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Temporal calibration of eruption dynamics of Large Igneous Provinces and correlation with global environmental disturbance and biotic response by high-precision U-Pb dating of micro-baddeleyite

English title Temporal calibration of eruption dynamics of Large Igneous Provinces and correlation with global environmental disturbance and biotic response by high-precision U-Pb dating of micro-baddeleyite
Applicant Schaltegger Urs
Number 146994
Funding scheme Project funding
Research institution Département des sciences de la Terre Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Geochronology
Start/End 01.01.2014 - 31.12.2015
Approved amount 248'807.00
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Keywords (12)

Karoo ignous province; environmental perturbation; Large Igneous Province; eruption dynamics; Central Atlantic Magmatic Province; U-Pb dating; mass extinction; Toarcian oceanic anoxic event; micro-baddeleyite; basalt; Triassic Jurassic boundary; geochronology

Lay Summary (German)

Lead
Perioden von Massenaussterben in der Erdgeschichte wurden von Vulkanausbrüchen in grossen vulkanischen Provinzen verursacht. Wie lange dauerten diese Perioden von Vulkanismus, und können wir mit Hilfe von ultrapräzisre U-Pb Datierung eine zeitliche Koinzidenz zwischen Vulkanismus und den klimatischen Veränderungen herstellen, welche zu den Massenaussterben geführt hat?
Lay summary

Vulkanausbrüche in sogenannten "Grossen Vulkanprovinzen" haben zu verschiedenen Zeiten in der geologischen Geschichte zu globalen Störungen des Klimas und des Lebens geführt. Im Extremfalle wurde das Leben um 80 bis 90% reduziert, als "Massensterben" benannt, wie zum Beispiel an der Perm/Trias Grenze (vor 252 Millionen Jahren), oder an der Trias/Jura Grenze (vor 201 Millionen Jahren). Die zeitliche Koinzidenz zwischen vulkanischer Aktivität und der klimatischen und biotischen Reaktion auf der Erde kann nur mit genauer Geochronologie, das heisst mit Altersbestimmungen, hergestellt werden.

Dieses Projekt soll hochpräzise U-Pb Altersbestimmungen an kleinsten Körnern der Mineralien Zirkon und Baddeleyit entwickeln, um basaltische Gesteine dieser Vulkanprovinzen direkt datieren zu können. Dies war mit den bestehenden Methoden bisher nicht möglich, wird jedoch jetzt aufgrund analytischer Entwicklungen im geochronologischen Labor der Universität Genf möglich. Mit Hilfe dieser Altersbestimmungen, inklusive der Analyse von Spurenelementen und der Isotopenzusammensetzung des Elements Hafnium, kann die petrologische Entwicklung eines solchen vulkanischen Zentrums im Laufe seiner Aktivität rekonstruiert werden. Die Karoo Provinz ist beispielsweise während etwa 10 Millionen Jahren aktiv, die mittel-atlantische Provinz nur während 500'000 Jahren. Unterscheiden sich die Schmelzen in ihrer Herkunft zwischen den beiden Provinzen, ist die Tiefe der Aufschmelzung im Mantel verschieden oder der Aufschmelzungsgrad, verändern sie sich während der Aktivität?

Die geplanten Forschungsarbeiten werden zu ganz neuen Erkenntnissen sowohl auf dem Gebiete der globalen klimatischen Veränderungen in der Erdgeschichte, als auch in der Kenntnis der Struktur des Erdmantels führen.

Direct link to Lay Summary Last update: 23.09.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Linking the thermal evolution and emplacement history of an upper-crustal pluton to its lower-crustal roots using zircon geochronology and geochemistry (southern Adamello batholith, N. Italy)
Broderick C., Wotzlaw J.F., Frick D.A., Gerdes A., Ulianov A., Günther D., Schaltegger U. (2015), Linking the thermal evolution and emplacement history of an upper-crustal pluton to its lower-crustal roots using zircon geochronology and geochemistry (southern Adamello batholith, N. Italy), in Contributions to Mineralogy and Petrology, 170(3), 28.
Megacrystic zircon with planar fractures in miaskite-type nepheline pegmatites formed at high pressures in the lower crust (Ivrea Zone, southern Alps, Switzerland)
Schaltegger U., Ulianov A., Müntener O., Ovtcharova M., Peytcheva I., Vonlanthen P., Vennemann T., Antognini M., Girlanda F. (2015), Megacrystic zircon with planar fractures in miaskite-type nepheline pegmatites formed at high pressures in the lower crust (Ivrea Zone, southern Alps, Switzerland), in American Mineralogist, 100(1), 83-94.
The Bushveld Complex was emplaced and cooled in less than one million years - results of zirconology, and geotectonic implications
Zeh A., Ovtcharova M., Wilson A.H., Schaltegger U. (2015), The Bushveld Complex was emplaced and cooled in less than one million years - results of zirconology, and geotectonic implications, in Earth and Planetary Science Letters, 418, 103-114.
High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early-Middle Cambrian (Stage 4-5) extinction
Jourdan F., Hodges K., Sell B., Schaltegger U., Wingate M.T.D., Evins L.Z., Söderlund U., Haines P.W., Phillips D., Blenkinsop T. (2014), High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early-Middle Cambrian (Stage 4-5) extinction, in Geology, 42(6), 543-546.
Mass spectrometry in earth sciences: The precise and accurate measurement of time
Schaltegger U., Wotzlaw J.-F., Ovtcharova M., Chiaradia M., Spikings R. (2014), Mass spectrometry in earth sciences: The precise and accurate measurement of time, in Chimia, 68(3), 124-128.

