garnet and tourmaline as provenance indicators of terrigenous material in epicontinental carbonates middle triassic s poland abstract heavy mineral grains contained in epicontinental carbonates are very rarely used for provenance analysis this study deals with detrital heavy minerals separated from marly limestones and marlstones of the gogolin formation gf middle triassic s poland to determine their source rocks and alimentary areas the gf carbonates typically contain 1 wt of heavy minerals within the very fine sand fraction the heavy mineral assemblages consist predominantly of garnets 53 0 92 2 and tourmalines 3 8 30 4 epma analyses reveal four groups of garnets low grs almandines with 30 50 mol prp almandines with 20 35 mol prp and up to 35 mol grs almandines with up to 20 mol sps and rare pyrope grains 60 mol prp the composition of the garnets indicates that hp felsic granulites were their main source rocks but more mafic hp rocks eclogites retrograded eclogites and mafic granulites gneisses mica schists and garnet peridotites also contributed the detrital tourmalines are represented mainly by dravite and less frequently by schorl which were derived mostly from paragneisses and mica schists and in minor part from granitoids and pegmatites the e ne part of the bohemian massif is the most probable location of the source rocks the presumed source rocks presently outcrop in the moldanubian zone the kutna hora unit the svratka unit and the gory sowie massif nowadays the bodies formed by the hp rocks within these units are insufficiently large to act as sources for delivering detrital material in the determined proportions the high content of hp metamorphic grains thus indicates the past existence of extensively exposed and abundant high pressure metamorphic rocks eroded during and or after the middle triassic

southwest pacific deep water carbonate chemistry linked to high southern latitude climate and atmospheric co2 during the last glacial termination abstract a greater amount of co2 was stored in the deep sea during glacial periods likely via greater efficiency of the biologic pump and increased uptake by a more alkaline ocean reconstructing past variations in seawater carbonate ion concentration a major component of alkalinity enables quantification of the relative roles of different oceanic co2 storage mechanisms and also places constraints on the timing magnitude and location of subsequent deep ocean ventilation here we present a record of deep water inorganic carbon chemistry since the last glacial maximum lgm 19 23 ka bp derived from sediment core rr0503 83 raised from 1627 m in new zealand s bay of plenty the core site lies within the upper limit of southern sourced circumpolar deep water cdw just below the lower boundary of antarctic intermediate water aaiw we reconstruct past changes in bottom water inorganic carbon chemistry from the trace element and stable isotopic composition of calcite shells of the epibenthic foraminifer cibicidoides wuellerstorfi a record of co 3 2 co 3 2 co 3 2 i n s i t u co 3 2 saturation derived from the foraminiferal boron to calcium ratio b ca provides evidence for greater ice age storage of respired co2 and reveals abrupt deglacial shifts in co 3 2 i n s i t u of up to 30 mol kg 5 times larger than the difference between average lgm and holocene values the rapidity of these changes suggests the influence of changing water mass structure and atmospheric circulation in addition to a decrease in co2 content of interior waters

seismic and gpr surveys of mullins glacier mcmurdo dry valleys antarctica ice thickness internal structure and implications for surface ridge formation we present results from ground penetrating radar gpr and seismic surveys for the mullins valley debris covered glacier mullins glacier antarctica that yield local ice thickness estimates of 80 110 m in upper mullins valley and 150 m in upper beacon valley englacial debris in upper mullins glacier occurs as scattered cobbles and as discrete layers one extensive englacial debris layer which appears as a coherent reflector dipping 40 458 up valley intersects the ground surface within an 8m high ice cored ridge the largest of several ridges that mark the glacier surface field excavations reveal that this englacial interface consists of multiple debris bands that can be directly correlated with ridge microtopography englacial debris layers most probably originate as concentrated rockfall in ice accumulation zones and or as surface lags that form as dirty ice sublimes during periods of negative mass balance a similar pattern of surface ridges on friedman glacier 2 5 km west of mullins glacier suggests regional environmental changes are involved in ridge formation these observations carry implications for evaluating debris entrainment and surface ridge formation mechanisms in cold based debris covered glaciers and provide a glaciological framework for evaluating and interpreting paleoclimate records from mullins glacier

