Dr Janaína Ávila is a research fellow at the Australian National University (ANU). In 2011, she received her PhD in isotope cosmochemistry from the Research School of Earth Sciences (RSES, ANU). During her PhD research, she developed new protocols for measuring heavy isotopes (U, Th, Pb, W, Ba, Eu) in situ in presolar stardust SiC grains using the SHRIMP ion microprobe. Most of this work was carried out at RSES (ANU) under the supervision of Prof. Trevor Ireland, but she also had the opportunity to closely work with Prof. Ernst Zinner at Washington University in St. Louis, carrying out C, N, and Si isotope measurements with a NanoSIMS 50, and with Dr. Maria Lugaro from Monash University on s-process nucleosynthetic signatures.
Since her PhD award, Dr Ávila has held postdoctoral fellowships at the Astronomy Department, University of São Paulo, where she continued research on nucleosynthetic signatures of heavy elements in AGB stars, and then at RSES-ANU, first as a Researcher in Business Postdoctoral Fellow and then as a research fellow. Dr Ávila research centres around the application of ion microprobes to the understanding of the isotopic nature of solar and presolar materials at the microscale. Dr Ávila is particularly interested in presolar grains recovered from primitive meteorites and the scientific implications of their isotopic signatures to the understanding of the origin of the elements and the chemical evolution of the galaxy and solar neighbourhood. Current interests include: (1) isotopic signatures of nucleosynthetic processes that occur inside stars, (2) environmental and biological evolutions on early Earth, and (3) factors influencing isotopic fractionation (mass-dependent and mass-independent fractionation) associated to sulfur and oxygen isotopes.
- Development and applications of secondary ion mass spectrometry within the planetary sciences
- Stable isotopes
- Cosmochemistry and Cosmochronology
- Meteorites and stardust grains
Multiple sulfur isotope analysis of sedimentary pyrites with SHRIMP-SI: unravelling complex depositional and post-depositional processes
The sulfur isotopic record of Archean and Paleoproterozoic sedimentary rocks places important constraints on the timing of atmospheric oxygenation. However, many of these ancient rocks have endured several post-depositional processes (e.g., diagenetic, magmatic, hydrothermal, and metamorphic) over geological time so that the original isotopic signature from the early atmosphere and biosphere is now largely overprinted. In situ SHRIMP-SI measurements of multiple sulfur isotopes (32S, 33S, 34S, 36S) in pyrite now allow Δ33S to be determined with internal errors better than 0.05‰ (2SE) and reproducibility about 0.1‰ (2SD). Charge mode measurements  of 36S− allow Δ36S values to be determined with internal precisions of ± 0.2‰ (2SE) and reproducibility better than 0.25‰ (2SD). This level of precision permits identification, at the micron scale, of preserved isotopic signatures of ancient atmospheric chemical and biological activity, as well as overprinted secondary processes.
Measurements of oxygen isotope ratios with the new SHRIMP-SI: high precision analyses of zircon reference materials
The potential for oxygen isotopic analysis of zircon (ZrSiO4) has been recognized for quite some time. Due to its refractory nature and widespread occurrence in many geological environments, zircon d18O values offer unique insights into a wide range of geological processes. The recently commissioned SHRIMP-SI has been designed to be capable of levels of precision similar to conventional oxygen isotope bulk analysis, while maintaining the in situ relationship that is essential for the documentation and interpretation of geological samples. In order to assess SHRIMP-SI instrument performance, oxygen isotopic analyses have been carried out on a suite of zircon reference materials, many of which have been used previously for U-Pb and/or oxygen isotope standardization. We have been able to achieve analytical sessions with measurement stability of better than 0.3 ‰ (95% confidence level). Analyses of common reference materials (Mud Tank, FC1, Temora, R33) typically yield the expected offsets within 0.1 ‰.
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 Ireland T.R., Ávila J.N., Lugaro M., Cristallo S., Holden P., Lanc P., Nittler L., Alexander C.M.O'D., Gyngard F., Amari S. 2017. Rare earth element abundances in presolar SiC. Geochimica et Cosmochimica Acta, in press.
 Babinski M., Rapela C.W., Ávila J.N (eds). 2016. 50 years of isotope geology in South America. Brazilian Journal of Geology 46.
 Ireland T.R., Schram N., Holden P., Lanc., Ávila J.N., Armstrong R., Amelin Y., Latimore D., Corrigan., Clement S., Foster J.J., Compston W. 2014. Charge-mode electrometer measurements of S-isotopic compositions on SHRIMP-SI. International Journal of Mass Spectrometry 359, 26-37.
 Ávila J.N., Ireland T.R., Gyngard F., Zinner E., Mallmann G., Lugaro M., Holden P., Amari S. 2013. Barium isotopic compositions in stardust SiC grains from the Murchison meteorite: Insights into the stellar origins of large SiC grains. Geochimica et Cosmochimica Acta 120, 628-647.
 Ávila J.N., Ireland T.R., Lugaro M., Gyngard F., Zinner E., Cristallo S., Holden P., Rauscher T. 2013. Europium s-process signature at close-to-solar metallicity in stardust SiC grains from AGB stars. Astrophysical Journal Letters 768, L18 (7p).
 Ávila J.N., Lugaro M., Ireland T.R., Gyngard F., Zinner E., Cristallo S., Holden P., Buntain J., Amari S., Karakas, A.I. 2012. Tungsten isotopic compositions in stardust SiC grains from the Murchison meteorite: Constrains on the s-process in the Hf-Ta-W-Re-Os region. Astrophysical Journal 744, 49 (13p).
 Barredo S., Chemale Jr. F., Marsicano C., Ávila J.N., Ottone E.G., Ramos V.A. 2012. Tectono-sequence stratigraphy and U-Pb zircon ages of the Rincon Blanco depocenter, Northern Cuyo Rift, Argentina. Gondwana Research 21,624-636.
 Mancuso A.C., Chemale F., Barredo S., Ávila J.N., Ottone E.G., Marsicano C. 2010. Age constraints for the northernmost outcrops of the Triassic Cuyana Basin, Argentina. Journal of South American Earth Sciences 30, 97-103.
 Heck P.R., Gyngard F., Ott U., Meier M.M.M., Ávila J.N., Amari S., Zinner E., Lewis R.S., Bauer H., Wieler R. 2009. Interstellar residence times of presolar SiC dust grains from the Murchison Carbonaceous meteorite. Astrophysical Journal 698, 1155-1164.
 Mallmann G., Chemale Jr. F., Ávila J.N., Kawashita K., Armstrong R.A., 2007. Isotope geochemistry and geochronology of the Nico Perez Terrane, Rio de la Plata Craton, Uruguay. Gondwana Research 12, 489-508.
 Ávila J.N., Chemale Jr. F., Mallmann G., Kawashita K., Armstrong R.A., 2006. Combined stratigraphic and isotopic studies of Triassic strata, Cuyo Basin, Argentine Precordillera. Geological Society of America Bulletin 118, 1088-1098.
 Ávila J.N., Chemale Jr. F., Mallmann G., Borba, A.W., Luft, F.F., 2005. Thermal evolution of inverted basins: Constraints from apatite fission track thermochronology in the Cuyo Basin, Argentine Precordillera. Radiation Measurements 39, 603-611.
 Luft F.F., Luft Jr J.L., Chemale Jr F., Vignol-Lelarge M.L.M., Ávila J.N. 2005. Post-Gondwana break-up record constraints from apatite fission track thermochronology in NW Namibia. Radiation Measurements 39, 675-679.