest that the granitoids were formed in a volcanic arc setting the40ar 39ar geochronology of the granitoid rocks yielded biotite ages of 81 9 0 7 ma and 81 5 0 8 ma 95 confidence level coexisting hornblende and hornblende from additional samples yielded ages ranging from 84 0 0 7 ma to 81 5 1 1 ma the ophiolites are believed to have formed in a suprasubduction zone tectonic setting whereas the ophiolite related metamorphic rocks formed either during the initiation of intraoceanic subduction or later stage thrusting 90 ma these units were then thrust beneath the malatya keban platform during the progressive closure of the southern neotethys this was followed by intrusion of the granitoids 85 82 ma along the tauride active continental margin of the southern neotethys

tectonic magmatic and metallogenic evolution of the tethyan orogen from subduction to collision abstract this paper reviews the tectonic magmatic and metallogenic history of the tethyan orogen from the carpathians to indochina focus is placed on the formation of porphyry cu mo au deposits as being the most characteristic mineral deposit type formed during both subduction and collisional processes in this region relatively little is known about the history of the paleotethys ocean which opened and closed between gondwana and eurasia in the paleozoic and few ore deposits are preserved from this period the neotethyan ocean opened in the permian early triassic as the cimmerian continental fragments the cores of turkey iran tibet and indochina rifted from the northern gondwana margin and drifted northwards these microcontinents docked with the eurasian margin at various points in the mesozoic and cenozoic and formed a complex archipelago involving several small back arc basins and remnants of the paleotethyan ocean the main neotethyan ocean and these smaller basins were largely eliminated by collision with india and africa arabia in the early eocene and early mid miocene respectively although neotethyan subduction continues beneath the hellenic arc and the makran the majority of porphyry type deposits are found in association with neotethyan subduction mainly in the mesozoic and paleogene and syn to post collisional events in the mid paleogene to neogene they are found throughout the orogen but some sections are particularly well endowed including the carpathians balkans rhodopes eastern turkey lesser caucasus nw iran se iran sw pakistan southern tibet and se tibet indochina other sections that appear barren may reflect deeper levels of erosion young sedimentary cover or lack of exploration although there may also be real reasons for low prospectivity in some areas such as minimal subduction e g the western mediterranean region or lithospheric underthrusting as proposed in western tibet over the last decade improved geochronological constraints on the timing of ore formation and key tectonic events have revealed that many porphyry deposits that were previously assumed to be subduction related are in fact broadly collision related some forming in back arc settings in advance of collision some during collision and others during post collisional processes such as orogenic collapse and or delamination of subcontinental mantle lithosphere while the formation of subduction related porphyries is quite well understood collisional metallogeny is more complex and may involve a number of different processes or sources these include melting of orogenically thickened crust previously subduction modified lithosphere including metasomatized mantle underplated mafic rocks or lower crustal arc plutons and cumulates or upwelling asthenosphere e g in response to delamination slab breakoff back arc extension or orogenic collapse the most fertile sources for syn and post collisional porphyry deposits appear to be subduction modified lithosphere because these hydrated lithologies melt at relatively low temperatures during later tectonomagmatic events and retain the oxidized and relatively metalliferous character of the original arc magmatism unusually metallically enriched lithospheric sources do not seem to be required but the amount of residual sulfide phases in these rocks may control metal ratios e g cu au in subsequent magmatic hydrothermal ore deposits relatively au rich deposits potentially form in these settings as observed in the carpathians e g rosia montan turkey kisladag copler and iran sari gunay dalli although the majority of syn and post collisional porphyries are cu mo rich and resemble normal subduction related deposits e g in the gangdese belt of southern tibet this similarity extends to the associated igneous rocks which being derived from subduction modified sources largely retain the geochemical and isotopic character of those original arc magmas while still retaining a broadly calc alkaline character these rocks may extend to mildly alkaline shoshonitic compositions and may display adakite like trace element signatures high sr y and la yb ratios reflecting melting of deep crustal garnet amphibolitic sources but they are otherwise hard to distinguish from normal subduction related magmas small post collisional mafic alkaline volcanic centers are common throughout the orogen but for the most part appear to be barren however similar rocks in other post subduction settings around the world are associated with important alkalic type porphyry and epithermal au cu deposits and the potential for discovery of such deposits in the tethyan orogen should not be overlooked

