The Pannonian Basin in Central and Southeastern Europe is a huge landlocked basin delineated by Alpine-Carpathian-Dinarides chain. This extensional backarc basin originating by tectonic rifting at about 18 Ma, was successively flooded by the Central Paratethys Sea. The Slovenian Corridor along the Alpine-Dinarides junction enabled its communication with the Mediterranean Sea. Marine flooding along the southern margin of the Pannonian Basin - between the Styrian Basin in Austria and Velika Morava Basin in Serbia - is still poorly understood. While the conflicting biostratigraphic interpretations contribute to ongoing discussions on the timing and mode of this major environmental turnover, independent radiometric data are still rare. The present study contributes three new U-Pb zircon ages which are the very first such data on the Miocene marine transgression in northern Bosnia and Herzegovina. Datings from primary volcaniclastic deposits prove the middle Badenian age for marine transgression uniformly, with a 0.5 Ma eastwards-younging trend of its onset, dated at 14.6 Ma in Prnjavor Basin and at 14.1 Ma in the Tuzla Basin. This trend stays in line with the literature data suggesting a steady eastwards propagation of extension along the Pannonian Basin southern margin. Towards a better understanding of the interplay between tectonic and glacioeustatic forcing of the regional marine progression, a review of published stratigraphic data has been conducted, depicted correspondingly in four paleogeographic maps of similar to 1-Myr resolution. Building on these data, we bracket the initial gradual flooding interval to the late Burdigalian-early Serravallian (17 to 13.5 Ma) time interval, respectively, attaining up to 3.5 Myr overall duration in a step-wise manner. We infer fault growth and linkage as mechanisms controlling the hydrological pathways and thereby the direction of the transgression. This implies a transgression direction oblique to the main regional extensional direction. In some cases, local stress changes may lead to formation of sea pathways/gates opposite to the direction of extension. Although the tectonic phases were the main drivers in the creation of accommodation space, along the NE Dinarides, glacioeustasy driven by the global climate suspended the landward propagation of the coastline during sea-level low-stands at long obliquity nodes.

A striking difference along the Alpine Orogen is the style of collisional tectonics during the Oligo-Miocene, with the onset of escape tectonics in the Eastern Alps. The indentation of the Adriatic Plate into the Eastern Alpine Orogen resulted in the formation of conjugate dextral and sinistral strike-slip faults in the vicinity of the Tauern Window. Moreover, major changes occurred in the foreland of the Eastern and Southern Alps in the Early Miocene, with the cessation of the northern Alpine front propagation and the onset of thrusting along the Southern Alpine Front. In this study, we present new results from structural, stratigraphic and subsidence analyses of the eastern North Alpine Foreland Basin (NAFB).Our results show an initial phase of foreland sedimentation in the eastern NAFB between ca. 33-28 Ma, followed by a period of strong, tectonically driven subsidence between ca. 28-25 Ma, ending with a phase of erosion and formation of the basin-wide erosional unconformity, the Northern Slope Unconformity (NSU). During this time, the rift-related Mesozoic normal faults of the European platform were reactivated and then capped by the NSU. We interpret this phase as an increase in the flexure of the subducting European Plate under the growing Alpine Orogen. Between 25-19 Ma, the eastern NAFB remained in a deep-marine, underfilled state with a gentle increase in subsidence. A major shift took place around 19-17 Ma with tectonic uplift, ranging from 200 m (absolute minimum) to 1200 m depending on uncertainties on paleo-water depths, and rapid sedimentary infill of the basin. We discuss the possible causes for this major tectono-sedimentary shift in the eastern NAFB in relation to changes in collisional tectonics within the Eastern and Southern Alps, including a potential Early Miocene slab break-off event beneath the Eastern Alps.

