modern and late pleistocene b ca ratios of the benthic foraminifer planulina wuellerstorfi determined with laser ablation icp ms incorporation of boron into foraminiferal shells is thought to be primarily governed by the carbonate chemistry of the ambient seawater suggesting that it can be reconstructed from b ca ratios to this end b ca ratios of the benthic foraminifer planulina wuellerstorfi from south atlantic core top samples have been analyzed using laser ablation inductively coupled plasma mass spectroscopy la icp ms to provide additional information on intratest trace element heterogeneity results show that boron is heterogeneously distributed within and between shells with content variations of approximately 43 displayed within a single shell b ca is higher in the youngest chambers opposite to the observed between chamber variability of mg ca this may be explained by ontogenetic changes of physiological processes that increase the ph of the calcifying fluid and thus the borate concentration while decreasing mg ca to promote calcification despite this heterogeneity mean b ca ratios are positively correlated with the deepwater calcite saturation state co32 in line with previous studies we apply this empirical relationship to reconstruct co32 for the late pleistocene to holocene using samples from a depth transect in the equatorial atlantic reconstructed co32 values confirm previous studies suggesting that caco3 oversaturated north atlantic deep water was reduced during glacial periods whereas caco3 undersaturated antarctic bottom water expanded vertically and propagated northwards in summary our data demonstrate that bulk b ca in p wuellerstorfi reliably reflects variations in co32 despite the strong physiological control of boron incorporation

microdistribution of mg ca sr ca and ba ca ratios in pulleniatina obliquiloculata test by using a nanosims implication for the vital effect mechanism the mg ca ratio within foraminiferal calcareous tests shells is widely used to reconstruct past seawater temperature however recent studies reported that the organic components within a test affect the mg ca distribution in this study we have measured the mg ca sr ca and ba ca ratios within the planktonic foraminifera pulleniatina obliquiloculata by using a nanosims secondary ion mass spectrometer sims which has excellent spatial resolution 1 m and allows us to compare the distribution of chemical compositions with that of the organic components element compositions show banding distributions composed of alternately higher and lower values of those elemental ratios the mg ca ratios previously considered to be mainly controlled by calcification temperature show larger variations than the values expected from the seawater temperature at the habitat depth of p obliquiloculata comparison of the elemental distribution with the test microstructure reveals that the bands of high mg ca and sr ca ratios correspond with layers of the organic components such coincidence suggests that the organic components strongly affect the mg ca and sr ca ratios within a test in spite of the heterogeneous distribution temperature estimated from the averaged mg ca ratio within a test is consistent with seawater temperature at the habitat depth of p obliquiloculata indicating that whole mg ca ratio of foraminiferal test may be useful as paleotemperature proxy in contrast to the mg ca ratio the heterogenity in ba ca ratio which previously has been considered to be mainly controlled by the ambient seawater composition is not fully matched with the layers of the organic compositions although the organic components concentrate ba other unknown factors appear to also cause heterogenity in ba incorporation

trace element variations in coeval holocene speleothems from gb cave southwest england we report trace element mg sr and ba records based on laser ablation inductively coupled plasma mass spectrometry la icp ms from three coeval holocene speleothems from great chamber in gb cave southwest england the trace element records are placed on a common timescale on the basis of a suite of tims 230th 234u ages this permits assessment of the reproducibility of the trace element record in coeval speleothems the trace element records are not coherent raising dobuts over the reliability of individual trace element records as potential archives of palaeoenvironmental information mg sr in speleothem calcite has been proposed as a potential palaeothermometer as mg partitioning into calcite from water is temperaturedependent while sr partitioning into calcite is temperature independent however we present the results of calculations which demonstrate that the observed mg sr values in the three stalagmites cannot have been produced by holocene temperature changes alone and that other processes m

