spinels and mg ilmenites from the noril sk 1 and talnakh intrusions and other mafic rocks of the siberian flood basalt province spinels from the mineralized noril sk 1 and talnakh intrusions show a broad and distinctive compositional spectrum from normal chromite to ti enriched aluminous magnetite in the talnakh intrusion in particular the range of spinel compositions extends across a compositional space where spinels are rare in other layered intrusions spinel compositions vary widely on a scale of individual thin sections and are influenced by the nature of the enclosing silicate phase spinels enclosed in olivines are less ti enriched than those outside olivine grains compositional variance in the spinels is attributed to variable but generally advanced reaction between cumulus chromite grains and solidifying trapped intercumulus liquid the advanced nature of the process is attributed to the open nature of the intrusions continuous prolonged flow through of hot magma enabled cumulates within the intrusions to remain above their solidus temperature for longer than would be normal for sills of comparable thickness the barren chibacheka river intrusion shows some of the same features but differs from talnakh in that spinel olivine pairs record equilibration temperatures higher than those at talnakh temperatures recorded by spinel olivine pairs at talnakh are anomalously low for such a small intrusion again indicating prolonged slow cooling consistent with a flow through model for the sill spinel compositions support a hypothesized comagmatic relationship between the chibacheka river intrusion and the ti cr rich gudchichinsky picritic basalts spinels in the noril sk and talnakh intrusions imply a parent magma with a lower cr al ratio than the gudchichinsky picritic basalts spinels from the siberian intrusions show a similar range in compositions to the feeder intrusions of the karoo flood basalt province jinchuan spinels share the features of high ti contents and anomalously low equilibration temperatures with the noril sk talnakh spinels mg ilmenites are a feature of the siberian and jinchuan intrusions they are attributed to crystallization of ilmenite from evolved trapped intercumulus liquid buffered by surrounding mg rich cumulus phases their existence implies moderately but not unusually ti rich parent magmas consistent with compositions of the siberian traps lavas

identification of the kuroshio extension its bifurcation and northern branch from altimetry and hydrographic data during october 1992 august 1999 spatial and temporal variability a methodology is proposed using altimter derived upper layer thickness and baroclinic transport to identify the kuroshio extension the bifurcation point and the northern branch by combining topex poseidon altimeter and climatological data within a two layer reduced gravity model results obtained from the japanese coast to 175 w show that the location of the bifurcation point presents interannual variability that is related with upstream conditions the longitude of the bifurcation point ranged from 147 to 160 e estimates of baroclinic transport at the kuroshio extension and its northern branch decrease steadily to the east trough the region of study from 35 to 11 and from 10 to 3 sv respectively

dislocations and slip systems of mantle minerals this chapter focuses on dislocations and slip systems that are responsible for the plastic flow of high pressure mantle minerals after briefly introducing some basic concepts on crystal plasticity we describe some recent experimental advances of the last decade that have contributed to our understanding of the rheology of mantle minerals among them we describe some progress in the achievement of deformation experiments under high pressure a more detailed review is presented by durham et al this volume we present then a novel transmission electron microscopy tem technique large angle convergent beam electron diffraction lacbed which is very well adapted to the characterization of dislocations in beam sensitive materials as well as the determination of dislocation burgers vectors and characters from the fine analysis of x ray diffraction peak broadening the present review is in the continuity of the paper entitled plastic rheology of crystals by poirier published in 1995 in mineral physics crystallography a handbook of physical constants agu reference shelf 2 poirier s paper reviewed the plasticity of some important minerals including olivine and pyroxenes concerning these two minerals the reader is invited to refer to poirier s contribution in 1995 poirier stated about high pressure mantle minerals despite their importance for the rheology of the transition zone and the lower mantle there is no information on the plasticity of the high pressure mantle minerals in the relevant conditions of temperature and pressure seven years later the situation has significantly evolved and is still rapidly changing it is the aim of this paper to highlight these recent advances plastic flow is basically a transport phenomenon controlled by the motion of defects point defects dislocations or grain boundaries the driving force is provided by the applied shear stress in many cases deformation is produced by the motion of dislocations and the present paper

the lower zone critical zone transition of the bushveld complex a quantitative textural study the lower zone critical zone boundary of the bushveld complex is an intrusion wide major stratigraphic transition from ultramafic harzburgite and pyroxenite in the lower zone to increasingly plagioclase richpyroxenitesandnoritesinthecriticalzone quantitative textural and compositional data for 29 samples through this transition show the following lower zone orthopyroxene grains are larger have higher aspect ratios are better foliated and have a lower trapped liquid component than those of the critical zone the larger grain size of the lower zone results in crystal size distribution plots that are rotated to lower slopes and intercepts relative to those in the critical zone although all rocks show differing amountsoffoliation mineral lineations are weak to absent these data are consistent with significant compaction driven recrystallization in the study section numerical modeling of concurrent compaction and crystallization provides a quantitative model of how the lower zone critical zone transition may have formed plagioclase is rare in the lower zone because compaction removes interstitial liquid before it reaches plagioclasesaturation however asthecrystalpilegrows plagioclase saturation is reached in the interstitial liquid before compaction is complete in more evolved pyroxenites producing more abundant but still modest amounts of plagioclase characteristic of the lower critical zone it is concluded that both the textures and the modal mineralogy are largely controlled by compaction and compactiondriven recrystallization primary magmatic textures are not preserved

the petrography and geochemistry of komatiite flows from the abitibi greenstone belt and a model for their formation abstract the petrology and geochemistry of komatiites at four localities in the abitibi greenstone belt are presented the effects of alteration crystal fractionation and partial melting on their geochemistry are considered it is concluded that na k ca sr and rb have been disturbed during seafloor alteration but the other major elements and the trace elements ni cr co sc ree y zr and hf have not been mobilized variations in the geochemistry within the komatiite flows are the result of olivine and sulphide fractionation the komatiites consisting of branching olivines skeletal textured komatiites and coarse parallel plate olivines a 3 spinifex textured zones may represent crescumulates rather than frozen liquids mass balance calculations indicate that the flows were open systems and could represent lava tubes 26 34 partial melting of a primitive earth mantle 1 4 c 1 chondrite will produce melts similar to the komatiites at each deposit in terms of major elements ni cr co sc hree and y however on average the concentrations of highly incompatible elements lree zr and hf in the komatiites only are 60 70 of the modelled concentrations thus indicating that the komatiites were derived from a mantle depleted in highly incompatible elements

mesoscale air sea interaction and its role in eddy energy dissipation in the kuroshio extension abstractusing the high resolution community earth system model cesm output this study investigates air sea interaction and its role in eddy energy dissipation in the kuroshio extension ke regi

quasi stationary jets transporting surface warm waters across the transition zone between the subtropical and the subarctic gyres in the north pacific 1 surface flow jets and associated sea surface temperature sst distribution are investigated in the northwestern north pacific using satellite derived surface currents and sst data that can resolve fine spatial scale structure the combined use of these data reveals warm tongue phenomena driven by surface geostrophic jets which extend northeastward in the kuroshio oyashio transition area they roughly coincide with the subarctic front saf defined as the 4 c isotherm at 100 m depth the phenomena appear throughout the year with seasonal cycles which do not correspond with that of the subarctic north pacific their positions are affected by bottom topography so that their quasi stationary and consistent features are suggested thus it is implied that these jets play an important role in transporting warm waters toward the subarctic region the time series of sst and current fields describe the jets year to year variability involving some changes in strength and connections with the kuroshio extension ke and demonstrate the effects of advection by the jets on sst fields when ke extends northward at its crests for 1999 2002 one of the jets along saf simultaneously strengthens resulting in high sst region directly over and along the south side of the jet hydrographic data show warm saline water intrusions along the jets their mean fields also reveal that these jets are vertically well developed forming a boundary between the subtropical and subarctic gyres in the north pacific

chromite in komatiites 3d morphologies with implications for crystallization mechanisms high resolution x ray computed tomography has been carried out on a suite of komatiite samples representing a range of volcanic facies chromite contents and degrees of alteration and metamorphism to reveal the wide range of sizes shapes and degrees of clustering that chromite grains display as a function of cooling history dendrites are spectacularly skeletal chromite grains formed during very rapid crystallization of supercooled melt in spinifex zones close to flow tops at slower cooling rates in the interiors of thick flows chromite forms predominantly euhedral grains large clusters up to a dozen of grains are characteristic of liquidus chromite whereas fine dustings of mostly individual 20 m grains form by in situ crystallization from trapped intercumulus liquid chromite in coarse grained olivine cumulates from komatiitic dunite bodies occurs in two forms as clusters or chains of euhedral crystals developing into chicken wire texture where chromite is present in supra cotectic proportions and as strongly dendritic semi poikilitic grains these dendritic grains are likely to have formed by rapid crescumulate growth from magma that was close to its liquidus temperature but supersaturated with chromite in some cases this process seems to have been favoured by nucleation of chromite on the margins of sulphide liquid blebs this texture is a good evidence for the predominantly cumulus origin of oikocrysts and in situ origin of heteradcumulate textures our 3d textural analysis confirms that the morphology of chromite crystals is a distinctive indicator of crystallization environment even in highly altered rocks

mesoscale sst dynamics in the kuroshio oyashio extension region abstractmesoscale eddies have been extensively studied based on the sea surface height anomaly ssha however it is the sea surface temperature anomaly ssta that is vital to the mesoscale eddy

long term variations of the kuroshio extension path in winter meridional movement and path state change abstractas an indicator of the kuroshio extension ke path the ke northern boundary kenb was detected based on the position of the strong winter sea surface temperature sst gradient between 142 and 155 e using high spatial resolution satellite derived sst for the 30 winters january to march from 1982 to 2011 the ke path showed meridional movement with a period of 10 15 yr and an amplitude of about 2 latitude the changes in latitudinal position of the ke path were initiated by a north south shift of the aleutian low al negative wind stress curl anomalies around 35 n in the eastern north pacific associated with a northward shift of the al induced a deepening of the main thermocline depth and then this deepening signal propagated westward reaching the ke region after about 3 yr where it caused the ke path to move northward the path state of the ke straight path convoluted path modulated on a time scale of 8 12 yr but this was not significantly correlated with the meridional movement of

