warming of global abyssal and deep southern ocean waters between the 1990s and 2000s contributions to global heat and sea level rise budgets abyssalglobalanddeepsouthern oceantemperature trendsarequantifiedbetweenthe1990sand2000sto assesstheroleofrecentwarmingoftheseregionsin globalheatandsealevelbudgets theauthors1 compute warming rates with uncertainties along 28 full depth high quality hydrographic sections that have been occupied two or more times between 1980 and 2010 2 divide the global ocean into 32 basins defined by the topography and climatological ocean bottom temperatures and then 3 estimate temperature trends in the 24 sampled basins the three southernmost basins show a strong statistically significant abyssal warming trend with that warming signal weakening to the north in the central pacific western atlantic and eastern indian oceans eastern atlantic and western indian ocean basins show statistically insignificant abyssal cooling trends excepting the arctic ocean and nordic seas the rate of abyssal below 4000 m global ocean heat content change in the 1990s and 2000s is equivalent to a heat flux of 0 027 60 009 w m 22 applied over the entire surface of the earth deep 1000 4000 m warming south of the subantarctic front of the antarctic circumpolar current adds 0 068 60 062 w m 22 the abyssal warming produces a 0 053 60 017 mm yr 21 increase in global average sea level and the deep warming south of the subantarctic front adds another 0 093 60 081 mm yr 21 thus warmingin theseregions ventilatedprimarilyby antarcticbottomwater accounts for a statistically significant fraction of the present global energy and sea level budgets

residence of ree y th and u in granites and crustal protoliths implications for the chemistry of crustal melts a systematic study with laser ablation icp ms scanning electron microscopy and electron microprobe revealed that 70 95 wt of ree except eu y th and u in granite rocks and crustal protoliths reside within reeythu rich accessories whose nature composition and associations change with the rock aluminosity the accessory assemblage of peraluminous granites migmatites and high grade rocks is composed of monazite xenotime in low ca varieties apatite zircon thorthosilicate uraninite and betafite pyrochlore metaluminous granites have allanite sphene apatite zircon monazite and thorthosilicaie peralkaline granites have aeschinite fergusonite samarskite bastnaesite fluocerite allanite sphene zircon monazite xenotime and th orthosilicate granulite grade garnets are enriched in nd and sm by no less than one order of magnitude with respect to amphibolite grade garnets granulitegrade feldspars are also enriched in lree with respect to amphibolite grade feldspars accessories cause non henrian behaviour of ree y th and u during melt solid partitioning because elevated fractions of monazite xenotime and zircon in common migmatites are included within major minerals their behaviour during anatexis is controlled by that of their host settling curves calculated for a convecting magma show that accessories are too small to settle appreciably being separated from the melt as inclusions within larger minerals biotite has the greatest tendency to include accessories thereby indirectly controlling the geochemistry of ree y th and u we conclude that ree y th and u are unsuitable for petrogenetical modelling of granitoids through equilibrium based trace element fractionation equations

mixing driven mean flows and submesoscale eddies over mid ocean ridge flanks and fracture zone canyons abstractto close the abyssal overturning circulation dense bottom water has to become lighter by mixing with lighter water above this diapycnal mixing is strongly enhanced over rough topography i

water geochemistry controlled by carbonate dissolution a study of the river waters draining karst dominated terrain guizhou province china concentrations of major ions and sr and sr isotopic compositions of two major river systems wujiang river and yuanjiang river in karst dominated regions and during winter were measured the rivers and their tributaries have high total dissolved solid concentrations with tz ranging from 2 1 to 6 3 meq l which are significantly higher than that of the global river average calcium and hco3 followed by mg2 and so42 dominate the chemical composition of major ions in the river waters both na k and cl si account for 5 10 of the cations and anions respectively the waters of the wujiang river have high sr2 concentrations and lower 87sr 86sr ratios 0 7077 0 7110 while those of the qingshuijiang river one of two major tributaries of the yuanjiang river system show higher sr isotopic ratios 0 7090 0 7145 and low sr concentrations the lithology and geography of the river basins largely control the chemical and isotopic compositions of these rivers analyses of the stoichiometry of the river waters show that the water chemistry is controlled by carbonate dissolution by both carbonic and sulfuric acid especially of the wujiang river and suggest an origin of sulfate mainly from atmospheric input because of coal combustion and or oxidation of sulfide minerals in the catchments we identify three main weathering sources limestone dolomite and silicates chemical and sr isotopic composition of wujiang river waters are characterized mainly by limestone weathering while those of the qingshuijiang river waters mainly by dolomite and silicate weathering chemical weathering rates of carbonate and silicate are estimated and the results indicate that the chemical weathering rates of carbonate in the catchments are remarkably high significantly higher than most large rivers it is considered that presence of sulfuric acid in the rock weathering overuse of land and deterioration of vegetation are most likely the key factors responsible for the high weathering rates of carbonate in the catchments