Diatom-rich sediments exposed along the coastline of northern and central Chile are fundamental archives of coastal upwelling properties associated with the Humboldt Current System in the Neogene. One of the southernmost occurrences of Neogene diatom-rich sediments is known from the Tongoy Peninsula (30.3 degrees S). This study presents new bio- and magnetostratigraphic data from diatomaceous mudstones in the Quebrada Las Salinas, together with an assessment of the depositional environment. The results constrain the outcrop to the upper Tortonian to Messinian (c. 7.6-6.0 Ma). If the absence of Fragilariopsis miocenica is considered a true biostratigraphic signal, the range may be constrained to the uppermost Tortonian (c. 7.6-7.3 Ma). The comparison with previous studies suggests that Neogene diatom-rich deposits in the study area are highly diachronous within and between quebradas, extending from the Tortonian to the Pleistocene. Assemblages of siliceous microfossils indicate coastal upwelling in the Tongoy Palaeobay, increasing in intensity over the studied time interval. The intensification of coastal upwelling may have been the result of the coeval strengthening of the Antarctic Circumpolar Current and the Humboldt Current System.

Neogene diatom-rich deposits of north-central Chile represent fundamental archives for studying the dynamic relationship between sea surface temperatures and paleoclimatic fluctuations in the Atacama Desert. To ensure a reliable correlation between the (often discontinuous) marine and terrestrial archives, a well-calibrated stratigraphic framework is needed. In this sense, this study presents microfossil and sedimentological data from a c. 9m-thick diatomaceous mudstone deposit cropping out at the Quebrada Tiburón (27°42' S, 70°59' W, Bahía Inglesa Formation) for paleoenvironment investigations. Biostratigraphy, chemostratigraphy, and tephrochronometry correlated the diatomaceous mudstones with the upper Messinian and Zanclean (c. 6.1-3.6 Ma). To further improve the paleoceanographic interpretations and stratigraphic framework of the sequence, we also measured stable oxygen isotopes (δ18O) from two shallow infaunal benthic foraminifera species (Bulimina falconensis and Uvigerina striata/peregrina). However, the diatom-rich succession shows distinctive horizons of bioturbation, often associated with overlaying sandstones of variable thicknesses which are intercalated with the diatomaceous mudstones. These repetitive bioturbation cycles warrant caution when interpreting δ18O data, as they may imply potential hiatuses in sedimentation. At the same time, the observed cycles may provide the opportunity to establish a sequence stratigraphic framework for the deposition of the diatomaceous mudstones. Benthic foraminiferal assemblages from the mudstones indicate high export productivity and limited oxygen supply at the seafloor related to a coastal upwelling setting. The low-diversity fauna is mostly dominated by individuals < 150 μm of Bolivina granti/pacifica, Epistominella obesa, and Eubuliminella bassendorfensis. Across the Miocene/Pliocene boundary, the relative abundances of Bolivina granti/pacifica and Epistominella obesa respectively increase and decrease, and Bolivina aenariensis disappears. This faunal shift may be explained by changes in the amount and/or frequency of organic matter input. In the intercalated sandstones, Bolivina granti/pacifica, Eubuliminella bassendorfensis, and Epistominella obesa are still the most abundant species, with variable minor contributions of uvigerininds, Bolivina advena and shallow-water taxa such as Buccella peruviana. Notably, the faunal composition of these sandstones differs from neritic upper Tortonian to lower Messinian and upper Pliocene sandstones below and above the studied section, respectively, in which cibicids and Buccella spp. are dominant. In further steps, increased resolution of the assemblage data and statistical analysis combined with sedimentological data will provide more insights into the depositional processes to explain the observed sedimentary cycles. Understanding these processes will help to interpret the δ18O record and potentially establish a sequence stratigraphic framework for the section. This study contributes to CRC 1211 “Earth-Evolution at the dry limit”, funded by the Deutsche Forschungsgemeinschaft (DFG).