southern ocean eddy phenomenology mesoscale eddies are ubiquitous features in the southern ocean yet their phenomenology is not well quantified to tackle this task we use satellite observations of sea level anomalies and sea surface temperature sst as well as in situ temperature and salinity measurements from profiling floats over the period 1997 2010 we identified over a million mesoscale eddy instances and were able to track about 105 of them over 1 month or more the antarctic circumpolar current acc the boundary current systems and the regions where they interact are hot spots of eddy presence representing also the birth places and graveyards of most eddies these hot spots contrast strongly to areas shallower than about 2000 m where mesoscale eddies are essentially absent likely due to topographical steering anticyclones tend to dominate the southern subtropical gyres and cyclones the northern flank of the acc major causes of regional polarity dominance are larger formation numbers and lifespans with a contribution of differential propagation pathways of long lived eddies areas of dominance of one polarity are generally congruent with the same polarity being longer lived bigger of larger amplitude and more intense eddies extend down to at least 2000 m in the acc eddies show near surface temperature and salinity maxima whereas eddies in the subtropical areas generally have deeper anomaly maxima presumably inherited from their origin in the boundary currents the temperature and salinity signatures of the average eddy suggest that their tracer anomalies are a result of both trapping in the eddy core and stirring

numerical experiments on the movement of a warm core ring with the bottom slope of a western boundary numerical experiments are performed to investigate the effects of the bottom slope of a western boundary on realistic warm core rings using a primitive equation sigma coordinate model warm core rings which initially have baroclinic velocity near a steep bottom slope gradually move northward but those with barotropic velocity do not barotropic velocity on the slope immediately disperses as a topographic rossby wave while baroclinic velocity is retained since the northward movement is caused by an effect very much like the image effect which is originally the effect of a free slip wall the authors term this effect the equivalent image effect the equivalent image effect increases as a slope becomes steeper and bottom friction becomes weaker and vice versa it seems that a steep slope acts like a wall and the bottom friction of a steep slope corresponds to the lateral viscous effect of a wall however the effect of a slope on a warm core ring is different from that of a wall in that ring slope interactions take place at the lower part of the ring because the velocity of a warm core ring is weak in deep layers ring slope interactions are moderate and the leakage of the interior fluid of a ring seen in ring wall interactions is not apparent while the viscous effect is weaker than that of a no slip wall as well these results are applied to the northward movement of kuroshio warm core rings and to warm eddies in the gulf of mexico

the origin of chromitites and related pge mineralization in the bushveld complex new mineralogical and petrological constraints this article reports a study of chromitites from the lg 1 to the ug 2 3 from the bushveld complex chromite from massive chromitite follows two compositional trends on the basis of cation ratios trend a decreasing mg mg fe with increasing cr cr al trend b decreasing mg mg fe with decreasing cr cr al the chromitites are divided into five stages on the basis of which trend they follow and the data of eales et al chemical geology 88 261 278 1990 on the behaviour of the mg fe ratio of the pyroxene and whole rock sr isotope composition of the environment in which they occur following eales et al chemical geology 88 261 278 1990 the different characteristics of the stages are attributed to the rate at which new magma entered the chamber and the effect of this on aal2o3 and in the case of stage 5 the appearance of cumulus plagioclase buffering the aal2o3 the similarity of pge profiles across the mg 3 and mg 4 chromitites that are separated laterally by up to 300 km and the variation in v in the ug 2 argue that the chromitites have largely developed in situ modelling using the programme melts shows that increase in pressure mixing of primitive and fractionated magma felsic contamination of primitive magma or addition of h2o do not promote crystallization of spinel before orthopyroxene in general they hinder it and that the cr2o3 content of the magma was of the order of 0 25 wt less than 20 of the chromite in the magma is removed before orthopyroxene joins chromite which implies a 13 km thickness of magma for the critical zone it is suggested that the large excess of magma has escaped up marginal structures such as the platreef the pge profile of chromitites depends on whether sulphide accumulated or not along with chromite modelling shows that contamination of critical zone magma with a felsic melt will induce sulphide immiscibility although not chromite precipitation the lg 1 to lg 4 chromitites developed without sulphide whilst those from the lg 5 upwards had associated liquid sulphide much of the sulphide originally in the lg 5 and above has been destroyed as a result of reaction with the chromite

water mass structure of warm and cold anticyclonic eddies in the western boundary region of the subarctic north pacific vertical profile data of temperature and salinity from various sources were analyzed together with satellite altimeter data to investigate the water mass characteristics of warm and cold anticyclonic eddies in the western boundaryregionof the subarctic north pacific a densedistributionof anticyclonic eddieswith warm and saline core water occurred near the kuroshio extension and the distribution extends northward northeastward into the western subarctic gyre along the japan and kuril kamchatka trenches eddies with cold and fresh core water are found mainly around the oyashio southward intrusions and farther north near the kuril islands based on the heat content anomaly integrated over 50 200 dbar 85 of the anticyclonic eddies within the study area 358 508n 1408 1558e have a warm and saline core and 15 have a cold and fresh core warm and saline eddies around the japan and kuril kamchatka trenches have a double core structure with a cold and freshwater mass located below the warm core the northward propagation of these eddies along the trench line results in a large northward heat salinity transport in the upper 400 dbar 250 dbar and a negative salinity transport below 350 dbar the lower core water is colder and fresher on isopycnal surfaces at around 26 70sucompared with the climatology given that the 26 70su isopycnal surface does not outcrop in the open north pacific an alignment process is suggested to occur between the warm and saline and the cold and fresh anticyclonic eddies in the upper and intermediate layers respectively

dynamics of a quasi stationary jet along the subarctic front in the north pacific ocean the western isoguchi jet an ideal two layer model abstractthe dynamics of a quasi stationary jet along the subarctic front in the north pacific ocean the western isoguchi jet were investigated using an idealized two layer model the experiments suggested that a seafloor topography which is 500 m high produces a jet along its eastern flank the formation mechanism of the jet can be explained via baroclinic rossby wave characteristics baroclinic rossby waves propagate along characteristic curves which are significantly distorted by anticyclonic barotropic flow on the seafloor topography a baroclinic surface jet is formed where a characteristic curve originating in the subtropical gyre and one originating in the subpolar gyre meet because the pycnocline depth varies discontinuously at this location the barotropic flow on the seafloor topography is induced by eddies

geographical variability of the first baroclinic rossby radius of deformation global 1 83 18 climatologies of the first baroclinic gravity wave phase speed c1 and the rossby radius of deformation l1 are computed from climatological average temperature and salinity profiles these new atlases are compared with previously published 5 83 58 coarse resolution maps of l1 for the northern hemisphere and the south atlantic and with a 1 83 18 fine resolution map of c1 for the tropical pacific it is concluded that the methods used in these earlier estimates yield values that are biased systematically low by 5 15 owing to seemingly minor computational errors geographical variations in the new high resolution maps of c1 and l1 are discussed in terms of a wkb approximation that elucidates the effects of earth rotation stratification and water depth on these quantities it is shown that the effects of temporal variations of the stratification can be neglected in the estimation of c1 and l1 at any particular location in the world ocean this is rationalized from consideration of the wkb approximation

a frequency dependent description of propagating sea level signals in the kuroshio extension region abstracthilbert empirical orthogonal function analysis is used to provide a frequency dependent description of observed sea level variability in the kuroshio extension region 1993 2012 inclusive the dominant high frequency mode periods between 140 and 350 days describes signals that propagate westward with the largest amplitudes in the vicinity of the shatsky rise and emperor seamounts based on the close correspondence between the variance of the high frequency variability and the underlying bathymetry it is speculated that this mode is driven by jet bathymetry interactions the dominant low frequency mode periods longer than 350 days is explained in terms of wind forced jet trapped rossby waves that propagate along the mean kuroshio extension jet one of the most surprising findings of this study is that sea level changes north of the jet in the meander region anticipate changes south of the jet by about 3 yr based on correlations of observed sea level with the pacific decadal oscillation and

eddy induced heat transport in the subtropical north pacific from argo tmi and altimetry measurements basin scale heat transport induced by mesoscale oceanic eddies is estimated by combining satellite derived sea surface height and temperature temperature data are from the trmm microwave imager tmi data with argo float temperature salinity data in the north pacific ocean subtropical gyre warm cold temperature anomalies of mesoscale eddies are found to be consistently located to the west of high low ssh anomalies the phase misalignment between the temperature and velocity anomalies however is largely confined to the seasonal thermocline causing most of the eddy induced heat transport to be carried in the surface 200 m layer by establishing a statistical relationship between the surface and depth integrated values of the eddy heat transport the basin scale eddy heat transport is derived from the concurrent satellite ssh sst data of the past six years in the kuroshio extension region the meandering zonal jet is found to generate oppositely signed eddy heat fluxes as a result the zonally integrated poleward heat transport associated with the kuroshio extension is at a level o 0 1 pw smaller than the previous estimates based on turbulent closure schemes large poleward eddy heat transport is also found in the subtropical north pacific along a southwest northeast tilting band between taiwan and the midway islands this band corresponds to the region of the subtropical front and it is argued that the relevant temperature field for identifying this band in the turbulent closure scheme models should be that averaged over the seasonal thermocline

on the seasonal eddy variability in the kuroshio extension abstractusing a recently developed tool multiscale window transform mwt and the mwt based canonical energy transfer theory this study investigates the seasonal eddy variability in the kuroshio

