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The Late Oligocene to Early Miocene flora of the Ban Pa Kha Subbasin (Li Basin, northern Thailand) provides a record of montane dry tropical oak-pine forests. The rich ensemble of Fagaceae typical of these forests might have existed in the wider region of Southeast Asia since Eocene times and various fossil plant assemblages represented both lowland (Fagaceae, Dipterocarpaceae) and upland (Fagaceae, Pinaceae) tropical forests. These findings are in conflict with previous interpretations of vegetation development in northern Thailand, which stressed that stratigraphically older (possibly Late Oligocene) spore and pollen assemblages in northern Thailand were markedly different from the modern tropical flora and had a distinct northern temperate character. A major change in climate would have caused a dramatic shift to tropical conditions since the Mid-Miocene. Considering palaeobotanical data from adjacent regions in Southeast Asia, we suggest that differences in spore and pollen assemblages in intermontane basins in northern Thailand are more likely to represent different facies and lowland/upland settings. Assembly of these forest ecosystems, typically comprising Quercus sections Cyclobalanopsis, Ilex and Quercus, pollen of Castaneoideae with affinities to Castanopsis and Lithocarpus, and extinct fagaceous genera such as Eotrigonobalanus, most probably dates back to the Eocene. The absence of oaks of Quercus section Cerris in the spore and pollen assemblage of the Ban Pa Kha Subbasin, despite this group being part of the modern vegetation, might reflect the late arrival (secondary radiation) of this chiefly temperate group in tropical Southeast Asia., This project was funded by the Prince of Songkla University, Thailand (project number SCI 6402006S), the Swedish Research Council (VR, grant number 2021-05849) and ASEA-UNINET Staff Exchange, One Month Scholarship 2017

The Late Oligocene to Early Miocene flora of the Ban Pa Kha Subbasin (Li Basin, northern Thailand) provides a record of montane dry tropical oak-pine forests. The rich ensemble of Fagaceae typical of these forests might have existed in the wider region of Southeast Asia since Eocene times and various fossil plant assemblages represented both lowland (Fagaceae, Dipterocarpaceae) and upland (Fagaceae, Pinaceae) tropical forests. These findings are in conflict with previous interpretations of vegetation development in northern Thailand, which stressed that stratigraphically older (possibly Late Oligocene) spore and pollen assemblages in northern Thailand were markedly different from the modern tropical flora and had a distinct northern temperate character. A major change in climate would have caused a dramatic shift to tropical conditions since the Mid-Miocene. Considering palaeobotanical data from adjacent regions in Southeast Asia, we suggest that differences in spore and pollen assemblages in intermontane basins in northern Thailand are more likely to represent different facies and lowland/upland settings. Assembly of these forest ecosystems, typically comprising Quercus sections Cyclobalanopsis, Ilex and Quercus, pollen of Castaneoideae with affinities to Castanopsis and Lithocarpus, and extinct fagaceous genera such as Eotrigonobalanus, most probably dates back to the Eocene. The absence of oaks of Quercus section Cerris in the spore and pollen assemblage of the Ban Pa Kha Subbasin, despite this group being part of the modern vegetation, might reflect the late arrival (secondary radiation) of this chiefly temperate group in tropical Southeast Asia., This project was funded by the Prince of Songkla University, Thailand (project number SCI 6402006S), the Swedish Research Council (VR, grant number 2021-05849) and ASEA-UNINET Staff Exchange, One Month Scholarship 2017

Kuphus is a genus of teredinid bivalves whose modern counterpart, K. polythalamius, colonises oxygen-poor and restricted marine environments enriched in plant remains. In the Oligocene, Kuphus colonies are quite abundant worldwide, but their depositional setting has never been studied in detail. We describe the first report of Oligocene Kuphus beds from the Iberian Peninsula, cropping out in platform deposits of the Prebetic (Southeastern Spain). By means of anterior endings and taphonomic characters as orientation of Kuphus tubes, fragmentation, packing and mixing with other fauna, four skeletal concentrations were distinguished: SkC A represents in situ colonies with anterior endings well preserved and with local dolomitisation around the tubes and was recorded in the inner lagoon; SkC B, with parallel and horizontally reoriented tubes, was formed by tidal currents; SkC C records high-energy events breaking down the tubes and resedimenting them close to the source area; SkC D is characterised by fragmented tubes mixed with other bioclasts, deposited by storms in the outer platform. The recorded skeletal concentrations are consistent with the environmental setting of K. polythalamius, but the morphological differences and the absence of data on the presence of plant remains could possibly reflect adaptations to higher variety of palaeoenvironments.

According to the latest report of the Intergovernmental Panel of Climate Change, Earth’s temperature will rise at least 1.5°C on average globally, and even 2-3 times more on the poles. Therefore, studying the geological past is important to determine the implications for the stability of the Antarctic ice sheet and sea ice. As we cannot travel back in time, this research uses the so-called sedimentary archive, existing of layers of ocean floor, from which remains of organisms, ocean currents and climate conditions can be derived. In this thesis research methods based on organic fossils and molecules obtained from layers of ocean floor are explored and improved upon and subsequently applied to reconstruct the history of the ocean close to the Antarctic ice sheet. This thesis describes the diversity of organic microfossils obtained from a core with sediments up to 11.000 years old, which serves as reference material for further study. To improve our understanding of the environmental conditions that these microfossils preferred, their abundance is compared to data on meltwater discharge, surface water temperature and sea-ice concentrations. Application of these methods on a core containing the previous interglacial, shows that during periods of warming processes were at play that resemble the processes we see around Antarctica today, such as an increase in meltwater discharge. A reconstruction of the period between 34 and 26 million years ago, when CO2 concentrations were comparable to today, show that seawater temperatures were on average 17°C and there was only little sea ice present.

Two new species of ctenodactylid rodents, Prodistylomys taatsinius sp. nov. and Prodistylomys mongoliensis sp. nov., are described from the Valley of Lakes, Central Mongolia. They represent the first record of this genus in Mongolia. Prodistylomys is characterized by a simple dental pattern and high hypsodonty, reflecting an adaptation for tough vegetation in a dry environment, which is congruent with the aridification event that took place during the Late Oligocene and Early Miocene. We performed the most complete phylogenetic analysis combining the largest sampling in the family Ctenodactylidae and the best-represented stratigraphical distribution for the sample. This allowed us to propose that the origin of ctenodactylids lies in East Asia during the Eocene, and after that, the group dispersed through western Asia, Europe, and Africa. The presence of several similar rodent taxa in Mongolia, Kazakhstan, and China confirms that these areas were part of a large bioprovince covering most of central Asia during the Oligocene and Early Miocene., Universidad Complutense de Madrid, Ministerio de Ciencia e Innovación, European Union, Austrian Science Fund, Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub

Up to fourteen sub-bituminous coal beds are hosted within the Oligocene Bobov Dol Basin. Among them, six (numbered I to VI from base to top) are considered economically significant. In this study, ninety samples from five of the main seams (I-V) and a locally mined sub-seam (Ia) were characterized by maceral analysis and ash yield determination. The coal is composed of huminite (avg. 86.6 vol.%), liptinite (avg. 17.5 vol.%) and minor inertinite (avg: 1.5 vol.%). Maceral composition is dominated by gymnosperm-derived telohuminite (up to 72.0 vol.%) with resinite (up to 28.0 vol.%) and exsudatinite (up to 16.0 vol.%) cell infillings, embedded in attrinitic (avg. 21.0 vol.%) or densinitic (avg. 17.0 vol.%) groundmass. Most samples also contain abundant leaf-derived huminte (phyllo-huminite, up to 29.0 vol.%) in association with cutinite (up to 8.0 vol.%) and fluorinite (up to 5.0 vol.%). Low to moderate ash yields (< 25 wt.% for most samples) coupled with low to moderate values of the maceral indices, namely TPI < 3 (for ~80% of the samples) and GI < 3 (for >53% of the samples), and low values of the GWI < 1 (for 81% of the samples), denote organic matter deposition within an oligo- to mesotrophic topogenous mire with (ground)watertable beneath the peat surface. Reconstruction of paleoenvironmental settings based on maceral analysis (Fig. 1) argues for plant matter accumulation under marginal aquatic (seam Ia) and moderately wet- to dry-forested mires (seams I-V). Abundance of resinite and fluorinite-rich (phyllo-)huminite indicates development of conifer-dominated forests (likely deciduous gymnosperms), perhaps within a background of herbaceous plants and/or deciduous shrubs. The data is compatible with the previously reported preliminary organic geochemical data for part of the seams (Zdravkov et al., 2021).