mg ca ratios of the benthic foraminifera oridorsalis umbonatus obtained by laser ablation from core top sediments relationship to bottom water temperature 1 a laser ablation system connected to an inductively coupled plasma mass spectrometer was used to determine mg ca ratios of the benthic foraminifera oridorsalis umbonatus a set of modern core top samples collected along a depth transect on the continental slope off namibia 320 2300 m water depth 2 9 to 10 4 c was used to calibrate the mg ca ratio against bottom water temperature the resulting mg ca bottom water temperature relationship of o umbonatus is described by the exponential equation mg ca 1 528 e0 09 bwt the temperature sensitivity of this equation is similar to previously published calibrations based on cibicidoides species suggesting that the mg ca ratio of o umbonatus is a valuable proxy for thermocline and deep water temperature

characterization of contaminant phases in foraminifera carbonates by electron microprobe mapping the advent of new microanalytical techniques such as electron microprobe mapping emp and laser ablation microsamplers coupled to mass spectrometers la icp ms provides a new array of possibilities to explore in great detail the trace elements distribution in foraminiferal carbonates here we apply these techniques to characterize diagenetic phases present in foraminiferal shells from ocean drilling program site 1240 in the panama basin a region characterized by the presence of manganese rich minerals in the sediments the combined application of these techniques allows us to characterize the elemental and spatial distribution on the surface and across the foraminiferal shells results illustrate the presence of at least two different mn rich contaminant phases in the foraminiferal carbonates mn rich carbonates and ferromanganese oxides elemental maps also highlight the relevance of the foraminifera shell texture and porosity in the distribution and formation of these contaminant phases in the case of neogloboquadrina dutertrei mn phases form a continuous thin layer in the inner part of the chambers whereas for globigerinoides ruber mn phases have a rather patchy distribution and are usually found within the pores significant high magnesium concentrations are always associated with these mn rich phases these new findings support the need of removing these mn rich contaminant phases in order to measure accurately the mg ca ratios in the foraminifera shell and therefore obtain reliable mg ca paleotemperature reconstructions

mg ca variation in planktonic foraminifera tests implications for reconstructing palaeo seawater temperature and habitat migration the nature of compositional variability within the tiny calcitic shells tests that are precipitated by planktonic foraminifera has been investigated using laser ablation inductively coupled plasma mass spectrometry la icp ms systematic large and correlated variation of mg ca mn ca ba ca and zn ca but relatively uniform sr ca are observed through the test walls of analysed species globigerinoides sacculifer globigerinoides ruber neogloboquadrina pachyderma and neogloboquadrina dutertrei distinct chamber and chamber wall layer compositions can be resolved within individual tests and mg ca compositional differences observed in sequentially precipitated test components of the different species analysed are consistent with seawater temperature changes occurring with habitat migration during their adult life cycle stages estimated test calcification temperatures are in keeping with available seawater temperature constraints indicating the potential for accurate seawater temperature reconstruction using la icp ms mg rich 1 6 mol mg surface veneers that are also enriched in mn ba and zn have been found on all species and all fossil tests as well as on live sampled tests of g ruber with the latter suggesting a possible biogenic origin these mg rich surfaces bias bulk test compositions toward higher mg ca values by between 5 and 35

variations in mg ca and sr ca ratios of planktonic foraminifera caused by postdepositional dissolution evidence of shallow mg dependent dissolution a comparative study has been made of two species of planktonic foraminifera g tumida and g sacculifer in a depth transect on the ontong java plateau western equatorial pacific g tumida tests from core top sediments showed decreasing mg ca 2 65 1 25 mmol mol and sr ca 1 50 1 16 mmol mol ratios with increasing water depth 1600 4400 m while no such variation was found in g sacculifer tests in excess of 355 m average mg ca 3 6 mmol mol sr ca 1 4 mmol mol artificial dissolution of g tumida tests led to a decrease in both mg ca and sr ca but in g sacculifer there was no significant change in the ratios analyses by electron microprobe revealed that mg ca of the inner chamber calcite in g tumida tests was much higher than that of the calcite crust keel whereas sr ca was only slightly elevated there were no consistent spatial differences in either mg ca or sr ca for g sacculifer tests dissolution in the oceans gives rise to the removal of the chamber calcite in g tumida about 30 of the total calcite leaving the keel calcite although g tumida is thought of as a dissolution resistant form the majority of mg ca and sr ca depletion and chamber loss occurs above the lysocline it is also possible that much of the mg enriched gametogenic calcite has been lost by dissolution from g sacculifer above 1600 m mg content has a significant effect on the dissolution susceptibility of planktonic foraminifera calculations show that the saturation horizon for mg rich parts of tests may be elevated by several hundred meters compared with normal calcite