the dissipation of kinetic energy in the lofoten basin eddy abstractocean microstructure current and hydrography observations from june 2016 are used to characterize the turbulence structure of the lofoten basin eddy lbe a long lived anticyclone in the

transformation and upwelling of bottom water in fracture zone valleys abstractclosing the overturning circulation of bottom water requires abyssal transformation to lighter densities and upwelling where and how buoyancy is gained and water is transported upward rema

experimental determination of ree distributions between monazite and xenotime potential for temperature calibrated geochronology solid solutions of the ree y orthophosphates monazite and xenotime were synthesized hydrothermally between 300 c and 800 c at 2 and 5 kbar using ree y oxides and h3po4 as starting materials the ree bulk composition was similar to those found in metapelitic rocks all experiments produced two solid phases monoclinic monazite and tetragonal xenotime in volumetric ratios similar to relative abundances in metapelites ree concentrations of coexisting monazite xenotime pairs were determined by emp analysis and ree distribution coefficients dree xreemonazite xreexenotime were derived for the entire ree y suite values of dree depend strongly on ionic radii of the rees and on temperature the log dree vs ionic radius curve shows a nearly linear decrease from la to lu and comprises almost five orders of magnitude from dla 102 5 to dlu 10 2 between 450 and 800 c most dree values vary continuously by a factor of about 2 to 3 dnd decreases from 48 to 16 and dsm from 9 to 5 dtb increases from about 0 2 to about 0 4 ddy from 0 1 to 0 2 and dy from 0 06 to 0 12 along this temperature range experimentally determined values of dree are in close agreement with those derived from natural monazite xenotime pairs equilibrated between 400 and 700 c ree partitioning between monazite and xenotime is appropriate for geothermometry the most useful application is that equilibrium and disequilibrium partitioning of ree in metamorphic rocks are easily recognized in the case of equilibrium distributions u pb chronometry of single monazites or xenotimes provides a direct link to their growth conditions and information on temperature time paths equilibrium distributions of sm and nd expressed in molar fractions result in kd xsmmonazitexndxenotime xsmxenotimexndmonazite 0 2 to 0 3 from 600 to 800 c and sm nd chronometry should provide reasonable two mineral isochrons for such monazite xenotime pairs

generation of internal waves by eddies impinging on the western boundary of the north atlantic abstractdespite the major role played by mesoscale eddies in redistributing the energy of the large scale circulation our understanding of their dissipation is still incomplete this study investigates the generation of internal waves by decaying eddies in the north atlantic western boundary the eddy presence and decay are measured from the altimetric surface relative vorticity associated with an array of full depth current meters extending 100 km offshore at 26 5 n in addition internal waves are analyzed over a topographic rise from 2 yr high frequency measurements of an acoustic doppler current profiler adcp which is located 13 km offshore in 600 m deep water despite an apparent polarity independence of the eddy decay observed from altimetric data the flow in the deepest 100 m is enhanced for anticyclones 25 2 cm s 1 compared with cyclones 4 7 cm s 1 accordingly the internal wave field is sensitive to this polarity dependent deep velocity this is apparent from the eddy modulated enhanc

alteration and breakdown of xenotime y and monazite ce in granitic rocks of the western carpathians slovakia abstract in the granitic rocks of the western carpathians xenotime y occurs both as a late stage magmatic mineral and as a secondary post magmatic phase magmatic xenotime occurs with monazite and displays minor compositional zonation involving si th and u the source of elements for the formation of secondary xenotime y in the granitic rocks results from leaching of p and y ree mainly from zircon and apatite both xenotime y and monazite ce are unstable during fluid activated overprinting low temperature alteration of monazite in s type granites leads to the formation of apatite enriched in the britholite component but low to medium grades of metamorphism result in the formation of apatite and lree enriched epidote partly allanite as a corona enclosing the monazite ce core xenotime y shows a similar alteration pattern but with different ree distributions within the products at greenschist amphibolite facies rims of secondary y rich apatite and y rich epidote form around xenotime y in low ca granites however apatite is missing from this alteration assemblage as xenotime y breaks down directly to y enriched epidote the relative mobilities of the heavy and light ree are different during breakdown of monazite and xenotime the fluid responsible for the breakdown of monazite and xenotime contains elements released from alteration of anorthite ca and biotite si al and f

