207 results on '"PALEOCENE Epoch"'
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2. Petrogenesis and Tectonic Implications of the Granite Porphyry in the Sinongduo Ag-Pb-Zn Deposit, Central Tibet: Constraints from Geochronology, Geochemistry, and Sr-Nd Isotopes.
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Zhang, Peng, Li, Zhuang, Zhao, Feng, and Liu, Xinkai
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PALEOCENE Epoch , *ZIRCON analysis , *PORPHYRY , *CONTINENTAL crust , *ORE deposits - Abstract
The Paleocene ore deposits related to the India–Asia continental collision are widely distributed in the Gangdese metallogenic belt. Among these, Sinongduo is the first discovered epithermal Ag-Pb-Zn deposit in the Lhasa terrane. However, there is still controversy over the ore-forming magma in this deposit. This study mainly reports new zircon U-Pb isotopic ages, whole-rock geochemistry, and Sr-Nd isotopic data for the granite porphyry from the Sinongduo deposit, aiming to discuss the petrogenesis and tectonic setting of the granite porphyry and its genetic link between the Ag-Pb-Zn mineralization. The results show that zircon U-Pb analyses yield ages of 62.9 ± 0.5 Ma and 59.0 ± 0.7 Ma for the granite porphyry, indicating that it formed during the Paleocene period. The timing of the granite porphyry intrusion is contemporaneous with the mineralization, suggesting that it is most likely the ore-forming magma in the Sinongduo deposit. The granite porphyry has high SiO2 and K2O, moderate Al2O3, and low Na2O, CaO, and FeOT contents, and it displays significant enrichments in LREEs and LILEs and depletions in HREEs and HFSEs, with negative Eu anomaly. The granite porphyry is a peraluminous series and can be classified as S-type granite. Moreover, the granite porphyry shows relatively high ratios of (87Sr/86Sr)i and low values of εNd(t). The geochemical and isotopic compositions of the granite porphyry from the Sinongduo area are similar to those of the upper continental crust, which suggests that the granite porphyry was most likely derived from the melting of the upper continental crust in the Lhasa terrane during the India–Asia collisional tectonic setting. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Fossil endocarps of Menispermaceae from the late Paleocene of Paris Basin, France.
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Kara, Eliise, Bardin, Jérémie, De Franceschi, Dario, and Del Rio, Cédric
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PALEOCENE Epoch , *FOSSILS , *SCANNING electron microscopes , *PALEOGENE , *COMPUTED tomography , *CLIMBING plants - Abstract
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]
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- 2024
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4. Paleocene and Eocene deep-water benthic foraminifera at IODP Site U1511, Tasman Sea: Part 2.
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Kaminski, Michael A., Korin, Asmaa, Hikmahtiar, Syouma, Alegret, Laia, and Waśkowska, Anna
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FORAMINIFERA , *EOCENE Epoch , *PALEOCENE Epoch , *BENTHIC animals , *DIAGENESIS , *ENDEMIC species - Abstract
Deep-water benthic foraminifera are investigated from Paleocene to Eocene sediments recovered from IODP Hole U1511B in the northeastern Tasman Sea. The recovered foraminifera display exceptional three-dimensional preservation: they are relatively unaltered by sediment diagenesis and compaction.We examined 33 samples from Cores U1511B-33R to -42R, and recovered 79 species of deep-water agglutinated foraminifera (DWAF) and 13 species of calcareous benthic foraminifera. The assemblage consists entirely of "cosmopolitan" forms originally described from the Carpathians, Caucasus, Trinidad, and the western Tethys, and other DSDP/ODP sites, implying that there is little or no endemism among deep-water benthic faunas in the semi-isolated Tasman Sea. The Paleocene--Eocene interval is characterized by successive acmes of Spiroplectammina, Trochammina, ammodiscids, and Karrerulina, and therefore bears striking similarity to previously studied sections in the western Tethys and Boreal North Atlantic. The taxonomic turnover among the DWAF is minor across the P/E contact, with only three apparent extinctions and three originations from the uppermost cores of the Paleocene and the lowermost cores of the Eocene. Calcareous benthic foraminifera were not observed in the Eocene samples, possibly a result of the shoaling of the CCD. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Carbonate U‐Pb Ages Constrain Paleocene Motion Along the Altyn Tagh Fault in Response to the India‐Asia Collision.
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Yi, Kexin, Cheng, Feng, Jolivet, Marc, Li, Jiaming, and Guo, Zhaojie
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STRIKE-slip faults (Geology) , *PALEOCENE Epoch , *PALEOGENE , *URANIUM-lead dating , *CENOZOIC Era , *GEOLOGIC faults , *CARBONATES , *CALCITE - Abstract
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]
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- 2024
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6. Tectono-stratigraphic evolution in the Paleocene Lishui Sag, East China Sea Shelf Basin.
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Zhu, Z., Qi, L., Chen, H., Li, J., Zhang, Y., Qin, J., Zhao, Y., and Ni, C.
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PALEOCENE Epoch , *SEQUENCE stratigraphy , *FAULT zones , *RIFTS (Geology) , *SPATIAL variation , *SEDIMENTARY basins - Abstract
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]
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- 2024
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7. Paratrochamminoides waskowskae n. sp., a new deep-water agglutinated foraminifera from the Paleocene of the Tasman Sea.
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Kaminski, Michael A., Korin, Asmaa, and Hikmahtiar, Syouma
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PALEOCENE Epoch , *FORAMINIFERA , *DEEP-sea animals , *MODE shapes - Abstract
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]
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- 2024
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8. Latest Cretaceous and Paleocene biostratigraphy and paleogeography of northern Zealandia, IODP Site U1509, New Caledonia Trough, southwest Pacific.
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Crouch, Erica M., Clowes, Chris D., Raine, J. Ian, Alegret, Laia, Cramwinckel, Margot J., and Sutherland, Rupert
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PALEOCENE Epoch , *PALEOGEOGRAPHY , *BIOSTRATIGRAPHY , *FOSSIL microorganisms , *PALEOGENE , *POLLEN , *SUBDUCTION - Abstract
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]
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- 2024
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9. A new species of Palaeohypotodus Glückman, 1964 (Chondrichthyes, Lamniformes) from the lower Paleocene (Danian) Porters Creek Formation, Wilcox County, Alabama, USA.
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Ebersole, Jun A., Cicimurri, David J., and Harrell Jr., T. Lynn
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INCISORS , *GEOLOGICAL surveys , *COASTAL plains , *PALEOCENE Epoch , *DENTITION - Abstract
The historic collection of the Geological Survey of Alabama includes several fossil shark specimens that were recovered from the lower Paleocene Porters Creek Formation in southwestern Alabama, USA. Among these specimens are 17 teeth that we herein recognize as a new species within the extinct Paleogene genus, Palaeohypotodus. Detailed examination of these individual teeth, coupled with analyses of the dentitions of various extant lamniform sharks, allowed us to confirm monognathic and dignathic heterodonty within Palaeohypotodus. We identified upper and lower anterior and lateral tooth files that can be differentiated from one another by minor variations in morphology. Additionally, numerous isolated teeth from other Danian exposures in Alabama and Arkansas, USA , enhance our understanding of the composition of the dentition and ontogenetic heterodonty of both the new species and the genus as a whole. [ABSTRACT FROM AUTHOR]
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- 2024
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10. The early Paleocene (Danian) climate of Svalbard based on palaeobotanical data.
