release of ni from birnessite during transformation of birnessite to todorokite implications for ni cycling in marine sediments abstract the phyllomanganate birnessite is the main mn bearing phase in oxic marine sediments where it exerts a primary control on the concentration of micronutrient trace metals in seawater however during sediment diagenesis and under mild hydrothermal conditions birnessite transforms into the tectomanganate todorokite we have recently shown that the transformation of birnessite to todorokite proceeds via a four stage nucleation and growth mechanism beginning with todorokite nucleation then crystal growth from solution to form todorokite primary particles followed by their self assembly and oriented growth via oriented attachment to form crystalline todorokite laths culminating in traditional crystal ripening atkins et al 2014 here we determine the fate and mobility of ni sorbed by birnessite during this transformation process specifically in our recent work we predict that the presence of ni within the phyllomanganate matrix will disrupt the formation of todorokite primary particles as such contrary to current understanding we suggest that ni sorbed by birnessite will slow the transformation of birnessite to todorokite and or be released to marine porewaters during sediment diagenesis here we transform a synthetic poorly crystalline ni sorbed 1 wt ni hexagonal birnessite analogous to marine birnessite into todorokite under a mild reflux procedure developed to mimic marine diagenesis and mild hydrothermal conditions we characterise our birnessite and reflux products as a time series including x ray diffraction xrd high resolution transmission electron microscopy hr tem and extended x ray absorption fine structure exafs spectroscopy in addition we determine ni speciation and mineral phase associations in a suite of natural marine ferromanganese precipitates containing intermixed phyllomanganate and todorokite our work shows for the first time that ni significantly slows the transformation of birnessite to todorokite and reduces the crystallinity of the neo formed todorokite phase but does not alter the mechanism and pathway of todorokite formation compared to a ni free system furthermore in systems tending towards todorokite as the final diagenetic product we see that up to 50 of the ni originally sequestered by birnessite is released to solution during the transformation our work indicates that the transformation of birnessite to todorokite in oxic marine sediments likely provides a significant source of ni to marine sedimentary porewaters and potentially a hitherto unrecognized benthic flux of ni to seawater

the variety of lithologies in the yamato 86032 lunar meteorite implications for formation processes of the lunar crust abstract we performed a petrologic mineralogical geochemical and isotopic study of several lithologies in the y 86032 feldspathic breccia this study leads us to conclude that y 86032 likely originated on the lunar farside y 86032 is composed of several types of feldspathic clasts granulitic breccias and minor basaltic clasts set in a clastic matrix we identify an an97 anorthosite that has an contents similar to those of nearside fans mg molar mg mg fe 100 values vary significantly from 45 to 80 covering the ranges of both nearside fans and the mg gap between fans and the mg suite a light gray feldspathic lg breccia making up 20 of the investigated slab 5 2 3 6 cm2 mainly consists of fragments of anorthosites an93 anorthosite more sodic than nearside fans lg also contains an augite plagioclase clast which either could be genetically related to the an93 anorthosite or to slowly cooled basaltic magma intruded into the precursor rock the na rich nature of both an93 anorthosite and this clast indicates that the lg breccia was derived from a relatively na rich but incompatible element poor source the mg variation indicates that the an97 anorthosite is a genomict breccia of several types of primary anorthosites granulitic breccias in y 86032 have relatively high mg in mafic minerals the highest mg values in mafic minerals for the an97 anorthosite and granulitic breccias are similar to those of mg rich lithologies recently described in dhofar 489 basaltic clasts in the dark gray matrix are aluminous and the zoning trends of pyroxene are similar to those of vlt or lt basalts the crystallization of these basaltic clasts pre date the lithification age of the clastic matrix at 3 8 ga the low k contents of plagioclase in both the anorthositic and basaltic clasts and generally low incompatible element abundances in all the lithologies in y 86032 indicate that kreep was not involved during the formation of the precursor lithologies this observation further suggests that urkreep did not exist in the source regions of these igneous lithologies all these facts support the idea that y 86032 was derived from a region far distant from the pkt and that the lithic clasts and fragments are indigenous to that region an an97 anorthositic clast studied here has distinct sm nd isotopic systematics from those previously found for another an97 anorthositic clast and an93 anorthosite and suggests either that an97 anorthosites come from isotopically diverse sources or that the sm nd isotopic systematics of this clast were reset 4 3 ga ago these lines of geochemical isotopic and petrologic evidence suggest that the lunar crust is geochemically more heterogeneous than previously thought

europium mass balance in polymict samples and implications for plutonic rocks of the lunar crust abstract from correlations of sm concentration and sm eu ratio with th concentration for a large number of polymict samples from various locations in the lunar highlands and the value of 0 91 g g for the mean th concentration of the highlands surface crust obtained by the orbiting gamma ray experiments we estimate the mean concentrations of sm and eu in the lunar surface crust to be between 2 and 3 g g sm and 0 7 and 1 2 g g eu the compositional trends indicate that there is no significant enrichment or depletion of eu on the average compared to sm relative to chondritic abundances i e there is no significant eu anomaly in average upper crust although rich in plagioclase 70 the upper crust does not offer evidence for a gross vertical separation of plagioclase from the final liquid from which it crystallized this and the chondritic ratio of eu al in average highlands material imply that the net effect of the processes that led to formation of the lunar crust was to put most of the al and incompatible elements in the crust the concentration of eu in most polymict samples from the highlands exceeds that which can be supplied by the fraction of kreep necessary to supply the incompatible trace elements plus the fraction of plagioclase necessary to supply the al if the plagioclase has the composition of that in ferroan anorthosite among plutonic rocks only plagioclase in rocks from the magnesian suite can supply the excess eu in the polymict rocks owing to the intermediate value of the mean mg fe ratio of the crust a significant fraction of the mafic rocks of the lunar highlands must have lower mg fe ratios than the norites and troctolites of the magnesian suite of plutonic rocks a large fraction of the plagioclase in the lunar crust is associated not with ferroan anorthosite but with more mafic rocks e g norite anorthositic norite there is little evidence in the eu data that the lunar crust ever consisted of a thick shell of nearly pure plagioclase as envisioned in some formulations of the magma ocean model of its formation

nucleation and growth of todorokite from birnessite implications for trace metal cycling in marine sediments the phyllomanganate birnessite is the main mn bearing phase in oxic marine sediments and through coupled sorption and redox exerts a strong control on the oceanic concentration of micronutrient trace metals however under diagenesis and mild hydrothermal conditions birnessite undergoes transformation to the tectomanganate todorokite the mechanistic details of this transformation are important for the speciation and mobility of metals sequestered by birnessite and are necessary in order to quantify the role of marine sediments in global trace element cycles here we transform a synthetic poorly crystalline hexagonal birnessite analogous to marine birnessite into todorokite under a mild reflux procedure developed to mimic marine diagenesis and mild hydrothermal conditions we characterize our birnessite and reflux products as a time series employing x ray diffraction xrd fourier transform infrared spectroscopy ftir bet surface area analysis scanning electron microscopy sem high resolution transmission electron microscopy hr tem and extended x ray absorption fine structure spectroscopy exafs we provide new insight into the crystallization pathway and mechanism of todorokite formation from birnessite under conditions analogous to those found in marine diagenetic and hydrothermal settings specifically we propose a new four stage process for the transformation of birnessite to todorokite beginning with todorokite nucleation then crystal growth from solution to form todorokite primary particles followed by their self assembly and oriented growth via oriented attachment to form crystalline todorokite laths culminating in traditional crystal ripening we suggest that contrary to current understanding trace metals like ni might retard the transformation of birnessite to todorokite and be released to marine sedimentary pore waters during this diagenetic process thus potentially providing a benthic flux of these micronutrients to seawater

manganese microchimneys buried in the central pacific pelagic sediments evidence of intraplate water circulation abstract manganese oxide deposits of an irregular tube like shape with unique composition and structure were found within pliocene siliceous sediments from an abyssal hill in the central pacific manganese nodule province effective separation of mn from fe and probably a rapid rate of mn deposition are suggested from the chemical composition a very high mn fe ratio up to 400 and low concentrations of transition metals the ree pattern is similar to other marine low temperature hydrothermal and sub oxic diagenetic mn deposits low total ree abundance and strong negative ce anomaly the deposit consists of major todorokite with minor buserites showing a hydrothermal signature blade like crystals of the minerals typically grow within open tubes several mm thick and lack detrital minerals all data indicate a low temperature hydrothermal or cold seep origin or less likely a sub oxic diagenetic origin this unusual manganese deposit from a pelagic environment is thought to have formed on the sea floor from mn bearing waters that passed through sediments or basement rocks we speculate that intraplate water circulation took place during the late pliocene to pleistocene due to the uplift and or block faulting after the deposition of pelagic pliocene sediments