spatial variability of turbulent mixing in the abyssal ocean ocean microstructure data show that turbulent mixing in the deep brazil basin of the south atlantic ocean is weak at all depths above smooth abyssal plains and the south american continental rise the diapycnal diffusivity there was estimated to be less than or approximately equal to 0 1 x 10 4 meters squared per second in contrast mixing rates are large throughout the water column above the rough mid atlantic ridge and the diffusivity deduced for the bottom most 150 meters exceeds 5 x 10 4 meters squared per second such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry

electron microprobe dating of monazites from western carpathian basement granitoids plutonic evidence for an important permian rifting event subsequent to variscan crustal anatexis accessory monazites from 35 granitoid samples from the western carpathian basement have been analysed with the electron microprobe in an attempt to broadly constrain their formation ages on the basis of their th u and pb contents the sample set includes representative granite types from the tatric veporic and gemeric tectonic units in most cases lower carboniferous variscan ages have been obtained however a much younger mid permian age has been recorded for the specialised s type granites of the gemeric unit and several small a and s type granite bodies in the veporic unit and the southern tatric unit this distinct permian plutonic activity in the southern part of the western carpathians is an important although previously little considered geological feature it appears to be not related to the variscan orogeny and is interpreted here to reflect the onset of the alpine orogenic cycle with magma generation in response to continental rifting the voluminous carboniferous granitoid bodies in the tatric and veporic units comprise s and i type variants which document crustal anatexis accompanying the collapse of a compressional variscan orogen sector the variscan magmas were most likely produced through the remelting of a subducted precambrian volcanic arc type crust which included both igneous and sedimentary reworked volcanic arc material although the 2 errors of the applied dating method are quite large and typically 10 20 ma for single samples it would appear from the data that the variscan s type granitoids 333 367 ma are systematically older than the variscan i type granitoids 308 345 ma this feature is interpreted in terms of a prograde temperature evolution in the deeper parts of the post collisional variscan crust in accordance with recently published zircon ages this study shows that the western carpathian basement must be viewed as a distinct eastern tectonomagmatic province in the variscan collision zone where the post collisional crustal melting processes occurred 20 ma earlier than in the central sector south bohemian batholith hohe tauern batholith

temporal characteristics of abyssal finescale motions above rough bathymetry current meter data from a two year mooring within a fracture zone on the western flank of the midatlantic ridge in the south atlantic ocean are reported the mooring deployed in conjunction with the brazil basin tracer release experiment was placed in the general area where enhanced diapycnal mixing had previously been inferred the current meter data characterize the velocity temperature shear and temperature gradient variability as a function of frequency energetic velocities and shears were observed at the mooring at a variety of frequencies in addition to semidiurnal flows a significant amount of shear variance derived from near inertial motions as has been seen in a recent numerical modeling study of tidal frequency internal wave radiation and wave wave interaction at times a fortnightly modulation of the total superinertial shear variance was indicated in the data but this signal did not dominate the records wave ray tracing indicates that the deeper current meters may have been placed in a shadow zone for locally generated internal tides at shallower levels it is suggested that dispersion wave wave interaction and wave breaking effectively obscured the sources of the finescale energy average diapycnal diffusivity estimates inferred from a richardson number based parameterization and from observations of temperature inversions at 4648 m were of the same order of magnitude as those derived from turbulent dissipation estimates and from the rate of diapycnal tracer dispersion the mooring data thus add additional support to the idea that energetic finescale motions above rough bathymetry support enhanced turbulent diapycnal mixing in these regions

turbulent mixing in a deep fracture zone on the mid atlantic ridge abstractmidocean ridge fracture zones channel bottom waters in the eastern brazil basin in regions of intensified deep mixing the mechanisms responsible for the deep turbulent mixing inside the numerous midocean fracture zones whether affected by the local or the nonlocal canyon topography are still subject to debate to discriminate those mechanisms and to discern the canyon mean flow two moorings sampled a deep canyon over and away from a sill contraction a 2 layer exchange flow accelerated at the sill transports 0 04 0 10 sv 1 sv 106 m3 s 1 up canyon in the deep layer at the sill the dissipation rate of turbulent kinetic energy e increases as measured from microstructure profilers and as inferred from a parameterization of vertical kinetic energy cross sill density and microstructure transects reveal an overflow potentially hydraulically controlled and modulated by fortnightly tides during spring to neap tides e varies from o 10 9 to o 10 10 w kg 1 below 3500 m around the 2 layer inte