the potential of ion microprobe analysis in detecting geochemical variations across individual foraminifera tests 1 trace element chemistry variations within individual foraminifera tests may provide valuable information on past ocean conditions however the combination of thin test walls and the presence of surface contaminants not held within the carbonate structure provide a stringent test to microanalytical methods we analysed two tests of the benthic foraminifera ammonia batavus by ion microprobe and compared two sets of analytical conditions using apertures to restrict the size of the analysed area to ca 10 m diameter reduced the effects of sample contamination sr concentrations were unaffected by any contamination encountered and mg could be determined provided checks were made for silicate contamination using al si and k intensities measured sr concentrations 1 012 1 379 mmol mol 1 were in reasonable agreement with previously reported values mg concentrations 0 691 1 412 mmol mol 1 were significantly lower than values reported previously for calcitic benthic species significant variations in sr concentrations occurred within individual test chambers and may reflect the juxtapositioning of calcite of different ages as the test is deposited significant variations in mg and sr concentrations also occurred between test chambers

cadmium zinc copper and barium in foraminifera tests the concentrations of cadmium zinc copper and barium have been determined on 2 mg samples of single species foraminifera populations cleaning techniques were tested using north atlantic core tops and followed by a detailed downcore study for the last 30 000 years in south atlantic core v22 174 raw foram tests cleaned by crushing followed by ultrasonic removal of fine grained material and dissolved in a ph 5 5 acetate buffer contain appreciable amounts of trace elements associated with ferromanganese and alumino silicate contaminants a reductive complexing cleaning treatment reduces ferromanganese contamination by 1 2 orders of magnitude acetate buffers at ph 5 5 complex iron and raise the solubility of ferromanganese oxides these buffers are unsuitable for separating carbonate lattice bound trace elements from the fraction associated with ferromanganese phases improved mechanical and ultrasonic reductive cleaning combined with a mild dissolution in distilled water under 1 atm pco2 reduces contaminant levels another order of magnitude the cd and zn concentrations order 10 8 mole cd mole ca and 10 5 mole zn mole ca of species with low surface area show an increase with decreasing isotopic temperatures this increase is consistent with the increasing concentrations of these metals from low values in surface waters to higher values at depth the variance of cd and zn over the last 30 000 years in the central south atlantic is consistent with the probable variability of the dissolved trace elements at the calcification levels of the species analyzed cu and ba are irreproducible and probably sensitive to residual contaminant phases the trace element content of the tests differs from levels observed in a recent coprecipitation study foraminifera may be a significant vector in zinc cycling in the ocean