Recently, the evolutionary history of the Caribbean mangroves has been reconsidered using partial palynological databases organized by the time intervals of interest, namely Late Cretaceous to Eocene for the origin, the Eocene-Oligocene transition for major turnover and Neogene to Quaternary for diversification. These discussions have been published in a set of sequential papers, but the raw information remains unknown. This paper reviews all the information available and provides the first comprehensive and updated compilation of the abovementioned partial databases. This compilation is called CARMA-F (CARibbean MAngroves-Fossil) and includes nearly 90 localities from the present and past Caribbean coasts, ranging from the Late Cretaceous to the Pliocene. Details on the Quaternary localities (CARMA-Q) will be published later. CARMA-F lists and illustrates the fossil pollen from past mangrove taxa and their extant representatives, and includes a map of the studied localities and a conventional spreadsheet with the raw data. The compilation is the most complete available for the study of the origin, evolution and diversification of Caribbean mangroves, and is open to modifications for adapting it to the particular interests of each researcher.

Overpressure build up in the clay-rich succession between sea floor and the top of the Chalk Group in the area around wells North Jens-1 and Fasan-1 in the Danish sector of the Central Graben, North Sea was examined by forward modelling. "Overpressure", i.e. fluid pressure higher than hydrostatic pressure, is expressed here in terms of both the difference between pore pressure and hydrostatic pressure at a given depth and the ratio between these pressures. Pore pressure changes over time were estimated by numerical simulation of post-Danian depositional processes, incorporating sea level changes and variations in sedimentation rate. Results show that the deposition of the post-Danian ("overburden") succession led to overpressure build up both in the overburden itself and in the underlying sediments (the so-called "underburden"). The largest estimated present-day overpressures (4.9-5.6 MPa, 23-26% above hydrostatic) occur at the base of the overburden, while an overpressure of up to 5.5 MPa was calculated to occur in the underburden. Variations in sedimentation rate appeared to have influenced the build-up of overpressure in the overburden, although no significant effect was found in the underburden.The results indicate that more than 50% of the present-day overpressure in the overburden was generated in the last 5.3 million years, i.e. during the Pliocene and the Quaternary. When variations in sedimentation rate during the Miocene were included in the modelling calculation, this proportion increased to nearly 70%. A decrease in sedimentation rate in the mid-Miocene (Serravallian, 15-11.2 Ma) and the late Miocene (Messinian, 7.5-5.3 Ma) resulted in the dissipation of overpressures generated previously when the sedimentation rate was higher. About 60% of the overpressure generated in the Miocene developed during the Tortonian but only 14% during the Messinian.Water depth appears to influence the overpressure magnitude. Sea level changes played a minor and short-liv

Evidence of Paleogene subduction in the Western Mediterranean is scattered throughout high-pressure (HP) events in polymetamorphic basement terrains of disputed and differing provenance exposed along the margins of deep basins formed during Miocene to Quaternary slab retreat. The reconstruction of the original subduction geometry is often hindered by pervasive Miocene high-temperature (HT) ductile overprinting of earlier HP events. Here, we report rutile U¿Pb ages, EBSD-determined microstructures and thermodynamic modeling in eclogites from the upper-plate domain of the Betics (Ojén nappe, Alpujárride complex). These data show that the Ojén eclogite peak mineral assemblage formed during HP (1.3 ±0.15 GPa) and HT (700 ± 25 °C) ductile flow in the early Oligocene (30 ± 2.5 Ma). We interpret this event as a collisional phase linking Ojén eclogites to the Paleogene subduction of the western Tethys. Contrasting P¿T gradients of eclogites and arc volcanism between Corsica¿Calabria and Kabylies¿Betics point to a highly segmented orogenic system. NW¿SE-oriented transform faults separated a continental collision domain to the South from an oceanic subduction to the NE, with two subducting slabs ¿Calabrian and Algerian¿ retreating respectively towards the E and SE. Early Eocene inversion of the European and Maghrebian margins and ensuing early Oligocene collision resulted in (U)HP¿HT metamorphism in the Alpujárride and Kabylies. This orogen underwent extensional collapse in the late Oligocene-Aquitanian, before further shortening and the intracrustal emplacement of the Ronda peridotite. The upper plate Ojén eclogites and orogenic peridotites drifted westwards following the retreating Betics¿Rif Tethys slab in the early Miocene, after transform collapse that induced HP subduction of the SE Iberian margin below the Alpujárrides.

The record of the Eocene-Oligocene Transition (EOT) in the alluvial-lacustrine successions of the Ebro Basin is reviewed in the light of a refined stratigraphic correlation framework. Earlier works provided a magnetostratigraphic correlation for this time interval that was meant to fit with the available small-mammals biochronology (Costa et al., 2011; Barberà et al., 2001). A key constraint to this study was the Santpedor locality (Agusti et al., 1987; Vianey-Liaud et al., 2019), which yielded a characteristic post-Grande Coupure small mammal assemblage, then attributed to the lowest Oligocene. The extended magnetostratigraphy provided in this work challenges earlier correlations and puts forward an alternate scenario that reveals a severe misfit with the continental biochronology framework based on the fossil mammal record. Or results indicate that the locality of Santpedor, bearing a post-Grande Coupure assemblage is correlated to the late Eocene, with an age 1.5 Myr older than the EOT, thus challenging the view that the Grande-Coupure marks the onset of the Oligocene in the continental realm. The significance of this discrepancy in terms of heterochrony of biostratigraphic events, the punctuated character of faunal replacement across the EOT, and time lags between the marine and continental realms may need to be addressed. The magnetostratigraphic record obtained across the EOT transitions reveals the presence of a short geomagnetic event of normal polarity within chron C13r, and very close to the Eocene-Oligocene boundary (Fig. 1). Despite not being yet reported in the GPTS, this event is recognized in several other records in different geographic locations around the globe, and sedimentary environments (Valero et al., 2015; Tauxe et al., 1984; Katz et al., 2008; Miller et al., 1993). Thus we suggest that it truly represents a global geomagnetic feature that deserves the category of either subchron (C13r.1n) or cryptochron (C13r-1). The results of this work emp, En este trabajo se analiza el registro de la Transición Eoceno-Oligoceno (EOT) en las sucesiones aluviales-lacustres de la cuenca del Ebro, a partir de la revisión de las correlaciones estratigráficas y de nuevos datos magnetoestratigráficos. Trabajos anteriores proporcionaron una correlación para este intervalo de tiempo que perseguía encajar con el marco biocronológico existente (Costa et al., 2011; Barberà et al., 2001). Una información clave fue la localidad de Santpedor (Agusti et al., 1987; Vianey-Liaud et al., 2019), que había aportado una asociación de micromamíferos post-Grande Coupure, evento de renovación de faunas terrestres que clásicamente se ha interpretado como marcador de la base del Oligoceno. Los nuevos registros magnetoestratigráficos proporcionados en este trabajo presentan un escenario alternativo contradictorio con la información biocronológica. Los nuevos resultados indican que la localidad de Santpedor se correlaciona con el Eoceno superior, con una edad 1.5Myr anterior al EOT, desafiando así la visión de la Grande-Coupure como evento que da inicio al Oligoceno en el continente. La importancia de esta discrepancia en términos de heterocronía de eventos bioestratigráficos, el carácter puntuado del reemplazo de la fauna a lo largo del EOT y los desfases de tiempo entre los reinos marino y continental, es un aspecto que merecerá discusión. El registro magnetoestratigráfico de la transición EOT revela la presencia de una breve magnetozona de polaridad normal que se correlaciona con la parte superior del cron C13r, muy próxima del límite Eoceno-Oligoceno, y que no tiene su registro en la escala de tiempo de polaridad geomagnética (Fig. 1). Una magnetozona en una posición equivalente se ha reconocido en registros de diferentes lugares del planeta y ambientes sedimentarios (Valero et al., 2015; Tauxe et al., 1984; Katz et al., 2008; Miller et al., 1993). Por lo tanto, sugerimos que esta magnetozona realmente representa un evento geomagnético global

