Announce your papers here
This is a placeholder forum topic where you can reply and annouce new papers on clumped isotopes. This conversation will remain a sticky, so it will always be on top of the page. I suggest you provide a link to the paper in your message.
Our paper on clumped isotope thermometry of pedogenic carbonate in the Andes has been published in EPSL.
Peters, N.A., Huntington, K.W., Hoke, G.D., 2012. Hot or not? Impact of seasonally variable soil carbonate formation on paleotemperature and O-isotope records from clumped isotope thermometry, Earth and Planetary Science Letters, doi: 10.1016/j.epsl.2012.10.024.
Budd et al. paper is out (on structural diagenesis with clumped isotopes)
Budd, D.A., Frost III, E.L., Huntington, K.W., Allwardt, P.F., (2013, in press). Syndepositional deformation features in high-relief carbonate platforms: Long-lived conduits for diagenetic fluids, J of Sed Research.
Just wanted to let you know that we have a new paper on clumped isotopes in concretions, now available as an open access PDF:
We have a new paper published on JSR that explores the origin of early dolomite in Oman using clumped isotopes and other methods:
Just in case you are interested!
Our new paper on the high-efficiency, dual-reservoir technique developed at Harvard to measure small samples has just come out in RCMS (see link below).
, and (), , , , pages –, doi: 10.1002/rcm.7022.http://onlinelibrary.wiley.com/doi/10.1002/rcm.7022/abstract
I really like getting paper updates via this forum - and realized I have not posted updates in a long time myself! So here you go with a couple of clumps papers on the Andes and Tibet out this year:
Huntington, K.W., Saylor, J., Quade, J., and Hudson, A.M. (2014) High Late Miocene-Pliocene elevation of the Zhada basin, SW Tibetan plateau, from clumped isotope thermometry. Geological Society of America Bulletin. doi:10.1130/B31000.1.
Carrapa, B., Huntington, K.W., Clementz, M., Quade, J., Bywater-Reyes, S., Schoenbohm, L.M., Canavan, R.R. (2014). Uplift of the Central Andes of NW Argentina associated with upper crustal shortening, revealed by multi-proxy isotopic analyses. Tectonics, 33, doi: 10.1002/2013TC003461.
You can get the PDFs here: http://faculty.washington.edu/kate1/Publications.html
All the best,
Kate's note served as a reminder that although I like being able to access all clumped papers in the same place, I never posted my own here.
We had quite a few papers in 2014 that can all be found here: http://people.earth.yale.edu/publications/hagit-affek
My 2 latest are a pair, for those of you interested in speleothems:
Affek H.P., Zaarur S. (2014) Kinetic isotope effect in CO2 degassing: insight from clumped and oxygen isotopes in laboratory precipitation experiments. Geochimica et Cosmochimica Acta. 143. 319-330.
Affek H.P. Ayalon A., Bar-Matthews M., Bursteyn Y., Matthews A., Zaarur S., Silberman T. (2014) Accounting for kinetic isotope effects in Soreq Cave (Israel) speleothems. Geochimica et Cosmochimica Acta. 143. 303-318.
Here is a new paper pairing clumped isotopes and magnesium isotopes in dolomite:
Geske, A., Goldstein, R.H., Mavromatis, V., Richter, D.K., Buhl, D., Kluge, T., John, C.M., Immenhauser, A., 2015. The magnesium isotope (δ26Mg) signature of dolomites, Geochmimica et Cosmochimica Acta 149 (2015), pp 131-151. doi:10.1016/j.gca.2014.11.003
All of my group's papers can be found here: http://www.carbonateresearch.com/publications
Our new paper on phosphoric acid fractionation effects on D47 is now available online.
Defliese, William F., Hren, Michael T., Lohmann, Kyger C., Compositional and Temperature Effects of Phosphoric Acid Fractionation on Δ47 Analysis and Implications for Discrepant Calibrations, Chemical Geology (2015), doi:10.1016/j.chemgeo.2014.12.018
On behalf of my coauthors, I'd like to alert you that we have a new paper on clumped isotopes in deeply buried brachiopods and other sedimentary carbonates that's now available online:
Shenton, BJ; Grossman, EL; Passey, BH; Henkes, GA; Becker, TP; Laya, JC; Perez-Huerta, A; Becker, SP; and Lawson, M. (in press) Clumped isotope thermometry in deeply buried sedimentary carbonates: The effects of bond reordering and recrystallization. GSA Bulletin.
