The Permian–Triassic transition in Türkiye: New insights and 3D outcrop models for accessible, reproducible and sustainable fieldwork

<p>About 252 million years ago, near the end of the Permian, the Earth experienced its most dramatic mass extinction, caused by magmatic intrusions and volcanic eruptions associated with the Siberian Traps Large Igneous Province. This led to catastrophic global climatic changes, impacts of which lasted well into the Early Triassic.</p><p>Here, we summarise the results gathered from the study of sedimentary successions spread across the Barents Shelf that recorded the End Permian Mass Extinction (EPME) and its aftermaths across the Permian-Triassic boundary. Data and samples were collected from the Festningen section in western Spitsbergen; the DD-1 core and the associated river section in Deltadalen, central Spitsbergen; a core (7933/4-U-3) drilled by the Norwegian Petroleum Directorate offshore Kvitøya in northern Svalbard; and a core (7130/4-1; production licence 586) recovered from the Finnmark Platform in the Barents Sea. A series of state-of-the-art analyses were conducted on the collected material, including detailed facies analysis, organic and C-isotope geochemistry, mercury content, geochronology, high resolution XRF core scanning, petrography, ichnology, and palaeontology. Analyses were, where relevant, tied to the outcrops using digital outcrop models.</p><p>Traditionally, the Permian-Triassic boundary in Svalbard (and across the High Arctic regions) was placed at the marked and rapid facies change at the top of the siliceous mudstones and spiculites of the Kapp Starostin Formation, which are overlain by soft, non-siliceous mudstones and siltstones of the Vardebukta and Vikinghøgda formations. This abrupt facies change, which also marks the collapse of sponges, occurs across a few centimetres. Given that the non-siliceous mudstones were definitely of Early Triassic age, based on ammonoid biostratigraphy, this lithostratigraphic boundary was believed to represent a lacuna or a hiatus of several million years, with the uppermost Permian strata absent from the sedimentary record.</p><p>The base of the Triassic, however, is not defined by ammonoid biostratigraphy but by the conodont<em> Hindeodus parvus</em>, which was recently reported to occur a few meters above the lithostratigraphic boundary in the Deltadalen section. This means that the lithostratigraphic boundary is of Permian age. Additionally, our new data show that sedimentation was continuous across this lithostratigraphic boundary, corresponding to major environmental changes, potentially associated with a reorganisation of the basin(s) physiography.</p><p>Furthermore, the 6-8 ‰ δ<sup>13</sup>C<sub>org</sub> negative excursion associated with the EPME falls between the lithostratigraphic and the Permian-Triassic boundary at all measured sections. These negative carbon isotope excursions occur in intervals with numerous tephra layers, the lowest of which has been dated at 252.13 ± 0.62 Ma, potentially connecting the recorded changes to the Siberian Traps. The EPME is also corroborated by the very abrupt decline of trace fossil abundance and diversity, as anoxia extended from proximal and shallow water to deeper settings. Geochemical and ichnological data support the existence of multiple anoxic pulses, separated by very brief periods of enhanced oxygen levels. It took ca. 150 Kyr for life to recover after the EPME, based on sedimentation rate calculations. Data also suggest that the hinterland of the basin experienced a shift towards more arid climatic conditions and increased eutrophication.</p>

Carbon-Sulfur isotope and major and trace element variations across the Permian–Triassic boundary on a shallow platform setting (Xiejiacao, South China)

