the evolution of oceanic and atmospheric anomalies in the northeast pacific during the el nino and la nina events of 1995 2001 abstract from late 1995 through early 2001 three major interannual climate events occurred in the tropical pacific the 1995 97 la nina ln 1997 98 el nino en and 1998 2001 ln we analyze atmospheric and upper oceanic anomalies in the northeast pacific nep during these events and compare them to anomalies both elsewhere in the north and tropical pacific and to typical en and ln anomaly patterns the atmospheric and oceanic anomalies varied strongly on intraseasonal and interannual scales during the 1995 97 ln and 1997 98 en the northeast pacific was dominated by negative slp and cyclonic wind anomalies and by upper ocean temperature and sea surface height ssh anomalies the latter were positive along the north american west coast and in the nep thermal anomaly pool between hawaii vancouver island and baja california and negative in the central north pacific this atmospheric oceanic anomaly pattern is typical of en an eastward shift in the atmospheric teleconnection from east asia created en like anomalies in the nep during the 1995 97 ln well before the 1997 98 en had begun the persistence of negative sea level pressure slp and cyclonic wind anomalies in the nep during the 1997 98 en intensified pre existing upper oceanic anomalies atmospheric anomalies were shifted eastward during late 1996 early 1998 leading to a similar onshore shift of oceanic anomalies this produced exceptionally strong positive upper ocean temperature and ssh anomalies along the west coast during the 1997 98 en and explains the unusual coastal occurrences of several species of large pelagic warm water fishes the growth and eastward shift of these pre existing anomalies does not appear to have been linked to tropical pacific en anomalies until late 1997 when a clear atmospheric teleconnection between the two regions developed prior to this remote atmospheric impacts on the nep were primarily from east asia as the 1998 2001 ln developed nep anomalies began reversing toward the typical ln pattern this led to predominantly negative slp and cyclonic wind anomalies in the nep and upper ocean temperature and ssh anomalies that were mainly negative along the west coast and positive in the central north pacific the persistence of these anomalies into mid 2001 and a number of concurrent biological changes in the nep suggest that a decadal climate shift may have occurred in late 1998 during 1995 2001 nep oceanic anomalies tracked the overlying atmospheric anomalies as indicated by the maintenance of a characteristic spatial relationship between these anomalies in particular wind stress curl and ssh anomalies in the nep maintained an inverse relationship that strengthened and shifted eastward toward the west coast during late 1996 early 1998 this consistent relationship indicates that anomalous ekman transport driven by regional atmospheric forcing was an important contributor to temperature and ssh anomalies in the nep and ccs during the 1997 98 en other studies have shown that coastal propagations originating from the tropical pacific also may have contributed to coastal nep anomalies during this en our results indicate that at least some of this coastal anomaly signal may have been generated by regional atmospheric forcing within the nep

late quaternary climate variability and vegetation response in ziro lake basin eastern himalaya a multiproxy approach abstract pollen phytolith and stable carbon isotopic records provide new insights into the palaeoenvironmental and palaeoclimatic changes in ziro lake basin sub himalayan arunachal pradesh india since pre lgm time phytoliths record a minor change in grass woodland cover and appear to be more sensitive than pollen grains to climate fluctuations both pollen and non pollen palynomorph data suggest prevalence of a dense c3 species dominated moist semi evergreen forest in the area until the lgm which shows conformity with 13c data the phytolith assemblage indicates an alteration in forest cover with expansion of c4 grasses during the lgm the study further indicates a climatic amelioration with intensification of south west monsoon during 10 2 3 8 ka and an expansion of forest cover after 3 8 ka there was a rising trend of dryness shrinkage in forest cover and a slight increase in c4 species while c3 plants dominated ecosystem variability also points towards a hydrological transformation in the area since pre lgm time application of coexistence approach on pollen data reveals that prior to the lgm the mean annual temperature and mean annual precipitation were approximately 19 3 0 001 c and 1925 15 mm respectively between 10 2 and 3 8 ka mat was about 19 4 0 5 c while map was 1901 41 3 mm between 3 8 and 1 2 ka and onwards a slight increase in mat 0 3c was observed with further decrease in map to 1861 33 4 mm during pre and post lgm times mat was more or less similar in the ziro lake basin which increased gradually after 3 8 ka and was 1 2 c higher than today prior to the lgm map was higher than the present day by 94 mm between 10 2 and 3 8 ka by 70 mm and since 3 8 ka onwards by 30 mm showing a tendency of gradual decline suggesting a consequent increase in dryness

