Questions related to Isotope Geochemistry
I'm looking for a laboratory that measures clumped isotopes - Δ47. My research interests are carbonate minerals occurring in ultramafic rocks. I plan to reconstruct the formation conditions of various carbonates from ultramafic massifs from the north-east part of the Bohemian Massif. The carbonates were probably formed in both supergene and hydrothermal conditions and I aim to distinguish how these conditions had changed in terms of time and space. I would like to reconstruct magnesite precipitation conditions using clumped Isotope palaeothermometry.
Please let me know if you are open to collaboration and what are possible costs involved. Long-time scientific cooperation is possible :)
Contact me on Researchgate or email@example.com
I am looking to find out the optimum point of some factor in regard to the geochemical study of ophiolitic rocks, especially pillow basalts, to detect whether it is an E-, N-MORB, or IOB basalt, including:
- The optimum number of samples for a reliable test
- The distance between sampling locations and samples in each location
Generally, I am looking for a standard method for studying the origin of an ophiolite, even if the isotop geochemistry is required. It would be appreciated if expertise can help me with this question.
Mass balance calculations require that carbonates with δ13-C < -5 (per mil) contain some carbon derived from the oxidation of organic matter. Given that several negative isotopic anomalies much smaller than that (< -10) are recorded, notably in the Neoproterozoic, is it possible that there is another source for depletion in 13C?
I hope you are doing well.
Could you please help me calculate the fluid oxygen isotope range also source temperature based on the analyzed magnetite's oxygen isotopic data?
Is there any excel file for automatic calculation?
Greetings, I was willing to reconstruct paleo-temperature of Last Glacial Maximum (LGM) from the oxygen isotope ( δ18O) or Mg/Ca ratio. Therefore. I obtained data from the Pangaea site and arranged them in 3 columns depth, time (Kyrs BP), parameters. The δ18O data were calculated based on G.ruber and benthic, planktonic foraminifera. While the Mg/Ca ratio was extracted from H. elegans.
Now, I am wondering whether I could use any equation(s) that would take the previously mentioned parameters into variables and reconstruct paleo-temperature. I studied some literature where I found the following equation published by McCrea (1950), which was subsequently revised by Epstein et al. (1953):
T(°C) = 16.5− 4.3(δ18Occ − δ18Osw) + 0.14(δ18Occ−δ18Osw)
where δ18Occ is the measured value in calcium carbonate and δ18Osw is the isotope ratio of the water from which it is precipitated. The slope of this relationship means that a 0.23‰ increase in δ18Occ corresponds to a difference of about 1°C (Paul N. Pearson, 2012). I understand that I would put the Isotope ratio's column in the δ18Occ variable, but what should I do about the δ18Osw variable ? As I am planning to derive the paleo-temperature of the LGM, I was wondering that if there's any standard δ18Osw value of that time or do I need separate dataset for that too?
Regarding the ratio of the water, there was something such as conversion of VSMOW/SMOW to VPDB/PDB scale, I would be grateful if someone clarified these with their expertise. Although I do believe my data is already converted to PDB when I downloaded from Pangaea. It also needs to be mentioned that these dataset are from cores in Bay of Bengal. Finally, I welcome any suggestion, advice or tips to reconstruct temperature from the data I gathered. If my approach is wrong, it would be a great help to me if you could me point me out to the right directions or the right equations. I am attaching some screenshot here as well. Thanks in advance.
I am looking for a book
"Radiocarbon dating practices at ANU" by Gupta and Polach, published in 1985.
Can anyone please provide the link or source from where I can get this book?
Dear colleagues, do you know works that study the fractionation of Nd isotopes in magmatic (and metasomatic) processes? There are many works on fractionation of isotopes of Fe, Si, Mg (e.g. (Goel et al., 2012; Huang et al., 2009; Lacks et al., 2012; Wu et al., 2018; Zhu et al., 2015)), calcium (e.g.(Wang (王阳) et al., 2019)), strontium (Morse, 1983) etc in silicate melts. It is geochemical and experimental works, as well as mathematical modelling. But I can’t find publications on fractionation of neodymium isotopes in magmatic processes, one of the most important elements for isotopic geochemistry. Please help me.