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Golovneva, Lina B., Zolina, Аnastasia А., and Spicer, Robert A.
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PALEOCENE Epoch ,FOLIAR diagnosis ,ARCTIC climate ,SNOW cover ,PALEOGENE ,GINKGO ,FERNS ,WINTER ,SUMMER - Abstract
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]
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- 2023
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11. Petalophyllites speirsiae gen. et sp. nov. (Marchantiophyta: Fossombroniales), a fossil liverwort gametophyte from the Paleocene of Alberta, Canada.
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Hoffman, Georgia L. and Crandall-Stotler, Barbara J.
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PALEOCENE Epoch , *LIVERWORTS , *CENOZOIC Era , *FOSSILS , *MIDDLE age - Abstract
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]
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- 2023
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12. Paleocene Glauconite of the Near-Volga Monocline of Submarine Volcanic Sedimentary Genesis.
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Nikulin, Iv. Iv., Boeva, N. M., Soboleva, S. V., and Bortnikov, N. S.
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GLAUCONITE , *PALEOCENE Epoch , *SETTLING basins , *SUBMARINE volcanoes , *ZEOLITES , *PALEOGENE , *MINERALS - Abstract
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]
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- 2023
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13. Paleogene Stratigraphy and Foraminifera of the Submarine Lomonosov Ridge, Arctic Ocean.
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Bugrova, E. M.
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FORAMINIFERA , *MID-ocean ridges , *PALEOGENE , *PALEOCENE Epoch , *OCEAN , *BIOSTRATIGRAPHY - Abstract
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]
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- 2023
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14. Litoestratigrafía y bioestratigrafía como herramientas de exploración de fósiles de vertebrados en Socha (Colombia).
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Velandia Angarita, Omar Rodrigo, Mariño Martínez, Jorge Eliecer, and Giraud López, Marie Joelle
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PROSPECTING , *PALEOCENE Epoch , *SANDSTONE , *SEDIMENTATION & deposition , *CROCODILES , *FOSSILS - Abstract
In the northeastern zone of the department of Boyacá, in the locality of Socha, areas with a high fossiliferous potential of microvertebrates and vertebrates, as fish, crocodiles and, particularly, turtles, of middle and upper Paleocene age of the Arcillolitas de Socha Formation have been identified. Along this sector, detailed stratigraphic sections and geological profiles were elaborated, which together with lithostratigraphic and biostratigraphic techniques, allowed us to differentiate the formation into three members and to identify the prospecting areas of two fossiliferous levels of interest, as well as a group of key sandstones located in the intermediate levels. The paleoenvironments identified for the formation indicate a lagoonal, marshy, paludal, and deltaic sedimentation for the sandstones, generally sedimented in a continental depositional environment. All the information obtained could be applied for the eventual location of fossils in prospecting and exploration in subsequent research, as well as highlighting the imperative need to strengthen local laws in favor of the protection and preservation of these paleontological deposits in the region. [ABSTRACT FROM AUTHOR]
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- 2023
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15. A new definition of the Paleocene Shallow Benthic Zones (SBP) by means of larger foraminiferal biohorizons, and their calibration with calcareous nannofossil biostratigraphy.
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Papazzoni, Cesare Andrea, Fornaciari, Beatrice, Giusberti, Luca, Simonato, Michela, and Fornaciari, Eliana
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BENTHIC zone , *PALEOCENE Epoch , *NANNOFOSSILS , *BIOSTRATIGRAPHY , *WATER depth , *CALIBRATION , *MARL - Abstract
Three key Paleocene deep-sea sections cropping out in northern Italy contain intercalations of calciturbiditic, larger foraminifera-bearing beds derived from shallow water environments. The reconstructed Southern Alps record obtained by splicing the three sections allowed a direct correlation of the shallow benthic SB and calcareous nannofossils CN Zones, leading new data about the Shallow Benthic biozonation for the Danian-Thanetian interval and proposing four new SBP (Shallow Benthic Paleocene) Zones (SBP1-4). Such revision relies on an innovative biostratigraphic approach based on larger foraminiferal biohorizons instead of marker species according to the traditional approach used since the introduction of the SB Zones. Based on our study, the SBP1/SBP2 boundary turns out to be about 2 Ma after the K/Pg crisis, highlighting a quite fast recovery of the complexity among foraminifera. [ABSTRACT FROM AUTHOR]
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- 2023
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16. The oldest fossil record of Bauhinia s.s. (Fabaceae) from the Tibetan Plateau sheds light on its evolutionary and biogeographic implications.
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Gao, Yi, Song, Ai, Deng, Wei-Yu-Dong, Chen, Lin-Lin, Liu, Jia, Li, Wei-Cheng, Srivastava, Gaurav, Spicer, Robert A., Zhou, Zhe-Kun, and Su, Tao
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BAUHINIA , *FOSSILS , *LEGUMES , *ISLAND arcs , *PALEOCENE Epoch , *PALEOGENE - Abstract
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]
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- 2023
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17. Selective extinction at the end-Cretaceous and appearance of the modern Decapoda.
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Schweitzer, Carrie E and Feldmann, Rodney M
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DECAPODA ,MASS extinctions ,PALEOCENE Epoch ,CRABS ,CRUSTACEA ,HABITATS - Abstract
Extinction and origination of genera and families of marine Decapoda at the end of the Cretaceous established the modern fauna. Podotrematous crabs suffered high extinction levels, whereas heterotrematous crabs experienced both extinction and radiation. Anomuran decapods exhibited high extinction levels at the generic but not family level. In general, family extinctions predominantly occurred among podotrematous and heterotrematous crabs, which also exhibit overall shorter family ranges. Possible refugia promoted survival of genera and families into the Paleocene, whereas habitation of the Western Interior Seaway ensured high levels of extinction. Areas proximal to the Chicxulub impact site experienced moderate levels of extinction. Habitat specialists preferentially survived the end-Cretaceous extinction in some clades. Heterotrematous crabs recovered rapidly in the Paleocene, especially in the siliciclastic environments of the Americas. Because decapod crustaceans are highly variable in morphology, habitat, and ecology, no one pattern of extinction and recovery can explain the end-Cretaceous decapod extinction event. Rather, a mosaic of responses in various decapod groups led to their differential survival. [ABSTRACT FROM AUTHOR]
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- 2023
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18. Assessing the potential for hydrocarbon generation in early Eocene and Paleocene sequences of the Punjab Platform Basin, Pakistan, through geochemical and petrophysical analysis.