rare earth element mobility during prograde granulite facies metamorphism significance of fluorine mafic gneisses occur as lenses or thin layers in spatial association with tonalitic leucosomes in a granulite zone of the quetico subprovince of the superior province ontario canada and exhibit concentric zoning with a biotite rich margin orthopyroxene rich outer zone clinopyroxene rich central zone and occasionally patches of relict amphibolites within the clinopyroxene rich zone the granulites biotite orthopyroxene and clinopyroxene rich zones in the mafic gneisses are characterized by significant amounts of rare earth element ree bearing fluorapatite 1 10 vol and other ree rich minerals allanite monazite and zircon fluorapatite shows an increase in modal abundance from the biotite and orthopyroxene rich zones to the clinopyroxene rich zone but is rare in the relict amphibolites textural evidence and element partitioning indicate that fluorapatite and other ree rich minerals was part of the peak metamorphic assemblages whole rock geochemical analyses confirm that the granulites in the mafic gneisses contain anomalously high contents of ree and high field strength elements hfse whereas the relict amphibolites are geochemically typical of tholeiitic basalts mass balance calculations reveal that ree and hfse were introduced into the mafic gneisses during the prograde granulite facies metamorphism pointing to ree mobility under granulite facies metamorphic conditions the presence of high f contents in the ree rich minerals and their associated minerals e g biotite and hornblende suggests that ree and hfse may have been transported as fluoride complexes during the granulite facies metamorphism this conclusion is supported by previously published results of hydrothermal experiments on the partitioning of ree between fluorapatite and f rich fluids at 700 c and 2 kbar

phytoliths indicators of grassland dynamics during the late holocene in intertropical africa abstract the reconstruction of african tropical grassland history during the late holocene can be carried out using phytolith analysis fossil phytolith assemblages from lake guiers in the sahelian region of senegal and from lake sinnda in the guineo congolian region of congo were investigated the results are interpreted on the basis of modern phytolith assemblages from the same regions and compared to pollen data previously obtained tall or short grass associations are discriminated by their phytolith index iph saddle cross dumbel saddle while the density of shrubs and trees is indicated by relative proportions of the dicotyledon phytoliths the phytolith data emphasize that in the guineo congolian region around lake sinnda the driest phase of the late holocene occurred between 4000 and 1200 yr b p commencing with the opening of the dense forest and its replacement by a short grass savanna from ca 1000 yr b p wetter climatic conditions developed as represented by the setting up of a tall grass savanna woodland the modern shrub and tall grass savanna was developed ca 700 yr b p in the sahelian region around lake guiers the driest phase occurred after about 2000 yr b p and has not been followed by moister conditions a tall grass savanna woodland was gradually replaced by a shrub and short grass savanna which still occurs a short period of development of swampy vegetation which can be related to a lake level change interrupted the semi arid adaptation of the vegetation between about 2000 yr b p and the present

comment on the paper in quaternary international methodological concerns for analysis of phytolith assemblages does count size matter c a e stromberg for the last three decades fossil phytolith assemblages from soils buried soils and lake sediments have been used in addition to other vegetation indicators to reconstruct paleovegetation changes however in the objective of strengthening further accuracy for these reconstructions and in addition to comparison with reference plant collections recent effort has been made to provide quantitative relationships between modern phytolith assemblages from soils vegetation and bio climatic parameters e g alexandre et al 1997 fredlund and tieszen 1997 bremond et al 2004 2005a b 2008 blinnikov 2005 albert et al 2006 lu et al 2006 barboni et al 2007 along this line stromberg quaternary international this volume presented a paper entitled methodological concerns for analysis of phytolith assemblages does count size matter articulated on 1 calculation of confidence intervals related to count size and 2 investigation on how addition of these confidence intervals may affect vegetation interpretations the first point is a relevant contribution for increasing accuracy of phytolith data we comment here on the second point for the purpose of her demonstration the author used published modern phytolith data from west africa bremond et al 2005a b for which she misinterpreted the vegetation significance the phytolith index d p was first presented by alexandre et al 1997 and later further defined by bremond et al 2005a as the ratio of ligneous dicotyledon phytolith type globular granulate characteristic of trees in tropical areas of low elevation over the sum

interannual westward propagating baroclinic long wave activity on line p in the eastern midlatitude north pacific abstract for the period 1959 81 quasi zonal hydrographic sections have been made between the southern coast of vancouver island 49 n 126 w and ocean station p 50 n 145 w approximately every two months along this section called line p hydrographic std stations were repeated at nearly the same locations approximately 2 of longitude apart and at closer intervals near the coast as such 13 stations in all were made nearly every two months over the 23 year period thus the line p dataset has particular value in verifying the existence of interannual baroclinic long waves near 50 n in previous studies white kang and magaard and white and saur had found evidence of annual and interannual baroclinic long wave activity in the eastern midlatitude north pacific over the range 20 40 n but earlier attempts could not discover these westward traveling waves along line p in this study both spectral analysis and complex empirical orthogonal function analysis are used to do just that concentrating u