Goel, G., Zhang, L., Lacks, D.J., Van Orman, J.A., 2012. Isotope fractionation by diffusion in silicate melts: Insights from molecular dynamics simulations. Geochim. Cosmochim. Acta 93, 205–213. doi:10.1016/j.gca.2012.07.008
Huang, F., Lundstrom, C.C., Glessner, J., Ianno, A., Boudreau, A., Li, J., Ferré, E.C., Marshak, S., DeFrates, J., 2009. Chemical and isotopic fractionation of wet andesite in a temperature gradient: Experiments and models suggesting a new mechanism of magma differentiation. Geochim. Cosmochim. Acta 73, 729–749. doi:10.1016/j.gca.2008.11.012
Lacks, D.J., Goel, G., Bopp, C.J., Van Orman, J.A., Lesher, C.E., Lundstrom, C.C., 2012. Isotope Fractionation by Thermal Diffusion in Silicate Melts. Phys. Rev. Lett. 108, 065901. doi:10.1103/PhysRevLett.108.065901
Morse, S.A., 1983. Strontium Isotope Fractionation in the Kiglapait Intrusion. Science (80-. ). 220, 193–195. doi:10.1126/science.220.4593.193
Wang (王阳), Y., He, Y., Wu, H., Zhu, C., Huang, S., Huang, J., 2019. Calcium isotope fractionation during crustal melting and magma differentiation: Granitoid and mineral-pair perspectives. Geochim. Cosmochim. Acta 259, 37–52. doi:10.1016/j.gca.2019.05.030
Wu, H., He, Y., Teng, F.-Z., Ke, S., Hou, Z., Li, S., 2018. Diffusion-driven magnesium and iron isotope fractionation at a gabbro-granite boundary. Geochim. Cosmochim. Acta 222, 671–684. doi:10.1016/j.gca.2017.11.010
Zhu, D., Bao, H., Liu, Y., 2015. Non-traditional stable isotope behaviors in immiscible silica-melts in a mafic magma chamber. Sci. Rep. 5, 17561. doi:10.1038/srep17561
If we assume that in the water (porewater) the 222Rn is coming only from the 226Ra in the sediment, how is the relation that can I use to calculate the quantity of 222Rn in water coming from the 226Ra in sediments?
I am sure that I can not simply assume that all the 226Ra in the measured sediments will become 222Rn in porewater, but I think there are many factors influencing the relation between them (maybe the salinity ? recoil effect?? )
Can you suggest me some papers or arguments for understand which formula use and which are the influencing parameters of this process?
In order to estimate the sources of particulate organic matter in a large freshwater lake. I measure the C/N ratio and C13 and also the n-alkanes as the biomarker to eluciate the potential sources of POM.
However, the results is very confusing. Because most of the POM have appraent peaks at c27 or c29 of alkanes profile (terrestrial signal), which have low C/N ratio as 3 to 5 (phytoplankton signal). I can understand that sometimes the clay particles from terrestial soil will have lower C/N, which are already reported by many references.
But these particles are also have low POC/chla ratio (<100), and a very good linear relationship of POC and chla was observed(R2>0.8).
Can anyone give some clue or suggestion? Thanks a lot.
Solubility of apatite is highly addressed in mineralogical and material studies.
Heating is one of the major processes in apatite industry. In this study, synthesized
hydroxylapatite (HAp), geological fluorapatite (FAp), and bone bioapatite (BAp) were heated
at various temperature (100-900 oC) for analyses. The mineralogy and solubility of the three
apatites were analyzed by XRD, ATR-IR, and ICP. Release of Ca and P in water for BAp
reach the maximum when heated at 200 oC, i.e., 0.215 mmol/L for Ca and 0.106 mmol/L for
P. The value is higher than the maximum values (heated at 900 oC) of solubility for HAp and
FAp. The heating temperature at 600 oC is a re-crystallization point for all the three types of
apatites. Especially, the crystallinity of BAp is significantly elevated at >600 oC. Phase of
geological FAp is relatively stable during heating up to 900 oC. Phase of =-TCP is present
when heating HAp at 800 to 900 oC. In addition, BAp is transformed to the resemblance of
HAp. However, no =-TCP was detected for BAp during heating between 800 to 900 oC,
which is probably due to its Ca-deficiency.
materials and fertilizer.
I am trying to understand the diet of different fish parasites using stable isotope analysis. I have indications (isospace) that some of them are feeding directly on the fish tissues, but others on other sources (not fish tissues). How do I correct C13 and N15 for fractionation in this case? Are you aware of studies and /or correction factors applied to fish parasites?
Student is trying to explain the origin and petrogenesis of basic and intermediate igneous rocks.
