From paradise to mass extinction: correlating and comparing low and high latitude basins during the greatest Permian extinction events and subsequent faunal recoveries.

Informations projet

ExtinctRecov

N° de convention de subvention: 101060666

DOI

10.3030/101060666

Projet clôturé

Date de signature de la CE 20 Juin 2022

Date de début 1 Octobre 2022

Date de fin 31 Mai 2025

Financé au titre de

• Marie Skłodowska-Curie Actions (MSCA)

Coût total

Aucune donnée

Contribution de l’UE

€ 184 933,87

Coordonné par

Institut Català de Paleontologia Fundacio Privada
Spain

Periodic Reporting for period 1 - ExtinctRecov (From paradise to mass extinction: correlating and comparing low and high latitude basins during the greatest Permian extinction events and subsequent faunal recoveries.)

Période du rapport: 2022-10-01 au 2025-05-31

Résumé du contexte et des objectifs généraux du projet

Drastic global climate change during the Permian resulted in two of the greatest mass extinction events of all time, one around 260 Ma ago and the other around 252 Ma ago. Arguably the best record of these events on land is preserved in the main Karoo Basin of South Africa, which was situated in higher latitudes (~60° S) at those times. Because of the relatively poorer fossil record from lower (0-15°) palaeolatitudes, latitudinal differences in faunal assemblages, and lack of precise radiometric dates, global applicability of extinction and faunal recovery patterns observed in the MKB has long remained elusive; we simply lacked the necessary data. As such, stratigraphic correlations between basins are tenuous. Moreover, it is not known whether the terrestrial expression of the two greatest mass extinction events of the Permian, and subsequent ecosystem recovery, are preserved in western Europe.

Palaeontological and geological work undertaken in the past two decades have highlighted the presence of long continental successions ranging from the late Carboniferous to the Middle Triassic from lower palaeolatitudes in several European (France, Germany, Italy, Spain, Scotland) and north African (Morocco, Niger) basins. Most importantly, these have yielded a diversity of vertebrate and invertebrate body and trace fossils, which provide valuable new insights into life at lower palaeolatitudes during the Permian. Drawing on the geological, geochronological, and palaeontological advances and work undertaken during the past two decades in the Pyrenees and Lodéve basins (Spain and France) and the main Karoo Basin (South Africa), supplemented by new data collected during fieldwork, ExtinctRecov aims to, for the first time, combine palaeontological, sedimentological, stratigraphical and geochronological data to correlate and compare the Permian-Triassic Spanish and French basins and the main Karoo Basin, and provide valuable new insights into life at lower palaeolatitudes during the Permian and Triassic.

Building upon the results of previous studies and expanding to new theoretical and methodological questions, the project aims to fill the gap of two critical aspects:

1. Correlation of middle-to-late Permian deposits from the Pyrenees basins, Spain and nearby French basins, with coeval deposits from higher latitudes (main Karoo Basin).

2. Low-palaeolatitude Permian tetrapod assemblages and their surrounding environments, in association with climatic changes, and how they changed through time.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

The researcher participated in ten fieldwork campaigns targeting Permian-Triassic rocks in Spain (7) and France (3). The purpose of the fieldwork was to prospect for and excavate palaeontological samples, collect geological samples for detrital zircon age dating and petrographic analysis, and to measure stratigraphic sections so that the samples could be accurately placed in stratigraphic context and to better understand the depositional environment. The fieldwork has been highly productive, with hundreds of new (body and trace) fossil specimens discovered and collected. These include several new vertebrate and insect taxa, or the first occurrence from Spain. More than 28 rock samples for detrital zircon and petrographic analysis were collected from the Permo-Triassic succession in the Catalan Pyrenees.

U-Pb age dating of detrital zircons using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was done for the first time for samples from the Catalan Pyrenees Basin. A total of 1155 grains from 19 samples were analysed, with a further five samples being processed but not providing enough zircon grains for analysis. Although most of the obtained ages are older than the expected age of deposition - but coincide with ages obtained from volcanic rocks stratigraphically lower down in the succession and reflect reworking of older rocks - the youngest populations of grains allow for a maximum depositional age to be estimated for the host rocks. A middle Permian age for the lower part of the upper Upper Red Unit is supported by the obtained ages of c. 277.5 Ma and c. 265.4 Ma from single zircon grains. Two grains from near the inferred Permo-Triassic Boundary at one locality gave an age of c. 256 Ma, which supports the presence of late Permian rocks at this locality. It is not possible to provide a constraint on the depositional age of the Triassic Bundsandstein facies because all the obtained U-Pb ages are older even than the ages obtained from the rocks of the underlying Upper Red Unit.

Databases of fossil specimens, based primarily on collections catalogues and supplemented with the literature, has been compiled for the main Karoo Basin, South Africa, and for the Permian and Triassic of the Cadí subbasin in the Catalan Pyrenees and the Montseny subbasin in the Catalan Coastal Ranges. A list of fossil taxa from the Lodéve Basin, France, has been compiled from the literature, and the researcher is collaborating with other researchers who have compiled a database of the fossils from the basin.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

Some of the most poignant results from the project include:

1) First radiometric ages from detrital zircons from Permian rocks of the Catalan Pyrenees. These allow the depositional age of the Upper Red Unit in the Cadí subbasin to be constrained to the middle to upper permian (c. 265 - 256 Ma ago). In conjunction with newly obtained palaeomagnetic data from the same section, and recently published U-Pb ages from other basins, these ages allow for better correlation with the chronostratigraphic time scale and with other basins. Furthermore, the spectrum of detrital zircon ages obtained can be used in future studies to provide valuable insights into the basin development and depositional history of the studied rock units.

2) The discovery of numerous new fossil specimens and localities, including the first identifiable vertebrate fossil cranial material from mainland Spain, which could represent some of the earliest members of the clade therapsida (the group that includes mammals) yet discovered. These fossils help fill a critical gap in the fossil record and have the potential to fundamentally change our understanding of life on Earth during the early to middle Permian, particularly with regards to therapsid evolution. Several of the specimens are being prepared for description and are the subject of ongoing work. Newly discovered localities will be targeted during future prospecting and excavation campaigns.