In modern oceans, upwelling processes are responsible for high biological productivity and low sea surface temperatures at coastal zones. Upwelling may have intensified during the late Neogene in the eastern South Pacific due to the strengthening of the Humboldt Current System. Records of Neogene coastal upwelling are preserved in outcrops along the coast of north-central Chile (~ 26°S to 28°S) as diatomaceous mudstone deposits of the Neogene Bahía Inglesa Formation. To place such records in a broader paleoceanographic context, however, their stratigraphic assessment still needs refinements. Our work presents a multiproxy dataset to provide a stratigraphic framework for the Bahía Inglesa Formation at Quebrada Tiburón (27°42' S, 70°59' W), one of the southernmost outcrops of diatomaceous mudstone. Our approach is based on tephrochronometry, strontium isotope chronology (mollusk shells 87Sr/86Sr), and calcareous nannoplankton, diatom, and planktonic foraminifera biostratigraphy. Zircon crystals separated from a volcanic ash layer at the base of the sequence were analyzed by laser ablation ICP-MS for U-Pb dating. The youngest cluster of five concordant zircon crystallization ages indicates a tephra deposition after 8.68 ± 0.15 Ma. The 87Sr/86Sr analyses were performed on an oyster and a pectinid from sandstones underlying the diatomaceous mudstone using high-precision MC-ICP-MS measurements. The corrected and adjusted 87Sr/86Sr ratios resulted in 8.12 ± 0.40 Ma and 6.10 ± 0.25 Ma ages. The microfossil biostratigraphy was based on First (FAD) and Last Appearance (LAD) datums of biostratigraphic markers from the diatomaceous mudstone. The presence of mainly Miocene diatoms (e.g., Actinocyclus ingens, Cavitatus joseanus, and Nitzschia fossilis) and the planktonic foraminifera Neogloboquadrina acostaensis (sinistral) indicate a Tortonian age for the base of the diatomaceous mudstone. The Messinian-Zanclean boundary was identified in the middle interval of the mudstone by the disappearance of the calcareous nannoplankton species Calcidiscus pataecus and the appearance of Helicosphaera sellii and Umbilicosphaera sibogae. This interpretation is supported by the continuity and limit of the diatoms Actinocyclus ellipticus, Azpeitia nodulifer, and Coscinodiscus plicatus overlapping with Hemidiscus cuneiformis. A Zanclean age was attributed to the upper part of the mudstone sequence due to the co-occurrence of the calcareous nannoplankton species Reticulofenestra pseudoumbilicus and Sphenolithus moriformis, the diatoms Actinocyclus ellipticus, the co-occurrence of the diatoms Nitzschia fossilis and Shionodiscus oestrupii, and the planktonic foraminifera Globoconella miotumida and Sphaeroidinellopsis seminulina. The following sandstones contain Pliocene mollusks. Although inconsistencies between biostratigraphic data of taxa from different microfossil groups were observed (likely due to the lack of a local biozonation appropriate for the upwelling context), our dataset suggests a late Tortonian to Zanclean (8.68 to 3.5 Ma) age constraint for the succession and late Messinian to Zanclean (6.09 to 3.5 Ma) age for the diatomaceous mudstone. Further studies will apply our stratigraphic constraints for paleoenvironmental reconstructions. This research is part of the CRC 1211 “Earth-Evolution at the dry limit” project, funded by the German Research Foundation (DFG).

The Gulf of Corinth is a relatively young (

Diatom-rich sediments exposed along the coastline of northern and central Chile are prominent archives of coastal upwelling properties in the Neogene. Unlocking these archives is fundamental to evaluate the potential significance of changing sea surface temperatures for landward moisture transport and palaeoclimatic fluctuations in the Atacama Desert. One of the southernmost occurrences of Neogene diatom-rich sediments is known from a series of quebradas, i.e. seaward ravines, on the Tongoy Pensinsula (30.3°S). The diatomaceous muds, previously correlated with the Middle to Upper Miocene, have been deposited in the Tongoy Paleobay. Here we present new bio- and magnetostratigraphic data from a 3.5 m-thick section of diatomaceous muds in the Quebrada Las Salinas together with a preliminary assessment of the depositional environment. While calcareous microfossils are absent, the sample material is rich in silicious microfossils. Diatoms are the predominant group, while silicoflagellates, ebridians, radiolarians, and sponge spicules contribute to a lesser extent. Co-occurrences of the diatom species Nitzschia fossilis and Shionodiscus oestrupii constrain the diatomaceous muds to an age < 5.7-5.9 Ma. Together with normal magnetic polarity at the base of the section, the lowermost age limit is further refined to an Early Pliocene age < 5.23 Ma (base of the Thvera subchron). Occurrences of the diatom species Rouxia californica in the upper part of the diatomaceous muds suggest an upper age limit within the Zanclean. The results demonstrate for the first time that diatomaceous muds in the Tongoy Paleobay extend well into the Pliocene. Comparison with previous studies suggests that diatom-rich deposits in the study area may be highly diachronous within and between quebradas. The microfossil assemblages suggest that coastal upwelling was prevalent in the Tongoy Paleobay during the Early Pliocene. Diatom assemblages are dominated by planktonic and meroplanktonic taxa that prefer cold, nutrient-rich surface waters of coastal upwelling such as Chaetoceros and its resting spores, Thalassionema nitzschoides, Coscinodiscus spp., and Actinoptychus senarius. Cold surface waters are also indicated by high abundances of Distephanus spp. in the silicoflagellate assemblages. Benthic taxa are very rare, suggesting water depths of 100-150 meters. The Early Pliocene diatom assemblages more closely resemble those of today’s upwelling in Eastern equatorial Pacific and off the northern Peruvian continental margin than off central Chile. This may suggest a range of surface temperatures at least comparable to or even warmer than off central Chile today, and significantly enhanced primary productivity. This preliminary assessment will be further evaluated through detailed statistical analysis. This study is part of the CRC 1211 “Earth-Evolution at the dry limit” project, funded by the Deutsche Forschungsgemeinschaft (DFG).