Anthracotheres and entelodonts are large mammals with peculiar morphological characteristics that combine plesiomorphic and derived features. The unusual anatomy of anthracotheres shows a morphological resemblance to pigs and hippos and their bunoselenodont low-crowned molars have been interpreted as an adaptation to frugivorous/folivorous diets. Entelodonts share cranial and dental similarities to pigs and carnivores, and this has been interpreted as an adaption to opportunistic omnivore diets, hunting/scavenging, or bone-crushing (cf. hyenas). The objective of the present study is to use dental microwear analysis to test these assumptions and to infer the diet of anthracotheres and entelodonts. Dental microwear was quantified on the upper and lower molars using a stereomicroscope. To assess the dietary traits of the fossil samples, the results were compared to a dataset of extant large mammals covering ten dietary categories. The microwear features indicate different diets for Anthracotherium sp. and Entelodon magnus. Our sample of entelodonts shows an omnivorous diet similar to that of the wild boar, and it probably varied considerably between seasons. The anthracotheres we analysed were opportunistic browsing, frugivore, and grazing herbivores. During the Oligocene, these two taxa occupied ecological niches characterised by a large diversity of food resources. The results of the study offer further insights into the characteristics of the digestive system in fossil artiodactyls. The large dataset used in this research opens new perspectives for the dietary reconstruction of poorly known mammal taxa by considering a wide range of diets.

It is generally believed that a large scale Antarctic ice sheet formed at the Eocene-Oligocene transition (34.44-33.65 Ma). However, oxygen isotope excursions during the late Eocene (38-34 Ma) and geomorphic evidence of glacial erosion suggest that there were ephemeral continental scale glaciations before the Oi-1 event. Here, we investigate the Antarctic ice sheet evolution over a multi-million year timescale during the late Eocene up to the early Oligocene with the most recent estimates of carbon dioxide evolution over this time period and different bedrock elevation reconstructions. A novel ice sheet-climate modelling approach is applied where the Antarctic ice sheet model VUB-AISMPALEO is coupled to the emulated climate from HadSM3 using the coupler CLISEMv1.0. Our modelling results show that short-lived continental scale Antarctic glaciation might have occurred during the late Eocene when austral summer insolation reached a minimum in a narrow range of carbon dioxide concentrations. The Antarctic ice sheet first reached the coast in Prydz Bay and later in the Weddell Sea region, supporting the glaciomarine sediments dated prior to the EOT.

The fossil record of octocorals from Cenozoic marine strata of western North America is quite limited, and they have not been reported previously from rocks in Washington State, USA. Two late Oligocene specimens from the upper part of the Lincoln Creek Formation in western Washington, referred to Radicipes? sp., are the first fossil record of the family Chrysogorgiidae. The family Isididae is represented by an internode and two holdfasts identified as Isidella sp. collected from the Oligocene Pysht Formation, along with specimens questionably identified as Lepidisis sp., possibly the first fossil record for this genus. Together, these are the first confirmed fossils of the Alcyonacea from north of California in western North America. The axes of sea pens from several late Eocene or early Oligocene localities in the Lincoln Creek Formation in the central part of western Washington, and the Pysht and Makah formations on the north side of the Olympic Peninsula, are the first fossil record for the Pennatulacea from western North America; all are tentatively referred to the genus ‘Graphularia’. Large axes from the Lincoln Creek Formation and Makah Formation are referred to ‘Graphularia’ (?) aff. sasai, because they are similar to the species known only from late Eocene and early Oligocene rocks in Japan.

We describe a new genus of the chemosymbiotic bivalve family Vesicomyidae, Squiresica, for two Oligocene species, previously assigned to Archivesica, from western North America. Squiresica is characterized by a small and weakly inflated shell, a small to nearly absent pallial sinus, an Archivesica-like hinge dentition, with an indistinct to well incised lunular incision. Two species are assigned to this new genus: the type species, S. knapptonensis from western Washington State, USA, and S. marincovichi from Oligocene strata of Alaska, USA. Squiresica knapptonensis had previously been described from the upper Oligocene of the Lincoln Creek Formation; further specimens are here reported from a newly discovered seep deposit in the lower Oligocene part of the Lincoln Creek Formation., We thank Green Diamond Resources for continuing to allow access tolocalities on their land, and Mark Golliet (Green Diamond, Shelton,Washington office) for facilitating this access. We are grateful for Columbia Land Trust for allowing access to the Knappton localities. Financial support was provided by Vetenskapsrådet (Swedish ResearchCouncil) through grant 2016-03920 to SK.

The fossil record of octocorals from Cenozoic marine strata of western North America is quite limited, and they have not been reported previously from rocks in Washington State, USA. Two late Oligocene specimens from the upper part of the Lincoln Creek Formation in western Washington, referred to Radicipes? sp., are the first fossil record of the family Chrysogorgiidae. The family Isididae is represented by an internode and two holdfasts identified as Isidella sp. collected from the Oligocene Pysht Formation, along with specimens questionably identified as Lepidisis sp., possibly the first fossil record for this genus. Together, these are the first confirmed fossils of the Alcyonacea from north of California in western North America. The axes of sea pens from several late Eocene or early Oligocene localities in the Lincoln Creek Formation in the central part of western Washington, and the Pysht and Makah formations on the north side of the Olympic Peninsula, are the first fossil record for the Pennatulacea from western North America; all are tentatively referred to the genus ‘Graphularia’. Large axes from the Lincoln Creek Formation and Makah Formation are referred to ‘Graphularia’ (?) aff. sasai, because they are similar to the species known only from late Eocene and early Oligocene rocks in Japan.

We describe a new genus of the chemosymbiotic bivalve family Vesicomyidae, Squiresica, for two Oligocene species, previously assigned to Archivesica, from western North America. Squiresica is characterized by a small and weakly inflated shell, a small to nearly absent pallial sinus, an Archivesica-like hinge dentition, with an indistinct to well incised lunular incision. Two species are assigned to this new genus: the type species, S. knapptonensis from western Washington State, USA, and S. marincovichi from Oligocene strata of Alaska, USA. Squiresica knapptonensis had previously been described from the upper Oligocene of the Lincoln Creek Formation; further specimens are here reported from a newly discovered seep deposit in the lower Oligocene part of the Lincoln Creek Formation., We thank Green Diamond Resources for continuing to allow access tolocalities on their land, and Mark Golliet (Green Diamond, Shelton,Washington office) for facilitating this access. We are grateful for Columbia Land Trust for allowing access to the Knappton localities. Financial support was provided by Vetenskapsrådet (Swedish ResearchCouncil) through grant 2016-03920 to SK.

A partial skeleton of a pregnant shark with nine embryos was found in the clay pit of the Grube Unterfeld (“Frauenweiler”) locality near Rauenberg (Oligocene, Rupelian; Baden-Württemberg, southern Germany). The shark is identified as Carcharias cuspidatus (Agassiz, 1843). The cranium with upper and lower dentition, the majority of the vertebral column, parts of the pectoral fins, the dorsal fins, a pelvic fin, an anal fin and caudal fin, as well as skin patches with dermal denticles of the adult specimen and remains of the embryos are described and illustrated.

In the lower part of the Hamstead Member of the Bouldnor Formation (lower Rupelian, Oligocene) in the Isle of Wight (Hampshire Basin, England) a common gastropod has hitherto been incorrectly identified as Lutetiella conica (Prévost, 1821), a hydrobioid species from Lutetian (middle Eocene) strata of the Paris Basin. We have re-assessed its relationship and describe it as Nystia conoidalis n. sp. in the family Emmericiidae. Recognition of its relationships had been obscured by the vestigial development of the terminal varix and the less frequent and less severe occurrence of shell decollation.

