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Crustal deformation and hydrothermal percolation related to the India‐Asia collision have caused extensive remagnetization of the Tethyan Himalaya Terrane (THT). The present work identified three phases of regional remagnetization during 62.3–50.0 Ma for the east‐central THT. Consequently, a model of three‐stage India‐Asia collision was proposed. The east‐central THT first collided with the southward migrated southern margin of the Lhasa Terrane (LT) at 5.4 ± 0.9°N during 62.3–60.9 Ma. Subsequently, the THT continuously moved northward and pushed the southern margin of the LT back to its original position prior to the initiation of fore‐arc and back‐arc extension on both sides of the Gangdese magmatic arc. Since the final suturing of the THT with Asia at ∼10°N during 59.8–58.0 Ma, the east‐central THT remained stationary until India collided with it at 10.9 ± 5.1°N at ∼50.0 Ma. Plain Language Summary: The collision of India and Asia caused intense tectonic deformation and hydrothermal alteration throughout the Tethyan Himalaya Terrane (THT), which resulted in the large‐scale remagnetization in the THT. The regional remagnetization of the THT can be used to constrain the India‐Asia collision process, on the premise that the time of remagnetization can be determined. Based on this assumption, we measured two representative Paleocene remagnetized components from Early Jurassic limestones in the Gyangze Basin in the east‐central THT. These remagnetized components, combined with non‐remagnetized components and remagnetization events recorded in the adjacent areas, suggest that the east‐central THT experienced three phases of regional remagnetization during 62.3–50.0 Ma. The first and second phases of remagnetization in the north‐central part of the east‐central THT occurred at the paleolatitude of 5.4 ± 0.9°N at 62.3–60.9 Ma and 10.3 ± 1.0°N–9.5 ± 1.1°N at 59.8–58.0 Ma, respectively. The third phase of remagnetization occurred in the southern part of the east‐central THT, at the paleolatitude of 10.9 ± 5.1°N at ∼50.0 Ma. Consequently, a model of three‐stage India‐Asia collision and southward spreading tectonic deformation of the THT was proposed based on these successive remagnetizations. Key Points: The east‐central Tethyan Himalaya Terrane (THT) experienced three phases of large‐scale remagnetization during 62.3–50.0 MaThe collision of THT with the Lhasa Terrane commenced at 62.3–60.9 Ma and finished at 59.8–58.5 MaIndia finally collided with the THT at the paleolatitude of ∼10.9 ± 5.1°N at ∼50.0 Ma [ABSTRACT FROM AUTHOR]

Microfaunal analysis of Cretaceous and Paleogene sediments collected over several decades from Western Siberia has illuminated the diversity, stratigraphic distribution, and paleoecological signifi cance of the rare low trochospiral benthic foraminiferal genus Bagginoides. Here, we describe two new species B. yamalensis n.sp. and B. tibeisalinella n.sp [ABSTRACT FROM AUTHOR]

Menispermaceae are an angiosperm family of mostly climbing plants distributed throughout tropical regions. The fruits in this family have a strong sclerified endocarp and can be used for reliable species‐level identifications, even in a fossilized form. New Paleocene‐age menispermaceous endocarps have recently been discovered in South America and Asia, while in Europe, they are mostly found in the Eocene. This paper focuses on the study of fossil endocarps belonging to Menispermaceae, found in the Petit‐Pâtis locality, which is one of the few Paleocene localities in Europe. The locality is dated to the late Paleocene (57–56 Ma) and the fossils represent flora and fauna in the Paris Basin before the onset of the Paleocene–Eocene Thermal Maximum. Lignitized fossils were photographed and their morphology was analyzed using computed tomography, scanning electron microscope, and geometric morphometric analysis. The analysis of 36 fossils belonging to Menispermaceae revealed that three genera (Stephania, Palaeosinomenium, Tinospora) were present in the late Paleocene of Paris Basin. Differences in internal morphology and a more inflated endocarp base led to a description of a new fossil species—Palaeosinomenium oisensis sp. nov. The occurrence of these genera in the Paleocene of France is consistent with the suggestion that megathermal flora was present in the Paris Basin before the Paleocene–Eocene Thermal Maximum. These three genera are currently the oldest occurrences in Europe, highlighting the connection between paleofloras of the Americas, Europe, and Asia in the Paleocene. [ABSTRACT FROM AUTHOR]

The post-collisional evolution of the Tibetan lithosphere is of paramount significance to our understanding of collisional orogeny. It is generally postulated that the Lhasa lithospheric mantle was horizontally shortened and thickened coherently with the overlying crust to form a physical barrier, preventing Indian subduction beneath Tibet until the thickened mantle root was foundered during the Miocene. This study first identifies post-collisional oceanic-island basalt (OIB)-type magmatism in the Lhasa Block (LB), as attested by zircon U-Pb age (ca. 58 Ma) and geochemistry--positive Nb-Ta anomalies, high La/Yb, and depleted bulkrock Sr-Nd and zircon Hf isotopes, of diabase in the northern (inboard relative to Indus Suture) part of this block. Coupled with extensive early Paleogene arc-type magmatism in the southern-central LB and thermodynamic modeling, we suggest that these diabases were formed by partially molten upwelling asthenosphere near the base of continental crust, where much of the underlying lithospheric mantle had been removed due to Neo-Tethyan slab rollback and lithospheric delamination. Compared to OIB-type magmatism worldwide, the diabases investigated here were emplaced peculiarly in a region where the continental crust was under horizontal compression and shortening by coeval thrusting. Our study thus implies a decoupled deformation between the crust and mantle of the LB during the early Indian-Asian collision. [ABSTRACT FROM AUTHOR]

We describe new macro- and microfossils recovered on a field expedition to the North Quarry of Poponguine, a locality in western Senegal that spans the Late Cretaceous through the Early Paleogene, albeit with a likely unconformity at the base of the Danian. Newly discovered macrovertebrates from the Maastrichtian Cap de Naze Formation include pycnodonts, dyrosaurids, and chelonians, the latter two the oldest and first Cretaceous representatives of these clades from Senegal. Screenwashing of this deposit revealed that the matrix also consists of abundant microscopic biological clasts comprising osteichthyan vertebrae, spines, and cranial fragments, shark dermal denticles, invertebrates, and numerous ovoid coprolites among other fragments. These microfossils document a much less conspicuous portion of the paleobiodiversity. We describe the stratigraphy of this new locality and incorporate it into a new correlated section that ties together three other Late Cretaceous–Early Paleogene fossiliferous localities of the Senegalese-Mauritanian Basin. The presence of fossiliferous Danian rocks, which are notably rare in West Africa, is elucidated in our section, which synthesizes prior geological and paleontological work around Poponguine and in the nearby coastal region of Ndayane. Primarily dated using the biostratigraphy of ostracods and foraminiferans, the correlated rock units include the Paki and the Cap de Naze Formations of the Late Cretaceous Diass Group and the Ndayane and the Poponguine Formations of the Paleocene Cap-Vert Group, deposits that capture ancient near shore marine environments. The localities described, although separated by only a few kilometers, exhibit dramatic differences in thickness across faulted blocks of the Diass Horst. Dyrosaurids, which are common fossils in nearshore marine outcrops of West Africa, have been hypothesized to be of African origin and to have dispersed to South America in the Late Cretaceous. This dyrosaurid specimen, although fragmentary, documents a western extreme in the geographic range of African dyrosaurids where the clade would have been well situated for broader trans-Atlantic dispersal. [ABSTRACT FROM AUTHOR]

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial lipids that have been widely used as environmental proxies in continental paleorecords. Another group of related lipids, branched glycerol monoalkyl glycerol tetraethers (brGMGTs), has recently been proposed as a potential paleotemperature proxy. Nevertheless, the sources and environmental dependencies of both brGDGTs and brGMGTs along the river–sea continuum are still poorly understood, complicating their application as paleoenvironmental proxies in some aquatic settings. In this study, the sources of brGDGTs and brGMGTs and the potential factors controlling their distributions are explored across the Seine River basin (NW France), which encompasses the freshwater-to-seawater continuum. BrGDGTs and brGMGTs were analyzed in soils, suspended particulate matter (SPM), and sediments (n=237) collected along the land–sea continuum of the Seine basin. Both types of compounds (i.e., brGDGTs and brGMGTs) are shown to be produced in situ, in freshwater and saltwater, based on their high concentrations and distinct distributions in aquatic settings (SPM and sediments) vs. soils. Redundancy analysis further shows that both salinity and nitrogen dominantly control the brGDGT distributions. Furthermore, the relative abundance of 6-methyl vs. that of 5-methyl brGDGTs (the IR 6Me ratio), the total nitrogen (TN), the δ15 N, and the chlorophyll a concentration co-vary in a specific geographical zone with low salinity, suggesting that 6-methyl brGDGTs are preferentially produced under low-salinity and high-productivity conditions. In contrast to brGDGTs, the brGMGT distribution appears to be primarily regulated by salinity, with a distinct influence on the individual homologues. Salinity is positively correlated with homologues H1020a and H1020b and negatively correlated with compounds H1020c and H1034b in SPM. This suggests that bacteria living in freshwater preferentially produce compounds H1020c and H1034b, whereas bacteria that primarily grow in saltwater appear to be predominantly responsible for the production of homologues H1020a and H1020b. Based on the abundance ratio of the freshwater-derived compounds (H1020c and H1034b) vs. their saltwater-derived homologues (H1020a and H1020b), a novel proxy, the Riverine IndeX (RIX), is proposed to trace riverine organic matter inputs, with high values (>0.5) indicating a higher riverine contribution. We successfully applied RIX to the Godavari River basin (India) and a paleorecord across the upper Paleocene and lower Eocene from the Arctic Coring Expedition at Lomonosov Ridge, showing its potential applicability to both modern samples and paleorecords. [ABSTRACT FROM AUTHOR]

