Conference Agenda

The causes of mass extinctions throughout Earth’s history have long been debated, particularly regarding the relative roles of large asteroid impacts and large igneous province (LIP) volcanism. For the end-Cretaceous mass extinction, the two main candidates are the Chicxulub impact and the Deccan Traps volcanic eruptions. While the impact hypothesis is widely accepted, the precise timing and environmental impact of the Deccan eruptions have been less clear. U-Pb zircon dating now indicates that ~80% of the Deccan basalts erupted during magnetic chron C29r, starting ~250,000 years before the Cretaceous-Paleogene (KPg) boundary and continuing into the early Paleocene, suggesting a causal link. Mercury (Hg) has often been used as a volcanic proxy in marine sediments, but its reliability is limited due to post-depositional alteration and inconsistent Hg/TOC ratios. Tellurium (Te), when normalized to conservative elements like thorium (Th), may offer a more robust volcanic tracer. This study presents a high-resolution geochemical analysis of Hg and Te across several marine sections from diverse depositional settings in Europe, North Africa, the Middle East, and India. Results show a dramatic increase (over two orders of magnitude) in both Hg and Te concentrations during the final 100 kyr of the Maastrichtian, extending into the early Danian (P1a). These peaks align with major Deccan eruption pulses and support the view that volcanism played a critical role in preconditioning global ecosystems through CO₂ and SO₂ emissions, ocean acidification, and warming—thereby exacerbating the ecological collapse triggered at the KPg boundary.

The Southeast Anatolian Basin, a key petroleum reservoir region in Türkiye, hosts critical Upper Cenomanian–Lower Turonian carbonate sequences in the İnişdere area. This study integrates biostratigraphic and geochemical analyses of neritic-hemipelagic Cenomanian-Turonian boundary interval (CTBI) strata to refine chronostratigraphic correlations. A notable δ¹³C excursion in the İnişdere section coincides with rising Mn/Ca and declining Ce/Ca ratios, reflecting enhanced organic carbon burial during the Oceanic Anoxic Event 2 (OAE2), linked to mass extinctions. δ¹⁸O) reveal paleoceanographic shifts in water column dynamics and sediment-water interface conditions, suggesting suboxic-to-anoxic transitions. Cross-plots of δ¹³C, δ¹⁸O, and rare earth element (REE) indicate minimal diagenetic alteration. Stratigraphic analyses—encompassing major/trace elements, REE, TOC (0.85–2.92 wt%), stable isotopes (δ¹³C, δ¹⁸O), and ⁸⁷Sr/⁸⁶Sr ratios—highlight lower Turonian organic-rich limestones formed under outer ramp anoxia. Elevated redox-sensitive elements (U, Th, V, Co, As, Cr) in black limestones underscore anoxic conditions favoring organic preservation. These geochemical trends align OAE2 with platform drowning during the CTBI. The chemostratigraphic record correlates with regional Neotethys paleoenvironmental shifts, emphasizing the basin’s role in global carbon cycle perturbations. This multi-proxy approach clarifies the interplay between anoxia and platform drowning during OAE2.

Deposited during the Late Cretaceous in the southern part of the Western Interior Seaway and the northeastern portion of the Mexican Interior Basin, the Eagle Ford Formation is one of the most prolific hydrocarbon source rocks in the world due to its high organic matter content. Recently, the IRME-1 core from a drill site in the Sabinas basin recovered a complete succession of this unit. This study aims to analyze the organic matter in this core to evaluate its origin and thermal maturity. The analytical techniques employed, which are typically applied independently, were combined in a multiproxy approach that included petrographic (palynofacies analysis, spore coloration index-SCI, vitrinite equivalent reflectance-%Ro_Eq) and geochemical (Rock-Eval pyrolysis, biomarkers) proxies. The terrigenous-to-aquatic ratio (TAR) and odd-even preference (OEP) suggest that the organic matter is predominantly of marine origin. These results are consistent with the hydrogen and oxygen indexes, and palynofacies analysis, which classify the kerogen as type II-III (predominance of Amorphous Organic Matter, accompanied by a moderate content of degraded non-biostructured phytoclasts and a very low proportion of opaque phytoclasts). As for the thermal maturity indicators, significant variability is observed. The Rock-Eval Tmax parameter (362–449°C) suggests an immature to early mature stage. However, the remaining indicators (%RoEq: 1.40-1.83; %VRm: 1.42–1.77, calculated as 0.2633×LnMDR; SCI: 8–10), consistently point to advanced thermal maturity (overmature). This variability highlights the importance of integrated studies that compare multiple techniques, which enable a more accurate characterization of the organic matter.

