Columbia River basalts; Karoo ignous province; eruption dynamics; micro-baddeleyite; micro-zircon; U-Pb dating; Large Igneous Province; Central Atlantic Magmatic Province; basalt; geochronology; environmental perturbation
Davies J. H. F. L., Marzoli A., Bertrand H., Youbi N., Ernesto M., Greber N. D., Ackerson M., Simpson G., Bouvier A.-S., Baumgartner L., Pettke T., Farina F., Ahrenstedt H. V., Schaltegger U. (2021), Zircon petrochronology in large igneous provinces reveals upper crustal contamination processes: new U–Pb ages, Hf and O isotopes, and trace elements from the Central Atlantic magmatic province (CAMP), in Contributions to Mineralogy and Petrology
, 176(1), 9-9.
Farina Federico, Dini Andrea, Davies Joshua H.F.L., Ovtcharova Maria, Greber Nicolas D., Bouvier Anne-Sophie, Baumgartner Lukas, Ulianov Alexey, Schaltegger Urs (2018), Zircon petrochronology reveals the timescale and mechanism of anatectic magma formation, in Earth and Planetary Science Letters
, 495, 213-223.
Bindeman I. N., Zakharov D. O., Palandri J., Greber N. D., Dauphas N., Retallack G. J., Hofmann A., Lackey J. S., Bekker A. (2018), Rapid emergence of subaerial landmasses and onset of a modern hydrologic cycle 2.5 billion years ago, in Nature
, 557(7706), 545-548.
Davies J.H.F.L., Stern R.A., Heaman L.M., Moser D.E., Walton E.L., Vennemann T. (2018), Evaluating baddeleyite oxygen isotope analysis by secondary ion mass spectrometry (SIMS), in Chemical Geology
, 479, 113-122.
Callegaro Sara, Marzoli Andrea, Bertrand Hervé, Blichert-Toft Janne, Reisberg Laurie, Cavazzini Giancarlo, Jourdan Fred, Davies Joshua, Parisio Laura, Bouchet Romain, Paul André, Schaltegger Urs, Chiaradia Massimo (2017), Geochemical Constraints Provided by the Freetown Layered Complex (Sierra Leone) on the Origin of High-Ti Tholeiitic CAMP Magmas, in Journal of Petrology
, 58(9), 1811-1840.
Greber Nicolas D., Dauphas Nicolas, Bekker Andrey, Ptáček Matouš P., Bindeman Ilya N., Hofmann Axel (2017), Titanium isotopic evidence for felsic crust and plate tectonics 3.5 billion years ago, in Science
, 357(6357), 1271-1274.
Zakharov D.O., Bindeman I.N., Slabunov A.I., Ovtcharova M., Coble M.A., Serebryakov N.S., Schaltegger U. (2017), Dating the Paleoproterozoic snowball Earth glaciations using contemporaneous subglacial hydrothermal systems, in Geology
, 45(7), 667-670.
Davies J.H.F.L., Marzoli A., Bertrand H., Youbi N., Ernesto M., Schaltegger U. (2017), End-Triassic mass extinction started by intrusive CAMP activity, in Nature Communications
, 8, 15596.
Marzoli A., Davies J.H.F.L., Youbi N., Merle R., Dal Corso J., Dunkley D.J., Fioretti A.M., Bellieni G., Medina F., Wotzlaw J.F., McHone G., Font E., Bensalah M.K. (2017), Proterozoic to Mesozoic evolution of North-West Africa and Peri-Gondwana microplates: Detrital zircon ages from Morocco and Canada, in Lithos
, 278-281, 229-239.
Dramatic environmental perturbation, climate overturn and mass extinctions in the geological past are considered to be caused by massive volcanic activity in Large Igneous Provinces (LIPS). We have previously demonstrated that in selected cases, catastrophic biotic change and dynamics and tempo of biotic post-extinction recovery can be dated at ± 100 ka uncertainty of the 206Pb/238U zircon date, e.g., in the Mesozoic. It is of primordial importance that the volcanic activity of LIPS associated with these biotic crises is dated at identical levels of precision and accuracy, in order to infer a causal relationship. In the frame of precursor project 200021_146994 we demonstrated that baddeleyite and zircon are astonishingly ubiquitous in coarse-grained basalt, if the sampling strategy is adapted to this purpose. In this present project proposal we intend to apply the newly developed high-precision U-Pb dating of micro-zircon (ZrSiO4) and micro-baddeleyite (ZrO2) to volcanic rocks from three Large Igneous Provinces (LIPS): (1) Establish a high-resolution correlation of the Central Atlantic Magmatic Province (CAMP) volcanism between Morocco and Bay of Fundy (Canada), and comparison with existing high-precision data for the end-Triassic mass extinction, and with cyclostratigraphic and magnetostratgraphic timescales; (2) High-precision dating of the duration of the Columbia River Basalt (CRB) province, using this province as a show case for estimating magma flux and temporal evolution of magma sources over time, and intercalibration with the paleomagnetic timescale; (3) Temporal calibration of the long-lived Karoo province in Lesotho/South Africa through dating of sills, dykes and basaltic lavas, and intercalibration with the paleomagnetic time-scale, in order to explain multi-pulsed and oscillating biodiversity changes throughout the Toarcian.The high-precision U-Pb dating of smallest grains of magmatic zircon and baddeleyite will yield age results at a 50 - 100 ka level of precision and accuracy, insured by our unprecedented sensitivity of our analytical techniques. By avoiding the widely used 40Ar/39Ar chronometer, we avoid the necessity to propagate systematic uncertainties associated with decay constants and standard or tracer compositions, respectively, into the final dates due to the comparison of two decay schemes, and therefore can compare dates at the level of analytical precision. In addition, analysis of trace elemental composition and Hf isotopes from the same dated volume of these minerals will allow us to gain information about the evolution of the melts sources over time, to interpret accurately the U-Pb data and especially trace post-crystallization open-system behavior of baddeleyite. In addition, oxygen isotope analysis through secondary ion mass spectrometry will be developed as a proxy for tracing and quantifying post-crystallization Pb loss in baddeleyite. The trace element and Hf isotopic part of the analytical work is very challenging and needs further development of analytical techniques.In conclusion, the project will provide the following new knowledge:1.Establish absolute durations of volcanic activity at high resolution, reconstruct the eruption dynamics of different LIPS (CAMP, CRB and Karoo) and interpret them in terms of plate tectonics.2.Analytical techniques for dating micro-zircon and -baddeleyite in mafic rocks at better than ±0.1% precision of their 206Pb/238U age, together with trace element, oxygen and hafnium isotopic characteristics.3.Correlate these high-precision dates with magneto- and cyclostratigraphic timescales, as well as with marine environmental and biotic crises recorded in marine sedimentary sequences. These data may discriminate between models of pre-volcanic peak extinction versus maximum environmental stress and extinction during the peak volcanic activity.