The kinematics and deformation pattern along the Altyn Tagh fault (ATF), one of the largest strike‐slip faults on Earth is of great significance for understanding the growth of the Tibetan Plateau. However, the initial rupture along the ATF remains debated given the limited constraints on the depositional age of associated Cenozoic syntectonic strata. Here we investigated the syntectonic Cenozoic strata in the Xorkol Basin, associated with the strike‐slip faulting along the ATF. New uranium‐lead analyses of the carbonate deposits in the Paleogene strata yield dates of 58.9 ± 1.29 Ma, representing the initial rupture of the ATF. This first documented radioisotopic age coincides with the ca. 60 Ma onset timing of India‐Asia collision, highlighting its far‐field effect at the northern edge of the Tibetan Plateau. We infer that the deformation of the entire Tibetan Plateau started synchronously with the India‐Asia collision. Plain Language Summary: Carbonate U‐Pb dating techniques applied to rocks associated with the Altyn Tagh fault, a major fault in North Tibet, reveal that the fault started slipping about 58.9 million years ago, coinciding with the time when India collided with Asia. This finding provides new constraints on when and where this fault formed and suggests that the northern Tibetan Plateau started deformation earlier than previously thought. This result emphasizes that the entire Tibetan Plateau deformed simultaneously in the early Cenozoic. Key Points: Calcite U‐Pb dating yields ca. 59 Ma age for carbonate strata in the East Xorkol BasinXorkol Basin was a pull‐apart basin during the Paleocene due to the left‐lateral strike‐slip faulting along the Altyn Tagh faultWidespread Paleocene‐Eocene tectonism in Northern Tibet highlights the far‐field effect of the India‐Asia collision [ABSTRACT FROM AUTHOR]

The Arabia – Eurasia collision zone in the central part of the Alpine – Himalayan orogenic system has had a complex deformation history since the Palaeozoic. In Iran, the collision zone consists of the Alborz‐Talesh, Kopeh Dagh and Zagros foldbelts and the intervening Central Iran area. In this review paper, we summarize the structural architecture and tectonostratigraphic characteristics of these domains and attempt to correlate regional deformation events between them. The results show that six regional‐scale deformation phases can be recognized and correlated in Iran over a time interval extending from the Late Palaeozoic to the Late Cenozoic. Late Palaeozoic rifting in northern Gondwana and subsequent oceanic spreading resulted in the separation of the Central and North Iran blocks from the Arabian Platform. These blocks later converged and collided with the southern margin of Eurasia due to the subduction of the intervening PalaeoTethys lithosphere ("Cimmerian orogeny": Late Triassic). The convergent setting resulted in the initial development of the Alborz‐Talesh foldbelt in present‐day northern Iran, while extensional basins developed in the forebulge area in Central Iran. Continuing northward subduction of NeoTethyan oceanic lithosphere at the southern Eurasia margin produced Early Cretaceous back‐arc extension and associated volcanism in Central Iran and the Alborz‐Talesh area to the north. A phase of compressional deformation in the Late Cretaceous was related to the collision of a series of microcontinents derived from Northern Gondwana, including the Ercinjan and Bitlis massifs, with the Central Iran block, and is recorded in the Alborz‐Talesh foldbelt and in Central Iran. Further back‐arc extension in the late Paleocene – Eocene was accompanied by pervasive volcanism and volcaniclastic sedimentation throughout northern and Central Iran. The final closure of NeoTethys and convergence between the Arabian and Eurasian Plates evolved through phases of early Oligocene "soft" collision and middle Miocene "hard" collision. This was accompanied by thrusting in the internal parts of the Zagros foldbelt and by folding and subordinate thrusting in the more external parts, with related development of the flexural Mesopotamian Basin in the foreland to the SW. [ABSTRACT FROM AUTHOR]

The late Paleocene to early Eocene interval is characterized by a series of carbon perturbations that caused transient warming (hyperthermal) events, of which the Paleocene‐Eocene Thermal Maximum (PETM) was the largest. These hyperthermals can be recognized in the pelagic sedimentary record as paired negative δ13C and δ18O excursions, in addition to decreased calcium carbonate and increased iron content caused by carbonate dissolution. However, current data are predominantly sourced from the equatorial‐to subequatorial regions. Here we present a new high‐latitude late Paleocene—early Eocene record, recovered during International Ocean Discovery Program (IODP) Expedition 378 on the Campbell Plateau off New Zealand, in the southwest Pacific Ocean. To construct an age model, we correlated our chemostratigraphic and biostratigraphic data to existing astronomically‐tuned age models from Walvis Ridge (South Atlantic Ocean) and Demerara Rise (equatorial Atlantic Ocean). Our results indicate that the Site U1553 composite section spans ∼7 million years of the latest Paleocene to early Eocene (50.5–57.5 Ma), and preserves many of the early Eocene hyperthermals; including a PETM interval that is more expanded than elsewhere in this region. However, construction of the age model also revealed discrepancies between the chemostratigraphic and biostratigraphic tie points used for correlation. This is likely due to latitudinal diachroneity in the calcareous nannofossil biostratigraphic datums, which are primarily based on low‐to mid‐latitude assemblages. Therefore, our study highlights the need to establish a revised calcareous nannofossil biozonation that is more appropriate for high‐latitude age models. Key Points: A new chemostratigraphic age model (50.5–57.5 Ma) was developed for IODP Site U1553 in the high‐latitude South Pacific OceanCommonly used calcareous nannofossil datums show significant offsets at Site U1553 compared to records from lower latitude regionsThis study highlights the need to revise early Eocene calcareous nannofossil biostratigraphic datums to be applicable to high‐latitude sites [ABSTRACT FROM AUTHOR]

Premise of research. Macginitiea is an iconic and easily recognizable genus well known from the Paleogene of western North America and Kamchatka. Here we recognize new species and occurrences of Macginitiea from multiple sites in North America and discuss their implications for biogeography and evolution. Methodology. We studied leaves and inflorescences from multiple sites across North America. We used microcomputed tomography scans to illustrate the floret anatomy of Macginicarpa from Texas. Cuticles were examined using epifluorescence microscopy and maceration in Jeffrey's solution. Pivotal results. The distribution of Macginitiea suggests transberingial migration, similar to that in other platanoids like Platimeliphyllum. Macginitiea lived as far south as central Texas; few fossil platanoids are known from southern latitudes, even though most living Platanus species occur below 30°N. We document the cuticle anatomy of M. whitneyi , revealing a heavily striated cuticle with circular hair bases. Newly recognized species include those with a striking proclivity for basilaminar lobe development, including M. rannii sp. nov. from the Eocene of Wyoming, M. basilobata comb. nov. from the Paleocene of Montana, and M. rileyi comb. nov. from the Eocene of Texas and New Mexico. We also revise the taxonomy of Aralia wardiana (formerly Aralia digitata) and Platanus browni and show their affinities to Macginitiea. Using a broad concept of the gene regulatory networks governing lobe and stipule development, we hypothesize how different Macginitiea leaves could have developed their basilaminar lobes. Conclusions. We find that Macginitiea had a greater taxonomic diversity and a wider geographic range than was previously known. Among this diversity are several species with substantial basilaminar lobe development. Basilaminar lobes in modern and fossil platanoids tend to develop only when a leaf produces at or near the maximum number of lobes for that taxon. Influence of the same gene regulatory network may explain the similar appearance of stipules and basilaminar extensions in Platanaceae. [ABSTRACT FROM AUTHOR]

IODP Site U1509 (Expedition 371), New Caledonia Trough, provides a rare latest Cretaceous–Paleocene record from offshore northern Zealandia. We present new palynomorph and benthic foraminiferal assemblage data that show a transition from a latest Cretaceous vegetated sediment source region to a fully oceanic environment in the Paleocene. Latest Cretaceous (c. 68–66 Ma) non-calcareous claystone was deposited in upper bathyal paleodepths, with abundant plant microfossils that were likely transported in a northwest direction through the Aotea Basin region. A 2–3 Myr unconformity is identified at the Cretaceous/Paleogene boundary. Middle early–late Paleocene (c. 63.5–56 Ma) calcareous claystone shows evidence of deepening, deposited in middle bathyal or deeper paleodepths, and terrestrial input is minor. This latest Cretaceous to Paleocene deepening trend is consistent with inferred evolution of the Aotea and Northland basins further to the east, and other sparse northern Zealandia records, which show a common pattern of post-rift transgression consistent with long-term subsidence. Site U1509 allows for biogeographic extension and modification of the New Zealand Paleocene dinoflagellate zonation, description of a new dinoflagellate and pollen species, better inference of regional paleogeography, and may provide insights into the onset of western Pacific subduction initiation. [ABSTRACT FROM AUTHOR]