cretaceous to cenozoic thermal evolution of the southwestern south carpathians evidence from fission track thermochronology abstract the southwestern south carpathian orogen is composed of various nappe complexes which were assembled during the cretaceous cenozoic orogeny these are from footwall to hangingwall 1 the danubian nappe complex including a cadomian variscan basement 2 the arjana and severin units with jurassic to early cretaceous rift and oceanic sequences and 3 the getic nappe complex with variscan continental basement fission track ft thermochronology on apatite zircon and sphene from samples collected from various units of the south carpathians in conjunction with field constraints and previous geochronology is used to characterise the alpine tectonic events and to restore the pattern and amount of exhumation since the cretaceous zircon from the flysch unit and the danubian liassic cover sequence yields ft ages around 200 ma suggesting cooling of the rift flanks prior to the opening of the severin rift zircon and sphene from the getic and danubian basement units yield ft ages averaging 110 ma and indicating cooling under 240 c of the basement contemporaneous with or postdating thrusting apatite ft ages display a decreasing age trend from the hangingwall 65 ma to the footwall units 30 ma the age data and corresponding horizontal confined track length distributions suggest that exhumation of the nappe pile occurred in two stages the first is related to the late cretaceous nappe stacking and the second one to the final thrusting of the south carpathians onto the top of the moesian platform apatite ft ages along major brittle wrench faults indicate reheating above ca 120 c during fluid flow associated with fault re activation during oligocene and neogene times thus shear zone rocks experienced a higher temperature overprint during cenozoic time than rocks of the unaffected nappe pile temperatures of hydrothermal flow along these zones decreased below 100 c progressively starting with the late oligocene early miocene when the area began to override the moesian platform

tertiary tectonic evolution of the external south carpathians and the adjacent moesian platform romania depth interpreted seismic sections of the getic depression foredeep paleostress indicator data and analysis of outcrop to regional scale structures are integrated to derive the tectonic evolution of the south carpathians moesian platform area following late cretaceous and older orogenic phases the south carpathians moesian platform area underwent strike slip deformation with ne sw oriented compression and nw se tension in paleogene to early burdigalian times tensional deformation is recorded which led to the opening of wsw ene to e w trending extensional basins in the late burdigalian ne sw oriented contraction took over causing the oblique inversion of preexisting extensional structures during sarmatian times nw se and slightly younger n s trending compression caused the activation of mainly nw se dextral strike slip faults and in the frontal areas south directed thrusting the nw se direction of extension determined for paleogene to early burdigalian times is hardly compatible with presently accepted models of substantially continuous dextral wrenching between the intra carpathians units to the north of the south carpathians and the moesian platform to the south in contrast we have demonstrated dextral transpressive to transtensional movements within an e w trending corridor from the late burdigalian to late sarmatian which are compatible with available models

variscan vs alpine tectonothermal evolution of the southern carpathian orogen constraints from 40ar 39ar ages abstract 40 ar 39 ar hornblende and muscovite ages indicate that basement units exposed within all major alpine nappes of the southern carpathian orogen were penetratively deformed and metamorphosed during late variscan carboniferous tectonothermal events subsequent exhumation resulted in cooling from ca 500 c hornblende k ar retention temperature to ca 375 c muscovite k ar retention temperature between ca 320 and 295 ma late variscan exhumation of middle crustal levels is interpreted to have resulted from intracontinental contraction and regional uplift subsequent to variscan continental collision between gondwana derived tectonic elements e g africa and laurussia muscovite ages within mylonite zones suggest that late variscan shear zones were probably associated with a regional shear system that developed along the southern margins of laurussia alpine metamorphic effects within the southern carpathians are generally nonpenetrative and are only significant within narrow zones of retrogression that are interpreted to have formed during initial attenuation of variscan crust associated with formation of the jurassic severin rift

palaeogeography and geodynamic evolution of the gosau group of the northern calcareous alps late cretaceous eastern alps austria abstract the sedimentation of the late cretaceous gosau group of the northern calcareous alps records the complex geodynamic evolution of the northern part of the austroalpine microplate the tectonically controlled sedimentation and facies distribution were mainly governed by the oblique subduction of the pennic ligurian ocean below the austroalpine margin most of the gosau successions comprise two distinct sedimentary complexes the lower gosau subgroup upper turonian campanian is characterized by terrestrial to shallow marine facies associations alluvial fan and fan delta deposits shallow marine sandstones and sandy limestones and storm influenced nearshore and shelf deposits during the early santonian sea level highstand a great part of the northern calcareous alps was covered by a shallow shelf sea palaeotransport directions point to source areas situated both to the north and to the south of the northern calcareous alps the upper gosau subgroup upper santonian eocene comprises deep water hemipelagic and turbiditic deposits rapid subsidence into bathyal to abyssal depths started diachronously from the northwest santonian to the southeast maastrichtian after a short phase of deformation and erosion abyssal deposits in the northern parts of the northern calcareus alps and north directed palaeotransport indicate a tilting of the slope towards the north this subsidence pulse is attributed to an event of subcrustal tectonic erosion probably triggered by the subduction of a topographic high of the south penninic ocean the relationships of the gosau group of the austroalpine unit to late cretaceous deposits of the carpathians and southern alps are discussed in the framework of a plate tectonic model