sixth foray for pristine nonmare rocks and an assessment of the diversity of lunar anorthosites eleven nonmare samples are characterized generally both compositionally and petrographically five are almost certainly pristine ferroan anorthosite 10056c alkali anorthosite 14047c ferroan anorthosite 14312c anorthositic troctolite 14321c3 and granite 14321c4 and four are probably pristine norite 14318c noritic anorthosite 67215 quasi pristine ferroan anorthosite 73217c and norite 78527 five are unique anorthosites extending the diversity of lunar anorthosites considerably alkali anorthosites particularly 14047c are extremely rich in incompatible elements the first anorthosite from apollo 11 with manifestations of pristinity 10056c appears to be a normal member of the ferroan group however the first pristine ferroan anorthosites from apollo 14 and 17 to be studied in detail 14312c and 73217c both have unusually sodic plagioclase by ferroan standards with only 75 plagioclase 67215 is the first large 273 g probably pristine ferroan sample with less than 83 plagioclase the nature of the correlations between longitude and such parameters as eu and sm concentrations and sc sm ti sm and ca na ratios among pristine ant samples has been elucidated because five of the new pristine samples are from a western site apollo 14 interestingly ferroan anorthosite 14312c has ca na sc sm and ti sm ratios close to the normal ferroan values but significantly displaced in the direction of the nonferroan western pristine rocks this suggests that the composition longitude relationships are as old as the late stages of the crystallization of the putative magma ocean

crystal chemistry of ni in marine ferromanganese crusts and nodules marine ferromanganese crusts and nodules are highly enriched in transition metals such as ni and co yet the crystal chemistry and mode of incorporation of these metals is poorly known we characterized the crystal chemistry of ni in two hydrogenetic pacific ocean ferromanganese crust samples and a hydrogenetic nodule from the madeira abyssal plain energy dispersive spectrometry shows that ni is associated with the manganese oxide phases in agreement with previous work x ray diffraction patterns show that the dominant mn3 4 oxide is a phyllomanganate similar to hexagonal birnessite or mno2 extended x ray absorption fine structure spectroscopy shows that the coordination environment of ni results from structural incorporation into the phyllomanganate phase by replacement of mn3 4 in contrast ni initially sorbs to freshly prepared synthetic birnessite by surface complexation over vacancy sites in the mno2 layer we propose that the transformation of ni sorption from surface complexation to structural incorporation provides a potentially irreversible sink for ni in seawater

mineralogy and geochemistry of lunar meteorite queen alexandra range 93069 queen alexandra range que 93069 is a glass rich regolith breccia derived from the lunar highlands the high abundance of glassy fragments the presence of agglutinates the small size of all mineral and glass fragments the presence of mostly melt rocks and the low abundance of pristine lunar crustal rocks all indicate that que 93069 is derived from a mature regolith this conclusion is also supported by its high siderophile element content the most common mafic mineral is pyroxene with compositions that indicate derivation from ferroan ant suite rocks rare gabbro differentiation products may be indicated by the presence of silica fayalitic olivine and one pyroxferroite grain lithic fragments are mostly meta melt rocks of ant composition the glass compositions are dominated by troctolitic anorthosite compositions followed by gabbroic anorthosite and noritic anorthosite most glasses are ol normative in composition some rare basic glasses of noritic composition were observed glass fragments and matrix glasses are alkali poor except for some rare alkali rich shards the bulk chemical composition of que 93069 as well as the rare earth element ree abundance pattern is very similar to that of other highlands meteorites such as mac 88105 and y 86032 and to average lunar highlands crust one small porous clast was found to be very rich in volatile elements as well as in most lithophile and siderophile elements as this sample also contains abundant sulfides the enrichments could be related to element mobilization and redistribution by volatile sulfur species

the constitution and structure of the lunar interior the current state of understanding of the lunar interior is the sum of nearly four decades of work and a range of exploration programs spanning that same time period missions of the 1960s including the rangers surveyors and lunar orbiters as well as earth based telescopic studies laid the groundwork for the apollo program and provided a basic understanding of the surface its stratigraphy and chronology through a combination of remote sensing surface exploration and sample return the apollo missions provided a general picture of the lunar interior and spawned the concept of the lunar magma ocean in particular the discovery of anorthite clasts in the returned samples led to the view that a large portion of the moon was initially molten and that crystallization of this magma ocean gave rise to mafic cumulates that make up the mantle and plagioclase flotation cumulates that make up the crust smith et al 1970 wood et al 1970 this model is now generally accepted and is the framework that unifies our knowledge of the structure and composition of the moon the intention of this chapter is to review the major advances that have been made over the past decade regarding the constitution of the moon s interior much of this new knowledge is a direct result of data acquired from the successful clementine and lunar prospector missions as well as the analysis of new lunar meteorites as will be seen results from these studies have led to many fundamental amendments to the magma ocean model much of what we know from sample analyses has been previously summarized elsewhere and only their most important aspects will be discussed in this chapter the reader is referred to the relevant chapters in the books basaltic volcanism on the terrestrial planets basaltic volcanism study project 1981 the

towards balancing the oceanic ni budget abstract nickel isotopes are a novel and promising tracer of the chemistry of past ocean environments but realisation of this tracer s potential requires a comprehensive understanding of the controls on ni burial in the marine sedimentary archive an outstanding puzzle in the marine budget of ni first recognised in the 1970s is a major imbalance in the known inputs and outputs to and from the ocean the sedimentary outputs of ni are much larger than the inputs rivers dust much more recently it has also been recognised that the outputs are also considerably isotopically heavier than the inputs in this study we find light ni isotope compositions 60 ninist srm986 0 2 to 0 8 for mn rich sediments from the eastern pacific compared to fe mn crusts at about 1 6 these data suggest that diagenetic remobilisation of isotopically heavy ni leads to a significant benthic ni flux estimated at 0 6 2 3 10 8 mol yr similar in magnitude to the riverine flux to the ocean diagenetic remobilisation of ni may occur either via cycles of mn oxide dissolution and precipitation with associated ni sorption and release or during mineralogical transformation of birnessite to todorokite a minor role for retention of isotopically light ni by fe oxides or fe rich authigenic clays is also proposed overall a benthic flux of isotopically heavy ni at about 3 can balance the marine ni budget pinpointing diagenesis as a key missing piece of the ni puzzle

latest aspects of earthquake prediction in greece based on seismic electric signals ii abstract since 1983 continuous monitoring of the electrotelluric field has been carried out using an array of measuring stations located at various sites in greece the basic physical properties of the transient changes seismic electric signals ses in the electrotelluric field that are forerunners of earthquakes were first described six years ago since then a large body of data has been collected resulting in new insight into various aspects of the method the present paper reviews the latest developments in ses based earthquake prediction and describes the current procedures used to predict the epicenter and magnitude of an impending earthquake a detailed list of the predictions officially issued in greece during the past 3 years january 1 1987 november 30 1989 is also given public warnings were issued well before the most destructive seismic activity

mineralogical control on transition metal distributions in marine manganese nodules abstract electron microprobe and x ray diffraction data for north pacific manganese nodules reveal that the transition metal distributions are controlled by the mineralogy microlayers rich in 10a manganates generally have high mn fe ratios and positive correlations between ni cu and mn and between co and fe microlayers rich in vernadite on the other hand show low mn fe ratios and co ni and cu all show positive correlations with mn the 10a manganates form mainly in porewaters with high mn fe ratios the ni2 and cu2 ions are post depositionally incorporated into the interlayers of the manganates whereas co3 is substituted for fe3 in ferric oxyhydroxides in seawater with a low mn fe ratio on the other hand the adsorption of positively charged ferric oxyhydroxides on negatively charged mno6 octahedral layers suppresses the growth of 10a manganates enhancing the formation of vernadite positively charged hydroxides of co3 ni2 and cu2 are also adsorbed on the mno6 layers these mechanisms of mineral formation and metal uptake are corroborated by data for other oceanic non hydrothermal manganese nodules and crusts