the pluto system initial results from its exploration by new horizons the pluto system was recently explored by nasa s new horizons spacecraft making closest approach on 14 july 2015 pluto s surface displays diverse landforms terrain ages albedos colors and composition gradients evidence is found for a water ice crust geologically young surface units surface ice convection wind streaks volatile transport and glacial flow pluto s atmosphere is highly extended with trace hydrocarbons a global haze layer and a surface pressure near 10 microbars pluto s diverse surface geology and long term activity raise fundamental questions about how small planets remain active many billions of years after formation pluto s large moon charon displays tectonics and evidence for a heterogeneous crustal composition its north pole displays puzzling dark terrain small satellites hydra and nix have higher albedos than expected

geological mapping of sputnik planitia on pluto abstract the geology and stratigraphy of the feature on pluto informally named sputnik planitia is documented through geologic mapping at 1 2 000 000 scale all units that have been mapped are presently being affected to some degree by the action of flowing n2 ice the n2 ice plains of sputnik planitia display no impact craters and are undergoing constant resurfacing via convection glacial flow and sublimation condensation of atmospheric n2 onto the surface to form a bright mantle has occurred across broad swathes of sputnik planitia and appears to be partly controlled by pluto s obliquity cycles the action of n2 ice has been instrumental in affecting uplands terrain surrounding sputnik planitia and has played a key role in the disruption of sputnik planitia s western margin to form chains of blocky mountain ranges as well in the extensive erosion by glacial flow of the uplands to the east of sputnik planitia

structure and deformation history of the bitlis suture near lake hazar southeastern turkey detailed mapping of the bitlis suture zone near lake hazar shows that it is composed of three tectonostratigraphic units which crop out as distinct north dipping thrust slices from south to north these are the puturge metamorphic complex the maden melange and the elazig igneous complex the puturge metamorphic complex consists of pre tertiary continental margin sediments metamorphosed to the greenschist facies during the campanian maastrichtian and deformed by four generations of structures these are in sequence 1 isoclinal folds and a transposition foliation 2 open folds crenulation cleavage and north dipping thrust faults 3 kink bands and 4 small displacement faults the maden melange represents middle eocene back arc basin sediments and volcanics metamorphosed to the greenschist facies and deformed by three generations of structures 1 a north dipping cleavage 2 kink bands and 3 small displacement faults the elazig igneous complex comprises an imbricated maastrichtian early eocene island arc and young marginal basin terrain thrust faults between units are north dipping listric and form a thin skinned system these features suggest the following deformational and tectonic history the puturge metamorphic complex was generated by isoclinal folding and metamorphism of sediments composing the arabian continental margin during campanian maastrichtian ophiolite obduction to the south the elazig arc developed on the deformed margin because of subsequent southward subduction of oceanic lithosphere the arc migrated to the north opening a back arc basin by the early eocene the back arc basin was filling with volcaniclastics of the maden melange and the elazig arc collided with a continent to the north during middle to late eocene convergence caused thrust stacking of the elazig maden and puturge complexes second generation deformation in the puturge complex and first generation deformation in the maden melange continued convergence with the arabian plate in the late miocene caused kink banding in the puturge and maden complexes since the late miocene this convergence has been accommodated by shortening and thickening along numerous internal faults