foraging spots of streaked shearwaters in relation to ocean surface currents as identified using their drift movements ocean currents are in continuous motion and strongly influence oceanic ecosystems in situ observation of currents is of primary importance for understanding how marine animals respond to ocean surface currents at various scales and for realizing effective ecosystem based management and realistic oceanographic modelling we developed a new method for obtaining in situ current measurements by using seabirds as lagrangian current sensors akin to drifting buoys we deployed high resolution global positioning system gps loggers on streaked shearwaters calonectris leucomelas foraging in the oyashio tsugaru warm current confluence in japan which is one of the most productive oceans in the world the seabirds repeatedly performed foraging trips including searching for prey and resting on the sea surface over several hundred kilometres the seabirds spent half of their time resting on the water surface and tended to be passive drifters we inferred that the drift movements of c leucomelas provided a direct and detailed description of the ocean surface currents because currents deduced from their drift movements were in good agreement with ocean surface currents derived from in situ and satellite data in addition we extracted details of shearwaters intense searching flights associated with feeding i e foraging spots from gps tracks c leucomelas did not forage at the core of anticyclonic eddies rather they used the boundary areas between eddies and the edge of eddies where primary productivity and prey density are thought to be high our study demonstrated that animal borne gps data can provide a detailed and cost efficient tool for observing ocean surface currents and can reveal the ways in which marine animals respond to these currents at a fine scale

reaction relationships of chrome spinels in igneous rocks further evidence from the layered intrusions of rhum and mull inner hebrides scotland compositions of chrome spinels in peridotites from the layered igneous rocks of rhum and of the ben buie intrusion mull show evidence of post depositional reaction relationships with the cumulus olivine and or the intercumulus liquid some seam forming spinels in the ben buie intrusion are highly aluminous more so than those in the rhum intrusion occasional zoned spinels in both intrusions show enrichment in al towards their rims the evidence suggests that the spinel reaction trend involving cr al exchange proceeds in the direction of al enrichment equilibrium between chrome spinel and cumulus olivine appears to have been attained rarely thus limiting the application of the olivine spinel geothermometer

distribution and modification of north pacific intermediate water in the kuroshio oyashio interfrontal zone abstract a multiship ctd survey was conducted in the kuroshio oyash interfrontal zone in the area of 30 41 n 140 e 180 from may to june 1992 to examine the distribution modification process and formation site of north pacific intermediate water npiw low salinity oyashio water and high salinity kuroshio water merge along the kuroshio extension just off the east coast of japan and together flow eastward eastward geostrophic transport and salinity across the kuroshio strong current indicate that the mixture of the kuroshio and oyashia waters along the kuroshio extension can produce new npiw transport estimate suggests that the new npiw bifurcates into the interfrontal zone and into the recirculation of the subtropical gyre a salinity minimum structure can he also created due to the isopycnal mixing along the kuroshio extension between the oyashio and kuroshio waters which have different salinity and vertical velocity structures the low salinity oyashio water seen along the oyashio branches and t

the upper critical zone of the bushveld complex and the origin of merensky type ores the mg number mg mg fe atomic ratio of bronzite in each unit at the top of the critical zone of the bushveld complex decreases upward in a manner consistent with fractional crystallization the base of each unit is marked by an increase in the mg number suggesting that crystallization of fresh magma is responsible for the initiation of the unit bulk trace and major element concentrations in pegmatoids of the merensky reef which itself forms the basal part of one of a series of these cyclic units are similar to those in medium grained feldspathic bronzitite the base of each unit is also marked by pockets or a layer of sulfide with a higher ni cu and much higher pt cu ratio than the sulfides of the remainder of the unit thus the pt tenor alternates from high to low three times upward through the three units these data indicate strongly that the pt tenor was established with the stratigraphy of the rocks and are inconsistent with models calling upon upward migration of hydrothermal or magmatic fluids to enrich the sulfides in platinum group elements there are no features in the rocks to indicate that fluids could have been channeled to flow laterally for the tens to hundreds of kilometers occupied by continuous merensky reef a model based on that of campbell et al 1983 in which small amounts of sulfides form during injection of fresh magma as a turbulent plume and then settle after becoming thoroughly mixed with a large mass of magma accounts well for all of our observations and many other features of the upper part of the critical zone

water behaviour in limestones as a function of pores structure application to frost resistance of some lorraine limestones abstract the frost resistance of limestones is determined by their ability to withstand damage caused by water freezing in microscopic pores the factors which limit frost action are connected with the saturation state of the material and the distribution of water in the porous media the behaviour of fluid in some limestones from the lorraine area of northeast france was studied in laboratory experiments carbonate grainstones with bimodal porous networks have high values of air trapped porosities and permeabilities and their degree of saturation resulting from capillary absorption or total immersion is restricted to 60 for these materials the predictive frost resistance is high the result of frost action on limestones with unimodal porous networks depends on the rock texture mudstone to packstone more or less well cemented the influence of parameters such as pore radius pore shape permeability and the strains developed during freezing these relations are confirmed by in situ observations and by experiments with frost in a climatic cabinet

relationships between total alkalinity in surface water and sea surface dynamic height in the pacific ocean improved spatial and temporal representation of total alkalinity ta is expected to be an important component in monitoring changes in the oceanic carbon cycle and acidification over the coming decades for this reason previous authors have sought to develop and apply empirical methods to characterize ta in the surface ocean however there are regions such as the north pacific that have proven difficult to successfully represent through empirical relationships based on temperature and salinity with linear regression here we propose a new empirical approach for reconstructing ta for the pacific basin using sea surface salinity and sea surface dynamic height ssdh we propose five zones of the pacific basin where the empirical relationships are applied separately the root mean square error of the fittings of these equations to the measured ta is 7 8 mol kg 1 the ssdh based empirical equation helps especially to represent the ta in the north pacific subtropical subarctic frontal zone where salinity normalized ta as well as other oceanographic variables exhibits a large meridional gradient and sizeable formation of central mode water and subtropical mode water occurs

interdecadal decrease of the oyashio transport on the continental slope off the southeastern coast of hokkaido japan we investigated the interdecadal trend of oyashio velocity and transport during 1993 2011 based mainly on linear trend analysis of altimetry and in situ temperature salinity data from a monitoring line a line off the southeastern hokkaido coast significant trends of increasing sea level were detected on the continental slope north of the kuril kamchatka trench sea level anomaly data revealed a localized clockwise circulation centered near the trench the suggestion being that the strength of the oyashio on the slope and the offshore return flow had decreased the oyashio mainstream seemed to have shifted from a nearshore to an offshore path steric heights estimated from the a line data exhibited an increasing trend north of the trench where 50 80 of the increase was determined by halosteric components attributable to a trend of decreasing salinity in the subsurface the trend of decreasing salinity was related to downward displacement of isohaline isopycnal surfaces the largest displacement was above the trench horizontal pressure gradients associated with southwestward flows on the slope were weakened the oyashio transport decreased by 8 9 sv 106 m3 s 1 in 19 years a mesoscale eddy analysis revealed that clockwise eddies appeared more frequently in recent years near the trench around the a line and could decrease the oyashio transport a baroclinic long rossby wave model also predicted that a large scale baroclinic response to the wind stress could weaken the oyashio velocity in the upper layer dynamical linkage between the localized eddies and large scale response remains to be clarified in future work

platinum group element chromitite associations in the bushveld complex new and recently published platinum group element data of chromite rich layers in the bushveld complex are evaluated chondrite normalized platinum group element plots of these data show that trends for chromitite layers differ from that of the merensky reef the data furthermore indicate remarkable consistencies in compositional trends for many kilometers along strike of individual layers suggesting that the conditions of formation of chromitite layers and their associated platinum group element mineralization were very uniform over large areas of the magma chamber significant differences in the proportions of platinum group elements within a particular layer are only evident on a regional scale the platinum group minerals of the middle group of chromitite layers in the marikana area of the western bushveld are mainly sulfides and arsenides laurite is the most common platinum group mineral and is mostly enclosed by chromite a variety of other platinum group minerals occur in close association with base metal sulfides extremely low bulk sulfur content in the chromitite layers is ascribed to a postcumulus loss of sulfur postcumulus loss of sulfur and the existence of laurite enclosed within chromite casts doubt on the validity of any petrogenetic models for platinum mineralization in chromitite rich layers based on partition coefficients and the r factor

response of rapidly developing extratropical cyclones to sea surface temperature variations over the western kuroshio oyashio confluence region the dynamical response of rapidly developing extratropical cyclones to sea surface temperature sst variations over the western kuroshio oyashio confluence wkoc region was examined by using regional cloud resolving simulations this study specifically highlights an explosive cyclone that occurred in early february 2014 and includes a real sst experiment cntl run and two sensitivity experiments with warm and cool sst anomalies over the wkoc region warm and cool runs the results derived from the cntl run indicated that moisture supply from the ocean was enhanced when the dry air associated with the cold conveyor belt ccb overlapped with warm currents further the evaporated moisture contributed substantially to latent heat release over the bent back front with the aid of the ccb leading to cyclone intensification and strengthening of the asymmetric structure around the cyclone s center such successive processes were more active in the warm run than in the cool run the dominance of the zonally asymmetric structure resulted in a difference in sea level pressure around the bent back front between the two runs the wkoc sst variations have the potential to affect strong wind distributions along the ccb through modification of the cyclone s inner system additional experiments with two other cyclones showed that the cyclone response to the wkoc sst variations became evident when the ccb north of the cyclone s center overlapped with that region confirming that the dry nature of the ccb plays an important role in latent heat release by allowing for larger moisture supply from the ocean