A new decapod assemblage, from the Rupelian (early Oligocene) of the Aquitanian basin recovered in the outcrops of Gaas (Landes, France) is reported herein for the first time. Despite the fragmentary nature of the remains, at least six different taxa have been recognized at familial or generic level. Among them, the remains of Oligosella (Alpheidae) have been identified and these might represent the oldest record for the genus. A well-preserved carapace has allowed a new Leucosiidae crab to be described: Aquitainotlos gaasensis nov. gen. and nov. sp. The remains of Derilambrus, Palaeocarpilius, and Necronectes are also identified and described., Un nouvel assemblage de décapodes du Rupélien (Oligocène inférieur) du Bassin aquitain recueilli dans les affleurements de Gaas (Landes, France) est décrit ici pour la première fois. Malgré la nature fragmentaire des restes, au moins six taxons différents ont été reconnus au niveau familial ou générique. Parmi eux, des restes d’Oligosella (Alpheidae) ont été identifiés et pourraient représenter le plus ancien enregistrement de cette famille. Une carapace bien conservée a permis de décrire un nouveau crabe Leucosiidae : Aquitainotlos gaasensis nov. gen. et nov. sp. De plus, des restes de Derilambrus, Palaeocarpilius et Necronectes sont identifiés et décrits.

The Oligocene rodent assemblage from Gözükızıllı (Anatolia, Turkey) is described. The assemblage is relatively small, but it contains the new large and hypsodont baluchimyine Daxneria fragilis nov. gen. nov. sp. In addition, the ctenodactyline Sayimys, two new species of Eucricetodon: E. ruber nov. sp. and E. oculatus nov. sp. are present. Rare are the glirids Bransatoglis and Peridyromys/Microdyromys and a dipodid that could not be classified. The assemblage contains Asian and some European elements and is dated as early part of the late Oligocene (29-26 Ma). The small fauna from Gözükızıllı is important because only a few Paleogene rodent faunas are known from Asia Minor.

Deposition in the Gippsland Basin from the Late Cretaceous to the Miocene was characterised by extensive, wave-dominated shorelines in front of lower coastal plain peatlands. Using depositional architecture evident on seismic data, these deposits have been interpreted to consist of 23 discrete packages. Shoreface morphology ranges from progradational beaches to large, aggradational beach-barriers. While some of these beach-barrier-coastal plain units are progradational, on a multi-million-year timescale they retrograde. Transgression occurred from the Late Cretaceous to the Oligocene, with the main driver for this transgression likely basin subsidence. Despite large changes in paleoclimate, basin tectonics and ocean chemistry, the depositional style remains remarkably consistent. The Gippsland Basin experienced compressional tectonics which resulted in large anticlines forming across the basin. The timing of onset of compressional tectonics in the basin has been revised based on measurements of syn-tectonic sediment thickness changes across structures. These measurements indicate extensional growth faulting was occurring from the Late Cretaceous until the Late Eocene, and compressional structures did not begin growing until the Eocene-Oligocene transition. This research has brought the previously interpreted date for the onset of compressional tectonism in the Gippsland Basin forward approximately 10-20 Ma, from the previously interpreted early to mid-Eocene, to the Eocene-Oligocene transition. From the Palaeocene-Eocene transition to the Eocene-Oligocene transition a series of large channels incised into the top Latrobe Group - the Tuna and Marlin Channels. These channels have previously been interpreted as forming via fluvial processes associated with tectonic uplift. However, this research has shown that tectonic uplift occurred after channel incision, indicating uplift did not contribute to channel down- cutting. Additionally, well data reveals a marine origin f

The Quercy area of France is an important site for mammal palaeontology, yet 19th century collections of this area, such as the one in the Department of Palaeobiology, Naturhistoriska riksmuseet, remain understudied due to not being well updated taxonomically and correlated stratigraphically. An updated taxonomy was created for the postcranial material of the collections, as well as the dental material originally identified to the amphicyonid genera Amphicyon, Haplocyon and Pseudocyon through study of morphological characteristics and measurements. Most of the postcranial material was assigned to a family, which would allow comparison of different morphotypes to gain insight into questions on locomotion, posture and overall ecology. The dental material was reidentified to include the amphicyonids (bear dogs) Amphicyonidae gen. indet. sp. indet, Pseudocyonopsis, Cynelos and Haplocyon, as well as the mustelid Ischyrictis zibethoides. Stratigraphic ranges for the identified species were obtained from existing studies. This updated taxonomy would allow for future study of this material to improve the overall understanding of Quercy, as well as the taxa present in these localities.

The Gulf of California is a young example of crustal stretching and transtensional shearing leading to the birth of a new oceanic basin at a formerly convergent margin. Previous studies focused along the southwestern rifted margin in Baja California...

Evaluation of two historical collections of Louisiana vertebrate fossils housed in museum repositories revealed the presence of Paleogene shark and ray taxa that were heretofore unknown from the Gulf Coastal Plain of the USA. These include a new species of Carcharhinus, the sharks Isogomphodon sp., Mustelus sp., and Xiphodolamia ensis Leidy, 1877, and the ray Gymnura sp. Additionally, the first known lateral tooth of Eoplinthicus yazooensis Cappetta & Stringer, 2002 is described, improving our knowledge of the dentition of this extinct mobulid ray. The Isogomphodon sp. teeth represent the third fossil record of the genus from North America, whereas a single Mustelus sp. tooth is only the second Eocene record of this genus on the continent. One tooth of X. ensis provides the first record of the taxon in the Gulf Coastal Plain. The new Carcharhinus is distinct from all previously described Paleogene species, and it is the second Bartonian representative of the genus to be identified from deposits of the Eocene Mississippi Embayment. Two late Eocene Gymnura sp. teeth are the second Paleogene record of the genus in North America. These fossils improve our knowledge of Paleogene elasmobranch faunas on a local (Louisiana), regional (southeastern USA), and global scale.

Magnetostratigraphy is the key to put disparate chronological pieces together in a consistent chronostratigraphic framework. Provided that a long continuous record of reversals can be obtained from the sedimentary record, a correlation with the GPTS may be established. Magnetostratigraphy provides added value to the chronology as long as it keeps certain independence from external age constraints, such as bioevents calibrated elsewhere or radiochronologic data. An independent correlation is meant to not be anchored to a given chron on the basis of an external age constrain. Our experience recommends that external age constraints are best taken with flexibility, allowing for the searching of a best fit between the magnetic polarity sequence (in meters) and the GPTS (in million-years). This rationale relies on the fact that the Geological Time Scale is the tool that allows earth-scientist of many varied disciplines to understand and discuss about the dimension of time. But the time scale calibration is a task in continuous refinement. As the accuracy and precision of the dating tools increases, our ability to unravel lag times in geological processes increases too. As more refined data is produced, the calibration of the time scale reveals as an ongoing task rather than a final product. Here we present the case of the Eocene-Oligocene Transition (EOT) as recorded in alluvial-lacustrine sediments of the eastern Ebro Basin. An earlier work provided a magnetostratigraphic correlation that was in agreement with small-mammals biostratigraphic data. A key constraint to this study was the Santpedor locality, which yielded a characteristic post-Grand Coupure small mammal assemblage, then attributed to the lowest Oligocene. An extended record of the magnetostratigraphy has challenged the earlier correlation and puts forward an alternate scenario that reveals a misfit with earlier and recent biochronological interpretations of the fossil mammal record. The significance of this

The Quercy area of France is an important site for mammal palaeontology, yet 19th century collections of this area, such as the one in the Department of Palaeobiology, Naturhistoriska riksmuseet, remain understudied due to not being well updated taxonomically and correlated stratigraphically. An updated taxonomy was created for the postcranial material of the collections, as well as the dental material originally identified to the amphicyonid genera Amphicyon, Haplocyon and Pseudocyon through study of morphological characteristics and measurements. Most of the postcranial material was assigned to a family, which would allow comparison of different morphotypes to gain insight into questions on locomotion, posture and overall ecology. The dental material was reidentified to include the amphicyonids (bear dogs) Amphicyonidae gen. indet. sp. indet, Pseudocyonopsis, Cynelos and Haplocyon, as well as the mustelid Ischyrictis zibethoides. Stratigraphic ranges for the identified species were obtained from existing studies. This updated taxonomy would allow for future study of this material to improve the overall understanding of Quercy, as well as the taxa present in these localities.

