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Temporal coupling of environmental change, volcanism and evolution in the geological past through high-precision geochronology

English title Temporal coupling of environmental change, volcanism and evolution in the geological past through high-precision geochronology
Applicant Schaltegger Urs
Number 182007
Funding scheme Project funding (Div. I-III)
Research institution Département des sciences de la Terre Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Geochronology
Start/End 01.01.2019 - 30.09.2022
Approved amount 1'140'102.00
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Keywords (11)

flood basalts; Large Igneous Province; U-Pb geochronology; atmospheric chemistry; Karoo volcanic province; South Africa; mass extinction; 40Ar-39Ar geochronology; timescale calibration; China; Triassic

Lay Summary (German)

Lead
Welche Mechanismen koppeln geologische Prozesse im Erdinnern und an der Erdoberfläche mit dem Klima und der Evolution des Lebens? Diese Fallstudie untersucht die vulkanische Aktivität der Karoo Vulkaniprovinz in Südafrika/Lesotho (eine sogenante "Large Igneous Province"), welche vor 183 Millionen Jahre das Erdklima dramatisch veränderte. Teile der weltweiten Ozeane erwärmten sich so stark, dass sie keinen gelösten Sauerstoff mehr enthielten. Diese anoxischen Bedingungen führte zu einer Periode starker Reduktion der Biodiversität.
Lay summary

Mit U-Pb und Ar-Ar Altersbestimungen an Mineralien von vulkanischen und intrusiven Gesteinen werden wir versuchen die Dauer und die Intensität des Vulkanismus zu bestimmen. Falls sich Perioden erhöhter magmatischer Aktivität erekennen lassen, kann man diese mit periodischen Klimaänderungen korrelieren, welche sich aus zyklischen Veränderungen der Biodiversität ableiten lassen. Diese wurden an marinen Lebwesen rekonstruiert (z.B. Ammoniten und Foraminiferen).

Ein weiterer Forschingsschwerpunkt befasst sich mit der Rekonstruktion der Gase, welcher dieser Vulkanismus in die Atmosphäre einbrachte. Vor allem interessieren uns klimarelevante Gase: CO2 ist das hauptsächliche Treibhausgas, welches unser aktuelles Klima verändert, SO2 ist ein Gas, welches in der Atmosphäre Aerosole bildet und die Sonneneinstrahlung reduziert. Diese Daten werden wir dazu benutzen um die Rolle dieser magmatischen Gase zu evaluieren und um sie mit den sogenannten "thermogenen" Gasen zu vergleichen: Gase welche durch die Metamorphose der Sedimente freigesetzt werden, wenn sie von 1200 Grad heissen Schmelzen intrudiert werden.

Vielleicht kann dieses Projekt Antworten finden auf die Frage: wieso hat die Aktivität einer grossen Vulkanprovinz wie zum Beispiel diejenige der Siberian Traps vor 252 Millionen Jahren zum grössten Massensterben in der Erdgeschichte geführt, während die Karoo Provinz bei weitem nicht denselben Effekt hatte?