Collaboration

Group / person Country
Types of collaboration
Curtin University, Perth Australia (Oceania)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Università di Padova Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
University of Lausanne Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Swiss Geoscience Meeting 2015 Talk given at a conference Identifying and understanding Pb loss in baddeleyite 20.11.2015 Basel, Switzerland Davies Joshua; Schaltegger Urs;
Goldschmidt Conference Talk given at a conference Assessing the long-term reproducibility of high-precision ID-TIMS U-Pb data 16.08.2015 Prag, Czech Republic Davies Joshua; Schaltegger Urs;
GAC-MAC-GSA Joint Assembly Talk given at a conference New insights into the relationship between the Central Atlantic Magmatic Province (CAMP) and the End-Triassic extinction from CAMP U-Pb zircon and baddeleyite dates 03.05.2015 Montreal, Canada Davies Joshua; Schaltegger Urs;
EGU General Assembly 2015 Talk given at a conference Exploring the pre-eruptive history of the Central Atlantic Magmatic Province (CAMP) and the link with the end Triassic extinction using high precision U-Pb zircon and baddeleyite geochronology 13.04.2015 Vienna, Austria Schaltegger Urs; Davies Joshua;
AGU Fall Meeting 2014 Talk given at a conference Looking through the zircon kaleidoscope: durations, rates, and fluxes in silicic magmatic systems 15.12.2014 San Francisco, United States of America Schaltegger Urs;


Associated projects

Number Title Start Funding scheme
162341 Temporal calibration of eruption dynamics of Large Igneous Provinces and correlation to global environmental disturbance with high-precision U-Pb dating of micro-zircon and -baddeleyite 01.01.2016 Project funding
137630 Establishing globally valid tie points for intercalibration of biochronologic and radioisotopic timescales between the latest Permian and middle Jurassic using high-precision U-Pb dating of volcanic ash beds 01.12.2011 Project funding
126500 Precise and accurate dating of periods of biotic crisis and recovery in the Earth's history using zircon U-Pb dating of volcanic ash beds. 01.12.2009 Project funding

Abstract

High-precision and high-accuracy U-Pb dates of volcanic zircon from ash beds provide invaluable information for the temporal quantification of environmental perturbation and biotic response in the geological past. We have previously demonstrated that in selected cases, catastrophic biotic change as well as post-extinction biological recovery, and dynamics and tempo of biotic post-extinction recovery can be dated with better than ± 100 ka uncertainty of the 206Pb/238U zircon date. In the present project we aim to develop high-precision U-Pb dating of the mineral baddeleyite (ZrO2) in basalts from Large Igneous Provinces (LIP's), such as the Central Atlantic Magmatic Province (CAMP) or the Karoo igneous province. These two huge volcanic systems are thought to be the triggers for the end-Triassic climatic deterioration and mass extinction, and the early Toarcian global marine anoxia, respectively. High-precision U-Pb dating of magmatic baddeleyite in these basalts will allow temporal cross-calibration between volcanism on one hand, and global environmental and biotic disturbance on the other hand at a 50 - 100 ka level of precision and accuracy. 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, we plan to analyze trace elements and Hf isotopes from the same dated volume of baddeleyite, for helping with the detailed interpretation of the U-Pb dates, and for gaining information about the melt source. We also intend to explore oxygen isotope analysis as a tool to quantify the degree of post-crystallization open-system behaviour of baddelyite grains.Separation and isotopic analysis of 20-40 µm small baddeleyite grains from basalts will be challenging and will request several efforts in adapting existing and developing new techniques in our laboratory. We anticipate that a majority of basalts will show a certain amount micro-baddeleyites, or, in case of more evolved compositions, of micro-zircon. The newly developed techniques will be applied to two cases: 1) The high-resolution intercalibration between the very short-lived CAMP volcanism in Morocco, US and Canada, with existing high-precision data for the environmental perturbation at the end of the Triassic causing mass extinction; and 2) the intercalibration between the lower Toarcian marine anoxic event with the eruption dynamics of the long-lived Karoo igneous province in Lesotho/South Africa. Basalts will be sampled from sections that are well characterized in terms of the paleomagnetism, sample selection is therefore carried out in close collaboration with specialists from France, Italy, The Netherlands and Australia. By high-precision dating some important paleomagnetic reversals of global importance will be calibrated to better than ±50 to 100 ka. Total durations of LIP volcanism, as well as their eruption dynamics over time will be reconstructed with high-precision methods by the first time. In conclusion, the project will deliver the following new knowledge about Earth's history:1.Establish absolute durations of volcanic activity at high resolution and reconstruct the eruption dynamics of two fundamentally different LIP's: CAMP (single activity peak of short duration) and Karoo (multi-peak activity over an extended period of time).2.Offer a new approach for dating basalt flows at ± 50-100 ka precision, which allows to directly date eruption dynamics of LIP's. Together with the obtained Hf isotope information from dated baddeleyite and potentially from geochemical information from whole rocks, the temporal variations of the melt sources may be interpreted in terms of plate tectonics. 3.Establish a precise relationship between the eruption dynamics and the highest environmental stress leading to the biotic response: end-Triassic mass extinction and lower Toarcian anoxic event, respectively (high-precision data for marine environmental and biotic crises established in former projects). These data will discriminate between models of pre-volcanic peak extinction versus maximum environmental stress and extinction during the peak volcanic activity.4.Calibrate the E23r magnetic interval at at the Triassic-Jurassic boundary, and the "van Zjil" magnetic reversal in the Toarcian at a ±50-100 ka level, used for global correlation of terrestrial sedimentary and volcanic deposits.5.Contribute to further quantify the apparent 0.8% offset between 40Ar/39Ar and 206Pb/238U dates.
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