Our high-temperature calibration paper is now "in press" and already available online.
Our review paper on applications of carbonate clumped isotope thermometry to continental tectonics is now available.
The paper focuses on applications to paleoaltimetry, basin evolution, diagenesis and structural geology studies.
Huntington, K.W., Lechler, A.R., Carbonate clumped isotope thermometry in continental tectonics, Tectonophysics
All the best,
Our paper on the effects of ions and ionic concentration on clumped isotopes is now available online:
Our paper on mixing effects has recently been published. This will probably be of most interest to those of you working on diagenetic carbonates, or any phase that is highly heterogeneous.
and (2015), Non-linear mixing effects on mass-47 CO2 clumped isotope thermometry: Patterns and implications. Rapid Commun. Mass Spectrom., 29: 901–909. doi: 10.1002/rcm.7175
We have a new paper out in Biogeosciences that might be of interest for you if you are working on vaterite:
Our method paper is out. It should be of interest to anyone using Δ47 measurements.
As always, I'd love to get your feedback, so feel free to drop me an email, especially if you're interested in relatively painless ways to reprocess "old" raw data.
Current link: <http://www.sciencedirect.com/science/article/pii/S0009254116303916>
DOI link (not yet active): <http://dx.doi.org/10.1016/j.chemgeo.2016.08.014>
Santrock vs Brand in press
Our paper "Choice of 17O correction affects clumped isotope (Δ47) values of CO2 measured with mass spectrometry" is now in press at RCM.
This paper comes after our presentation at the 5th International Clumped Isotope Workshop, St. Petersburg, Florida, titled "Is the absolute reference frame absolute? An apparent dependency of Δ47 on δ13C in CO2". This workshop facilitated the completion of our story, in particular, after lengthy discussions with Albert Colman and Gerry Olack on 17O. Thank you.
We have tow new papers published
We have published two new papers one in Terra Nova and another in Biogeosciences. The first one is on clumped isotopes in marbles from Taiwan. The second one contains clumped isotope measurements in air CO2 for a wide variety of interactions. Another will come very soon in Environmental Science and Technology in which we estimated the anthropogenic end-member for clumped and triple oxygen isotopes and used them to estimate the farction of anthropogenic CO2 in urban and sub-urban environments. I will send the link once it appears in the journal.
1.Clumped isotope composition of marbles from the Backbone Range of Taiwa
2.Clumped isotopes in near-surface atmospheric CO2 over land, coast and ocean in Taiwan and its vicinity
I should have posted this a while ago. Our paper on the clumped isotopes of Holocene pedogenic carbonates in the Chilean Andes was published in May, 2016:
Our paper on Easotope is finally out, here is the full citation (click on the title to get to the paper):
And we have yet another to announce, this time for the paleoceanographers out there:
Kelson et al. carbonate D47 calibration paper in press
The carbonate calibration companion paper to Schauer et al. (http://onlinelibrary.wiley.com/doi/10.1002/rcm.7743/abstract) is now in press and available online: http://dx.doi.org/10.1016/j.gca.2016.10.010
The citation is: Kelson J, Huntington KW, Schauer A, Saenger C, Lechler A (2016 in press). Toward a universal carbonate clumped isotope calibration: diverse synthesis and preparatory methods suggest a single temperature relationship, Geochimica et Cosmochimica Acta, doi: 10.1016/j.gca.2016.10.010.
Thanks for this interesting paper - it is a good follow-on to your presentation in St. Petersburg in January.
In reviewing this paper with my lab group, I am interested in Figure 1. It shows that the choice between Santrock or Brand can actually effect the reference frame slopes (heated gases and equilibrated gases). Our understanding of the slopes of these lines is simply whether one is adequately correcting for the proper, actual baseline (PBL). Overcorrection results in a negative slope, and ignorance results in a positive slope. Luck plus ignorance results in a near zero slope (and 5kV machines don't operate with luck, so we cannot afford ignorance as much as we'd like to). Slope is very sensitive to only a few femtoamps of current in m47.
