comment on the paper w and m type tetrad effects in ree patterns for water rock systems in the tono uranium deposit central japan takahashi et al 2002 have determined the rare earth element ree concentrations of weathered granite and related groundwater samples from the tono area central japan the chondrite normalized ree distribution patterns of rock and water samples were found to exhibit the lanthanide tetrad effect the ree distribution patterns of the weathered granite were typified by a convex m shaped tetrad effect whereas the groundwater samples showed lanthanide distribution patterns with a concave w shaped tetrad effect based on this observation it was suggested that the m shaped tetrad effect of the granite primarily represents a residual ree pattern resulting from the extraction of a mirroring w shaped tetrad effect by the groundwater this interpretation was further substantiated by the observation that sedimentary rocks in the tono area show ree distribution patterns with a w shaped tetrad effect implying that fixation of groundwater ree onto the sedimentary rocks was significant takahashi et al 2002 suggested that the size of the tetrad effect in the ree distribution patterns of

origin of convex tetrads in rare earth element patterns of hydrothermally altered siliceous igneous rocks from the zinnwald sn w deposit germany the chondrite normalized rare earth element ree patterns of whole rock samples from evolved granitic systems hosting rare metal deposits sometimes show a split into four consecutive curved segments referred to as tetrads in the present contribution a rigorous statistical method is proposed that can be used to test whether geological significance should be attributed to tetrads that are only of limited size the method involves a detailed evaluation of element and sample specific random and systematic errors that are constrained on the basis of independent repeated preparations and analyses of sample and reference materials application of the proposed method to samples from the granite hosted zinnwald sn w deposit germany revealed that at least two tetrads in normalized whole rock ree patterns have to be analytically significant to rule out that fractional crystallization led to the unusual behavior of the rees based on the analysis of altered albite granite and greisen samples from the endocontact of the zinnwald granite massif it is demonstrated that the lanthanide tetrad effect is responsible for the formation of the convex tetrads geological and petrological evidence suggests that the tetrads in the samples developed prior to greisenization and related cassiterite precipitation in contrast to the endocontact samples the rhyolitic wall rocks are typified by normalized ree patterns having tetrads that are variable in size and frequently close to the limit of analytical significance the sizes of the tetrads apparently correlate with the intensity of albitization but show no relation to subsequent alteration processes including greisenization and low temperature argillization this observation proves that curved segments in normalized whole rock ree patterns can be introduced during hydrothermal fluid rock interaction

highly evolved juvenile granites with tetrad ree patterns the woduhe and baerzhe granites from the great xing an mountains in ne china abstract in ne china voluminous granitoids were emplaced in late paleozoic and mesozoic times we report here sr nd o isotopic and elemental abundance data for two highly evolved granitic plutons woduhe and baerzhe from the great xing an mountains they show a rather juvenile sr nd isotopic signature and a spectacular tetrad effect in their ree distribution patterns as well as non charac charge and radius controlled trace element behavior the emplacement ages are constrained at 130 4 ma for the woduhe and 122 5 ma for the baerzhe granites by rb sr and sm nd isotope analyses both granites are also characterized by low but imprecise initial 87sr 86sr ratios of about 0 703 the nd sr isotope data argue for their generation by melting of dominantly juvenile mantle component with subordinate recycled ancient crust this is largely compatible with the general scenario for much of the phanerozoic granitoids emplaced in the central asian orogenic belt the parental magmas for both the woduhe and baerzhe granites have undergone extensive magmatic differentiation during which intense interaction of the residual melts with aqueous hydrothermal fluids probably rich in f and cl resulted in the non charac trace element behavior and the tetrad effect of ree distribution both the woduhe and baerzhe granites show the characteristic trace element patterns of rare metal granites but their absolute abundances differ by as much as two orders of magnitude the oxygen isotope compositions of the two granites have been severely disturbed significant 18o depletion in feldspar but not so much in quartz suggests that the hydrothermal alteration took place in a temperature condition of 300 500 c this subsolidus hydrothermal alteration is decoupled from the late stage magma fluid interaction at higher temperatures despite the two distinct and intense events of water rock interaction the rb sr and sm nd geochronological systems seem to have maintained closed hence suggesting that the two events occurred shortly after the plutonic emplacements