boundary mixing and topographic blocking on the mid atlantic ridge in the south atlantic abstract it is commonly observed in hydrographic sections crossing midocean ridges that the isopycnals on the ridge flanks slope downward toward the crests although the observed vertical scales of isopycnal dipping are not consistent with steady diffusive boundary layers on slopes the cross flank density gradients can nevertheless be caused by diapycnal mixing acting on timescales of several years the corresponding pressure gradients are usually inferred to be associated with cyclonic along flank flows recent observations of southward flow along the highly corrugated western flank of the mid atlantic ridge near 20 s are inconsistent with this conceptual picture however data from seven zonal cross ridge sections and from four meridional along ridge sections were used to analyze the hydrography on the flanks of the mid atlantic ridge between 2 n and 30 s the majority of the hydrographic stations were occupied over deep cross flank canyons which extend over a total length of 90 000 km in the tropica

monazite xenotime miscibility gap thermometry i an empirical calibration rare earth element ree and yttrium concentrations of coexisting monazite and xenotime were determined from a suite of seven metapelites from the variscan fold belt in ne bavaria germany the metapelites include a continuous prograde mainly low p 3 5 kbar metamorphic profile from greenschist c 400 c to lower granulite facies conditions c 700 c the lree la sm are incorporated preferentially in monoclinic monazite reo9 polyhedron whereas the hree plus y are concentrated in tetragonal xenotime reo8 polyhedron the major element concentrations of both phases in all rocks are very similar and do not depend on metamorphic grade monazite consists mainly of la ce and nd la0 20 0 23 ce0 41 0 45 nd0 15 0 18 po4 all other elements are below 6 mol likewise xenotime consists mainly of ypo4 with some dy and gd solid solutions y0 76 0 80 dy0 05 0 07 gd0 04 0 06 in contrast the minor hree concentrations in monazite increase strongly with increasing metamorphic grade y dy and gd increase by a factor of 3 5 from greenschist to granulite facies rocks monazite crystals often show zonation with cores low in hree and rims high in hree that is interpreted as growth zonation attained during prograde metamorphism similarly sm and nd in xenotimes increase by a factor of 3 4 with increasing metamorphic grade prograde zonation in single crystals of xenotime was not observed the xhree y in monazite and xlree in xenotime of the seven rocks define two limbs along the strongly asymmetric miscibility gap from c 400 c to 700 c the empirical calibration of the monazite miscibility gap limb coexisting with xenotime is appropriate for geothermometry due to its contents of u and th monazite has often been used for u pb age determination the combination of our empirical thermometer on prograde zoned monazite along with possible age determination of zoned single crystals may provide information about prograde branches of temperature time paths

dehydration melting and devolatilization during exhumation of high grade metapelites the tatra mountains western carpathians partial melting and retrogression related to variscan tectonic exhumation have been recognized in the high grade metapelites of the tatra mountains western carpathians staurolite and kyanite relics document an early stage of the prograde metamorphism at c 600 c and 9 10 kbar an increase in temperature to 730 c at 11 12 kbar resulted in partial melting and incipient migmatization in the stability field of kyanite further heating at decreasing pressure during the earliest stage of exhumation led to the dehydration melting of muscovite and biotite at 750 800 c and 6 10 kbar producing garnet bearing granite as leucosomes in migmatite subsequent cooling is documented by garnet resorption by biotite and sillimanite a reversal of the prograde biotite dehydration melting reaction this was followed by nearly isothermal decompression to c 4 5 kbar producing cordierite and some melt due to biotite decomposition later nearly isobaric cooling led to cordierite pinitization and formation of orthoamphibole chlorite and carbonates densities of primary monophase co2 n2 inclusions 0 69 1 06 g cm 3 from the migmatite leucosome are consistent with the near peak and retrograde conditions highly varying n2 contents 5 30 mol are thought to result from the nitrogen uptake in retrograde k bearing minerals or dilution by co2 liberated during interaction of melt derived water with metapelite graphite the relatively high nitrogen content not observed until now in migmatites could have been inherited from the high pressure metamorphism stage it is assumed that the water absent composition of fluid inclusions is not representative of the bulk water content xh2o 0 7 which was masked by mechanical separation of the co2 and h2o dominated immiscible phases and or by post entrapment modifications of the fluid inclusions decompression and the final stage of exhumation were accomplished by top to the south thrusting as well as west east orogen parallel extension they were most probably related to regional uplift and gravitational collapse of thermally weakened variscan crust