The Miocene Climatic Optimum (MCO) represents a climate period characterized by lower ice volumes and temperatures that were 3-4°C warmer than today. Indian Ocean Sub-Antarctic Mode Water (SAMW) is primarily formed south of 30°S and is the main return path for deep waters to the surface, migrating and intermixing northwards at Intermediate Water (IW) depths. The modern SAMW transports nutrients into the lower latitudes, strongly impacting mid- and low latitude productivity. During warmer climates, decreasing sea ice may increase nutrient trapping in the Southern Ocean, reducing the nutrient flux through SAMW into the lower latitudes. To better understand trajectories of nutrient fluxes in future climate change scenarios studies in past warm climate analogues of the near future – such as the MCO – are necessary. Thus, we use Ocean Drilling Project (ODP) Site 752, located on Broken Ridge in the southeastern Indian Ocean at a water depth of 1086.3 m, as a key location for understanding changes in IW conditions. This study aims to reconstruct paleoenvironmental conditions and bottom-water oxygenation at ODP Site 752 during the Middle to Late Miocene (15-8 Ma) using benthic foraminifera assemblages as a proxy for bottom-water-oxygenation and the enhanced Benthic Foraminifera Oxygen Index (eBFOI) for calculating dissolved oxygen content. We combine these assemblage data with Mg/Ca ratios of Cibicidoides wuellerstorfi and Cibicidoides mundulus as a proxy for bottom water temperatures (BWT). For reconstructing sea surface temperatures (SST), and temperatures from the open ocean thermocline, the Mg/Ca data were additionally gathered on the foraminifera species Globigerina bulloides (SST) and Globorotalia menardii (thermocline). We aim to analyze temperature variability through the water column to investigate influxes from cooler water bodies by increasing SAMW intensity and compare our new temperature data with our benthic foraminiferal assemblages. Therefore, we provide novel insights into Late Miocene IW circulation changes and deep water mass variation with the progressive northward shift of the Subantarctic Tropical Front (SAF).We present a high-resolution record of benthic foraminifera, tracing paleoenvironmental changes in deep water masses in addition to IW variation in the southeastern Indian Ocean. After the MCO, benthic foraminifera assemblages, and respectively the eBFOI indicate a relatively high oxic environment. Starting around 11 Ma, we first detect an increase of dysoxic conditions and deep infaunal foraminifera, e.g. the genus Bolivina spp., with minimal variation in the dissolved oxygen content of the bottom water. Such an assemblage shift is contemporary with increased current winnowing following the northward migration of the SAF. Furthermore, the higher abundance of epiphytic species Cibicidoides wuellerstorfi and Lobatula lobatula, and also Vulvulina pennatula as an elevated epifauna, support an increase in bottom current energy at Broken Ridge from 15 to 11 Ma. Combined, our assemblages and Mg/Ca paleotemperature data suggest that the strengthening of the SAMW and Antarctic Intermediate Water formation in the Late Miocene, since about 11 Ma, resulted in notable changes in bottom water conditions at Broken Ridge, including the increase of current winnowing.