The Paleogene coal-bearing deposits (Pinghu Formation) of the Xihu Depression form the most productive hydrocarbon source in the East China Sea Shelf Basin. Due to the lack of reliable magnetostratigraphic, paleontologic and geochemical/isotope data, these source rocks are still poorly dated. The absence of a robust time frame results in many disputes on the age and duration of the Pinghu Formation and hampers a thorough understanding of its sedimentary evolution. Here, we study the cyclic changes in the depositional environment that can be retrieved from seismic interpretation and sequence stratigraphic analyses of well log data ( e. g., stacking patterns, logging, and lithofacies changes). We recognize one second-order sequence, three third-order sequences and 12 fourth-order parasequences. Next, we construct a floating astronomical time scale by using power spectra and evolutionary fast Fourier transformation analysis on the gamma-ray data. Wavelength variations in the gamma-ray spectra show similar ratios as the astronomically-forced Milankovitch cycles ( i. e., eccentricity, obliquity and precession). The filtered long and short orbital eccentricity cycles show a good match with the La2010d astronomical target curve, allowing to create an independent time frame based on cyclostratigraphy. Our floating astronomical time scale provides new numerical age constraints for the Pinghu Formation, resulting in a total duration of ~4.95 Myr. A re-analysis of the available age data indicates that the sequence stratigraphic framework of the Pinghu Formation is best constrained to the early Oligocene, instead of the previously assumed late Eocene. Our study highlights that astronomical interpretation of sequence stratigraphic analyses is an excellent method to estimate the duration of sedimentary successions in boreholes and adds to a better understanding of the temporal and spatial sediment distribution patterns in the East China Sea Shelf Basin.

Pollen of middle Oligocene to early Miocene age from core sediments from the New Jersey Shallow Shelf (Atlantic Coastal Plain: IODP-Expedition 313, Site M0027A), was analyzed using light- and scanning electron microscopy, and a pollen-based bioclimatic analysis was performed. The microflora is dominated by Quercus pollen. Pollen ornamentations indicate that Quercus pollen most likely originated from species of sections Quercus, Lobatae, Quercus/Lobatae and aff. section Protobalanus. Eotrigonobalanus, an extinct Fagaceae lineage, was present in the coastal plain. Relative abundances of several tree taxa (e.g., Carya) did not change significantly between the Oligocene warm phases, but contrast to late middle Miocene (comprising most of the Langhian and Serravallian) records from the same area. By assigning terrestrial palynomorphs to paleovegetation units, topographic movements of these units were identified. The mesophytic forest was the most widespread and zonal vegetation type in the hinterland through the analyzed interval. Periodic changes in the relative abundances of paleovegetation units suggest altitudinal vegetation movements responding to global climate change. Observed movement signals are generally weak, but increases in bisaccate pollen, representing spread of high- and mid-latitude forest, probably reflect the onset of cold intervals such as cooling phases at ~ 29.1, ~ 28.5, and 23.5 Ma. Spread of edaphically controlled forest formations during regression phases also indicates climate change. The onset of the Mi-1 event at ~ 23.03 Ma is probably reflected by a decrease in pollen-inferred paleotemperatures, although the event itself occurred during a sedimentation hiatus. Pollen-based paleoclimate reconstructions indicate long-term stability in temperature and precipitation within the humid warm temperate zone.

Two new late Oligocene species of Deperetomys: D. calefactus and D. saltensis, are described and the affinities between the various species are discussed. The new records extend the stratigraphic range of Deperetomys into the Oligocene, making it the first European Miocene murid that can be traced across the “Cricetid vacuum”. A single M1 of a large early Oligocene murid that may represent the oldest record of Deperetomys is described. The classification problems that arise as a result of the fast increase of information of the Paleogene Muridae from Asia and the Middle East are addressed and the need to recognise and define clades above the genus level is demonstrated. Our conclusion is that the Deperetomys clade contains at least three different evolutionary lineages.

The fossil otolith-based sciaenid genus Equetulus is known almost exclusively from South America, the Caribbean, and Central America, with the various species ranging in age from the late Oligocene to late Miocene. The only exception to this geographical distribution is the isolated occurrence of Equetulus silverdalensis n. comb. in the Belgrade Formation (latest Oligocene–early Miocene) in the Atlantic Coastal Plain of the USA (North Carolina) and a mention of its occurrence in the Chickasawhay Limestone (late Oligocene) in the Gulf Coastal Plain of the USA (Mississippi). However, sampling of the Paynes Hammock Sand (late Oligocene, Chattian) near Millry, Alabama, USA, resulted in the discovery of an otolith representing the first occurrence of E. silverdalensis in Alabama and the first systematic description of the species from the Gulf Coastal Plain of the USA. These occurrences suggest a potential distribution of this fossil species from Atlantic Coastal Plain of North Carolina to the central Gulf Coastal Plain of Alabama and possibly Mississippi.

Thirteen fossiliferous limestone deposits from Cenozoic strata in the Talara Basin in northern Peru are identified as ancient methane-seep deposits. Planktonic foraminifera and the existing stratigraphical framework of the Talara Basin indicate an early Oligocene, or possibly late Eocene, age of these deposits. They are found in three distinct areas - Belen, Cerro La Salina and Cerros El Pelado - and differ in their petrography, stable isotope signatures, and lipid biomarker and macrofaunal contents. At Belen, the carbon stable isotope signature of the carbonate and the abundance of n-alkanes indicates the possibility of oil seepage in addition to methane seepage; for Belen and Cerro La Salina the high abundance of the biomarker crocetane indicates a dominance of anaerobic methane-oxidizing archaea of the ANME-2 group, whereas the rather small combined crocetane/phytane peak of a Cerros El Pelado limestone agrees with mixed ANME-1/ANME-2 input. The macrofauna consists mainly of molluscs; the Cerro La Salina sites include mostly infaunal thyasirid and lucinid bivalves and only few vesicomyid bivalves; gastropods include Provanna antiqua, the limpet Pyropelta and several vetigastropods. The Belen site is dominated by the elongate vesicomyid bivalve Pleurophopsis lithophagoides. The most common bivalve at the Cerros El Pelado sites is an undetermined, possible vesicomyid, and a smooth provannid gastropod. Biogeographically the faunas are most similar to those of the northwestern United States, as indicated by two joint species; similarities on the genus level (Conchocele, Lucinoma, Pleurophopsis, Provanna, Colus) exist also with Japan and the Caribbean region.

The fossil otolith-based sciaenid genus Equetulus is known almost exclusively from South America, the Caribbean, and Central America, with the various species ranging in age from the late Oligocene to late Miocene. The only exception to this geographical distribution is the isolated occurrence of Equetulus silverdalensis n. comb. in the Belgrade Formation (latest Oligocene–early Miocene) in the Atlantic Coastal Plain of the USA (North Carolina) and a mention of its occurrence in the Chickasawhay Limestone (late Oligocene) in the Gulf Coastal Plain of the USA (Mississippi). However, sampling of the Paynes Hammock Sand (late Oligocene, Chattian) near Millry, Alabama, USA, resulted in the discovery of an otolith representing the first occurrence of E. silverdalensis in Alabama and the first systematic description of the species from the Gulf Coastal Plain of the USA. These occurrences suggest a potential distribution of this fossil species from Atlantic Coastal Plain of North Carolina to the central Gulf Coastal Plain of Alabama and possibly Mississippi.

A tooth of Physogaleus aff. contortus (Gibbes, 1849) was found in the Oligocene (Early to Middle Rupelian) Boom Clay Formation in the Swenden-Wienerberger quarry in Rumst, Belgium on the 16th of November 2019. This is the second specimen of this species known to have been found in the Boom Clay Formation. The first one was described by Storms (1894).