There are few studies focused on spore and pollen clumps in paleopalynological samples, and these are only reports from the Northern Hemisphere. These aggregates may be of animal or floral origin. The goal of this contribution is to provide the first detailed study of spore and pollen clumps from the Southern Hemisphere, and to discuss their possible origin, botanical affinities, and pollination modes, based on their morphological characteristics, preservation and comparison with putative living representatives. Three fern spore clumps and 18 angiosperm pollen clumps were recognized in Maastrichtian-Danian La Colonia Formation sediments that outcrop at Chubut Province, Patagonia, Argentina. Most clumps are monospecific and composed of undamaged elements but some of them have two types of spore/pollen with corroded and/or fragmented exines. These findings represent the most diverse and abundant record of fern and angiosperm clumps from the Late Cretaceous and early Paleocene so far known from South America and the Southern Hemisphere. These results are indicative of the need for comprehensive large-scale studies on pollination of modern taxa and careful processing of palynological samples to lessen the already large bias in paleopalynological interpretations. The paucity of information on clumps in the fossil record has impaired our comprehension of dispersion/pollination in deep time. [ABSTRACT FROM AUTHOR]

The Paleocene‐Eocene Thermal Maximum (PETM) and early Eocene hyperthermal events were characterized by a Hothouse climate state. Our understanding of the climatic impact of these hyperthermals is currently biased toward marine settings and the mid‐latitudes. Here we present organic geochemical data from Stenkul Fiord, Ellesmere Island, Arctic Canada. This organic rich formation was deposited in a high northern latitude wetland setting during the late Paleocene to early Eocene, spanning the PETM and subsequent ETM‐2 hyperthermals. Biomarker data (e.g., diterpenoids), combined with published palynological data from the site, indicate Cupressaceae‐dominated vegetation. Biomarkers suggest that land plant composition remained fairly unchanged across the two hyperthermal events. Increases in abundance and 13C‐depletion of hopanoid biomarkers (minima <−50‰ (VPDB)) highlight periods of enhanced bacterial methane consumption, particularly during the PETM. However, periods of low hopanoid δ13C values were also found outside the hyperthermal intervals. Relatively low δ2H values of higher plant n‐alkanes (average δ2H values of n‐C25, n‐C27, n‐C29 ∼ −230 to −270‰ (SMOW)) indicate that deposition formed during times with enhanced precipitation. The wettest intervals, as identified by the lowest δ2H n‐alkane values, contain high abundances of hopenes, indicating enhanced bacterial turnover. At Stenkul Fiord, high temperatures and CO2 concentrations likely fostered the growth of widespread wetland forests that became a CO2 sink and may have played an important role in carbon drawdown during the Early Paleogene. Key Points: First detailed biomarker study on high‐latitude terrestrial PETM settingBiomarkers and stable isotope signatures demonstrate cypress plant dominated setting with high methane cycling during hyperthermalsSwamp environment suggested and intense bacterial methane consumption not restricted to hyperthermals [ABSTRACT FROM AUTHOR]

Summary: The storied structure in wood anatomy is considered derived and highly specialized, and is present in some related families. The first records of this character are from the Cretaceous, but it is scarce in the Cretaceous and Paleocene, and apparently absent until the Eocene in the temperate Southern Hemisphere. Using standard methodology, we describe the anatomy of a fossil wood from the early Paleocene of Patagonia (Salamanca Formation). The fossil wood, assigned to a new genus and species Elizabethiaxylon patagonicum related to the Malvaceae, is characterized by its diffuse-porous wood, solitary vessels, simple perforation plates, apotracheal banded axial parenchyma, and mostly biseriate storied rays. The storied structure in this wood is one of the oldest records from Gondwana. [ABSTRACT FROM AUTHOR]

We studied at least part of Kuhnʼs original material of lizards from the Paleocene (~ MP 5) of the Walbeck locality in Germany. The collection was considered to be lost but is consistently discussed in the literature due to its importance. We restudied the type material of aff. Parasauromalus paleocenicus and aff. Glyptosaurus walbeckensis described by Kuhn in 1940. The former was originally allocated to Iguania, the latter to Anguimorpha, though later on these identifications were questioned by several authors. We show such a classification of both cannot be upheld. P. paleocenicus resembles the morphology of lacertids showing their presence in Europe already around MP 5. We consider the name P. paleocenicus as a nomen dubium. The material of aff. G. walbeckensis was later suggested to belong to Lacertidae and also considered as a potential amphisbaenian. Although it differs from modern amphisbaenians, it shares features with one supposed polyodontobaenid – Camptognathosaurus parisiensis. The Walbeck form is identical to this species. Since the Walbeck taxon was described in 1940, the principle of priority makes Camptognathosaurus parisiensis a junior synonym of the species erected by Kuhn. We propose a new combined name for this form, Camptognathosaurus walbeckensis comb. nov. The specimen figured by Kuhn is currently lost, thus we designate a neotype from Walbeck. However, this taxon differs significantly from Polyodontobaena and new data doubt the attribution of Camptognathosaurus to Amphisbaenia. This taxon is tentatively assigned here to Lacertidae, as further confirmed by phylogenetic analyses. Material of Scincoidea is also described. [ABSTRACT FROM AUTHOR]

The present study interprets the high resolution of the biostratigraphy across the Cretaceous/Paleogene (K/Pg) boundary from Sulaymaniyah, Kurdistan Region, and north-east Iraq, based on planktic foraminifera. The Dartw section was selected for this study, within the High Folded Zone. The biozone contact consists of lithostratigraphic resemblance and is represented by the upper part of the Tanjero Formation (late Maastrichtian) with the overlying Kolosh Formation (Danian). Four late Maastrichtian planktic foraminiferal biozones have been recorded from the Tanjero Formation: Racemiguembelina fructicosa Interval Zone (CF4), Pseudoguembelina hariaensis Concurrent Range Zone (CF3), Pseudoguembelina palpebra Partial Range Zone (CF2), and Plummerita hantkeninoides Total Range Zone (CF1), while three Danian planktic foraminiferal biozones and two subzones have been recorded from the Kolosh Formation: (Guembelitria cretacea (P0) Interval Zone, Parvularugoglobigerina eugubina (Pα) Total Range Zone, and Parasubbotina pseudobulloides (P1) Partial-Range Zone (Globoanomalina archaeocompressa (P1a) Partial Range Subzone, and Subbotina triloculinoides (P1b) Interval Subzone). High biostratigraphic resolution indicates a complete K/Pg transition with no hiatus at the studied section in the Sulaymaniyah area. The ranges of the species recognized in this study are given. Correlations with other sections in Iraq and other parts of the world, including the type Maastrichtian and Danian areas, are discussed and represented in correlation charts, together with the ranges of the important Upper Maastrichtian and Paleocene species. [ABSTRACT FROM AUTHOR]

The International Ocean Discovery Program (IODP) Expedition 396 to the mid-Norwegian margin recovered > 1300 m of pristinely preserved, volcanic-ash-rich sediments deposited during the late Paleocene and early Eocene from close to the centre of the North Atlantic Igneous Province (NAIP). Remarkably, many of these cores contain glendonites, pseudomorphs after the purported cold-water mineral ikaite, from sediments dated to the late Paleocene and early Eocene. These time intervals span some of the hottest climates of the Cenozoic, including the Paleocene–Eocene Thermal Maximum (PETM). Global deep-ocean temperatures are not thought to have dropped below 10 ∘ C at any point during this time, making the occurrence of supposedly cold-water (near-freezing temperature) glendonite pseudomorphs seemingly paradoxical. This study presents a detailed sedimentological, geochemical, and microscopic study of the IODP Exp. 396 glendonites and presents an updated model for the ikaite-to-calcite transformation for these glendonites. Specifically, we show that early diagenesis of basaltic ashes of the NAIP appear to have chemically promoted ikaite growth in the sediments in this region. Together with existing knowledge of late Paleocene and early Eocene glendonites from Svalbard to the north and early Eocene glendonites from Denmark to the south, these new glendonite finds possibly imply episodic, short-duration, and likely localized cooling in the Nordic Seas region, which may have been directly or indirectly linked to the emplacement of the NAIP. [ABSTRACT FROM AUTHOR]

