systematics of ti isotopes in carbonaceous chondrite whole rock samples titanium isotopic compositions in whole rock samples are reported for meteorites from all four carbonaceous chondrite classes characteristic isotopic patterns are derived for each class since meteorites in a given class usually though not always give the same pattern no anomalies are resolved at the 47 46 and 48 46 ratios but small 50 excesses are prevalent e 50 46 mean values are ci 1 0 0 8 cm 2 4 0 6 co 3 0 0 5 cv 3 3 0 5 among the three classes where ti anomalies are clearly present the mean values for the 50 excesses are the same within the uncertainties in contrast the ci class gives just a hint of a 50 excess available data including analyses of murchison cm density separates suggest that anomalous ti is not confined to phases in refractory inclusions kakangari a petrologically and chemically peculiar meteorite shows a clear deficit of 50 thereby supporting a previous suggestion that it is a unique carbonaceous chondrite

refractory inclusions in the prototypical cm chondrite mighei abstract refractory inclusions in the mighei cm2 meteorite are very abundant 35 being found in three thin sections of the meteorite the most common are pyroxene rimmed spinel rich inclusions that occur in a range of structural and textural types some inclusions are simple aggregates of crystals or rimmed crystals ranging from loose clusters of spinel grains to distended chains of pyroxene rimmed spinel knots others are more compact and may have experienced recrystallization or melting these include nodular spinel inclusions with polygonal granular textured spinel interiors and pyroxene rims ribbons of spinel in some cases with hibonite and or perovskite that are again rimmed by pyroxene and refractory spherules four inclusions are complex aggregates of several texturally distinct objects each collectively mighei inclusions are similar to those in murchison but appear to be somewhat more altered volatility fractionated and unfractionated trace element patterns similar to those found in refractory inclusions in other carbonaceous chondrites are represented in mighei inclusions and in addition some mighei inclusions have volatility fractionated pattern types not previously found in refractory inclusions in three of the complex aggregates fundamentally different trace element patterns are present within different portions of each inclusion meaning that these objects accreted from genetically different components that never equilibrated with one another subsequent to accretion bulk inclusion magnesium isotopic compositions show minor mass fractionation effects fmg values range from 2 3 to 7 5 but the average fmg value is indistinguishable from normal 1 8 1 2 there are no correlations between magnesium isotopic composition and textural type or trace element pattern type the diverse inclusion types in mighei represent a variety of origins and histories textures suggest that the nodular and banded inclusions may have experienced solid state recrystallization whereas the porous and chain like varieties and complex aggregates have not magnesium isotopic compositions and trace element abundances suggest that the mighei inclusions are unlikely to be evaporation residues and are more likely to be the products of condensation or recondensation processes

quantitative analysis of temporal variations on shoreline change pattern along ganjam district odisha east coast of india this research work describes the shoreline change rate variations of ganjam district of odisha east coast of india for the past 24 years seven shorelines were extracted from multidated satellite images and shoreline change rate has been calculated by using digital shoreline analysis system long term shoreline change rate 1990 2014 of the study area has been calculated using weighted linier regression method short term changes have been computed for different time scales i e 1990 1999 1999 2006 2006 2008 2008 2013 and 2013 2014 using end point rate method the results obtained from the study show that 71 65 of ganjam coast shows accretion pattern and 28 35 of coast falls under erosion category high erosion is mainly noticed in northern side of gopalpur port which is mainly due to recent construction activities short term results reveals that 2006 2008 period shows maximum erosion and 1999 2006 period exhibit maximum accretion in ganjam coast from short term analysis it is observed that shoreline in the study area shows cyclic nature of erosion and accretion pattern the study reveals that tropical cyclones and human activities such as port development construction of breakwaters and groins are the major factors responsible for shoreline erosion in the study area

the proto earth as a significant source of lunar material geochemical evidence continues to challenge giant impact models which predict that the moon formed from both proto earth and impactor material analyses of lunar samples reveal isotopic homogeneity in titanium a highly refractory element suggesting lunar material was derived predominantly from the mantle of the proto earth

processes of selective grain transport and the formation of placers on beaches placers are found on many beaches of the oregon coast in the beach that is the focus of this study the principal placer minerals are ilmenite 22 0 epidote 20 0 garnet 18 7 augite 15 5 hypersthene 8 1 hornblende 5 8 and zircon 2 0 the ilmenite fraction actually being partly chromite a series of beach face sand samples was obtained along a profile when sand was being eroded from the upper beach and transported to offshore bars since the processes of grain selective sorting leading to placer formation were probably most active at such a time the landward most sample contained 96 heavy minerals being part of the placer this concentration systematically decreased offshore to a 6 heavy mineral content in the seaward most sample 54 m offshore determinations of individual heavy mineral concentrations revealed that although they all tended to become concentrated within the placer with light quartz and feldspar dominating the offshore transport the sorting processes were m

a link between oxygen calcium and titanium isotopes in 26 al poor hibonite rich cais from murchison and implications for the heterogeneity of dust reservoirs in the solar nebula placs platy hibonite crystals and related hibonite rich calcium aluminum rich inclusions cais hereafter collectively referred to as plac like cais have the largest nucleosynthetic isotope anomalies of all materials believed to have formed in the solar system most plac like cais have low inferred initial 26al 27al ratios and could have formed prior to injection or widespread distribution of 26al in the solar nebula in this study we report 26al 26mg systematics combined with oxygen calcium and titanium isotopic compositions for a large number of newly separated plac like cais from the murchison cm2 chondrite 32 cais studied for oxygen 26 of these also for 26al 26mg calcium and titanium our results confirm 1 the large range of nucleosynthetic anomalies in 50ti and 48ca our data range from 70 to 170 and 60 to 80 respectively 2 the substantial range of 17o values 28 to 17 with 17o 17o 0 52 18o and 3 general 26al depletion in plac like cais the multielement approach reveals a relationship between 17o and the degree of variability in 50ti and 48ca plac like cais with the highest 17o 17 show large positive and negative 50ti and 48ca anomalies while those with the lowest 17o 28 have small to no anomalies in 50ti and 48ca these observations could suggest a physical link between anomalous 48ca and 50ti carriers and an 16o poor reservoir we suggest that the solar nebula was isotopically heterogeneous shortly after collapse of the protosolar molecular cloud and that the primordial dust reservoir in which anomalous carrier phases were heterogeneously distributed was 16o poor 17o 17 relative to the primordial gaseous co h2o reservoir 17o 35 however other models such as co self shielding in the protoplanetary disk are also considered to explain the link between oxygen and calcium and titanium isotopes in plac like cais

detecting temporal shoreline changes and erosion accretion rates using remote sensing and their associated sediment characteristics along the coast of north sinai egypt the variation during 15 years in the shoreline along the north sinai coast has been determined by analysing tm and etm true colour landsat images from 1986 to 2001 the analyses identified erosion and accretion patterns along the coast the shoreline has advanced west of el bardawil inlet1 el bardawil inlet2 and el arish harbour where the wave induced littoral transport has been halted by jetty construction and beach growth rates are 20 681 69 855 and 20 160 m2 year respectively on the downdrift side of the constructed jetties to the east the shoreline is retreating and beaches erode at rates of 71 710 69 968 and 11 760 m2 year respectively sedimentological analyses of beach sediment samples have indicated selective transport of heavy minerals according to their densities and grain sizes a general correspondence has been found between variation in grain size sorting and heavy mineral content of beach sand and the patterns of shoreline changes