Two species of Witenia and a new pappocricetodontine genus and species from the late Eocene and early Oligocene of south-east Serbia are described. The Pappocricetodontinae a subfamily originally based on the small Pappocricetodon rencunensis from China has become a polyphyletic entity due to inclusion of the genus Witenia. The dental morphology of the late Eocene Witenia europea nov. sp. is very similar to that of the middle Eocene Pappocricetodon antiquus, but its molar enamel is more primitive. The small Bustrania dissimile nov. gen. nov. sp., the dominant species in the late Eocene locality of Buštranje, is defined and allocated to the Pappocricetodontinae.

The Rupelian Uromieh section of the Qom Formation consists of Nummulites-bearing limestones that overlay thick polymictic conglomerates and are overlaid by marlstones rich in planktonic foraminifera. The section was analyzed with the aim to provide a first description of its still unknown coralline algal assemblages, and for depicting its benthic paleoecological evolution through time. The early to middle Rupelian age has been constrained by the occurrence of Nummulites fichteli Michelotti, Nummulites vascus Joly & Leymerie, Halkyardia maxima Cimerman and Subterraniphyllum thomasii Elliot, along with the absence of Nephrolepidina Douvillé and Eulepidina Douvillé. A proximal inner-platform environment is reconstructed for the lower part of the section, based on the abundance of miliolids and corals, while upsection the increase in large rotaliids, coralline algae and bryozoans points toward a distal inner-platform/proximal middle-platform setting. Coralline algal assemblages support this interpretation, with Sporolithales and Hapalidiales becoming more common in the upper part of the section. Within the coralline assemblage, Lithoporella melobesioides Foslie and Titanoderma pustulatum (Lamouroux) Nägeli are two of the most common species, together with articulated coralline algae. Among the latter, S. thomasii is more common in coral-rich intervals. The specimens of T. pustulatum recovered in the Uromieh section predate all the other known records of this species, indicating that the origin of T. pustulatum should be dated at least at the early Rupelian.

The pteropod species Limacina ernstkittli Janssen, 2012, described from the Chattian (Late Oligocene) of northern Germany and Malta, is recorded from euryhaline deposits of Rupelian (Early Oligocene) age in Belgium. Its occurrence in near coastal, not fully marine assemblages, anticipating earlier records with at least 5 mA, is surprising. Critical notes are provided regarding the introduction of the name Borgloon Formation in 1988 without the designation of a type locality / type section; we recommend to replace it by the name Atuatuca Formation which was coined in 1976 and being accompanied by a fully described type locality and type section.

Pelagic sediments from the subtropical South Atlantic Ocean contain geographically extensive Oligocene ooze and chalk layers that consist almost entirely of the calcareous nannofossil Braarudosphaera. Poor recovery and the lack of precise dating of these horizons in previous studies has limited the understanding of the number of acmes, their timing and durations, and therefore their likely cause. Here we present a high-resolution, astronomically tuned stratigraphy of Braarudosphaera oozes (29.5–27.9 Ma) from Ocean Drilling Program Site 1264 in the southeastern Atlantic Ocean. We identify seven episodes with highly abundant Braarudosphaera. Four of these acme events coincide with maxima and three with minima in the ~110 and 405-kyr paced eccentricity cycles. The longest lasting acme event corresponds to a pronounced minimum in the ~2.4-Myr eccentricity cycle. In the modern ocean, Braarudosphaera occurrences are limited to shallow marine and neritic settings, and the calcified coccospheres of Braarudosphaera are probably produced during a resting stage in the algal life cycle. Therefore, we hypothesize that the Oligocene acmes point to extensive and episodic (hyper) stratified surface water conditions, with a shallow pycnocline that may have served as a virtual seafloor and (partially/temporarily) prevented the coccospheres from sinking in the pelagic realm. We speculate that hyperstratification was either extended across large areas of the South Atlantic basin, through the formation of relatively hyposaline surface waters, or eddy contained through strong isopycnals at the base of eddies. Astronomical forcing of atmospheric and/or oceanic circulation could have triggered these conditions through either sustained rainfall over the open ocean and adjacent land masses or increased Agulhas Leakage.

A new diatomyid genus and species, Inopinatia balkanica, from the early Oligocene of south-east Serbia is described, and the affinities between the Diatomyidae and Ctenodactylidae are discussed. Inopinatia balkanica nov. gen. nov. sp. seems to have retained its deciduous teeth throughout life just as all other species of the family. The only other diatomyid described from outside south-east Asia which is Pierremus explorator López-Antoñanzas, 2010 is transferred to the thryonomyid species Paraphiomys knolli.

Seven new rodent faunas are described from the Pčinja and Babušnica-Koritnica basins of south-east Serbia. The geology of the Tertiary deposits in the Pčinja and Koritnica-Babušnica basins of south-east Serbia is briefly reviewed. The fossil content of the new vertebrate localities is listed, and an inventory of the rodent associations is presented. The rodent associations are late Eocene-early Oligocene in age, interpreted on biostratigraphical grounds. These are the first rodent faunas of that age from the Balkan area, an important palaeogeographic location between Europe and Asia. The Muridae, with the subfamilies Pseudocricetodontinae, Paracricetodontinae, Pappocricetodontinae, Melissiodontinae and ?Spalacinae, are dominant with eight genera, four of which are new. The diversity of the Melissiodontinae and Paracricetodontinae in the faunas suggests that these subfamilies originated in this region. The bi-lophodont cheek teeth occurring in the Oligocene assemblages are identified as the first record of the Diatomyidae outside of Asia. In light of the large amount of new data, the palaeogeographic setting and faunal turnover of the Eocene-Oligocene is discussed.

The dental pattern of Yindirtemys deflexus from Mongolia has been analysed using a Micro-CT scanner. This ctenodactylid exhibits a peculiar dental pattern, characterised by a mesodont dentition with some degree of selenodonty, an intricate enamel folding and elevated connections between cusps. Furthermore, the wear sequence in the upper tooth row shows very worn M1 even before other teeth emerge. The descriptive parameters used in the analyses (Area, Perimeter and structural density) allowed us to determine the relative wear stage in the different dental elements. The study reveals for Yindirtemys deflexus a wear pattern typical of mesodont teeth in which the maximum perimeter of the enamel is relatively constant over a large part of the crown height, and the Structural density decreases progressively until the senescence of the tooth. This peculiar dental morphology and eruption sequence of Y. deflexus is interpreted as the result of the evolution towards a relatively more durable dentition caused by the adaptation to more arid environments.

Knowledge on lower tetrapods from the Palaeogene of Romania is rather scanty even if some of the fossil vertebrate localities were known for more than a century. Here we report a diverse fossil assemblage of lower tetrapods (salamanders, frogs, lizards, snakes and crocodylians) from the early Oligocene localities of Suceag and Cluj-Napoca (Rupelian, MP 23/24; Dâncu Formation, Romania). Among salamanders, the proteid Mioproteus sp., may represent a new taxon and the first fossil record of a proteid from the Cenozoic of Europe. Rare remains of the alytid frog Latonia and the ranid frog Pelophylax may correspond to one of the earliest fossil records from the European Palaeogene, while the palaeobatrachid Albionbatrachus oligocenicus may be considered a survivor of the Eocene/Oligocene extinction event. The amphibian assemblage probably preferred fluvial and/or marshy-lacustrine paleoenvironments. In the studied localities, the taxa inhabiting terrestrial ecosystems are relatively rare [the anguid lizard Ophisaurus sp., the small-sized snakes Eoanilius sp. (Aniliidae) and “Tropidophiidae” indet (Boidea)] and probably these forms inhabited the areas with azonal vegetation surrounding the rivers and wetlands. The palaeoclimate was relatively temperate, as it is suggested by the presence of Diplocynodon (mean annual temperature at least of 14.50 C, or even higher). The assemblage as a whole documents the existence of terrestrial corridors and suggest important zoogeographic connections (e.g. link with N-America is suggested by the presence of proteids, whereas that with former Gondwana by the ranid frogs).