Direct link to Lay Summary Last update: 28.09.2018

Responsible applicant and co-applicants

Employees

Project partner

Publications

Publication
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)
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.
Pervasive Hydrothermal Events Associated with Large Igneous Provinces Documented by the Columbia River Basaltic Province
Bindeman I. N, Greber N. D., Melnik O. E., Artyomova A. S., Utkin I. S., Karlstrom L., Colón D. P. (2020), Pervasive Hydrothermal Events Associated with Large Igneous Provinces Documented by the Columbia River Basaltic Province, in Scientific Reports, 10(1), 10206-10206.
New high precision U-Pb ages and Hf isotope data from the Karoo large igneous province; implications for pulsed magmatism and early Toarcian environmental perturbations
Greber Nicolas D., Davies Joshua H.F.L., Gaynor Sean P., Jourdan Fred, Bertrand Hervé, Schaltegger Urs (2020), New high precision U-Pb ages and Hf isotope data from the Karoo large igneous province; implications for pulsed magmatism and early Toarcian environmental perturbations, in Results in Geochemistry, 1, 100005-100005.
Dynamics of the Largest Carbon Isotope Excursion During the Early Triassic Biotic Recovery
Widmann Philipp, Bucher Hugo, Leu Marc, Vennemann Torsten, Bagherpour Borhan, Schneebeli-Hermann Elke, Goudemand Nicolas, Schaltegger Urs (2020), Dynamics of the Largest Carbon Isotope Excursion During the Early Triassic Biotic Recovery, in Frontiers in Earth Science, 8, 196.
The chemistry of fine-grained terrigenous sediments reveals a chemically evolved Paleoarchean emerged crust
Greber Nicolas D., Dauphas Nicolas (2019), The chemistry of fine-grained terrigenous sediments reveals a chemically evolved Paleoarchean emerged crust, in Geochimica et Cosmochimica Acta, 255, 247-264.

Awards

Title Year
Robert Wilhelm Bunsen medal of European Geosciences Union 2021

Associated projects

Number Title Start Funding scheme
169086 Direct determination of early Earth's orbital parameters through high-precision age determination of sedimentary cycles in Archean and Proterozoic sedimentary deposits 01.01.2017 Project funding (Div. I-III)
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 (Div. I-III)
177026 Re-equiping the noble gas laboratory to perform state of the art science, University of Geneva 01.03.2018 R'EQUIP
156424 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 01.12.2014 Project funding (Div. I-III)
163984 A new termal ionization mass spectrometer for high-precision U-Pb geochronology 01.12.2015 R'EQUIP

Abstract

This proposal seeks funding to study the timing of processes at the interface of Earth sub-systems, e.g., the timing of massive volcanic activity in Large Igneous Provinces (such as the Karoo Large Igneous Province of S. Africa) and the feedback from the biosphere, or, more specifically, the effect of volcanic volatile degassing on the chemistry of the atmosphere and its impact on climate, environment and life. To reveal these feedbacks in deep geological time, we are relying on precise and accurate geochronology, mainly chemical abrasion, isotope-dilution, thermal ionisation mass spectrometry (CA-ID-TIMS) U-Pb dating techniques. Subproject 1 will study the total duration and the tempo of the Karoo Large Igneous Province (KLIP), and reconstruct the evolution of the different melt sources (lithosphere, asthenosphere, plume and crust) over time. With precise dates it will be possible to correlate pulses of magmatism with pulsed biotic and environmental crises in the marine sedimentary record of the Lower Jurassic. This research will be carried out by a post-doc (sills and dykes of the Karoo basin, S. Africa), and a PhD student (Drakensberg flood basalts in Lesotho).Subproject 2 will try to estimate the volumes of magmatic volatiles released by the KLIP magmas through analysis of concentrations and isotopic compositions of volatile elements in apatite from dated samples of subproject 1 (S, Cl, H). The post-doc will develop apatite sulphur and hydrogen isotope analysis as a novel geochemical tool for quantifying the volatile load of LIP magmas and look at changes of volatile composition and load over time.Subproject 3 represents the final stage of an ongoing PhD study, which will propose a Bayesian age model for the Early and Middle Triassic (Nanpanjiang basin, S. China) as a reference timeline for future studies, to link biostratigraphy, biogeochemical cycles and climate forcing in a period of massive climate variation.This is a large and ambitious research initiative that will touch fundamental topics, like (i) relating variations of the biosphere of marine sedimentary records to environmental change in the lower Jurassic and lower Triassic; (ii) defining the volumes of magmatic volatile release from LIPs compared to thermogenic (contact-metamorphic) volatiles and assessing the role of magmatic volatiles in climate forcing; (iii) understanding why the Karoo LIP did not lead to a mass extinction while others did; (iv) identifying environmental forcing through pulses of Karoo LIP volcanism as a cause for cyclic biodiversity changes in the lower Jurassic.
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