Search

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]

A palynological study of the uppermost Cretaceous–lowermost Paleocene sequences of the Deccan volcanic province in the Mandla Lobe of central India was carried out to understand floral diversity, palaeoecology and palaeoclimate during Deccan volcanic activity (67.4–62.5 Ma). The study involved 17 intertrappean sedimentary beds at 13 stratigraphical levels. The analysis shows the presence of a rich and diverse palynoflora represented by 47 genera and 61 species of pteridophytes, gymnosperms, algae and fungi. Among these, we recognised three new genera and 10 new species. At the lower stratigraphical levels (582–602 m above sea level), Late Cretaceous (Maastrichtian) age marker palynomorphs, namely Azolla cretacea, Farabeipollis minutus, Jiangsupollis striatus and J. intertrappea sp. nov., and the dominance of Gabonisporis vigourouxii and Aquilapollenites bengalensis were recorded. At the higher stratigraphical levels (698–858 m above sea level), Early Paleocene (Danian) age marker palynomorphs, such as Haloragacidites amolosus, Longapertites vaneendenburgii, Mulleripollis bolpurensis, Palmaepollenites nadhamunii and P. eocenicus, were recorded. The palynoassemblages and associated clay minerals indicate the deposition of intertrappean beds in a fluctuating climate, ranging from humid and semiarid to arid, and the prevalence of estuarine to freshwater depositional environments at the time of deposition. The palynofloral assemblages suggest the prevalence of a warm, humid tropical climate with high precipitation during the deposition of the intertrappean beds. [ABSTRACT FROM AUTHOR]

High-precision ages of Cenozoic volcanic rocks in northeast China are widely reported recently. However, the systematic analysis of spatio-temporal distribution of Cenozoic volcanism, which is important for reconstructing and constraining regional tectonic evolution, is still limited. Here, we collected published geochronological data from more than 400 Cenozoic volcanic samples in northeast China. Combined with field observations of volcanic rock samples and three valid 40Ar-39Ar geochronological data obtained in this study, we compile geochronological data in northeast China and explore a new spatio-temporal distribution pattern for the Cenozoic volcanism in order to constrain geodynamic models for northeast China. Our results show that the Cenozoic volcanism in northeast China has a horseshoe-shaped distribution, and the volcanism almost existed from Paleocene to Quaternary, which can be roughly divided into six volcanic belts. Our results suggest that the volcanism in this region is centred on around the Songliao Basin, then migrates eastward, and eventually has end up with a series of intense activity around the Songliao Basin. This may be related to the upwelling of the asthenosphere caused by the subduction of the Pacific plate and the opening of the Japan Sea. Our study also reveals that Chuandishan basalt in Dunhua area formed by Early Oligocene volcanic activity, which differs from the Pliocene or Miocene stratigraphic ages assumed before. [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]

Late Cretaceous lateral facies and thickness changes are common in the southern Tethyan margin, especially during the final rifting stages of the Tethys and its early onset of closure. Particularly, northern Tunisia, being located closure to a plate boundary, represents an important area to investigate the tectonic influence on sedimentation. In this paper, detailed sedimentological, biostratigraphical and tectonic studies carried out in north-central Tunisia (Serj-Bargou area) to provide more data and precisions on the lithostratigraphy framework and tectonic control on Late Cretaceous deposits. Investigation of field data, high-resolution biostratigraphy, gravity data analysis and lithostratigraphic correlations of strata deposited during the Late Cretaceous allowed us to precisely determine the timing of unconformities and constrain the history of the subsidence inversion of the basin. Three major unconformities have been identified in the SW of Jebel Bargou and span the period from Coniacian to Maastrichtian. These unconformities are marked by Paleocene marls (containing the G. trinidadensis biozone) that unconformably overlie the Late Coniacian series (containing the D. concavata biozone), indicating an early tectonic compressional event in the Late Cretaceous, that probably started in Turonian. Similar tectonic inversion events have already been identified in other Tunisia areas and in the surrounding regional context within the northern and southern Tethyan margin during the Late Cretaceous. This inversion could be explained by a Santonian compressional event, which might have started earlier, in the context of the convergence between African and European plates. The inversion is reflected stratigraphically across the African margin and the intraplate basins, such as the Serj Bargou basin, by a highly reduced accommodation space and unconformities. This tectonic inversion indicates the effects of the change in the poles of rotation related to the opening of the Atlantic at about 83–85 Ma on the former North African passive margin. [ABSTRACT FROM AUTHOR]

