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