late cretaceous carbon and oxygen isotope stratigraphy nannofossil events and paleoclimate fluctuations in the haţeg area sw romania abstract this study presents carbon and oxygen isotope fluctuations identified in marine red marlstones and claystones of the fizesti formation from the se ha eg area southern carpathians romania biostratigraphy based on calcareous nannoplankton allow the identification of nannofossil standard zones and subzones cc16 cc17 up to cc20 and respectively uc11c up to uc15b indicating that the investigated deposits are latest coniacian late early campanian in age throughout the studied succession 13c values fluctuate between 1 4 and 2 65 while 18o values are between 3 and 4 in the middle santonian within the uc12 calcareous nannofossil zone we found a slight positive carbon isotope excursion with values increasing by 0 3 up to a value of 2 44 which we assume to represent the regional expression of the horseshoe bay event originally recognized in the english chalk in the uppermost santonian just below the first occurrence of the crinoid marsupites testudinarius within the uc13 calcareous nannofossil zone we recorded a 13c increase from 2 38 up to 2 63 correlative with the hawks brow event firstly described in uk the most significant 13c increase identified by us up to 2 63 is coincident with the last occurrence of the crinoid marsupites testudinarius the santonian campanian boundary and represents the regional expression of the worldwide distributed santonian campanian boundary event the santonian campanian boundary is associated with a slight positive excursion for 18o in the lower part of the campanian stage 13c values progressively decrease to around 1 5 a decrease of the water surface temperature in the region is suggested for the lower part of the santonian an assumption based on the significant shift to less negative values of 18o and on the mixed tethyan and boreal character of the identified nannofloras from the santonian campanian boundary interval upwards the temperatures were rising leading to an arid and warm climate in the region this climate mode continued probably into the maastrichtian when the ha eg area became part of an island situated in the northern tethys realm

deepwater formation in the north pacific during the last glacial termination between approximately 17 500 and 15 000 years ago the atlantic meridional overturning circulation weakened substantially in response to meltwater discharges from disintegrating northern hemispheric glacial ice sheets the global effects of this reorganization of poleward heat flow in the north atlantic extended to antarctica and the north pacific here we present evidence from north pacific paleo surface proxy data a compilation of marine radiocarbon age ventilation records and global climate model simulations to suggest that during the early stages of the last glacial termination deep water extending to a depth of approximately 2500 to 3000 meters was formed in the north pacific a switch of deepwater formation between the north atlantic and the north pacific played a key role in regulating poleward oceanic heat transport during the last glacial termination

late cretaceous exhumation of the metamorphic gleinalm dome eastern alps kinematics cooling history and sedimentary response in a sinistral wrench corridor abstract the metamorphic gleinalm dome eastern alps was uplifted and exhumed within a releasing structure in a sinistral wrench corridor during the late cretaceous the dome is confined by a system of ductile shear zones including low angle normal faults and steep sinistral tear faults which define a large releasing structure with the metamorphic dome in its center the fabrics developed within all ductile shear zones record processes which were operating during decreasing temperatures from initial epidote amphibolite upper greenschist facies conditions with crystal plastic fabrics in quartz to temperatures below ca 300 c with predominantly cataclastic fabrics a cooling path based on 40ar 39ar amphibole 95 4 1 2 ma and muscovite ages 87 6 0 6 84 3 0 7 ma together with sphene zircon and apatite fission track data indicate cooling through ca 500 c at ca 94 ma to below ca 250 200 c at 65 ma subsidence of the adjacent late cretaceous kainach gosau basin occurred synchronously with cooling and uplift of the gleinalm dome internal depositional patterns record rapid subsidence at the time of cooling with internal synsedimentary block rotation above an intra crustal ductile normal fault the sinistral wrench corridor of the eastern alps developed by sinistral displacement of the austroalpine units against a relatively stable europe during the late cretaceous

garnet compositions in scottish and norwegian basement terrains a framework for interpretation of north sea sandstone provenance detrital garnets have proved to be useful discriminators of north sea sandstone provenance because they show a wide range of potential compositions and are relatively stable during burial diagenesis it has been less easy to use garnet data to provide a direct link between sediment and source because of the lack of a comprehensive database of garnet compositions in basement terrains forming the north sea hinterland this paper presents garnet compositional data from river sediments sourced from northern scotland and norway and demonstrates the presence of marked variations in garnet compositions from different regions related to fundamental differences in basement lithology the value of the river sediment database is demonstrated by comparing it with garnet compositions in paleocene sandstones from the north sea and more basins enabling the establishment of direct links between source and sediment paleocene sandstones in the gannet field area on the southwestern margin of the central north sea were derived from the dalradian of the grampian highlands those in the northern north sea were derived from the moine dalradian rocks of shetland and those along the more basin margin were derived from western norway by contrast paleocene sandstones in the nelson field central north sea and in the beryl embayment northern north sea have a garnet component that cannot be readily traced back to any basement terrain in either scotland or norway this component which was ultimately derived from granulite facies metasediments or charnockites is interpreted as being recycled from triassic sandstones which were themselves derived from an exotic source probably to the west of the british isles q 2004 elsevier ltd all rights reserved