The Atacama Desert located in northern Chile is one of the driest places on earth. The factors determining recent hyperarid climate conditions and their interplay and variability on interannual and decadal time scales are generally understood. Evidence for wetter (yet arid) conditions in the Atacama’s past is mostly provided by ephemeral lacustrine and fluvial deposits. The main watercourse of the Atacama Desert is the Rio Loa sourced by rainfall in the Andean mountains. Information on changes in the terrestrial supply to the ocean is recorded in marine sediments off the Rio Loa mouth.Sediment core SO-104-52KL has been collected on the upper continental slope (∼340 m water depth, 21°S) off the Rio Loa during cruise 104, Leg 3 by RV Sonne in 1995. The preliminary chronology of the core based on 14C datings constrains the top and base of the core to 16 and 42 ka, respectively, with a mean sedimentation rate of 30-40 cm kyr-1. These very high average sedimentation rates allow reconstructions of the paleoceaonographic and paleoclimatic conditions during marine isotope stages (MIS) 3 and 2 on millennial to centennial time scales. The location of the core on the continental slope off the Rio Loa mouth allows for the parallel evaluation of the Humboldt Current System and Andean rainfall as moisture sources for the Atacama Desert.Proxy data for upwelling properties are established from microfossil assemblages and lipid biomarkers. Preliminary results show that foraminifera are abundant and well-preserved in the upper 4 m of the core. While planktonic foraminifera are rare, benthic assemblages are rich. In total, 24 genera and 49 species of benthic foraminifera were distinguished. The three taxa Bolivina, Bulimina, and Suggrunda, which indicate hypoxic to dysoxic conditions at the seafloor, make up most of the individuals. The dominance of hypoxia tolerating taxa indicates strong upwelling conditions via the presence of a pronounced Oxygen Mimimum Zone impinging on the upper continental slope. These data are put into context with relatively warm sea surface temperatures of average 21 °C as derived from alkenone data. Together with XRF data and grain-size analyses, both applied to characterize the terrestrial input by the Rio Loa, the expected proxy data will provide new insights into the dynamics of land-ocean coupling between the Atacama Desert and the eastern Pacific Ocean.This study is part of the CRC 1211 “Earth-Evolution at the dry limit” project, funded by the German Research Foundation (DFG).

Concerning climatic conditions during the Miocene Climate Optimum (MCO), global temperatures were about 3-4°C warmer than modern, and characterized by globally lower ice volume. Indian Ocean Sub-Antarctic Mode Water (SAMW) is primarily formed south of 30°S and is the primary return path for deep waters to the surface, migrating and intermixing northwards at Intermediate Water (IW) depths. Today, the SAMW carries access nutrients into the lower latitudes, strongly impacting latitude productivity. During warmer climates, decreasing sea ice may increase nutrient trapping in the Southern Ocean, reducing the nutrient flux through SAMW into the lower latitudes. Thus, the MCO may indicate future climate, nutrient transport, and SAMW formation by exploring differences between cooler (modern) and warmer (MCO) climates. Ocean Drilling Project (ODP) Site 752, located on Broken Ridge in the southeastern Indian Ocean at a water depth of 1086.3 m, is a key location for investigating changes in IW conditions in the Indian Ocean after the MCO and the Middle Miocene Climatic Transition (MMCT). In particular, the reactions to global warming and the reorganization of oceanic and atmospheric circulation following the MCO and MMCT can be detected. This also includes the analysis of SAMW, Antarctic Intermediate Water (AAIW), and Tasman Leakage (TL). The present study aims to reconstruct paleoenvironmental conditions and bottom-water oxygenation at Site 752 during the Middle to Late Miocene (15-8 Myrs). To achieve this, we apply benthic foraminifera assemblages as proxies for bottom water oxygenation, for example, enhanced Benthic Foraminifera Oxygen Index (eBFOI), paleoproductivity, and stable carbon and oxygen isotopes. Initial results in the Middle to Late Miocene show an occurrence of oxic benthic foraminifera at a relatively constant abundance, especially in the early Late Miocene. In addition, in a relatively high oxic environment, an increase of dysoxic conditions occurred during the early Late Miocene, with peaks of abundance in dysoxic and deep infaunal benthic foraminifera. A co-occurrence of infaunal dysoxic and epifaunal oxygen-rich species is accompanied by enhanced current winnowing and an increase of nutrient flux during the Late Miocene (Lyu et al., 2023; DOI: 10.1029/2023PA004761). These data indicate that during the Late Miocene, since approximately 10 Ma, the strengthening of SAMW and AAIW formation resulted in notable changes in bottom-water conditions at Broken Ridge, such as increased current winnowing. The observed changes in IW are potentially linked to the shift of the southern hemisphere westerlies towards the north and the subsequent northward migration of the frontal system in the southern hemisphere around Antarctica after 12 Ma.