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Shah, Syed Bilawal Ali
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PALEOCENE Epoch ,ANALYTICAL geochemistry ,HYDROCARBONS ,KEROGEN ,EOCENE Epoch ,PALEOGENE ,VALUATION of real property - Abstract
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]
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- 2023
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19. The oldest birotule-bearing freshwater sponges from the Upper Cretaceous-lower Paleocene Deccan volcanic-associated sediments of India.
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SAMANT, BANDANA, PRONZATO, ROBERTO, MOHABEY, DHANANJAY MAHENDRAKUMAR, CUBEDDU, TIZIANA, STOCCHINO, GIACINTA ANGELA, JANGALE, KRUTIKA, THALAL, PRANAY, DHOBALE, ANUP, and MANCONI, RENATA
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PALEOCENE Epoch , *FRESH water , *PALEOGENE , *SEDIMENTS , *DEMOSPONGIAE , *SPONGES (Invertebrates) ,GONDWANA (Continent) - Abstract
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]
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- 2023
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20. First Report of Burdurina selandinica Sirel (Foraminiferida) and the Microfacies Analysis of Middle Paleocene Limestones in Central Iran.
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Deveciler, A., Hadi, M., Sarkar, S., and Sharifi, J.
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PALEOCENE Epoch , *BENTHIC zone , *LIMESTONE , *FORAMINIFERA , *CORAL reefs & islands - Abstract
Burdurina selandinica Sirel from Paleocene carbonates of the Golbui section of Central Iran is reported and discussed. The stratigraphic position of foregoing succession is consistent with the previous studies depending on the faunal assemblage of the Selandian–early Thanetian, namely Sistanites iranicus Rahaghi, Anatoliella sp., Haymanella paleocenica Sirel, Coscinospira prima Schlagintweit et al., Miscellanea cf. yvettae Leppig, Elaziginadienii (Hottinger), Idalina sinjarica Grimsdale,Pachycolumella acuta Septfontaine et al., Pachycolumella elongata Septfontaine et al., Rotospirella conica (Smouth). After the latest reorganization on Shallow Benthic Zones (SBZs) of the Paleocene, two stages correspond to SBZ3. Three predominant microfacies types including coral-coralline algal framestone, bioclastic foraminiferal-peloidal grainstone-packstone and coral floatstone were recognized in the studied section. The microfacies gradients within the succession and paleoenvironmental analysis suggest deposition in a shallow-marine ramp environment that is located in a global carbonate platform stage I from the middle paleolatitude. [ABSTRACT FROM AUTHOR]
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- 2022
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21. Geochemistry and Mineralogy of Paleocene Coal from the Padhrar and Darra Adam Khel Coalfields of Pakistan.
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UMAIR, Muhammad, YANG, Ruidong, CHENG, Wei, and KHATTAK, Salman Ahmed
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COAL , *GEOCHEMISTRY , *PALEOCENE Epoch , *TRACE elements , *COALFIELDS , *MINERALOGY - Abstract
Pakistan is rich in coal resources, which amount to around 186 billion tons. The Paleocene Padhrar and Darra Adam Khel coalfields are located in the Central Salt Range Punjab Province and the Khyber Pakhtunkhwa Province, Pakistan, respectively. Padhrar coal has not been studied in detail and the Darra Adam Khel coalfields are newly‐discovered, so no research has been done, due to security considerations. In this study, an attempt has been made to study the geochemical and mineralogical characteristics of the Padhrar and Darra Adam Khel coals, in order to learn about the coal quality, element enrichment mechanism, sedimentary medium conditions and potentially valuable elements for coal utilization. The Padhrar and Darra Adam Khel coals are low to medium ash, low moisture content, high in volatiles and high total sulfur coal. The vitrinite reflectance in Darra Adam Khel coal is higher than in Padhrar coal, indicating either a greater burial depth or the effects of Himalayan tectonism. The vitrinite content is dominant in the Padhrar and Darra Adam Khel coals, followed by inertinite and liptinite, the major minerals including quartz, clay minerals, calcite and pyrite. The trace elements Ni, As, Be Zn, Ge, Mo, Ta, W, Co and Nb, Sn, Hf, Ta, Pb, Th, Cd, In, Be, V, Cr, Zr, Ag, Li, W and Co are concentrated in some of the Padhrar and Darra Adam Khel coal samples, respectively. The Padhrar coal shows positive Ce, Eu and Gd anomalies, with most of the Darra Adam Khel coal showing negative Ce, Eu and positive Gd anomalies with high LREE. The Al2O3/TiO2 values indicate that the sediment source of the Padhrar and Darra Adam Khel coals is mostly related to intermediate igneous rocks. The Sr/Ba, SiO2 + Al2O3, Fe2O3 + CaO + MgO/SiO2 + Al2O3 and high sulfur content in the Padhrar and Darra Adam Khel coals indicate epithermal and marine water influence with a tidal flat, coal‐forming environment and a deltaic coal‐forming environment, respectively. [ABSTRACT FROM AUTHOR]
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- 2022
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22. The angiosperm pollen Volkheimerites labyrinthus gen. et sp. nov. from the earliest Paleogene (Danian) of Patagonia, Argentina.
- Author
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Narváez, Paula Liliana, Mego, Natalia, Silva Nieto, Diego Gonzalo, Prámparo, Mercedes Beatriz, and Cabaleri, Nora Graciela
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PALEOGENE , *POLLEN , *ANGIOSPERMS , *PLANT diversity , *PALEOCENE Epoch , *GRAIN - Abstract
Volkheimerites labyrinthus gen. et sp. nov., an angiosperm pollen type, is fully described and illustrated. The specimens were retrieved from lower Paleocene strata of the Salamanca Formation (San Jorge Basin) located in Chubut Province, Patagonia, Argentina. Medium to large size (25.5–55 μm) and a characteristic striate sculpture with labyrinthine pattern are distinguishing features of the grains in this new genus. Volkheimerites labyrinthus shares the presence of a coarse tectum supported by columellae with the fossil genera Dichastopollenites, Trisectoris and Periretisyncolpites, and some Winteraceae and Annonaceae species, but differs in having striate-labyrinthine as opposed to reticulate ornamentation. Our material is also distinguishable by the occurrence of solitary grains (monads) instead of the more frequent presence of tetrads in the Winteraceae family or grains separated into two hemispheres as in Dichastopollenites. The large thin area of the exine appears to be morphologically analogous to the proximal thinning of the exine in the monads of tetrads as occurs in some Annonaceae species. The detailed description and illustration of this new angiosperm pollen genus expands our understanding of Paleocene plant diversity in Patagonia. [ABSTRACT FROM AUTHOR]
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- 2022
- Full Text
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23. A new agglutinated foraminiferal species (Arenoturrispirillina waskowskae sp. nov.) from the Danian of Contessa, Italy.
- Author
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Hikmahtiar, Syouma and Kaminski, Michael A.
- Subjects
FORAMINIFERA ,SPECIES ,PALEOGENE ,PALEOCENE Epoch - Abstract
This paper describes a new Paleogene deep-water agglutinated foraminifera from the Contessa Highway Section, Umbria-Marche Basin, Italy. The new species Arenoturrispirillina waskowskae is characterised by its predominently high trochospiral coiling, which distinguishes it from the genus Glomospira. The new species is also found in the Polish Carpathians. [ABSTRACT FROM AUTHOR]
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- 2022
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24. Geochemical Characteristics and Environmental Implications of Trace Elements of the Paleocene in the West Lishui Sag, East China Sea Basin.