Changes in fire ecology during warm and cold periods in the geological past are important because of their effects on terrestrial ecosystems and the global carbon cycle. We examined the charcoal concentrations of the Erden Obo section in Inner Mongolia to reconstruct the evolution of wildfire and their relationship to the regional vegetation from the Late Paleocene through Early Oligocene. Our data show that fire frequency were relatively high from the end of the Paleocene to the beginning of the Eocene, in accord with other paleofire records worldwide. However, low fire frequency occurred during the Early Eocene Climate Optimum (EECO), coincident with the change in the regional vegetation from shrubland to forest due to the strengthening of the regional rainfall, and we suggest that the humid climate may have been responsible for this decrease. High frequency fire occurred after the Middle Eocene, near-synchronously with the transition ofthe regional vegetation from forest to steppe. The high-frequency fire was most likely triggered by regional drought during the aridification process after the Middle Eocene. We propose that these temporal changes in the fire ecology were consistent within the northern temperate zone from the Late Paleocene through Early Oligocene, and we suggest that studies of global wildfires need to be evaluated within the context of paleovegetation zones and ecosystem evolution. [ABSTRACT FROM AUTHOR]

This paper discusses the current state of knowledge of Paleogene stratigraphy of Kaliningrad Oblast, the age of local stratigraphic units and the duration of possible gaps in deposition and proposes trends for future regional Paleogene stratigraphy. The Paleocene Chistoozerskaya and Lubava formations in total probably correspond to the Danian–Selandian on the basis of foraminiferal zonation, but their relationship is not entirely clear. The Zaostrovskaya Formation probably corresponds to the upper Thanetian, but its fossil record is very poor. The Sambian Formation corresponds to the Ypresian according to foraminifera, but its precise stratigraphical interval remains insufficiently substantiated. The Alka Formation is presumably late Lutetian–early Bartonian. The age of the Prussian Formation is emended based on dinocysts as early–late Priabonian, while the Palvé Formation is now dated as the latest Priabonian. The Kurshskaya Formation corresponds to the uppermost Eocene–Oligocene–?lower Miocene. The problem of the recognition and duration of hiatuses between formations remains relevant. [ABSTRACT FROM AUTHOR]

To better understand the effect of the Paleocene‐Eocene Thermal Maximum (PETM) on continental ecosystems, we studied 40 new palynological samples from the Bighorn Basin (BHB), northwestern Wyoming, USA. We see palm and fern abundances increase in the last 20–40 ka of the Paleocene, then dramatically with the onset of the carbon isotope excursion (CIE) defining the base of the PETM. Palynomorphs of plant groups with modern temperate climate distributions are absent from the CIE body, and this is when tropical plants are most diverse and abundant. During the CIE recovery, pollen of mesophytic/wetland plants become more common while tropical taxa persist. In the post‐CIE early Eocene tropical taxa are rare and temperate forms abundant, similar to the late but not latest Paleocene. Changes in the palynoflora are more easily detected if reworked palynomorphs are removed from analyses. We interpret palynofloral changes to indicate warming in the latest Paleocene, rapid warming and drying with the CIE onset, dry tropical climates through the CIE body, a return to wetter floodplains during a very warm CIE recovery, and cooler wet conditions in the post‐PETM early Eocene. These inferences are consistent with geochemical and paleobotanical proxies. Strikingly similar patterns in the palynoflora and megaflora suggest changes in vegetation were a basin‐wide phenomenon. These rapid, climatically forced changes in floral composition occurred without major extinction, perhaps indicating nearby refugia in which plants adapted to cooler and wetter climates persisted through the PETM. Key Points: Bighorn Basin palynofloras began shifting toward hot/dry tolerant plants during the latest Paleocene "pre‐onset" carbon isotope excursionsPalynofloras from early in the carbon isotope excursion (CIE)‐body were dominated by ferns and palms indicating disturbance, then later by dry tropical lineagesWetland taxa regained abundance during the CIE recovery, indicating climate‐forced changes in plant distributions without major extinction [ABSTRACT FROM AUTHOR]

Premise of research. Burseraceae is represented by a large number of fossils from the Cenozoic sedimentary succession and has a disjunct distribution today in the southern part of North America, Africa, Europe, and Asia. However, the family has a poor fossil record in deep time, making hypotheses concerning its origin and dispersal difficult to evaluate. Here, we report the occurrence of reproductive organs (fruit and flower) attributable to modern Burseraceae from the probable latest Maastrichtian (Late Cretaceous) to earliest Danian (early Paleocene) sediments of the Mandla Lobe of the Deccan Intertrappean beds of Madhya Pradesh, Central India. Methodology. X-ray micro–computed tomography was used to observe three-dimensional structures. The reconstruction software takes the 2D projection images acquired by the X-ray detector and generates a 3D image represented by gray values distributed in a volumetric space. The present fruit and flower fossils are identified through morphological comparison with another fossil and extant Burseraceae. Pivotal results. The fossil pyrene corresponds in morphology with that of Burseraceae (particularly some genera of Protieae and Bursereae), while the fossil flower, with the pentamerous organization of sepals and petals and ovary and 10 stamens arranged in two whorls around a prominent intrastaminal nectary disk, is particularly similar to Protium. The fossil fruit is here described as a new species of the fossil genus Bursericarpum Reid et Chandler as Bursericarpum indicum Kumar, Manchester et Khan sp. nov. and the fossil flower as Debursera indica Kumar, Manchester, Judd et Khan sp. nov. Conclusions. The present discoveries represent the oldest reliable fossil records of Burseraceae supporting its Gondwanan origin. These fossils also provide important information for tracing possible migration pathways of Burseraceae from India to Europe after the docking of the Indian subcontinent with Eurasia during the early Eocene (55 ± 10 Ma), supporting an "out-of-India" dispersal hypothesis. Based on earlier and present records we suggest that the family might have reached Europe from India and then colonized North America (during the Eocene) in areas where it is now regionally extinct. [ABSTRACT FROM AUTHOR]

The early Paleocene (Danian) Barentsburg flora from the Firkanten Formation, Svalbard, provides a valuable insight into the environment and climate of the Arctic early in the warm Palaeogene prior to the Paleocene–Eocene Thermal Maximum (PETM) event. The flora includes c. 50 species of ferns, ginkgos, conifers and angiosperms. Angiosperms predominate and are represented by the families Platanaceae, Cercidiphyllaceae, Trochodendraceae, Hamamelidaceae, Fagaceae, Betulaceae, Nyssaceae and several taxa of uncertain taxonomic position. Palaeoclimate parameters, calculated using a new calibration of the Climate Leaf Analysis Multivariate Program (CLAMP), indicate that Svalbard in the early Paleocene was characterized by a temperate, maritime, humid, seasonal climate with cool mild winters and warm summers. Humidity was highest during winter months. Short‐term winter snow cover and light frosts were likely to have been frequent. The CLAMP analysis yields a mean annual temperature of 10.1 ± 1.98°С, a warmest month mean temperature of 19.2 ± 2.49°C and a coldest month mean temperature of 1.7 ± 3.24°С. The growing season lasted c. 6 months. Precipitation during this growth period was 572.4 ± 296.50 mm, while vapour pressure deficit and potential evapotranspiration indicate very high humidity year‐round, with summer being only slightly drier than winter. Taken together with data from other early Paleocene circum‐Arctic sites, these results point to highly uniform, temperate and extremely humid conditions around the margins of the early Cenozoic Arctic Ocean. This condition represents the warm background condition that dominated in the Arctic prior to the anomalous extreme warmth of the early Eocene. [ABSTRACT FROM AUTHOR]

We here report on the first lizard fossils from the Deccan intertrappean strata (latest Cretaceous/Palaeocene) exposed at Kesavi, District Dhar in the Malwa Plateau of lower Narmada Valley, central India. The material is only fragmentary, but tentatively three tooth morphotypes of non-acrodontan lizards can be identified. Besides these, two oblong osteoderms, resembling paramacellodid osteoderms, are described as Squamata indet. The 4th isolated tooth is questionably referred to Squamata. Although the intertrappean deposits of the Deccan volcanic province have been explored for over three decades, lizards are scarce and many aspects remain unclear. However, the tentative absence of agamids in Kesavi and other localities yielding pre-Eocene deposits (e.g., Naskal and Kisalpuri) appears to be interesting, because a high diversity of agamids has been reported from early Eocene localities of India. There is, in contrast, a total absence of non-acrodontan lizards. The contrast between pre-Eocene and Eocene localities seems to be puzzling in the context of India's supposed physical isolation from Asia during this time. Only future researches can shed light on that. Although the material described here brings only limited new insight, it supports that non-acrodontan lizards were present in India during the latest Cretaceous/earliest Palaeocene. [ABSTRACT FROM AUTHOR]

A new concept of the formation of glauconite from the Paleocene deposits of the sedimentary cover of the southwestern part of the Near-Volga monocline is presented. It was formed as a result of halmyrolysis of ash material in lake conditions. Glauconitization is confined to the Paleogene thermal maximum and the periphery of active volcanism along the entire mobile belt. In this connection, it is widely distributed in the Paleogene deposits. Structural and crystal-chemical features of glauconite, stages of crystallization of its aggregates, paragenetic associations with smectite, kaolinite, and zeolite, as well as the presence of ore minerals indicate its authigenic origin. The authigenic origin is confined to the formations of temporary, episodically submerging shallow marine basins. An applied scheme of discrimination of glauconites by their crystallochemical features has been developed. The discrimination diagram can be used to determine the specific conditions of the sedimentation basin, which are expressed in the progradation cycles of glauconite accumulation. The cycles were controlled by induced depressions within the Russian plate. [ABSTRACT FROM AUTHOR]