As multistressors have been shown to have significant effects on biodiversity and ecosystem functioning, the following study was made with the purpose of examining how a number of stressors specifically connected to climate change may have varied during the latest 65,5 million years and whether it is possible to predict potential effects on global biodiversity in the future. The analyses focused on global species richness during the Cenozoic age along with variables such as variations in atmospheric CO2, sea surface temperatures and global sea levels derived from analyses of various stable isotopes found in marine sediments. The results were primarily based on a Pearson Correlation Test and a One-Sample T-test, including data from Fossilworks.org and from an empirical literature study. Two of the variables, sea surface temperature and global sea level, had a significant relationship to global species richness. Variations in atmospheric CO2 were non-significant to species richness. The results suggest that multistressors related to various tectonic events, here expressed as changes in the oceanic circulation and the global mean temperature as a result of tectonic movements of the continents over time, had a higher impact on global biodiversity compared to stressors induced by changes in concentrations of CO2 in the atmosphere during the Cenozoic age, based on the time-scale used in this study. However, given the fact that the time-scale used here was measured in millions of years rather than hundreds of thousands of years, those results might be slightly difficult to compare directly to similar effects in the present and thus predict potential future effects on global biodiversity. Based on those results, it is suggested that changes in concentrations of atmospheric CO2 over time result in stress-related short-term effects on global biodiversity compared to other stressors induced by tectonic activity, although the former may still have some potential to affect globa, Multipla stressfaktorer och deras inverkan på jordens biologiska mångfald under Kenozoikum Multipla stressfaktorer, inkluderat faktorer med anknytning till klimatförändringar, har länge påvisats ha stark inverkan på biologisk mångfald över tid. För att undersöka möjligheten att förutspå potentiella framtida effekter på den globala mångfalden genomfördes därför en studie med huvudsakligt fokus på hur jordens biologiska mångfald har varierat under den kenozoiska eran. Denna geologiska era är känd som den tid då däggdjuren började utvecklas efter dinosauriernas utdöende. Då så kallade multipla stressfaktorer har länge påvisats ha påtagliga effekter på levande organismer såväl som på hela ekosystem, gjordes i detta fall en studie med syftet att utreda hur stressfaktorer med specifika anknytningar till klimatförändringar har påverkat jordens biologiska mångfald mätt i antal arter under de senaste 65,5 miljoner åren, och huruvida om det är teoretiskt möjligt att förutse potentiella effekter på den biologiska mångfalden även i framtiden. Baserat på en serie analyser med det huvudsakliga syftet att undersöka hur stressfaktorer med dels anknytningar till förändringar i koldioxidhalterna i atmosfären och dels anknytningar till förändringar i jordens geofysiska egenskaper (här representerade av förändringar i jordens globala medeltemperatur och havsnivå i förhållande till idag) har påverkat den biologiska mångfalden över tid, visade det sig att medan stressfaktorer med anknytning till förändringar i koldioxidhalter i atmosfären tycks inte ha haft någon större märkbar påverkan på jordens biologiska mångfald under de senaste 65,5 miljoner åren, hade däremot stressfaktorer med anknytning till jordens geofysiska egenskaper märkbar påverkan på jordens artrikedom över tid. Även om samtliga erhållna resultat dock visade sig vara svåra att direkt jämföra med nuvarande förändringar i nutiden, och således försvårade möjligheten att förutse potentiella effekter även i framtiden; vidare b

A significant discrepancy of up to 0.6 Myr exists between radio-isotopically calibrated and astronomically tuned time scales of the late Eocene-Oligocene. We explore the possible causes of this discrepancy through the acquisition of “high-precision” 206Pb/238U dating of zircons from 11 volcanic ash beds from the Umbria-Marche sedimentary succession, which hosts the Global Stratotype Section and Point for the base of the Oligocene. Our results indicate that the four 40Ar/39Ar dates from the Umbria-Marche succession, which underpin the late Eocene-Oligocene portion of the Paleogene geomagnetic polarity time scale in the 2012 edition of the Geological Time Scale, are anomalously old by up to 0.5 Myr. Conversely, when integrated with the established magnetic polarity record of the Umbria-Marche succession, 206Pb/238U (zircon) data from this study result in Oligocene magnetic reversal ages that are generally equivalent to those obtained through the tuning of Ocean Drilling Program (ODP) Site 1218 (equatorial Pacific). Furthermore, our results indicate that the late Eocene tuning of ODP Site 1218, and International Ocean Discovery Program (IODP) Sites U1333–1334 (equatorial Pacific), to the 405 kyr eccentricity signal is accurate, at least back to 36 Ma. Propagating the full uncertainty of our radio-isotopic data set and, where appropriate, taking into account locally derived astronomical time scales, we arrive at an age of 34.09 ± 0.08 Ma for the Eocene-Oligocene boundary and 28.11 ± 0.17 Ma for the base of the Chattian.

The insectivore and marsupial assemblage from the Banovići Basin (MP30/MN1, Bosnia and Herzegovina) provides, in addition to the Rodentia, a better understanding of the faunal exchange between Europe and Anatolia and the biostratigraphic, paleoecological, and paleobiogeographic interpretations of the area. The small and rather poorly preserved collection of fossil remains of insectivores and marsupials from Banovići includes three genera of Talpidae, three genera of Soricidae, one genus of Erinaceidae, one genus of Heterosoricidae, and one marsupial. At the genus level, this assemblage is a mix of genera known from the late Oligocene–early Miocene of Europe (MP29–MN3) and Anatolia (~MP30–MN3). The presence of the talpids Suleimania aff. ruemkae and Desmanodon aff. ziegleri indicates an age within the Oligocene/Miocene boundary interval (MP30/MN1), which is consonant with the age estimate based on the rodents and magnetostratigraphy. The diversity of Soricidae and the presence of Geotrypus indicate that the Banovići biotope was rather warm and humid during the late Oligocene.

From the Alps in western Europe to the great steppes of Kazakhstan, the former Paratethys Sea once covered a vast area of our planet, of which the Black Sea, Caspian Sea and Aral lake are today’s remnants. The Paratethys formed as the Tethys ocean gradually closed, and was known as ‘Peri-Tethys’ until the late Eocene. The Peri-Tethys transformed into the Paratethys after it became an isolated basin from the Oligocene onwards. Initially, Laskarev (1924) coined the term Paratethys, describing the environment of Miocene sediments, containing peculiar fossils that developed in this isolated environment. Later, also Oligocene strata were included, which show the first isolation from the Tethys ocean. The birth of the Paratethys is characterised by a change in sedimentation reflecting well-oxygenated bottom waters during the Eocene, towards low-oxygen environments in the Oligocene (Maikop Series). In my thesis, we set out to unravel the roles of tectonic and eustatic mechanisms on the transition from Peri-Tethys to Paratethys and onset of oxygen-poor conditions. We focus on sections that show the change from the Eocene open configuration of the Peri-Tethys to the enclosed setting of the Paratethys, and on the progressively closing marine connections of the Paratethys. We investigate Maikop equivalent sediments in southern Germany (North Alpine Foreland basin; NAFB), and the Maikop and underlying sediments at its type section (Belaya river, Russia). My thesis covers millions of years, and a vast geographic area, to better understand the timing and paleogeographic changes in the basin. This large-scale approach has enabled us to shed light on many different aspects that were important for the evolution from Peri-Tethys to Paratethys. We show that the connection of the Paratethys trough the NAFB closes at 33.15 Ma, millions of years earlier than the previously estimated 28 Ma. In Russia, we show that oxygen-depleted episodes already occurred in the Kuma formation (mi