age and significance of core complex formation in a very curved orogen evidence from fission track studies in the south carpathians romania abstract twenty four new zircon and apatite fission track ages from the getic and danubian nappes in the south carpathians are discussed in the light of a compilation of published fission track data a total of 101 fission track ages indicates that the getic nappes are generally characterized by cretaceous zircon and apatite fission track ages indicating cooling to near surface temperatures of these units immediately following late cretaceous orogeny the age distribution of the danubian nappes presently outcropping in the danubian window below the getic nappes depends on the position with respect to the cerna jiu fault eocene and oligocene zircon and apatite central ages from the part of the danubian core complex situated southeast of this fault monitor mid tertiary tectonic exhumation in the footwall of the getic detachment while zircon fission track data from northwest of this fault indicate that slow cooling started during the latest cretaceous the change from extension getic detachment to strike slip dominated tectonics along the curved cerna jiu fault allowed for further exhumation on the concave side of this strike slip fault while exhumation ceased on the convex side the available fission track data consistently indicate that the change to fast cooling associated with tectonic denudation by core complex formation did not occur before late eocene times i e long after the cessation of late cretaceous thrusting core complex formation in the danubian window is related to a larger scale scenario that is characterized by the nnw directed translation followed by a 90 clockwise rotation of the tisza dacia block due to roll back of the carpathian embayment this led to a complex pattern of strain partitioning within the tisza dacia block adjacent to the western tip of the rigid moesian platform our results suggest that the invasion of these southernmost parts of tisza dacia started before the late eocene i e significantly before the onset of miocene age rollback and associated extension in the pannonian basin

lithology and biostratigraphy of upper cretaceous marine deposits from the haţeg region romania palaeoenvironmental implications abstract this paper presents the lithological and biostratigraphical mainly based on calcareous nannofossils record of the marine sediments which crop out in the nw and se ha eg regions upper cretaceous marine deposition starts in these two regions in the early cenomanian both in the cc9 calcareous nannofossil zone and within uc1 uc2 biozones respectively in nw ha eg a hemipelagic sequence composed of red shales and marlstones followed by white marlstones probably associated with a deep water paleoenvironment marked the beginning of upper cretaceous marine sedimentation in the se marine deposition started with sandstones and calcarenites interlayered with actaeonella and ytruvia coquina indicating an infralittoral paleoenvironment from the cenomanian up to the coniacian the marine setting becomes progressively shallower in the two upper cretaceous marine depositional ha eg areas this change is marked by the occurrence of outer shelf deposits in the nw and inner shelf sediments up to infralittoral ones in the se these deposits are followed by lower santonian upper campanian turbidites in the nw and by lower santonian campanian pro parte red marlstones and upper campanian turbidites in the se the marine sedimentation ends in nw ha eg with distal turbidites late campanian in age placed in the cc22 calcareous nannofossil zone in the uc15d subzone respectively slightly above the first occurrence of the nannofossil uniplanarius trifidus towards the end of the campanian conglomerates and sandstones with actaeonella and ytruvia coquina yielding reworked nannofloras including late campanian taxa occur in se ha eg associated with the paroxysmal laramian tectonic phase continental deposition started probably within the campanian maastrichtian boundary interval both in the nw and se parts of the ha eg region during the late cretaceous interval different paleoenvironmental settings may be distinguished in the nw ha eg where a deep marine basin developed for most of the early cenomanian up to the late campanian interval and in the se ha eg characterised by an outer oscillating basin with an episodic shallow water deposition in the same interval despite the various backgrounds of the two regions some common regional events such as the early middle cenomanian and the early santonian early late campanian sea level highstand as well as the late cenomanian coniacian sea level lowstand were recognised in both investigated areas

orogen parallel extension in the southern carpathians a structural study including a kinematic analysis based on sense of shear criteria recorded in fault rocks is combined with fission track dating a two stage alpine tectonic evolution is proposed for the major tectonic units which constitute the southern carpathians of the parang mountains area upper cretaceous top to the sse nappe stacking was followed by wsw ene orogen parallel extension in the eocene top to the ene shearing in lower greenschist facies mylonites from the eastern part of the danubian window parang mountains is associated with a low angle detachment at the base of the brittlely deformed getic nappe the getic detachment below the dome shaped getic detachment east dipping at the eastern termination of the danubian window the danubian units were rapidly exhumed hence the eastern part of the danubian window represents a greenschist facies core complex as a working hypothesis it is proposed that this orogen parallel stretch was originally n s oriented and that it formed when the rhodopean fragment which includes the getic and supragetic nappes moved northward into an oceanic embayment past the western margin of moesia this eocene extension was part of a process of oroclinal bending in the area of the southern carpathians and their continuation into the balkan mountains extension was followed by about 50o clockwise rotation of the southern carpathians associated with dextral wrenching along the northern boundary of moesia and compression in the moldavides of the eastern carpathians 1998 elsevier science b v all rights reserved