The Dinaric–Hellenic mountain belt bends where two fault systems transect the orogen: (1) the dextral Shkoder-Peja Transfer Zone (SPTZ), active sometime between the Late Cretaceous and middle Eocene; (2) the Shkoder-Peja Normal Fault (SPNF), which accommodated NW–SE directed orogen-parallel extension. The SPTZ dextrally offsets the Dinaric–Hellenic nappes by ~ 75 km, a displacement attributed to reactivation of an Early Mesozoic rift transfer zone in the Adriatic margin during Paleogene subduction of the Pindos Ocean. This subduction involved an initial counter-clockwise rotation of the Hellenides with respect to the Dinarides around a pole at the NW end of the Budva–Krasta–Cukali–Pindos Basin. The SPNF overprints the SPTZ and is a composite structure comprising five fault segments: four of them (Cukali–Tropoja, Decani, Rožaje, Istog) were active under ductile-to-brittle conditions. They downthrow the West Vardar Ophiolite in the hanging wall. The Cukali–Tropoja and Decani segments exhume domes with anchizonal-to-greenschist-facies metamorphism in their footwalls. These structures formed during a first-phase of extension and clockwise rotation, whose Paleocene age is constrained by cross-cutting relationships. A second extensional phase was accommodated mainly by the fifth (Dukagjini) segment of the SPNF, a subsurface normal fault bordering syn-rift, mid-late Miocene clastic and lacustrine sediments in the Dukagjini Basin (DB) that are sealed by Plio-Pleistocene strata. This later phase involved subsidence of Neogene basins at the Dinaric–Hellenic junction coupled with accelerated clockwise oroclinal bending. The driving force for clockwise rotation is thought to be bending and rollback of the untorn part of the Adriatic slab beneath the Hellenides. [ABSTRACT FROM AUTHOR]

The International Ocean Discovery Program (IODP) Expedition 396 to the mid-Norwegian margin recovered >1300 m of pristinely preserved, volcanic ash-rich sediments deposited during the late Paleocene and early Eocene, from close to the centre of the North Atlantic Igneous Province (NAIP). Remarkably, many of these cores contain glendonites, pseudomorphs after the purported cold-water mineral ikaite, from sediments dated to the late Paleocene, Paleocene – Eocene boundary and early Eocene. These time intervals span some of the hottest climates of the Cenozoic, including the Paleocene-Eocene Thermal Maximum (PETM). Global deep ocean temperatures are not thought to have dropped below 10 °C at any point during this time, making the occurrence of supposedly cold-water (near-freezing temperature) glendonite pseudomorphs seemingly paradoxical. This study presents a detailed sedimentological, geochemical, and microscopic study of the Exp. 396 glendonites, and presents an updated model for the ikaite-to-calcite transformation for these glendonites. Specifically, we show that early diagenesis of basaltic ashes of the NAIP appear to have chemically promoted ikaite growth in the sediments in this region. Together with existing knowledge of late Paleocene and early Eocene glendonites from Svalbard to the north, and early Eocene glendonites from Denmark to the south, these new glendonite finds possibly imply episodic, short-duration, and likely localised cooling in the Nordic Seas region, which may have been directly or indirectly linked to the emplacement of the NAIP. [ABSTRACT FROM AUTHOR]

Materials on the Paleogene biostratigraphy of the Lomonosov Ridge in the Arctic Ocean are presented, including new data on foraminifera from the M0004A borehole section (interval 390–391 m) in its polar part. The studied benthic foraminifers are united into the complex with Reticulophragmium coksuvorovae of the upper part of the Selandian Stage to the lower part of the Thanetian Stage, which includes some characteristic species of the North Atlantic and West Siberian basins. Also, information about the connection of these Arctic seas in the Paleocene time is presented. [ABSTRACT FROM AUTHOR]

On the Fueguian Atlantic coast and in the southern Andean fold and thrust belt, the Paleogene is partially represented by numerous turbiditic deposits. Between Río Bueno and Cabo Leticia in Península Mitre, the Paleocene-Eocene is represented by the Río Claro Group (Cabo Leticia, La Barca, Punta Noguera, and Cerro Ruperto formations) and the Río Bueno Formation; which together constitute a ~1050-m-thick succession. Calcareous nannofossil assemblages recovered from 95 samples were analyzed to determine their relative ages. The Cabo Leticia Formation was barren in nannofossils. The upper LB2 Member of La Barca Formation contained Rhomboaster cuspis and Fasciculithus richardii, frequent in the Paleocene/Eocene boundary (subzones NP9a/NP9b). Nannofossils recovered from Punta Noguera Formation indicate an early Eocene age (biozones NP9b-NP10), with Fasciculithus tympaniformis, Rhomboaster cuspis, and abundant Toweius spp. The Cerro Ruperto Formation provided one productive sample, with specimens of Reticulofenestra spp. and Toweius spp., which indicates an early Eocene age for the formation (biozones NP12-NP13). The Río Bueno Formation yields calcareous nannofossil assemblages characterized by Chiasmolithus eograndis, Chiasmolithus expansus, Toweius spp., and Reticulofenestra spp., which indicate a late early Eocene to middle Eocene age (biozones NP14-NP15). Although the calcareous nannofossil record is discontinuous due to preservational biases in the Río Claro Group, our data allow a better age constraint for the investigated formations and to correlate these units with other surface and subsurface units in the Austral Basin. [ABSTRACT FROM AUTHOR]

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Paleocene–Eocene phosphorite beds from three major outcrops of the Maknassy-Mezzouna basin (Central-Tunisia) were geochemically investigated to improve local stratigraphy, determine their ages, and attempt to constrain ocean circulation. 87Sr/86Sr ratios of phosphate materials from the Chouabine Formation display a large variation even within the same deposit (87Sr/86Sr between 0.707782 and 0.707830). Based on the Sr isotope data obtained in teeth enamels, further supported by the results in coprolites, Sr isotope ages of 57 ± 1.1 Ma were attributed to Layers I and II, and 62 ± 1.4 Ma to Layer III. These results assign a Paleocene Epoch for the principal phosphate series. The 87Sr/86Sr value of teeth enamel sample from the upper phosphate bed suggests an age of 46 ± 1 Ma for this sequence. Furthermore, the Nd isotopic compositions of these samples were used as a tracer for seawater circulation. The 143Nd/144Nd values of the analyzed samples vary between 0.512174 and 0.512202, corresponding to εNdCHUR between – 8.1 and – 8.4. These values are similar to those reported from Gafsa-Metlaoui basin, southern Tunisia and other North African phosphorite deposits. These data are reminiscent of those of the Atlantic Ocean, which is new argument of the overturning of Tethys Circumglobal Current during the Paleogene period. The obtained results suggest water exchange between Tethys and Atlantic Ocean during this period. [ABSTRACT FROM AUTHOR]

Recognition of the existence of an Andeantype continental margin in southern Tibet prior to its collision with India has provided crucial constraints on the formation of the Tibetan Plateau and South Asian climate evolution. Here, we focused on well-dated Late Cretaceous successions in the Linzhou Basin and determined the elevation changes from sea level to high mountains in the Gangdese magmatic arc in southern Tibet. Our results show that the Linzhou Basin was still submerged in the Tethyan Sea at around 92 Ma when it accumulated Cenomanian (ca. 105-92 Ma) shallow-marine orbitolinid-bearing limestones (Takena Formation); these limestones are unconformably overlain by Campanian (83-78 Ma) fluvial-lacustrine deposits (Shexing Formation) after an ~9 m.y. depositional hiatus. A prominent unconformity between the tightly folded Shexing Formation and gently tilted overlying Paleocene--Eocene Linzizong successions represents the formation of the regional Lhasaplano ca. 70 Ma, which may have been linked to the rise of an Andean-type Gangdese mountain range along the southern margin of the Lhasa terrane. Using carbonate oxygen isotope and clumped isotope thermometry data from the Shexing Formation paleosols, we quantitatively documented the rise of the Andeantype Gangdese Mountains with a peneplain surface at an elevation of 2.7 + 0.5/-0.9 km above sea level prior to onset of the India-Asia collision ca. 65-63 Ma. This scenario of surface gain may have been an isostatic compensation response to the crust thickening to over 50 km during the Late Cretaceous. Subsequently, the surface isostatically rose to its near-present elevation of ~4.6 km due to the removal of overthickened mantle lithosphere and revival of intense Gangdese magmatism by 56 Ma. [ABSTRACT FROM AUTHOR]