But it is very hard for me to understand how changing the 17O correction algorithm can result in an apparent change in the background values that would elicit a change of slope illustrated in Figure 1 of this paper. Is our understanding of the slope too simplistic? How does a change in 17O correction manifest itself in the slope of these lines?
To us, the most interesting part of the paper is figure 4, which shows how the value of the reference gas can effect the sensitivity of measurements to 17O correction. We happen to have a reference gas that puts us in a really good spot, and we are not sensitive to these changes. We discussed the importance of reference gas values in our 2013 RCMS paper, and this figure seems to corroborate some of what we had observed. But we cannot readily observe the sensitive changes in values that Schauer et al note using the Santrock algorithm for 17O correction and we have to lean on the calculations rather than direct measurements.
Re: Brad's question above, the gas lines can have a non-zero slope because of a wrong background value, and/or because of inaccurate 17O correction parameters (and these two sources of non-zero slope are pretty much additive). That's because using different 17O parameters affects the raw D47 value in a way that varies linearly with d18O and d13C. Since d47 is roughly equal to d13C+d18O, the net effect on raw D47 varies linearly with d47, which will manifest as a change in gas slope. For a more detailed description, please see figs 5 and 6 in our own recent paper (<http://dx.doi.org/10.1016/j.chemgeo.2016.08.014>)
Thank you, Brad. We were able to complete this story because of the Workshop in St. Petersburg in January, so thank you for hosting!
Thank you, Mathieu, for answering, Brad's first question.
Regarding your second point, Brad, on Figure 4, I would love to hear what conditions yield a lack of sensitivity. If you are running as in your 2013 paper, then I have often wondered if this quoted situation would give rise to a lack in sensitivity:
"Aliquots of CO2 from different carbonate sources and compressed gas bottles were added and equilibrated..." (Rosenheim et al. , RCM, 2013)
It could be that by generating a reference frame with a variety of CO2 for your CO2/H2O equilibrations and your heated gases (and hence a variety of 13C compositions), you remove the effect we are observing when we construct our reference frame (both CO2/H2O equilibrations and heated gases) with a single CO2 (FC or FF). Other labs too describe making CO2/H2O equilibrations with a single CO2 but create their heated gases by grabbing samples back out of the mass spec and heating them (and thus obtaining a range in 13C compositions at least fo the heated gases).
I know Albert Colman is working on a paper regarding 17O influence on D47. With our paper, Mathieu's, and Albert's, along with the upcoming workshop, perhaps we can work out more of the details and see who observes this and who doesn't and why.
Just a recap for the newbies.
The PBL correction is the main one to get right. The linear correction, D47 vs d47, is a good first order approximation of the problem and works well if the baseline offset is small. But as you go further apart in d47 to get a better D47 vs d47 line, you'll introduce a larger artifact--the approximation does not hold as well over large d47 spreads. (See papers by He, et al., and Bernasconi, et al.)
As discussed above Andy and Matthieu have both done some really nice work looking at 17O. I think its great we can even have conversations about issues in the 20 ppm range. We seem to see variations in what 17O parameter set works best depending on mass spec conditions. Bummer.
In model studies with varying both 13C and 18O, the error introduced by using an incorrect 17O correction will mainly look like a shot gun pattern with a slight trend. The line seen in 13C space is spread out along the line seen in 18O space. As presented at Goldschmidt, we've observed that that pattern can collapse down onto a line if you plot D47 against (d13C-d18O). This works well if you are comparing the 2010 recommendations to the 1995 (Gonfiantini) ones. It does not work as well when comparing the 2010 set with Santrock, Studley and Hayes. But another tool for the tool box--and it works with measured data.
And I should note, if your standards do not vary much in (d13C- d18O) space, then you will not see a relative difference between processing them using the 1995 parameter set or using the 2010 set. If your samples are in the same space too, then they won't vary after correction to the standards. If the sample are in a different (d13C - d18O) space, their results will vary. I mention this because different groups may or may not see a problem--and all will be right.