komatiites and nickel sulfide ores of the black swan area yilgarn craton western australia 2 geology and genesis of the orebodies the black swan ultramafic succession hosts a number of magmatic fe ni cu pge sulfide ore shoots ranging from high grade massive ore to low grade disseminated sulfides of these the most economically significant is the silver swan massive sulfide orebody associated with the basal contact of the succession the deposit varies in thickness between 5 and 20 m reaches a n s strike length of 75 m extends for at least 1 2 km of vertical plunge and is open at depth overlying matrix net textured ore is rare inclusions of dacite are abundant within the lower 5 m of the massive sulfide they range from angular fragments through smooth sinuous and plumose morphologies to fine lace like intergrowths with the sulfide matrix and comprise variable proportions of cores of porphyritic dacite and carapaces with skeletal plagioclase phenocrysts dynamic crystallisation and kinetic melting textures in the carapaces indicate that the inclusions have been heated to various temperatures some well above their liquidus temperature the composition of the inclusions ranges from a perfect match with the immediate footwall dacites to mixtures of dacite with up to 30 komatiite the consistent thickness of the inclusion bearing basal layer within the massive sulphide is interpreted as the extent of 3 d physical connectivity between the inclusions and a partially molten underlying hybrid layer primary contacts between the silver swan massive sulfide orebody and overlying ultramafic rocks are marked by thin rinds containing coarse grained chevron textured chromites with skeletal textures compositions of these chromites match those from kambalda perseverance and other localities and are inconsistent with a metamorphic origin they are interpreted as markers of primary magmatic contacts the combination of this feature with the general paucity of matrix ore implies that the massive ore accumulated and solidified before the accumulation of the overlying thick sequence of olivine cumulates taken together with observations on the internal fractionation of platinum group elements within the massive ores these observations are consistent with a model where the massive ore were emplaced at the floor of a small partially drained lava tube the floor of the tube had been previously heated by passage of large volumes of lava such that it had reached its melting range the felsic inclusions within the ore are the result of buoyant ascent of partially molten substrate into the ore magma this constitutes strong evidence for the operation of thermo mechanical erosion during ore emplacement the disseminated cygnet and black swan orebodies show a number of distinctive features cygnet contains a assemblage of clasts and inclusions which are interpreted as the result of rip up transport and redeposition of sulfides from a pre existing massive sulfide orebody of which black duck may be a remnant the black swan orebody by contrast does not show xenolithic features but is characterised by an association of sulfide blebs with segregation vesicles and by unusually coarse grained olivine the black swan orebody is interpreted as the result of transport of sulfide droplets within a lava charged with a suspended load of coarse olivine crystals

mesoscale eddies in the northwestern pacific ocean three dimensional eddy structures and heat salt transports the region encompassing the kuroshio extension ke in the northwestern pacific ocean 25 n 45 n and 130 e 180 e is one of the most eddy energetic regions of the global ocean the three dimensional structures and transports of mesoscale eddies in this region are comprehensively investigated by combined use of satellite data and argo profiles with the allocation of argo profiles inside detected eddies the spatial variations of structures of eddy temperature and salinity anomalies are analyzed the results show that eddies predominantly have subsurface near surface intensified temperature and salinity anomalies south north of the ke jet which is related to different background stratifications between these regions a new method based on eddy trajectories and the inferred three dimensional eddy structures is proposed to estimate heat and salt transports by eddy movements in a lagrangian framework spatial distributions of eddy transports are presented over the vicinity of the ke for the first time the magnitude of eddy induced meridional heat freshwater volume transport is on the order of 0 01 pw 103 m3 s the eddy heat transport divergence results in an oceanic heat loss south and heat gain north of the ke thereby reinforcing and counteracting the oceanic heat loss from air sea fluxes south and north of the ke jet respectively it also suggests a poleward heat transport across the ke jet due to eddy propagation

image analysis and composition of platinum group minerals in the j m reef stillwater complex detailed imaging bulk geochemical analyses and laser ablation icp ms analyses were conducted on mineralized samples from the platinum group element pge bearing j m reef stillwater complex montana the aims of the study were to determine which phases are the main hosts of the pge to examine the textural relationships of the pge bearing minerals and the associated base metal sulfides silicates and secondary magnetites the platinum group minerals pgm observed in the studied samples consist of pd or pt sulfides pt fe alloy isoferroplatinum pd or pt tellurides and pd cu alloy skaergaardite with minor native pd ru ir os s sub 2 laurite and au pd ag alloy palladian electrum these minerals account for all the pt half the pd ru and ir and a smaller proportion of the os in whole rocks the balance being found in the base metal sulfide most of these pgm are closely associated with base metal sulfides either included in the base metal sulfide or located at the contact between the base metal sulfide and the silicate or oxide minerals the textures of the pgm within and at the margins of the base metal sulfide suggest that they exsolved from the sulfides we suggest that the pge ni cu and te partitioned into a magmatic sulfide liquid that crystallized into base metal sulfide the pt fe alloys and some of the pd sulfides exsolved from the base metal sulfide during desulfurization at fairly high temperatures in contrast the skaergaardite and some pd sulfides are found in association with secondary magnetite and probably formed at relatively low temperatures approximately 250 degrees 465 degrees c during a second fluid migration event the pd pt ratio of the reef approximately 3 3 is higher than most mafic magmas and the pd pt ratio of the footwall is lower 0 3 0 7 it is possible that some of the pd in the reef was leached from the underlying rocks and deposited in the reef as pgm associated with secondary magnetite

platinum ore in three dimensions insights from high resolution x ray computed tomography platinum group elements referred to as pge comprising pt pd rh ru ir and os are strategic metals with a wide variety of industrial applications most of the world s pge production is mined from large mafic ultramafic intrusions such as the bushveld complex in south africa which currently provides 75 of the world s pt production the pge mineralization is found within distinctive layers tens to hundred of centimeters thick but extending laterally for many tens of kilometers where the pge occur at low parts per million levels as platinum group minerals pgm and in solid solution within disseminated base metal sulfides there is still heated debate at the most fundamental level about the mode of formation of this class of deposit genetic models range from primary magmatic sulfide collection to concentration by migrating halogen rich fluids a crucial line of evidence is the spatial relationship between the pgm which are the most important pge bearing phases and the base metal sulfide aggregates or blebs so far all observations have been carried out using two dimensional mineralogical studies where textural relationships with other minerals are ambiguous and with statistical limitations owing to sampling of trace phases intersecting random surfaces we present the first detailed three dimensional in situ analysis of the pgm at the sample scale using high resolution x ray computed tomography coupled with conventional microscopic and mineralogical study we find a striking and highly consistent relationship of pgm grains with the edges of complex shaped magmatic sulfide blebs and the intersection of these blebs with chromite silicate grain boundaries these new three dimensional observations strongly support an orthomagmatic model coupled with nucleation and growth of pgm at the margins of sulfide liquid droplets

morphology and microstructure of chromite crystals in chromitites from the merensky reef bushveld complex south africa the merensky reef of the bushveld complex consists of two chromitite layers separated by coarse grained melanorite microstructural analysis of the chromitite layers using electron backscatter diffraction analysis ebsd high resolution x ray microtomography and crystal size distribution analyses distinguished two populations of chromite crystals fine grained idiomorphic and large silicate inclusion bearing crystals the lower chromitite layer contains both populations whereas the upper contains only fine idiomorphic grains most of the inclusion bearing chromites have characteristic amoeboidal shapes that have been previously explained as products of sintering of pre existing smaller idiomorphic crystals two possible mechanisms have been proposed for sintering of chromite crystals 1 amalgamation of a cluster of grains with the same original crystallographic orientation and 2 sintering of randomly orientated crystals followed by annealing into a single grain the ebsd data show no evidence for clusters of similarly oriented grains among the idiomorphic population nor for earlier presence of idiomorphic subgrains spatially related to inclusions and therefore are evidence against both of the proposed sintering mechanisms electron backscatter diffraction analysis maps show deformation related misorientations and curved subgrain boundaries within the large amoeboidal crystals and absence of such features in the fine grained population microstructures observed in the lower chromitite layer are interpreted as the result of deformation during compaction of the orthocumulate layers and constitute evidence for the formation of the amoeboid morphologies at an early stage of consolidation an alternative model is proposed whereby silicate inclusions are incorporated during maturation and recrystallisation of initially dendritic chromite crystals formed as a result of supercooling during emplacement of the lower chromite layer against cooler anorthosite during the magma influx that formed the merensky reef the upper chromite layer formed from a subsequent magma influx and hence lacked a mechanism to form dendritic chromite this accounts for the difference between the two layers

contrasting platinum group element concentration patterns in cumulates of the bushveld complex chromite rich lithologies in both the lower and the critical zones of the bushveld complex in the potgietersrus area display flat chondrite normalized platinum group element pge concentration patterns whereas those of associated sulphide bearing but chromite poor rocks are considerably steeper the low pt pd os ir ru ratio in the chromite bearing rocks is maintained irrespective of the amount of sulphide or chromite in the rock this feature suggests that the partitioning of the individual pge into pge bearing phases during conditions in the magma under which crystallization of chromite in excess of the normal cotectic amounts was favoured differed from conditions under which an immiscible sulphide liquid separated from the same magma in the absence of enhanced chromite crystallization these changes in the partitioning coefficients of the individual pge are considered to reflect changes in the solubility of these elements in response to variations in the intensive parameters in the magma necessary to bring about the enhanced crystallization of chromite

the first occurrence of platinum group minerals pgm in a chromite deposit in the eastern desert egypt the platinum group mineralogy pgm of the chromitite from gebel lawi in the southeastern desert has been investigated the most abundant base metal sulfides bms associated with the lawi chromite are pentlandite millerite and heazlewoodite the major platinum group minerals identified were as follows laurite irosru s2 osmian iridium osir hollingworthite rhass tellurian arsenopalladinite pdtesbas polarite pdhg besides cuprian palladian gold cupdau a pd sb hg and hgte phases laurite and osmian iridium occur preferentially in chromite os ir commonly forms composite pgm with laurite hollingworthite and tellurian arsenopalladinite are included within serpentine and close to the base metal sulfides the cuprian palladian gold shares boundaries with chromite polarite together with the pd sb hg and hgte phases are embedded in serpentine palladium is the most abundant pge in the gebel lawi chromite