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Yang, Shuai, Fu, Qiang, Liu, Jinshui, Ma, Wenrui, Yang, Bing, Zhu, Zhiwei, and Teng, Wen
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- *
PALEOCENE Epoch , *OXYGEN isotopes , *CARBON isotopes , *SEDIMENTARY structures , *TRACE elements , *DRILL core analysis - Abstract
Analysis of the sedimentary environment during the clastic formation process is of great significance for reservoir evaluation and desert prediction. This paper focused on the Paleocene in the West Lishui Sag, East China Sea Basin. XRF fluorescence diffraction and carbon and oxygen isotope tests were carried out on core samples from four wells. Based on the geochemical characteristics of the samples and the changes in the elemental ratios, combined with the lithologic characteristics and sedimentary structure of the samples, the paleoclimate, paleosalinity, paleobathymetric, paleoredox, paleotemperature, and other paleoenvironmental characteristics were analyzed. The results show that the characteristics of major and trace elements were similar in the lower Mingyuefeng Formation (E1m2), Upper Lingfeng Formation (E1l1), Lower Lingfing Formation (E1l2), and Yueguifeng Formation (E1y). The Paleocene in the West Lishui Sag was mainly in the reducing environment of brackish-salt water with weak water stratification. The water depth showed a trend of becoming deeper, then shallower, and then deeper. The paleoclimate in the West Lishui Sag was warm on the whole. However, the content of Sr became smaller after later deposition, so the calculated paleowater temperature was higher. In addition, oxygen isotopes were affected by diagenesis, resulting in a negative oxygen isotope value. The paleoproductivity was low, and the hydrocarbon generation potential was poor. The content of nutrient elements mainly came from terrigenous input rather than biological origin, and terrigenous intrusion characteristics gradually increased from E1y to E1m2. The study also shows that paleoproductivity was affected by the paleoclimate and paleowater depth. Warm and humid climate and deep water body were conducive to the accumulation of paleoproductivity. [ABSTRACT FROM AUTHOR]
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- 2022
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25. Lithostratigraphy and Biostratigraphy Based on Calcareous Nannofossils at the Late Campanian to Thanetian Transition in the Izeh Zone, Southwestern Iran (Eastern Neo-Tethys).
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Senemari, Saeedeh
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NANNOFOSSILS , *BIOSTRATIGRAPHY , *PALEOCENE Epoch , *PALEOGENE , *MARL , *IRIDIUM , *JEANS (Clothing) - Abstract
This study investigates the Gurpi Formation in the northeast of Izeh, southwestern Iran. In this study, 59 species and 34 genera were determined. Biostratigraphy allows the identification of zones CC21 to CC26, which is equivalent to the UC15cTP-UC20dTP that spans the Late Campanian to Late Maastrichtian. Subsequently, the presence of NP1 to NP6, equivalent to CNP1 to CNP8, indicates that the sequence extends to Selandian. Then the Pabdeh Formation, which dates back to Thanetian, covers the sequence. Several major changes were recorded here in order of importance. The first change is the Campanian-Maastrichtian transition, which was identified based on the last occurrence of the Aspidolithus parcus constrictus. Subsequently, the Early/Late Maastrichtian boundary was determined based on the last occurrence of Reinhardtites levis. In addition, another change in the Late Maastrichtian—Early Danian is associated with an abrupt decrease in the richness of nannofossils, although a significant increase in the abundance of Early Paleocene new species has been observed along with the abundance of Thoracosphaera spp. blooms. Eventually, the final change coincides with an increase in Iridium throughout NP1. These changes may indicate changes in environmental conditions in this part of Iran during the Late Cretaceous—Paleogene transition in the eastern Neo-Tethys domain. [ABSTRACT FROM AUTHOR]
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- 2022
- Full Text
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26. Sulfur Isotopic Composition of Gypsum from Paleocene, Northwest China: Implications for the Evolution of Eastern Paratethys Seawater.
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Wang, Jun and Cao, Yangtong
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SULFUR cycle , *PALEOCENE Epoch , *SEAWATER composition , *SEAWATER , *SULFUR isotopes , *GYPSUM - Abstract
The sulfate isotope record of marine sedimentary sulfate through time has been used successfully to determine global variations in the composition of seawater sulfate. The variations in the sulfur isotope composition of marine sulfate reflect changes in the global sulfur cycle and are also closely related to changes in the atmospheric oxygen cycles. However, data for the Paleocene are very sparse and the stratigraphic evolution of the sulfur isotope composition of seawater is poorly constrained due to the small number of samples analyzed. The Yarkand Basin, as a northeastern part of the eastern Paratethys ocean with the trumpet-shaped bay, in which a suite of evaporitic sequences named the Aertashen Formation was continuously developed in the Paleocene and was principally composed of massive gypsum interbedded fragmental rocks. The values of sulfur isotopic composition are from 12.2‰ to 20.6‰ (δ34 SCDT or δ34 SVCDT) and the mean is 17.7‰ in 97 gypsum samples in the basin. Three gradually increasing trends of sulfur isotopic curves reflect that enrichment of δ34 S occurred in seawater sulfate, and indicate oxidation of seawater sulfide. These may hint to at least three oxidation events or the bacterial reduction of seawater sulfide that occurred in the Paleocene, and that three oxygen-enriched events or the biological sulfur cycle might exist in this epoch. The sulfur isotopic composition (δ34 SCDT or δ34 SVCDT) in the seawater of the northeastern part of the eastern Paratethys ocean was about 15.0‰ to 20.6‰, and averaged 17.9‰ in the Paleocene. Combined with the previous global sulfur isotopic composition of seawater, the final range of global sulfur isotopic composition of seawater might be from 15.0‰ to 21.0‰, with 17.9‰–18.3‰ the average in the Paleocene, so the variations in the sulfur isotope composition of Paleocene seawater sulfate are reconstructed and supplemented. [ABSTRACT FROM AUTHOR]
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- 2022
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27. Paleosalinity Reconstruction for the Paleocene Sequence of Lishui Sag in the East China Sea Shelf Basin.