Background: The "woody clade" in Saxifragales (WCS), encompassing four woody families (Altingiaceae, Cercidiphyllaceae, Daphniphyllaceae, and Hamamelidaceae), is a phylogenetically recalcitrant node in the angiosperm tree of life, as the interfamilial relationships of the WCS remain contentious. Based on a comprehensive sampling of WCS genera, this study aims to recover a robust maternal backbone phylogeny of the WCS by analyzing plastid genome (plastome) sequence data using Bayesian inference (BI), maximum likelihood (ML), and maximum parsimony (MP) methods, and to explore the possible causes of the phylogenetic recalcitrance with respect to deep relationships within the WCS, in combination with molecular and fossil evidence. Results: Although the four WCS families were identically resolved as monophyletic, the MP analysis recovered different tree topologies for the relationships among Altingiaceae, Cercidiphyllaceae, and Daphniphyllaceae from the ML and BI phylogenies. The fossil-calibrated plastome phylogeny showed that the WCS underwent a rapid divergence of crown groups in the early Cretaceous (between 104.79 and 100.23 Ma), leading to the origin of the stem lineage ancestors of Altingiaceae, Cercidiphyllaceae, Daphniphyllaceae, and Hamamelidaceae within a very short time span (∼4.56 Ma). Compared with the tree topology recovered in a previous study based on nuclear genome data, cytonuclear discordance regarding the interfamilial relationships of the WCS was detected. Conclusions: Molecular and fossil evidence imply that the early divergence of the WCS might have experienced radiative diversification of crown groups, extensive extinctions at the genus and species levels around the Cretaceous/Paleocene boundary, and ancient hybridization. Such evolutionarily complex events may introduce biases in topological estimations within the WCS due to incomplete lineage sorting, cytonuclear discordance, and long-branch attraction, potentially impacting the accurate reconstruction of deep relationships. [ABSTRACT FROM AUTHOR]

The abundance of shark and actinopterygian fossils in the Cretaceous and Paleogene strata of the Atlantic Coastal Plain is well documented; but much remains unknown about the survivorship patterns of these major components of shallow marine faunas in the western Atlantic through the K/Pg mass extinction. To shed light on this subject, we describe an assemblage of new actinopterygian, chondrichthyan, and reptilian microfossils recently recovered from the Maastrichtian Navesink and Maastrichtian-Danian Hornerstown formations at the Jean and Ric Edelman Fossil Park at Rowan University in Mantua Township, New Jersey. The new microfossils clarify extinction patterns across the K/Pg, create temporal and geographic range extensions for several taxa, and expand the known fauna of this regionally-rare and important K/Pg-boundary locality. We report 11 new additions to the vertebrate fauna of Edelman Fossil Park, the first Paleocene record of Saurocephalus lanciformis, the first Cretaceous records ofParalbula marylandica and Palaeogaleus vincenti, and the first recovery of gar and dercetid fish remains from the Paleocene in New Jersey (the last indicating that these fish survived the K/Pg extinction in the western Atlantic). Geographic range extensions include: Notidanodon brotzeni into the Western Hemisphere, Saurocephalus into northeastern North America and Phyllodus paulkatoi to the eastern coast of North America. A dentary of a juvenile alligatorid, Bottosaurus harlani, indicate that the mandible exhibited isometric growth through ontogeny. Our findings generally agree with other studies that these groups were significantly impacted by the extinction event, that extinctions were selective, and recovery was slow. This wealth of novel insights garnered from microfossils in this study highlights their critical importance for elaborating past faunas and illuminating the character of ancient ecosystems. We therefore recommend microsieving as a fruitful method for future faunal studies of shallow-marine strata and predict that such efforts will frequently yield similar important insights. [ABSTRACT FROM AUTHOR]

Research on the provenance of sedimentary systems is key to better understanding the sedimentary framework and improving exploration-associated decision-making and deployment. With regard to the provenance of sedimentary systems, there is still poor understanding in the initial rifting stage due to imbalanced and insufficient exploration and a common lack of seismic data, which have seriously hindered oil exploration in the Qintong Sag, Subei Basin. This study aimed at investigating the provenance in the direction of the fault-terrace zone in the southeast part of the Qintong Sag and aimed to examine whether large-scale sedimentary systems are formed by these sediment sources. Integrated analysis of heavy minerals, sandstone petrologic maturity, drilling cutting dates, 3D seismic data, and well logs was employed to identify the provenance. This study is the first time that large-scale provenance from the direction of the fault-terrace zone has been discovered in the third member of the Paleocene Funing Formation (referred to as the third Mbr of the Funing Fm in this paper) in the Subei Basin, east China. The documentation shows that sediments from the northwest Wubao Low Uplift and the southeast Taizhou Uplift can be distinguished in the Qintong Sag, with the large-scale delta system in the central and eastern part of the Qintong Sag comprising sediments from the Taizhou Uplift, improving upon previous understanding of the sedimentary framework. The deposition formed by the Taizhou Uplift provenance system was characterized by gradual weakening of the hydrodynamic forces, a decreasing sediment supply, and shrinking of the retrogradational delta depositional systems with good reservoir qualities, which are characterized by high-quality source–reservoir–cap combinations and are likely to develop into a hydrocarbon-rich belt. The discovery of the Taizhou Uplift provenance proves that there may be major provenance and large-scale sedimentary systems from the fault-terrace zone of the rift basins in the initial rifting stage. The experience of rapid retrogradation showed that these large-scale delta systems are likely to only flourish in the initial rifting stage. This study is helpful for improving the understanding of sediment provenance and the sedimentary framework of lacustrine rift basins in the initial rifting stage. [ABSTRACT FROM AUTHOR]