I study the REE geochemistry of coal samples. Different REE-distribution patterns is drawn when the different background value is selected. There is a negative Ce anomaly when I use chondrite, but it becomes positive when I use the others. I have the same problem with Eu. I don't know that the samples should be interpreted as having positive Ce anomaly (using NASC, UCC, PAAS) or negative Ce anomaly (based on chond. normalized values). Generally the total REE content of the samples are low, ranging from 8 to 50 ppm (below the all background values).
At this time I am looking for a person or institute which or that can help in the analytical part of strontium isotope geochemistry on fossil shells in order to implications for chronostratigraphic and palaeoenvironmental interpretations.
I would be grateful if you send me any REF on estimation of total CO2 release from Emeishan large igneous province. Besides (Ganino and Arndt, 2009)!
Can anyone suggest or help with materials that could be of help in understanding 'sulphur isotope geochemistry in oil reservoir fluids'?
We want to use scales of fish to follow the variations of Delta O18 . However, these fish are archived in Formol/Formaldehyde during some years and so we have a question " What is the effect of preservative as Formol/Formaldehyde on the analysis of Delta O18 ?"
We have used U-Pb zircon dating for some young magmatic rocks (<100 Ma), through ablation and mass spectrometery (LA-ICPMS) method. Discordancy (i.e., (1-(206Pb/238U age ÷ 207Pb/235U age)) for about 1/3 of the zircons (100 of 280) is higher than 30%, and reaches up to 60%.
If we use Tera-Wasserburg diagram to plot the data, without common lead correction, are the results reliable?
Can anyone be kind enough to recommend few article about continental oxygen fugacity? i want to learn about the oxygen fugacity of the magma derived from the continental crust.
The name of the formation is Islay (Lossit) Formation in Scotland. The age is Precambrian (probably Cryogenian).
Lithology: The mottled (light grey) is limestone, and the upper darker grey bed is dolostone.
I am guessing a microbial structure (Thrombolite).
Sm/Nd isotopes are normally determined as whole-rock compositions, for studying the source and model ages of granites, but I rarely see Lu/Hf whole-rock compositions in papers. I will have these data and maybe some zircon Hf isotopic analyses as well. I would like to know the pros and cons of Hf whole-rock isotopes and Zircon Hf isotopes for studying the source of granitoids.
Am working on the birimian Basin granitoids in Ghana. Petrographic observations, major, trace element and ree geochemistry show that the granitoids rocks have been derived from crustal anatexis of the host proterozoic metasedimentary biotite schist but isotopic values reported by other authors show that the rocks are from a juvenile mantle source. However am I of the view that it is the due to the primitive nature of the proterozoic sediments that is given isotopic signatures of a possible mantle source. As such how would like to know how to prove the primitive nature of the host metasedimentary biotite schist in support of my argument using the trace elements and ree.
K2O contents of our rhyolites are high (about 4%). However, there are not K-feldspar in our samples. The main crystal phase in the rhyolites is Na-rich plagioclase. Why? What controls the crystallization behavior of K-feldspar? Are there any papers about that?
This Field photo shows the alternating layers of Fuchsite Quartz and Barite formed during Archean period, in Dharwar craton. Any suggestion about the interpretation?
With Regards, Sagar
In some cases, correlation between the Chemical Index of Weathering (CIW) and the major elements is used to evaluate the element mobility affected from the alteration. I am wondering whether this index could be also applied to the granitic gneisses that have expericenced deformation and metamorphism. Or do you have any useful information for evaluating the element mobility resulted from the deformation and metamorphism.
Maybe it's too simple for you, but I have been recently bothered by one problem. If only X, Y, and their standard error (SE) are known, how to calculate the SE of (X+Y), (X*Y), and (X/Y)?
Thank you in advance!
Uraninite grains usually contain U+4 in the structure; but with time, auto-oxidation of the U+4 to U+6 occurs due to alpha radiation. Is there a method to quantify the different amount?
Carbon dating question: Can traditional radio carbon techniques be used to date mammal skeletal samples in the 500-200 years BP range? We occasionally recover bison skeletal remains from a wetland area on the National Elk Refuge (NER)in Jackson Hole, Wyoming. Bison were extirpated from NER from approximately 1840-1975, and these remains clearly pre-date 1975. I would like to establish the age of these specimens. Any help would be appreciated.
We know the formula for Sm-Nd isochronic age is (143Sm/144Nd)i=(143Sm/144Nd)0+(147Sm/144Nd)i*（e^λt-1). Here, why we use 144Nd rather than 145Nd or 146Nd as denominator, since 144Sm has isobaric inference on 144Nd.