the formation of todorokite and birnessite in sea water pumped from under ground abstract manganese oxides precipitated from aerated well sea water at the marine science museum tokai university have been analyzed chemically and mineralogically the o mn ratios are lower in todorokite than in birnessite but these minerals have similar contents of minor transition metals which can be taken up additionally from sea water after the precipitation of mn oxides on the basis of these results the genesis of mn minerals is discussed in relation to marine mn nodules

the magma ocean concept and lunar evolution the model of lunar evolution in which the anorthositic plagioclase rich oldest crust of the moon is formed over a period of 300 myr or less by crystallization as it floats on a global ocean of magma tens or hundreds of km thick is examined in a review of petrological and theoretical studies consideration is given to the classification of lunar rocks the evidence for primordial deep global differentiation constraints on the depth of the molten zone the effects of pressure on mineral stability relationships mainly liquid vs mainly magmifer ocean models and the evidence for multiple ancient differentiation episodes a synthesis of the model of primordial differentiation and its aftereffects is presented and the generalization of the model to the earth and to mars mercury venus and the asteroids is discussed

cogenetic rock fragments from a lunar soil evidence of a ferroan noritic anorthosite pluton on the moon abstract the impact that produced north ray crater apollo 16 landing site exhumed rocks that include relatively mafic members of the lunar ferroan anorthositic suite bulk and mineral compositions indicate that a majority of 2 4 mm lithic fragments from sample 67513 including impact breccias and monomict igneous rocks are related to a common noritic anorthosite precursor compositions and geochemical trends of these lithic fragments and of related samples collected along the rim of north ray crater suggest that these rocks derived from a single igneous body this body developed as an orthocumulate from a mixture of cumulus plagioclase and mafic intercumulus melt after the plagioclase had separated from any cogenetic mafic minerals and had become concentrated into a crystal mush 70 wt plagioclase 30 wt intercumulus melt we present a model for the crystallization of the igneous system wherein system is defined as cumulus plagioclase and intercumulus melt the initial accumulation of plagioclase is analogous to the formation of thick anorthosites of the terrestrial stillwater complex however a second stage of formation is indicated involving migration of the cumulus plagioclase intercumulus melt system to a higher crustal level analogous to the emplacement of terrestrial massif anorthosites compositional variations of the lithic fragments from sample 67513 are consistent with dominantly equilibrium crystallization of intercumulus melt the highly calcic nature of orthocumulus pyroxene and plagioclase suggests some reaction between the intercumulus melt and cumulus plagioclase perhaps facilitated by some recrystallization of cumulus plagioclase bulk compositions and mineral assemblages of individual rock fragments also require that most of the mafic minerals formed in close contact with cumulus plagioclase not as separate layers the distribution of compositions and by inference modes has a narrow peak at anorthosite and a broader larger peak at noritic anorthosite characteristics of the samples and their geochemical trends imply an origin in a system that was large relative to the unknown size of the impact that produced the brecccas of ferroan noritic anorthosite composition that were excavated later by the formation of north ray crater and they appear to be consistent with an origin of the suite within a perched plagioclase cumulate if the moon s crust formed by accumulation of plagioclase in a magma ocean ferroan noritic anorthosite formed as an orthocumulate is an alternative to extensive adcumulus formation of ferroan anorthosite 90 vol plagioclase this provides a relatively mafic ferroan anorthositic component 15 vol mafics which is required by mass balance models of compositions of polymict lunar crustal materials the inferred bulk composition of the system of cumulus plagioclase and intercumulus melt is similar to that of ferroan regolith breccia macalpine hills 88104 5 a lunar highland meteorite and may represent a common and widespread component of the moon s early highland crust

lunar granulites and their precursor anorthositic norites of the early lunar crust lunar granulites are breccias with metamorphic textures they are not pristine having been contaminated with meteoritic siderophiles nonetheless they constitute an abundant class of highlands rocks that are important because they are ancient and kreep free they may represent our best samples of the early lunar crust the granulites can be divided into ferroan and magnesian groups and each group can be subdivided on the basis of mineral composition and ree concentrations textural and compositional data show that some of the granulites especially 67215 and 67415 may be derived from distinct anorthositic norite precursors while some other granulites 79215 78155 are clearly polymict even the polymict granulites probably had anorthositic norites as their dominant precursors and not anorthosites norites or troctolites the granulites have compositions similar to those of the two lunar meteorites one of which yamato 791197 is ferroan the other alha81005 magnesian these meteorites are soil breccias from an unknown location distant from the apollo landing sites and contain anorthositic norites as abundant clasts compositions of granulites and lunar meteorites more closely resemble the average composition of lunar highlands as determined by remote sensing than do those of any other returned lunar samples the predominance of plutonic anorthositic norite precursors in material having the composition typical of highlands suggests that plutonic anorthositic norites were more abundant in the early lunar crust than is implied by their scarcity among pristine rocks from apollo missions

petrogenesis of ferromanganese nodules from east of the chagos archipelago central indian basin indian ocean abstract deep sea ferromanganese nodules occur over a large area and on many different sediment types of the central indian basin indian ocean selected samples were studied to determine their chemical and mineralogical compositions and microstructural features repeated laminations of variable thickness alternately dominated by todorokite and vernadite are characteristic of these nodules these laminae show on electron microprobe line scans corresponding interlaminar partitioning of mn cu ni and fe co the bulk chemical compositions of these nodules plot in both the hydrogenetic and early diagenetic fields on the fe mn ni cu co 10 ternary diagram the binary diagram depicting the covariation of mn ni cu against fe co shows two distinct parallel regression lines one delineated by nodules from terrigenous siliceous ooze and siliceous ooze terrigenous sediments and the other by nodules from red clay siliceous ooze red clay and calcareous ooze red clay an increasing diagenetic influence in the nodules with the nature of the host sediment types was observed in the sequence terrigenous siliceous ooze and red clay siliceous calcareous ooze red clay a negative correlation between mn fe ratio and co and a positive correlation between mn fe ratio and ni cu was established the nodules show dendritic laminated and globular microstructures formed by primary growth of fe mn oxide laminae depositional hiatuses in the primary microstructures indicate that the growth of these nodules was episodic the oxide laminations show extremely complex growth patterns scattered biogenic remains and mineral grains acted as accessory seeds for growth of oxide layers in addition to the main nuclei none of the primary microstructures can be uniquely linked to a particular growth process or growth rate radial cracks cutting across primary microstructures are often filled by todorokite of a later generation post depositional modifications of the nodules were largely controlled by accreted biogenic remains as indicated by their progressive dissolution with increasing depth from nodule surfaces their pseudomorphic replacement by todorokite and the later growth of phillipsite and todorokite in the microfossil molds the growth patterns of the in filled oxides are often controlled entirely by the cavity walls and are discordant with the primary growth fabric primary todorokite was recrystallized to coarser grains of different chemical composition later generation veins of todorokite cut across and chaotically disrupted primary laminae

probability of earthquake occurrence in greece with special reference to the van predictions the van earthquake predictions were made on the basis of seismic electric signals ses but the debate seems to be directed toward the statistical significance of the predictions from seismic data only accordingly applying a logistic regression model to seismicity we present our estimation of the probability of earthquake occurrence in greece the main purpose of our study is to examine whether or not we can find a specific seismicity pattern that can be used to considerably increase probability estimates our estimation of the probability of occurrence of an earthquake of ms 5 0 is less than 0 25 in all the cases that we have examined if we lower the threshold magnitude from 5 0 to 4 3 we can find cases in which the probability becomes as high as 0 75 comparable to the success rate of the van method estimated by hamada 1993 in these cases however such a high probability is due mostly to aftershocks and if aftershocks are removed from the data set the probability falls below 0 5