origin and consequences of cyclic ice rafting in the northeast atlantic ocean during the past 130 000 years deep sea sediment cores recovered from the northeast atlantic ocean were examined in order to elucidate the influence of the earth s orbital parameters on major ice rafting analyses of coarse grained ice rafted debris and planktonic foraminifers revealed a strong reaction to the precession signal since 130 000 yr b p dropstone layers have been deposited each half period of a precessional cycle 11 000 1000 yr ice rafting occurs during times of winter minimum summer maximum insolation and summer minimum winter maximum insolation in the first case high summer insolation forces meltwater discharge from the ice sheets into the polar seas which subsequently enhances formation of sea ice during the winter in the second case growth of continental ice enhances iceberg production which also leads to a salinity reduction of surface seawater both situations result in a southward penetration of polar water thus the marine record of dropstones documents ice rafting not only during weichselian stades but also during cold events within interstades the regularity of ice rafting yields a useful framework to calibrate and elucidate climatic changes not only in the region of the north atlantic ocean but also in remote areas such as the pacific ocean and the antarctic

trace element partition coefficients for perovskite and hibonite in meteorite compositions the concentrations of 28 elements were measured using an ion microprobe in perovskite hibonite and coexisting melts in isothermal crystallization experiments on chemical compositions similar to those of compact type a cta ca al rich inclusions cai and to a hibonite glass microspherule the mineral melt partition coefficients d calculated from the measured concentrations for both minerals define reliable d values perovskite and hibonite d s have ranges of 10 2 for si to 20 for th and 3 10 3 for si to 8 for la respectively there are regular relationships between the ionic radius the valence of the trace element and the partition coefficients in perovskite and hibonite while there are differences in the d values between perovskite and hibonite they follow very similar trends with perovskite typically having d values that are 5 10 times higher for the same element perovskite and hibonite d s are almost identical for the divalent cations ba 0 02 and 0 03 respectively and sr 1 1 and 0 8 respectively in our experiments d mg for perovskite is low 0 03 when compared with the value for hibonite 0 5 mineral melt d s for the ree decrease continuously from d la 6 to d lu 0 03 in hibonite for perovskite ree d s increase slightly from d la 10 to d nd 15 and then decrease continuously to d lu 1 0 and d s for trivalent cations with smaller ionic radii than the ree are lower with d al 0 08 and d sc 0 15 lower than d cr 0 8 and d v 1 0 with the exception of d th and d si in perovskite and dsi in hibonite the d values for tetravalent cations and nb the only pentavalent element fall within the range of d s for the ree d th d u equals 3 in perovskite and 15 in hibonite our data can be applied to the genesis and evolution of hibonite in refractory meteorite inclusions for example low ba relative to other refractory elements such as hf zr la etc in hibonite has been observed in some hibonite bearing inclusions since d ba d hf d zr and d la in our experiments low ba may result from the incompatibility of ba in hibonite rather than the increased volatility of ba under oxidizing conditions during condensation in addition since d la d lu 50 for hibonite lree hree ratios of 1 in hibonite in some cta cai from leoville and allende are inconsistent with hibonite equilibrating with the melts that formed these inclusions and the hibonite is relict similar applications are possible with our perovskite partitioning data for example it is likely that high ree 500 1000 chondritic perovskite with th u of 3 4 that are found in the outer region of type b 1 cai have not been in equilibrium with the cai melt that contains 20 ch ree and a th u ratio of 3 and they are probably relics that survived the most recent partial melting event

a petrologic and ion microprobe study of a vigarano type b refractory inclusion evolution by multiple stages of alteration and melting abstract usnm 1623 8 is a type b vigarano inclusion 6 mm in diameter consisting of melilite ak12 72 fassaite 17 23 a12o3 5 17 tio2 anorthite and spinel secondary alteration is negligible and consists of diopside and sparse nepheline melilite is normally zoned and contains up to 0 35 wt na2o higher than generally seen in melilite from other refractory inclusions a strong correlation between akermanite content and na2o in 1623 8 melilite suggests that the na was present during igneous crystallization rather than introduced later by diffusion anorthite in 1623 8 is coarse grained but commonly has an irregular border with neighboring melilite crystals many spinel grains enclosed within anorthite have selvages of melilite around them which in places are continuous with melilite exterior to the anorthite the anorthite appears to be replacing melilite ion microprobe analyses of anorthite in 1623 8 show that there is no detectable excess 26mg in nine anorthite crystals that have 27 al 24 mg as high as 970 implying an upper limit of 26 al 27 al 0 7 one crystal was found that has excess 26mg consistent with 26 al 27 al 0 3 10 6 melilite in the outer portion of the inclusion 27 al 24 mg 2 7 11 5 contains excess 26mg that considered together with spinel and pyroxene defines an isochron consistent with the canonical early solar system value of 26 al 27 al 0 4 5 10 5 melilite near an anorthite 27 al 24 mg 1 6 5 9 has 26mg values in excess of those predicted from 26 al 27 al 0 4 5 10 5 presumably caused by redistribution of radiogenic 26mg from adjacent anorthite the high na2o inferred to have been present in the melt suggests that the precursor solids were na bearing such as for example refractory material having an allende like overprint of feldspathoid bearing secondary alteration the melting event must have been brief in order that not all of the na was vaporized during melting the isotopic composition of the anorthite relative to melilite indicates a subsequent much later after the decay of most or all 26a1 episode of partial melting or solidstate recrystallization that did not affect the al rich melilite but reset most of the anorthite and some mg rich melilite near anorthite because the inclusion is both rimmed and slightly altered this late resetting event appears to have been a nebular one an assumption of homogeneously distributed 26a1 in the regions of the nebula where the inclusion formed and was later modified implies a several millionyear interval between condensation of the precursors and final melting of 1623 8

titanium isotopic anomalies in hibonites from the murchison carbonaceous chondrite abstract the isotopic compositions of titanium in eight grains of hibonite caai 12 o 19 from the carbonaceous chondrite murchison have been determined by high precision secondary ion mass spectrometry using an ion microprobe the titanium in the hibonites varies greatly in 50 ti from about 42 to 8 permil relative to terrestrial with smaller up to 4 permil but clearly resolvable effects in 46 ti and 48 ti these results complement ion probe measurements by fahey et al 1985 of a 100 permil excess of 50 ti in a hibonite grain from the carbonaceous chondrite murray and confirm the presence of widespread negative anomalies suggested by the results of hutcheon et al 1983 on hibonites from murchison the magnitude of these variations seems explicable only in terms of nucleogenic processes which produced extremely variable titanium isotopic abundances in the hibonite source materials the hibonites evidently did not participate to the same extent as most material in the mixing and homogenisation processes that accompanied the formation and later evolution of the solar system thus significant source materials of the hibonites may be the supernova condensates of clayton 1978 and may support the concept of chemical memory clayton 1978 niemeyer and lugmair 1984