the weddell sea region an important precipitation channel to the interior of the antarctic ice sheet as revealed by glaciochemical investigation of surface snow along the longest trans antarctic route

impurity sources of f cl no3 and so4 2 in greenland and antarctic precipitation five polar impurity sources are proposed anthropogenic no3 and so42 in recent greenland but not antarctic snow marine aerosols the dominant cl source volcanic eruptions which produce detectable but variable peaks in so42 f and or cl concentrations biogenic sulfurous gases from soil and coastal waters the dominant source for so42 in nonvolcanic strata an unidentified source of background nitrate which is more active in the northern hemisphere and which displays a summer concentration maximum solar activity and supernova events do not modulate no3 concentrations in greenland snow

quartz and feldspar zoning in the eastern erzgebirge volcano plutonic complex germany czech republic evidence of multiple magma mixing abstract zoned quartz and feldspar phenocrysts of the upper carboniferous eastern erzgebirge volcano plutonic complex were studied by cathodoluminescence and minor and trace element profiling the results verify the suitability of quartz and feldspar phenocrysts as recorders of differentiation trends magma mixing and recharge events and suggest that much heterogeneity in plutonic systems may be overlooked on a whole rock scale multiple resorption surfaces and zones element concentration steps in zoned quartz ti and feldspar phenocrysts anorthite content ba sr and plagioclase mantled k feldspars etc indicate mixing of silicic magma with a more mafic magma for several magmatic phases of the eastern erzgebirge volcano plutonic complex generally feldspar appears to be sensitive to the physicochemical changes of the melt whereas quartz phenocrysts are more stable and can survive a longer period of evolution and final effusion of silicic magmas the regional distribution of mixing compatible textures suggests that magma mingling and mixing was a major process in the evolution of these late variscan granites and associated volcanic rocks quartz phenocrysts from 14 magmatic phases of the eastern erzgebirge volcano plutonic complex provide information on the relative timing of different mixing processes storage and recharge allowing a model for the distribution of magma reservoirs in space and time at least two levels of magma storage are envisioned deep reservoirs between 24 and 17 km the crystallisation level of quartz phenocrysts and subvolcanic reservoirs between 13 and 6 km deflation of the shallow reservoirs during the extrusion of the teplice rhyolites triggered the formation of the altenberg teplice caldera above the eastern erzgebirge volcano plutonic complex the deep magma reservoir of the teplice rhyolite also has a genetic relationship to the younger mineralised a type granites as indicated by quartz phenocryst populations the pre caldera biotite granites and the rhyodacitic schonfeld volcanic rocks represent temporally and spatially separate magma sources however the deep magma reservoir of both is assumed to have been at a depth of 24 17 km the drastic chemical contrast between the pre caldera schonfeld westfalian b c and the syn caldera teplice westfalian c d volcanic rocks is related to the change from late orogenic geotectonic environment to post orogenic faulting and is considered an important chronostratigraphic marker

oxygen isotope and total beta radioactivity measurements on 10 m ice cores from the antarctic peninsula as part of the glaciology of the antarctic peninsula gap programme the snow cover at 25 stations was sampled to 10 m depth for oxygen isotope and total radioactivity analysis the mean annual oxygen isotope ratio correlates satisfactorily with 10 m temperature despite the complex topography of the area and suggests on average that climatic trends in the region are fairly systematic the relationship with temperature is similar to that derived from a simple model in which an air mass initially of maritime subtropical characteristics is progressively cooled as it moves towards the region the detailed isotope profiles show that for future deep drilling the most easily interpretable climatic information will be found in the more continental areas on the cast coast and on the plateau in the south of the region the degree of continentality of particular sites is reflected in the amplitude of the annual wave in the upper portion of the isotope ratio profile as well as in the accumulation rate