contributions of wind forcing waves and surface heating to sea surface height observations in the pacific ocean the dominant processes affecting sea surface height ssh variability observed by the topex poseidon altimeter vary regionally in the pacific baroclinic rossby waves equatorially trapped kelvin waves steric response to seasonal heating and the response to wind stress curl forcing are all important the steric response to surface heating dominates seasonal ssh variability in the subpolar gyre and the eastern subtropical gyre south of the kuroshio extension and south of 20 n in the eastern pacific the dominant contribution to ssh is from near annual period rossby waves to quantify the wave energy observed ssh was assimilated into a kinematic model of westward propagating waves these waves account for 70 of ssh variance between 10 s and 10 n but only 30 between 10 n and 30 n although wave energy in the eastern pacific is correlated with ssh anomalies at the equator the much larger wave energy in the western pacific is correlated with wind stress curl suggesting that the rossby waves there are locally forced in addition to these planetary waves the ocean response to wind forcing via ekman pumping is observed in several places specifically in the north equatorial current a quasi steady topographic sverdrup balance is detectable over most of the north pacific at latitudes as low as 10 15 n as well as in the south pacific where it is seen north of 50 s the decomposition of the ssh signal into propagating waves an ekman pumping response and sverdrup transport is consistent with the results from an isopycnal numerical model

rossby waves and the variability of the north pacific current during 2002 03 abstracta numerical model the parallel ocean program pop with 0 25 horizontal spatial resolution and 28 vertical levels is used to simulate the circulation of the north pacific ocean for the time period 1960 2006 spectral nudging is used so that model drift of the mean state over the 46 yr time period of the simulation is prevented while allowing for the prognostic evolution of the circulation at time scales that are not nudged the simulation successfully reproduces a southward shift in the north pacific current in 2002 03 as calculated from scalar observations it is suggested that this calculated shift may not be solely due to meridional current drift but also a consequence of the shifting intensity of two eastward moving current bands separated by 300 500 km a distance consistent with the rhines scale the scale at which the 2d turbulence cascade tends to be arrested which implies an influence from rossby waves that are heavily affected by nonlinearities the simulation suggests that the nort

enrichment of trace elements in garnet amphibolites from a paleo subduction zone catalina schist southern california the abundance p t stability solubility and element partitioning behavior of minerals such as rutile garnet sphene apatite zircon zoisite and allanite are critical variables in models for mass transfer from the slab to the mantle wedge in deep regions of subduction zones the influence of these minerals on the composition of subduction related magmas has been inferred and disputed from inverse modelling of the geochemistry of island arc basalt or by experiment although direct samples of the dehydration partial melting region of a mature subduction zone have not been reported from subduction complexes garnet amphibolites from melanges of circumpacific and caribbean blueschist terranes reflect high t 600 c conditions in shallower regions such rocks record geochemical processes that affected deep seated high t portions of paleo subduction zones in the catalina schist a subduction zone metamorphic terrane of southern california metasomatized and migmatitic garnet amphibolites occur as blocks in a matrix of meta ultramafic rocks this mafic and ultramafic complex may represent either slab derived material accreted to the mantle wedge of a nascent subduction zone or a portion of a shear zone closely related to the slab mantle wedge contact or both the trace element geochemistry of the complex and the distribution of trace elements among the minerals of garnet amphibolites were studied by inaa xrf electron microprobe and sem in order of increasing alteration from a probable metabasalt protolith three common types of garnet amphibolite blocks in the catalina schist are 1 non migmatitic clinopyroxene bearing blocks which are compositionally similar to morb that has lost an albite component 2 garnet amphibolite blocks which have rinds that reflect local interaction between metabasite metaperidotite and fluid and 3 migmatites that are extremely enriched in th hfse lree and other trace elements these trace element enrichments are mineralogically controlled by rutile garnet sphene apatite zircon zoisite and allanite alkali and alkaline earth elements are much less enriched in the solid assemblage and thus appear to be decoupled from the other elements in the inferred metasomatic process es the compositions of migmatitic garnet amphibolite blocks seem to complement that of average island arc tholeiite trace element metasomatism reflects fluid solid rather than melt solid interaction the metasomatic effects indicate that h2o rich fluid perhaps with a significant component of na al silicate and alkalis carried th u sr ree and hfse fractionations of lree in migmatites resemble those of migmatitic metasedimentary rocks underlying the mafic and ultramafic complex exotic lree deposited in allanite in migmatites could have been derived from fluids in equilibrium with subducted sediment if the paleo subduction zone represented by the mafic and ultramafic complex of the catalina schist had continued its thermal and fluid evolution a selvage of similarly enriched rocks might have been generated along the slab mantle wedge contact between 30 and 85 km depth rocks affected by subduction zone metasomatism although rarely recognized at the surface could be volumetrically significant products of the initiation of subduction and may prove to be geochemical probes of convergent margins that approach the significance of xenoliths in the study of other magmatic environments