Jiaojiang sag in the East China Sea Basin is at the earlier exploration stage, where characterizing hydrocarbon generation of source rocks is important to understand oil-gas exploration potential. Utilizing geochemical and basin modeling analysis, hydrocarbon generation capacity and process of the Paleocene E1y, E1l and E1m formations were investigated. Results show that E1y and E1l mudstones are high-quality source rocks with Type II kerogen, which is dominated by both aquatic organisms and terrestrial higher plants deposited in sub-reduced environment. E1m mudstone interbedded with thin carbonaceous mudstone and coal is poor-quality source rock with Type III kerogen, whose organic matter was originated from terrestrial higher plants under oxidized environment. Controlled by burial and maturity histories, E1y and E1l source rocks experienced two hydrocarbon generation stages, which took place in the Late Paleocene and in the Middle to Late Eocene, respectively, and had high hydrocarbon generation capacity with cumulative hydrocarbon volume of 363 and 328 mg/g, respectively. E1m source rock only had one hydrocarbon generation process in the Late Eocene, which had low hydrocarbon generation capacity with cumulative hydrocarbon volume of only 24 mg/g. The future oil-gas exploration in the Jiaojiang sag should focus on hydrocarbon generation center and select targets in the central uplift formed before the Miocene with high-quality traps. [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]

We report a new ecological refugium for the Cheirolepidiaceae family (pollen form genus Classopollis) in the Paleocene Lower Wilcox Group in the Gulf Coast of southeastern Texas based on palynological analysis of four wells. The Cheirolepidiaceae were once thought to have gone extinct at the Cretaceous-Paleogene (K/Pg) boundary or earlier in North America; however, similar ecological refugia for this family in the Paleocene have previously been reported in China, Argentina, and potentially the Rocky Mountains of the United States. The highest relative abundances of Classopollis pollen were found in delta front, lagoon, and shoreface depositional paleoenvironments marked by high mud-fraction Sr/Ba (a geochemical proxy for salinity), and abundances generally increased down section in older Paleocene strata. The high relative abundance of Classopollis pollen in the well samples, the rarity of reworked Mesozoic palynomorphs, the generally good preservation of Classopollis pollen, and the similarity of Classopollis fluorescence spectra to other in situ Paleocene pollen all provide strong evidence for the survival of the Cheirolepidiaceae family in the coastal salt marshes of Texas through at least the late Paleocene. [ABSTRACT FROM AUTHOR]

The tectonic evolution of the Lishui Sag in the East China Sea Shelf Basin significantly influences its sequence stratigraphy. By integrating seismic reflections, well logs and core data, this study examines the quantitative activity of the Lingfeng fault, sequence framework and sequence architecture in the Lishui Sag. The Paleocene succession is divided into one second-order sequence (SSQ1), three third-order sequences (SQ1–SQ3) and nine system tracts, representing a complete syn-rift evolution consisting of initial syn-rift, rift climax and late syn-rift stages. The results indicate that the differential activity of the Lingfeng fault shapes the basin structure and controls the subsidence centre, leading to prominent variations in the spatial distribution and filling of the sequence stratigraphy during different tectonic stages. The initial syn-rift sequence (SQ1), characterised by a low activity of the segmented Lingfeng fault, is primarily found in isolated small sub-sags. The rift climax sequence (SQ2), with increasing displacement and longer segmented fault zones, exhibits a wedge-shaped filling pattern with substantial topographic elevation differences. The late syn-rift sequence (SQ3) shows a gradual decrease in tectonic activity and uniform filling, with all system tracts within the sequences fully developed. The sequence architecture of the hanging wall in the Lishui Sag can be classified into fault-scarp and fault-slope type, whereas the sequence architecture of the hanging wall dip-slope can be classified into sedimentary slope-break and faulted slope-break. The Lingfeng fault controlled the tectonic evolution, sedimentary subsidence centre and sequence filling and architecture in the Paleocene rifted Lishui Sag. The Paleocene succession is divided into one second-order sequence (SSQ1), three third-order sequences (SQ1–SQ3) and nine system tracts, representing a complete syn-rift evolution consisting of initial syn-rift, rift climax and late syn-rift stages. The sequence architecture of the hangingwall can be classified into fault-scarp and fault-slope type, and hanging wall dip-slope sequence architecture can be divided into sedimentary slope-break and faulted slope-break types. [ABSTRACT FROM AUTHOR]

Palms are known to be an important and diverse angiosperm component in the Deccan Intertrappean beds of Central India. However, the report of fossilized palm stems inhibiting saprophytic fungal remains is empty in the field of paleobotany. Here, we document for the first time the occurrence of fungal remains in a petrified palm stem collected from the latest Maastrichtian (Late Cretaceous)-earliest Danian (early Paleocene) sediments of the Deccan Intertrappean beds of Madhya Pradesh, Central India. The anatomical features of the fossil stem are characterized by the presence of Corypha-type general stem pattern (progressive decrease of fibrous parts of fibrovascular bundles, fvbs from the periphery towards the center), vaginata-shaped fvbs with dorsal fibrous sclerenchymatous part (dcap) adjacent to the phloem, metaxylem vessel element varying from 1 in the outer part to 2 and more (>4) in the inner central zone, and abundant fibrous bundles in the central zone. Based on these anatomical characteristics, our Deccan specimen is confidently placed under extant Corypha-type coryphoid palm taxa belonging to the family Arecaceae and is recognized as a new species Palmoxylon coryphaoides Ali, Roy et Khan sp. nov. The detailed anatomical study of the fossil stem specimen also reveals that it is endogenously infected with well-preserved fungal conidia similar to the modern saprophytic fungus Epicoccum Link. ex Schlecht that are profusely distributed in the metaxylem vessels. The evidence of the current palm species and earlier-reported fossil palm species similar to Coryphoideae collectively indicate the existence of a tropical, warm, and humid environment in the Deccan Intertrappean Beds of Madhya Pradesh during the time of deposition. [ABSTRACT FROM AUTHOR]