palaeoceanography pacific and atlantic synchronized deep convection does not normally occur in the modern north pacific ocean but that may have changed during the last deglaciation sea ice and surface temperature reconstructions show that if so it was not associated with significant northward heat transport

the atlantic pacific seesaw abstract a global oceanic teleconnection of salinity meridional overturning circulation moc and climate of the north atlantic and north pacific is proposed simulations with a global climate model show that an extraction of freshwater from the pacific results not only in an increase of salinity there but also in a decrease of salinity in the atlantic as a result a pacific moc develops while the atlantic moc collapses without freshwater perturbation in the atlantic similarly an input of freshwater to the atlantic leads not only to a decrease of salinity there but also to an increase of salinity in the pacific the atlantic moc collapses whereas the pacific moc develops without freshwater perturbation in the pacific the mechanism behind this antiphase atlantic pacific relationship is the positive feedback between ocean circulation and salinity contrasts originally proposed by stommel to operate between low and high latitudes here the authors show that the same mechanism operates on the atlan

heavy mineral distributions of maastrichtian deposits from the haţeg basin south carpathians tectonic and palaeogeographic implications abstract this study represents the first extensive investigation of source areas of the maastrichtian continental deposits of the ha eg basin using heavy mineral associations the heavy mineral associations consist of garnet hematite magnetite ilmenite rutile staurolite kyanite epidote apatite titanite tourmaline and zircon the general pattern indicates different source areas with contrasting metamorphic grades for the northern and southern parts of the basin the sediments of the northern and central sectors of the basin show a high proportion of garnet staurolite and kyanite and a low proportion of epidote suggesting an amphibolite facies metamorphic source which is compatible with the lithology of the getic upper plate on which the basin formed the samples with abundant amphibolite facies heavy mineral components have high proportions of magnetic fe ti oxides with complex exsolution intergrowth features these oxides belong chiefly to the hematite ilmenite solid solution series and indicate a high grade metamorphic and or igneous source area in the south the heavy mineral spectra change to epidote rich evidence of exhumation and erosion of the greenschist metamorphic rocks of the danubian lower plate during updoming and core complex formation the study shows that for the northern and central parts of the basin the getic plate is the main source for the sediments during the maastrichtian time due to increasing relief in the hinterland and exhumation of the lower plate the danubian unit fed the basin as recorded in the sediments situated along sibisel and r ul b rbat valley

subsidence analysis and tectonic evolution of the external carpathian moesian platform region during neogene times abstract the miocene pliocene subsidence of the tectonic platforms in the romanian carpathians foreland is analysed using standard 1d backstripping techniques for individual wells combined in two regional sections and six contour maps the subsidence patterns were integrated together with previous paleostress and kinematic studies in order to derive the tertiary kinematics of the buried faults in the carpathians lower plate the study revealed accelerated subsidence during the early miocene in the western part of the moesian platform getic depression in direct relationship with the opening of a wsw ene trending extensional basin the largest subsidence recorded in the front of the carpathians took place during the late miocene due to final e ward emplacement of the thrust sheets the late miocene subsidence showed anomalous high values between the intramoesian and trotus faults as a result of the orogenic collision with the east european platform northward and acceleration of the subduction process in the se carpathians corner further pliocene subsidence continued only in the latter region the depocenter being shifted southward near the junction with the south carpathians foreland

deglacial subarctic pacific surface water hydrography and nutrient dynamics and links to north atlantic climate variability and atmospheric co2 the glacial to holocene evolution of subarctic pacific surface water stratification and silicic acid si dynamics is investigated based on new combined diatom oxygen 18odiat and silicon 30sidiat isotope records along with new biogenic opal subsurface foraminiferal 18o alkenone based sea surface temperature sea ice diatom and core logging data from the ne pacific our results suggest that 18odiat values are primarily influenced by changes in freshwater discharge from the cordilleran ice sheet cis while corresponding 30sidiat are primarily influenced by changes in si supply to surface waters our data indicate enhanced glacial to mid heinrich stadial 1 hs1 ne pacific surface water stratification generally limiting the si supply to surface waters however we suggest that an increase in si supply during early hs1 when surface waters were still stratified is linked to increased north pacific intermediate water formation the coincidence between fresh surface waters during hs1 and enhanced ice rafted debris sedimentation in the north atlantic indicates a close link between cis and laurentide ice sheet dynamics and a dominant atmospheric control on cis deglaciation the bolling allerod b a is characterized by destratification in the subarctic pacific and an increased supply of saline si rich waters to surface waters this change toward increased convection occurred prior to the bolling warming and is likely triggered by a switch to sea ice free conditions during late hs1 our results furthermore indicate a decreased efficiency of the biological pump during late hs1 and the b a possibly also the younger dryas suggesting that the subarctic pacific has then been a source region of atmospheric co2