petrologic province maps of the lunar highlands derived from orbital geochemical data orbital and sample geochemical data from the lunar highlands are combined in variation diagrams to determine a the coincidence between the two data sets and b the geologic validity of extrapolating observed diagrammatic relations to an image format we examined three variation diagrams mg 100 mg mg fe molar versus th ti c ratio normalized to chondrites al versus mg th ti c and fe versus th ti c for the orbital data within each diagram we establish a petrologic classification based on the data s clustering or coincidence with sample compositions or both the spatial distributions of each diagram s classes are shown as petrologic units on color coded classification maps the mg th ti c diagram which is similar to the mg sm ti c diagram that has been used in sample studies is inferior to the al mg th ti c diagram in discriminating kreep from mg suite rock types the orbital geochemical spectrometers analyzed the regolith in which mg varies much less than al although the fe th ti c diagram shows a diverse distribution of orbital data similar to that shown by the al mg th ti c diagram it is unable to discriminate adequately between kreep and mg suite rock types the fe th ti c diagram is nonetheless very useful because of its greater areal coverage orbital and soil sample compositions of the four highland landing sites correspond in both the al mg th ti c and the fe th ti c data the diagrams show some units of virtually pure anorthosite and norite most units show the effects of mixing of pristine rock types in the regolith one unit which dominates the eastern limb and farside highlands has a composition so mafic that with the chosen end members it requires a 30 mare basalt component we interpret this to mean that the highlands experienced a significantly greater amount of mare volcanism before the end of heavy bombardment than has been previously suggested the average global composition of the highlands under the apollo groundtracks is that of anorthositic gabbro an average that has significant implications for the role of near global plagioclase fractionation in lunar crustal genesis our analysis has shown that the simultaneous use of orbital and sample geochemical data in variation diagrams can 1 bridge the mechanical gap between orbital and sample studies by relating orbital data to sample petrology 2 present the results of several elemental databases as one map for rapid geologic analysis and 3 display quantitative mixing relations of different crustal materials in a spatial format this technique will be valuable for petrologic interpretation of the global geochemical data to be received from the future lunar geosciences orbiter mission

sorption of ni by birnessite equilibrium controls on ni in seawater abstract synthetic hexagonal birnessite hx birnessite is a close analogue to natural poorly crystalline phyllomanganate phases found in soils and marine ferromanganese deposits these phases are often highly enriched in trace metals such as ni and co we measured the sorption of ni ii onto synthetic hexagonal birnessite hx birnessite from ph 1 to 7 exafs spectra show that at ph 3 7 ni is adsorbed to the hx birnessite surface above vacancy sites on 001 as a tridentate corner sharing complex we developed a surface complexation model for ni adsorption based on the equilibria 3 mn 2 o 2 3 ni 2 mn 2 o 3 ni 0 3 mn 2 o 2 3 ni 2 h 2 o mn 2 o 3 ni oh h using this surface complexation model we predict the concentration of ni in seawater in equilibrium with ni bearing birnessite found in hydrogenetic femn crusts and nodules our predicted results are in good agreement with observed ni concentrations in seawater and suggest that the concentration of dissolved ni in seawater is buffered by sorption to birnessite or a related mno 2 phase however in addition to the surface complex ni also sorbs by structural incorporation into the vacancy site in our synthetic samples at ph 7 exafs shows 10 of ni is structurally incorporated into hx birnessite in natural birnessites found in marine ferromanganese crusts and nodules exafs shows that all of the sorbed ni is structurally incorporated structural incorporation suggests that ni sorption may be irreversible

structural stability of marine 10 a manganates from the ogasawara bonin arc implication for low temperature hydrothermal activity abstract hydrothermal 10 a manganate deposits with distinct differences in structural stability when exposed to air were found on the kaikata seamount of the ogasawara arc western pacific the most stable 10 a manganates are concentrated near the center of the hydrothermal field while the unstable ones occur towards the field margins all manganates are characterized by very high mn fe ratios and extremely low contents of transition elements such as cu co and ni the variation in 10 a stability of the hydrothermal manganates is not regulated by mineral chemistry or aging but appears to be determined by other factors e g the hydrothermal fluid temperature at mineral deposition we propose a structural model for marine manganates showing two continuous series of increasingly stabilized 10 a manganates one series is of hydrothermal origin structurally similar to todorokite with a tunnel structure fixed at deposition and the other is a buserite like series of diagenetic origin comprising phyllomanganates all the marine 10 a manganates can be progressively stabilized in two different manners the todorokite like series by the establishment of smaller tunnels and the buserite like series by post depositional uptake of 10 a stabilizing interlayer cations both series are linked together with a common end member the most unstable 10 a manganate which appears to be formed at low temperature and easily transforms to a 7 a manganate in air

magmatic evolution of lunar highland rocks estimated from trace elements in plagioclase a new bulk silicate moon model with sub chondritic ti ba sr ba and sr al ratios abstract the compositions of host magmas of ferroan anorthosites fan host magmas were estimated from secondary ion mass spectrometry analyses of plagioclase in lunar highland rocks the evolution of the magmas was investigated by considering phase relations based on the melts algorithm and by re examining partition coefficients for trace elements between plagioclase and melts data little affected by post magmatic processes were selected by using plagioclase with relatively primitive sc and co contents the fan host magma contained 90 174 ppm sr 40 119 ppm ba and 0 5 1 3 tio2 and had sub chondritic sr ba and ti ba ratios it is difficult to account for the formation of fan host magma on the basis of magma evolution processes of previously proposed bulk silicate moon models with chondritic ratios for refractory elements at global scale therefore the source of the fan host magma must have had primordial sub chondritic sr ba and ti ba ratios the fan host magmas were consistent in refractory elements with the estimated host mafic magma for feldspathic crust based on lunar meteorites and some very low ti mare rocks from lunar meteorites here we propose an alternative bulk silicate moon model the cbsm model which is enriched in crustal components of proto bodies relative to the present whole earth moon system

composition and evolution of the lunar crust in the descartes highlands apollo 16 samples from the north ray crater ejecta blanket apollo 16 were investigated by petrographic microscope electron microprobe instrumental neutron activation and xray fluorescence analyses and 40ar 39ar and rb sr dating techniques nine major groups of monomict and polymict breccias were defined on the basis of microscopic texture and these were further subdivided into chemical subgroups on the basis of characteristic elements such as al mg fe cr ree ni and co the polymict breccias fragmental breccias granulitic breccias and impact melt breccias are the result of multiple impact induced mechanical mixing and melting and of thermal and impact metamorphism of rock and mineral clasts derived from primordial igneous crustal rocks for calculations of mixing models it was found that end members consisting of the pristine igneous rock components present as discrete samples at the apollo 16 site and supplemented by kreep dunite and a meteoritic component yield the best fits for the composition of polymict breccias the end member rocks a re ferroan anorthosite various magnesian gabbronorites including sodic ferrogabbro and feldspathic lherzolite and spinei troctolite the following model is proposed for the composition and stratigraphy of the target for north ray crater the lower section of the stratigraphy is composed of a megabreccia with clasts of highly feldspathic polymict breccias kreep free old eastern highland rock suite interpreted as nectaris ejecta descartes formation the top section contains kreep bearing polymict breccias kreep bearing young western highland rock suite and appears to be similar to the lithologies found in the cayley plains this material interpreted as cayley formation may be a distant facies of imbrium basin ejecta deposits of the imbrium basin the petrographic differences between these two major selenographic units the descartes and the cayley formations in the apollo 16 area are more distinct than the chemical differences the petrographic and chemical composition of the primordial igneous upper crust in the regions of the nectaris and imbrium basins has been calculated by subtraction of the kreep and meteoritic components from the bulk composition of the descartes and cayley materials the nectaris crust which is better constrained consists of 86 87 a northosite 4 sodic ferrogabbro 0 5 1 3 feldspathic lherzolite 6 8 regular magnesian gabbronorite 1 8 2 8 dunite and 0 1 spinel troctolite a model for the evolution of the upper lunar crust in the descartes highlands is proposed on the basis of isotope ages and clast matrix relationships of polymict breccias essential features of this model in sequenial order are 1 development of multiple layers of kreep free early feldspathic fragmental megabreccias and impact melt sheets on the primordial crust in the time period from 4 4 aeons to the time of the nectaris impact which could have occurred as late as 3 85 aeons ago 2 excavation of these megabreccias by the nectaris event and deposition of a nectarian feldspathic fragmental megabreccia in the descartes area 3 introduction of kreep basaltic material into the upper crust mainly west and northwest of the descartes site and formation of kreepy impact melt sheets most probably from 4 05 to 3 80 aeons ago 4 imbrium impact at 3 8 aeons ago and deposition of kreep bearing imbrian feldspathic fragmental breccias at the descartes site which form the cayley formation and 5 redeposition mixing and melting of all preexisting breccias yielding kreep bearing and kreep poor post cayley fragmental breccias and melt ejecta glass bombs as the result of small impacts craters 1 5 km in diameter in the cayley plains and the descartes mountains respectively