solution properties of rare earth elements in silicate melts inferences from immiscible liquids abstract the partitioning behavior of rare earth elements ree between immiscible silicate liquids was investigated as a function of temperature and total ree oxide concentration ree preferentially partition into the end member liquids that are rich in network modifying cations with two liquid partition coefficients greater than any other cation the two liquid partition coefficients of ree in a given experiment are essentially identical to one another no evidence was seen to suggest that the solution mechanisms of ree in high silica liquids vary with differences in their ionic radii two lattice models of trace element solution behavior fail to remove the compositional dependence of ree two liquid partition coefficients due to the assumption that all network forming and network modifying cations mix ideally with one another as a result it is probably incorrect to derive physical interpretations from the results of the application of two lattice models the results are applied to the origins of the lree enriched phenocryst matrix partition coefficients seen for some ferromagnesian minerals in high silica rhyolites since liquids with extremely high concentrations of t o t linkages do not strongly discriminate between the ree on the basis of their ionic radii the anomalous ree crystal matrix partition coefficient patterns are best explained as the result of contamination of these minerals by lree accessory phases

ree fractionation between scheelite and apatite in hydrothermal conditions the geochemical analysis of hydrothermal apatite and scheelite pairs from various types of w ore deposits skarns disseminated scheelite and quartz veins provides an insight into ree partitioning between the two minerals among the 18 analyzed pairs only five appear to have grown in equilibrium conditions ten other pairs show more or less important departures from equilibrium the remaining apatite and scheelite pairs have quite different ree patterns indicating crystallization from different fluids both minerals concentrate ree the relative behavior of hree and lree is quite similar in the two minerals scheelite is only slightly more enriched in hree relative to lree than apatite with k ap sch la yb 0 86 0 22 beside these regularities some dispersion in the lanthanide content ratios of apatite and scheelite ranging from 0 6 to 5 may be related to fluid composition the behavior of eu can be related to redox conditions which appear to be more oxidizing in vein associations than in skarn environments determination of ree in coexisting scheelite and apatite seems an efficient tool for identification of successive ore bearing fluids

the early holocene palaeoenvironment of ounjougou mali phytoliths in a multiproxy context abstract the site complex ounjougou on the dogon plateau mali comprises sediments up to 100 000 years old with numerous pleistocene and holocene sequences the site ravin de la mouche 11 4 10 2 ka is of special archaeological significance because in its early holocene deposits pottery sherds have been found which are among the oldest in africa for a better understanding of the environmental conditions which might have contributed to the innovation of pottery making a multi proxy approach was applied to the sediments of ravin de la mouche including phytoliths pollen palynofacies micromorphology and charcoal the multi proxy approach also allows reconstructing the complex taphonomy of the site in our phytolith study we applied a combination of the general and the indices approaches we recorded a maximum of morphotypes and used the summarized data for a calculation of the indices d p ic and iph in comparison with modern surface samples and data from other african phytolith studies with the general approach a number of morphotypes could be detected which are useful in describing the late pleistocene and the early holocene vegetation phytoliths were extracted from the pleistocene base and the early holocene layers ha1 ha2 and ha3 the pleistocene sediment samples with an age of ca 30 40 ka bp have no grass short cell phytoliths gscp and their composition is difficult to interpret ha1 is a coarse fluvial deposit with mainly redeposited phytoliths of pleistocene origin the palaeosoil in ha2 contains phytolith assemblages developed in situ from a terrestrial plant cover the vegetation was an open tropical grassland and a gallery forest with palms and marantaceae annuals from the grass subfamilies chloridoideae and panicoideae probably with a low biomass production dominated the grassland this might explain the insignificant role of fire as indicated by the very low number of micro charcoals ha3 results from a rhythmic deposition of alluvial sediments pointing to pronounced seasonality of rainfall and discharge it contains pollen charcoal and phytolith assemblages with a similar composition as in ha2 the early holocene annual grassland on the dogon plateau probably harboured a high number of species from the grass subfamily panicoideae with edible grains we suggest that the massive expansion of useful panicoid grasses during the early holocene triggered the development of important cultural innovations mainly pottery production cooking wild cereal grains in a ceramic container would have enabled a very effective exploitation of the vast sahelo sudanian grasslands which remained to be successful until modern times

