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2021
Bright, J., Ebert C., KOSNIK M. A. T. T. H. E. W. A., Southon J. R., Whitacre K., Albano P. G., Flores C., Frazer T. K., Hua Q., Kowalewski M., Martinelli J. C., Oakley D., Parker W. G., Retelle M., RITTER M. A. T. I. A. S. D. O. N. A. S. C. I. M. E. N. T. O., Rivadeneira M. M., Scarponi D., Yanes Y., Zuschin M., & KAUFMAN D. A. R. R. E. L. L. S. (2021).  COMPARING DIRECT CARBONATE AND STANDARD GRAPHITE 14C DETERMINATIONS OF BIOGENIC CARBONATES. Radiocarbon. 1-17., 2021: Cambridge University Press AbstractWebsite

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The direct carbonate procedure for accelerator mass spectrometry radiocarbon (AMS 14C) dating of submilligram samples of biogenic carbonate without graphitization is becoming widely used in a variety of studies. We compare the results of 153 paired direct carbonate and standard graphite 14C determinations on single specimens of an assortment of biogenic carbonates. A reduced major axis regression shows a strong relationship between direct carbonate and graphite percent Modern Carbon (pMC) values (m = 0.996; 95% CI [0.991–1.001]). An analysis of differences and a 95% confidence interval on pMC values reveals that there is no significant difference between direct carbonate and graphite pMC values for 76% of analyzed specimens, although variation in direct carbonate pMC is underestimated. The difference between the two methods is typically within 2 pMC, with 61% of direct carbonate pMC measurements being higher than their paired graphite counterpart. Of the 36 specimens that did yield significant differences, all but three missed the 95% significance threshold by 1.2 pMC or less. These results show that direct carbonate 14C dating of biogenic carbonates is a cost-effective and efficient complement to standard graphite 14C dating.

2020
Frozza, C. F., Pivel M. A. G., Su J. Y., do Ritter M. N., & Coimbra J. C. (2020).  Bioerosion on late Quaternary planktonic Foraminifera related to paleoproductivity in the western South Atlantic. , 2020/06/04/: PANGAEA AbstractWebsite

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These datasets include the relative abundances of planktonic foraminifera, relative abundances of drilled specimens, stable isotope data and age model results of sediment core SAT-048A.

Frozza, C. F., Pivel M. A. G., Suárez-Ibarra J. Y., Ritter M. N., & Coimbra J. C. (2020).  Bioerosion on late Quaternary planktonic Foraminifera related to paleoproductivity in the western South Atlantic. Paleoceanography and PaleoclimatologyPaleoceanography and Paleoclimatology. n/a(n/a), e2020PA003865., 2020: John Wiley & Sons, Ltd AbstractWebsite

doi: 10.1029/2020PA003865

Key Points: For the first time, drill holes in planktonic Foraminifera from the western South Atlantic were compared with paleoceanographic proxies. Paleoproductivity of the western South Atlantic was reconstructed using assemblage and geochemical indexes for the last 46 kyr. Paleoproductivity estimates and bioerosion rates of planktonic foraminiferal tests show a strong relation during late Quaternary.

2016
do Ritter, M. N., Francischini H., Kuhn L. A., da Luz N. C., Michels F. H., de Morais A. L. M., Paim P. A. V., Xavier P. L. A., & de Francesco C. G. (2016).  El sesgo del operador en la replicabilidad de los estudios tafonómicos comparativos. Revista Brasileira de Paleontologia. 19, 449–464., jan, Number 3: Sociedade Brasileira de Paleontologia AbstractWebsite

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do Ritter, M. N., Francischini H., Kuhn L. A., Da Luz N. C., Michels F. H., de Morais A. L. M., Paim P. A. V., Xavier P. L. A., & de Francesco C. G. (2016).  {Operator and replicability bias in comparative taphonomic studies}. : PANGAEA Abstract

Supplement to: Ritter, MN et al. (2016): Los sesgos del operador y de la replicabilidad en los estudios tafonómicos comparativos. Revista Brasileira de Paleontologia, 19(3), 449-464, https://doi.org/10.4072/rbp.2016.3.10

The operator effect is a well-known analytical bias already quantified in some taphonomic studies. However, the influence of operator bias in the replicability on taphonomic studies has still not been considered. Here, we quantified for the first time this bias using different multivariate statistical techniques, testing if the operator effect is related to the replicability. We analyzed the results reported by 15 operators working on the same dataset. Each operator analyzed 30 bioclasts (bivalve shells) by site, from a total of five sites, considering the following taphonomic attributes: shell fragmentation, edge rounding, corrasion, bioerosion, and color alteration. The operator effect followed the same pattern reported in previous studies, characterized by a worse correspondence for those attributes having more than two levels of damage categories. However, the effect did not appear to have relation to replicability, because nearly all operators found differences among sites. The binary attribute bioerosion exhibited 83{%} of correspondence among operators, but at the same time, it was the taphonomic attribute that showed the highest dispersion among operators (28{%}). Therefore, we concluded that binary attributes, despite indicating a reduction of the operator effect diminishes replicability, result in different interpretations of concordant data. We found that a variance value of nearly 8{%} among operators was enough to generate a different taphonomic interpretation, in a Q-mode cluster analysis. The results reported here showed that the statistical method employed influences the level of replicability and comparability of a study and that the availability of results may be a valid alternative to reduce bias.