When we did the Ru analysis with ID-MC-ICP-MS using 99Ru as a spike and by measuring the 101Ru/99Ru ratio to determine the Ru concentration in the samples, sometimes a strong signal on mass 101 can be found. For example, when we analyze the PGE reference material WPR-1, sometimes we can find strong signal on mass 101 during MC-ICP-MS measurement and it is difficult to be washed down by 2% HNO3 soultion. We can not judge what is the interfernce. It seems related to Zn as the Zn content in WPR-1 is quite high.
We know, based on the alteration and skarn zonation, we may define the ore-forming intrusion because of contact metasomatism between wall rock and magmatic rock. However, we can’t find these geological evidence in our study area in which contain so many Pb-Zn skarn deposits. Second, lack of ore mineral such as molybdenite and alteration minerals (e.g., sericite, phlogopite or titanite) in these deposits, so it is difficult to obtain the mineralization age, even if we have already got the zircon U-Pb ages of intrusions. Therefore, is there any other way to solve this problem? Thanks very much!
I am studying amphibolites with hornblende+quartz+plagioclase+biotite+garnet+sphene+- fibrolite mineral assemblage. the quartz amount is much higher than those of plagioclase. They are as inter-layers in staurolite and andalusite schist. Their geochemical composition also show that they are of meta-sedimentary amphibolites, probably with a marl parent rock. But they have no carbonate mineral. is it possible that all of carnonate conten has been consumed to produce the above mentioned ca-bearing minerals
Hi to all!
I'm studying the Late Miocene-Early Pliocene Biogenic Bloom and I have a question: all the authors talk about a Carbon Isotope Shift that consists in an ocean wide decrease in d13C... So why Filippelli (1997, 2008) writes that there was a d13C shift toward more positive values during the bloom?
I think that I miss or I don't understand some important links between organic and inorganic carbon...
- How can chemostratigraphy be applied as a chornostratigraphic tool?
- What kind of paleoenvironmental information can be extracted from chemostratigraphy?
- What are the differences between elemental and isotope chemostratigraphy?
I want to known who is the first one put forward the concept of “porphyry deposit” The earliest paper I can get is "The porphyry copper deposits in their regional setting, in Titley, S.R., and Hicks, C.L., eds., Geology of the porphyry copper deposits, southwestern North America" Schmitt, H.A., 1966.
Who can so kind to help me?
The aim is to eliminate inorganic carbon for isotopic analysis (13C an 14C) of organic C. DOM has been concentrated by reverse osmosis from river water samples.
I have 13C samples dating from 1899 - 1946 and wish to correct them to current day values, so as to compare them to more recently obtained 13C samples. What is the suggestion correction per year/decade?
The samples are of bird feathers which feed primarily off of C3 plants,
if Lu-Hf isotopes εHf(t) values are coming positive ranging from +7.3 to +17.5 , Is This type of values only indicates that material is From Newly formed crust or contamination of both crust and Mantle source?
suggest me any pioneer paper for understanding the environment of such rocks which have these types of Lu-Hf isotopes εHf(t) values positive.
A colleague of mine has samples they would like me to run for oxygen and hydrogen analysis, but they have been preserved with a "small amount" of copper sulfate for DIC d13C analysis.
Will introducing samples with copper sulfate negatively impact the Picarro water isotope analyzer?
I am currently trying to use MAT 253 for organic carbon isotope analysis. My samples are soil carbonates, so I have to remove the inorganic carbon by HCl.
I am wondering whether it is necessary for me to neutralize the sample with distilled water before I dry my samples. Will it influence the result?
Hello, everyone, I want to discuss with you to learn about if my following thoughts are suitable for deep research.
I want to compare the content of water, especially the structural water (OH), in nominally anhydrous minerals of granulite (Khondalite: gt-sill gneiss; mafic granulite: gt-px or two px granulite), S-type granulite, plagio-granite and then to discuss the influence of structural water in NAMs on decompression melting process of Khondalite and plagio-granite. As my previous study show that the S-type granite is formed by melting of granulite facies metasedimentary rocks and pagiogranite is generated by melting of basic rocks (most possibly the basic granulite or similar kinds of rocks), and there is concensus that granulite facies metamorphism occurrs at a dry condition and the water of protolith is dehydrated before the amphibolite facies metamorphism. So, I want to know if it is a good plan to learn about how the stuctural water content of minerals in khondalite work on the melting process to produce S-type granite, and similar to the plagiogranite which is produced by melting of basic rocks.