After about a century, the skull of the holotype and sole specimen of Arambourgia gaudryi from the Eocene of Quercy (France) is here redescribed. Its interest resides in its extreme morphology, such as its very small skull and altirostral condition, that raises questions about its maturity, taxonomic validity, and paleoecology. In order to reveal previously hidden anatomical details, we used computed microtomography (µCT-scan) data to digitally extract the bones of the cranium and mandible, as well as the endocranial structures. Here, we update the osteological description of A. gaudryi, outlining new characters and re-evaluating anatomical details. Comparing it with ontogenetic series of extant crocodylians, we confirm that the specimen is a mature individual of a dwarf species with pedomorphic features. Our phylogenetic analyses indicate that A. gaudryi is an alligatorine. Comparisons with other small alligatoroid taxa show that it is indeed a valid species. The depositional environment of the finding site suggests a continental context with a karstic network. Taking this into account, together with its peculiar anatomy, we propose that A. gaudryi was a semi-terrestrial animal occupying an ecological niche similar to that of extant juvenile or dwarf crocodylians. Finally, we discuss the current knowledge of the paleobiogeography of Alligatoroidea in Europe during the Paleogene. Arambourgia gaudryi was likely part of a group of small early globidontans that arrived in the Old World, probably from North America, around the end of the Paleocene and that dispersed to at least four localities of the ancient European archipelago. [ABSTRACT FROM AUTHOR]

The Paleocene deposits from the Cerrejón Formation (Colombia, South America) have provided abundant snake remains. All this material has been assigned to the giant snake Titanoboa cerrejonensis. Here, we describe six vertebrae from among the referred materials that do not correspond to Titanoboa. All six vertebrae are morphologically identical, of a similar size, and display a distinct morphology that differs from Titanoboa. This new and unnamed taxon is a large snake estimated to be around eight meters in total length. Anatomical comparisons show that these vertebrae possess certain features typical of the Palaeophiidae, a group of extinct snakes of uncertain relationships known almost exclusively from vertebrae. Among the Palaeophiidae, the new taxon resembles the more generalized forms assigned to the genus Palaeophis, but lacks the extreme aquatic adaptations that define forms assigned to the genus Pterosphenus. We regard the new taxon as an undetermined palaeophiine but do not assign it to Palaeophis as a number of features differ from that described genus. This new record expands the known diversity of aquatic snakes from the Paleogene of South America and provides a substantial new record for the paleogeographic distribution of the Palaeophiidae. The oldest records are from the Cretaceous of Africa, while Paleocene records are poorly known and restricted to Africa, North America, and Europe. The majority of vertebral forms assigned to Palaeophiidae are from the Eocene, principally from the Tethys region, with only one previous South American record coming from the Eocene of Ecuador. [ABSTRACT FROM AUTHOR]

Resolving the Mesozoic and Cenozoic palaeogeography and geomorphologic development of outcropping Variscan basement is a pre-condition for the understanding of central European geodynamics. For our study, we have applied apatite fission-track (AFT) and apatite (U–Th)/He (AHe) thermochronology to surface rocks of the southeastern Bohemian Massif. 46 samples were examined by the AFT method. Additional AHe dating was applied to 8 of them. The AFT ages range from 251 ± 46 to 60.2 ± 4.8 Ma. AHe ages range from 25 to 525 Ma with rather high intra-sample scatter. On a regional scale, the AFT ages generally decrease from mainly late Variscan in the NE to Late Cretaceous and Paleocene in the SW. This regional age asymmetry relative to the NW–SE trending watershed of the Weinsberg Forest is neither compatible with regional uplift of a single block nor with large-scale lithospheric updoming. The lack of age breaks along late Variscan faults demonstrates that strong vertical offset cannot have occurred in Cretaceous and Cenozoic times. Inverse modeling of thermochronological data indicates regional Early Cretaceous cooling and subsequent reheating during the Late Cretaceous. Rocks of the present-day surface were heated up to a temperature of ca. 80 °C without full reset of the AFT system. This thermal history is compatible with the existence of a large mainland in Early Cretaceous times and a subsequent sedimentary reburial until the Campanian on the order of up to 1 km overburden. Parts of the exhumed weathering basal relief to the N and NE of the Weinsberg Forest are inherited as 'sealed relief' from Middle Cretaceous time. The observed regional asymmetry of AFT data is best explained by the development of a continental escarpment adjacent to the North Penninic Ocean in latest Cretaceous to Paleogene times. A final episode of accelerated cooling after ca. 20 Ma, as indicated by thermochronological modeling, is tentatively ascribed to either collisional coupling of the Alpine-Carpathian nappe pile with its northern foreland or to East-Alpine slab detachment. [ABSTRACT FROM AUTHOR]

Bauhinia s.s. is a large genus in the family Fabaceae, but its evolutionary and biogeographical history is still unclear due to the scarcity of fossil records compared to the highly diverse modern species in pantropic regions. Here, we report the earliest fossil record of Bauhinia s.s., namely Bauhinia tibetensis Y. Gao et T. Su sp. nov., based on leaves from the latest Paleocene of the southern Tibetan region. Combined with palaeoecological niche simulations and ancestral state reconstruction, the new fossils suggested a Paleocene origin of Bauhinia s.s. in the Afrotropical realm that subsequently dispersed to the Neotropical and Indomalayan realms. Bauhinia tibetensis belongs to the Asian clade of Bauhinia s.s. that reached the southern Tibetan region from the Afrotropical realm via the Kohistan-Ladakh Island Arc in the early Paleocene. This clade spread to south-eastern China during the Oligocene and entered northern India during the Neogene or earlier. The discovery of the oldest Bauhinia s.s. from what is now the southern Tibetan Plateau updates our understanding of the biogeographical history of this genus and demonstrates that the Kohistan-Ladakh Island Arc is an ancient corridor for floristic interchange between Africa and India. [ABSTRACT FROM AUTHOR]

The record of articulated marine fish fossils during the latest Cretaceous and earliest Cenozoic is sparse. The oldest-known definitive squirrelfishes and soldierfishes, like the first examples of many extant reef-dwelling clades, are known from early Eocene deposits of Europe. Here, we describe a new genus and species of holocentroid (Teleostei: Beryciformes: Holocentroidea) based on material from three individuals from early Paleocene (Danian) deposits of New Jersey, USA using micro-computed tomography. The specimens comprise a three-dimensionally preserved skull and partial postcranium, plus two isolated neurocrania. The new taxon, †Iridopristis parrisi, possesses a unique combination of characters, including a heterosulcoid otolith morphology and an edentulous premaxillary tooth-gap, while lacking a newly proposed character for the remainder of Cenozoic holocentroids: a lamina on the lateral surface of the anguloarticular, anterior to the jaw joint. Bayesian phylogenetic analysis of morphological, stratigraphical and molecular data under the fossilized birth-death process finds that the new taxon branches from the holocentrid stem, where it is joined by two of the three squirrelfish genera from the early Eocene (Ypresian) of Bolca, Italy. We estimate a Danian divergence between Myripristinae and Holocentrinae, the two reciprocally monophyletic subfamilies of Holocentridae. Our analysis suggests that several holocentroid lineages crossed the Cretaceous–Palaeogene boundary. [ABSTRACT FROM AUTHOR]

Premise of research. Fossil infructescences of the late Paleocene Cyclocarya brownii (Juglandaceae) and winged fruits with newly recognized anatomical structure are described from Almont and Beicegel Creek, North Dakota. These fossils demonstrate that C. brownii has many similarities to extant Cyclocarya paliurus but differs in several morphological and anatomical features. Comparisons of the fossil record of Cyclocarya document the transition of characters in the evolution of the oldest extant genus of Juglandaceae. Methodology. Fossils were digitally imaged with reflected light microscopy (LM). Some specimens were embedded in Ward's Bio-Plastic synthetic resin, sectioned into wafers, mounted on microscope slides, and imaged with reflected LM. Permineralized specimens from the Beicegel Creek site were prepared with the cellulose acetate peel technique, mounted on microscope slides, and imaged with transmitted LM. Extant fruits of C. paliurus were photographed from freshly collected material. Pivotal results. Infructescences of C. brownii differ from those of modern C. paliurus in several ways. The fossils are racemes with crowded fruits borne on elongate pedicels. In contrast, extant C. paliurus has spikes bearing fewer fruits per infructescence (10 vs. 23). Fruit wall anatomy is similar to that of extant and other known fossil species of Cyclocarya but is more complex and has a distinctive idioblast layer not present in extant Cyclocarya. Fossil pollen is triporate in contrast to the tetraporate pollen in extant Cyclocarya. As in extant Cyclocarya , pollen is borne both in staminate catkins and occasionally in stamens attached to fruits. We document a fossil fruit with stamens bearing pollen. This feature, sporadic in extant Cyclocarya , was also present in the Paleogene. Conclusions. Late Paleocene C. brownii differs in comparison with extant C. paliurus and related fossil forms in infructescence architecture, fruit size and symmetry, fruit wall anatomy, and pollen aperture number. Trends in character evolution from the Paleogene to the present day include (1) changes from helically arranged, densely distributed pedicellate fruits to sessile fruits borne singly along a slender axis, (2) transition from pyramidal to round nutlets with (3) equatorial versus basal wing attachment, (4) a change in pollen aperture number from three to four, and (5) simplification of the fruit wall in extant Cyclocarya. [ABSTRACT FROM AUTHOR]