from geometry to dynamics of microstructure using boundary lengths to quantify boundary misorientations and anisotropy the microstructure of a quartzite experimentally deformed and partially recrystallised at 900 jc 1 2 gpa confining pressure and strain rate 10 6 s was investigated using orientation contrast and electron backscatter diffraction ebsd boundaries between misoriented domains grains or subgrains were determined by image analysis of orientation contrast images in each domain ebsd measurements gave the complete quartz lattice orientation and enabled calculation of misorientation angles across every domain boundary results are analysed in terms of the boundary density which for any range of misorientations is the boundary length for that range divided by image area this allows a more direct comparison of misorientation statistics between different parts of a sample than does a treatment in terms of boundary number the strain in the quartzite sample is heterogeneous a 100 150 am low strain partially recrystallised subarea c was compared with a high strain completely recrystallised subarea e the density of high angle 10j boundaries in e is roughly double that in c reflecting the greater degree of recrystallisation low angle boundaries in c and e are produced by subgrain rotation in the low angle range 0 10j boundary densities in both c and e show an exponential decrease with increasing misorientation the densities scale with exp h k where k is approximately 2j in c and 1j in e in other words e has a comparative dearth of boundaries in the 8 10j range we explain this dearth in terms of mobile high angle boundaries sweeping through and consuming low angle boundaries as the latter increase misorientation through time in e the density of high angle boundaries is larger than in c so this sweeping would have been more efficient and could explain the relative paucity of 8 10j boundaries the boundary density can be generalised to a directional property that gives the degree of anisotropy of the boundary network and its preferred orientation despite the imposed strain the analysed samples show that boundaries are not on average strongly aligned this is a function of the strong sinuosity of high angle boundaries caused by grain boundary migration low angle boundaries might be expected on average to be aligned in relation to imposed strain but this is not found

remotely propagating salinity anomaly varies the source of north pacific ventilation abstract the dense shelf water dsw produced in the sea of okhotsk causes the deepest ventilation in the north pacific and plays a key role in overturning to the depth of intermediate layers salinity determines the density of dsw in cold seas such as this however the variability of dsw salinity has yet to be quantified and its causes remain unknown because of the paucity of available observation data here we describe the variability of dsw salinity in the period from 1950 to 2005 through the analysis of a newly compiled hydrographic dataset expanded with russian measurements in the sea of okhotsk and the bering sea dsw salinity exhibits a decreasing trend of 0 0024 0 0015 y 1 over 1950 2005 in addition to decadal scale variability with a typical magnitude of 0 1 we have found that dsw variability is controlled largely by surface salinity anomalies that propagate along pathways associated with ocean currents from the bering sea to the sea of okhotsk these salt pathways can be traced farther upstream to the alaskan stream and western subarctic gyre we suggest that this is a possible pathway which consists of a previously undefined upper branch of the north pacific overturning cell along this pathway the effects of the nodal tide that has an 18 6 year period may also propagate from the kuril straits and the aleutian passes our results indicate that long term atmospheric variations and enhanced hydrological cycles over the north pacific which are associated with global climate changes are conducted to the intermediate layer through surface salt pathways and subsequent dsw ventilation and lead to variability in material circulation and biogeochemical cycles

distribution of sei whales balaenoptera borealis in the subarctic subtropical transition area of the western north pacific in relation to oceanic fronts the subarctic subtropical transition area of the western north pacific is an important summer feeding grounds of sei whales the oceanographic structure and circulation of this area are largely determined by strong oceanic fronts and associated geostrophic currents namely the polar front pf subarctic front saf and kuroshio extension front kef the relationship between the distribution of sei whales and oceanographic fronts was investigated using a generalized additive model gam and the cetacean sighting survey data and oceanographic observations in july from 2000 to 2007 were used in the analysis the number of individual sei whales was used as the response variable while the distances from the pf saf and kef to the whales were used as explanatory variables along with the longitude values sei whales were concentrated north and south of the saf and the areas from 250 to 300 km north and from 100 to 200 km south of the saf were estimated as high density areas of sei whales the entire inter frontal zone between the pf and saf featured an elevated concentration of sei whales and the area south of the pf and along the saf was identified as an important feeding ground of sei whales in july from 2000 to 2007

cold core anticyclonic eddies south of the bussol strait in the northwestern subarctic pacific abstract summer hydrographic surveys from 1993 to 1997 in the area south of the kuril islands in the northwestern subarctic pacific showed the existence of anticyclonic eddies south of the bussol strait at almost the same location but with variable sizes and intensities depending on the year every eddy had a cold low salinity and low potential vorticity core suggesting a strong influence from the okhotsk sea water two formation processes and annual variations were found with satellite data analyses one is the case where eddies are locally formed south of the bussol strait and intensified from summer to fall with the supply of okhotsk sea water as observed in 1993 in the other case kuroshio warm core rings that had translated northeastward are arrested near the bussol strait and amplified with the supply of okhotsk sea water as seen from summer to autumn in 1995 in winter eddies tend to move northeastward with decay the 1992 eddy moved northeastward then northward in winter and was eventually

how eddies gain retain and release water a case study of a hokkaido anticyclone a lagrangian methodology is elaborated to identify the origin of water masses in the kuroshio oyashio frontal zone where waters of the kuroshio extension and oyashio current and of the japan and okhotsk seas converge it allows one to track the evolution of mesoscale eddies during the satellite altimetry era and to document how they gain retain and release water masses of different origin the methodology is applied to study warm core mesoscale anticyclones propagating along the japan and kuril trenches near the eastern coast of hokkaido island that have been observed from january 1 1993 to december 10 2016 in an altimetry based velocity field the hokkaido eddy sampled by profiling floats and a few cruises in 2003 and 2004 is analysed in detail in order to compare lagrangian simulation results to observations

periglacial slope deposits and their pedogenic implications in germany abstract disconformities within soil parent materials are frequently reported from locations throughout the world but they are rarely within the goals of systematic research this article provides an overview of the current state of knowledge on such materials and their pedogenic relevance in germany it intends to encourage further discussion on stratified soils in other parts of the world the slope deposits in germany are divided into 1 the upper layer that is ubiquitously distributed and displays a relatively constant thickness 2 the intermediate layer that is restricted to flat relief to hollows and to lee ward facing slopes and 3 the basal layer that is rather widespread again both the upper and intermediate layer contain intermixed loess while the basal layer is free of loess these layers were mainly formed by periglacial solifluction such deposits are referred to as cover beds the upper layer formed during the younger dryas within a relatively short episode in contrast the lower layers may be diachronous nevertheless they display recurring vertical sequences this is probably due to the fact that loess free layers usually could not deposit as long as there was loess in the environs thus the last phase of surface wash during which older loess was removed determines the age of the lower layers the composition of the layers differs reflecting the varying portions of loess and of rock allocated from upslope in twofold sequences the cover beds influence the formation of the soils as they provide weathered material and as their boundaries where properties such as texture and bulk density abruptly change determine the soil horizon boundaries some pedogenic processes are favored oxidation depletion of clay or hindered podzolization due to the loess content of the upper layer even exceeding this the dominant loess content of an intercalated intermediate layer in threefold sequences may completely decouple pedogenesis from bedrock influence in all soil formation is largely influenced by the constellation of cover beds at any given site

the shedding of mesoscale anticyclonic eddies from the alaskan stream and westward transport of warm water abstract the south flowing waters of the kamchatka and oyashio currents and west flowing waters of the alaskan stream are key components of the western sub arctic pacific circulation we use ctd data argo buoys woce surface drifters and satellite derived sea level observations to investigate the structure and interannual changes in this system that arise from interactions among anticyclonic eddies and the mean flow variability in the temperature of the upstream oyashio and kamchatka currents is evident by warming in mesothermal layer in 1994 2005 compared to 1990 1991 a major fraction of the water in these currents is derived directly from the alaskan stream the stream also sheds large anticyclonic aleutian eddies averaging approximately 300 km in diameter with a volume transport significant in comparison with that of the kamchatka current itself these eddies enclose pools of relatively warm and saline water whose temperature is typically 4 c warmer and salinity is 0 4 greater than that of cold core kamchatka eddies in the same density range aleutian eddies drift at approximately 1 2 km d 1 and retain their distinctive warm and salty characteristics for at least 2 years selected westward pathways during 1990 2004 are identified if the shorter northern route is followed aleutian eddies remain close to the stream and persist sufficiently long to carry warm and saline water directly to the kamchatka current this was observed during 1994 1997 with substantial warming of the waters in the kamchatka current and upstream oyashio if the eddies take a more southern route they detach from the stream but can still contribute significant quantities of warm and saline water to the upstream oyashio as in 2004 2005 however the eddies following this southern route may dissipate before reaching the western boundary current region

the petrological significance of misorientations between grains misorientation analysis quantifies microstructural features in tectonites metamorphic and igneous rocks and allows hypotheses on their formation to be tested the misorientation between two lattices can be expressed by a rotation axis and rotation angle for lattices with symmetry it is conventional to take the minimum angle that enables one lattice to be rotated into the other for a group of lattice measurements two types of misorientation distribution can be calculated selecting random pairs of grains gives the random pair misorientation distribution selecting neighbouring pairs gives the neighbour pair misorientation distribution the forms of both distributions are visualised using histograms or cumulative frequency diagrams they are strongly influenced by any overall crystallographic preferred orientation and by intrinsic crystal symmetry in many rocks the random pair misorientation distribution and neighbour pair misorientation distribution are statistically significantly different quantified using the kolmogorov smirnov test differences between the random pair misorientation distribution and neighbour pair misorientation distribution imply that adjacent grains have physically interacted or are inherited from a precursor microstructure interactions include 1 reduction in surface energy by lattice alignment we show this may have occurred in garnet clusters in schist and olivine in a cumulate it is well known in metals and may be a common geological process 2 nucleation where those nuclei have influenced the orientation of adjacent nuclei 3 mechanical rotations of facetted grains in compacting crystal mushes so that faces become parallel 4 growth twinning inheritance includes 1 subgrain rotation recrystallisation in tectonites deforming by crystal plastic processes 2 mechanical and transformation related twinning 3 domainal microstructures e g where grains have formed from a few large original grains may give rise to spurious correlations when the orientation data cover more than one domain with this proviso misorientation analysis can be used to investigate many important microstructural processes