porites corals as recorders of mining and environmental impacts misima island papua new guinea abstract in 1989 open cut gold mining commenced on misima island in papua new guinea png open cut mining by its nature causes a significant increase in sedimentation via the exposure of soils to the erosive forces of rain and runoff this increased sedimentation affected the nearby fringing coral reef to varying degrees ranging from coral mortality smothering to relatively minor short term impacts the sediment associated with the mining operation consists of weathered quartz feldspar greenstone and schist these rocks have distinct chemical characteristics rare earth element patterns and high abundances of manganese zinc and lead and are entering the near shore environment in considerably higher than normal concentrations using laser ablation inductively coupled plasma mass spectrometry la icp ms we analyzed eight colonies two from high sedimentation two transitional two minor and two unaffected control sites for y la ce mn zn and pb all sites show low steady background levels prior to the commencement of mining in 1988 subsequently all sites apart from the control show dramatic increases of y la and ce associated with the increased sedimentation as well as rapid decreases following the cessation of mining the elements zn and pb exhibit a different behavior increasing in concentration after 1989 when ore processing began and one year after initial mining operations elevated levels of zn and pb in corals has continued well after the cessation of mining indicating ongoing transport into the reef of these metals via sulfate rich waters rare earth element ree abundance patterns measured in two corals show significant differences compared to coral sea seawater the corals display enrichments in the light and middle rees while the heavy rees are depleted relative to the seawater pattern this suggests that the nearshore seawater ree pattern is dominated by island sedimentation trace element abundances of misima island corals clearly record the dramatic changes in the environmental conditions at this site and provide a basis for identifying anthropogenic influences on corals reefs

timing and mechanism for intratest mg ca variability in a living planktic foraminifer abstract geochemical observations indicate that planktic foraminifer test mg ca is heterogeneous in many species thereby challenging its use as a paleotemperature proxy for paleoceanographic reconstructions we present mg ca and ba ca data collected by laser ablation icp ms from the shells of orbulina universa cultured in controlled laboratory experiments test calcite was labeled with ba spiked seawater for 12 h day or night calcification periods to quantify the timing of intratest mg banding across multiple diurnal cycles results demonstrate that high mg bands are precipitated during the night whereas low mg bands are precipitated during the day data obtained from specimens growing at 20 c and 25 c show that mg ca ratios in both high and low mg bands increase with temperature and average test mg ca ratios are in excellent agreement with previously published empirical calibrations based on bulk solution icp ms analyses in general mg band concentrations decrease with increasing ph and or co2 3 but this effect decreases as experimental temperatures increase from 20 c to 25 c we suggest that mitochondrial uptake of mg2 from the thin calcifying fluid beneath streaming rhizopodial filaments may provide the primary locus for mg2 removal during test calcification and that diurnal variations in either mitochondrial density or activity produce mg banding these results demonstrate that mg banding is an inherent component of test biomineralization in o universa and show that the mg ca paleothermometer remains a fundamental tool for reconstructing past ocean temperatures from fossil foraminifers

determination of intratest variability of trace elements in foraminifera by laser ablation inductively coupled plasma mass spectrometry 1 we have developed a technique to determine the variability of trace elements including li b na mg mn cu zn sr and ba within foraminifera tests using laser ablation inductively coupled plasma mass spectrometry la icp ms this technique has a high spatial resolution width 40 80 m depth 0 5 m is reproducible 8 external reproducibility and has low detection limits generally 0 05 g g 1 we demonstrate that normalization of data to a calcite standard usually gives results that are more consistent with solution icp ms data than normalization to nist 612 rastering into the wall of the final chamber of globigerinoides sacculifer shows that the outermost 1 5 m of the test is enriched in trace elements including mn relative to the interior indicating the presence of a contaminant surface phase pustule calcite close to the aperture of globorotalia tumida has different sr ca and ba ca compared to other parts of the test sr ca and ba ca partition coefficients suggest that the pustule calcite is diagenetic and or formed in a more open system multiple analyses of orbulina universa tests recovered from a latitudinal transect in the north atlantic give a relationship between mg ca and sea surface temperature similar to that reported elsewhere in the literature these initial data demonstrate the validity of this technique and show that it is potentially an extremely powerful microanalytical tool for palaeoceanographic and palaeontological studies