temporal variations in marine chemical concentrations in coastal areas of eastern antarctica and associated climatic causes abstract snow pit and a firn core samples obtained from coastal areas in the eastern lambert basin of eastern antarctica enabled us to investigate the temporal variations in soluble marine ion concentrations and the possible mechanisms influencing their variations the concentrations of seasonal sea salt ions na cl and mg2 at the coastal site lh406 were maximal in the spring and minimal in the summer broad maximal values also occurred in the winter and minimal values occurred in the summer in the interior site zg050 the sea ice extent sie in the indian ocean sector of eastern antarctica followed similar temporal distribution patterns two sulfur compounds so42 and msa experienced seasonal variations similar to those observed for sea salt ions at the lh406 site however distinct variations were reported at the zg050 site the variations in nssso42 levels in the zg050 snow pit that occurred over a 14 year period were positively correlated with variations in sie however this relationship was different from that at the western lambert basin the change in direction of the supplementary prevailing wind during 1994 1995 produced a significant change in the concentrations of marine ions a change in the source region may be the primary cause of this difference

the distribution of nitrate content in the surface snow of the antarctic ice sheet along the route of the 1990 international trans antarctica expedition previous work showed that nitrate measured at very high resolution 1 5 cm in snow depositional sequences in antarctica could be correlated with short term phenomena such as solar proton events dreschhoff and zeller 1990 it was clear that deposition of the ionization products in the snow is strongly dependent upon precipitation and atmospheric conditions during and immediately after the event information about the geographic distribution of the nitrate fallout over antarctica was limited to only a few sites however a unique opportunity to examine this aspect of the nitrate distribution and to test more fully the hypothesis that atmospheric ionization from solar charged particles is responsible for a significant portion of nitrate was presented to us by a set of surface snow samples collected by the international trans antarctica expedition foot traverse the set of 95 samples of the upper 25 cm was collected by one of us qin at roughly equal distances along the 5736 km route from july 27 1989 to march 3 1990 samples are distributed along a track from 65 05 s 59 35 w through 90 s to 66 33 s 95 39 e which represents geomagnetic latitudes 50 s west longitude to 77 s east longitude the profiles of nitrate concentration and flux along the route were plotted and indicate that especially at the higher elevation of the polar plateau the distribution may be affected by electron precipitation

formation of extremely f rich hydrous melt fractions and hydrothermal fluids during differentiation of highly evolved tin granite magmas a melt fluid inclusion study quartz crystals from topaz zinnwaldite albite granites from zinnwald erzgebirge germany contain in addition to primary and secondary fluid inclusions fis abundant crystalline silicate melt inclusions mis with diameters up to 200 m these mis represent various stages of evolution of a highly evolved melt system that finally gave rise to granite related sn w mineralization the combination of special experimental techniques with confocal laser raman microprobe spectroscopy and empa permits precise measurement of elevated contents of h2o f and b in re homogenized mis the contents of h2o and f were observed to increase from 3 to 30 and 1 9 to 6 4 wt respectively during magma differentiation however there is a second mi group very rich in h2o with values up to 55 wt h2o and an f concentration of approximately 3 wt ongoing enrichment of volatiles h2o f b and cl and of cs and rb can be explained in terms of magma differentiation triggered by fractional crystallization and thus is suggested to reflect elemental abundances in natural magmas and not boundary layer melts partitioning between melt and cogenetic fluids has further modified the magmatic concentrations of some elements particularly sn the coexistence of two types of mis with primary fis indicates fluid saturation early in the history of magma crystallization connected with a continuous sequestration of sn f and b the results of this study provide additional evidence for the extraordinary importance of the interplay of h2o f and b in the enrichment of sn during magma differentiation by decreasing the viscosity of and increasing the diffusivity in the melts as well as by the formation of various stable fluoride complexes in the melt and coexisting fluid