cryptic variations within chromitites of the upper critical zone northwestern bushveld complex the close association of platinum group elements with chromite in the upper critical zone calls for the appraisal of structures textures and composition of chromitites in the development of genetic models cryptic variations in successive chromitite layers of the ug 1 unit are consistent with fractionation of limited melt volumes individual chromitite bands within the composite ug 2 chromitite layer exhibit distinctive compositions but all display long range compositional trends with height superimposed on short range homogeneity accessory chromites are substantially different from massive chromitites in composition reaction with residual liquids and subsolidus reactions were significant recrystallization of chromitites was ubiquitous but the importance of in situ growth is shown by relict textures long range settling adcumulus growth or deposition from density currents are processes that find little support in the data presented

characteristics of mesoscale eddies in the kuroshio oyashio extension region detected from the distribution of the sea surface height anomaly abstract this study investigates the distribution of the sea surface height anomaly ssha with the aim of quantifying the characteristics of mesoscale eddies in the kuroshio oyashio extension region koer where intense mesoscale eddies are commonly observed during hydrographic surveys dense distributions of both anticyclonic eddies aes and cyclonic eddies ces are detected for the first time in koer with sufficient temporal and spatial coverage using the okubo weiss parameter without smoothing their contribution to the total ssha variance is estimated to be about 50 the zones of highest amplitudes are located north and south of the axis of the kuroshio extension ke for aes and ces which represent warm core and cold core rings respectively the areas extend poleward along the japan and kuril kamchatka trenches especially for aes eddies of both polarities and with moderate amplitudes are also recognized along the subarctic front saf eddies in areas north and south of the ke generally pro

recent variability in the pacific western subarctic boundary currents and sea of okhotsk abstract the objective of this research is to describe physical processes which are the cause of the recent variability of the pacific western subarctic waters rapid thermohaline changes have occurred within the oyashio and kamchatka current during the last decade this variability has included a warming of the kamchatka current warm intermediate layer but a cooling and freshening of the upper layer in the oyashio and sea of okhotsk the example presented here uses data obtained during the canada russia inpoc and woce projects as well as the new russian studies with high resolution station grid the possible physical mechanism that generated the upper layer freshening during the thermohaline transition is examined major components of the fresh water budget of the okhotsk sea are considered in order to describe the dramatic changes in salinity which have recently occurred in the pacific subarctic significant changes in precipitation and other fresh water inputs are demonstrated it is suggested that upper layer of the oyashio and kamchatka current became cooler and fresher because of the export of cold fresher waters from the bering and okhotsk seas these waters from the marginal seas have cooled the bottom of the halocline reducing evaporation and acting as a feedback that has kept the upper layer of the western subarctic boundary currents fresh it is also shown that the outflow of the cold sea of okhotsk water has changed its path during this recent thermohaline transition

the concept of the pleistocene periglacial cover beds in central europe a review in low mountain areas of central europe pleistocene periglacial conditions and relevant processes have led to the formation of cover beds in general holocene soils are not developed in bedrock but they have formed in periglacial cover beds their occurrence and characteristics control the spatial distribution of soils and thus periglacial sediments are a useful tool for soil mapping and soil survey the concept of periglacial cover beds distinguishes four main layers topmost upper middle and basal periglacial cover bed the upper and middle layers contain loess whereas the basal one consists entirely of bedrock the loess content causes an increase of site specific soil ecological quality in comparison to soils formed directly on bedrock the occurrence and characteristics of the cover beds is reviewed summarizing the present state of the art

global observations of large oceanic eddies 1 ten years of sea surface height ssh fields constructed from the merged topex poseidon t p and ers 1 2 altimeter datasets are analyzed to investigate mesoscale variability in the global ocean the higher resolution of the merged dataset reveals that more than 50 of the variability over much of the world ocean is accounted for by eddies with amplitudes of 5 25 cm and diameters of 100 200 km these eddies propagate nearly due west at approximately the phase speed of nondispersive baroclinic rossby waves with preferences for slight poleward and equatorward deflection of cyclonic and anticyclonic eddies respectively the vast majority of the eddies are found to be nonlinear

platinum group elements in sulphide minerals platinum group minerals and whole rocks of the merensky reef bushveld complex south africa implications for the formation of the reef the concentrations of platinum group elements pge co re au and ag have been determined in the base metal sulphide bms of a section of the merensky reef in addition we performed detailed image analysis of the platinum group minerals pgm the aims of the study were to establish 1 whether the bms are the principal host of these elements 2 whether individual elements preferentially partition into a specific bms 3 whether the concentration of the elements varies with stratigraphy or lithology 4 what is the proportion of pge hosted by pgm 5 whether the pgm and the pge found in bms could account for the complete pge budget of the whole rocks in all lithologies most of the pge 65 up to 85 are hosted by pgm essentially pt fe alloy pt pd sulphide pt pd bismuthotelluride lesser amounts of pge occur in solid solution within the bms in most cases the pgm occur at the contact between the bms and silicates or oxides or are included within the bms pentlandite is the principal bms host of all of the pge except pt and contains up to 600 ppm combined pge it is preferentially enriched in pd rh and co pyrrhotite contains rh os ir and ru but excludes both pt and pd chalcopyrite contains very little of the pge but does concentrate ag and cd platinum and au do not partition into any of the bms instead they occur in the form of pgm and electrum in the chromitite layers the whole rock concentrations of all the pge except pd are enriched by a factor of five relative to s ni cu and au this enrichment could be attributed to bms in these layers being richer in pge than the bms in the silicate layers however the pge content in the bms varies only slightly as a function of the stratigraphy the bms in the chromitites contain twice as much pge as the bms in the silicate rocks but this is not sufficient to explain the strong enrichment of pge in the chromitites in the light of our results we propose that the collection of the pge occurred in two steps in the chromitites some pgm formed before sulphide saturation during chromitite layer formation the remaining pge were collected by an immiscible sulphide liquid that percolated downward until it encountered the chromitite layers in the silicate rocks pge were collected by only the sulphide liquid

migration of the kuroshio extension in the northwest pacific since the last glacial maximum abstract the 18o values of planktic and benthic foraminifera and faunal assemblage of planktic foraminifera were investigated at a northwest pacific site 32 16 n 158 13 e 2514 m water depth to understand the oceanographic changes in the kuroshio extension ke region over the past 23 kyr the 18o differences between species and the relative abundances of the dominant planktic foraminiferal species have not changed greatly over the study period suggesting that the subarctic boundary and the subarctic subtropical transition zone have remained north of study site while the study site itself has been under the influence of ke nevertheless increased abundances of foraminiferal taxa that populated the subarctic subtropical transition zone during the last glacial maximum lgm indicate the input of transition zone water through the ke manifest as meandering cold core ring eddies generated along the ke since this unstable surface environment is most pronounced along the main axis of the ke it could have been induced by the southward displacement of the ke main axis to the vicinity of the study site in tandem with the overall southward displacement of the kuroshio oyashio extension system during the lgm the input of transition zone water mass has also increased during the deglacial northern hemisphere cold intervals i e heinrich stadial 1 and the younger dryas suggesting that the strengthened surface wind system regulated the surface ocean condition this demonstrates that the northern high latitudes are the dominant control on post glacial oceanographic changes in the northwest pacific ke region

noble metal enrichment processes in the merensky reef bushveld complex we have analysed sulphides silicates and chromites of the merensky introduction reef for platinum group elements pges re and au using laser the enrichment of noble metals in layered gabbroic ablation inductively coupled plasma mass spectrometry and synthetic intrusions to form stratiform merensky type ore horizons pyrrhotite standards annealed with known quantities of noble metals is an extremely efficient yet poorly understood process os ir and ru reside in solid solution in pyrrhotite and pentlandite metal enrichment must be related to the formation of rh and part of the reef s pd in pentlandite whereas pt au re magmatic layering as the ore horizons form an integral and some pd form discrete phases olivine and chromite often part of the magmatic stratigraphies of their host insuspected to carry os ir and ru are pge free all phases analysed trusions metal concentration is also related to the prescontain noble metals as discrete micro inclusions with diameters ence of magmatic sulphides because the noble metals are either dissolved in base metal sulphides or occur as typically 100 nm inclusions in sulphides commonly have the discrete noble mineral phases intergrown with sulphides element combinations os ir pt and pt pd au inclusions in vermaak hendriks 1976 ballhaus ryan 1995 olivine and chromite are dominated by pt au pd few inclusion ballhaus ulmer 1995 spectra can be related to discrete noble metal phases and few there is considerable controversy as to where the inclusions have formed by sub solidus exsolution rather some metals came from and how metal enrichment worked pge inclusions notably those in olivine and chromite are earlyfor a stratiform platinum group element pge deposit magmatic nuggets trapped when their host phases crystallized we inside the magmatic stratigraphy of a layered intrusion suggest that the silicate melt layer that preceded the merensky reef there are two possibilities either the metals were derived was pge oversaturated at early cumulus times experiments from the melt column above the ore horizon or they came combined with available sulphide silicate partition coefficients sugfrom the magma equivalent to the cumulate package gest that a silicate melt in equilibrium with a sulphide melt underlying the ore owing to the large density contrast containing the pge spectrum of the merensky ore would indeed be between silicate and sulphide melt a popular view is that oversaturated with respect to the least soluble noble metals sulphide the metals were enriched by gravitational settling of melt apparently played little role in enriching the noble metals in sulphide melt i e out of the magma column above the the merensky reef rather its role was to immobilize a pre existing ore campbell et al 1983 barnes naldrett 1985 in situ stratiform pge anomaly in the liquid stratified magma naldrett et al 1987 on the other hand it is well chamber established that gravitational crystal settling plays little role in producing magmatic layering and magmatic stratigraphies mcbirney noyes 1979 morse 1986 campbell 1987 and this cannot remain without consequence for stratiform noble metal deposits a third alternative is noble metal enrichment by late

annual and interannual variability in the kuroshio current system abstract individual seasonal 300 m temperature maps were constructed over the kuroshio current system from 130 e to 170 w for a 4 year period from summer 1976 through spring 1980 using transpac xbt data and jodc temperature depth data quasi stationary meanders in the kuroshic current system occurred at 137 c i e kuroshio meander at 144 e and 150 e i e lee wave meanders and near 160 e i e meander over the shatsky rise a composite of the paths of the kuroshio i e the 12 c isotherm from the individual seasonal maps and the total variance map finds nodes i e minima and anti nodes i e maxima of variability to have existed along the mean kuroshio path the anti nodes coincided with the location of the quasi stationary meanders the nodes in between zonal propagation of temperature anomalies accounted for 20 30 of the total interannual variance these temperature anomalies propagated eastward at 0 5 1 5 cm s 1 in the region 140 155 e and westward at 1 to 2 cm s 1 in the re