New decapod crustaceans from ?Selandian to Thanetian strata of the Kambühel Formation, Austria, include the paguroid Squamipelta insecta new genus and species, and two new galatheoid species, Protomunida kambuehelensis and Annieporcellana paleocenica. The range of Annieporcellana is extended across the Cretaceous-Paleogene boundary. Selandian and Thanetian decapod occurrences are rare; thus, this report adds to the known decapod diversity in the recovery after the end-Cretaceous events. [ABSTRACT FROM AUTHOR]

A study was carried out in the Punjab Platform Basin located in Pakistan to evaluate the potential for hydrocarbon in the early Eocene and Paleocene sequences using petrophysical and geochemical techniques. The assessment of reservoir properties for the Sakesar Formation was carried out using wireline logs, which included measurements of water saturation, hydrocarbon saturation, and porosity. Moreover, 21 well-cutting samples were collected to assess the source rock potential of the Nammal (early Eocene), Dungan, and Ranikot (Paleocene) Formations. The results showed that the Nammal and Dungan Formation samples had low to moderate TOC content, ranging from 0.21 to 2.04 wt.% and 0.45 to 0.56 wt.%, respectively, while the Ranikot Formation samples had moderate to high TOC content, ranging from 0.48 to 1.63 wt.%. The formations under study were found to have a low potential for generating hydrocarbons, as indicated by their S2 values ranging from 0.21 to 2.04 mg HC/g rock. The primary type of kerogen present in these formations was type III and mixed type II/III kerogen, and several plots confirmed the poor generative potential of these formations. The analysis of the Sakesar Formation revealed that it had higher porosity levels at depths of approximately 4163–4197 ft4, with average porosity ranging between 8 and 14% and 68.28% SH and 31.71 Sw, indicating moderate to poor reservoir potential. These findings suggest that the Sakesar Formation could potentially be a moderate-to-good reservoir. [ABSTRACT FROM AUTHOR]

The Paleocene lavas from Dianzhong Formation (E1d) in Linzhou basin of southern Lhasa terrane are a key target for paleomagnetic investigations into the timing and paleolatitude of the initial India‐Asia collision. Controversy exists, however, on whether these rocks preserve a primary remanent magnetization. Here we reanalyze previously published thermal demagnetization data and report detailed rock magnetic results and petrographic observations of these rocks. We find that the original magnetic carrier, a magmatic multidomain Ti‐poor titanomagnetite, underwent significant grain size reduction and was variably reacted to single‐domain maghemite and nano‐hematite. Such strong alteration may have resulted from successive hydrothermal events: a first event related to the ∼52 Ma dike intrusions into the E1d that accompanied a massive ignimbrite eruption deposited above the E1d producing heating up to 300°C; and a secondary event related to the 42–27 Ma southward overthrusting of the basin, heating the E1d up to 130–145°C. Unblocking/inversion temperature spectra of the authigenic maghemite and nano‐hematite overlap with those of the titanomagnetite, implying that the primary remanence of the E1d lavas has been contaminated or replaced by thermoviscous and chemical remanent magnetizations. Thus the isolated characteristic remanent magnetization from these rocks, whether slightly or completely altered, cannot be considered primary and should not be used for paleolatitudinal determination. Our study confirms that hydrothermal alteration can seriously jeopardize the remanence carried by titanomagnetite and thus should be tested for paleomagnetic investigations of rock units from tectonically active areas. Plain Language Summary: The study of past magnetic directions preserved in rocks (paleomagnetism) enables to constrain the paleolatitudes of the southern Asian margin where the rocks formed and is thus key to understand the timing and latitude of the initial India‐Asia collision. However, paleomagnetic studies of Paleogene rocks of southern Tibet have returned a surprisingly wide spread of paleolatitude data. One possible explanation is unrecognized remagnetization, a process that may relate to subsequent hydrothermal alteration. Such hydrothermal alteration has recently been documented for Paleocene lavas in the Linzhou basin, paleomagnetic signals from which have previously been interpreted either as primary or secondary (re)magnetizations. Here we analyze previously published and newly acquired paleomagnetic, rock magnetic, and petrographic data of these rocks to identify whether hydrothermal alteration caused remagnetization, and how such events may be fingerprinted. We find that the original magnetic carrier is Ti‐poor titanomagnetite. Hydrothermal alteration, however, led to significant changes in these titanomagnetite crystals and mineral transformations to maghemite and hematite, associated with acquisition of secondary magnetizations with the magnetic behaviors similar to the primary magnetization. This can be misleading for the interpretation of the magnetic directions obtained from these rocks and imply that they are not suitable for paleolatitudinal determination. Key Points: Hydrothermal alteration intensively destroyed the original multi‐domain titanomagnetite and recorded magnetization in the Dianzhong lavasTitanomagnetite experienced serious grain size reduction and has variably converted to authigenic single‐domain maghemite and nano‐hematitePrimary remanent magnetization has been replaced or contaminated, these lavas should not be used to determine Lhasa terrane paleolatitude [ABSTRACT FROM AUTHOR]

Premise of research. The Anacardiaceae family is distributed throughout the vegetated continents. The fossil record indicates extensive diversification of the family during the Paleogene and, in particular, during the Eocene. Despite the abundant fossil record of this period, there are only a few reliable anacardiaceous fossils in the Paris Basin. Here, we aim to document newly recognized fossils of Anacardiaceae from the Paris Basin, understand their paleoecology, and discuss their biogeographic history. Methodology. Thirty-three lignite fruits were examined from two sites, one before and one after the Paleocene-Eocene boundary (i.e., Petit Pâtis [Rivecourt] and Le Quesnoy [Houdancourt]). The specimens were photographed, and anatomy was studied using computed tomography and histological sections. Comparative analyses were undertaken using available descriptions of fossil and modern fruits of Anacardiaceae. Pivotal results. A new species, Cyrtocarpa biapertura sp. nov., is described on the basis of a unilocular fruit with two prominent apertures present on the ventral side of the endocarp, protruding into two lacunae surrounding the locule. Taphonomic analysis indicates that this plant grew close to riverbanks. Furthermore, a new record of " Lannea " europaea (Reid and Chandler) Chandler is reported for the Eocene site. Conclusions. The occurrence of Cyrtocarpa in both the Paleocene and the Eocene floras in the Paris Basin suggests similar vegetation during both time intervals. It is likely that both floras grew under similar subtropical climates. Moreover, it appears that the early Eocene shows an enrichment of the paleodiversity of Anacardiaceae and other plant families in the Paris Basin. The presence of Cyrtocarpa documents a rarely reported disjunction between the Paleogene of Europe and the recent tropical flora of South America. [ABSTRACT FROM AUTHOR]

Palaeogene sediments of the Hampshire Basin were a sensitive recorder of fluctuations in climate and eustatic sea level as Earth's climate transitioned from the global early Eocene 'hothouse' to the early Oligocene 'coolhouse', accompanied by the first permanent continent‐scale glaciation of Antarctica at the Eocene/Oligocene boundary. A study of the Palaeogene sediments of the Hampshire Basin is not only interesting from a palaeoclimate perspective, but the marine middle Eocene formations are renowned for containing some of the most abundant and diverse Palaeogene fossil assemblages in the world. In this article, I take you on a tour of the geological evolution of the Hampshire Basin from the end of the Paleocene through to the Pleistocene. I highlight some of the best exposures where sediments can be studied at outcrop and representative fossil assemblages can be collected, along with the economic and archaeological significance of these Palaeogene sediments. [ABSTRACT FROM AUTHOR]

Cimolodontan multituberculates are common in the Late Cretaceous and Paleocene of central Asia; they are rarely known from regions south of the Mongolian plateau. Here, we report a new genus and species of multituberculate, Erythrobaatar ganensis gen. et sp. nov., from the Late Cretaceous of Ganzhou, Jiangxi Province, central China, representing the southernmost record of Cretaceous multituberculates in Eurasia. The new species is based on two well-preserved specimens that include cranial and postcranial materials. With a cranium and dentary length of 83 and 66 mm, respectively; it is one of the largest known Cretaceous multituberculates from Eurasia. The present work focuses on the description of the craniodental morphology of the new species, in comparison with that of other Late Cretaceous and Paleogene cimolodontans in order to establish the new taxon. Erythrobaatar ganensis is most closely related to Yubaatar zhongyuanensis and Yubaatar qianzhouensis in the shape and size of the skull and teeth. Phylogenetic analyses place the new species within Taeniolabidoidea, which consists mostly of Late Cretaceous and Paleogene cimolodontans from Asia and North America. The new material also sheds light on tooth replacement, reduction, homologies, and occlusion of multituberculates with a focus on cimolodontans. [ABSTRACT FROM AUTHOR]