evolved mare basalt magmatism high mg fe feldspathic crust chondritic impactors and the petrogenesis of antarctic lunar breccia meteorites meteorite hills 01210 and pecora escarpment 02007 antarctic lunar meteorites meteorite hills 01210 and pecora escarpment 02007 are breccias that come from different regolith lithologies on the moon met 01210 is composed predominantly of fractionated low ti basaltic material and is classified as an immature predominantly basaltic glassy matrix regolith breccia pca 02007 is a predominantly feldspathic regolith breccia consisting of metamorphosed feldspathic noritic troctolitic and noritic anorthosite clasts agglutinate and impact glasses as well as a number of basaltic clasts with mare and possible non mare affinities the basalt clasts in met 01210 have undergone fenner trend enrichments in iron and may also have witnessed late stage crystallization of zircon or a zirconium rich mineral some of the features of met 01210 are similar to other basaltic lunar breccia meteorites e g northwest africa 773 elephant moraine 87521 96008 yamato 793274 981031 but it is not paired with them the presence of metamorphic anorthositic clasts as well as agglutinates indicates a small regolith component similarities with previously discovered evolved e g lapaz icefield 02205 northwest africa 032 and ferroan e g asuka 881757 yamato 793169 basaltic lunar meteorites suggest a similar mare source region for met 01210 despite lack of evidence for pairing pca 02007 shares many features with other feldspathic regolith breccias e g yamato 791197 queen alexandra range 94281 including a high mg fe whole rock composition glass spherules agglutinate fragments and a diverse clast inventory spanning the range of ferroan anorthosite and high magnesium suite rocks some of the basalt fragments in this sample are fractionated and have an igneous origin however the majority of the basalt fragments are impact melt clasts pca 02007 supports previous studies of feldspathic lunar meteorites that have suggested an aluminous crust for the moon with compositions more similar to magnesium granulite breccias than ferroan anorthosites a chondrule like fragment found in pca 02007 and unlike any previously described lunar material is described and tentatively identified as the remnants of a chondritic lunar impactor this clast is porphyritic with equant olivines that have forsterite rich cores fo 98 extreme normal zonation to more fayalitic rims fo 44 and a mineral assemblage with rare earth element abundances distinct from described lunar material and more similar to chondrules found in ordinary or carbonaceous chondrites its discovery and description is significant for understanding the composition of lunar impactors previously the main evidence for chondritic lunar impactors was from chondritic relative abundances and near chondritic ratios of highly siderophile elements in lunar impact melt breccias however the presence of this clast along with two other chondritic clasts from apollo soils 12037 and 15602 provides clues to the identity of ancient meteorite impactors on the moon

hrtem investigation of trilling todorokite and nano phase mn oxides in manganese dendrites we characterized manganese dendrites on three different substrate rocks rhyolite clayey siltstone and limestone using high resolution transmission electron microscopy manganese dendrites are mainly composed of nanometer scale mn hydr oxides fe oxy hydroxide sulfate and clay minerals including hollandite todorokite birnessite goethite amorphous fe hydroxide smectite illite and gypsum each sample has a different main manganese phase two dendrite samples have more than one manganese phase todorokite crystals on a limestone sample from altmuhl valley germany showed trilling intergrowths chain width disorder and chain termination occur in todorokite the sum of the numbers of octahedral wall layers and octahedral chains were equal at both sides beyond the termination the chain termination rule was explained by the geometry of octahedral chains and the octahedral wall layer the trilling intergrowths of todorokite might be formed by transforming the structure from birnessite to todorokite or by multiple epitaxial todorokite nucleations on octahedral wall layer of todorokite or birnessite based on chain width disorder in the todorokite we suggest that the todorokite might have been transformed from birnessite

an ancient sm nd age for a ferroan noritic anorthosite clast from lunar breccia 67016 strontium and neodymium systematics have been examined in a clast of ferroan noritic anorthosite from apollo 16 breccia 67016 two splits 328 and 326 of the same clast give different sm nd results split 328 gives a well defined internal isochron age of 4 562 0 068 ga and an initial 143nd 144nd ratio of 0 50673 10 corresponding to nd 0 1 0 2 2 optimized error relative to the murchinson carbonaceous chondrite the pyroxene separate from split 326 lies on the same isochron in contrast the plagioclase and whole rock from split 326 fall below this line indicating a small scale disturbance of the sm nd system this may reflect either an isotopic exchange between the plagioclase and a low sm nd mineral or a loss of radiogenic 143nd from the plagioclase possibly during the period of major impacts at 3 9 ga the preservation of an extremely old age for the noritic ferroan anorthosite 67016 328 suggests a rapid cooling of this rock at an early stage in the evolution of the lunar magma ocean this old age is also consistent with giant impact models for the formation of the moon but implies a relatively early event pre 4 50 ga and therefore rapid accretion and differentiation of the terrestrial planets

anatexis of lunar cumulate mantle in time and space clues from trace element strontium and neodymium isotopic chemistry of parental apollo 12 basalts abstract in an effort to elucidate the processes of lunar mantle melting and the magma evolution of mare basalts within oceanus procellarum on the western lunar near side we have analyzed seven fine grained to vitrophyric apollo 12 basalts for trace elements five of these also have been analyzed for nd and sr isotopic compositions these samples represent all three main groups identified among the apollo 12 mare basalts and have been proposed as parental melts to their respective groups i e olivine pigeonite and ilmenite basalts the sources for these low ti mare basalts are postulated to have formed from crystallization of a global magma ocean li be systematics combined with ree data indicate that the specific sources for the apollo 12 low ti mare basalts were generated after 82 94 crystallization of this lunar magma ocean in fact it seems that all mare basalts analyzed from the apollo collections were generated from cumulates precipitated in the last 20 of the magma ocean chemical compositions of fine grained pigeonite and olivine basalts are consistent with 7 9 nonmodal in proportions not defined by experimental petrology and phase equilibria melting of a source consisting of 48 olivine 30 calcic clinopyroxene and 22 pigeonite as per neal et al 1994b sm nd and rb sr abundance data also suggest that the pigeonite and olivine basalt source contained from 0 3 to 0 5 trapped residual liquid from the magma ocean the compositions of the two fine grained ilmenite basalts are consistent with 5 7 partial melting of a source with subequal proportions of olivine 45 5 and pigeonite 42 5 and lesser amounts of clinopyroxene 11 5 and entrained plagioclase 0 5 furthermore the ilmenite source was nearly devoid of trapped liquid isotopic systematics of the apollo 12 fine grained parental basalts are consistent with their derivation from two distinct mantle source regions both of these sources were lree depleted for extended periods of time up to 600 million years for the ilmenite basalt source and up to 900 million years for the pigeonite and olivine basalt source due in part to the relatively small proportion of low sm nd trapped residual magma ocean liquid in the source by integrating this information on parental low ti apollo 12 basalts with mare basalt and picritic glass data from other landing sites as well as telescopic and remote sensing data we propose a model for melting of the lunar interior the upper 400 500 km of the lunar mantle is a consequence of incipient melting of the moon and formation of a global magma ocean this magma ocean became progressively enriched in incompatible elements as it precipitated the cumulate upper mantle this incompatible earliest extensive mare magmas high ti mare basalts were generated at shallow depths in the mantle from cumulate source regions that had trapped relatively large proportions of this incompatible element enriched residual magma ocean liquid these source regions also contained the late crystallizing phase ilmenite and thus generated high ti magmas the trapped liquid component contained elevated abundances of heat producing elements k u and th increasing the fertility of associated source regions with time melting moved progressively deeper in the mantle to source regions with less of the residual heat producing magma ocean liquid due to density contrasts the ilmenite bearing upper portions of the lunar mantle sank into the cumulate pile possibly carrying more fertile material with it and allowing melting of more mg enriched source regions to form the high ti picritic glass beads thus the major controlling factors in the melting of the lunar interior could be the proportion of trapped magma ocean liquid in the cumulate source and the sinking of more fertile ilmenite bearing material into the lower mantle

electromagnetic precursors to earthquakes in the ulf band a review of observations and mechanisms despite over 2 decades of international and national monitoring of electrical signals with the hope of detecting precursors to earthquakes the scientific community is no closer to understanding why precursors are observed only in some cases laboratory measurements have demonstrated conclusively that self potentials develop owing to fluid flow and that both resistivity and magnetization change when rocks are stressed however field experiments have had much less success many purported observations of low frequency electrical precursors are much larger than expectations based on laboratory results in some cases no precursors occurred prior to earthquakes or precursory signals were reported with no corresponding coseismic signals nonetheless the field experiments are in approximate agreement with laboratory measurements maximum resistivity changes of a few percent have been observed prior to some earthquakes in china but the mechanism causing those changes is still unknown anomalous electric and magnetic fields associated with fluid flow prior to earthquakes may have been observed finally piezomagnetic signals associated with stress release in earthquakes have been documented in measurements of magnetic fields