redistribution of rare earth elements thorium and uranium over accessory minerals in the course of amphibolite to granulite facies metamorphism the role of apatite and monazite in orthogneisses from southwestern norway the amphibolite to granulite facies transition has been studied in a high k calc alkaline hornblende biotite k feldspar megacrystic augen gneiss series from the rogaland vest agder rog va sector of the sveconorwegian province southwest norway hornblende begins to break down mainly to clinopyroxene at the cpx in isograd and biotite mainly to orthopyroxene at the opx in isograd abbreviations for minerals following kretz 1983 the magmatic accessory mineral association comprises titanite and allanite which begin to break down before the cpx in isograd titanite is preserved as relict inclusions in other minerals at higher grade monazite and thorite formed in the breakdown of allanite monazite abundance reaches a maximum between the cpx in and opx in isograds the middle and heavy rare earth element m hrees except eu content of apatite steeply increases with increasing metamorphic grade and is directly correlated to the decrease of the modal abundances of titanite hornblende and biotite the u contents of apatite are low and do not increase with metamorphic grade the light rare earth elements lrees and th content of apatite are not correlated to the breakdown of allanite around the cpx in isograd but increase around the opx in isograd a simplified equation is proposed for monazite crystallisation in the vicinity of the cpx in isograd that accounts for the allanite titanite and hornblende breakdowns and the m hree substitution in apatite 3 m hree 2o3in hornblende and litanite 3 lree 2in allaniteo3 2ca5 po4 3apatite f oh 6sio2quartz 6 lree pmonaziteo4 2ca2 m hree 3 sio4 3 f oh lessingite in apatite 6caoin plagioclase at the opx in isograd the increase of lrees and th content of apatite results either from the breakdown of some monazite 3 lree po4monazite 3sio2quartz 4caoin plagioclase f2 h2o fluid ca5 po4 3 f oh apatiteca2 lree 3 sio4 3 f oh less ingite in apatite or the breakdown of the remaining allanite 3 lree 2o3in allanite 6sio2quartz 4caoin plagioclase f2 h2o fluid 2ca2 lree 3 sio4 3 f oh lessingite in apatite the release of fluorine from the breakdown of biotite at the opx in isograd may increase apatite stability relatively to monazite in the granulite facies when compared to amphibolite facies the granulite facies augen gneisses do not show any u or th depletion this means that changes in the accessory mineral associations and the simultaneous breakdown of hydrous minerals at the amphibolite granulite facies transition do not inevitably result in depleted granulite facies rocks but rather to an isochemical element redistribution the coexistence of small amounts of metamorphic monazite and of relict inclusions of titanite in upper amphibolite facies augen gneisses suggests that high k calc alkaline orthogneisses are a suitable material to date with the u pb method prograde path of amphibolite facies regional metamorphism on monazite and the cooling path on titanite

calibrating grass phytolith assemblages in climatic terms application to late pleistocene assemblages from kansas and nebraska abstract the use of modern phytolith assemblages for the interpretation of fossil phytolith assemblages demonstrates the utility of phytolith analysis in reconstructing grassland vegetation and climate in the great plains of north america the modern data presented are the typical average assemblages for 34 modern localities taken throughout the great plains modern assemblage variability across the region is substantial this variability shows a coherent geographical pattern consistent with modern grassland composition these modern phytolith assemblages are calibrated in terms of modern climate data specifically july mean temperature seven fossil assemblages from three late pleistocene localities in the central great plains are presented two alternative phytolith temperature regression models are applied to these fossil assemblages to estimate paleo temperature resulting estimates are consistent with other efforts to calculate late pleistocene temperature departures in the region ca 8 0 to 7 0 c the fossil data also show rapid change in grassland composition and climate during the pleistocene holocene transition these results demonstrate how phytolith analysis can complement or substitute for pollen analysis in the great plains of north america

partitioning in ree saturating minerals theory experiment and modelling of whitlockite apatite and evolution of lunar residual magmas we present compositions including rees determined by ion microprobe of apatite and whitlockite in lunar rock assemblages rich in incompatible trace elements total concentrations of ree oxides in whitlockites range from 9 13 wt and those in apatites range from 0 15 to 1 wt ratios of ree concentrations in whitlockite to those in coexisting apatite range from 10 to 60 the distribution of mg and fe between apatite and whitlockite is correlated to that of coexisting mafic silicates magnesium is strongly preferred by whitlockite and fe is preferred by apatite incorporation of rees in whitlockite is dominated by the coupled substitution of 2ree3 in ca b sites vacancy in ca iia for 2ca 2 in ca b sites and ca2 na in ca iia other substitutions account for only a small portion of the rees in whitlockite over the observed concentration range thus ree concentrations become partially saturated as the primary substitution approaches its stoichiometric limit of two rees per fifty six oxygens leading to reduced whitlockite melt distribution coefficients e g decreasing from twenty five to ten for nd the ree concentrations of lunar residual melts are not depleted by whitlockite crystallization in assemblages consisting mainly of other minerals in typical proportions distribution coefficients for the rees in lunar apatite appear to be low and variable e g 0 2 0 8 for nd variations in the modal ratio of whitlockite to apatite specifically the abundance of whitlockite lead to a range of ree concentrations in the phosphates and variations in the magnitude of ree concentration ratios between whitlockite and apatite if apatite crystallizes before whitlockite or in the absence of whitlockite as textures in several samples indicate then apatite zoned in rees and apatite crystals of different ree concentrations may occur in a given sample provided there is some amount of fractional crystallization and apatite does not later equilibrate this may occur because in the absence of whitlockite in the crystallizing assemblage the rees are highly incompatible relative to the crystalline assemblage so ree concentrations in lunar residual melts increase strongly during small increments of late stage crystallization once whitlockite begins to crystallize bulk distribution coefficients for the rees although still 1 are only mildly incompatible so the change in ree concentrations of residual melts with further crystallization is small consistent with the lack of ree zoning in whitlockite the ree concentrations in lunar whitlockites are modelled as resulting mainly from equilibrium crystallization of the assemblages in which they occur metasomatism or other secondary metamorphic processes are not indicated local melt pocket equilibrium at advanced stages of crystallization may lead to variable ree concentrations and variable whitlockite apatite concentration ratios within the same sample parent melts with extremely high ree concentrations are not required in order to crystallize ree rich lunar whitlockite if modal proportions of whitlockite are low