laboratory antarctica research contributions to global problems research in antarctica is becoming increasingly important in the large interdisciplinary studies of connections within the earth9s geosphere biosphere system four examples of broad research areas are discussed upper atmosphere research explores the sun earth interactions which are most intense in the polar regions the mass balance and dynamics of the large antarctic ice sheet and its paleoclimatic records recovered from deep ice cores are important indicators of past and present global changes antarctica and sediment cores from the southern ocean contain the history of inception and growth of the ice masses and their subsequent fluctuations and the long term history of paleoclimate the remarkable adaptations of antarctic biota to extreme cold and drought may allow through biotic monitoring the detection of changes in the ocean and climate of antarctica

snow chemistry across antarctica un updated compilation of published and new data of major ion ca cl k mg na no3 so4 and methylsulfonate ms concentrations in snow from 520 antarctic sites is provided by the national itase international trans antarctic scientific expedition programmes of australia brazil china germany italy japan korea new zealand norway united kingdom the united states and the national antarctic programme of finland the comparison shows that snow chemistry concentrations vary by up to four orders of magnitude across antarctica and exhibit distinct geographical patterns the antarctic wide comparison of glaciochemical records provides a unique opportunity to improve our understanding of the fundamental factors that ultimately control the chemistry of snow or ice samples this paper aims to initiate data compilation and administration in order to provide a framework for facilitation of antarctic wide snow chemistry discussions across all itase nations and other contributing groups the data are made available through the itase web page http www2 umaine edu itase content syngroups snowchem html and will be updated with new data as they are provided in addition recommendations for future research efforts are summarized

metal fractionation between magmatic brine and vapor determined by microanalysis of fluid inclusions the major and trace element compositions of individual fluid inclusions from a range of magmatic hydrothermal ore deposits were analyzed by laser ablation inductively coupled plasma mass spectrometry to explore the behavior of ore forming components during fluid phase separation boiling in high temperature saline fluid systems data from 13 samples showing unambiguous evidence for coeval trapping of a liquid brine and a coexisting vapor phase identify two groups of elements with drastically different geochemical behavior na k fe mn zn rb cs ag sn pb and tl preferentially partition into the brine probably as cl complexes whereas cu as au probably as hs complexes and b selectively partition into the vapor fluid phase separation is probably a major previously underestimated process in the chemical differentiation that contributes to the extreme range of selective element enrichments in magmatic hydrothermal systems from deep plutons through porphyry style and greisen deposits to epithermal mineralization and volcanic fumaroles

the lanthanide tetrad effect and its correlation with k rb eu eu sr eu y ho and zr hf of evolving peraluminous granite suites lanthanide tetrad effects are often observed in ree patterns of more highly evolved variscan peraluminous granites of mid eastern germany central erzgebirge western erzgebirge fichtelgebirge and northern oberpfalz the degree of the tetrad effect te1 3 is estimated and plotted vs k rb sr eu eu eu y ho and zr hf the diagrams reveal that the tetrad effect develops parallel to granite evolution and significant tetrad effects are strictly confined to highly differentiated samples mineral fractionation as a cause for the tetrad effect is not supported by a calculated rayleigh fractionation which also could not explain the fractionation trends of sr eu and eu eu the strong decrease of eu concentrations in highly evolved rocks suggests that eu fractionates between the residual melt and a coexisting aqueous high temperature fluid mineral fractionation as a reason for the tetrad effect is even more unlikely as ree patterns of accessory minerals display similar tetrad effects as the respective host rocks the accessory minerals inherit the ree signature of the melt and do not contribute to the bulk rock tetrad effect via mineral fractionation these results point in summary to significant changes of element fractionation behavior in highly evolved granitic melts ionic radius and charge which commonly control the element distribution between mineral and melt are no longer the exclusive control the tetrad effect and the highly fractionated trace element ratios of y ho and zr hf indicate a trace element behavior that is similar to that in aqueous systems in which chemical complexation is of significant influence this distinct trace element behavior and the common features of magmatic hydrothermal alteration suggest the increasing importance of an aqueous like fluid system during the final stages of granite crystallization the positive correlation of te1 3 with bulk rock fluorine contents hints at the importance of ree fluorine complexation in generating the tetrad effect as the evolution of a ree pattern with tetrad effect m type implies the removal of a respective mirroring ree pattern w type the tetrad effect identifies open system conditions during granite crystallization