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Sun, Long, Zhang, Jinliang, Zhang, Tianya, Yan, Xue, Chen, Tao, and Liu, Jinshui
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PALEOCENE Epoch , *BRACKISH waters , *PETROLEUM prospecting , *NATURAL gas prospecting , *FRESH water , *PROVENANCE (Geology) - Abstract
The Lishui Sag on the southwest margin of the East China Sea Shelf Basin (ECSSB) is a relatively new oil and gas exploration area, with the Paleocene being one of the most potential oil-bearing intervals in the sag. In this study, combined with the principles of element geochemistry and mineralogy, the salinity characteristics of the paleowater body are reconstructed and discussed using the Sr/Ba ratio, B/Ga ratio, equivalent boron content and Couch's method. The results show that (1) the highest salinity indicated by Sr/Ba and B/Ga ratios appears in the Upper Lingfeng Formation; (2) the equivalent boron content ranges from 62 to 254 ppm, with an average of 122 ppm, showing the existence of fresh water and brackish deposition settings; and (3) the paleosalinity calculated quantitatively by Couch's method is between 4.9 and 13.1‰. To ensure the reliability of the study, paleosalinity results from the different methods are cross-plotted, and the effects of provenance and diagenesis on the paleosalinity analysis are negligible. The comparison results show that Couch's method, equivalent boron content and B/Ga ratio are more reliable among all paleosalimeters. The identified paleosalinity type of paleowater body is mainly brackish water, which is exactly mesohaline water. The paleosalinity of the Paleocene stratigraphic interval in Lishui Sag is consistent with the sedimentary facies distribution. Our comprehensive comparison provides a basis for inferring the source of fresh water, the genesis of transitional water bodies and the evolution of sedimentary facies. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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28. Petrosal and bony labyrinth morphology of the stem paenungulate mammal (Paenungulatomorpha) Ocepeia daouiensis from the Paleocene of Morocco.
- Author
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Gheerbrant, Emmanuel, Schmitt, Arnaud, and Billet, Guillaume
- Subjects
- *
PALEOCENE Epoch , *SKULL morphology , *MORPHOLOGY , *MIDDLE ear , *ANATOMY , *INNER ear , *SEMICIRCULAR canals - Abstract
Based on high‐resolution computed tomography, we describe in detail the petrosal and inner ear anatomy of one of the few known African stem paenungulates (Paenungulatomorpha), Ocepeia daouiensis from the Selandian of the Ouled Abdoun phosphate basin (Morocco). The petrosal of Ocepeia displays some remarkable, probably derived features (among eutherians) such as relatively small pars cochlearis, pars canalicularis labyrinth (including small semicircular canals), a large wing‐like pars mastoidea, a large and inflated tegmen tympani, and the dorsoventral orientation of the large canal for the ramus superior. The presence of small semicircular canals in Ocepeia is an interesting shared trait with tenrecoidean afrotherians. Otherwise, and consistent with a general primitive skull morphology, the middle ear and labyrinth of Ocepeia daouiensis is characterised by many plesiomorphic traits close to the eutherian generalised plan. This adds to the rather generalised morphology of the earliest crown paenungulates such as Eritherium, Phosphatherium and Seggeurius to support an ancestral paenungulatomorph morphotype poorly derived from the eutherian pattern. As a result, Ocepeia provides key morphological and fossil data to test phylogenetic relationships of the Afrotheria (including Paenungulatomorpha) at the placental root mostly inferred from molecular studies. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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29. Composition of Paleocene forests from Antarctica based on fossil wood.
- Author
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Tilley, Laura Jane
- Subjects
- *
FOSSIL trees , *TEMPERATE forests , *WOOD , *PALEOCENE Epoch , *UPLANDS - Abstract
A new assemblage of fossil wood of Paleocene age from Seymour Island, Antarctic Peninsula, is described. Conifer species have been identified, belonging to the fossil genera Agathoxylon , Phyllocladoxylon , Protophyllocladoxylon , and Podocarpoxylon. Angiosperm fossil wood species are assigned to Nothofagoxylon , Caldcluvioxylon , and Myrceugenellites. New wood types have been described with possible affinity to Atherospermataceae and Asteraceae (daisy family). A newly identified fossil angiosperm species, Aextoxicoxylon jacksius , has been recorded from Antarctica for the first time. It shares traits with modern Aextoxicon punctatum and other Aextoxicoxylon wood from South America but is considered a separate species due to significant differences in vessel density, ray height, and frequency. This study indicates, in accordance with previous studies that conifers were the most common elements in the Paleocene Antarctic vegetation. In particular, Agathoxylon being the most dominant wood type. Nothofagoxylon was the most common angiosperm wood type. Overall the composition of the Antarctic Paleocene vegetation deduced from the presence of fossil wood resembles that of the modern warm to cool temperate forests of Tasmania, New Zealand and southern South America. Possible upland and lowland forest types have been identified, with the lowland forests likely most similar to the modern mixed cool temperate forests on South Island, New Zealand, and Tasmania. The upland forests were similar to the modern open canopy Araucaria-Nothofagus forests on the high Andes today. • A new assemblage of fossil wood of Palaeocene age from Seymour Island, Antarctic Peninsula. • Two newly identified fossil angiosperm species have been identified. • The Antarctic forests resembled modern warm to cool temperate forests of the Southern Hemisphere. • Upland and Lowland flora's have been distinguished. • Nothofagoxylon and Agathoxylon were the most common wood types. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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30. Unparallel resilience of shallow-water tropical calcifiers (foraminifera and scleractinian reef corals) during the early Paleogene global warming intervals.
- Author
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Benedetti, Andrea, Papazzoni, Cesare A., and Bosellini, Francesca R.
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- *
SCLERACTINIA , *BIOLOGICAL extinction , *PALEOCENE Epoch , *PALEOGENE , *EOCENE Epoch , *CORAL reefs & islands - Abstract
Investigating the fossil record to provide evidence about the response of shallow-water tropical calcifiers to past warming events is crucial considering that they are severely threatened by current global warming. We thus focused our attention on scleractinian reef corals (SRC) and shallow-water foraminifera (SWF), both mainly symbiont-bearing organisms, analysing and comparing their diversity patterns during the Paleocene and Eocene from datasets of the Neothetyan circum-Mediterranean region. In particular, at both genus and species level, we analysed changes in diversity, together with origination and extinction rates. Despite some biases related to biostratigraphic resolution of SRC and SWF data, our results show that they reacted differently to the major warming events of the Early Paleogene. The K/Pg mass extinction caused the disappearance of almost all SWF, whereas several corals passed this crisis and persisted up to the end of Paleocene, when the Paleocene-Eocene Thermal Maximum (PETM) caused a relatively small decrease of coral diversity together with a global collapse of coral reefs. On the other hand, a rapid radiation of nummulitids and alveolinids occurred at species level. The impact of the Early Eocene Climatic Optimum (EECO) was apparently more severe for SWF than for SRC. After the Middle Eocene Climatic Optimum (MECO), the general cooling trend led to the fading of Eocene SWF genera and species, whereas SRC began their rapid diversification from Bartonian to Priabonian and culminating in the Chattian. Our results suggest that rapid warming events favoured speciation in SWF, whereas the slow cooling trend (e.g., after the MECO) favoured diversification of SRC. Our data also underline that SWF reacted differently to warming events as compared to deep-sea smaller benthic foraminifera and that the same events in the planktonic realm are not strictly coeval with those occurring in shallow-water environments. On a wider perspective, we observe that shallow-water calcifiers demonstrate a good degree of resilience to global temperature increases, even if undergoing to more or less marked reduction of biodiversity. We provide evidences for the recovery of past ecosystems from both short and long stressors. • Paleocene-Eocene foraminifera and corals biodiversity is affected by warming events. • The response of foraminifera and corals to the same warming events is different. • Foraminiferal diversity is more susceptible to rapid warming events. • Coral diversity appears less influenced by warming events. • Generally, both groups exhibit quite high resilience to warming events. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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31. Phelodinium fensomei sp. nov.: a protoperidineacean dinoflagellate cyst from the lower Paleocene (Danian) of the Oyster Bay Formation, Vancouver Island, Canada.