ubiquitous isotopic anomalies in ti from normal allende inclusions a newly developed technique for high precision isotopic analyses of titanium was applied to terrestrial rocks and course and fine grained allende inclusions repeated analyses of three terrestrial rocks gave excellent agreement usually less than 2 10 4 deviations with a ti metal standard all seven allende inclusions studied here were previously determined to contain isotopically normal nd and or sm indicating that none belongs to a small group of peculiar inclusions dubbed as fun inclusions yet every inclusion showed a clearly resolvable excess at50ti with e 50 46 deviation from the ti standard in parts in 104 ranging from 7 to 10 for five of the inclusions while two pink fine grained inclusions gave larger excesses of 15 and 28 six inclusions also exhibited greater than 2 deficits at47ti 46ti with an average value greater than 2 e units analyses of pyroxene and melilite separates and bulk samples from one inclusion furnished no evidence for ti isotopic disequilibrium within a single inclusion however the possibility that pyroxene contributed the bulk of the ti in all samples renders this a rather insensitive test a graphical presentation of ti isotopic abundances for these normal allende inclusions two previously analyzed fun inclusions and terrestrial samples demonstrates that at least three distinct components are required the discovery of widespread isotopic anomalies in ti fromnormal allende inclusions establishes ti as the first non noble gas element studied since oxygen to show such isotopic heterogeneity a survey of published nucleosynthetic origins of ti isotopes suggests that the dominant50ti excesses in these inclusions are due to the relative enrichment of isotopes synthesized during hydrostatic burning in or near the core of a massive star such a source is seemingly consistent with the absence of isotopic anomalies in previously analyzed elements and can be tested via its prediction of similar excesses for the neutron rich isotopes of cr fe and ni and their respective radioactive decay products

presolar isotopic and chemical signatures in hibonite bearing refractory inclusions from the murchison carbonaceous chondrite magnesium calcium and titanium isotopic compositions as well as trace element abundances have been determined by ion microprobe mass spectrometry for 37 hibonite bearing inclusions from the murchison carbonaceous chondrite these and previously analyzed hibonite bearing inclusions can be divided into three main groups based on morphological and mineralogical criteria platy crystal fragments placs generally have depletions in the relatively volatile refractory trace elements eu yb mb v ba little or no evidence of 26al i e little or no radiogenic 26mg 26mg and widely variable ca and ti isotopic compositions one plac 13 13 has excess 48ca of 104 and 50ti of 273 the largest effects yet measured in these elements four blue aggregates bags are distinctive in having low overall trace element abundances with large relative depletions in the ultrarefractory elements gd er lu zr hf y sc and mass fractionated mg isotopic compositions enriched in the heavy isotopes large 50ti deficits have been measured in three of the four bags the only bag analyzed for its ca isotopic composition also shows a deficit in 48ca spinel hibonite inclusions shibs show a wide variety of morphologies ranging from bladed hibonite crystals within spinel to spherules of hibonite and spinel to large uniform hibonite crystals within spinel shibs consisting of bladed hibonite in spinel or hibonite spinel spherules typically have ultrarefractory depleted trace element patterns although uncommon ultrarefractory enriched patterns were also found 26mg at a level consistent with 5 10 5 27al and generally small 10 ca and ti isotopic anomalies one of the shib spherules 7 170 has highly unusual systematics with a large 50ti deficit only a small 48ca deficit and no 26mg the large hibonite crystals within spinel have variable trace element patterns commonly with anomalies in the relatively volatile elements ce eu and yb 26mg is present in some of these inclusions but none of this type of shib has large ca or ti isotopic anomalies while at least four distinct components are required to model the ti isotopic compositions three components are sufficient to describe the variations in ca isotopic compositions measured thus far the systematics of plac 13 13 with large excesses of 48ca and 50ti match the predictions of the multiple zone mixing model for nucleosynthesis in supernova ejecta to a maximum neutron excess of 0 159 compositions depleted in 48ca and 50ti are unlikely to represent discrete nucleosynthetic components but represent material with a shortfall of neutron rich material relative to the solar system abundances additional components must be present but are not easily resolved within the morphological groups of hibonite bearing inclusions a few have exceptional chemical and isotopic characteristics such as shib spherule 7 170 however independent of the morphological groups there are correlations in hibonite isotopic systematics and chemistry that hold for all inclusions studied 1 no inclusion has both a large 50ti anomaly and 26mg and 2 inclusions depleted in the ultrarefractory elements have 26mg with the exception of those which have a large 50ti anomaly these features clearly establish a relationship between chemical and isotopic characteristics of the inclusions which must predate their formation several components were combined probably as mixtures of dust grains or crystals and were melted to form refractory inclusions the nucleosynthetic anomalies must be inherited from stellar environments it is possible that the depletions in ultrarefractory elements are also a memory of stellar condensation and are not necessarily related to a condensation event in the solar nebula as has generally been assumed

titanium isotopic anomalies in meteorites high precision analyses of ti are reported for samples from a variety of meteorite classes the expanded data base for allende inclusions still shows ti isotopic anomalies in every inclusion all the coarse grained inclusions give quite similar patterns but fine grained inclusions show more variable and sometimes larger anomalies one inclusion 3675a was analyzed because others identified it as a possible fun inclusion due to its mass fractionated mg this designation is supported by the significantly more complex ti isotopic pattern for 3675a compared to all our other allende inclusions available data fail to suggest that any particular allende mineral phase including a chromite carbon fraction from an acid residue is especially rich in anomalous ti we also find anomalous ti in a bulk sample of a cl chondrite and in matrix separates from c2 chondrites the excesses of 50ti are smaller than for allende inclusions and subtle differences in ti isotopic patterns tentatively suggest that parent materials for c1 c2 matrix and allende inclusions are not directly related analyses of chondrules from unequilibrated ordinary chondrites did not yield clear evidence for anomalous ti but some larger than usual deficits at 5046 give encouragement for future work in this direction comparing the magnitude of isotopic shifts at 50ti and 16o for all these meteorite samples indicates that they are not correlated but the data do not preclude a correlation between concentrations of exotic 50ti and 16o atoms whether or not allende fun inclusions are considered at least 4 distinct isotopic components of ti are required to account for the observed isotopic variations the ti data cannot be plausibly explained in terms of an early solar system particle irradiation instead neutron rich hydrostatic burning within a star is probably responsible for the dominant 50ti anomalies while s process mechanisms are viable sources for some of the more subtle ti variations we suggest that the ti anomalies are linked to a diversity of nucleosynthetic sources and the highly refractory behavior of ti therefore some form of chemical memory from the ism rather than late stage supernova injection is most likely responsible for the preservation of observed isotopic heterogeneities