mesozoic sedimentary and magmatic evolution of the arabian continental margin northern syria evidence from the baer bassit melange one of the few detailed records of mesozoic deep water sedimentation and volcanism preserved along the tectonically emplaced arabian continental margin is from the baer bassit region of northern syria south tethyan units there occur as blocks broken formation and disrupted thrust sheets within the bear bassit melange two overall composite successions are identified the first comprises mainly sedimentary successions ranging from late triassic to late cretaceous cenomanian in age the second is dominated by middle jurassic lower cretaceous alkaline per alkaline volcanic and minor intrusive igneous rocks the extrusives are intercalated with radio larian sediments and capped by cenomanian ferromanganese rich pelagic limestone facies compari sons and the regional setting suggest that the triassic to cenomanian mainly sedimentary units formed in deep water near the base of the slope of the arabian continental margin the contrasting volcanogenic successions developed in a more distal off margin setting regional comparisons e g with southwestern cyprus and southwestern turkey suggest that continental break up to form a south tethyan oceanic basin took place in late triassic time associated with alkaline volcanism similar alkaline volcanism of middle jurassic to early cretaceous age could reflect the activity of a mantle plume beneath the arabian plate overall sedimentation was mainly controlled by an interplay of post rift thermal subsidence plume related uplift siliceous oceanic productivity climatic change and eustatic sea level change the south tethyan marginal to oceanic units in northern syria were detached from an inferred oceanic basement in latest cretaceous time emplaced onto the arabian continental margin then transgressed by maastrichian and younger autochthonous successions

the tectonic history of kohistan and its implications for himalayan structure the tectonic history of kohistan northern pakistan involves two collisional events cleavage and folding developed at 90 100 ma along the northern suture between the kohistan island arc and the asian plate at the same time there was major folding and shearing of the lower part of the kohistan arc approximately 100 km south of the suture this deformation was followed by ocean subduction south of the kohistan arc generating the kohistan calc alkaline batholith with subsequent ocean closure during the eocene and obduction of the kohistan arc together with the adjacent part of the asian plate over the indian continental crust the construction of balanced cross sections through the imbricated upper part of the indian continental crust in the footwall to this southern suture indicates a minimum displacement of 470 km requiring the western himalayan hinterland to be underlain by a large wedge of indian middle to lower crust there is some shortening of the overriding kohistan and asian plates by thrusts and shear zones but it is insufficient to satisfy the palaeomagnetic data there must be major crustal shortening involving thrusts in the hindu kush and pamirs north of kohistan the post eocene thrust direction which for most of pakistan is towards 160 is almost perpendicular to that immediately to the east in the himalayan belt generating complex refolded thrust patterns in the hazara syntaxis and large scale folding and rapid uplift with associated brittle faulting and seismic activity adjacent to the nanga parbat syntaxis these different thrust trends indicate that major thrust movement as well as the folds and deformation fabrics cannot always be related to plate movement vectors but are modified by or develop from complex rotations during place collision or from the gravitational spreading of a thickened crust a regional approach is required to recognize and correctly attribute the various components in thrust displacements

pluto s climate modeled with new observational constraints abstract pluto has a nitrogen atmosphere in vapor pressure equilibrium with surface ice n 2 is mobile and is transported seasonally even at pluto s cold temperatures in the outer solar system a thermal model developed by hansen and paige in 1996 to model pluto s climate has been re deployed in response to new data and in anticipation of the new horizons flyby of pluto in 2015 a number of stellar occultations have been observed in the last 11 years as pluto has crossed the galactic plane new hubble space telescope images show a variegated surface these recent observations allow us to model pluto s climate with much tighter constraints our findings suggest that pluto s atmosphere will not collapse prior to the arrival of new horizons although pressure will be dropping as n 2 condenses on the south polar cap this finding is in contrast to the olkin et al olkin et al 2013 arxiv1309 0841o prediction that permanent volatiles in the northern hemisphere maintain pluto s atmospheric pressure throughout its orbit the range of surface pressures predicted for 2015 for nine cases with very good matches to observables is 0 3 3 2 pa the best match predicts that new horizons will detect an atmospheric pressure of 2 4 pa