chemical and isotopic evolution of the coastal batholith of southern peru southeast of arequipa the coastal batholith of southern peru is composed of two segments arequipa and toquepala including five superunits which were emplaced in discrete magmatic pulses from the jurassic to the paleocene eras 190 61 ma most superunits intruded a precambrian basement dominated by granulitic and amphibolitic rocks showing a strong enrichment in large ion lithophile elements low end p 21 to 29 and 206pb 204pbp 16 11 17 03 tilton and barreiro 1980 and high esr p 396 to 999 values major and trace element analyses reveal that each superunit is formed by distinct suites of calc alkaline plutons i e i type that range in composition from quartz gabbro to monzogranite for the whole plutonic suite located in southern peru the evolution toward negative end i and positive esr i values is followed by a significant decrease in 206pb 204pbi ratios but is also related to the density of precambrian outcrops this led us to classify the intrusives into three groups group 1 consists of intrusives carrying positive end i 2 4 to 0 4 and generally negative esr i values 7 4 to 0 7 they are located in the ilo moquegua transect 17 22 17 80 s an area where precambrian exposure is scarce group 2 consists of plutons with intermediate e values i e end i 0 5 to 2 2 and esr i 7 1 to 55 7 which are found in the vicinity of arequipa and tarata where numerous precambrian outcrops are present finally group 3 is composed of intrusives showing negative end i 4 4 to 8 0 and positive esr i values 27 1 to 56 1 including one anomalous granodiorite exposed near tarata and two samples collected in the arequipa quadrangle near the contact with the charcani gneiss there are several petrogenetic models which can explain the trace element isotopic and geographic correlations observed within the coastal batholith of southern peru one simple model advocates that the parental mafic magma s of the plutonic suites of each superunit must be ultimately derived from an isotopically depleted mantle wedge above the subduction zone the gabbro diorite granodiorite monzogranite association is formed via fractional crystallization and crustal assimilation i e afc during ascent in the andean crust if the exposed precambrian crust represents a good compositional average of the upper crustal material assimilated then the isotopic and some of the trace element variations observed in the three groups can be related to various amounts of crustal assimilation i e small for group 1 but substantial for group 3 although surprisingly little assimilation is required when considering all southern peruvian intrusives more complex models advocate different parental mafic magmas formed by various mixtures of lower crustal and mantle derived melts both having heterogenous but depleted nd and sr isotopic compositions the parental magmas would then ascend differentiate and assimilate upper crustal materials of different compositions i e a crust similar to the exposed precambrian basement for groups 2 and 3 and a less enriched crust not exposed in the area for group 1 if the first model is correct then the relatively small degree of crustal assimilation experienced during the formation of the coastal batholith of southern peru is consistent with the hypothesis that the thick andean crust was thinned during the prevailing extensional tectonic regime that led to the formation of a marginal basin in central peru during the late mesozoic this allowed the basic magmas to encounter the base of the precambrian section at shallower depth and spend less time ascending and differentiating in this enriched crust effectively limiting the amount of assimilation

different post depositional processes of no3 in snow layers in east antarctica and on the northern qinghai tibetan plateau through comparison of snow pit no 3 profiles from central east antarctica and the northern qinghai tibetan plateau qtp we conclude that no 3 peaks in the uppermost surface snow layers in central east antarctica are not related to an atmospheric signal and that they need to be accounted for by post depositional effects such effects however are not found in the snow pit no 3 profiles from the northern qtp no 3 can be deposited as a gas hno 3 or as a neutral salt particularly by reaction with ammonia to form nh 4 no 3 or fixed by sea salt or terrestrial dust mulvaney and others 1998 thus a difference in speciation between no 3 in snow layers in east antarctica and at the northern qtp is suggested as the reason for the different post depositional processes of no 3 in the two areas