evidence for mo isotope fractionation in the solar nebula and during planetary differentiation abstract mass dependent mo isotope fractionation has been investigated for a wide range of meteorites including chondrites enstatite ordinary and carbonaceous chondrites iron meteorites and achondrites eucrites angrites and martian meteorites as well as for lunar and terrestrial samples magmatic iron meteorites together with enstatite ordinary and most carbonaceous chondrites define a common 98 95 mo value of 0 16 0 02 relative to the nist srm 3134 mo standard which is interpreted to reflect the mo isotope composition of bulk planetary bodies in the inner solar system heavy mo isotope compositions for iab iron meteorites most likely reflect impact induced evaporative losses of mo from these meteorites carbonaceous chondrites define an inverse correlation between 98 95 mo and metal content and a positive correlation between 98 95 mo and matrix abundance these correlations are mainly defined by cm and ck chondrites and may reflect the heterogeneous distribution of an isotopically light metal and or an isotopically heavy matrix component in the formation region of carbonaceous chondrites alternatively the elevated 98 95 mo of the cm and ck chondrites could result from the loss of volatile isotopically light mo oxides that formed under oxidized conditions typical for the formation of these chondrites the mo isotope compositions of samples derived from the silicate portion of differentiated planetary bodies are heavy compared to the mean composition of chondrites and iron meteorites this difference is qualitatively consistent with experimental evidence for mo isotope fractionation between metal and silicate the common 98 95 mo values of 0 05 0 03 of lunar samples derived from different geochemical reservoirs indicate the absence of significant mo isotope fractionation by silicate differentiation or impact metamorphism volatilization on the moon the most straightforward interpretation of the mo isotope composition of the lunar mantle corresponds to the formation of a lunar core at a metal silicate equilibration temperature of 1800 200 c the investigated martian meteorites angrites and eucrites exhibit more variable mo isotope compositions which for several samples extend to values above the maximum 98 95 mo 0 14 that can be associated with core formation for these samples post core formation processes such as partial melting metamorphism and in the case of meteorite finds terrestrial weathering must have resulted in mo isotope fractionation estimates of the metal silicate equilibration temperatures for mars 2490 770 c and the angrite parent body 1790 230 c are thus more uncertain than that derived for the moon although the mo isotope composition of the bulk silicate earth has not been determined as part of this study a value of 0 16 98 95 mo 0 can be predicted based on the chondrite and iron meteorite data and by assuming a reasonable temperature range for core formation in the earth this estimate is in agreement with four analyzed basalt standards 0 10 0 10 improved application of mass dependent mo isotope fractionation to investigate core formation most of all requires an improved understanding of potential mo isotope fractionation during processes not related to metal silicate differentiation

correlated morphological chemical and isotopic characteristics of hibonites from the murchison carbonaceous chondrite twenty four hibonite dominated refractory grains from the murchison carbonaceous chondrite have been identified from polished grain mounts of density separates and have been morphologically and chemically divided into three groups 1 14 colourless platy crystal fragments placs with less than 2 7 tio2 2 3 pleochroic blue aggregates bags which are composed of crystal plates and fragments and have tio2 concentrations between 5 1 and 6 5 3 six spinel hibonite spherules and crystal aggregates shibs often with spinel fe silicate and clinopyroxene rims the maximum tio2 concentrations of hibonite in the shibs ranges from 3 5 to 7 6 but the tio2 concentration in one grain was heterogeneous and ranged from 0 5 to 5 0 hibonite in all types is stoichiometric with ti and mg predominantly in a coupled substitution of mg2 and ti4 for 2al3 one grain with a rounded hibonite core does not clearly fit into the three designated groups the hibonites have been analysed by ion microprobe mass spectrometry for their mg and ti isotopic compositions twelve of the placs have 26al27al 0 ratios less than 1 10 5 but the other two placs have 26al27al 0 of 5 5 10 5 and 7 7 10 5 the excess 26mg may reflect initial mg isotopic heterogeneities in the source region of the placs or be the result of in situ26al decay in which case the distribution of 26al was heterogeneous three bags show substantial positive mass fractionation of mg one grain has excess 26mg while the other two have 26mg depletions the 26mg depletions indicate the preservation of mg isotopic anomalies in the bags but the excess 26mg in one grain could be due to in situ26al decay the six shibs have excess 26mg that is correlated with 27al24mg the mg isotopic systematics of the shibs are consistent with the in situ decay of 26al with 26al27al 0 of ca 5 10 5 the unclassified hibonite has a clearly resolved deficit in 26mg titanium isotopic anomalies are common in the hibonites measured here the largest anomalies are in 50ti with variations in 50ti48ti ranging from 50 to 16 relative to terrestrial smaller anomalies are present in 49ti and 47ti the ti isotopic compositions are not directly correlated with morphological type but the placs show the largest variations in isotopic composition whereas the shibs are generally close to terrestrial the presence of hibonite populations with distinct morphological chemical and mg isotopic systematics suggests that there were several hibonite formation episodes within the early solar system the hibonites probably formed by the melting of refractory dust aggregates during local transient thermal events

selective entrainment and transport of mixed size and density sands flume experiments simulating the formation of black sand placers a process based model for the selective entrainment of grains from sands of mixed sizes and densities has been tested by measuring threshold stresses for a range of relative grain sizes in a laboratory flume the model was found to yield good predictions for the selective entrainment of different grain size fractions it predicts that a minimum threshold stress exists for intermediate grain sizes of a mixed size sediment while higher threshold stresses are required for the movement of both smaller and coarser size fractions this prediction is in part confirmed by our flume experiments and it also agrees with results of experiments by other investigators we also conducted flume tests with settling equivalent sediment mixtures to examine grain sorting leading to the concentration of heavy minerals the experiments yielded systematic increases in grain sizes and decreasing heavy mineral concentrations in the transport direction sorting patterns which imitate those found in our parallel studies of placers on ocean beaches

patterns of beach sand sorting and shoreline erosion on the nile delta abstract rapid erosion has occurred on the beaches of the nile delta in response to dam construction that has cut off the river sediment supply this erosion is greatest adjacent to the two distributary mouths with shoreline retreat rates up to 60 m per year the eroded sand is carried alongshore away from the river mouths and deposited in areas of shoreline accretion these patterns of shoreline erosion and deposition are reflected in the mineralogy of the beach sands on a delta wide scale high density opaques garnet and zircon are concentrated in the erosion areas to form black sand placers lower density hornblende as well as quartz and feldspars are preferentially transported out of the erosion areas and deposited in the stretches of accreting shoreline a detailed analysis of these sorting patterns has been undertaken with beach samples from abu quir bay at the western end of the delta concentrations of opaques zircon rutile and garnet decrease exponentially with longshore distance from the river mouth while augite and hornblende increase exponentially the coefficients in the exponential equations are found to be a function of mineral density demonstrating the importance of this grain property in mineral sorting leading to the observed compositional variations along the shores of the nile delta

melt solidification and late stage evaporation in the evolution of a fun inclusion from the vigarano c3v chondrite vigarano 1623 5 is a forsterite bearing refractory inclusion in which oxygen magnesium and silicon show large degrees of mass dependent isotopic fractionation the core of 1623 5 consists of forsteritic olivine fassaite melilite ak89 and spinel all of which show isotopic mass fractionation averaging 30 6 amu for magnesium and 10 0 amu for silicon it is enclosed in a mantle consisting of aluminous melilite ak16 60 spinel perovskite and hibonite hibonite and spinel in the mantle are enriched in heavy isotopes of magnesium by 8 15 amu relative to the core 1623 5 originally formed by solidification of a magnesium rich melt the endemic isotopic mass fractionation may have been caused by evaporation of that melt or may reflect an earlier evaporation event affecting the reservoir from which the interior of 1623 5 formed later flash remelting of the outer part of the core and volatilization of sio2 and mgo from the melt so produced caused formation of a mantle that is in isotopic and petrologic disequilibrium with the core