The Greensand at Nasiłów (Poland) is a unique glauconite-quartz-sand unit topped by a phosphatic layer. It represents the most unusual sedimentological unit across the Cretaceous–Paleogene (K–Pg) boundary in the region. This c. 40 cm-thick bed, enclosed between Maastrichtian and Danian carbonates, contains reworked micro- and macrofossils, including belemnite rostra, other molluscs' shells and spongy phosphatic fragments. New foraminiferal and dinoflagellate cyst biostratigraphic data, in addition to paleomagnetic data, show that the boundary interval at Nasiłów is nearly complete.

Sedimentologically, Greensand displays an erosive base, chaotic grading, and exotic quartz pebbles up to 3 cm in size. Other sedimentological and taphonomic features, such as the orientation of belemnite rostra and other shells, in addition to specific preservation of certain fossils, when combined, cannot be explained by ordinary sedimentary processes.

All these characteristics indicate a high-energy environment and that the Greensand might represent a tsunami deposit triggered by the Chicxulub impact at the K-Pg boundary. This extraordinary tsunami likely crossed the Atlantic Ocean, reworked the uppermost Maastrichtian sediments in the epicontinental European sea and deposited them as clastic remixed deposits represented by Greensand in Nasiłów.

This study demonstrates that impact-generated tsunamis might have played an important role in shaping K–Pg sections around the Atlantic and likely beyond. The widespread hiatal character of many K–Pg sites, including deep-ocean records, may thus be attributed to this mega-tsunami. Consequently, tsunami-related processes should be considered in future sedimentological interpretations of the K–Pg boundary worldwide, from shallow marine to abyssal environments.

The El Doctor Carbonate Platform was an isolated bank that developed in central Mexico during the Albian–Cenomanian. This study documents environmental changes associated with the drowning of this carbonate system, based on petrographic, mineralogical, and geochemical analyses from a stratigraphic section recording the transition from thick-bedded, shallow-water limestone to thin-bedded marly limestone and mudstone. The section was age constrained by foraminiferal biostratigraphy to the late Cenomanian-early Turonian. Pre-drowning facies consist of bioturbated mudstone and wackestone with mollusk fragments and miliolids, commonly exhibiting fenestral fabrics, indicative of deposition in a lagoonal-peritidal environment. Drowning facies are dominated by microbialites and intraclastic packstone with echinoderm fragments, reflecting deposition under environmentally stressed marine conditions. Post-drowning facies comprise laminated wackestone and packstone, relatively rich in organic matter and containing calcispheres, radiolarians, and planktonic foraminifera. They were accumulated in a pelagic deep-water basinal setting. The drowning of the platform was driven by an increased influx of terrigenous material, triggered by both the switch towards more warm and humid climate conditions and the effects of the Laramide orogeny in central Mexico. Additionally, a change to more eutrophic surface waters and oxygen-depleted bottom conditions contributed to the platform demise. These processes occurred during the Oceanic Anoxic Event 2 (OAE 2), as evidenced by a pronounced positive carbon isotope excursion throughout the section.

The territory of Georgia, as well as the entire Caucasus region, during the Cretaceous period, was an area of intense volcanic activity parallel to sedimentation processes. During the Late Cretaceous, the southern slope of the Greater Caucasus was the northern edge of Tethys, and volcanic activity with varying intensity covered almost all geological units in Georgia and occurred under conditions of alternating stretching and compression of the Earth’s crust. During the Mesozoic history of the Western Georgia, three pulses of volcanic activity are registered, appearing in the Bajocian, Tithonian–Kimmeridgian, and Late Cretaceous stages, respectively. The formation of a thick volcanic–sedimentary sequence known as the „Mtavari“ formation is related to the Turonian–Santonian stage. This formation is composed by the covers and pyroclastic masses of alkaline basalts, trachyandesite, trachytes, and phonolites alternating with the units of limestones and marls. It should also be noted that the Middle Turonian-Coniacian deposits are represented by pink and red limestones and marbles (the red color is due to the presence of hematite pigment, which indicates oxidizing conditions during early diagenesis in a relatively deep-sea marine environment). An improved method of washing carbonate limestones has yielded well-preserved foraminifera shells. Based on planktonic foraminifera, the following complexes were identified: Marginotruncana schneegansi/pseudolinneiana, Marginotruncana coronata, Marginotruncana sigali - M. renzi, Concavatotruncana concavata, Contusotruncana fornicata, Globotruncana arca, Globotruncana ventricosa. Based on planktonic foraminifera, the following complexes were identified: Marginotruncana schneegans-pseudo linneana, Marginotruncana coronata, Marginotruncana sigali- Marginotruncana renzi, Concavatotruncana concavata, Contusotruncana fornicata, Globotruncana arca, Globotruncana ventricosa.