w and m type tetrad effects in ree patterns for water rock systems in the tono uranium deposit central japan abstract abundances of rare earth elements plus y ree were determined for granitic rocks tertiary sedimentary rocks and related groundwater in the tono area central japan tetrad effects concave curves in ree patterns were found for these rocks and groundwater samples conjugate m and w types of tetrad effects were simultaneously observed in these specimens which constitute the water rock system the granitic rocks show the m type tetrad effects while the groundwater and the sedimentary rocks exhibit the w type tetrad effects non chondritic y ho ratios were found especially in the groundwater y ho ratios showed larger values than the chondritic value for the samples showing w type tetrad effects and vice versa these results suggest that 1 preference of the groundwater for a w type tetrad effect and larger y ho ratio than chondrite produces an m type tetrad effects and lower y ho ratios in the granitic rocks during weathering processes 2 the w type tetrad effect and larger y ho ratio for the sedimentary rocks is brought about by the fixation of groundwater ree onto the sedimentary rocks the variation of the tetrad effect and y ho ratio was confirmed by laboratory experiments on the leaching of ree from the granitic rocks the w type tetrad effect and large y ho ratio in the u mineralization zone in the sedimentary rocks were also found by sims analysis which is consistent with the w type tetrad effect and larger y ho ratio in the whole rock abundances of the sedimentary rocks disequilibrium of the u series 234 u 238 u analyzed by sims in the u mineralization zone suggests that the u bearing minerals were formed through precipitation from groundwater as it became reducing these results suggest that the ree in the sedimentary rocks were transported by the groundwater from the granitic rocks in the tono area based on this study it is implied that the degree of the tetrad effects and the variation of y ho ratio can be valuable tools to investigate the migration of ree during water rock interactions in natural systems

origin of topaz bearing and related peraluminous granites of the late devonian davis lake pluton nova scotia canada crystal versus fluid fractionation abstract the davis lake pluton in the late devonian south mountain batholith in southwestern nova scotia canada is composed of peraluminous leucomonzogranites and subordinate topaz bearing leucogranites that host greisens and a primary tin deposit the concentrations of incompatible trace elements e g rb li u f ta and sn and element e g k rb nb ta and la sm and isotopic ratios e g 206 pb 204 pb and 87 sr 86 sr display a spatial zonation the granitic rocks were generated by extensive fractional crystallization of major phases feldspars and biotite and accessory minerals monazite apatite and zircon in a compositionally zoned magma chamber fractional crystallization of the evolving f rich peraluminous granitic magma was accompanied particularly in later stages by fluid fractionation involving fluorine complexing fluid fractionation was a major differentiation process during the terminal stages of the pluton s evolution it played an important role in the genesis of the evolved rocks which are characterized by low k rb 24 150 nb ta 1 6 la sm 1 5 4 and eu eu 0 01 0 3 ratios these ratios as well as the enhanced concentrations of li rb u ta and sn in these rocks correlate with f fluorine rich fluids modified the rb sr and u pb ratios which produced the distinct variations of 87 sr 86 sr and 206 pb 204 pb isotopic ratios the parent magma was formed by dehydration melting of lower crustal metasedimentary rocks the melting was related to crustal thickening in association with terrane and collision along the eastern margin of the appalachians

rare earth element geochemistry and the tetrad effect abstract the tetrad effect is found in the rare earth elements la lu and results from increased stability at quarter half three quarter and complete filling of the 4f electron shell suggestions that this effect is observed in ree patterns of seawater and other geological samples marine phases the mineral kimuraite late stage granitic rocks the mineral uraninite and siliciclastic sediments are not compelling in the cases of seawater and the carbonate mineral kimuraite a discontinuity at gd may be attributed to the tetrad effect but the complexity of the overall controls on these ree distributions leaves such an interpretation uncertain at best unusual ree patterns in leucogranites and pegmatites are best explained by fractionation of trace minerals notably apatite apparent tetrad anomalies in uraninite rees disappear when normalised to upper crustal i e shale abundances analytical difficulties probably explain apparent tetrad effects in some seawater limestone and siliciclastic ree patterns