thulium anomalies and rare earth element patterns in meteorites and earth nebular fractionation and the nugget effect this study reports the bulk rare earth element rees la lu compositions of 41 chondrites including 32 falls and 9 finds from carbonaceous ci cm co and cv enstatite eh and el and ordinary h l and ll groups as well as 2 enstatite achondrites aubrite the measurements were done in dynamic mode using multi collector inductively coupled plasma mass spectrometers mc icpms allowing precise quantification of mono isotopic rees pr tb ho and tm the ci chondrite normalized ree patterns lan lun a proxy for fractionation of light vs heavy rees and eu anomalies in ordinary and enstatite chondrites show more scatter in more metamorphosed petrologic types 4 6 than in unequilibrated types 1 3 chondrites this is due to parent body redistribution of the rees in various carrier phases during metamorphism a model is presented that predicts the dispersion of elemental and isotopic ratios due to the nugget effect when the analyzed sample mass is limited and elements are concentrated in minor grains the dispersion in ree patterns of equilibrated ordinary chondrites is reproduced well by this model considering that rees are concentrated in 200 lm size phosphates which have high lan lun ratios and negative eu anomalies terrestrial rocks and samples from ordinary and enstatite chondrites display negative tm anomalies of 4 5 relative to ci chondrites in contrast cm co and cv except allende show no significant tm anomalies allende cv chondrite shows large excess tm 10 these anomalies are similar to those found in group ii refractory inclusions in meteorites but of much smaller magnitude the presence of tm anomalies in meteorites and terrestrial rocks suggests that either i the material in the inner part of the solar system was formed from a gas reservoir that had been depleted in refractory dust and carried positive tm anomalies or ii ci chondrites are enriched in refractory dust and are not representative of solar composition for refractory elements a new reference composition relevant to inner solar system bodies ci is calculated by subtracting 0 15 of group ii refractory inclusions to ci the observed tm anomalies in ordinary and enstatite chondrites and terrestrial rocks relative to carbonaceous chondrites indicate that material akin to carbonaceous chondrites must have represented a small fraction of the constituents of the earth tm anomalies may be correlated with ca isotopic fractionation in bulk planetary materials as they are both controlled by addition or removal of refractory material akin to fine grained group ii refractory inclusions

calcium isotopic ratios and rare earth element abundances in refractory inclusions from the allende cv3 chondrite abstract refractory inclusions in primitive meteorites are the oldest objects formed in the solar system they exhibit large mass dependent isotopic effects in many elements including si mg and ca indicative of their complex origin we report data for both mass dependent and mass independent e ca isotopic effects and rare earth element ree abundances in six refractory inclusions from the allende cv3 meteorite our data reveal large mass dependent ca isotopic effects in these refractory inclusions with 44 40 ca ranging from 5 60 to 0 35 relative to nist srm 915a which are significantly lower than that of the bulk silicate earth 44 40 ca 1 05 0 04 importantly 44 40 ca is correlated with ree patterns refractory inclusions with group ii ree patterns have lighter ca isotope compositions compared to those with group i ree patterns specifically the studied refractory inclusions form negative 44 ca 40 ca tm er and 44 ca 40 ca nd er trends implying segregation of up to 3 of an ultrarefractory evaporation residue from a chondritic reservoir prior to the formation of refractory inclusions this residue would have to be characterized by high 44 ca 40 ca and low tm er and nd er at 2 levels of 0 5 and 1 5 for e 40 44 ca and e 43 44 ca respectively the six refractory inclusions studied show no detectable 40 ca or 43 ca anomalies relative to the terrestrial standards however five out of the six refractory inclusions do show a 48 ca excess of several e units clearly resolvable from the terrestrial standards

heinrich events triggered by ocean forcing and modulated by isostatic adjustment heinrich events episodes of massive iceberg discharge from the laurentide ice sheet into the north atlantic ocean are triggered by the incursion of warm ocean waters destabilizing the calving front heinrich events are the great belching of armadas of icebergs from ice sheets such as the laurentide ice sheet into the north atlantic but despite decades of research and numerous proposals the mechanism that triggers heinrich events remains intensely debated jeremy bassis et al present new modelling evidence showing that heinrich events are produced by a surprisingly simple mechanism the incursion of warm ocean waters destabilizes calving fronts leading to the abrupt release of ice critically the isostatic rebound of the ocean bed elevates the calving tongue cutting off the marine interface and producing the characteristic sharpness of heinrich events during the last glacial period the laurentide ice sheet sporadically discharged huge numbers of icebergs through the hudson strait into the north atlantic ocean leaving behind distinct layers of ice rafted debris in the ocean sediments1 2 3 perplexingly these massive discharge events heinrich events occurred during the cold portion of millennial scale climate oscillations called dansgaard oeschger cycles2 4 this is in contrast to the expectation that ice sheets expand in colder climates and shrink in warmer climates here we use an ice sheet model to show that the magnitude and timing of heinrich events can be explained by the same processes that drive the retreat of modern marine terminating glaciers in our model subsurface ocean warming associated with variations in the overturning circulation increases underwater melt along the calving face triggering rapid margin retreat and increased iceberg discharge on millennial timescales isostatic adjustment causes the bed to uplift isolating the terminus from subsurface warming and allowing the ice sheet to advance again until at its most advanced position it is poised for another heinrich event this mechanism not only explains the timing and magnitude of observed heinrich events but also suggests that ice sheets in contact with warming oceans may be vulnerable to catastrophic collapse even with little atmospheric warming

astrophysics of cai formation as revealed by silicon isotope la mc icpms of an igneous cai silicon isotope ratios of a typical cai from the leoville carbonaceous chondrite obtained in situ by laser ablation mc icpms together with existing 25 mg 24 mg data reveal a detailed picture of the astrophysical setting of cai melting and subsequent heating models for the chemical and isotopic effects of evaporation of the molten cai are used to produce a univariant relationship between ph2 and time during melting the result shows that this cai was molten for a cumulative time of no more than 70 days and probably less than 15 days depending on temperature the object could have been molten for an integrated time of just a few hours if isotope ratio zoning was eliminated after melting by high subsolidus temperatures e g n1300 k for 500 yr in all cases subsolidus heating sufficient to produce diffusion limited isotope fractionation at the margin of the solidified cai is required these stable isotope data point to a two stage history for this igneous cai involving melting for a cumulative timescale of hours to months followed by subsolidus heating for years to hundreds of years the thermobarometric history deduced from combining si and mg isotope ratio data implicates thermal processing in the disk perhaps by passage through shockwaves following melting this study underscores the direct link between the meaning of stable isotope ratio zoning or lack thereof and the inferred astrophysical setting of melting and subsequent processing of cais 2007 elsevier b v all rights reserved

titanium isotopic anomalies in chondrules from carbonaceous chondrites abstract isotopic analyses of ti from chondrules of carbonaceous chondrites reveal that ti anomalies are present anomalies are detected only at 50ti for a suite of eight allende chondrules four give well resolved anomalies which range from a 50ti deficit of two units to a 50ti excess of nine units no clear link is evident between the structure or composition of the chondrules and the ti anomalies however the chondrule with by far the largest ti isotopic anomaly is also al rich yet the absence of a strict correlation between the ca al ti contents and the ti anomalies together with the similarity of the 50ti excess for the one chondrule to that of most ca al rich inclusions cais indicate that the relation between degree of refractory enrichment and the magnitude of ti isotopic anomalies is not a simple one single chondrules from murchison kaidun and kakangari all fail to exhibit a well resolved anomaly although in the latter two the single analysis of each precludes resolving anomalies of less than three units these observations support the view that the ti isotopic diversity in chondrules is an inherited feature from their precursor assemblages of dust models which envision similar precursors for both chondrules and matrix are consistent with the ti isotopic data but at least two distinct solid matter reservoirs are required for the allende chondrules alone which underscores the diversity in the nebular dust these ti anomalies also caution that more than one dust isotopic component may be necessary to account fully for the oxygen isotopic variations in chondrules the ti anomalies in chondrules argue strongly against models which ascribe the ti anomalies in cais to unique features of their evolution instead heterogeneities were more common in the nebular dust