fe mn oxyhydr oxides as an indicator of rey enrichment in deep sea sediments from the central north pacific abstract nowadays pelagic sediments are globally explored as a potential resource of rare earth elements and yttrium termed as rey and have received unprecedented attention however the formation mechanism of rey rich deep sea mud remains controversial the fe mn oxyhydr oxides are ubiquitous in oxic marine sediments and potentially beneficial for the rey enrichment the research of them is important for understanding the ore formation of rey rich mud and thus can help to evaluate the role of marine sediments in global rey cycles in this contribution using advanced in situ analytical techniques we provide new results on the nanoscale mineralogy and geochemistry of fe mn oxyhydr oxides that are recovered from rey rich deep sea sediments in central north pacific ocean in situ x ray diffraction analyzer and scanning electron microscope reveal that the fe mn minerals e g vernadite birnessite and todorokite occur as overgrowths on the surface of nuclei to form fe mn micronodules transmission electron microscope tem imaging reveals that these fe mn minerals are composed of nanocrystals with high intercrystalline porosity indicating a potential strong adsorption capacity the tem observations also imply a mineral phase transformation from birnessite vernadite to todorokite during the oxic diagenesis accompanied by corresponding changes in geochemical compositions laser ablation inductively coupled plasma mass spectrometry demonstrates that fe mn oxyhydr oxides contain high rey concentrations varying from 439 to 1 654 ppm with an average of 790 ppm and can be regarded as an important host of rey furthermore the paas normalized and seawater normalized rey patterns both infer that the rey contents of fe mn oxyhydr oxides are ultimately derived from seawater and characterized by preferential scavenging of ce overall fe mn oxyhydr oxides not only contribute a moderate proportion of rey but also provide specific information for understanding geochemical processes related to rey enrichment in deep sea sediments

exceptional preservation of mn oxidizing microbes in cave stromatolites el soplao spain abstract many ferromanganese stromatolites of el soplao cave n spain are characterized for the exceptional preservation and high diversity of microbial fossils probably representing the best example of microbial preservation described in ferromanganese deposits so far the el soplao stromatolites are mainly formed by polymetallic mn rich oxides with subordinate and variable amounts of detrital material and consist of both dendritic and laminar microfacies in both microfacies microbial forms are abundant in the relatively pure mn oxide rich material whereas they are scarce in areas with significant detrital material microbial forms are observed either in cross section completely embedded in the mn oxide rich matrix or in three dimensions lining the walls of pores based on their morphology we have separated the most abundant microbial forms into six main morphotypes and six additional submorphotypes most of which can be assigned to bacteria most morphotypes consist of coccoid coccobacilus or filamentous forms therefore they are not diagnostic of any particular bacterial group however the ovoid cells of morphotype b show cylindrical polar protuberances typical of prosthecate alpha proteobacteria on the basis of characteristic morphological features three submorphotypes of morphotype b can be assigned to three alpha proteobacteria genera hyphomicrobium pedomicrobium and caulobacter this ascription is supported by the well known mn oxidizing behavior of both pedomicrobium and caulobacter and by the common presence of hyphomicrobium in ferromanganese deposits elsewhere the excellent microbial preservation is partly related to the origin of the ferromanganese oxides i e extracellular precipitation induced by microbial metabolism other factors contributing to the good microbial preservation are the relatively low degree of diagenetic alteration and the relatively high accretion rates of stromatolites compared to other ferromanganese deposits the generally low degree of diagenesis is likely because the stromatolites have remained relatively stable and at a rather low temperature since they were formed at least 1 ma ago still some stromatolites have suffered diagenetic alteration partial dissolution and replacement by calcium carbonates and fe rich oxides obscuring or even obliterating their bioforms the el soplao case represents an example of how easily biogenic mn oxides can be altered and their bioforms blurred in a relatively short geological time span in spite of being in a relatively stable alkaline and low temperature setting a geological implication is that the absence of bioforms in other ferromanganese deposits including rock varnish and precambrian iron formations does not disprove their possible biogenic origin since the high chemical reactivity of biogenic manganese oxides makes them highly vulnerable to diagenesis

additional complexity in the lunar crust petrology of sodic anorthosites and sulfur rich ferroan noritic anorthosites lunar breccia 67016 contains two suites of unusual highlands rocks sulfur rich noritic anorthosites and sodic anorthosites mineral compositions of the sulfur rich noritic anorthosites closely match those of ferroan anorthosites unusually large amounts of sulfides and sulfidation reactions involving olivine in these clasts probably reflect endogenous volatile transfer the sodic anorthosites are mafic poor with mineral compositions intermediate between those of pristine ferroan and alkali anorthosites rare examples of pristine rocks with similar mineral compositions are known and may represent a distinct class of lunar crustal rocks

ni cu co rich hydrothermal manganese mineralization in the wallis and futuna back arc environment sw pacific abstract the wallis and futuna back arc system is a complex area composed of at least two active oceanic spreading centers the futuna and alofi spreading centers and young volcanic zones characterized by diffuse magmatism locally affected by the samoan hotspot this geological setting is favorable to the establishment of hydrothermal systems in the form of either high temperature ht hydrothermal venting or low temperature lt diffuse flow during the 2010 futuna cruise aboard the r v l atalante three remarkable inactive lt fe si mn deposits were discovered utu uli anakele and utu sega some of the mn rich precipitates discovered exhibit the highest base metals concentrations so far recorded in ferromanganese rocks including in the well documented hydrogenetic crusts and polymetallic nodules the deposits lie on top of volcanoes and formed in close association with the volcanic facies the manganese mineralization occurs in the form of massive layered crusts and mn rich cements within strongly altered basaltic pyroclastic rocks brecciated lavas and more rarely in sediments field observations and mineralogical and chemical studies support a hydrothermal origin for the mineralization and show that nickel cobalt and copper enrichments are controlled by the precipitation of 7 a and 10 a manganates the conventional geochemical classifications e g bonatti et al 1972 used to decipher the origin of mn mineralization cannot be used for this new type of deposit and new robust discrimination diagrams need to be established we suggest that the unusual enrichment of metals recorded in our samples is due to i a lack of precipitation of high temperature massive sulfides at depths that would have retained metals e g cu ni co ii isolation of the hydrothermal system thereby avoiding ni co and cu losses in the water column and iii the ability of birnessite and buserite todorokite to scavenge co ni and cu from aqueous fluids the utu uli and anakele deposits share certain characteristics with the active hydrothermal system at loihi seamount e g the depth of mineralization relationships with pyroclastic volcanoes and the influence of a mantle plume source and thus might represent late stage products of this specific type of hydrothermal activity elsewhere the co rich mineralization of the calatrava volcanic field cvf in spain may be a potential analog of the utu sega deposit the mn co deposits of the cvf formed in close proximity to pliocene volcanic rocks metals were transported by epithermal hydrothermal solutions with high fo 2 and cobalt was scavenged by mn oxides together with the well documented stratabound mn deposits gonzalez et al 2016 hein et al 2008 hein et al 1996 the mn deposits discovered in the wallis and futuna back arc provide crucial insights into lt hydrothermal activity in the deep ocean the metal rich character of this lt hydrothermal activity may be of major importance for future research on the net flux of hydrothermally derived metals e g ni co cu to the open ocean

geochemical studies of feldspathic fragmental breccias and the nature of north ray crater ejecta major and trace element analyses of clasts and matrix from feldspathic fragmental breccias show that these breccias are not all alike but vary widely in their bulk compositions and clast assemblages these studies together with analyses of other north ray crater large rocks reveal the major components to be anorthosites ferroan anorthositic norites magnesian granulites feldspathic melt rocks and vha impact melts the ferroan anorthositic norites are important lunar crustal rocks identified here for the first time the kreepy vha melts are found to be much more important in north ray crater ejecta than was previously assumed sodic ferrogabbro is an important minor component the compositional characteristics of bulk breccias and feldspathic melt rocks are modeled quantitatively as mixtures of two to five components anorthosites ferroan anorthositic norites magnesian granulites sodic ferrogabbros and vha melt rocks breccia 67455 is unique in consisting wholly of ferroan kreep free components