A new species belonging to the genus Paratrochamminoidesis here described from the Paleocene at IODP Site U1511 in the Tasman Sea. The species Paratrochamminoides waskowskae n.sp. is characterized by its streptospiral coiling and elongated pseudochambers. A key to the identification of the Paratrochamminoidesspecies is provided. Species are identified on the basis of their chamber shape and predominant mode of coiling. [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]

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]

The mineralogical and chemical characteristics of Upper Cretaceous-Lower Paleocene claystone sediment samples taken from Mardin and Batman, located in southeastern Türkiye, were analyzed in the present study. The clay mineral paragenesis in the Upper Cretaceous units consisted of chlorite-smectite (C-S) and illite, whereas the Lower Paleocene unit consisted of chlorite-vermiculite (C-V) and vermiculite minerals. Analyses conducted on clay samples indicated high levels of Al, Mg, Fe, Cr, V, Ni, and Zr. Low levels of alkali and alkaline earth elements (Mg, Na, Ca, K) in the clay-rich sediments suggest relatively high-grade weathering in the source area. The mineralogical compositions, major elemental ratios, and trace and rare earth element (REE) contents of the sediments indicate that the Upper Cretaceous unit consists of materials with predominantly felsic lithology, whereas relatively detrital contributions from basic sources are found in the Lower Paleocene unit. A comparison of the major and trace element contents of phyllosilicate/clay minerals with the members revealed that the patterns of the clays were distinct from each other. However, the enrichments/depletions varied depending on the origin (basement rocks or detrital) of the derived rocks, minerals, and elements. The major and trace element geochemistry of Upper Cretaceous-Lower Paleocene rocks was associated with a passive margin setting. Sedimentation processes and differences in provenance among members of the Germav Formation during the Cretaceous-Tertiary periods were largely influenced by local or regional geodynamic and diagenetic events. [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]

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]

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]

The Imo Formation (Paleocene), about 500 m thick cropping out around Umuahia and Okigwe areas, is predominantly clayey shale, mudstone, shale, limestone and sandstone. The formation is exposed at Ozuabam in the Afikpo Basin, southeastern Nigeria. Field investigations, petrology, diagenesis and geochemical analyses were undertaken to evaluate the microfacies characteristics of the carbonates, their depositional dynamics and environmental milieus. They are composed of a 22-m thick alternation of black glauconitic shale and carbonates. Bedded, coarse bioclastic facies overly poorly bedded finer lithology of the unit. Calcimetric analysis permits the differentiation of the carbonates into limestone (>90%CaCO3), marly limestone (65-90% CaCO3) and marl (35-65% CaCO3). The limestone is bioclastic grainstone - packstone, composed of fragmented shells of pauperized and low faunal diversity. The underlying silty and marly mosaic facies, with impoverished organic communities, are essentially wackstone-mudstone. Geochemically and mineralogically, the finer carbonates are more siliceous and dolomitic, respectively. Dolomitization was contemporaneous and related to stylolitization and Mg2+ absorption from illite in the illitic and glauconitic shale interbedding units suggestive of a restricted depositional environment for the carbonates. Early diagenetic imprints included glauconitizaton, fragmentation and micritization while pseudo sparitization, pore cementation and dolomitization represent late diagenesis. The fragmented shells indicate energetic depositional process and correspond to facies 2 and 7 of the carbonate microfacies typifying skeletal sand shoal of lagoon fore slope while the marly facies constitute microfacies 9 and 11 and support deposition within a lagoon shelf. [ABSTRACT FROM AUTHOR]

The Caoziwa Pb–Zn deposit is one of the typical vein-type Pb–Zn deposits in the western part of the Tengchong block. Due to limited research, the genesis of these deposits is unknown. In this study, the sulfur isotopic and trace elemental compositions of sulfides from the Caoziwa Pb–Zn deposit were analyzed to trace the sources of ore-forming materials, and to reveal the genetic type of this deposit. The results show that abundant Co, Ni, As, and Se, and less Cu, Zn, Ag, Cd, Sn, Sb, Te, Pb, and Bi could enter pyrite by isomorphic substitution. Elemental Mn, Fe, Cd, Co, and Ni could substitute Zn to enter sphalerite, while the contents of Ag, Sn, and Sb are mainly controlled by the Pb-rich inclusions in sphalerite. Elemental Bi, Sb, Cd, Sn, Ag, and Tl mainly enter the galena grains via an isomorphic substitution mechanism of (Bi, Sb)3+ + (Cd, Sn)2+ + (Ag, Tl)+ ↔ 2Pb2+. Both sulfur isotopic compositions and trace elemental compositions indicate that the ore-forming materials and fluids of the Caoziwa Pb–Zn deposit mainly originate from magmatic hydrothermal fluid related to Paleocene granitic magmatism. Combined with the geological facts that some skarnizations developed in the northern part of the ore field near the Paleocene granite, the Caoziwa Pb–Zn deposit is suggested to be a magmatic hydrothermal vein-type deposit that probably belongs to a distal part of a skarn mineralization system developed by the intrusion of Paleocene granitic magmatism in the western part of the Tengchong block. [ABSTRACT FROM AUTHOR]