As a community, we might want to settle on a method for how to generate 18R from raw data. Brand et al. recommendation makes an approximation so you can avoid iterations when trying to solve 0= -3* 17R^2 + 2*45R*17R + 2*18R - 46R, but with some error introduced in the 13C values--which will affect D47 too.
p.s.Sorry for the longish post--and associated references (so it will be longer):
Bernasconi, S.M., Hu, B., Wacker, U., Fiebig, J., Breitenbach, S.F.M., Rutz, T., 2013. Background effects on Faraday collectors in gas-source mass spectrometry and implications for clumped isotope measurements. Rapid Commun. Mass Spectrom. 27, 603–612. doi:10.1002/rcm.6490
He, B., Olack, G.A., Colman, A.S., 2012. Pressure baseline correction and high-precision CO2 clumped-isotope (∆47) measurements in bellows and micro-volume modes. Rapid Commun. Mass Spectrom. 26, 2837–2853. doi:10.1002/rcm.6436
Daëron, M., Blamart, D., Peral, M., Affek, H.P., 2016. Absolute isotopic abundance ratios and the accuracy of Δ47 measurements. Chemical Geology 442, 83–96. doi:10.1016/j.chemgeo.2016.08.014
Schauer, A.J., Kelson, J., Saenger, C., Huntington, K.W., 2016. Choice of 17O correction affects clumped isotope (Δ47) values of CO2 measured with mass spectrometry. Rapid Commun. Mass Spectrom. 30, 2607–2616. doi:10.1002/rcm.7743
Huntington, K.W., Eiler, J.M., Affek, H.P., Guo, W., Bonifacie, M., Yeung, L.Y., Thiagarajan, N., Passey, B., Tripati, A., Daëron, M., Came, R., 2009. Methods and limitations of “clumped” CO2 isotope (Δ47) analysis by gas-source isotope ratio mass spectrometry. J. Mass Spectrom. 44, 1318–1329. doi:10.1002/jms.1614
Thanks for chiming in, Gerry.
I'd like to note that the 18O calculation in appendix A of our paper uses the same basic idea as Brand et al. (2010), but we push it one degree further (second-degree polynomial approximation rather than first-degree). As a result, the approximation remains well below 0.00002 permil for d13C and d18O for all values between -50 and +50 permil. I trust this should be good enough for now?
For anybody wishing to test it, here is the Excel spreadsheet from the supplemental material: <https://www.dropbox.com/s/nvnxz4zdpn03zlv/D47lib.xlsx?dl=1>.
I do not understand your sentence : As presented at Goldschmidt, we've observed that that pattern can collapse down onto a line if you plot D47 against (d13C-d18O). This works well if you are comparing the 2010 recommendations to the 1995 (Gonfiantini) ones. It does not work as well when comparing the 2010 set with Santrock, Studley and Hayes. Can you please elaborate of what works or doesn't work and why Gonfiantini yes but SSH no, as they are closer to each other than to Brand.
Another question to everybody:
Did anybody try using Mathieu's equations and / or template to recalculate old data? I recalculated my measurements of ETH1-4 and got only a small difference ebtween SSH/Gonfiantini vs Brand (up to 0.003‰). But in calculating the Zaarur et al calibration data the difference is large (0.021‰ on average and between 0.012 to 0.033‰ with no obvious trend). As the Zaarur samples are light in d13C, this leads to an issue of how come biogenic (heavy d13C) and synthetics measured in the same lab agree in D47. In other words, the recalculated Zaarur line makes no sense. I imagine Denis and Schrag will look the same but didn't calculate it.
The issue becomes even more confusing (to me at least) when looking at the comparison between Zaarur recalculated by Mathieu and Kelson 2016 data (I think this is figure 6 in Kelson et al). There the offset is small. But if you look carefuly you'll notice that there is a difference between SSH and Brand, but that Kelson / Daeron recalculated Zaarur in SSH is different than the original SSH.
Either something is wrong in the equation or this calculation is highly sensitive to something that mathieu and me are doing differently with the same data - maybe the way we acount for variability in the ETF over time. I do not know.
I wonder if anybody recalculated their data and saw strange outcomes.