enhanced productivity on the iberian margin during glacial interglacial transitions revealed by barium and diatoms the portuguese margin is at a critical location for studies of the ocean s behaviour during glacial interglacial climatic changes and the rapid accumulation rates of the sediments enable high resolution palaeoclimatic investigation the sedimentary record of the past 350 ka has been investigated in a 35 m long core from 3 5 km water depth on the slope at 40 n by geochemical isotopic and micropalaeontological techniques the caco3 content of this core as a function of time contains significant milankovitch orbital frequencies of 18 8 23 7 38 0 and 100 6 ka but these are driven primarily by dilution by clay flux variations rather than by caco3 productivity variations the largest signals in the productivity indicators corg ba al and diatom abundance are all observed as simultaneous peaks at the oxygen isotope stage boundaries 10 9 and 6 5 with the signal magnitude in the order 10 9 6 5 for all three indicators smaller coincident signals in corg ba al but not diatoms are also observed at the oxygen isotope stage 2 1 boundary other less prominent peaks in the corg and ba al profiles occur elsewhere including heinrich event horizons but these are not always simultaneous and none contain evidence of the dissolution prone diatom microfossils the 10 9 6 5 and 2 1 oxygen isotope stage transitions represent the three most extreme glacial interglacial sea level rises in the past 350 ky possibly in the same sequence of magnitude when sea level rose rapidly by 120 m from glacial low stands to interglacial high stands the productivity signals at these transitions are contained within 5 ka including bioturbation

a chemical and isotopic study of hibonite rich refractory inclusions in primitive meteorites the ion microprobe has been used to determine the concentrations of a number of trace elements including all 14 stable rare earth elements and the isotopic compositions of ca and mg in seven hibonite rich refractory inclusions hibonite in every inclusion analyzed shows the effect of ree partitioning with other solid or liquid phases in which hibonite is enriched in light over heavy ree compared to other coexisting phases this partitioning causes cl chondritenormalized enrichments to drop by factors of 4 to 22 from lanthanum to lutetium fractionations due to gas solid partitioning of ree are sometimes superimposed on the pattern produced by partitioning between condensed phases two inclusions hal and dh h1 show evidence for formation in extremely oxidizing environments and their ca is mass fractionated in favor of the heavy isotopes by 7 and 12 amu respectively two corundum hibonite inclusions show evidence of extremely high temperature gas solid fractionation such that the more volatile light ree are depleted as a group relative to the more refractory heavy ree these inclusions both have ca that is mass fractionated in favor of the light isotopes hibonite preserves the largest nuclear isotope anomalies in ti found to date faheyet al 1985a hintonel al 1987b but there does not seem to be a simple relationship between chemical composition isotopic mass fractionation and the sign and magnitude of nuclear isotopic anomalies in hibonite rich inclusions one possibility for producing a variety of chemical compositions and degrees of mass fractionation while preserving nuclear isotope anomalies is by multiple cycles of condensation and evaporation in a turbulent protoplanetary accretion disk morfill 1983 morfill and r n clayton 1986a b these cycles could also occur in a presolar nebula with large non axisymmetric temperature and pressure distributions boss 1988 nuclear anomalies are most likely to be preserved in hibonite because hibonite is the most refractory major phase to occur commonly in meteorites

implications for sedimentation changes on the iberian margin over the last two glacial interglacial transitions from 230thexcess 0 systematics abstract the portuguese margin is well suited for studies of the contrasts in north atlantic circulation during glacial and interglacial times because of its rapid sediment accumulation rate this paper reports a 230thexcess 0 based study of sediment accumulation over the past 140 ky a period which includes the last two glacial interglacial transitions in two cores at 2 4 and 3 5 km water depth on a slope transect at 40 n although the independently determined mean sediment accumulation fluxes over the past 140 ky are unequivocally high with means of 13 2 and 10 5 g cm 2 ky 1 in the two cores conventional application of the 230thexcess 0 method yields consistently lower fluxes with means of 3 5 and 3 8 g cm 2 ky 1 these 230thexcess 0 estimates are interpreted as representations of the regional depositional flux through time this 230thexcess 0 regional flux is composed of a carbonate flux of

titanium isotopes and rare earth patterns in cais evidence for thermal processing and gas dust decoupling in the protoplanetary disk titanium isotopic compositions mass dependent fractionation and isotopic anomalies were measured in 46 calcium aluminum rich inclusions cais from the allende cv chondrite after internal normalization to 49 ti 47 ti we found that e 50 ti values are somewhat variable among cais and that e 46 ti is highly correlated with e 50 ti with a best fit slope of 0 162 0 030 95 confidence interval the linear correlation between e 46 ti and e 50 ti extends the same correlation seen among bulk solar objects slope 0 184 0 007 this observation provides constraints on dynamic mixing of the solar disk and has implications for the nucleosynthetic origin of titanium isotopes specifically on the possible contributions from various types of supernovae to the solar system titanium isotopic mass fractionation expressed as 49 ti was measured by both sample standard bracketing and double spiking most cais are isotopically unfractionated within a 95 confidence interval of normal but a few are significantly fractionated and the range 49 ti is from 4 to 4 rare earth element patterns were measured in 37 of the cais all cais with significant titanium mass fractionation effects have group ii and related ree patterns implying kinetically controlled volatility fractionation during the formation of these cais

erosion and accretion rates and their associated sediment characters along ras el bar coast northeast nile delta egypt beach profile data covering the coast of ras el bar northeast nile delta collected during the years from 1990 to 2002 combined with landsat images for the area and sedimentological investigation have been used to identify beach and nearshore seafloor sediment changes along the coast of ras el bar two accretion sectors and one of erosion have been recognized the first accretion sector is located west of damietta harbour where the harbour jetties have halted the littoral transport while the second one is behind a system of detached breakwaters protecting ras el bar resort both the two sectors are characterized by growing shoreline with maximum rates 15 and 10 m year respectively also they have maximum nearshore seafloor accretion rates of 18 and 22 cm year respectively the erosion sector is located east of damietta port and has a maximum rate of shoreline retreat 10 m year erosion of its nearshore seafloor is indicated recording a maximum rate of 20 cm year the rate of net sediment volume change in the area indicates shifting of the accretion sector ii westward responding to installation of the new breakwaters unit the two accretion sectors are characterized by dominance of moderately sorted fine sands in their shore area which change seaward into less sorting very fine sands beach sands of the eroded sector are poorly sorted medium grain size the dominant constituents of heavy mineral species in beach and sea bottom sands are the characteristic assemblages of the nile deposits the sands of the eroded zone are relatively enriched in monazite zircon tourmaline garnet and rutile

environmental impacts of el arish power plant on the mediterranean coast of sinai egypt a monitoring program was undertaken to evaluate the adverse impacts of the el arish power plant on the northeastern sinai coast of egypt this program spanned 28 months and includes intensive hydrographic surveying measurements of waves longshore current littoral drift currents behind the breaker zone offshore currents sea level variation and water quality the shoreline dynamics of the region have been substantially disrupted due to the high intensity longshore transport and the interruption of longshore transport by the shore perpendicular intake breakwaters maximum erosion of 5 5 m year has been documented east of the breakwater this erosion has been continuing eastwards threatening the resort centers on the downcoast beaches on the other hand accretion 11 7 m year is recorded along the western side of the breakwater accumulating great volumes of sand which is transported to the east by littoral currents part of this sand enters the intake basin causing sedimentation problems by the easterly and westerly littoral drifts and cross shore currents in other respect an unprotected offshore channel dredged in front of the water discharger east of the intake acts as an effective trap for the predominantly easterly sand drift subsequently interrupting sediments moving from the east accelerating processes of erosion to the east the cooling and wastewater discharging from the discharger to the sea are insignificantly warmer than the upcoast water and not contaminated with chemical wastes the thermal and chemical plume has no significant effect on the quality of the coastal water in the region