rare earth elements in apatite uptake from h2o bearing phosphate fluoride melts and the role of volatile components the partitioning of rare earth elements rees between fluorapatite fap and h sub 2 o bearing phosphate fluoride melts has been studied at about 700 and 800 degrees c and 0 10 0 15 gpa ree uptake patterns i e plots of d ree fap melt are convex upwards and peak near nd for single ree substituted fap at minor 0 03 0 25 wt ree sub 2 o sub 3 abundances and binary lree hree substituted fap and hexa ree substituted fap at minor to major 0 25 7 8 wt ree sub 2 o sub 3 abundances partition coefficients for minor abundances of ree and depolymerized phosphate melts are about 5 8 and 1 for la nd and lu respectively and broadly comparable to those for early fluorapatite in the fractionation of melts of basaltic composition the ca2 site exerts marked control on the selectivity of apatite for ree because it preferentially incorporates lree and its effective size varies with substitution of the a site volatile anion component f cl oh using simple crystal chemical arguments melt or fluid normalized ree patterns are predicted to peak near nd for fluorapatite and be more lree enriched for chlorapatite these predictions are consistent with data from natural rocks and laboratory experiments the wide variation in d ree apatite melt in nature from 1 for whitlockite bearing lunar rocks to about 100 for evolved alkalic rocks ismore attributed largely to the influence of the volatile components 49 refs 8 figs 3 tabs less

coupled substitutions involving rees and na and si in apatites in alkaline rocks from the ilimaussaq intrusion south greenland and the petrological implications ansrnlcr apatites from the ilimaussaq augite syenite the sodalite foyaite and a qtartz bearing peralkaline pegmatite have been analyzed using an electron microprobe for the major elements plus na si and selected rare earth elements rees in all three rock types the maximum reeto3 content in the apatite exceeds 16 0 wt0 0 apatite from the augite syenite and primary apatite from the sodalite foyaite are characterizedby a low na content that varies independently of the ree content the composition of these apatites approaches 25 molo o of the end member carreq sio4 3 oh f cl lessingite in response to the substitution ree3 sia ca2 ps ree and na enriched apatites from the quartzbearing peralkaline pegmatite are almost si free and rees and na are positively correlated the composition of these apatites approaches 25 molo o of the hypothetical endmember na5ree5 po4 6 oh f ci 2 in response to the substitution na ree3 2ca2 the compositional trend of late crystalllzing apatite from the sodalite foyaite reflects almost equal contributions of the two substitutions the relationship between these substitutions in a given apatite and its associated mineral assemblage indicates that the na component is only present in considerable amounts when apatite crystallizes in a strongly peralkaline environment

apatite liquid partition coefficients for the rare earth elements and strontium abstract sixteen sets of apatite liquid partition coefficients dap liq for the rare earth elements ree la sm dy lu and six values for sr were experimentally determined in natural systems ranging from basanite to granite the apatite melt glass assemblages were obtained from starting glasses artificially enriched in ree sr and fluorapatite components these were run under dry and hydrous conditions of 7 5 20 kbar and 950 1120 c in a solid media piston cylinder apparatus an sem equipped electron microprobe was used for subsequent measurement of ree and sr concentrations in coexisting apatites and quenched glasses the resulting partition coefficient patterns resemble previously determined apatite phenocryst groundmass concentration ratios in the following respects 1 the rare earth patterns are uniformly concave downward i e the middle ree are more compatible in apatite than the light and heavy ree 2 dreeap liq is much higher for silicic melts than for basic ones and 3 strontium and therefore eu2 is less concentrated by apatite than are the trivalent ree the effects of both temperature and melt composition on dreeap liq are systematic and pronounced at 950 c for example a change in melt sio2 content from 50 to 68 wt causes the average ree partition coefficient to increase from 7 to 30 a 130 c increase in temperature on the other hand results in a two fold decrease in dreeap liq partitioning of sr is insenstitive to changes in melt composition and temperature and neither the sr nor the ree partition coefficients appear to be affected by variations in pressure or h2o content of the melt the experimentally determined partition coefficients can be used not only in trace element modelling but also to distinguish apatite phenocrysts from xenocrysts in rocks reported apatite megacryst host basalt ree concentration ratios 12 for example are considerably higher than the equilibrium partition coefficients which suggest that in this particular case the apatite is actually xenocrystic a reversal experiment incorporated in our study yielded diffusion profiles of ree in apatite from which we extracted a ree ca interdiffusion coefficient of 2 4 10 14 cm2 s at 1120 c extrapolated downward to crustal temperatures this low value suggests that complete ree equilibrium between felsic partial melts and residual apatite is rarely established