- Author
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McLachlan, Sandy M. S.
- Subjects
- *
DINOFLAGELLATE cysts , *PALEOCENE Epoch , *GYMNODINIUM , *DINOFLAGELLATES , *SCANNING electron microscopy , *ULTRAVIOLET radiation , *ISLANDS - Abstract
Phelodinium fensomei is a new species of organic-walled dinoflagellate cyst described from the Appian Way section of the Oyster Bay Formation, Vancouver Island, British Columbia, Canada. Phelodinium fensomei sp. nov. differs from other species of Phelodinium in its unique combination of characters including an elongate epicyst, bilobate endocyst antapex, and microgranulate to verrucate surface ornamentation. The species occurs exclusively within Dinoflagellate Cyst Zone D4 of the Oyster Bay Formation along with the Danian indicator taxon Danea californica. This is also the first study to perform scanning electron microscopy and epifluorescence analysis on a specimen belonging to the protoperidinioid genus Phelodinium, revealing minute features and a negative response to ultraviolet light exposure, indicating a heterotrophic feeding strategy for the motile cell. Although P. fensomei sp. nov. occurs at markedly low relative and absolute abundances in the examined interval, it is restricted to strata of Danian age suggesting potential biostratigraphic utility. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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32. A morphological comparison of two cladopyxidacean dinoflagellates: the extant Micracanthodinium setiferum and the fossil Cladopyxidium saeptum (Dinophyceae, Gonyaulacales).
- Author
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Mertens, Kenneth Neil, Carbonell-Moore, M. Consuelo, and Gardner, Kristina
- Subjects
- *
DINOFLAGELLATES , *EOCENE Epoch , *PALEOCENE Epoch , *FOSSILS , *OCEAN , *GYMNODINIUM , *PLANKTON - Abstract
Among dinoflagellates, extant cladopyxidaceans may provide a missing link to better understand the first evolutionary transformations from ancestral configurations toward the more abundant and more derived patterns in Gonyaulacales and Peridiniales. A restudy of the extant, motile-defined Micracanthodinium setiferum using plankton samples from the Indian and Atlantic oceans and the Mediterranean Sea demonstrates that the correct plate formula is Po, Pt, X, 3′ + *4′, 4a, 7′′, 7C, 4S, ?6′′′, 0p, 2′′′′. A ventral pore is found between 1′, 3′ and *4′. A restudy of the extinct, fossil-defined Cladopyxidium saeptum from the upper Paleocene of Delaware (USA), demonstrated the presence of an identical tabulation. A ventral pore (= porichnion) was positioned between *1′ and 7′′. Cladopyxidium is morphologically closer to Micracanthodinium than to Cladopyxis. Since Cladopyxidium has been extinct since the middle Eocene, it is unlikely that Micracanthodinium and Cladopyxidium have a direct biological link; the close morphological similarity between them does, however, suggest an important phylogenetic relationship between them in the evolution of cladopyxidaceans. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
33. Typification of the genus Zizyphoides Seward et Conway (Magnoliophyta, Trochodendraceae).
- Author
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ZOLINA, ANASTASIA A., MANCHESTER, STEVEN R., and GOLOVNEVA, LINA B.
- Subjects
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ANGIOSPERMS , *PALEOCENE Epoch , *NATIONAL museums - Abstract
Type material of Paliurus colombii Heer, Populus arctica Heer, Hakea arctica Heer, and Hedera macclurii Heer from the Atanikerdluk locality (Paleocene, Greenland) was restudied based on the original collection, stored in the National Museum of Ireland, Dublin. All these species were joined under the name Zizyphoides colombii (Heer) Seward et Conway, type species of the genus Zizyphoides Seward et Conway. A lectotype of Zizyphoides colombii is designated and the diagnosis of this species is emended. An emended diagnosis of the genus Zizyphoides is also presented. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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34. New Skull Material of Taeniolabis taoensis (Multituberculata, Taeniolabididae) from the Early Paleocene (Danian) of the Denver Basin, Colorado.
- Author
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Krause, David W., Hoffmann, Simone, Lyson, Tyler R., Dougan, Lindsay G., Petermann, Holger, Tecza, Adrienne, Chester, Stephen G. B., and Miller, Ian M.
- Subjects
- *
TAENIOLABIDIDAE , *MAMMALS , *PALEOCENE Epoch , *COMPUTED tomography , *PALEOGENE - Abstract
Taeniolabis taoensis is an iconic multituberculate mammal of early Paleocene (Puercan 3) age from the Western Interior of North America. Here we report the discovery of significant new skull material (one nearly complete cranium, two partial crania, one nearly complete dentary) of T. taoensis in phosphatic concretions from the Corral Bluffs study area, Denver Formation (Danian portion), Denver Basin, Colorado. The new skull material provides the first record of the species from the Denver Basin, where the lowest in situ specimen occurs in river channel deposits ~730,000 years after the Cretaceous-Paleogene boundary, roughly coincident with the first appearance of legumes in the basin. The new material, in combination with several previously described and undescribed specimens from the Nacimiento Formation of the San Juan Basin, New Mexico, is the subject of detailed anatomical study, aided by micro-computed tomography. Our analyses reveal many previously unknown aspects of skull anatomy. Several regions (e.g., anterior portions of premaxilla, orbit, cranial roof, occiput) preserved in the Corral Bluffs specimens allow considerable revision of previous reconstructions of the external cranial morphology of T. taoensis. Similarly, anatomical details of the ascending process of the dentary are altered in light of the new material. Although details of internal cranial anatomy (e.g., nasal and endocranial cavities) are difficult to discern in the available specimens, we provide, based on UCMP 98083 and DMNH.EPV 95284, the best evidence to date for inner ear structure in a taeniolabidoid multituberculate. The cochlear canal of T. taoensis is elongate and gently curved and the vestibule is enlarged, although to a lesser degree than in Lambdopsalis. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
35. Early Paleocene Paleoceanography and Export Productivity in the Chicxulub Crater.
- Author
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Lowery, Christopher M., Jones, Heather L., Bralower, Timothy J., Cruz, Ligia Perez, Gebhardt, Catalina, Whalen, Michael T., Chenot, Elise, Smit, Jan, Phillips, Marcie Purkey, Choumiline, Konstantin, Arenillas, Ignacio, Arz, Jose A., Garcia, Fabien, Ferrand, Myriam, and Gulick, Sean P. S.