petrology of a supra subduction zone ophiolite elaz1g turkey the elazig region in eastern taurus turkey exposes paleozoic tertiary metamorphic magmatic and sedi mentary units contacts between the different units are mostly tectonic but there are also primary sedimentary and in trusive contacts the metamorphic rocks of the elazig region are the bitlis puturge and keban malatya massifs which are a single tectonostratigraphic unit that has been tectonically disrupted and fragmented during the upper cretaceous magmatic rocks in the region are represented by ophiolitic units magmatic arc products and young volcanic rocks the sedimentary units are represented by upper cretaceous tertiary marine and lacustrine sedimentary rocks in the study area the metamorphic units are represented by the paleozoic puturge metamorphic rocks composed of phyllite slate mica schist quartz muscovite schist calc schist and low grade metamorphite the ophiolite that is described in this paper is composed of wehrlite pyroxenite gabbro diabase dykes and dykes cutting gabbro these units are cut by the granitic rocks of the upper cretaceous elazig magmatic suite the lithological and geochemical data on the rocks of komurhan ophiolite indicate that these rocks were derived from crystallization of an enriched mid ocean ridge basalt morb type magma the komurhan ophiolite formed in a supra subduction spreading zone during the cretaceous re lated to this event is the north dipping subduction of the southern branch of neo tethys ocean which began spreading in the late triassic the crust was thickened by the development of an island arc and by the thrusting of the puturge metamorphic rocks onto this island arc in response to north south compression during the late cretaceous the magma formed by partial melting of the subducted slab giving rise to granitic rocks that cut the upper parts of the ophiolite the ophiolite and the elazig magmatic suite attained their present position after the middle eocene

new evidence and solution to the maden complex controversy of the southeast anatolian orogenic belt turkey the volcanosedimentary units of late mesozoic tertiary age that outcrop in the southeast anatolian orogenic belt are commonly referred to as the maden complex there is a long lasting controversy over its definition age stratigraphic and structural position and the origin and thus the orogenic evolution to solve this problem large strips across the southeast anatolian orogenic belt have been studied extensively and different rock groups which were regarded previously as the maden unit have been differentiated their major characteristics and differences have been identified the maden unit sensu stricto is here redefined as a volcanosedimentary succession of middle eocene age representing a short lived back arc basin which reached the stage of an embryonic ocean presently the maden group occurs mainly within the lower nappe stack of the nappe zone of the southeast anatolian orogen it rests stratigraphically on an amalgamated nappe package consisting of the different metamorphic tectonic units and in turn is overlain tectonically by the upper nappe units

pluto s haze as a surface material pluto s atmospheric haze settles out rapidly compared with geological timescales it needs to be accounted for as a surface material distinct from pluto s icy bedrock and from the volatile ices that migrate via sublimation and condensation on seasonal timescales this paper explores how a steady supply of atmospheric haze might affect three distinct provinces on pluto we pose the question of why they each look so different from one another if the same haze material is settling out onto all of them cthulhu is a more ancient region with comparatively little present day geological activity where the haze appears to simply accumulate over time sputnik planitia is a very active region where glacial convection as well as sublimation and condensation rapidly refresh the surface hiding recently deposited haze from view lowell regio is a region of intermediate age featuring very distinct coloration from the rest of pluto using a simple model haze particle as a colorant we are not able to match the colors in both lowell regio and cthulhu to account for their distinct colors we propose that after arrival at pluto s surface haze particles may be less inert than might be supposed from the low surface temperatures they must either interact with local materials and environments to produce distinct products in different regions or else the supply of haze must be non uniform in time and or location such that different products are delivered to different places