geochemistry of lunar crustal rocks from breccia 67016 and the composition of the moon global differentiation of the moon has produced a plagioclase rich crust overlying an ultramafic mantle we have conducted a major and trace element study of anorthositic clasts from an apollo 16 breccia to investigate the geochemical features of these highlands lithologies and their role in lunar crustal evolution samples analyzed for this study have aluminous alkali poor compositions and varied feo and mgo contents al2o3 25 35 na2o 0 3 1 k2o 1 ferroan noritic and 1 magnesian troctolitic respectively these mafic enriched varieties have considerably higher lithophile element concentrations at levels similar to that of the bulk lunar crust the ferroan noritic clasts may represent a fundamental type of igneous rock in the lunar crust which has not been widely recognized liyb ratios of highlands and mare rocks demonstrate the complementary nature of the lunar crust and mantle which is best explained by a global differentiation event such as crystallization of a magma ocean the most primitive mantle derived lunar material for which data are available the apollo 15 green glass has liyb virtually identical to those of the mafic enriched anorthosites providing an estimate of the magma ocean composition the moon and the earth have liyb ratios that are similar to each other but the absolute abundances of both li and yb appear to be higher in the moon the liyb ratios of the earth and moon are distinct from those of ci and ordinary chondrites and the eucrite parent body but are similar to those of cv co and el chondrites precluding a unique match between the composition of the earth and moon

mineralogy and crystal chemistry of mn fe co ni and cu in a deep sea pacific polymetallic nodule minor element concentrations in marine ferromanganese nodules are primarily controlled by the mineralogy which itself depends on redox conditions at the sediment water interface results are presented for the first in depth x ray microstructural and microspectroscopic investigation of a mixed hydrogenetic diagenetic nodule which is representative of ferromanganese deposits on abyssal plains the measurements were conducted by micro x ray diffraction and x ray absorption spectroscopy both xanes and exafs on hydrogeneous and diagenetic regions of the nodule the hydrogenetic diagenetic interface was imaged by x ray microfluorescence after which regions of interest were chosen to represent mineralogical and chemical transformations that occurred at the early stage of suboxic diagenesis in the hydrogenetic nodule oxic environment mn is speciated as fe vernadite a nanocomposite material composed of intergrown feroxyhite feooh and monodispersed phyllomanganate layers having no interlayer mn vernadite in the diagenetic nodule suboxic environment mn is speciated dominantly as mg rich 10 a vernadite which consists of a random intergrowth of vernadite and its transformation product todorokite the authigenic 10 a vernadite precipitated from the components of vernadite in fe vernadite that were dissolved in suboxic microenvironments of the sediment direct evidence supporting a redox driven dissolution reaction is provided by the valence composition of mn as measured by micro xanes which is 0 69mn4 0 24mn3 0 07mn2 average 3 62 0 04 v u for fe vernadite and 0 61mn4 0 23mn3 0 16mn2 average 3 28 0 04 v u for 10 a vernadite ni and cu derived mainly from dissolved vernadite and oxidized organic matter replace structural mn3 4 in both the mno2 layer and todorokite domains of 10 a vernadite pure todorokite in highly diagenetic regions of the nodule has an average formula of mg2 0 167 mn4 0 783 mn3 0 099co3 0 002ni2 0 076cu2 0 040 o2 n h2o with an atomic ratio of cu ni co mn 0 13 which is slightly lower than 0 167 1 6 the maximum metal uptake capacity reported for marine nodules by analogy with synthetic todorokites we infer that mg2 which has a hydrated diameter close to that of the 3 3 tunnel size of todorokite and mn3 and cu2 which prefer jahn teller distorted octahedra play a crucial role in templating the topotactic transformation of 10 a vernadite to todorokite and stabilizing todorokite in suboxic marine sediments

iron mineral structure reactivity and isotopic composition in a south pacific gyre ferromanganese nodule over 4ma abstract deep sea ferromanganese nodules accumulate trace elements from seawater and underlying sediment porewaters during the growth of concentric mineral layers over millions of years these trace elements have the potential to record past ocean geochemical conditions the goal of this study was to determine whether fe mineral alteration occurs and how the speciation of trace elements responds to alteration over 3 7 ma of marine ferromanganese nodule mfn formation a timeline constrained by estimates from 9be 10be concentrations in the nodule material we determined fe bearing phases and fe isotope composition in a south pacific gyre spg nodule specifically the distribution patterns and speciation of trace element uptake by these fe phases were investigated the time interval covered by the growth of our sample of the nodule was derived from 9be 10be accelerator mass spectrometry ams the composition and distribution of major and trace elements were mapped at various spatial scales using micro x ray fluorescence xrf electron microprobe analysis empa and inductively coupled plasma mass spectrometry icp ms fe phases were characterized by micro extended x ray absorption fine structure exafs spectroscopy and micro x ray diffraction xrd speciation of ti and v associated with fe was measured using micro x ray absorption near edge structure xanes spectroscopy iron isotope composition 56 54fe in subsamples of 1 3 mm increments along the radius of the nodule was determined with multiple collector icp ms mc icp ms the spg nodule formed through primarily hydrogeneous inputs at a rate of 4 0 0 4 mm ma the nodule exhibited a high diversity of fe mineral phases feroxyhite feooh goethite feooh lepidocrocite feooh and poorly ordered ferrihydrite like phases these findings provide evidence that fe oxyhydroxides within the nodule undergo alteration to more stable phases over millions of years trace ti and v were spatially correlated with fe and found to be adsorbed to fe bearing minerals ti fe and v fe ratios and ti and v speciation did not vary along the nodule radius the 56 54fe values when averaged over sample increments representing 0 25 0 75 ma were homogeneous within uncertainty along the nodule radius at 0 12 0 07 2sd n 10 our results indicate that the fe isotope composition of the nodule remained constant during nodule growth and that mineral alteration did not affect the primary fe isotope composition of the nodule furthermore the average 56 54fe value of 0 12 we find is consistent with fe sourced from continental eolian particles dust despite mineral alteration the trace element partitioning of ti and v and fe isotope composition do not appear to change within the sensitivity of our measurements these findings suggest that fe oxyhydroxides within hydrogenetic ferromanganese nodules are out of geochemical contact with seawater once they are covered by subsequent concentric mineral layers even though fe bearing minerals are altered trace element ratios speciation and fe isotope composition are preserved within the nodule

high resolution la icp ms mapping of deep sea polymetallic micronodules and its implications on element mobility abstract enrichments of rey rare earth yttrium and other trace metals co and ni in deep sea ferromanganese fe mn micronodules have received increasing attention in both deep sea research and mineral exploration due to the presence of multiple easily crushed and poorly crystallized phases in micronodules the genesis of micronodules and their adsorption of various trace elements are poorly understood to address this gap we examined the spatial distributions of elements in cross sections of micronodules from the western tropical north pacific ocean using high resolution hr la icp ms raster mapping coupled with laser raman and x ray photoelectron spectroscopy xps the ferromanganese micronodules we studied are dominated by fe and mn oxides with minor carbonate minerals such as siderite rhodochrosite and calcite la icp ms maps show that these micronodules consist of a mn rich core and a fe rich rim the fe enriched rim is enriched in as and surrounds a mg mn cu co and ni concreted core laser raman maps show that the micronodule core contains more birnessite an important scavenger of trace metals in deep sea sediments than the rim the birnessite filled core of these micronodules does not have elevated rey indeed birnessite line channels may feed metal rich fluid containing rey to adjacent minerals including well crystallized bio apatite and zeolite as high ce and y levels are spatially correlated with these minerals the observed element profiles and xps observations showing the coexistence of multiple oxidation states of mn 2 3 and 4 fe 2 and 3 and ce 3 4 demonstrate that the fe mn phases of these micronodules are of a diagenetic origin and that they are sites of redox driven metal enrichment in deep sea sediment

the relationship between manganese minerals and metallic elements in deep sea manganese nodules abstract the relationship between manganese minerals and the concentration of fe cu ni zn and al in mn rich crystalline areas in deep sea manganese nodules were investigated using microdiffraction and electron microprobe analysis thirty three microsamples were obtained from eight polished sections of five pacific ocean manganese nodules birnessite and todorokite are the principal manganese minerals in the x ray diffraction powder patterns on polished sections kept in a vacuum only birnessite was identified in sixteen microsamples only todorokite was identified in one microsample another sixteen microsamples were mixtures of birnessite and todorokite microsamples in which only birnessite was identified contain cu ni and zn in the same concentrations as the microsamples in which both birnessite and todorokite were identified it appears that birnessite as well as todorokite can incorporate cu ni and zn with the exception that no todorokite was observed in microsamples with very small amounts of fe cu and ni there is no systematic correlation between the manganese mineralogy and the concentration of fe cu ni and zn in the microsamples the microsamples examined in this study contain varying amounts of al 0 01 2 57 wt 0 92 wt on average todorokite appeared in the microsamples which contained more than 0 7 wt al mineralogical considerations suggest that at least part of the al detected may be incorporated in todorokite