- Subjects
PALEOCENE Epoch ,PALEOCEANOGRAPHY ,EUPHOTIC zone ,CARBON isotopes ,MASS extinctions ,PALEOGENE ,CALCAREOUS soils - Abstract
The Chicxulub impact caused a crash in productivity in the world's oceans which contributed to the extinction of ∼75% of marine species. In the immediate aftermath of the extinction, export productivity was locally highly variable, with some sites, including the Chicxulub crater, recording elevated export production. The long‐term transition back to more stable export productivity regimes has been poorly documented. Here, we present elemental abundances, foraminifer and calcareous nannoplankton assemblage counts, total organic carbon, and bulk carbonate carbon isotope data from the Chicxulub crater to reconstruct changes in export productivity during the first 3 Myr of the Paleocene. We show that export production was elevated for the first 320 kyr of the Paleocene, declined from 320 kyr to 1.2 Myr, and then remained low thereafter. A key interval in this long decline occurred 900 kyr to 1.2 Myr post impact, as calcareous nannoplankton assemblages began to diversify. This interval is associated with fluctuations in water column stratification and terrigenous flux, but these variables are uncorrelated to export productivity. Instead, we postulate that the turnover in the phytoplankton community from a post‐extinction assemblage dominated by picoplankton (which promoted nutrient recycling in the euphotic zone) to a Paleocene pelagic community dominated by relatively larger primary producers like calcareous nannoplankton (which more efficiently removed nutrients from surface waters, leading to oligotrophy) is responsible for the decline in export production in the southern Gulf of Mexico. Plain Language Summary: The end Cretaceous mass extinction was caused by the impact of an asteroid in what is now the Yucatán Peninsula, México. The impact ejected aerosols and dust into the air that reduced sunlight transmission, causing a severe decline in photosynthesis and the collapse of marine food webs. However, the change in the amount of organic matter created by photosynthesizing plankton that was delivered to the seafloor (export productivity) was variable across the oceans. At some places, including the Chicxulub crater, export productivity was actually high immediately after the impact. We produced a ∼3‐million ‐year record of export productivity in the crater to determine how long it remained elevated and why it eventually declined. Export production was very high for the first 320,000 years after the impact, declined from 320,000 to 1,200,000 years after the impact, and then remained low. We found that this production was not related to the input of nutrients nor the degree of stratification of the ocean, but instead was probably driven by the increase in the cell size of phytoplankton. Larger phytoplankton removed nutrients from the surface waters as they sank, prompting an increase in species which are better adapted to low‐nutrient waters. Key Points: Export productivity at Chicxulub was elevated for 1.2 Myr post K‐Pg; it was very high for the first 0.32 Myr and declined from 0.32–1.2 MyrThe final decline in export productivity ∼0.9–1.2 Myr is associated with the termination of calcareous nannoplankton disaster assemblagesExport productivity change is not correlated with stratification or terrigenous input and was likely driven by changes in the phytoplankton [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
36. Magnetostratigraphy of lower Paleocene strata in the Ferris Formation, Hanna Basin, Wyoming, with refined resolution of the Pu1-Pu2 interval-zone boundary of the Puercan North American Land Mammal Age.
- Author
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Albright III, L. Barry and Eberle, Jaelyn L.
- Subjects
PALEOCENE Epoch ,PALEOMAGNETISM ,CRETACEOUS-Paleogene boundary ,PALEOGENE ,MASS extinctions ,MAMMALS - Abstract
Recent studies of early Paleocene stratigraphic sections across the U.S. Western Interior are refining our understanding of the biotic recovery in the aftermath of the Cretaceous-Paleogene (K-Pg) mass extinction event. Herein we present magnetostratigraphic data from an approximately 600-m-thick section of strata of the Ferris Formation in the Hanna Basin, south-centralWyoming, that spans the K-Pg boundary and includes in conformable superposition the three subdivisions of the earliest Paleocene Puercan North American Land Mammal Age: interval zones Pu1, Pu2, and Pu3. Prior studies on early Paleocene stratigraphic sections in Montana to the north of Hanna Basin and in Colorado and NewMexico to the south have been only marginally successful in defining the temporal boundaries of these divisions. This earlier work typically restricted Pu1 entirely within reversed magnetochron C29r, Pu2 entirely within normal magnetochron C29n, and at least the early part of Pu3 in C29n, as well. Results of the present study confirm what has been only tentatively suggested previously: that interval zone Pu2 begins in the youngest part of C29r, with later Pu2 fauna extending into C29n. Although Pu3 is known to begin in C29n, its younger limit remains unknown in our Hanna Basin section, because the top of the local Puercan is well above the stratigraphic level of our sampling for this project. We estimate a date for the Pu1-Pu2 boundary in the Hanna Basin section of approximately 65.82 Ma--nearly 70 k.y. earlier than prior estimates. This boundary marks the transition from the Pu1 survival fauna to later phases of the mammalian recovery characterized by a significant increase in diversity, appearance of considerably larger-bodied mammals, and greater dental and dietary specializations. [ABSTRACT FROM AUTHOR]
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- 2021
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37. The Paleocene of IODPSite U1511, Tasman Sea: Alagerstätte deposit for deep-water agglutinated foraminifera.
- Author
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Kaminski, Michael A., Alegret, Laia, Hikmahtiar, Syouma, and Waśkowska, Anna
- Subjects
- *
PALEOCENE Epoch , *FORAMINIFERA , *SEDIMENT compaction - Abstract
Deep-water agglutinated Foraminifera (DWAF) are investigated from Paleocene sediments recovered from IODP Hole U1511B in the northeastern Tasman Sea. The recovered foraminifera display exceptional three-dimensional preservation: they are relatively unaltered by sediment diagenesis and compaction. We examined 27 samples fromCores U1511B-45R to -47R, and recovered over 70 species of DWAF. The assemblage consists entirely of "cosmopolitan" forms originally described from the Carpathians, Caucasus, Trinidad, and the western Tethys, implying that there is no provinciality among DWAF faunas in the world ocean. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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38. SEDIMENTOLOGY OF THE PALEOCENE – EARLY EOCENE SEQUENCE, SOUTHWESTERN IRAQ.
- Author
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Tamar-Agha, Mazin Y.