volcanism sedimentation and massive sulfide mineralization in a late cretaceous arc related basin eastern taurides turkey abstract late cretaceous arc volcanism and associated massive sulfide mineralizations occur in the eastern taurus mountains the mineralizations are related to felsic dacitic rhyolitic volcanic rocks which together with basement rocks form the lowermost levels of a 5000 m thick volcano sedimentary sequence and are restricted to a few levels within the sequence basaltic rocks which are intruded by tonalite and dacite form the base of the volcano sedimentary sequence the dacitic rhyolitic rocks are overlain by a volcano sedimentary succession with andesitic dacitic flows the flows do not contain any mineralization this succession starts with volcanic breccia and tuffs at the base passing into crystal rich sandstone and pelagic mudstone with tuffite intercalations and ends with marls intercalated with sandstones basalt and peridotite olistoliths the felsic rocks bear stockwork and disseminated types of mineralization the massive sulfide mineralization has a simple mineral assemblage of pyrite chalcopyrite bornite and sphalerite optical microscopic examination of pyrites from derince massive sulfide deposits reveals that the pyrites are commonly seen in framboidal and cubic forms the geochemistry of the magmatic rocks and sedimentary facies associations indicate that the mineralizations in the derince were developed in an intra arc environment

testing models of late palaeozoic early mesozoic orogeny in western turkey support for an evolving open tethys model field evidence from north south transects tests three tectonic models for tethys in western turkey for when a late palaeozoic ocean was closing and an early mesozoic ocean opening in model 1 a palaeozoic ocean subducted southwards rifting continental fragments from gondwana and opening a triassic neo tethys to the south closure and collision occurred by latest triassic time in model 2 a wide palaeozoic tethys subducted northwards with an active eurasian margin and a passive gondwana margin the northern gondwana margin rifted in the triassic fragments either remained nearby taurides or drifted northwards e g karakaya attached to a north subducting plate new oceanic crust replaced palaeo tethys with neotethys and back arc marginal basins opened along the south eurasian margin e g kure in model 3 a palaeozoic ocean also subducted northwards opening wide marginal basins a wide southern neotethys opened along the gondwana margin rifted eurasian anatolides and gondwana taurides fragments collided in mid tethys by latest triassic time field evidence from the pontides supports north dipping subduction models model 2 or 3 above key features are a south vergent hp lt accretionary prism magmatic arc and back arc basin system bordering the eurasian margin also evidence from the tauride mountains favours model 2 over model 3 critically the anatolides and taurides appear to have a common history and were unlikely to have been located on opposite sides of tethys as in model 3

sedimentary development of the oligocene karsanti basin southern turkey in its regional tectonic setting abstract following late cretaceous ophiolite and melange emplacement within the tauride belt several neogene sedimentary basins of variable size were formed along the southern flank of the taurus continent in southern turkey these include the pozanti and karsanti basins and the regional scale cukurova basin complex extending southwestwards into the cilicia kyrenia basin the karsanti basin is bounded by the regional scale sinistral ecemis fault zone to the west the east anatolian fault zone to the southeast and the negoene adana basin to the south deformed palaeozoic and mesozoic rock units that display an irregular palaeotopography form the basement of the karsanti basin these units are overlain by an allochthonous kizildag melange and by thrust slices of basic ultrabasic ophiolitic rocks farasa ophiolites that were emplaced in this region during the late maastrichtian the karsanti basin was formed during the oligocene above the thrust sheets the karsanti basin disconformably overlies the ophiolitic nappes and is interpreted as a n s trending half graben which was probably most active following the deposition of lacustrine sediments during the late oligocene the main karsanti basin infill is represented by four lithological units 1 alluvial fan deposits a1 2 shallow marine deposits a2 3 lacustrine deposits a3 and 4 fluvial deposits a4 these sediments were deposited during the oligocene prior to the initiation of the main adana basin which formed in a separate intermontane setting the karsanti basin fill is unconformably overlain by early miocene sediments of the neogene adana basin

stable asymmetric ice belts in an energy balance model of pluto abstract in this paper we analyze a latitude dependent energy balance model with two dynamic ice lines between the north and south poles and consider results for a range of parameter values of which some may pertain to pluto our analysis shows that for any albedo contrast there exist stable ice line equilibria where the northern and southern edges are not symmetric about the equator in particular stable asymmetric ice belts can be found within the latitude ranges defined by sputnik planitia on pluto however we find that an ice belt with northern and southern edges defined by the northern and southern boundaries of sputnik planitia would be flowing to a symmetrical configuration for the parameter values used in this study