mixing associated with sills in a canyon on the midocean ridge flank to close the global overturning circulation the production and sinking of dense water at high latitudes must be balanced elsewhere by buoyancy gain and upward vertical motion hydrographic and microstructure observations from the brazil basin in the south atlantic ocean indicate that most of the abyssal mixing there takes place on the topographically rough flank of the midocean ridge in previous studies it has been suggested that the high level of abyssal mixing observed on the ridge flank is primarily caused by breaking internal waves forced by tidal currents here the results from a detailed analysis of velocity hydrographic and microstructure data from a ridge flank canyon are presented two year long current meter records indicate that within the canyon there is a significant along axial mean flow down the density gradient toward the ridge crest five hundred meters above the canyon floor the kinetic energy in the subinertial band exceeds that associated with the semidiurnal tides by approximately a factor of 2 the mean dissipation of kinetic energy inside the canyon exceeds that above the ridge flank topography by approximately a factor of 5 the largest dissipation values were observed downstream of a narrow 1000 m high sill that extends across the full width of the canyon along the entire canyon there is a strong association between the presence of sills and along axial density gradients while there is no similar association between the presence of depressions and density gradients together these observations suggest that sill related mixing contributes at least as much to the diapycnal buoyancy flux in the canyon as tidally forced internal wave breaking which is not expected to be associated preferentially with sills while only 15 of the interfacial area between antarctic bottom water and north atlantic deep water in the brazil basin lie inside canyons the available data suggest that approximately one half of the diapycnal buoyancy fluxes take place there in comparison the region above the ridge flank topography accounts for about one third of the buoyancy fluxes the apparent importance of sill related processes for mixing in ridge flank canyons is therefore of global significance especially considering that such canyons occur on average every 50 km along 2 3 of the global midocean ridge system and that sills partially block the canyon axes every few tens of kilometers

model studies of near inertial waves in flow over the oregon continental shelf abstract two dimensional primitive equation model studies of wind forced flow over a continental shelf show that under upwelling conditions high levels of near inertial wave energy are found in the interior over the shelf the regions of elevated wave energy with maximum wave amplitudes of around 0 2 m s 1 persist for up to two weeks and have spatial scales of 20 40 m vertically and 5 20 km horizontally relatively high dissipation levels are associated with these concentrations of wave energy when forced with downwelling favorable winds model results show very little subsurface inertial energy on the shelf a comparison of inertial wave propagation using the primitive equation model and a linearized version of the model demonstrates strong dependence on the background flow field the behavior of inertial waves using the linearized model is completely different very little subsurface inertial energy is seen on the shelf in either upwelling or downwelling conditions except where the bottom slope

metamorphic evolution and fluid composition of garnet clinopyroxene amphibolites from the tatra mountains western carpathians relics suggesting an early high pressure eclogite facies stage have been identified in the garnet and clinopyroxene bearing amphibolites of the tatra mountains in the variscan basement of the western carpathians slovakia in these rocks primary omphacite cpx i has been wholly converted to symplectites of diopside cpx ii and plagioclase apart from minor inclusions in the garnet cores amphibole and plagioclase are secondary minerals formed in the kelyphitic rims between garnet and clinopyroxene several generations of amphibole pargasite hornblende cummingtonite actinolite are evidence of a transformation down to greenschist facies conditions thermobarometric calculations from mineral inclusions in the garnet cores yield 670 700 c and 10 15 kbar recording the initial path from upper amphibolite to eclogite facies conditions the attainment of the eclogite facies stability field is inferred from the composition of a reconstructed omphacite jd36 implying a minimum peak pressure of 15 16 kbar conditions of around 650 c and 8 10 kbar record the post eclogite breakdown and partial re equilibration in the amphibolite facies region the earliest fluid inclusions contain high density nitrogen dominated water absent fluid younger are polyphase brines and two phase h2o n2 ch4 inclusions with signs of heterogeneous entrapment of coexisting gas rich and water rich immiscible phases pure nitrogen 0 5 mol ch4 is considered to have been the major component during the high pressure metamorphism in contrast the later aqueous inclusions are interpreted to represent retrogression related fluids the brines have originated by leaching and re entrapment of saline melt inclusions observed in tonalitic trondhjemitic layers of the amphibolite enclosing the eclogitic relics a similar mechanism is assumed for the origin of the h2o n2 ch4 inclusions these represent relics of the primary eclogite facies related n2 inclusions re equilibrated and re entrapped during retrogression under increasing water activity a possible source of n2 and cl rich fluids was primary amphibole which decomposed during the prograde metamorphism from the amphibolite to the eclogite facies the metamorphic pt path is generally clockwise reflecting a steep increase in pressure and temperature during burial followed by decompression and cooling the retrograded eclogites occur in boudins within an allochthonous unit of an inverted metamorphic sequence their exhumation was facilitated by tectonic transport along a ductile shear zone during the variscan orogeny