observation of mesoscale ocean features in the northeast pacific using geosat radar altimetry data in this paper geosat altimetry data from the northeast pacific are examined the data are 1 binned data on 1 latitude by 2 longitude blocks and 2 collinear track data the binned data cover the region from 20 n to 60 n from the north american coast westward to 150 w and span from december 15 1986 to june 1 1989 to examine the data for evidence of westward propagation of sea level anomalies three zonal transects 45 n 49 n and 57 n are made complex empirical orthogonal function analysis of the data transects at these latitudes reveals phase speed and amplitude information the first eigenmode at each latitude has a very strong annual signal two dimensional spectral analysis of the first eigenmode at 45 n and 57 n shows westward propagation of sea level anomalies at 45 n only the propagating features are annual in period and of order 1000 km in length at 57 n westward propagation is evident as at 45 n but there is also an eastward component to examine the variability of the coastal sea level signal collinear track data from three ascending tracks crossing the gulf of alaska are analyzed revealing mesoscale features of the order of 100 km that parallel the canadian and alaskan coast the most notable feature is the sitka eddy westward propagation of several of these features is observed the results from the analysis of both types of geosat data are compared with other observational data

taphonomy of phytoliths and macroplants in different soils from olduvai gorge tanzania and the application to plio pleistocene palaeoanthropological samples the abundance and types of phytoliths in the fossil record are taphonomically biased and do not correspond with the macroplant record to better understand the bias and improve the interpretation of samples from olduvai gorge tanzania we analysed the phytoliths from three sample sets modern grasses sedges palm and dicots in the area modern soils in the area and the fossil soils from the eastern palaeolake margin in lowermost bed ii fourier transform infrared spectrometry analyses were performed in parallel to compare the mineral composition of both modern soils and fossil soils we found that the abundance of phytoliths is greatly reduced in soil samples compared with modern plant material but the morphotypes can be reliably interpreted dicotyledonous wood bark phytoliths appear to be over represented in the soil types grass phytoliths and sedges to a lesser degree are preserved in the soils but in lower abundances resulting in these groups being under represented the macroplant fossils are fragments of grass and sedge aerial culms and dicotyledonous stems that are preserved in fluvial and lacustrine deposits it is suggested that phytoliths represent the continuous flora whereas macroplant fossils represent the more robust tissues of selected plants preserved under more catastrophic conditions a post depositional model is proposed and the palaeovegetation is reinterpreted as being richer and more complex than indicated by other fossil data

rare earth elements in old biogenic apatites abstract the ree distributions in individual upper devonian conodonts have been measured by ion probe the patterns of all analyzed conodonts are enriched in middle ree eu gd and have a weak or no ce anomaly concentrations and la yb or la sm ratios vary very little within or among individuals from the same zone which suggests that uptake of labile ree from sediments was essentially quantitative therefore the ree signature of the primary carriers probably organic and oxyhydroxides particulates from marine suspensions was efficiently transferred to biogenic apatites and survived late diagenetic processes ree patterns of conodonts do not resemble those of present day seawater and post cretaceous biogenic phosphates which are typically depleted in nd and sm with a negative ce anomaly since ree distributions in the modern water column mimic those of nutrients we assume that in pre cretaceous seawater they were not controlled by surface biological activity we assume instead that ree in pre cretaceous seawater can be explained by mechanism of desorption adsorption on particle surfaces progressive extraction of lree from river water by oxyhydroxides leads to precipitates enriched in middle ree a simple quantitative model was calculated in order to illustrate the proposed mechanism

interdecadal variations in the alaska gyre abstract climatic dynamic topography variations in the alaska gyre during the period 1968 1990 are described with an objective analysis of more than 12000 std and xbt stations and coads wind stress data interannual dynamic height and sst variations were correlated and were consistent with recently described large scale climatic shifts in the north pacific the gyre was cantered more to the east circulation appeared stronger and sst was lower during the early to mid 1970s than during the 1980s the aleutian low np and pna indices intensified during the interim but the response did not appear as a gyre spinup instead the associated wind stress anomalies forced a slowly varying dynamic height anomaly across the eastern and northern part of the gyre through ekman convergence which had the effect of displacing the gyre s low somewhat to the wsw in the 1980s the wind curl spectrum was white and the slow oceanic response was modelled as stochastic forced climate variability with a simple first order m