last glacial maximum paleochemistry and deepwater circulation in the southern ocean evidence from foraminiferal cadmium south atlantic benthic foraminiferal cd ca shows no glacial interglacial variation suggesting that the glacial contribution of north atlantic deep water to the southern ocean was not much different than at present in contrast cd ca in southeast indian ridge cores show lower glacial bottom water cd comparable to levels in intermediate depths of the north atlantic and significantly lower than in the deep south atlantic low glacial cd ca was also recorded in planktonic foraminifera suggesting a substantial decrease in the nutrient concentration of subantarctic surface water during the glacial maximum which most likely was caused by increased biological productivity the cd data are inconsistent with low glacial benthic foraminiferal 13c which suggest higher nutrient concentration we propose that the low cd ca in the southeast indian ridge records reflects a local source of nutrient depleted deepwater formed during the last glacial maximum by open ocean convection near the antarctic polar front downstream of the kerguelene plateau if this source was limited to the southeast indian basin then its impact on the overall chemistry of glacial circumpolar deepwater was rather small however if during glaciations open ocean convection became the dominant mode of bottom water formation it might have had a greater impact on cpdw chemistry

origin and deformation of high porosity bands in the takanoobane rhyolite lava of aso volcano japan abstract in rhyolite lavas the high porosity bands are often developed they potentially act as pathways for gas movement to the lava surface since explosive activities of lavas are generally considered to be controlled by degassing system understanding the origin and deformation process of the high porosity bands is important to assessing volcanic hazards the takanoobane rhyolite lava in the middle of kyushu island in sw japan is effused at 51 5 ka the volume flow length and thickness are 0 14 km 3 2 km and about 90 m respectively the central crystalline part of the lava is characterized by the light colored bands defined by the high porosity zone hpz on the basis of geological and petrographical studies we revealed that the hpz was primary formed by ductile brittle tearing of the lava known as cavitation according to the ams results the hpzs were subsequently stretched and flattened laterally during the concentric spreading of the lava this deformation process could stretch the hpz not only radially but also laterally this effective stretching developed the hpz into pervasive thin bands since the hpzs act as degassing pathways to the lava surface the pervasive hpz bands may play a role in providing volcanic gasses to void spaces created in surface fold hinges of rhyolite lavas thus this degassing system may promote explosive activity of the lava surface

micromapping of mg ca values in cultured specimens of the high magnesium benthic foraminifera 1 this study measured mg ca values in cross sections of the benthic foraminifer planoglabratella opercularis d orbigny using an electron probe microanalyzer epma spot size 2 m 1000 analyses we cultured clonal juveniles of this species under controlled temperatures this species precipitates high magnesium calcite as its test material mean mg ca values increased linearly with the culture temperature therefore mg ca values in walls of subsequently formed chambers reflected changes in temperature during the experiment foraminiferal specimens yielded variable mg ca values within their test walls which resulted from the pattern of chamber formation and from minor variations of mg ca within one chamber wall

integrated methodology for determining provenance of detrital quartz using optical petrographic microscopy and cathodoluminescence cl properties abstract the provenance of detrital quartz is a useful predictor in frontier basin sandstone reservoirs of the availability of coarse grained quartz grains of plutonic or high grade metamorphic origin the standard approach is to use scanning electron microscope sem panchromatic cathodoluminescence cl imagery and observations from an optical petrographic microscope we describe a work flow modified from previous literature proposals to determine quartz provenance in detrital grains using optical petrographic microscopy and cl properties from both a hot cathode cathodoluminescence microscope attachment hcma and panchromatic sem cl hcma analysis permits better discrimination of different types of metamorphic quartz this method is applied to a middle jurassic to lower cretaceous section in the bandol 1 wildcat well located in the laurentian sub basin south of newfoundland two types of high grade metamorphic quartz are distinguished one with low luminescence as described in previous literature and one with medium blue cl colour and a moderate colour shift that is also known from granulite in the hinterland three phases of detrital supply are identified suggesting progressive unroofing of higher grade metamorphic sources through the middle jurassic and major input of plutonic quartz in the early cretaceous