This study investigates the stratigraphic evolution of the Late Oligocene - Early Miocene carbonate platforms of the Yadana area (offshore Myanmar). Well data, regional 2D and local 3D seismic surveys allow the identification of three shallow-water carbonate platforms (Yadana, 3DF and 3DE) showing various morphologic and stratigraphic patterns influenced by the presence of a paleohigh. The identification of seven seismic sequences in the Yadana area constrains the stratigraphic evolution in three stages: (1) development of aggrading attached and isolated platforms during the Chattian; (2) a period of platform emersion during the Oligocene - Miocene transition; (3) drowning of the smaller buildup (3DE) associated with km-scale backstepping on the large platforms (3DF and Yadana) during the Aquitanian. The Aquitanian marks the onset of renewed volcanic activity associated with the development of fringing carbonate reefs during the Burdigalian. The rapid (∼6 My) development of these wide (∼5–70 km) and thick (∼300–850 m) carbonate platforms has been mainly controlled by the subsidence. However, the results highlight a strong overprint of eustatic fluctuations on the rates of change in accommodation, and hence on the stratigraphic architecture of the carbonate platforms. Based on an alternative model for the Cenozoic geodynamic evolution of the Yadana area, our results suggest that the platforms developed on a volcanic ridge of hotspot origin located in the Indian Ocean and not on a volcanic arc. Subduction jump processes are interpreted to have played a key role in the demise of all platforms by drastically changing the paleoenvironmental conditions during the Early Miocene, and led to the present-day location of the Yadana Ridge in a back-arc setting. The carbonate platforms from the Yadana area are thus a representative example of the interplay between global mechanisms and local paleoenvironmental parameters on carbonate platform initiation, growth and demise.

Purpose: Slope-associated ichnoassemblages show great variability according to the physiography of the platform-slope system, sedimentary taxa and nutrient input. Ophiomorpha rudis uses to be common in turbiditic successions, therefore its detailed characterization is essential for the understanding of this kind of deposits. Methods: Ichnological, stratigraphic and sedimentological analyses were carried out in Oligocene slope deposits in the Cala Piteres section (southeastern Spain), where exceptionally preserved Ophiomorpha rudis 3D-boxworks are present. Results: Four different sedimentary facies were recognized: (i) marls, (ii) tightly packed conglomerates, (iii) coarse-grained debrites with scattered clasts and olistoliths, (iv) gravity-flow induced calcarenites. The first facies was related to background sedimentation, while the other ones were considered to represent different gravity-flow deposits in slope channels. The ichnological analysis revealed the presence of two ichnoassemblages, dominated by Zoophycos isp. and Ophiomorpha rudis, respectively. The first ichnoassemblage developed in marls and presents Zoophycos together with Chondrites targionii and rare Rhizocorallium. The second one developed in the calcarenitic gravity-flow deposits, where Ophiomorpha exhibits complex mazes with horizontal burrows and vertical shafts. Conclusions: The horizontal development of Ophiomorpha on the upper surface of the beds would appear to follow organic matter distribution. On some bed surfaces, the cones representing the burrows entrance are preserved, this allowing for the estimation of the burrows penetration depth and for a detailed characterization of the colonization surface and of the whole burrow architecture. The study of the previously described ichnoassemblages let us consider the studied section as an expression of the Ophiomorpha rudis ichnosubfacies in an upper slope., Objetivos: Topografía, nutrientes y tasa de sedimentación son los parámetros que suelen determinar la variabilidad de las icnoasociaciones de plataforma-talud. La ubicuidad de Ophiomorpha rudis en entornos turbidíticos hace que su caracterización sea indispensable en la comprensión de dicha variabilidad. Métodos: Se realiza un estudio icnológico, estratigráfico y sedimentológico de detalle de la sección de Cala Piteres (Alicante, SE España), donde afloran ejemplos excepcionales de complejos de galerías de Ophiomorpha rudis. Resultados: Diferenciamos 4 facies sedimentarias, una de ellas (margas), corresponde a la sedimentación autóctona del talud, mientras que las tres restantes (brechas clasto-soportadas, debritas con olistolitos y calcarenitas) representan diferentes tipos de flujos gravitacionales. En este entorno, el análisis icnológico ha evidenciado la presencia de dos icnoasociaciones, la primera, desarrollada en los niveles margosos, dominada por Zoophycos reelaborados localmente por Chondrites targionii, y una segunda, típica de los niveles de calcarenitas turbidíticas, caracterizada por complejos retículos 3D de Ophiomorpha rudis. Conclusiones: Los conos de sedimento bioturbado que aparecen en el techo de varias turbiditas son reconocidos como la superficie original de colonización de la red de galerías de O. rudis. Esta circunstancia permite concluir que la distribución de materia orgánica, especialmente abundante a techo de la turbidita, es el mayor condicionante del desarrollo horizontal de las galerías. Además, permite una estimación más ajustada de la profundidad de las pistas y una reconstrucción detallada de su arquitectura. Por último, la alternancia de icnoasociaciones (Zoophycos/Ophiomorpha rudis), permite identificar la ichnosubfacies de O. rudis en la zona superior del talud, de transición a la icnofacies de Zoophycos.

This study investigates the stratigraphic evolution of the Late Oligocene - Early Miocene carbonate platforms of the Yadana area (offshore Myanmar). Well data, regional 2D and local 3D seismic surveys allow the identification of three shallow-water carbonate platforms (Yadana, 3DF and 3DE) showing various morphologic and stratigraphic patterns influenced by the presence of a paleohigh. The identification of seven seismic sequences in the Yadana area constrains the stratigraphic evolution in three stages: (1) development of aggrading attached and isolated platforms during the Chattian; (2) a period of platform emersion during the Oligocene - Miocene transition; (3) drowning of the smaller buildup (3DE) associated with km-scale backstepping on the large platforms (3DF and Yadana) during the Aquitanian. The Aquitanian marks the onset of renewed volcanic activity associated with the development of fringing carbonate reefs during the Burdigalian. The rapid (∼6 My) development of these wide (∼5–70 km) and thick (∼300–850 m) carbonate platforms has been mainly controlled by the subsidence. However, the results highlight a strong overprint of eustatic fluctuations on the rates of change in accommodation, and hence on the stratigraphic architecture of the carbonate platforms. Based on an alternative model for the Cenozoic geodynamic evolution of the Yadana area, our results suggest that the platforms developed on a volcanic ridge of hotspot origin located in the Indian Ocean and not on a volcanic arc. Subduction jump processes are interpreted to have played a key role in the demise of all platforms by drastically changing the paleoenvironmental conditions during the Early Miocene, and led to the present-day location of the Yadana Ridge in a back-arc setting. The carbonate platforms from the Yadana area are thus a representative example of the interplay between global mechanisms and local paleoenvironmental parameters on carbonate platform initiation, growth and demise.

This study investigates the stratigraphic evolution of the Late Oligocene - Early Miocene carbonate platforms of the Yadana area (offshore Myanmar). Well data, regional 2D and local 3D seismic surveys allow the identification of three shallow-water carbonate platforms (Yadana, 3DF and 3DE) showing various morphologic and stratigraphic patterns influenced by the presence of a paleohigh. The identification of seven seismic sequences in the Yadana area constrains the stratigraphic evolution in three stages: (1) development of aggrading attached and isolated platforms during the Chattian; (2) a period of platform emersion during the Oligocene - Miocene transition; (3) drowning of the smaller buildup (3DE) associated with km-scale backstepping on the large platforms (3DF and Yadana) during the Aquitanian. The Aquitanian marks the onset of renewed volcanic activity associated with the development of fringing carbonate reefs during the Burdigalian. The rapid (∼6 My) development of these wide (∼5–70 km) and thick (∼300–850 m) carbonate platforms has been mainly controlled by the subsidence. However, the results highlight a strong overprint of eustatic fluctuations on the rates of change in accommodation, and hence on the stratigraphic architecture of the carbonate platforms. Based on an alternative model for the Cenozoic geodynamic evolution of the Yadana area, our results suggest that the platforms developed on a volcanic ridge of hotspot origin located in the Indian Ocean and not on a volcanic arc. Subduction jump processes are interpreted to have played a key role in the demise of all platforms by drastically changing the paleoenvironmental conditions during the Early Miocene, and led to the present-day location of the Yadana Ridge in a back-arc setting. The carbonate platforms from the Yadana area are thus a representative example of the interplay between global mechanisms and local paleoenvironmental parameters on carbonate platform initiation, growth and demise.