deglaciation of the eurasian ice sheet complex the eurasian ice sheet complex eisc was the third largest ice mass during the last glacial maximum with a span of over 4500 km and responsible for around 20 m of eustatic sea level lowering whilst recent terrestrial and marine empirical insights have improved understanding of the chronology pattern and rates of retreat of this vast ice sheet a concerted attempt to model the deglaciation of the eisc honouring these new constraints is conspicuously lacking here we apply a first order thermomechanical ice sheet model validated against a diverse suite of empirical data to investigate the retreat of the eisc after 23 ka bp directly extending the work of patton et al 2016 who modelled the build up to its maximum extent retreat of the ice sheet complex was highly asynchronous reflecting contrasting regional sensitivities to climate forcing oceanic influence and internal dynamics most rapid retreat was experienced across the barents sea sector after 17 8 ka bp when this marine based ice sheet disintegrated at a rate of 670 gigatonnes per year gt a 1 through enhanced calving and interior dynamic thinning driven by oceanic atmospheric warming and exacerbated by eustatic sea level rise from 14 9 to 12 9 ka bp the eisc lost on average 750 gt a 1 peaking at rates 3000 gt a 1 roughly equally partitioned between surface melt and dynamic losses and potentially contributing up to 2 5 m to global sea level rise during meltwater pulse 1a independent glacio isostatic modelling constrained by an extensive inventory of relative sea level change corroborates our ice sheet loading history of the barents sea sector subglacial conditions were predominately temperate during deglaciation with over 6000 subglacial lakes predicted along with an extensive subglacial drainage network moreover the maximum eisc and its isostatic footprint had a profound impact on the proglacial hydrological network forming the fleuve manche mega catchment which had an area of 2 5 106 km2 and drained the present day vistula elbe rhine and thames rivers through the seine estuary during the bolling allerod oscillation after c 14 6 ka bp two major proglacial lakes formed in the baltic and white seas buffering meltwater pulses from eastern fennoscandia through to the younger dryas when these massive proglacial freshwater lakes flooded into the north atlantic ocean deglaciation temporarily abated during the younger dryas stadial at 12 9 ka bp when remnant ice across svalbard franz josef land novaya zemlya fennoscandia and scotland experienced a short lived but dynamic re advance the final stage of deglaciation converged on present day ice cover around the scandes mountains and the barents sea by 8 7 ka bp although the phase lagged isostatic recovery still continues today

origin of compact type a refractory inclusions from cv3 carbonaceous chondrites compact type a cta inclusions are one of the major types of coarse grained refractory inclusions found in carbonaceous chondrites they have not been studied in a systematic fashion leading to some uncertainties and unproven assumptions about their origin to address this situation we studied a total of eight ctas from allende efremovka and axtell by scanning electron microscopic and electron and ion microprobe techniques these inclusions are very melilite rich ranging from 60 vol to nearly monomineralic also present are mg al spinel 5 20 perovskite trace 3 and in some samples ti rich 17 wt tio2tot fassaite trace 20 and rhonite 1 melilite compositions are mostly between ak15 and ak40 chondrite normalized ree abundance patterns for melilite flat at 10 ci with positive eu anomalies and fassaite slight hree enrichment relative to lree and negative eu anomalies are like those for their counterparts in once molten type b inclusions the patterns for rhonite have positive slopes from la through lu and abundances 10 ci for la and 35 60 ci for lu features of ctas that suggest that they were once molten include rounded inclusion shapes positively correlated sc and v abundances in fassaite radially oriented melilite laths at inclusion rims and the distribution of trace elements among the phases fractional crystallization models show that with one exception the ree contents of perovskite and fassaite arose by crystallization of these phases from late residual liquids that would have resulted from prior crystallization of the observed proportions of melilite and spinel from liquids having the bulk compositions of the inclusions one allende cta ts32 however has several features irregular shape reversely zoned melilite fassaite ree contents that are not readily explained by crystallization from a melt this inclusion may have undergone little melting and may be dominated by relict grains

processes reshaping the nile delta promontories of egypt pre and post protection abstract shoreline positions established from beach profile surveys combined with wave data are jointly analyzed as a function of their contribution to coastal processes to investigate the interaction between waves shoreline orientation and coastal structures along the nile delta promontories rosetta burullus and damietta repeated beach profile surveys along the promontory sectors 64 km long in total have been analyzed to determine rates of shoreline changes prior to construction 1971 1990 and after construction of protective structures 1990 2000 the behavior of coastline pre and post construction indicates that coastal erosion fronting protective structures has declined in the case of the seawalls at the tips of the rosetta and damietta promontories or has been partially replaced by sand accumulation in the case of detached breakwaters at baltim east of burullus promontory and at ras el bar west of the damietta promontory as a consequence downdrift erosion has been initiated in local areas adjacent to these structures in the direction of longshore sediment transport the 5 km long seawall protecting the rosetta promontory has stopped the dramatic erosion of this highly eroded area formerly shoreward retreated 88 m year with adverse local erosion at its west and east ends being 3 and 13 m year respectively similarly the 6 km long seawall built on the eastern tip of the damietta promontory still under construction has nearly stopped the severe erosion which was formerly 10 m year the detached breakwaters at both baltim and at ras el bar have accumulated sand at accretion rates of 37 and 14 m year respectively this sand accumulation is associated with downdrift erosion of 25 and 13 m year at baltim and ras el bar respectively results reaffirm that the original erosion accretion patterns along the nile delta promontories have been reshaped due to the massive protective structures built during the last decade this reshaping along the examined promontories is generally controlled by the temporal variability in the intensity and reversibility of wave directions and associated longshore currents coastline orientation and by the existing coastal protection structures

fassaite composition trends during crystallization of allende type b refractory inclusion melts fassaite is a major phase in type b refractory inclusions and its wide compositional variability makes it an excellent recorder of crystallization induced changes in liquid composition traverses across zoned crystals with electron and ion microprobes show that ti v sc zr and hf decrease from core to rim while mg si rees and other trace elements increase fassaite liquid distribution coefficients derived from the compositions of early fassaite and calculated parent liquid compositions are higher than previously reported fassaite ds e g 0 2 0 8 vs 0 08 0 5 for the trivalent rees possibly due to the high ti and al contents of the fassaite we analyzed log log plots of concentrations of elements vs those of sc give linear relationships with slopes of dixl l 1 dscxl l 1 where dixl l is the bulk crystal liquid distribution coefficient for element i from this relationship we derive effective fassaite liquid ds of 2 8 for sc 1 5 for hf 1 1 for zr 0 52 for y 0 34 for ta 0 29 for nb and 0 31 0 48 for trivalent rees the effective ds are applicable to fassaite crystallizing from melts having the compositions and thermal histories of allende type b refractory inclusions and incorporate any equilibrium and kinetic effects that modify ds during the course of crystallization observed fassaite ree contents can be reproduced by a fractional crystallization model in which the effective ds are used ti3 is more compatible in fassaite than ti4 and without equilibration of the residual liquid with an external reducing gas ti3 titot ratios where titot ti3 ti4 should decrease from core to rim in fassaite crystals comparison of profiles of ti3 titot ratios in several crystals with those calculated for fractional crystallization suggests that the trend in one crystal was controlled by fractional crystallization alone but in two others the virtually constant ti3 titot ratios may imply that the liquids in these inclusions were able to maintain equilibrium with the solar nebular gas throughout crystallization attempts to determine the o2 of fassaite crystallization on the basis of ti3 titot ratios must be based on fassaite grains which are not zoned with respect to ti3 titot the range of observed ree abundances in subliquidus fassaite 7 800 cl for la and 30 2000 cl for lu now encompasses those in grains previously identified as relict removing a major reason for their identification as such rounded fassaite grains with fairly sharp mg rich rims and ti rich cores poikilitically enclosed in mantle melilite in ts34 are candidates for relict grains the grains are so scrich that they would require extreme prior crystallization of spinel and melilite which is inconsistent with their very low ree contents e g la at 3 7 cl we suggest that the cores of these grains are relict and were trapped with liquid during formation of the mantle