rare earth element distributions among minerals in a granodiorite and their petrogenetic implications a study of the distribution of lanthanide rare earths in a granodiorite from the eastern peninsular ranges batholith southern california reveals that a large fraction of the ree in this rock resides in the accessory phases sphene and allanite the minerals plagioclase alkali feldspar biotite epidote and apatite each contribute approximately 1 or less of each ree to the whole rock with the exception of eu for which plagioclase contributes 7 sphene and allanite together contain 80 to 95 of each ree each of these phases is zoned in ree concentration with substantial decreases from core to margin textural observations argue for relatively early saturation and precipitation of sphene and allanite in the magma ree zoning trends in sphene and allanite and unexpectedly low ree concentrations in largely later crystallizing minerals such as feldspar indicate that the precipitation of sphene and allanite significantly reduced ree concentrations in residual melts these results illustrate the potential that sphene and allanite have for controlling the behavior of ree in granitic magmas available information collectively suggest that the sampled granodiorite existed as a complete melt that the ree contained in the assemblage of phases were derived by direct crystallization from the melt and that the melt behaved essentially as a closed system once crystallization of the phases now present began close correspondences between the major and trace element chemistries of the granodiorite and phenocryst poor lavas from similar tectonic settings support these conclusions the ree pattern of the granodiorite melt appears to have originated at depth and is characteristic of its source regions and derivation mechanism the high liquidus temperature of a granodiorite melt 1000 c indicates the importance of mantle derived components within the sources of batholithic magmas in the peninsular ranges

rare earth element carriers in the shergotty meteorite and implications for its chronology ion probe measurements of the rare earth element ree concentrations of individual grains of the shergotty meteorite are reported phases analyzed include whitlockite apatite baddeleyite augite pigeonite maskelynite and k rich glass u concentrations of whitlockite and apatite crystals were also obtained the whole rock ree pattern is dominated by whitlockite which contains over 95 of the light rare earth elements lree ree concentrations in apatite are much lower than estimated by laulet al 1986 all the whitlockites whether intergrown with pyroxene equant or interstitial have the same relative abundances of lree i e patterns are almost flat from la to sm the observation by joneset al 1985 of a skeletal whitlockite with lree enrichment is not confirmed by analyses of the same grain pyroxene rims are not enriched in lree no leachable carrier enriched in lree and associated with pyroxene laulet al 1986 jagoutz and wanke 1986 has been found instead either a laboratory contamination or a petrographically cryptic phase such as a film on grain boundaries is suspected as the carrier of lree enrichments if a grain boundary film carries the enrichments it would not be resistant to the metamorphic resetting which has affected other isotopic reservoirs in this sample thus there is no compelling reason to consider the sm nd pyroxene leachates line jagoutz and wanke 1986 as a 360 m y isochron estimates of ree abundances in the shergotty intercumulus melt indicate that a complex petrogenesis is required in agreement with the conclusions of mckayet al 1986a pyroxene distribution coefficients measured experimentally mckayet al 1986a are compared with estimates from measured ree abundances in augite and pigeonite evolution of ree abundances in the shergotty late stage interstitial melt as inferred from analyses of whitlockite conforms with trends predicted from partitioning considerations and requires no special processes such as metasomatism the average u concentrations of whitlockite and apatite are respectively 540 and 1 550 ppb although the calcium phosphates are enriched in u they contain less than 20 of the u in shergotty

the influence of an alaskan stream eddy on flow through amchitka pass flow into the bering sea through amchitka pass in the central aleutian islands is shown to respond to the presence of a large meander eddy in the alaskan stream south of the pass maximum flow into the aleutian basin of the bering sea occurs when the eddy center lies nearest to the axis of amchitka pass a conceptual model of low frequency circulation variability within the bering sea based upon results of empirical orthogonal function analyses of sea surface height anomalies measured by the geosat radar altimeter is presented

low frequency isopycnal variability in the alaska gyre from argo abstract the deployment of a large number of argo floats in the northeast pacific ocean since 2001 has led to a great increase in the volume of data available to study the regional variability on interannual to decadal time scales in this paper gridded fields of hydrographic data from argo are used to examine the low frequency variability of representative isopycnal surfaces over the alaska gyre in the eastern subpolar north pacific anomalies in the depth of isopycnal surfaces and spice anomalies on these surfaces are considered over the 14 year period 2004 2017 an eof analysis is used to characterize the variability occurring at large scales over the region the leading mode of isopycnal depth anomalies through the upper 1000 m of the water column is found to be related to the pacific decadal oscillation the response of a stochastic climate model driven by local ekman pumping is shown to give a reasonable account of variability in the depth of the shallow main pycnocline over the alaska gyre although ocean dynamics must play a role in shaping the spatial response to the wind forcing evidence is presented for counter propagating isopycnal depth anomalies in the subarctic current at the depth of the main pycnocline propagation is dominated by disturbances that are advected eastward by the mean flow at greater depths isopycnal depth anomalies propagate westward at approximately twice the speed of first mode long baroclinic rossby waves consistent with the propagation of rossby waves seen in altimetric observations of sea surface height variability the eastward advection of spice anomalies is also evident in the upper ocean however the dominant signal in the record is a large scale positive spice anomaly that forms locally on subsurface isopycnals evidence is presented that this anomaly arises mainly from the downward diffusion across the pycnocline of heat associated with the marine heatwave of 2013 14 over the northeast pacific the extent to which anomalies are generated locally may limit the potential for decadal prediction of upper ocean conditions over the region