evidence for enhanced mixing over rough topography in the abyssal ocean the overturning circulation of the ocean plays an important role in modulating the earth s climate but whereas the mechanisms for the vertical transport of water into the deep ocean deep water formation at high latitudes and horizontal transport in ocean currents have been largely identified it is not clear how the compensating vertical transport of water from the depths to the surface is accomplished turbulent mixing across surfaces of constant density is the only viable mechanism for reducing the density of the water and enabling it to rise however measurements of the internal wave field the main source of energy for mixing and of turbulent dissipation rates have typically implied diffusivities across surfaces of equal density of only approximately 0 1 cm2 s 1 too small to account for the return flow here we report measurements of tracer dispersion and turbulent energy dissipation in the brazil basin that reveal diffusivities of 2 4 cm2 s 1 at a depth of 500 m above abyssal hills on the flank of the mid atlantic ridge and approximately 10 cm2 s 1 nearer the bottom this amount of mixing probably driven by breaking internal waves that are generated by tidal currents flowing over the rough bathymetry may be large enough to close the buoyancy budget for the brazil basin and suggests a mechanism for closing the global overturning circulation

buoyancy forcing by turbulence above rough topography in the abyssal brazil basin abstract observations of turbulent dissipation above rough bathymetry in the abyssal brazil basin are presented relative to regions with smooth bathymetry dissipation is markedly enhanced above rough topography of the mid atlantic ridge with levels above bathymetric slopes exceeding levels observed over crests and canyon floors furthermore mixing levels in rough areas are modulated by the spring neap tidal cycle internal waves generated by barotropic tidal flow over topography are the likely mechanism for supplying the energy needed to support the observed turbulent dissipation a model of the spatial and temporal patterns in the turbulent dissipation rate is used to constrain the diapycnal advection in an inverse calculation for the circulation in an area of rough bathymetry this inverse model uses both beta spiral and integrated forms of the advective budgets for heat mass and vorticity and contains sufficient information to resolve the full three dimensional flow the inverse model solution re

crystal chemistry of the monazite and xenotime structures monazite and xenotime the re p04 dimorphs are the most ubiquitous rare earth re minerals yet accurate structure studies of the natural phases have not been reported here we report the results of high precision structure studies of both the natural phases and the synthetic re p04 phases for all individual stable rare earth elements monazite is monoclinic p2 n and xenotime is isostructural with zircon space group 14 amd both atomic arrangements are based on 001 chains of intervening phosphate tetrahedra and re polyhedra with a reogpolyhedron in xenotime that accommodates the heavy lanthanides tb lu in the synthetic phases and a re09 polyhedron in monazite that preferentially incorporates the larger light rare earth elements la gd as the structure transforms from xenotime to monazite the crystallographic properties are comparable along the 00i chains with structural adjustments to the different sizes of re atoms occurring principally in 00i there are distinct similarities between the structures that are evident when their atomic arrangements are projected down 001 in that projection the chains exist in 100 planes with two planes per unit cell in monazite the planes are offset by 2 2 a along 010 relative to those in xenotime in order to accommodate the larger light re atoms the shift of the planes in monazite allows the re atom in that phase to bond to an additional 02 atom to complete the re09 polyhedron

radiation and dissipation of internal waves generated by geostrophic motions impinging on small scale topography theory abstract observations and inverse models suggest that small scale turbulent mixing is enhanced in the southern ocean in regions above rough topography the enhancement extends o 1 km above the topography suggesting that mixing is supported by the breaking of gravity waves radiated from the ocean bottom in this study it is shown that the observed mixing rates can be sustained by internal waves generated by geostrophic motions flowing over bottom topography weakly nonlinear theory is used to describe the internal wave generation and the feedback of the waves on the zonally averaged flow vigorous inertial oscillations are driven at the ocean bottom by waves generated at steep topography the wave radiation and dissipation at equilibrium is therefore the result of both geostrophic flow and inertial oscillations differing substantially from the classical lee wave problem the theoretical predictions are tested versus two dimensional high resolution numerical simulations with parameters representative of