evidence for massive discharges of icebergs into the north atlantic ocean during the last glacial period sediments in the north atlantic ocean contain a series of layers that are rich in ice rafted debris and unusually poor in foraminifera1 here we present evidence that the most recent six of these heinrich layers deposited between 14 000 and 70 000 years ago record marked decreases in sea surface temperature and salinity decreases in the flux of planktonic foraminifera to the sediments and short lived massive discharges of icebergs originating in eastern canada the path of the icebergs clearly marked by the presence of ice rafted detrital carbonate can be traced for more than 3 000 km a remarkable distance attesting to extreme cooling of surface waters and enormous amounts of drifting ice the cause of these extreme events is puzzling they may reflect repeated rapid advances of the laurentide ice sheet perhaps associated with reductions in air temperatures yet temperature records from greenland ice cores appear to exhibit only a weak corresponding signal moreover the 5 10 000 yr intervals between the events are inconsistent with milankovitch orbital periodicities raising the question of what the ultimate cause of the postulated cooling may have been

responses of ras el bar seafloor characteristics to the protective engineering structures nile delta egypt bathymetry of the seafloor in the area in front of ras el bar coast the characters of the seafloor sediments and the effects of protective structures on seafloor bathymetry were examined seafloor depths in front of ras el bar seawall ranged between 2 and 4 m these depths coupled with wave climate result in waves breaking directly onto the wall and exerting high dynamic pressures on the area at the structure s toe the sandy seafloor in front of the wall has been scoured sea water has undermined the wall causing removal of sediment destabilization of its slope and the whole face of the wall has slipped toe protection in the form of a rocky apron is required to prevent such damage west of the seawall the constructed breakwater system has affected the bathymetry of the seafloor in the area shoaling and submerged spits have been formed in the shadow of each breakwater unit the gaps between the breakwater units have attained deep depths and steep slopes scours and steep slopes adjacent to the head of the breakwater units have been recorded seaward of the breakwater system deeper depths and gentle slopes characterize the seafloor offshore onshore current and sediment movements toward the northeast is inferred from the configuration of the bottom contour lines

impacts of wave energy and littoral currents on shoreline erosion accretion along the south west coast of kanyakumari tamil nadu using dsas and geospatial technology the present study investigates the impact of wave energy and littoral current on shorelines along the south west coast of kanyakumari tamil nadu india the multi temporal landsat tm etm images acquired from 1999 to 2011 were used to demarcate the rate of shoreline shift using gis based digital shoreline analysis system the statistical analysis such as net shoreline movement and end point rate were determined from the multi temporal shoreline layers moreover the wave energy and seasonal littoral current velocity were calculated for each coastal zone using mathematical equations the results reveal that the coastal zones which include kanyakumari kovalam manavalakurichi and thengapattinam coasts consisting of maximum wave energy along with high velocity of littoral current have faced continuous erosion processes the estimated wave energy along these zones ranges from 6 5 to 8 5 kj km2 and the observed current velocity varies from 0 22 to 0 32 m s during south west and north east monsoons the cumulative effect of these coastal processes in the study area leads to severe erosion that is estimated as 300 63 69 92 54 12 and 66 11 m respectively however the coastal zones namely rajakkamangalam ganapathipuram muttam and colachel have experienced sediment deposits due to current movement during the north east monsoon however the trend changes during the south west monsoon as a result of sediment drift through backwash the spatial variation of shoreline and its impact on wave energy and the littoral current have been mapped using the geo spatial technology this study envisages the impact of coastal processes on site specific shorelines hence the study will be effective for sustainable coastal zone management

chemical composition of hal an isotopically unusual allende inclusion thirty seven major minor and trace elements were determined by inaa and rnaa in samples of hibonite black rim and portions of friable rim from an unusual allende inclusion hal the peculiar isotopic mineralogical and textural properties of hal are accompanied by very unusual trace element abundances the most striking feature of the chemistry is the virtual absence of ce from an inclusion otherwise highly enriched in ree compared to cl chondrites hal is also depleted in sr ba u v ru os and ir relative to other refractory elements of the lithophile elements determined which are normally considered to be refractory in a gas of solar composition sr ba ce u and v are the most volatile in oxidizing gases the distribution of ree between hibonite and rims seems to have been established when hibonite and other refractory minerals were removed at slightly different temperatures from a hot oxidizing gas in which they previously coexisted as separate grains on the basis of hal s chemical and isotopic composition possible locations for the chemical and mass dependent isotopic fractionation are in ejecta from the low temperature helium burning zone of a supernova and in the locally oxidizing environment generated by evaporation of interstellar grains of near chondritic chemical composition

new constraints on the relationship between 26al and oxygen calcium and titanium isotopic variation in the early solar system from a multielement isotopic study of spinel hibonite inclusions abstract we report oxygen calcium titanium and 26al 26mg isotope systematics for spinel hibonite inclusions shibs a class of calcium aluminum rich inclusions cai common in cm chondrites in contrast to previous studies our analyses of 33 shibs and four shib related objects obtained with high spatial resolution demonstrate that these cais have a uniform 17o value of approximately 23 similar to many other mineralogically pristine cais from unmetamorphosed chondrites e g cr cv and acfer 094 five shibs studied for calcium and titanium isotopes have no resolvable anomalies beyond 3 uncertainties this suggests that nucleosynthetic anomalies in the refractory elements had been significantly diluted in the environment where shibs with uniform 17o formed we established internal 26al 26mg isochrons for eight shibs and found that seven of these formed with uniformly high levels of 26al a multi cai mineral isochron yields an initial 26al 27al ratio of 4 8 10 5 but one shib has a smaller initial 26al 27al of 2 5 10 5 indicating variation in 26al 27al ratios when shibs formed the uniform calcium titanium and oxygen isotopic characteristics found in shibs with both high and low initial 26al 27al ratios allow for two interpretations 1 if subcanonical initial 26al 27al ratios in shibs are due to early formation as suggested by liu et al 2012 our data would indicate that the cai formation region had achieved a high degree of isotopic homogeneity in oxygen and refractory elements before a homogeneous distribution of 26al was achieved 2 alternatively if subcanonical ratios were the result of 26al 26mg system resetting the clustering of shibs at a 17o value of 23 would imply that a 16o rich gaseous reservoir existed in the nebula until at least 0 7 ma after the formation of the majority of cais