vortices of the mediterranean sea an altimetric perspective the presence of coherent vortices makes observed mesoscale fields of the ocean resemble twodimensional turbulence using this analogy a common definition of a coherent structure has been used to study the statistical properties of mediterranean sea vortices observed by satellite altimeters over a 7 yr period a vortex has been defined as the simply connected region with values of the okubo weiss parameter w 0 2w where w is the spatial standard deviation of w and the same sign of vorticity this definition is shown to be appropriate to detect and characterize statistically properties such as size mean kinetic energy and amplitude of vortices in the mediterranean basin from sea level anomaly maps corresponding to the period from october 1992 to october 1999 the distribution of such properties for the mediterranean vortices suggests a heuristic criterion to extract and select very coherent and long lived vortices from the whole set of structures identified in altimetric maps such coherent vortices appear to be selected for amplitudes greater than 2w where the amplitude has been defined in terms of the okubo weiss parameter rather than vorticity and strongly correspond to those reported from observations with independent data systematic locating and tracking of such vortices provide for the first time a general picture of their preferential paths in the mediterranean basin which are characterized by complex but rather well defined patterns

origin of the pegmatitic pyroxenite in the merensky unit bushveld complex south africa the genesis of the pegmatitic pyroxenite that often forms the base of the merensky unit in the bushveld complex is re examined large 1 cm orthopyroxene grains contain tricuspidate inclusions of plagioclase and chains and rings of chromite grains which are interpreted to have grown by reaction between small primary orthopyroxene grains and superheated liquid this superheated liquid may have been an added magma or be due to a pressure reduction as a result of lateral expansion of the chamber there would then have been a period of non accumulation of grains permitting prolonged interaction with the crystal mush at the crystal liquid interface crystal ageing and grain enlargement of original orthopyroxene grains would ensue only after the pegmatitic pyroxenite had developed did another layer of chromite and pyroxenite with normal grain size accumulate above it immiscible sulphide liquids formed with the second pyroxenite but percolated down as a result of their density contrast even as far as the footwall anorthosite in some cases whole rock abundances of incompatible trace elements in the pegmatitic pyroxenite are comparable with or lower than those of the overlying pyroxenite and so there is no evidence for addition and or trapping of large proportions of interstitial liquid or of an incompatible element enriched liquid or fluid in the production of the pegmatitic rock because of the coarse grained nature of the rock modal analysis especially for minor minerals is unreliable annealing has destroyed primary textures such that petrographic studies should not be used in isolation to distinguish cumulus and intercumulus components geochemical data suggest that the merensky pyroxenite both pegmatitic and non pegmatitic typically consists of about 70 80 cumulus orthopyroxene and 10 20 cumulus plagioclase with a further 10 of intercumulus minerals and could be considered to be a heteradcumulate

quasi decadal variation in intensity of the western part of the winter subarctic sst front in the western north pacific the influence of kuroshio extension path state abstractvariations of the subarctic front saf which is extracted as a strong sea surface temperature sst gradient in the longitudinal band of 146 152 e were investigated over 30 winters january march from 1982 to 2011 using high spatial resolution satellite derived sst dataset and hydrographic observations the saf had little meridional movement in this longitudinal band lying between 40 and 41 n throughout the analysis period the saf intensity had a dominant quasi decadal time scale about 8 yr its intensity in the strong phase was up to about 50 higher than in the weak phase the saf intensity strongly reflected upper ocean conditions in the kuroshio oyashio confluence koc region just south of the saf in the strong saf phase large positive anomalies in both temperature and salinity were found in the koc region not only at the sea surface but also below 300 m and the water properties in the koc region were those of the kuroshio water the warm salty water in the koc region was supp

origin of podiform chromite deposits by magma mingling abstract i have oversaturated the immiscible system sio2 al2o3 feo k2o with fecr2o4 to study the fractionation of chromite between conjugate siliceous and fayalitic melts although both melts are oversaturated with chromite chromite only nucleates in the fayalite rich melt where the crystal melt interfacial energy sl is lowest in less than three days at 1150 c all excess chromium in the bulk composition is concentrated as cumulus chromite in the fayalitic melt pools producing nodular cumulate textures as observed in podiform chromite ore when these results are applied to the lithospheric mantle podiform chromite deposits may form when droplets of olivine normative high pressure low viscosity melt mingle with siliceous low pressure more viscous melt in shallow magma conduits it is inferred from the experimental analogue that chromite only nucleates in the melt where sl is lowest which in the mantle would be the high pressure melt the low pressure melt only serves as the diffusive chromium reservoir the richest chromite ores form when the volume ratio of the melt nucleating chromite is small relative to the ambient melt

evolution and modulation of a poleward propagating anticyclonic eddy along the japan and kuril kamchatka trenches to investigate the relationships between the movement of an eddy and its interior structure and water properties four profiling floats were deployed in an anticyclonic eddy in the western north pacific in 2013 april october daily float profiles showed rapid changes in temperature and salinity corresponding to strong interactions between eddies north of the subtropical kuroshio extension after the first interaction with a warm core eddy in april the isolation of the winter mixed layer from the surface was observed forming a subsurface remnant layer another interaction with a cold fresh eddy at middepths in may resulted in the formation of a multilayer structure the eddy then moved poleward along the japan and kuril kamchatka trenches indicating changes in its propagation pattern coupled to its interior structure the eddy then moved northward june july stalled july august and moved eastward august october in addition to a general declining trend the properties of the warm saline core changed over a short time period coinciding with changes in propagation a density anomaly at middepths of the eddy changed location during the stalled period however denser waters were continuously observed in the southeast part of the eddy during its northward and eastward movement this unidirectional density anomaly pattern was consistent with the structure of the poleward propagating eddy which interacted with the western topographic boundary meridional exchanges of heat and material were potentially elevated by the eddy s advection and movement as well as by water modifications in the eddy associated with exchanges along its perimeter

petrogenesis of the merensky reef in the rustenburg section of the bushveld complex a petrogenetic model for the merensky reef in the rustenburg section of the bushveld complex has been developed based on detailed field and petrographic observations and electron microprobe data the model maintains that the reef formed by reaction of hydrous melt and a partially molten cumulate assemblage the model is devised to account for several key observations 1 although the dominant rock type in the rusterburg sections is pegmatoidal feldspathic pyroxenite there is a continous range of reef lithology from pyroxenite to pegmatoidal harzburgite and dunite and small amounts of olivine are present in nearly all pegmatoids 2 the pegmatoid is usually bounded above and below by chromitite seams and the basal chromitite separated from underlying norite by a centimeter thick layer of anorthosite the thicknesses of the two layers exhibit a well defined positive correlation 3 inclusion of pyroxenite identical to the hanging wall and of leuconorite identical to the footwall are present in the pegmatoid the leuconorite inclusions are surrounded by thin anorthosite and chromitite layers in the same sequence as that at the base of the reef 4 chromite in seams adjacent to plagioclase rich rocks is characterized by higher mg mg fe and al r3 and lower cr r3 than that in seams adjacent to pyroxene rich rocks similar variations in mineral compositions are observed across individual chromitite seams where the underlying and overlying rock types differ the chromite compositional variations cannot be rationalized in terms of either fractional crystallization or reequilibration with surrounding silicates it is proposed that the present reef was originally a melt rich horizon in norite immediately overlain by relatively crystallized pyroxenite magmatic vapor generated by crystallization of intercumulus melt migrated upward through fractures in the cumulate pile below the protoreef the melt rich protoreef became hydrated because fractures were unable to propagate through it and because the melt itself was water undersaturated hydration of the intercumulus melt was accompanied by melting and the hydration melting front migrated downward into the footwall and upward into the hanging wall in the footwall melting resulted first in the dissolution of orthopyroxene and then of plagioclase with continued hydration chromite was stabilized as melt alumina content increased the regular variations in chromite compositions reflect the original gradients in melt composition at the hydration front the stratigraphic sequence downward through the base of the reef or pegmatoid melt chromitite anorthosite norite represents the sequence of stable mineral assemblages across the hydration melting front the sequence is shown to be consistent with knowledge gained from experiments on melting of hydrous mafic systems at crustal pressures with cooling the hydrated mixture from partial melting of norite footwall and more mafic hanging wall crystallized in the sequence chromite olivine pyroxene plagioclase with peritectic loss of some olivine calculations of mass balance indicate that a significant proportion of the melt was lost from the melt rich horizon variations in the development of the pegmatoid and associated lithologies and amount of modal olivine in the pegmatoids along the strike of the merensky reef resulted because the processes of hydration melting and melt loss operated to varying extents

sulfide and platinum mineralization in the merensky reef evidence from hydrous silicates and fluid inclusions the base metal sulfides of the merensky reef are associated with hydrous silicates and intense deuteric hydrous alteration of cumulus and postcumulus silicates biotite and phlogopite crystallized in the vicinity of sulfides from a volatile enriched highly fractionated intercumulus melt amphibole chlorite and talc are later alteration phases of cumulus pyroxene and intercumulus plagioclase biotite is often accompanied by zircon rutile and quartz accessory quartz hosts a complex suite of h2o nacl cacl2 co2 ch4 fluid inclusions which have thus far not been described from the merensky reef the earliest fluid inclusion compositions are nacl h2o with less than 10 vol water co2 coexisting with a halite daughter crystal and brine and polyphase inclusions with up to six daughter and accidental phases and high contents of divalent cations the maximum trapping temperature is around 730 c at 4 to 5 kb pressure later inclusion generations are h2o nacl co2 h2o and pure co2 and ch4 the presence of cl rich fluids during the intercumulus stage of the crystallizing merensky reef is directly related to the mode of sulfide precipitation prior to sulfide unmixing in a hydrous magma sulfur is likely to be present as h2s sulfur saturation causes reaction of h2s with oxides of the silicate melt to form a sulfide melt plus water during reaction the magma is enriched in water until a separate fluid unmixes it carries all compounds with high fluid melt partition coefficients as well as metals capable of forming oh and cl complexes precious metals are assumed to have fractionated into the cl rich fluid as cl complexes rather than being dissolved in the sulfide melt during the cooling evolution of the fluid the precious elements precipitate around the periphery of sulfide melt droplets the model proposed explains the distribution pattern of platinum group minerals in the merensky reef better than any orthomagmatic mineralization concept offered so far