The importance of topography generated by Eocene Eurekan deformation as a sediment source for sandstones deposited on the western Barents Shelf margin is evaluated through a sediment provenance study conducted on wellbore materials retrieved from Spitsbergen and from the Vestbakken Volcanic Province and the Sørvestsnaget Basin in the southwest Barents Sea. A variety of complementary techniques record a provenance change across the Paleocene-Eocene boundary in wellbore BH 10-2008, which samples Paleogene strata of the Central Tertiary Basin in Spitsbergen. Sandstones containing K-feldspar with radiogenic Pb isotopic compositions, chrome spinel in the heavy mineral assemblage, and detrital zircons and rutiles with prominent Palaeoproterozoic and Late Palaeozoic—Early Mesozoic U-Pb age populations are up-section replaced by sandstone containing albitic plagioclase feldspar, metasedimentary schist rock fragments, a heavy mineral assemblage with abundant chloritoid, metamorphic apatite with low REE contents, metapelitic rutile with Silurian U-Pb ages and zircons with predominantly Archaean and Palaeoproterozoic U-Pb age populations. Our results clearly demonstrate the well-known regional change in source area from an exposed Barents Shelf terrain east of the Central Tertiary Basin during the Paleocene to the emerging Eurekan mountains west and north of the Central Tertiary Basin during the Eocene. Eocene sandstones deposited in the marginal basins of the southwestern Barents Shelf, which were sampled in wellbores 7316/5-1 and 7216/11-1S, contain elements of both the Eurekan and the eastern Barents Shelf provenance signatures. The mixing of the two sand types and delivery to the southwest margin of the Barents Shelf is consistent with a fill and spill model for the Central Teritary Basin, with transport of Eurekan-derived sediment east then south hundreds of kilometres across the Shelf. [ABSTRACT FROM AUTHOR]

To assess zonal temperature and biogeographical patterns in the Southern Ocean during the Paleogene, we present new multi‐proxy air‐ and sea‐surface temperature data for the latest Paleocene (∼57–56 Ma) and the Paleocene‐Eocene Thermal Maximum (PETM; ∼56 Ma) from the northern margin of the Australo‐Antarctic Gulf (AAG). The various proxy data sets document the well‐known late Paleocene warming and, superimposed, two transient late Paleocene pre‐cursor warming events, hundreds of kyr prior to the PETM. Remarkably, temperature reconstructions for the AAG and southwest Pacific during the latest Paleocene, PETM and Early Eocene Climatic Optimum (∼53–49 Ma) show similar trends as well as similar absolute temperatures east and west of the closed Tasmanian Gateway. Our data imply that the exceptional warmth as recorded by previous studies for the southwest Pacific extended westward into the AAG. This contrasts with modeling‐derived circulation and temperature patterns. We suggest that simulations of ocean circulation underestimate heat transport in the southwest Pacific due to insufficient resolution, not allowing for mesoscale eddy‐related heat transport. We argue for a systematic approach to tackle model and proxy biases that may occur in marginal marine settings and non‐analog high‐latitude climates to assess the temperature reconstructions. Plain Language Summary: For the Cenozoic (past 66 million years) there is a good correspondence between climate conditions derived from numerical models and those from reconstructions on sediment cores, but in some regions fundamental discrepancies between the two require further understanding. We test the extent and potential origin of a remaining discrepancy: the Paleocene‐Eocene southwest Pacific. In this region proxy‐based sea surface temperature reconstructions are much warmer than modeled. Our new temperature reconstructions from the Australo‐Antarctic Gulf are strikingly similar to those from the southwest Pacific, while the closed Tasmanian Gateway separates these two basins into fundamentally different oceanographic settings. The overall pattern might be attributed to systematic underestimation of high‐latitude warm‐current invasion in low‐resolution climate models. A better understanding of temperature proxies in non‐analog climates is likely also required to validate the exceptional high‐latitude warmth recorded in our data. Key Points: Temperature reconstructions for the late Paleocene and Paleocene‐Eocene Thermal Maximum show identical temperature in the Australo‐Antarctic Gulf and the SW PacificThe zonally identical temperatures contrast with climate model runs and projected ocean currentsThe relatively low spatial resolution of current climate models may underestimate heat transport from meso‐scale eddies to the SW Pacific [ABSTRACT FROM AUTHOR]

Pollen and spores were recovered from the Paleocene Fort Union Formation and Paleocene–Eocene Willwood Formation of the Bighorn Basin (BHB), northwestern Wyoming, USA. In many local stratigraphic sections in the BHB, the base of the Eocene has been identified by the characteristic negative carbon isotope excursion (CIE) that marks the beginning of the Paleocene–Eocene Thermal Maximum (PETM). The palynotaxa from outcrop samples were examined using light microscopy (LM) and scanning electron microscopy (SEM). Seven new species are formally described (Tricolpites vegrandis, Rousea spatium, Striatricolporites astutus, Striatopollis calidarius, Friedrichipollis geminus, Retistephanocolporites modicrassus and Retistephanocolporites pergrandis). The temporal and geographic distributions of many of these palynotaxa suggest that hotter and more seasonally dry climates facilitated their northward range shifts during the PETM from the tropics or subtropics of the USA. For the temperate palynotaxa, the hotter and seasonally dry conditions resulted in local extirpation. A re-evaluation of the palynostratigraphic schemes established for the Paleocene–Eocene boundary confirms that the first appearance of Platycarya platycaryoides denotes the Paleocene–Eocene boundary in the Rocky Mountains region. A new Striatopollis calidarius Subzone, associated with early Wasatchian (Wa) Wa-0 and Wa-R faunas, is also recognized for CIE body localities in the BHB. [ABSTRACT FROM AUTHOR]

We describe nearly complete skeletons of basal Anseriformes from the Latest Paleocene to the early Eocene of North America and Europe. Collectively, these birds appear to be representative of anseriforms near the divergence of Anhimae and Anseres, but their exact positions relative to these clades remains uncertain. A new family, Anachronornithidae nov. fam., is erected on the basis of one of these, Anachronornis anhimops nov. gen., nov. gen. et sp., to which the others cannot be confidently assigned. The new fossils augment a growing collection of early Pan-Anseriformes, which in their diversity do not paint an unambiguous picture of phylogeny or character state evolution on the path to or within crown-Anseriformes. Anachronornis nov. gen. is similar in some aspects of both cranial and postcranial anatomy to other well-represented early Paleogene Anseriformes and members of Anseres, such as Presbyornis Wetmore, 1926. However, it exhibits a more landfowl-like bill, like that of Anhimae and unlike the spatulate bill of Anseres. Additional specimens of similar basal Anseriformes of uncertain affinities from the early Eocene of North America and Europe further complicate interpretation of character state polarity due to the mosaicism of primitive and derived characters they exhibit. [ABSTRACT FROM AUTHOR]

A new fossil occurrence of freshwater sponges (Porifera: Demospongiae) is reported from the Deccan volcanic associated Naskal intertrappean locality, deposited in an interval of <100 kyr across the Cretaceous/Paleogene (K/Pg) boundary. This is the oldest record of siliceous fossil birotule spicules (gemmuloscleres) belonging to asexual resting stages typical of the order Spongillida. The analysis supports the ascription of these fossils to the family Palaeospongillidae. The diagnosis and description of Longibirotula Pronzato and Manconi gen. nov. and its type species Longibirotula antiqua Manconi and Samant sp. nov. from the Naskal intertrappean is based on skeletal and gemmular spicular morphotraits. The findings have provided evidence of the presence of diversified groups of freshwater sponges during the Late Cretaceous on the Indian subcontinent and Gondwanaland. From the biogeographic context, the findings track the evolutionary trends of the oldest continental sponges in the Asian and Australasian/Insular Pacific regions. [ABSTRACT FROM AUTHOR]

Sea turtles (Testudines: Chelonioidea) represent a monophyletic group with a global distribution in the fossil record, although most of our knowledge of their diversity and morphology comes from the Atlantic Ocean and Tethyan Sea (Evers and Benson 2019; Gentry et al. 2019). By contrast, the record of their evolution in the vast Pacific Basin prior to the Neogene is paltry. Late Cretaceous chelonioids are known from northern California (Parham et al. 2003), British Columbia (Nicholls 1992; Nicholls and Meckert 2002), Japan (Hirayama and Chitoku 1996), Australia (Kear et al. 2003; Kear 2006; Kear and Lee 2006), and New Zealand (Wiffen 1981), indicating they occupied at least portions of both the North and South Pacific Oceans at this time. Pacific Paleocene specimens are entirely unknown, and to date the Eocene record has been limited to chelonioids and dermochelyids (Köhler 1995a, b; Grant-Mackie et al. 2011) from New Zealand, and an informal report of a sea turtle from Oregon (Orr and Orr 2009). Here, we describe a new sea turtle fossil from the middle Eocene of California which demonstrates that members of this clade were indeed present in the North Pacific at this time. [ABSTRACT FROM AUTHOR]