li sr mg and na in foraminiferal calcite shells from laboratory culture sediment traps and sediment cores abstract constant temperature laboratory culture experiments of the planktonic foraminiferal species globigerinoides sacculifer brady suggest that the ratios of li and sr to ca in the shells are a function of these ratios in the culture solutions mg ca and na ca in the shells did not vary with changes of these ratios in the culture solution these are the first direct determinations of the relationship between foraminiferal shell chemistry and solution composition the possibility of temperature dependence for the minor elemental composition of foraminiferal shells was also investigated in the laboratory and by analysis of several planktonic and one benthic foraminiferal species from sediment trap and sediment core samples the sr ca mg ca and na ca ratios in the natural samples roughly correlate with calcification temperature whereas differences in the li ca ratios are small and not systematically related to temperature however laboratory culture experiments at 20 c and 30 c showed no variation in the li ca sr ca mg ca and na ca ratios with calcification temperature for the planktonic foraminifera g sacculifer and orbulina universa therefore observed differences in the sr ca mg ca and na ca ratios for the sediment trap and core foraminiferal samples cannot be ascribed to direct effects of calcification temperature but may be due to some other environmental factor which is correlated with temperature

biogeochemical controls on palaeoceanographic environmental proxies a review scientific observations of our oceans and climate go back no more than a couple of hundred years most of our information about the evolution of earth s ocean climate system relies instead on proxies primarily measurements of sediment components that respond to changes in environmental parameters this paper provides an overview of some of the most important biological and geochemical proxies and outlines their contribution to our understanding of the ocean climate system we also discuss some of the challenges that need to be overcome to obtain accurate records these include better understanding of the controls on the mechanisms of biomineralization the impacts of post depositional dissolution and diagenesis on primary proxy relationships proxy validation and analytical considerations

corals at their latitudinal limits laser ablation trace element systematics in porites from shirigai bay japan the rapid analytical technique of laser ablation inductively coupled plasma mass spectrometry la icp ms was used to measure the trace elements b mg sr ba and u in a high latitude coral colony porites lobata taken from shirigai bay japan 32 n a wide range of sea surface temperatures ssts 14 5 28 c and upwelling events influenced this coral cold winter ssts caused a decrease and or cessation of skeletal extension measurements of u ca and sr ca indicate an approximately linear response to ssts above 18 c and a non linear response below 18 c mg ca and b ca measurements both showed annual cycles broadly consistent with sst variations but also exhibited intra annual fluctuations not associated with temperature suggesting that the incorporation of mg and b into the coral skeleton was not simply regulated by temperature it is shown that ba ca ratios provide a proxy for wind induced seasonal upwelling this is inferred from the strong correlations between the strength of zonal winds 1 month prior to the sst minimum and the ba ca maximum secondary upwelling events occurred during the summers of 1982 1987 1991 and 1992 these summers were cooler than average and were associated with el nino southern oscillation events

a biomineralization model for the incorporation of trace elements into foraminiferal calcium carbonate measurements of srca of benthic foraminifera show a linear decrease with water depth which is superimposed upon significant variability identified by analyses of individual foraminifera new data for cdca support previous work in defining a contrast between waters shallower and deeper than 2500 m measured element partition coefficients in foraminiferal calcium carbonate relative to sea water d have been described by means of a one box model in which elements are extracted by rayleigh distillation from a biomineralization reservoir that serves for calcification with a constant fractionation factor such that d 1 f 1 f where f is the proportion of ca remaining after precipitation a modification to the model recognises differences in element speciation the model is consistent with differences between dsr dba and dcd in benthic but not planktonic foraminifera depth variations in d for sr and ba are consistent with the model as are differences in depth variation of dcd in calcitic and aragonitic benthic foraminifera the shallower depth variations may reflect increasing calcification rates with increasing water depth to an optimum of about 2500 m observations of unusually lower dcd for some deep waters not accompanied by similar dsr or dba may be because of dissolution or a calcification response to a lower carbonate saturation state