sea surface temperatures in the subarctic northeast pacific reflect millennial scale climate oscillations during the last 16 kyrs changes of sea surface temperature sst in the subarctic ne pacific over the last 16 000 calendar years before present 16 kyr bp have been inferred from the study of c 37 alkenone unsaturation in a sediment core from the western canadian continental slope between 16 0 and 11 0 kyr three distinct cold phases 6 7 c interrupt two warmer periods 9 10 c within the 2 range of the radiocarbon based time control the observed sst oscillations correspond to the oldest dryas the bolling the older dryas the allerod and the younger dryas periods in the gisp2 18 o record these results represent the first high resolution marine paleotemperature estimates off the northern west coast of north america and imply that the climate of this region may be very strongly coupled to that of the north atlantic given the fast rates of sst change 1 c 40 80 yr such coupling must be controlled by atmospheric transmission of the climate signal

taphonomical and palaeoecological investigation of the late cretaceous maastrichtian tustea vertebrate assemblage romania haţeg basin insights into a unique dinosaur nesting locality abstract the tustea vertebrate locality at oltoane hill northwestern part of the ha eg basin romania has provided a rich and diverse assemblage of late cretaceous maastrichtian continental vertebrates more than 800 vertebrate fossils were recovered from this locality the isolated and associated remains represent 21 different taxa including amphibians turtles lizards snakes crocodyliforms pterosaurs dinosaurs and mammals the local assemblage is overwhelmingly dominated by dinosaurs with the rhabdodontid zalmoxes as the most abundant taxon the bonebeds that yielded this fossil material occur in a stacked series of mudstone calcrete units belonging to the middle member of the densus ciula formation the taphonomical investigations suggest that the tustea assemblage is made up of attritionally accumulated politaxic remains and that it is a parautochthonous assemblage with no evidence for significant bone transport or reworking according to the synthesis of all available field data two outstanding fossiliferous levels can be identified within the tustea locality where megaloolithus eggs and hadrosauroid hatchling material are preserved together recognized here as two superposed nesting grounds such co occurrence was considered controversial since there is a long standing and quasi general consensus that eggs of the megaloolithus oogenus were laid by titanosaurian sauropods we present several alternative scenarios to account for the co occurrence of telmatosaurus hatchling remains and megaloolithid eggs in the nesting horizons and explore these alternative hypotheses by weighing the arguments supporting or contradicting them the burden of evidence derived from our sedimentological taphonomical and palaeoecological investigations at tustea is still in favour of the autochthony of the hatchlings preserved within their own nesting grounds whereas there is no such support for a titanosaurian origin of the tu tea megaloolithid eggs

increased ventilation age of the deep northeast pacific ocean during the last deglaciation the amount of radiocarbon depleted carbon dioxide in the atmosphere rose dramatically during the last deglaciation estimates of the radiocarbon content of water at 2 7 km depth in the northeast pacific ocean over the past 24 000 years suggest that this water mass was not a significant source of this carbon

palaeomagnetism of the upper cretaceous sânpetru formation haţeg basin south carpathians abstract this paper reports on the palaeomagnetism of 10 localities from upper cretaceous sediments of the s npetru formation exposed in the ha eg basin south carpathians romania the s npetru formation is one of the best exposed latest cretaceous continental successions of eastern europe being famous for its unique assemblage of dinosaurs mammals and other vertebrates a total of 169 samples were collected from 66 strata through an 860 m thick section for most of the samples the remanences were soft and or noisy forcing us to reject 63 of the collection in the rest of the collection both polarities are observed and inclination only analysis indicates that pre tilting remanence is preserved for many samples these data along with published palaeomagnetic results from the ha eg basin pass a regional fold test the palaeomagnetic study has provided an acceptable magnetostratigraphy which shows that the studied part of the s npetru formation was deposited between the beginning of the chron 32n 1n and the end of chron 31n these first palaeomagnetic results obtained from the upper cretaceous sedimentary rocks from the south carpathians confirm the previous palaeomagnetic results obtained from magmatic rocks the subtropical palaeolatitude during late cretaceous and the large clockwise rotation during the tertiary