turning ocean mixing upside down abstractit is generally understood that small scale mixing such as is caused by breaking internal waves drives upwelling of the densest ocean waters that sink to the ocean bottom at high latitudes however the observational evidence that the strong turbulent fluxes generated by small scale mixing in the stratified ocean interior are more vigorous close to the ocean bottom boundary than above implies that small scale mixing converts light waters into denser ones thus driving a net sinking of abyssal waters using a combination of theoretical ideas and numerical models it is argued that abyssal waters upwell along weakly stratified boundary layers where small scale mixing of density decreases to zero to satisfy the no density flux condition at the ocean bottom the abyssal ocean meridional overturning circulation is the small residual of a large net sinking of waters driven by small scale mixing in the stratified interior above the bottom boundary layers and a slightly larger net upwelling driven b

a collision in 2009 as the origin of the debris trail of asteroid p 2010 a2 the peculiar object p 2010 a2 was discovered 1 in january 2010 and given a cometary designation because of the presence of a trail of material although there was no central condensation or coma the appearance of this object in an asteroidal orbit small eccentricity and inclination in the inner main asteroid belt attracted attention as a potential new member of the recently recognized 2 class of main belt comets if confirmed this new object would expand the range in heliocentric distance over which main belt comets are found here we report observations of p 2010 a2 by the rosetta spacecraft we conclude that the trail arose from a single event rather than a period of cometary activity in agreement with independent results 3 the trail is made up of relatively large particles of millimetre to centimetre size that remain close to the parent asteroid the shape of the trail can be explained by an initial impact ejecting large clumps of debris that disintegrated and dispersed almost immediately we determine that this was an asteroid collision that occurred around 10 february 2009

the geochemistry of phosphorus in different granite suites of the western carpathians slovakia the role of apatite and p bearing feldspar the geochemical behaviour of phosphorus in granites coupled with compositional variations in apatite discriminate the different genetic suites of variscan granitic rocks in the west carpathian orogenic belt meso variscan granites mostly of stype affinity show a good correlation between sio2 and p2o5 with decreasing amounts of p in the poorly and moderated fractionated granites and increasing phosphorus in the most evolved and late differentiation products the aluminium saturation index asi correlates negatively with bulk p contents in i type granites and positively with p in s type granites the phosphorus content of alkali feldspar mainly kfs is usually very low typically 0 05 wt p2o5 or not detected in the slightly differentiated granites in the latevariscan i s type granitoids phosphorus is hosted mainly in the early magmatic apatite but is present also in the late k feldspar up to 0 15 wt of p2o5 that formed from the residual melts in the postorogenic s type granites the bulk of the phosphorus occurs in alkali feldspar f0 3 wt p2o5 with a minor proportion present in primary early magmatic apatite clusters of small secondary apatite grains with a distinctive composition are distributed in alkali feldspar grains of the post orogenic s type granites this apatite has formed post magmatically from p released from p rich alkali feldspar during decreasing temperature by reaction with a fluid rich in volatiles including f and b and alkali and alkali earth metals a type granites have the lowest bulk phosphorus contents consequently phosphate minerals are relatively rare in this granite type and the alkali feldspar has negligible p2o5 contents except for sr the minor element contents in apatite partly correlate with the bulk composition of their host rocks and partly reflect some thermodynamic properties of melt the mn contents of apatite increase with the peraluminous character of the melt and with decreasing fo2 and so apatite from the s type granites has significantly higher mn contents than apatite from the i type granites apatite from a type granites is enriched in fe and hree reflecting the higher bulk fe and hree content of this granite type apatite from specialized s type granites is enriched in yand hree in general the cl and s content of apatite is higher in the basic members of the i type affinity granitic rocks d 2004 elsevier b v all rights reserved