Ascidians, or sea squirts, are sac-like sessile tunicates commonly found in modern seas. Although the oldest ascidians, or at least ascidian-like tunicates, are mid-Cambrian in age, the quality of the ascidian fossil record is extraordinarily poor. It mostly consists of isolated finds or low-diversity assemblages, often represented by mineral spicules. Our study reports the world's most diverse assemblage of ascidian spicules, originating from the Middle Miocene Bogutovo Selo near Ugljevik, Bosnia and Herzegovina. This material includes 31 spicule types, with four assignable to species (Lissoclinum cf. perforatum, Polysyncraton cf. bilobatum, Didemnum cf. vexillum and D. cf. leopardi) and 10 to genera, all belonging to aplousobranchiate ascidians. Comparing our findings with those of two other studies that use modern biological nomenclature, our assemblage shows a closer resemblance to the distant Eocene Australian assemblage than to the Miocene ascidians from Eastern Paratethys. This suggests the persistence of a once-homogeneous and widely distributed Eocene fauna into the Miocene, while the Eastern Paratethyan basin developed an endemic fauna after the isolation of Eastern Paratethys from the open sea. Some taxa of our assemblage currently inhabit the Mediterranean Sea. The discovery of one species in distant South African waters suggests that tectonic and environmental changes during the Late Miocene, including the closure of the Gibraltar Strait and prior disconnection from the Indian Ocean, may have limited its survival to remote refugia. The study underscores the importance of including spicules in reconstructing ascidian faunas in the geological past, an area that has been surprisingly understudied.

The holotype of Sigmoilopsis ottnangensis Cicha, Čtyroká and Zapletalová 1973 cannot be identified with certainty from the collection of specimens used in the original species description. Following the International Code of Zoological Nomenclature, the specimens should be considered syntypes. We herein designate a lectotype and paralectotypes for Sigmoilopsis ottnangensis from the original material to ensure taxonomic stability.

Benthic foraminifera colonize a wide range of marine environments including contourite drift systems. Contourites form elongated sedimentary bodies deposited under persistent contour-parallel bottom currents, where certain suspension-feeding foraminifera benefit from the entrained nutrient load. Their distribution patterns have been shown to be highly valuable for reconstructing ocean circulation at mid-latitudes. However, comparable faunal studies from the high-latitude North Atlantic are missing, a crucial region for global ocean circulation and the widespread deposition of contourites drifts. This study examines foraminiferal faunas > 250 µm from surface samples of the Björn and Gardar drifts in the Iceland Basin and the Eirik Drift south off Greenland. It serves as baseline for understanding the biogeographic patterns of benthic foraminifera from high-latitude contourites.The results show that four types of suspension-feeding species characterize different hydrodynamic environments. Bottom currents < 3 cm s -1 at the Björn Drift sustain assemblages rich in the finely branching, erect species Saccorhiza ramosa and Rhizammina algaeformis , which capture food particles with a pseudopodial net. The northern Gardar Drift displays intermediate flow velocities up to 10 cm s -1 and is dominated by tubular branching and facultative suspension-feeding species such as Rhabdammina abyssorum . Assemblages with abundant Rhabdammina abyssorum and Hoeglundina elegans colonize the southern detached and finer grained Gardar Drift. The Eirik Drift off Greenland with flow velocities of 12 to 22 cm s -1 displays a fauna different from the contourites of the Iceland Basin. Assemblages with attached Cibicidoides wuellerstorfi and Heterolepa broeckhiana largely determine the benthic community. Also attached species, but composed primarily of Cibicides lobatulus , Cibicides refulgens , and Cibicidoides pachyderma , settle at the Greenland continental margin in high energy areas with velocities up to 40 cm s -1 .