The identification of the factors triggering continental environmental changes at the Permian–Triassic transition is of general interest as they allow a better understanding of the most controversial mass extinction of the Phanerozoic. This study investigates the environmental response to external forcings on continental successions at the south‐east‐margin of the Central European Basin System in Germany. Studies from this area are scarce, and its evolution is poorly understood. This work integrates high‐resolution core‐logging and quantitative sedimentary petrography of Middle Permian–Early Triassic successions recovered from the wells Obernsees‐1 and Lindau‐1. The sedimentological investigation reveals major vertical variations in the depositional settings marked by changes in grain‐size trends and facies associations: (i) the progradation of mass flow/fluvial fans over sandflat environments denotes the Guadalupian–Lopingian; (ii) sabkha to shallow‐marine conditions occur during the uppermost Permian; (iii) the onset of braided fluvial sequences marks the Permian–Triassic boundary; (iv) changes in fluvial style, reflecting increased river sinuosity, and aeolian deposition characterize the remaining Triassic. Environmental changes are accentuated by variations in sediment composition. Proximal deposits (for example, alluvial fan) are lithic arkoses, while more distal associations reveal arkosic composition. Detrital modes point to: (i) a high‐grade metamorphic source feeding the drainage of Lindau‐1 (metamorphic index, MI 441–500); and (ii) a mixed low‐grade and high‐grade metamorphic source (MI 277–395) feeding the Permian of Obernsees‐1, passing upward to high‐grade metamorphic (MI 441–500) and subordinate granitoid sources. Compositional signatures and environmental changes suggest distinct drainage evolutions regulated by upstream climate and tectonic controls. The higher plutonic clast content coeval to the onset of fluvial sedimentation and coarse‐grained influxes reflects local tectonic perturbations attributed to the Early Triassic reactivation of Variscan faults. The evidence of perennial fluvial systems during the lowermost Triassic reflects wetter climate conditions in the upstream catchment area, which contradicts the common view of increased aridity at the Permian–Triassic boundary.

Spatiotemporal disparity of volcanogenic mercury records in the southwestern Neo-Tethys Ocean during the Permian–Triassic transition

A Permian-Triassic (P-Tr) boundary section of continuous carbonate facies, which well recorded the biotic and environmental processes through the great P-Tr transition in the shallow non-microbialite carbonate facies, has been studied in Yangou, Leping County, Jiangxi Province. The P-Tr sequence is well correlated with the Meishan section according to the conodont biostratigraphy and the excursion of carbon isotopes. A series of high-resolution thin-sections from the P-Tr boundary carbonate rocks at the Yangou section are studied to explore the interrelation between environmental change and biological evolution during the transitional time. Six microfacies have been identified based upon the observation of the thin-sections under a microscope on the grains and matrix and their interrelation. Combined with the data of fossils and carbon isotopes, Microfacies 4 (MF-4), coated-grain-bearing foraminifer oolitic sparitic limestone, and Microfacies 6 (MF-6), dark shelly micritic limestone, should be the different responses to the two episodes of mass extinction and environmental events that can be correlated throughout South China and even over the world. The oolitic limestone of MF-4 is the first finding from the latest Permian strata in South China and it might be a proxy of an unusual environmental condition of high pCO2, low sulfate concentration and of microbial blooming in the aftermath of the latest Permian mass extinction. The micritic limestone of MF-6 containing rich micro-gastropods and ostracods probably represents the blooming event of disaster taxa in the earliest Triassic environment. The microfacies analysis at the Yangou section can well reveal the episodic process of the biological evolution and environmental change in the shallow non-microbialite carbonate facies throughout the great P-Tr transition, thus the Yangou section becomes an important complement to the Meishan section.

Biostratigraphic correlation and mass extinction during the Permian-Triassic transition in terrestrial-marine siliciclastic settings of South China

Continental records of organic carbon isotopic composition (δ13Corg), weathering, paleoclimate and wildfire linked to the End-Permian Mass Extinction