Exploration in the Lishui West Sag of the East China Sea Basin is limited by the scarcity of offshore drilling sites, and the prediction of deep, high-quality reservoirs is challenging using only geophysical methods. This study introduces a quantitative approach to diagenetic facies division in individual wells based on logging data, providing a new method and perspective for the prediction of deep, high-quality reservoirs. We employed comprehensive data from core, logging, thin-section casting, cathodoluminescence, scanning electron microscopy, and X-ray diffraction analyses from five wells to study the petrology, physical properties, diagenetic types and strength, and diagenetic minerals of the Paleocene sandstone reservoirs in the Lishui West Sag. Apparent compaction rate, apparent cementation rate, and other quantitative characterization parameters were used to calculate the comprehensive diagenetic coefficient (Cg), and the diagenetic facies were divided into compaction, cementation, and dissolution facies. A logging calculation model for the comprehensive diagenetic coefficient (Cg) and a quantitative identification method for diagenetic facies in individual well reservoirs were established through a fitting analysis between Cg and logging curve parameters. Continuous quantitative identification of vertical diagenetic facies in the five wells in the study area showed that the high-quality reservoirs in wells L1, L2, and L3 within the L1 gas field are characterized by extensive development of dissolution facies, while wells L4 and L5 are dominated by compaction and cementation facies, with poor reservoir properties and no industrial gas flow output. The results demonstrate the reliability of the model method. The establishment of this quantitative characterization method for diagenetic facies using logging data provides guidance for the prediction of favorable reservoirs. [ABSTRACT FROM AUTHOR]

The Nummulites amakusensis Yabe and Hanzawa-- N. junbarensis Matsumaru -- N. hongoensis Hanzawa -- Discocyclina pratti (Michelin) Assemblage (generic term: Amakusa Assemblage) zone of lower Eocene (Ypresian)/middle Eocene (Lutetian), assigned to Letter Stage a2 and the P9 planktonic foraminifera zone in the Philippine Archipelago, is recognized in 20 stratigraphically positioned samples from the Akashimisaki Formation in the Amakusa Islands, Kyushu district Japan, and also in three samples from the Tachien and Meichi Sandstones, Hsuehshan Range, central Taiwan, based on age diagnostic larger foraminifera of five genera and 15 species, together with associated planktonic foraminifera. At the Bozubana locality (station No. 3), Amakusa Islands, unusual white clastic limestone layers in fault blocks of theAkashimisaki Formation yield reworked late Paleocene (Thanetian) larger foraminifera and Late Cretaceous (Maastrichtian) planktonic foraminifera in the Bozubana Thrust Fault zone, which was activated by the Peri Tunghai TectonicMovement in the Ryukyu Arc after the Eocene formations were deposited. The Amakusa Assemblage is proposed for a key regional framework in the eastern Tethys indicating the late Early Eocene (Ypresian)/early Middle Eocene (Lutetian) based on zone P9 and Letter Stage a2. [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]

The lower Paleocene (Danian) Brightseat Formation consists of fine-grained, dark-gray, micaceous sand and silty clay, with glauconite and abundant, but generally poorly preserved, fossils. The Brightseat Formation represents deposition of lower, but not lowermost, Paleocene sediments that were deposited on the middle to outer shelf of what is now the Atlantic Coastal Plain. A basal disconformity separates the Brightseat from the underlying Upper Cretaceous Severn Formation, and it is disconformably overlain by the middle to upper Paleocene Aquia Formation. The type locality of the Brightseat Formation, previously exposed approximately 1 mile (1.6 km) west-southwest of the former village of Brightseat in Prince George’s County, Maryland, just outside of Washington, D.C., has been destroyed by urban development, prompting the establishment of a composite-stratotype section from nearby outcrops approximately a half mile to the south-southwest of the original location. The outcrop at Cabin Branch is hereby designated as the principal reference section for the Brightseat Formation and the “Cabin Creek” outcrop (an informally designated tributary of Cabin Branch) is designated as a supplementary reference section that illustrates the boundary of the Brightseat with the overlying Aquia Formation. Paleontological analyses, grain-size analyses, and petrographic techniques are used to document this new stratotype section and to correlate and contrast it with underlying and overlying sediments. This composite-stratotype section is designated using the guidelines outlined in Article 8, remarks (d) and (e) of the North American Code of Stratigraphic Nomenclature. [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]

More than 20 pinnacle reefs have been discovered in the SE of the Ajdabiya Trough within Paleocene carbonate sediments, most of which are oil-bearing. However, detailed reservoir characterization and conditions governing oil fill-up in this reef have remained unresolved. The major faults provide paths for significant vertical movement of fluids at the edges of the Intisar reef reservoirs. At the same time, the ongoing karst solution collapse also creates vertical zones for fluid encroachment both outside of and within the productive area of the Intisar reef reservoirs. The seismic data show numerous karst-collapse features up to 300 m in diameter that developed shortly after the final drowning of the Intisar 'B' and 'C' reefs. These karst-collapse features may be the main contributing factor in the escape of hydrocarbons within these reefs, which could explain the high water cuts in the Intisar 'B' and 'C' reefs. However, the porosity of the southeastern part of the Intisar 'A' reef has been significantly improved by fracturing and dissolution, as faults associated with fractures are very common in this part of this reef. [ABSTRACT FROM AUTHOR]