&lt;p&gt;Reduced landward moisture transport due to the cold upwelled surface waters of the Humboldt Current System (HCS) is one of the primary triggers of hyperarid conditions in the Atacama Desert. Marine sediments exposed along the coastline of northern Chile provide a unique archive of land-ocean coupling between coastal upwelling related HCS and paleoclimate in the Atacama Desert during the Neogene. Here we aim to establish a refined stratigraphic framework for the emplacement of diatom-rich deposits of the Bah&amp;#237;a Inglesa Formation at Quebrada Tibur&amp;#243;n (27&amp;#176;S).&lt;/p&gt;&lt;p&gt;The marine sediments exposed at Quebrada Tibur&amp;#243;n lie transgressively above the pre-Cenozoic basement. A c. 9m-thick succession of laminated diatomaceous muds is intercalated with sandy deposits. Benthic foraminiferal assemblages and test morphology reveal a shift from trochospiral and planospiral (predominantly epifaunal) to serial (infaunal) morphotypes between sands and diatomaceous muds, respectively. Together with plankton assemblages dominated by diatoms and &lt;em&gt;Globigerina bulloides&lt;/em&gt;, the diatomaceous muds reflect a highly productive coastal upwelling regime and low oxic, eutrophic conditions at the seafloor. However, occasional layers of bioturbation within the diatomaceous succession also imply phases of relaxed upwelling conditions. The new stratigraphic framework will thus allow the assessment of Neogene upwelling behavior and variability off Chile on orbital time scales.&lt;/p&gt;&lt;p&gt;Preliminary results based on calcareous nannoplankton, diatoms and planktonic foraminifera indicate a stratigraphic range from the upper Miocene (Messinian) to the lower Pliocene for the diatomaceous muds. Evidence from the &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O of the benthic foraminifera &lt;em&gt;Uvigerina peregrina&lt;/em&gt; further ties the upper part of the succession to an uppermost Zanclean age &lt; 3.9 Ma. In a next step, the stratigraphic framework will be further improved by new data from magnetostratigraphy, Sr isotopes, and tephrochronology.&lt;/p&gt;&lt;p&gt;This study contributes to CRC 1211 &amp;#8220;Earth-Evolution at the dry limit&amp;#8221;, funded by the Deutsche Forschungsgemeinschaft (DFG).&lt;/p&gt;

Benthic foraminifera provide key information for the reconstruction of ocean bottom currents. In the Iberian Margin Contourite Drift System, abundances of a distinct group of benthic foraminifera are controlled by the strength and nutrient load of bottom currents. This so-called elevated epifauna (EEF) comprises highly specialized suspension feeding benthic foraminifera attached to elevated substrates as an adaptation to strong bottom currents. Schönfeld (2002) demonstrated a direct relation between EEF abundances and Mediterranean Outflow Water strength at the Iberian Margin in modern surface samples and established EEF abundances as a bottom current proxy. Faunal and geochemical data from Pliocene-Pleistocene contourites drilled during IODP Exp. 339 in the Gulf of Cádiz, however, showed a poor correlation of EEF abundances with other bottom current proxy data, indicating a bias by depositional or taphonomic processes. The tectonically active Iberian Margin is characterized by a complex depositional environment shaped by alongslope and downslope transport. Taphonomic processes linked to transport and loss of foraminiferal tests during early fossilization potentially bias fossil EEF abundances in marine slope sediments and may result in overestimation of bottom current speeds. Our understanding of these taphonomic processes is still rather poor. Stable oxygen and carbon isotope ratios from foraminiferal tests in Pleistocene contourites and turbidites can be used to identify allochthonous tests and provide insights into the extent of downslope transport at the Iberian Margin. The aim of this study is to quantify the effects of taphonomic processes on fossil foraminiferal assemblages and to establish an improved EEF proxy method. The improved method will provide researchers with a reliable, well-calibrated and easily applicable tool for bottom current reconstruction. Reference: Schönfeld, J. (2002). A new benthic foraminiferal proxy for near-bottom current velocities in the Gulf of Cadiz, northeastern Atlantic Ocean. Deep Sea Research Part I: Oceanographic Research Papers, 49(10), 1853-1875.