The measured stable O18 isotopic equilibrium temperature of muscovite and biotite is 300 deg C in a metapelitic mylonite. The Ar-Ar age of dynamically recrystallized muscovite is c.11-12 Ma. Can we consider the 300 deg C temperature of muscovite as its closure temperature for Ar-Ar? What are the constraints here? Which option(s) can we further take to deduce the closure temperature of this recrystallized muscovite?
Recently, I have read a lot of paper using the log-log plot of incompatible trace elements and major elements to trace the source and magma progress of basaltic rocks. For example, the Fig. 6 of "Chemical variations and regional diversity observed in MORB" by Ricardo Arevalo Jr. and the Fig.4 of Norman et al. 1999. I will show you the pictures and these papers. I just want to know what is the basic number of log when plotting these figures?
I'm looking for published data in order to determine some kind of average value for the "crust residence time" of MOR igneous products and compare them with intra-oceanic supra subduction zone igneous products (specially data obtained using Lu-Hf isotopic system).
Is there any difference in reactivity between Ra226 and Ra228 when they react with sulfate or carbonate ions? Any reference I can use to research this? Thank you.
Injection of ferrous sulfate (approx. 3000 mg/L) for a week in anaerobic condition (i.e., iron reducing condition) showed an initial significant decrease in dissolved arsenic for about 7 months, but followed a rebound exceeding baseline. Increasing sulfate did not initiate sulfate reducing condition. DOC did not change over the time, but sulfate came into below detection (background) within 4 weeks after injection. Limited research shows that injection of lanthanum chloride under iron-reducing condition can generate lanthanum hydroxide, a supplement of ferric hydroxide. Lanthanum hydroxide has significant adsorbing capacity for dissolved arsenic and do not undergo reductive dissolution (i.e., rebound) and form stable adsorbent for dissolved arsenic once adsorbed during injection under anaerobic condition. Another research showed the opposite for lanthanum hydroxide as it leaches arsenic from solid lanthanum hydroxide under anaerobic condition. Please advise me.
RE2Zr2O7 and related oxides containing rare earth elements should be sintered at temperature ca 1500-1600oC in order to obtained pellets with high relative density. However at this temperature range RE tend to react with Al2O3 which is common materials for a crucible. What is the best way to sinter such materials? Are any powders used to separate pellet from crucible?
I am looking to have compound specific stable carbon and nitrogen isotope analysis of feather amino acids carried out. I tried UC Davis but ran into terminal permitting issues. Now I would like to find a facility in NZ or Oz to avoid such problems.
If anyone out there knows of a NZ/AUS lab carrying out CSIA I would be very grateful if you could post their name here for me so I can start enquiries.
I like to know about applications of radiometric techniques to date salt - from diagenesis to re-crystallisation during ascent / tectonic deformation.
My motivation is first to see if there are people who already work on this, have some experience or simply are interested in this topic and secondly to have something like a thread where recent applications, approaches etc. are summarized/compiled. I wonder if this will work....
I know already by quickly scanning the web that there were in the past some approaches using Ar-Ar, K-Ar and Rb-Sr... but I am questioning that the results/ages could be (always) interpreted without any doubts.
If I want to plot detrital zircon ages of Precambrian age (600 to 2500 Ma) on a probability density plot, which age (i.e. 206Pb/238U or 207Pb/206Pb) should I use? In the literature, one often encounters the recommendation that for Precambrian ages the 207Pb/206Pb age should be used. Why is this so? Does it have something to do with the common lead correction? If I do not apply such a correction to my laser-data, is it nevertheless an advantage to use the 207/206 age?
For instance, it could be recycled metasomatized oceanic lithosphere by long term storage in deep mantle. And, this is one of the major sources of mantle plumes which could metasomatize the sub-continental lithosphere by upwelling from deep mantle.
Also, can it be found in a metasomatized (enriched) lithospheric mantle by short term storage (in more shallow mantle) of subducting slab in a subduction zone or post-collisional environment (after slab break-off or delamination of a thermal boundary layer)?
In other words, can we use isotopic signatures of the EM2 mantle source in order to distinguish the possible agents of the mantle metasomatism (subduction or plume related)?
If no, How can we identify the correct metasomatism process (subduction or plume related) by using petrological methods?