Research on the Permian-Triassic boundary (PTB) along the northern margins of Pangaea (exposed today in the Arctic region) has been heavily reliant on field observations, where data resolution was consequently determined by outcrop condition and accessibility. Core drilling in central Spitsbergen allowed for a near-complete recovery of two ~90 m cores through the PTB. Analyses of the core and nearby outcrops include stratigraphic logging and sampling, XRF scanning, petrography, biostratigraphy, isotope geochemistry, and geochronology. The First Appearance Datum (FAD) of H. parvus in Svalbard places the base of the Triassic ca. 4 m above the base of the Vikinghøgda Formation, and ca. 2.50 m above the End-Permian Mass Extinction (EPME) and its associated sharp negative δ13C. The PTB therefore falls within the Reduviasporonites chalastus Assemblage Zone in Svalbard. Precise U-Pb TIMS dating of two zircon crystals in a tephra layer just above the first documented Hindeodus parvus in Svalbard gives an age of 252.13 ± 0.62 Ma. High-resolution palaeoenvironmental proxies, including Si/kcps (kilo counts per second), Zr/Rb, K/Ti, Fe/K, and V/Cr, indicate a transition towards a more arid climate in the earliest Triassic, contemporaneous with prolonged bottom-water dysoxic/anoxic conditions, following an increase in volcanic activity in the Late Permian. Statistical analysis of Zr/Rb, K/Ti and V/Cr elemental ratios suggests that the system was impacted by long-eccentricity (400 kyr) cyclicity. The δ13C excursion in organic carbon (δ13Corg) record signals a large negative carbon isotope excursion (CIE) associated with the mass extinction event, but also records a second, smaller negative CIE ca. 22 m above this interval. This younger δ13Corg excursion correlates to similar CIEs in the Dienerian (late Induan) records of other sections, notably in the Tethys Ocean, which have been interpreted as recording a small biotic crisis during the post-extinction recovery. Evidence of this negative CIE in Spitsbergen suggests that the Dienerian crisis may have been global in extent. The negative δ13Corg values are associated with evidence for dysoxia or anoxia in the core, and the occurrence of tephra layers in the same interval suggests a possible connection between the Dienerian crisis and a discrete episode of volcanic activity.

<p>The onset of the Siberian Traps Large Igneous Province at the Permian–Triassic transition significantly affected climate and depositional environments across the world. Known long term consequences of this event are (I) global warming, (II) increased continental weathering, (III) oceanic stagnation and acidification and (IV) mass extinction. These effects have the potential to strongly alter signals from source-to-sink systems in terms of petrography, sediment volumes and geochemistry. On the Finnmark Platform, a shift in provenance from a southern source to an eastern source during the middle Triassic is known. However, the impact of the environmental changes at the Permian-Triassic transition have so far not been investigated. The Barents Sea Basin contains a continuous record of sediments deposited before, during and after the Permian-Triassic event. The interval is present in several exploration wells, which show the transition in individual depositional environments. Therefore, it serves as an excellent area to investigate the response of source-to-sink systems to such extreme climatic changes.</p><p>The goal of this project is to investigate how the Triassic climatic changes were expressed in source-to-sink systems, mainly using techniques such as provenance, facies analysis, petrography, and sediment volumes. Herein we present preliminary provenance and petrography results mainly from Induan-aged sandstones and clasts from the Havert Formation. On the Finnmark Platform, upper Permian spiculate mudstones, limestones, and sparse sandstones are overlain by Lower Triassic mudstones and interbedded sandstones, which deposited as turbidites and prograding deltas. In order to determine how the signal from the catchment changed in relation to the great climatic changes, it is of high importance to examine changes within provenance and sediment volumes across the Permian-Triassic transition.</p>

The Lung Cam expanded stratigraphic succession in Vietnam is correlated herein to the Meishan D section in China, the GSSP for the Permian–Triassic boundary. The first appearance datum of the conodontHindeodus parvusat Meishan defines the Permian–Triassic boundary, and using published graphic correlation, the Permian–Triassic boundary level has been projected into the Lung Cam section. Using time-series analysis of magnetic susceptibility (χ) data, it is determined thatH. parvusarrived at Lung Cam ∼18 kyr before the Permian–Triassic boundary. Data indicate that the Lung Cam section is expanded by ∼90 % relative to the GSSP section at Meishan. Given the expanded Lung Cam section, it is possible to resolve the timing of significant events during the Permian–Triassic transition with high precision. These events include major stepped extinctions, beginning at ∼135 kyr and ending at ∼110 kyr below the Permian–Triassic boundary, with a duration of ∼25 kyr, followed by deposition of Lung Cam ash Bed + 13, which is equivalent to Siberian Traps volcanism is graphically correlated to a precession Time-series model, placing onset of this major volcanic event at ~242 kyr before the PTB. The Meishan Beds 25 and 26, at ∼100 kyr before the Permian–Triassic boundary. In addition, the elemental geochemical, carbon and oxygen isotope stratigraphy, and magnetostratigraphy susceptibility datasets from Lung Cam allow good correlation to other Permian–Triassic boundary succession. These datasets are helpful when the conodont biostratigraphy is poorly known in sections with problems such as lithofacies variability, or is undefined, owing possibly to lithofacies exclusions, anoxia or for other reasons. The Lung Pu Permian–Triassic boundary section, ∼45 km from Lung Cam, is used to test these problems.