In this study Jurassic–Paleogene strata were investigated to understand the litho- and biostratigraphic framework and hydrocarbon source-rock potential of various stratal packages. Biostratigraphic controls were used to establish the chronostratigraphic framework of Jurassic–Paleogene strata in the area. The Lower Jurassic (Hettangian) clastics saw an unconformity during the Sinemurian–Pliensbachian, while the Lower Jurassic (Toarcian)–Middle Jurassic (Bajocian) clastic–carbonate mixed strata is also separated by a Bathonian unconformity from the Middle Jurassic (Callovian) to the Upper Jurassic (Tithonian) carbonate sequence. The Upper Jurassic Oxfordian strata are missing, while the Upper Jurassic (Kimmeridgian)–Lower Cretaceous (Valanginian) glauconitic sandstone and clays are the conformable sequences. The Lower Cretaceous (Hauterivian)–Upper Cretaceous (Turonian) clastics is a conformable sequence that is separated by a Coniacian–Santonian unconformity from the Upper Cretaceous (Campanian) pelagic carbonates. The Cretaceous–Tertiary boundary is marked by laterites, while the Paleocene (Thanetian) sequence is represented by a shale- and sandstone-dominated sequence. The Paleocene (Thanetian)–Early Eocene (Ilerdian) siliciclastic–carbonate mixed sequence marks the last episode of Tethyan sedimentation. Total organic content (TOC), organic petrography and Rock-Eval pyrolysis (REP) techniques were used to evaluate the hydrocarbon source-rock potential, kerogen type and level of maturity of the hydrocarbons. The majority of studied samples show the occurrence of type IV kerogen. However, the Middle Jurassic (Callovian)–Upper Jurassic (Tithonian) carbonate sequence of the Samana Suk Formation, the Kimmeridgian–Valanginian Chichali Formation, the Paleocene (Thanetian) sequence of the Hangu Formation and the Paleocene (Thanetian)–Early Eocene (Ilerdian) Patala Formation confirms the Type III kerogen, poor–fair source-rock quality, immature–mature, gas- and oil-prone indigenous hydrocarbon occurrence in the region. [ABSTRACT FROM AUTHOR]

The results of the study of the meristic and morphometric characters of complete and fragmentary skeletons of Notogoneus gracilis (Gonorynchidae) and Boltyshia brevicauda (Umbridae) recovered from Paleocene–Eocene lacustrine deposits of the Boltysh impact structure are presented in the paper. Some of the specimens previously assigned to Thaumaturus avitus were re-identified as Boltyshia brevicauda. The meristic characters of the specimens considered are stable in both species and refer to those in the respective type series. A previously unknown caudal fin formula (I 6–6 I) is observed in several specimens of Boltyshia brevicauda. The latter species is characterised by more variable meristic characters compared to Notogoneus gracilis. [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]

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]

In order to better constrain the Mesozoic-Cenozoic evolution of the Precambrian Hoggar shield, a paleomagnetic study, combined with detailed fieldwork, was carried out to date its detrital local cover, the Serouenout Formation. Thermal demagnetization yields, only in a few samples, the characteristic remanent magnetization carried by hematite. Post-tilting remagnetization was obtained in sites located along a fault affected by intense fluids circulation. The paleomagnetic directions recorded at seven widespread other sites are on the contrary associated with a positive fold test. It provides a relatively well-defined paleomagnetic pole (A95 = 4.1°), sufficient to estimate the age of the Serouenout Formation. The comparison of this pole with the reference curve of Africa suggests two possible age windows, Triassic and Upper Cretaceous-Lower Paleocene, while the discovery in the uppermost levels of the Serouenout Formation of a fern-rich level with Weichselia reticulata (Bathonian to Cenomanian; Blanco-Moreno et al., 2018) imposes a deposition during the Cenomanian. The presence of a detrital formation at least 350 m thick, with a basal conglomerate containing large pebbles, implies the existence, during this time period, of a tectonic event that generated differential uplift. In addition, structural observations indicate that the Serouenout Formation recorded later brittle tectonics, dominated by a network of vertical N–S dextral faults. The horizontal displacement generated by one well-developed fault has been estimated to be at least 1 km. This activity is related to the known Alpine reactivations of the N–S Pan-African mega-structures, which are still at the origin of the current intraplate seismicity. [ABSTRACT FROM AUTHOR]