alpine polyphase tectono metamorphic evolution of the south carpathians a new overview abstract the main terrains involved in the cretaceous tertiary tectonism in the south carpathians segment of the european alpine orogen are the getic supragetic and danubian continental crust fragments separated by the severin oceanic crust floored basin during the early middle cretaceous times the danubian microplate acted initially as a foreland unit strongly involved in the south carpathians nappe stacking multistage folding thrusting events uplift erosion and extensional stages and the development of associated sedimentary basins characterize the south carpathians during cretaceous to tertiary convergence and collision events the main cretaceous tectogenetic events responsible for contraction and crustal thickening processes in the south carpathians are mid cretaceous austrian phase and latest cretaceous laramide or getic phase in age the architecture of the south carpathians suggests polyphase tectonic evolution and mountain building and includes from top to bottom the getic supragetic basement cover nappes the severin and arjana cover nappes and danubian basement cover nappes all tectonically overriding the moesian platform the severin nappe complex including obarsia and severin nappes with late jurassic early cretaceous ophiolites and turbidites is squeezed between the danubian and getic supragetic basement nappes as a result of successive thrusting of dismembered units during the inferred mid to late cretaceous subduction collision followed by tectonic inversion processes early cretaceous thick skinned tectonics was replaced by thin skinned tectonics in late cretaceous thus the former middle cretaceous austrian nappe stack and its albian lower senonian cover got incorporated in the intra senonian laramide getic stacking of the getic supragetic severin arjana nappes onto the danubian nappe duplex the two contraction events are separated by an extensional tectonic phase in the upper plate recorded by the intrusion of the banatitic magmas 84 73 ma the overthrusting of the entire south carpathian cretaceous nappe stack onto the fold thrust foredeep units and to the moesian platform took place in the late miocene intra sarmatian times and was followed by extensional events and sedimentary basin formation

large climate driven changes of oceanic oxygen concentrations during the last deglaciation during the last glacial termination the solubility of gases in the ocean decreased as ocean temperatures rose however marine sediments have not unanimously recorded ocean deoxygenation throughout this time some records show increasing oxygenation since the last glacial maximum particularly in the deep sea while many document abrupt oxygenation changes often associated with apparent changes in the formation rate of north atlantic deep water here we present a global compilation of marine sediment proxy records that reveals remarkable coherency between regional oxygenation changes throughout deglaciation the upper ocean generally became less oxygenated but this general trend included pauses and even reversals reflecting changes in nutrient supply respiration rates and ventilation the most pronounced deoxygenation episode in the upper ocean occurred midway through the deglaciation associated with a reinvigoration of north atlantic deep water formation at this time the upper indo pacific ocean was less oxygenated than today meanwhile the bulk of the deep ocean became more oxygenated over the deglaciation reflecting a transfer of respired carbon to the atmosphere the observed divergence from a simple solubility control emphasizes the degree to which oxygen consumption patterns can be altered by changes in ocean circulation and marine ecosystems

metamorphic evolution of a very low to low grade metamorphic core complex danubian window in the south carpathians the danubian window characterized by diagenetic to low greenschist facies conditions at a high thermal gradient is evidently of great interest for methodological studies because high metamorphic thermal gradient conditions during low grade metamorphism have received little attention so far the general increase in metamorphic grade from sw to ne in the danubian window is indicated by mineral parageneses studies as well as by illite kubler index ki measurements and organic matter reflectance omr for the first time this study distinguishes between metamorphic conditions related to jurassic ocean floor cretaceous nappe stacking post collisional accommodation and syn kinematic getic detachment metamorphism and cooling after oligocene exhumation the occurrence of the prehnite pumpellyite facies in the severin cosustea units in the southeastern area is the result of cretaceous metamorphism remnants of ocean floor metamorphism prevailed the highest pressure is constrained by the upper stability limit of prehnite to be at around 4 0 kbar the danubian units situated within the diagenetic zone were not below 200 8c due to epidote formation the ki omr and mineral data indicate diagenetic conditions assuming temperatures between 200 and 250 8c pressures between 1 8 and 2 6 kbar were calculated using kinetic and numerical maturity models orogenic collisional cretaceous peak pressure conditions of 4 0 1 0 kbar are found in the danubian nappes not altered by a subsequent syn detachment metamorphic overprint highest temperatures in chloritoid schists and epidote hornblende bearing mylonites have been inferred for samples from the northern border of the danubian window between 300 and 400 8c along a synto post detachment retrograde pressure path post dating the chloritoid formation the occurrence of clinozoisite chlorite quartz suggests temperatures 300 8c in the northwest while the association andalusite quartz and biotite muscovite indicates temperatures between 370 and 400 8c at 3 5 kbar in the northeast it is demonstrated that the slope of the regression lines between ki and omr data gives valuable qualitative information about the relative magnitudes of p and t the slope of the regression line for the danubian window samples indicates normal heat flow conditions during nappe stacking and hyperthermal conditions during the formation of the getic detachment high thermal gradient conditions can easily be explained by partly isothermal decompression during the getic detachment event the elevation of the geotherm being caused by crustal thinning and rapid exhumation of the danubian units probably also a higher heat flux prevailed at the end of the getic detachment at a time when the retrograde chloritoid decomposition reactions took place documenting late stage ht greenschist facies metamorphism from siegesmund s fugenschuh b froitzheim n eds tectonic aspects of the alpine dinaridecarpathian system geological society london special publications 298 281 315 doi 10 1144 sp298 14 0305 8719 08 15 00 the geological society of london 2008 location of the study area and