statistical evaluation of the ses predictions issued in greece alarm and success rates earthquake prediction based on continuous measurements of the electric field of the earth has been systematically carried out by varotsos and co workers in greece predictions were issued by telegrams to greek authorities statistical evaluation of these predictions was made by comparing telegram prediction information with earthquake parameters determined by the us geological survey the space time domain selected for this evaluation was 20 24 e 36 41 n from january 1987 to june 1989 successfully predicted earthquakes are defined here as those that occurred within 22 days of the prediction within 100 km of the predicted epicenter and with a magnitude difference predicted minus true rot greater than 0 7 twelve predictions were issued for earthquakes with expected ms 5 3 following our criteria ten were successful two were not the magnitudes of the predicted earthquakes varied from 4 1 to 5 5 for earthquakes with mb usgs 5 0 the ratio of the predicted to the total number of earthquakes is 6 12 50 and the success rate of the prediction is also 612 50 with a probability gain of a factor of 4 with a confidence level of 99 8 the possibility of this success rate being explained by a random model of earthquake occurrence taking into account a regional factor which includes high seismicity in the prediction area can be rejected for earthquakes with mb usgs 4 5 a statistical significance could not be obtained because of the large number of small earthquakes

chronology geochemistry and petrology of a ferroan noritic anorthosite clast from descartes breccia 67215 clues to the age origin structure and impact history of the lunar crust the petrology major and trace element geochemistry and nd ar sr isotopic compositions of a ferroan noritic anorthosite clast from lunar breccia 67215 have been studied in order to improve our understanding of the composition age structure and impact history of the lunar crust the clast designated 67215c has an unusually well preserved igneous texture mineral compositions are consistent with classification of 67215c as a member of the ferroan anorthositic suite of lunar highlands rocks but the texture and mineralogy show that it cooled more rapidly and at shallower depths than did more typical ferroan anorthosites fans incompatible trace element concentrations are enriched in 67215c relative to typical fans but diagnostic signatures such as ti sm sc sm plagiophile element ratios and the lack of zr hf and nb ta fractionation show that this cannot be due to the addition of kreep alternatively 67215c may contain a greater fraction of trapped liquid than is commonly present in lunar fans 147sm 143nd isotopic compositions of mineral separates from 67215c define an isochron age of 4 40 0 11 gyr with a near chondritic initial 143nd of 0 85 0 53 the 40ar 39ar composition of plagioclase from this clast records a post crystallization thermal event at 3 93 0 08 gyr with the greatest contribution to the uncertainty in this age deriving from a poorly constrained correction for lunar atmosphere 40ar rb sr isotopic compositions are disturbed probably by the same event recorded by the ar isotopic compositions trace element compositions of fans are consistent with crystallization from a moderately evolved magma ocean and do not support a highly depleted source composition such as that implied by the positive initial 143nd of the ferroan noritic anorthosite 62236 alternatively the nd isotopic systematics of lunar fans may have been subject to variable degrees of modification by impact metamorphism with the plagioclase fraction being more strongly affected than the mafic phases 147sm 143nd isotopic compositions of mafic fractions from the 4 ferroan noritic anorthosites for which isotopic data exist 60025 62236 67016c 67215c define an age of 4 46 0 04 gyr which may provide a robust estimate for the crystallization age of lunar ferroan anorthosites

oxidative scavenging of thallium by birnessite explanation for thallium enrichment and stable isotope fractionation in marine ferromanganese precipitates tl stable isotopes recorded in marine ferromanganese crusts show great promise as a tracer of past marine and climatic conditions key to interpreting recent tl stable isotope time series data is a detailed molecular level understanding of tl scavenging by ferromanganese crust minerals and tl stable isotope fractionation occurring during uptake to this end we determine the mechanism of tl sorption to the primary ferromanganese minerals in crusts namely hexagonal birnessite todorokite and ferrihydrite using xas we compliment our data with micro focus xas of a tl enriched hydrogenetic ferromanganese crust we show that tl i is oxidised to tl iii during sorption to hexagonal birnessite but not during sorption to todorokite triclinic birnessite and ferrihydrite tl iii forms an inner sphere complex at the hexagonal birnessite surface located at vacant octahedral sites in the phyllomanganate sheets we show that oxidation of tl i to tl iii during reductive dissolution of birnessite is thermodynamically unfavourable and propose that oxidation of tl i is driven by the formation of the tl iii surface complex recent theoretical calculations predict a large equilibrium stable isotope fractionation between tl i and tl iii leading to tl iii species that are enriched in the heavy 205tl isotope in light of this work we propose a molecular sorption oxidation fractionation mechanism that provides a unifying explanation for the recently observed geochemical behaviour of tl in marine ferromanganese rich sediments in this mechanism the proportion of hexagonal birnessite dictates the extent of tl oxidation which controls the extent of tl enrichment and isotope fractionation this work is among the first to provide a molecular explanation for reported trends in trace element enrichments and stable isotope compositions in geologic deposits our molecular sorption oxidation fractionation mechanism will ultimately help interpret tl signals in marine sedimentary archives to provide new constraints on past oceanic and climatic change in addition our mechanism should also help explain compositional relationships of other redox sensitive elements in ferromanganese rich marine sediments that might also be used as paleoceanographic and paleoclimate proxies

estimation of the probability of earthquake occurrence on the basis of logistic models high probability of an earthquake of m 6 5 near the arc junction off northeast japan the probability of the occurrence of an earthquake of m 6 5 is estimated by applying logistic models to seismicity in the hokkaido tohoku region northeast japan it is found that the probability of an earthquake occurrence near the arc junction off northeast japan is high when a specific seismicity pattern appears that is seismic activity increases 7 10 years or decreases 3 6 years before an event of m 6 5 because seismic activity is currently extremely low near the arc junction it is possible that an earthquake of m 6 5 may occur there within a few years specifically the probability estimated on the basis of logistic models is higher than 0 9 for the year of 1988

critical metal enrichment mechanism of deep sea hydrogenetic nodules insights from mineralogy and element mobility abstract the micro nano textural features major and trace element compositions of ferromanganese nodule from the marcus wake seamount group of the western pacific ocean were documented in this study the ferromanganese nodules genetically comprise a core and three types of layers the core is made up of porous quartz and locally fe mn oxides layer close to the core layer i mantle ii and rim iii are featured by a massive dense layer with stromatolite like structure laminated and detrital and dendritic rim respectively these layers contain mainly birnessite goethite and quartz the mn fe ratios 1 0 4 1 mean 1 9 demonstrate a hydrogenetic genesis for these nodules the nodules have moderate enrichments 1000 10 000 ppm of na mg al p k ti co ni and cu with minor enrichments 100 1000 ppm of v zn as sr y zr nb mo ba and pb whereas other elements li sc cr ge se rb sn cs hf w bi th and u have concentrations of several tens of ppm based on the growth rate calculated by co concentration layer i has the lowest mean growth rate 1 8 mm myr followed by layer ii 2 3 mm myr and then layer iii 2 7 mm myr integrating the previous marine nodule studies in the south china sea we suggest that the massive dense layers were possibly resulted from a slow growth rate the conduits of various scales may have promoted the post depositional processes as they enlarged the surface area for fluid dissolution and reprecipitation nickel enrichment is associated with birnessite and promoted by the post depositional processes as evidenced by the higher ni content in the early formed layer i and its decreasing trend from core to rim cobalt may have associated with mn3 and has less effect by post depositional accumulation the fe content which may have related to goethite fe3 o oh shows good correlations with the rey ree y contents this correlation demonstrates the scavenging of reys by hydrothermal fe oxyhydr oxides reys are likely released during the post deposition as the rey contents are decreasing from the core to rim and negatively correlated with the accumulation time the similarity of rey distribution pattern between hydrothermal nodule and goethite bearing and mn oxides free banded iron formation bif may suggest hydrothermal fe may have linked to rey enrichments in deep sea sediments these micro nano sized conduits are well developed in either type i ii or iii layer which likely served as fluid circulating conduits and facilitate post depositional processes