Geocellular modeling has become extremely important, linking all petroleum disciplines, and being widely used in simulation and production forecasting in complex basin studies. In this study, we focused on the Minwal–Joyamair Fields in the Upper Indus Basin (UIB), Pakistan, which contains Cambrian to Eocene reservoir formations. Changes in sedimentary environments and structural activities within the UIB have resulted in reservoir heterogeneity, which has adversely affected reservoir performance, and it is still not fully understood. Geocellular modeling was used in this study to better understand the structural framework of the Cambrian to Eocene formations in the UIB. The 2D seismic and well log data from the Minwal–Joyamair Fields are the primary data for building the geocellular model for the Eocene (Chorgali, Sakesar) and Paleocene (Lockhart) reservoirs. The developed structural model is then populated with petrophysical properties such as porosity. The upscaled porosity for the Eocene carbonate rock units ranges 1–3%. On the other hand, the Cambrian and Permian (Tobra & Khewra) clastic reservoirs bear porosity of 3–10%. The upscaled porosity can be utilized to predict the lateral and vertical distribution in these reservoirs. Furthermore, the evaluated upscaled correlation for Eocene reservoirs (80–90%), whereas for Permian (Tobra) and Cambrian (Khewra) reservoirs, it lies between 60 and 70 %. Apart from data availability, a complete geocellular model of the field was produced, encompassing the petrophysical and facies model. The geocellular models created a high-resolution 3D reservoir model of this complex geology that can be applied to similar geology worldwide to identify prospective zones. [ABSTRACT FROM AUTHOR]

Investigating the paleoenvironment and characteristics of source rocks in sedimentary basins is crucial for understanding organic matter accumulation and guiding hydrocarbon exploration. The Lishui Sag, a significant hydrocarbon-bearing depression in the East China Sea, has experienced extensive marine transgression and increasing salinity in the Paleocene, but the changes in accumulation factors of organic matter during this evolution process remain unclear. Through a comprehensive analysis of total organic carbon (TOC), major and trace elements, and biomarker data, this study investigates the characteristics of source rocks from two lithostratigraphic units, namely the Paleocene Yueguifeng and Lingfeng formations, to gain deep insight into the effects of paleoenvironment on organic matter accumulation and hydrocarbon distribution. Our results indicate that the Lishui Sag transitioned from a closed lake to an open-marine environment in the Paleocene, with a shift from warm-humid to arid climate conditions. The biomarker distribution suggests a change in the origin of organic matter, with a higher input of terrestrial organic matter in the Lingfeng Formation. During the early stage, the lacustrine source rocks in the lower Yueguifeng Formation were formed in a relatively humid and anoxic environment within brackish water, resulting in a substantial influx of terrestrial and lacustrine algae organic matter. In contrast, in the late stage, the marine source rocks in the overlying Lingfeng Formation were developed in an arid and oxidizing environment. The lacustrine source rocks in the Yueguifeng Formation were notably more favorable to developing good-quality source rocks. Compared with the other regions, the western and northeastern parts of the study area have greater hydrocarbon generation potential due to the wider distribution of high maturity and organic-rich source rocks, with higher terrestrial and algal organic matter input. Moreover, considering the practical circumstances in the exploration, the northeastern part of the Lishui Sag is recommended as the next exploration target zone. [ABSTRACT FROM AUTHOR]

Large calcite‐cemented sandstone concretions found in Middle Jurassic sandstones from the isles of Eigg and Skye are a striking feature of the Jurassic geology of the Inner Hebrides. Recent clumped isotope data unequivocally give concretionary calcite cementation temperatures above 50°C and up to 98°C. The high temperatures contrast with the mild thermal history of the enclosing less permeable Jurassic mudrocks. The clumped isotope data also enable calculation of the oxygen isotopic composition of the precipitating fluids: these included percolating rainwater that had interacted with Paleocene volcanics; then, later hot fluids of deeper, basinal origin, squeezed out of compacting mudrocks at depth as the Paleocene lava pile loaded the crust. There is thus direct connection between 'Jurassic' sedimentary features and the complex Paleocene volcanic history of the region. [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 earliest phases of mammalian recovery following the Cretaceous–Paleogene (K–Pg) mass extinction are incompletely known but crucial to understanding the development of modern terrestrial ecosystems. Here we report new mammalian faunal data from three vertebrate microfossil assemblages in the Hell Creek region of northeastern Montana, the deposition of which we constrain to within the first 28–80 ka of the Paleocene using new stratigraphic observations within a high-resolution chronostratigraphic framework. We quantified the taxonomic diversity among these three assemblages and five other assemblages from both the Hell Creek region and Denver Basin, together spanning the first ca. 300 ka post-K–Pg mass extinction. Our results allowed us to sub-divide the established 'disaster' and 'recovery' phases of recovery into the following sub-phases: (i) early disaster, characterized by the presence of 'dead clades walking,' high relative abundance of bloom taxa, and the appearance of post-mass-extinction immigrants, (ii) late disaster, characterized by a reduction in the number of 'dead clades walking,' continued high relative abundance of bloom taxa, and a more diverse assemblage of immigrants, (iii) early recovery, characterized by decreased relative abundance of bloom taxa, and continued immigration, and (iv) late recovery, characterized by the onset of in situ diversification. We note important differences in the pattern and timing of mammalian faunal succession between the Hell Creek and Denver Basin, suggesting that post-K–Pg mammalian recovery was spatially heterogeneous. Our results provided a new model for post-K–Pg mammalian biotic recovery that can now be tested with other earliest Paleocene assemblages across western North America. [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]