periglacial cover beds and soils in landslide areas of sw germany abstract at the slopes of the jurassic cuesta scarp in sw germany pedological and mineralogical investigations were carried out in landslide areas so far it is possible to distinguish two well defined landslide areas one of them belonging to the pleistocene the other one characterised by holocene movements in general the distribution of soils and sediments is strongly linked to the age of landslide deposits in pleistocene landslide areas the parent material of the studied soils is formed by periglacial cover beds of late pleistocene age consisting of jurassic aeolian and volcanic components the upper periglacial cover bed was recognised as the most important marker horizon in the studied slope areas there the existence of minerals originating from the eruption of the laacher see volcano dated to 12 900 yr bp could be demonstrated for the first time most of the pleistocene landforms are characterised by well developed soils like clayic and vertic cambisols whereas relic soils exclusively occur in the oldest parts of landslide deposits landslide areas affected by holocene slope processes do not exhibit periglacial layers as mass movements removed periglacial sediments and former soils extensively as a consequence the parent material is different from those of pleistocene landslide areas therefore sediments in these areas are characterised by jurassic components and only initial soils are present

decadal variation in winter mixed layer depth south of the kuroshio extension and its influence on winter mixed layer temperature abstractthe long term behavior of the wintertime mixed layer depth mld and mixed layer temperature mlt are investigated in a region south of the kuroshio extension ke 30 37 n 141 155 e an area of the north pacific subtropical gyre where the deepest mld occurs using historical temperature profiles of 1968 2014 both the mld and mlt in march have low frequency variations which show significant decadal 10 yr variations after the late 1980s observational data and simulation outputs from a one dimensional turbulent closure model reveal that surface cooling is the main control on winter mld in the late 1970s and 1980s whereas there is a change in the strength of subsurface stratification is the main control after 1990 in the latter period a weak strong subsurface stratification is caused by a straight path convoluted path of the ke and by a deepening shallowing of the main thermocline depth due to oceanic rossby waves formed as a result of positive negative anomalies of wind stress

geochemical evidence for african dust and volcanic ash inputs to terra rossa soils on carbonate reef terraces northern jamaica west indies abstract the origin of red or reddish brown clay rich terra rossa soils on limestone has been debated for decades a traditional qualitative explanation for their formation has been the accumulation of insoluble residues as the limestone is progressively dissolved over time however this mode of formation often requires unrealistic or impossible amounts of carbonate dissolution therefore where this mechanism is not viable and where local fluvial or colluvial inputs can be ruled out an external source or sources must be involved in soil formation on the north coast of the caribbean island of jamaica we studied a sequence of terra rossa soils developed on emergent limestones thought to be of quaternary age the soils become progressively thicker redder more fe and al rich and si poor with elevation furthermore although kaolinite is found in all the soils the highest and oldest soils also contain boehmite major and trace element geochemistry shows that the host limestones and local igneous rocks are not likely source materials for the soils other trace elements including the rare earth elements ree show that tephra from central american volcanoes is not a likely source either however trace element geochemistry shows that airborne dust from africa plus tephra from the lesser antilles island arc are possible source materials for the clay rich soils a third as yet unidentified source may also contribute to the soils we hypothesize that older more chemically mature jamaican bauxites may have had a similar origin the results add to the growing body of evidence of the importance of multiple parent materials including far traveled dust to soil genesis

eddies advected by time dependent sverdrup circulation in the western boundary of the subarctic north pacific 1 it has been reported that several eddies frequently exist along the kuril kamchatka trench k k trench hereafter the western boundary of the subarctic north pacific lagged correlation maps of the altimeter derived sea level anomalies slas along the trench indicate that the southern eddies on the whole move northeastward along the k k trench and the northern eddies on the other hand move southwestward by tracking each anticyclonic eddy its propagating velocity along the trench is calculated the time series of the tracked 7 eddies shows similar seasonal variation to those of the first empirical orthogonal function eof of the sla maps and to those of the sverdrup transport at 40 n in addition when more than two eddies remotely exist in the studied area they show coherent moving patterns these results suggest that the eddies in the western boundary region of the subarctic north pacific are advected by the time dependent wind driven current

saprolite soils and sediments in the rhenish massif as records of climate and landscape history abstract the rhenish massif at the western boundary of germany consists predominantly of devonian slates and siltstones which over large areas have been altered to saprolite the distribution and characteristics of saprolites pleistocene periglacial slope deposits ppsd holocene colluvium and soils were investigated along a 2 5 m deep gas pipeline ditch in 20 sections with an overall length of 19 km the results are used for landscape history reconstruction under warm humid conditions of the upper mesozoic and lower tertiary intensive weathering led to formation of a planation surface covered by thick saprolites and kaolinitic soils during pleistocene glaciations the area experienced periglacial conditions that resulted in erosion of the soils and parts of the saprolites several layers of ppsd developed during the holocene no significant slope processes occurred until human deforestation led to accelerated hillslope erosion as a result today the ppsd are partly eroded or covered by holocene colluvium in many places the sediment distribution follows distinct rules generally the sediment thickness increases downslope concave slope sections show a substantial increase in thickness and number of preserved sediment layers the soils developed in ppsd on saprolite are primarily planosols while cambisols and luvisols predominate in ppsd on fresh rock

sensitivity of frost weathering and aeolian deposition during genesis of late quaternary periglacial slope covers on calcareous rocks of a muschelkalk landscape eastern thuringian basin germany abstract pleistocene periglacial loose rock covers on calcareous rocks of mesozoic muschelkalk contain sediments which are derived from loess deposition frost weathering as well as limestone dissolution processes distinct sediments form periglacial slope deposits psd with a layered vertical structure consisting of basal layers bl intermediate layers il and upper layer ul the basal layer has in part a notably more complex structure than on siliceous or quartz bedrock the lithological and petrological properties of calcareous rock types are reflected by remarkably different structure thickness and clast properties of frost shattered debris within the investigated muschelkalk landscape as well as in chemical weathering rates within the debris furthermore we could detect a high variability in the thickness and distribution of aeolian matter too we assume that the deposition of loess sediments might be sensitive to both properties and patterns of debris cover and to the amount of pre existing braunlehm that resulted from limestone dissolution processes soil moisture conditions and vegetation cover might have been as crucial factors for loess distribution as luff lee effects of the regional wind system or karst surface morphology considering the ecological consequences implied by the structure and heterogeneity of periglacial loose rock cover limestone landscapes in general seem to be vulnerable to degradation processes particularly sites of shallow sediment depth or rich in rock debris might be rapidly degraded by soil erosion have low protection potential against groundwater pollution and might have a high sensitivity towards climatic impacts like water shortage and drought stress

currents associated with the quasi stationary jet separated from the kuroshio extension abstractthe hydrographic structure of a quasi stationary jet separated from the kuroshio extension a phenomenon that possibly leads to deepening of the winter mixed layer is revealed via intensive observations using a conductivity temperature depth profiler and a ship mounted acoustic doppler current profiler adcp carried out in september 2009 data collected from profiling floats set to drift isopycnal layers and time series of sea surface buoys and satellite altimeters were also analyzed to understand the continuity water characteristics and time variation of the jet although the flow field was complex due to disturbances such as energetic eddies the jet transported subtropical water to the downstream northeastern observation region in a layer shallower than 400 dbar and its highest velocity was concentrated in the mid and deep layers 0 30 m s 1 at the sea surface and 0 05 m s 1 at 800 m depth the velocity axes of the jet detected from the satellite data corresponded to those detected th

the instabilities and multiscale energetics underlying the mean interannual eddy interactions in the kuroshio extension region abstractusing a recently developed energetics diagnostic methodology namely the localized multiscale energy and vorticity analysis ms eva this study investigates the intricate nonlinear mutual interactions among the decadally modulating mean flow the interannual fluctuations and the transient eddies in the kuroshio extension region it is found that the mean kinetic energy maximizes immediately east of the izu ogasawara ridge while the transient eddy kinetic energy does not peak until 400 km away downstream the interannual variabilities which are dominated by a jet trapped rossby wave mode provide an energy reservoir comparable to the other counterparts in the upstream strong localized barotropic and baroclinic transfers from the mean flow to the eddies are observed whereas those from the interannual variabilities are not significant besides fueling the eddies the unstable mean jet also releases energy to the interannual scale processes between 144 and 154 e both transfers from the mean

the ug2 merensky reef interval of the bushveld complex northwest of pretoria northwest of pretoria the ug2 merensky reef interval overlies a critical zone lower zone sequence that contains numerous large blocks of floor material nevertheless individual layers can be correlated with equivalent units at crocodile river mine the rustenburg impala union and amandelbult sections concentrations of platinum group elements in two borehole intersections of the ug2 chromitite are 4 ppm over 1 2 m and 2 4 ppm over 2 2 m therefore bulk pge levels appear to be only moderately lower than those at western platinum mine this renders models explaining pge enrichment by upward percolating melt or fluids problematic the merensky reef although containing sulphides is only weakly mineralized with pge 0 6 ppm the ug2 pyroxenite is separated from the ug2 chromitite by a 15 m noritic layer the introduction of feldspathic cumulates between two units that elsewhere directly overly each other may be explained by the more evolved composition of resident magma in those parts of the chamber distally located with regard to a major feeder zone at union section it also suggests that the ug2 unit is a multiple rather than a single cyclic unit