This study presents new quantitative data on benthic foraminifera from three bathymetric transects of the Brazil (11-14°S, 420-1900 m) and Campos (22°S, 430-2000 m) basins. The quantity and quality of organic matter flux as well as substrate properties and hydrodynamic conditions at the sediment-water interface are identified as key parameters controlling assemblage distribution. Based on the total (stained and unstained) fauna, a distinct biogeographic divide between a Globocassidulina subglobosa/crassa assemblage in the Campos Basin and a rosalinid/bolivinid assemblage in the Brazil Basin occurs across the bifurcation of the South Atlantic Central Water into its southward subtropical and northward tropical branches. In the Campos Basin, coarser sediments, increased bottom current activity, and variable nutrient supply favor an assemblage of Globocassidulina subglobosa/crassa, Nuttalides umbonifer and Alabaminella weddellensis. Occurrences of cold-water coral mounds in 870 m provide an ecological niche favoring species such as Alabaminella weddellensis which benefit from trapped nutrients. The Brazil Basin is characterized by increased abundances of Rosalina and Bolivina, while Globocassidulina subglobosa/crassa is comparatively less frequent. Assemblages with G. subglobosa/crassa, Rosalina spp., Bolivina variabilis and Bolivina subreticulata are favored by a relatively high nutrient input at 14°S. Further north, assemblages with Bolivina subreticulata, Bolivina variabilis, Epistominella exigua, G. subglobosa/crassa are located beneath the velocity core of the North Brazil Undercurrent (NBUC), coinciding with more clayey sediments rich in TOC. Occurrences of delicate branching forms such as Saccorhiza ramosa indicate a more stable setting, distal to the main current. Rose Bengal stained (living) specimens are scarce in all three regions, as is typical for deep-sea foraminiferal faunas. Their patterns of species distribution largely reflect those observed for the total fauna.

Marine sediment core PS2719-1 represents a key sedimentary record for the reconstruction of the postglacial shelf evolution of the eastern Kara Sea west of the entrance to the Vilkitsky Strait. Sedimentological, chrono-logical, geochemical, mineral magnetic and micropaleontological data were used to investigate the sedimentary evolution of the area in unprecedented detail. Four phases of sedimentation were identified, which are closely related to sea-level rise and input from the Yenisei and Taymyr Rivers. Sedimentation likely commenced directly after regional deglaciation prior to 13.6 cal ka BP. Basal sediments are coarse grained and rich in terrestrial organic matter, which points to shelf erosion as the dominating sedimentation process. Around 13.6 cal ka BP Yenisei River water masses reached the area, causing a shift in heavy mineral assemblages and a distinct peak in magnetic susceptibility. This phase was followed by increased sedimentation rates during the early Holocene, which were related to high sediment supply from Lake Taymyr, possibly due to the opening of an ice dam in the Lower Taymyra River area. These sediments are characterized by high terrestrial organic matter accumulation, a fine-grained composition, and a heavy mineral assemblage reflecting the sediment source on the Taymyr Peninsula. High burial rates are reflected by high Mn contents. The transition to modern conditions commenced already around 8.5 cal ka BP and were fully established at ca. 5 cal ka BP, being documented in mineral magnetic evidence and foraminiferal assemblages and are characterized by more marine conditions and a strong influence of the Yenisei River.

Marie-Pierre Aubry, Kenneth G. Miller, Elena Turco, José Abel Flores, Andrey Gladenkov, Patrick Grunert, Frits Hilgen, Hiroshi Nishi, Ann Holbourn, Wout Krijgsman, Fabrizio Lirer, Werner E. Piller, Frédéric Quillévéré, Isabella Raffi, Marci Robinson, Lorenzo Rook, Jun Tian, Maria Triantaphyllou, Felipe Vallejo. Episodes 2022;45:445-53. https://doi.org/10.18814/epiiugs/2022/022008