apatite monazite and xenotime in metamorphic rocks this chapter focuses on phosphates that are significant in metamorphic rocks a quick survey of phosphate mineral descriptions at a commercial mineral web site revealed over 500 phosphate mineral names remarkably only three are common in metamorphic rocks apatite monazite and xenotime and this chapter is restricted to discussion of these minerals apatite monazite and to a lesser extent xenotime have enjoyed intensive study during the previous half century following world war ii considerable study was made of minerals that contain fissionable materials and the sometimes large concentrations of u and th in monazite culminated in a number of seminal papers on the occurrence of that mineral e g overstreet 1967 during the 1970s and early 1980s the study of apatite and monazite turned towards their role as a sink for rees and other trace elements in rocks e g watson 1980 watson and capobianco 1981 throughout this period monazite and to some extent xenotime enjoyed attention as a geochronometer e g parrish 1990 and through today this attention has continued to grow accessory minerals such as monazite xenotime and apatite have come to the forefront of research in metamorphic petrology in recent years for two reasons first it has recently been recognized that trace elements in metamorphic rocks and especially trace element zoning in garnet and other major phases contain considerable detailed information about the reaction history a rock has experienced coupled with the fact that diffusion of many trace elements in metamorphic minerals is in general considerably slower than diffusion of major elements in those same minerals the possibility has recently emerged of recovering details of metamorphic petrogenesis that were previously unattainable inasmuch as accessory minerals play a dominant role in the mass budget of many trace elements attention has naturally turned to their paragenesis it has also recently been discovered that

decay of a near inertial wave abstract the decay of a downward propagating near inertial wave was observed over four days during this short period the energy of the near inertial wave decreased by 70 the shear layers produced by the wave were regions of enhanced turbulent dissipation rates the authors estimate that 44 of the observed change in the near inertial energy was lost to turbulence estimates of the wave energy lost at the survey site due to the wave propagating out of the region were smaller energy lost by horizontal advection of the wave out of the survey region was more difficult to estimate the horizontal extent of the near inertial energy was unknown advection could account for more than half of the observed energy lost however the authors did not detect the near inertial wave during a 40 km 40 km adcp survey after completing the six day station

restratification of abyssal mixing layers by submesoscale baroclinic eddies for small scale turbulence to achieve water mass transformation and thus affect the large scale overturning circulation it must occur in stratified water observations show that abyssal turbulence is strongly enhanced in the bottom few hundred meters in regions with rough topography and it is thought that these abyssal mixing layers are crucial for closing and shaping the overturning circulation if it were left unopposed however bottom intensified turbulence would mix away the observed mixing layer stratification over the course of a few years it is proposed here that the homogenizing tendency of mixing may be balanced by baroclinic restratification it is shown that bottom intensified mixing if it occurs on a large scale topographic slope such as a midocean ridge flank not only erodes stratification but also tilts isopycnals in the bottom few hundred meters this tilting of isopycnals generates a reservoir of potential energy that can be tapped into by submesoscale baroclinic eddies the eddies slide dense water under light water and thus restratify the mixing layer similar to what happens in the surface mixed layer this restratification is shown to be effective enough to balance the homogenizing tendency of mixing and to maintain the observed mixing layer stratification this suggests that submesoscale baroclinic eddies may play a crucial role in providing the stratification mixing can act on thus allowing sustained water mass transformation through their restratification of abyssal mixing layers submesoscale eddies may therefore directly affect the strength and structure of the abyssal overturning circulation

abyssal mixing in the brazil basin one of the major objectives of the deep basin experiment a component of the world ocean circulation experiment was to quantify the intensity and spatial distribution of deep vertical mixing within the brazil basin in this study basin averaged estimates of deep vertical mixing rates are calculated using two independent methodologies and datasets 1 vertical fluxes are derived from large scale temperature and density budgets using direct measurements of deep flow through passages connecting the brazil basin to surrounding basins and a comprehensive hydrographic dataset within the basin interior and 2 vertical mixing rates are estimated from finescale bathymetry and hydrographic data using a functional relationship between turbulent dissipation and bathymetric roughness deduced from localized measurements of ocean microstructure obtained during the deep basin experiment the space time mean estimates of vertical mixing diffusivities across representative surfaces within the antarctic bottom water layer fell in the range 1 5 3 1024 m2 s 21 and were indistinguishable k from each other within the estimation uncertainties the mixing rates inferred from potential temperature budgets update and are consistent with earlier estimates that were based on less data mixing rates inferred from budgets bounded by neutral surfaces are not significantly different from the former this implies that lateral eddy fluxes along isopycnals are not important in the potential temperature budgets at least within the large estimation uncertainties unresolved processes such as cabbeling and low frequency variability which complicate inference of mixing from large scale budgets have been considered the agreement between diffusivity estimates based on a modeled relationship between bathymetric roughness and turbulent dissipation with those inferred from large scale budgets provides independent confirmation that the mixing rates have been accurately quantified