titanian clinohumite and geikielite in marbles from the bergell contact aureole the assemblage titanian clinohumite forsterite spinel calcite is widespread in marbles from the eastern bergell contact aureole switzerland italy the bergell titanian clinohumites vary considerably in composition tio2 0 19 to 2 05 wt f 2 2 to 3 4 wt electron microprobe analyses show that the titanian clinohumites contain less than detectable amounts of co cu ni zn al cr and cl no trace of ferric iron could be detected by moessbauer spectroscopy moreover the moessbauer spectra indicate that fe2 occurs only in one of the five octahedral positions in the crystal structure of the studied titanian clinohumite under the conditions of the contact metamorphism 600 650 c 3 kb total pressure the compositional variation along the exchange vector tio2m 1 oh f 2 takes place at constantxoh which is fixed by the pore fluid titanian clinohumite sometimes contains geikielite inclusions which strongly fractionate fe and mn relative to titanian clinohumite the geikielites from the bergell marbles are poor in cr2o3 fe2o3 and mno and thus different from those found in carbonatites kimberlites and serpentinized ultramafic rocks

bioerosion on vertebrate remains from the upper cretaceous of the haţeg basin romania and its taphonomic implications abstract bioerosion on fossil bones offers significant insights into both trophic relationships of ancient ecosystems and vertebrate taphonomy here we report six distinct trace fossil categories identified on isolated turtle crocodyliform and dinosaur remains from the upper cretaceous sinpetru formation of the ha eg basin romania for which five different probable tracemakers are identified 1 termites 2 dermestid beetles 3 multituberculate mammals 4 ziphodont theropod dinosaurs or crocodyliforms and 5 plants this extraordinary diversity of bioerosional trace fossils on vertebrate remains reveals insect vertebrate as well as vertebrate vertebrate interactions previously undocumented in the continental uppermost cretaceous of romania the association between different traces especially since many of these are superimposed on top of each other allows the reconstruction of the detailed taphonomic history of the specimens indicating four different taphonomic pathways the vertebrate remains with trace fossils described here were most likely exposed to post mortem biotic interactions for a prolonged time period before they were transported and or trampled and finally buried in the palaeoenvironmental context of a heterogeneous braided river system with low lying wetlands and more elevated drylands the death of the vertebrates as well as the scavenging likely occurred on the drylands

a link of china warming hiatus with the winter sea ice loss in barents kara seas since the late 1990s the global warming has ground to a halt which has sparked a rising interest among the climate scientists the hiatus is not only observed in the globally averaged surface air temperature sat but also in the china winter temperature trend which turns from warming during 1979 1997 to cooling during 1998 2013 however the reasons and the relevant mechanisms of the warming hiatus are far from being understood arctic sea ice asi one of the tipping points of the earth system change has contributed to the dramatic climate change it is found that the asi over the barents kara seas in the warming hiatus period 1998 2013 has declined about three times faster than that in the previous continuing warming period 1979 1997 the observational analysis and the wave ray trajectories suggest that for the hiatus period the asi over the barents kara seas explains 61 4 of the decreasing sat trend and 14 4 of the interannual sat variation in china the possible dynamical process is as follows the anomalous asi loss associated with the significant warming in barents kara seas can excite a downstream teleconnection wave train pattern over the eurasia continent the significant easterly winds in the subpolar region slacken the polar front jet while the anomalous westerly winds over the tibetan plateau reinforce the east asian subtropical jet as a result the concurrent out of phase variations in the intensity of the jets lead to the cold flow moving southward from the arctic and converging in china the northwest southeast tilted dipole pattern of the height centers over eurasia accompanied with the weakened polar front jet usually favors the persistence of ural blocking ub furthermore in the lower level the anomalous high pressure belt over the northern eurasian continent can help cold northeasterly winds blow from the russian far east to china and bring about the cold winters thus the accelerated melting of asi can exert a profound influence on china warming hiatus in recent two decades

sea surface temperature variability and sea ice extent in the subarctic northwest pacific during the past 15 000 years past changes in north pacific sea surface temperatures and sea ice conditions are proposed to play a crucial role in deglacial climate development and ocean circulation but are less well known than from the north atlantic here we present new alkenone based sea surface temperature records from the subarctic northwest pacific and its marginal seas bering sea and sea of okhotsk for the time interval of the last 15 kyr indicating millennial scale sea surface temperature fluctuations similar to short term deglacial climate oscillations known from greenland ice core records past changes in sea ice distribution are derived from relative percentage of specific diatom groups and qualitative assessment of the ip25 biomarker related to sea ice diatoms the deglacial variability in sea ice extent matches the sea surface temperature fluctuations these fluctuations suggest a linkage to deglacial variations in atlantic meridional overturning circulation and a close atmospheric coupling between the north pacific and north atlantic during the holocene the subarctic north pacific is marked by complex sea surface temperature trends which do not support the hypothesis of a holocene seesaw in temperature development between the north atlantic and the north pacific key points millennial scale changes in sst in the north pacific during the last 15 kyr changes in sea ice extent suggest a close coupling to sst fluctuations middle to late holocene ssts show no clear sst trend in the north pacific