Millennial-scale sedimentary evolution of carbonate platforms during the Permian–Triassic boundary hyperthermal event

Turbulent paleoenvironment linked to astronomical forcing during the Permian–Triassic transition

The Permian–Triassic extinction was the largest Phanerozoic mass extinction event, yet its ultimate causes remain unresolved. Ocean redox conditions, global warming, and carbon cycle perturbations owing to massive volcanism and their inter-relationships are keys to resolve the origins of this event. We here assess such relationships using a method to obtain an instantaneous stratigraphic response from high-resolution (millennial-scale) records of carbonate-δ13C and pyrite framboid size distributions across the Permian–Triassic boundary (PTB) at Meishan, China. We report two gradual long-term negative δ13C shifts before and after the PTB. Late Permian ocean redox conditions varied through three successive oxic–dysoxic, dysoxic–euxinic, and high-frequency euxinic stages. Oxic and high-frequency euxinic events occurred in the early Griesbachian and middle Griesbachian, respectively. The short-term euxinia events were not associated with the negative δ13C excursions. Siberian volcanism could have produced large light-carbon inputs, global warming, and low-oxygen conditions at intermediate ocean depths, but it may not directly drive high-frequency euxinia across the PTB. Long-term dysoxia and occasional euxinia well before the PTB stressed mobile macroorganisms and caused gradual extinction before the major extinction event. High-frequency latest Permian euxinia reduced overall biotic adaptability, and caused the initial rapid mass extinction. Increasing temperatures and other deleterious environment factors then reinforced the extinction process. Oxic conditions contributed to biotic recovery immediately after the mass extinction in the early Griesbachian. Further millennial-scale dysoxic/euxinic alternations in the middle Griesbachian would have prolonged Early Triassic biotic recovery.

ABSTRACTThe strata encompassing the Permian–Triassic boundary interval capture a pivotal period in Earth's history, with significant changes in Phanerozoic Earth system dynamics, culminating in a severe mass extinction. In carbonate platforms, this boundary is marked by a shift from skeletal to microbial carbonate production. Whereas extensive research has focused on the End‐Permian Mass Extinction in open‐marine shelf environments, the transition within inner platform facies remains underexplored due to limited dating options and pervasive dolomitization. This study examines the Permian–Triassic boundary interval at the continuous dolostone, Brušane‐Sy section, in the External Dinarides (Croatia), that retains much of its original fabric. High‐resolution petrography, biostratigraphy and chemostratigraphy (δ13Ccarb and δ13Corg) were utilized to detail sedimentary responses across the boundary. The Upper Permian fine‐crystalline dolostone features well‐preserved cryptomicrobial/bioclastic, peritidal microfacies with calcareous algae and foraminifera. In contrast, the Lower Triassic dolostone, shows a transition to a medium‐crystalline, fabric‐destructive dolostone texture. The transition from fabric‐retentive Permian to fabric‐destructive Triassic dolostone is attributed to two dolomitization processes: (i) Late Permian transgression facilitating aragonite/high Mg‐calcite deposition, later transforming neomorphically into fabric‐retentive dolostone texture due to abundant precursor dolomite nuclei; and (ii) dispersed Early Triassic primary dolomite precipitation later stabilized during shallow burial with decaying microbial mats serving as loci for crystal growth but decreased nucleation. This shift is recorded by a minimal negative δ13Ccarb excursion (≤0.7‰) and a more pronounced shift in Δ13C (δ13Ccarb – δ13Corg; ca 4.6‰). Contrasting with typical open‐marine Permian–Triassic boundary excursions, such isotopic features reflect the localized shift in primary production to photoautotrophy (algae and cyanobacteria) and early dolomitization in the presence of seawater‐derived dissolved inorganic carbon. Understanding these sedimentary and diagenetic dynamics provides crucial insights into environmental changes and biogeochemical cycles affecting Permian–Triassic boundary dolomitization, offering a comprehensive view of the End‐Permian Mass Extinction across a wider range of shallow marine carbonate dominated depositional environments.

Sulfur isotope profiles in the pelagic Panthalassic deep sea during the Permian–Triassic transition