I'm working on the uncertainty of water Mean transit time using stable isotopes (Oxygen 18) and Tritium. There are many assumptions to estimate the MTT which increases the uncertainty. Additionally, many errors may be considered during the estimation of MTT: measurement error, the input data function (precipitation) error and the model selection error.
Do you know how to manage it? Any suggestion?
I have some quartzites which are ductilely deformed and dynamically recrystallized. Though these quartzites contain mica (1-2%), these micas are very fine grained and difficult to be collected. Therefore, Ar-Ar method is not suitable as we think. Also no indirect method like cross-cutting leucogranites are not there in the locality to where these samples belong. In that case which method may be suitable can any body suggest?
Boninite genesis is still highly debated. Although the basic conditions (harzburgitic mantle + slab derived fluids at onset of subduction) are widely accepted, there are individual processes in different regions. I am looking for publications wich focus on the role of fractionated differentiation during petrogenesis of the papuan new guinea boninites.
Does anyone know where I can find quantitative values for the percentages of septa, theca, costa, Exodissepiment, and Endodissepiment architectural structures in various corals (or just Montastraea) Thank you very much. John Paul Jones
Measurements of natural gas samples conducted using GC-IRMS showed differences of stable hydrogen isotopes ratios between isobutane - butane and isopentane-pentane. Spreads, reach values up to 40‰ [delta notation VSMOW2]. Does anybody have an idea about isotopic fractionation induced by kerogen/oil cracking reactions? 13C signatures do not show any differences.
During evaporative condition in a closed basin, there is a high correlation between d13C and d18O of bulk carbonate. What factors that influence isotopic composition of d13C during evaporation, so that it covary with d18O.
When I measure boron isotope by MC-ICPMS, the washing time between two samples are about 10 minutes at the beginning. After about 4-5-hour measurement, the washing time rises to about half an hour which makes me crazy. So does the same problem occur in your lab and how to deal with it?
I know that mineral (e.g., chromite, olivine) chemistry yield much deeper interpretations for the chromitites and dunites, but I don’t have it.
Does somebody know a paper that explore whole-rock (XRF) geochemistry of these rocks?
We measured this Raman spectrum on a secondary mineral speleothem of a lava tube (https://www.researchgate.net/publication/265952424_RAMAN_STUDY_OF_SECONDARY_MINERALS_IN_A_RECENT_LAVA_TUBE). The main body was Thenardite and additionaly this spectrum appears occasionaly. Do you know it ?
Thanks for your help.
Conference Paper RAMAN STUDY OF SECONDARY MINERALS IN A RECENT LAVA TUBE
I need advice, explanations, articles, journals, textbooks etc. on the application of stable and trace element(unstable) isotopes and rare earth element studies on deciphering the genesis paleoenvironment and paleoclimate of ironstone deposits.
Actually, can we perform the in-situ Pb isotope system (by using MC-LA-ICP-MS) for the plagioclase and clinopyroxene minerals in the low grade metamorphosed (under the greenschist facies) basalt samples? If yes, what kind of limitations do we have because of the metamorphism effects?
In other words, to determine the possible mantle source, which pertinent minerals can be used in the same samples (low-grade met. basalts) for the in-situ Pb-Hf-Nd methods?
I wish to determine Pb-210 in sediment core sample. First I digested the sample and brought to solution. I precipitated Ba and Pb as sulphates. Ammoniacal EDTA was added to dissolve both Pb and Ba to form respective EDTA chelates. Then only BaSO4 was precipitated using acetic acid at pH 5. The supernatent containing Pb-210 was kept for Bi-210 growth for about 15 days. Then the solution was made alkaline and Ca Carrier is added with the aim of precipitating only Bi(OH)3 leaving Pb in the solution. To my surprise, I found a bulky precipitate probably calcium hydroxide. The formed hydroxide precipitate sometimes does not dissolve in 1 N nitric acid. Even if it dissolves addition of orthophosphoric acid does not precipitate bismuth phosphate. Can anyone clarify?
I want to describe a complex trophic web with primary and secondary consumers and different sources using carbon and nitrogen stables isotopes. Do I need to subtract the trophic fractionation for the secondary consumers, or I can just put in the model the raw data for both carbon and nitrogen isotopes?
Does anyone know any papers or unpublished report/s on the effect of marine water on the stable isotope signature of sub-fossil wood. I'm wanting to start an isotopic project on sub-fossil wood removed from ancient beach deposits. And my student is concerned about the effects of marine water and bacteria on the stable isotope results.