Although liverworts (Marchantiophyta) are postulated to be one of the oldest lineages of land plants, their documented fossil record is sparse. This study describes five new fossil liverwort gametophytes, one of which bears antheridia, from the Paleocene Paskapoo Formation of Alberta, Canada. The thalli are bilaterally symmetrical, with two undissected wings that bear oppositely arranged dorsal lamellae. One specimen is dichotomously branched, and one bears clusters of antheridia along the midrib area of its dorsal surface. These characters are consistent with those of extant Petalophyllum Nees & Gottsche ex Lehm. (Fossombroniales: Petalophyllaceae), and the genus Petalophyllites gen. nov. (Fossombroniales: Petalophyllaceae) is here erected for these fossils. They are the first representatives of Petalophyllaceae and the Fossombroniales from the fossil record. Most of the specimens are in growth position. Their geologic setting and associated fossils indicate that Petalophyllites lived at the margin of a lake or pond in a habitat that may have been intermittently dry, as is also common in extant species of Petalophyllum. The well-preserved thalli and antheridia of these fossils, and their well-documented middle Paleocene age, provide new evidence of liverwort diversification at the dawn of the Cenozoic Era. [ABSTRACT FROM AUTHOR]

The India‐Eurasia collision is a key case study for understanding the influence of plate tectonic processes on Earth's crust, atmosphere, hydrosphere, and biosphere. However, the timing of the final India‐Eurasia continental collision is debated due to significant uncertainty in the age of the collision between the Kohistan‐Ladakh arc (KLA) and Eurasia along the Shyok suture zone. Here we present paleomagnetic results that constrain the Karakoram terrane in northwest India to a paleolatitude of 19.9 ± 8.9°N between 93 and 75 million years ago (Ma). Our results show that the Karakoram terrane was situated on the southern margin of Eurasia in the Late‐Cretaceous. Our results indicate that the KLA and Eurasian continent had a not converged until <61.6 Ma, placing a Paleocene older limit on the age of final closure of the Shyok suture zone. This suggests that the India‐Eurasia collision in northwestern India likely occurred after the closure of the oceanic basin between the KLA and Eurasia. The Paleocene collision event affecting India that has been widely interpreted to represent final India‐Eurasia collision instead records the arc‐continent collision between the KLA and the northern edge of India prior to final India‐Eurasia collision. Final India‐Eurasia collision in northwest India most likely occurred after the closure of the oceanic basin between the KLA and Eurasia. Plain Language Summary: We use the magnetism of rocks to determine the latitude of the southern edge of Eurasia before the India‐Eurasia continental collision. The results show that the southern edge of Eurasia was situated at 19.9 ± 8.9°N between 93 and 75 million years ago. This latitude means that a volcanic island chain called the Kohistan‐Ladakh arc (KLA) was situated significantly south of the Eurasian continent at the start of the India‐Eurasia collision. Our results suggest that the final stage of continental collision between India and Eurasia in northwest India occurred along the Shyok suture zone, a geological boundary where a major ocean basin once existed between the KLA and Eurasia. Key Points: The Karakoram terrane was on the Eurasian margin at 20°N between 93 and 75 MaThe final closure of the Shyok suture zone occurred after 61.6 million years agoThe Kohistan‐Ladakh arc accreted onto India prior to final India‐Eurasia continental collision [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]

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 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]

Foraminiferal isotopes are widely used to study past oceans, with different species recording conditions at different depths. Their δ18O values record both seawater oxygen‐18 and temperature according to species‐specific fractionation factors, while their Δ47 signatures likely depend only on temperature. We describe an open‐source framework to collect/combine data relevant to foraminiferal isotopes, by constraining species‐specific oxygen‐18 fractionation factors (18α) based on culture experiments, stratified plankton tows or core‐top sediments; compiling stratified plankton tow constraints on living depths for planktic species; extracting seawater temperature, δ18O, and chemistry from existing databases for any latitude, longitude, and depth‐range; inferring calcification temperatures based on the above data. We find that although 18α differs between species, its temperature sensitivity remains indistinguishable from inorganic calcite. Based on > 2,600 observations we show that, although most planktic δ18O values are consistent with seawater temperature and δ18O over their expected living depths, a sizable minority (12%–24%) have heavier‐than‐predicted δ18O, best explained by calcification in deeper waters. We use this framework to revisit three recent Δ47 calibration studies of planktic/benthic foraminifera, confirming that planktic Δ47 varies systematically with oxygen‐18‐derived temperature estimates, even for samples whose δ18O disagrees with assumed climatological conditions, and demonstrating excellent agreement between planktic foraminifera and modern, largely inorganic Δ47 calibrations. Benthic foraminifera remain ambiguous: modern benthic Δ47 values appear offset from planktic ones, yet applying equilibrium Δ47 calibration to the Cenozoic benthic foraminifer record of Meckler et al. (2022, https://doi.org/10.1126/science.abk0604) largely reconciles it with δ18O‐derived temperatures, with discrete Δ47/δ18O discrepancies persisting in the Late Paleocene/Eocene/Plio‐Pleistocene. Key Points: We provide an open‐source, data‐driven framework to collect and combine data relevant to foraminifer isotope recordsΔ47 and δ18O thermometers agree well in planktics and indicate that calcification can sometimes occur below usually assumed living depthsPlanktic Δ47 follows I‐CDES calibrations, challenging prior Cenozoic Δ47 interpretations; benthics may differ and require new observations [ABSTRACT FROM AUTHOR]