- Subjects
PALEOCENE Epoch ,LITHOFACIES ,SEDIMENTOLOGY ,EVAPORITES ,DOLOMITE ,PALEOGENE ,EOCENE Epoch - Abstract
Copyright of Iraqi Bulletin of Geology & Mining is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
39. Paleocene rotaliid benthic foraminifera of Jabal Mundassa, Al Ain area, United Arab Emirates.
- Author
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Anan, Haidar Salim
- Subjects
FORAMINIFERA ,MICROPALEONTOLOGY ,PALEOCENE Epoch ,INTERTIDAL zonation - Abstract
The micropaleontological taxa of Jabal Mundassa, Al Ain area, United Arab Emirates (UAE) indicates that the Paleocene succession bears prolific and well preserved benthic foraminifera index-species of the Danian, and its succession is considered the only outcrop that has Danian sediments in the Al Ain area, and most complete Danian rocks in UAE. The Danian succession is attributed to the shaley marl neoautochthonous sediments belong to Mundassa Member (MM) of the Muthaymimah Formation (MF), which are unconformably overlying the pre-Maastrichtian allochthonous Semail Ophiolite (SO, serpentinites and serpentinized peridotites). Forty six rotaliid benthic foraminiferal species belonging to twenty six genera are identified from fourteen samples collected from the Paleocene succession of the Mundassa section. Based on the planktic foraminiferal zonation, the duration of the hiatus at the Cretaceous/Paleogene (K/P) boundary includes the two early Danian biozones (P0 and Pa, about 0.02 Ma). This depositional gap is most probably due to submarine erosion (not to subaerial denudation), and correspond to an interval of tectonic activity that exists in most localities in the Middle East and other sites in the world. In current study, an attempt is made to identify the rotaliid Danian calcareous benthic foraminifers of the Mundassa section, and it is possible to illustrate twenty eight of them in two plates (1, 2), for the first time, with some additional remarks on paleontology, stratigraphy and paleogeography in the UAE and other Tethyan localities. [ABSTRACT FROM AUTHOR]
- Published
- 2021
40. Palynology from ground zero of the Chicxulub impact, southern Gulf of Mexico.
- Author
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Smith, Vann, Warny, Sophie, Vellekoop, Johan, Vajda, Vivi, Escarguel, Gilles, and Jarzen, David M.
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- *
PALYNOLOGY , *DINOFLAGELLATE cysts , *POLLEN , *PLANT spores , *FUNGAL spores , *PALEOCENE Epoch , *EOCENE Epoch , *PALEOGENE - Abstract
Palynological analysis of Site M0077A in the Chicxulub impact crater has yielded a record of the immediate Cretaceous/Paleogene (K/Pg) recovery from ground zero of the end-Cretaceous mass extinction, followed by a record of the Paleocene–Eocene Thermal Maximum (PETM) and later Ypresian (Eocene), including the Early Eocene Climatic Optimum (EECO). Eight specimens of the dinoflagellate cyst Trithyrodinium evittii have been observed near the base of the K/Pg transitional unit; these likely represent a post-impact dinoflagellate disaster recovery assemblage deposited within several days following the impact, although the possibility that some or all of the T. evittii specimens are reworked Maastrichtian cysts cannot be fully excluded. Despite high-resolution sampling of the lowermost Paleocene successions, the oldest identifiable terrestrial palynomorphs observed in the Site M0077A core, two specimens of Deltoidospora fern spores, occur at least ∼200,000 years after the impact. Other than these occurrences, the Paleocene section is nearly barren in terms of palynomorphs, likely a result of poor preservation of organic material combined with a long recovery time for vegetation in the vicinity of the crater. Pollen and fungal spore concentrations spike in an anoxic dark shale deposited during the PETM around 56 Ma, with a diverse pollen assemblage indicating the presence of a coastal shrubby tropical forest in the geographic vicinity, likely in the Yucatán Peninsula to the south. In the marine realm, this interval is characterized by thermophilic assemblages of dinoflagellate cysts. Stratigraphically constrained cluster analysis identified four statistically robust sample clusters in the lower Eocene successions, with Malvacipollis spp. and Milfordia spp. abundances driving the highest average dissimilarity between clusters. A second notable spike in palynological concentrations above the PETM section may represent another early Eocene hyperthermal event. Pollen and plant spore concentrations generally increased during the EECO, associated with increases in terrestrial input during basin infilling. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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41. Exceptional avian pellet from the Paleocene of Patagonia and description of its content: a new species of calyptocephalellid (Neobatrachia) anuran.
- Author
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Muzzopappa, Paula, Martinelli, Agustín G., Garderes, Juan P., Rougier, Guillermo W., and Cavin, Lionel
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PALEOCENE Epoch ,BIRDS of prey ,SPECIES - Abstract
A fossil gastric pellet from the Danian 'Banco Negro Inferior' of the Salamanca Formation at Punta Peligro Locality (Chubut, Argentina) and its 3D preserved fossil content is studied herein. The structure of the pellet and the condition of the enclosed bones suggest that it was produced by a bird of prey, although birds of any kind are as yet unknown from osteological remains in the Banco Negro ecosystem. The content of the pellet originated from a single anuran individual, representing a new species of the genus Calyptocephalella, is described herein as C. sabrosa sp. nov. The new find highlights the broad temporal, geographical and taxonomic diversity of this frog genus in Patagonia's geological past. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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42. New earliest Paleocene (Puercan) periptychid 'condylarths' from the Great Divide Basin, Wyoming, USA.
- Author
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Atteberry, Madelaine R. and Eberle, Jaelyn J.
- Subjects
- *
PALEOCENE Epoch , *MOLARS - Abstract
An earliest Paleocene (Puercan) locality in the China Butte Member of the Fort Union Formation in the Great Divide Basin (GDB) of Wyoming contains a diverse mammalian faunal assemblage, including a number of 'condylarth' taxa. From UCM locality 2011035, we describe three new periptychid 'condylarths' and report first occurrences of Maiorana noctiluca, Ampliconus antoni and Conacodon harbourae from the GDB. The new genus and species Miniconus jeanninae is characterized by a ridge-like metaconid and incipient paraconid on p4, and a molar parastylid. Based on its similarity to M. jeanninae and differences from other species of Oxyacodon, O. archibaldi is placed within the new genus Miniconus. A second new genus and species Beornus honeyi is characterized by its large size with inflated premolars and molars, and small molar paraconid. A new species of Conacodon, C. hettingeri, is similar to other species of Conacodon but differs in its m3 morphology. To examine the relationships of the three new GDB taxa to each other and to other Puercan 'condylarths' from the Western Interior of North America, a phylogenetic analysis was performed using 28 Puercan periptychid and arctocyonid taxa as well as the eutherian outgroup taxon Procerberus formicarum and 64 dental characters. The resulting strict consensus tree of 210 steps confirms that the three new species from the GDB fall within Periptychidae. Beornus honeyi forms a polytomy with Mithrandir gillianus and Hemithlaeus kowalevskianus. Conacodon hettingeri is recovered as the basal member of a clade that includes the other species of Conacodon. Miniconus jeanninae is the sister to M. archibaldi. Additionally, the early Puercan Mimatuta spp. and Maiorana noctiluca fall within the Arctocyonidae, supporting the phylogenetic placement of these taxa by other recent analyses. The occurrence of the three new periptychids in the GDB indicates that mammalian diversity is higher than previously suggested for the early Puercan. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
43. Microfacies analysis of the Late Maastrichtian- Danian Phosphatic Succession in the H3-Trebeel district, Western Desert of Iraq.
- Author
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Mousa, Anwar K., Al-Dulaimi, Salam I., and Mohammed, Ibrahim Q.
- Subjects
- *
PALEOCENE stratigraphic geology , *FACIES , *PALEOCENE Epoch , *FORAMINIFERA , *BOREHOLES - Abstract
The Late Maastrichtian–Danian phosphatic succession prevails as a deposit to the west of Rutbah region, Western Iraq. This is manifested through the lithostratigraphic sections of boreholes (K.H5\6 and K.H 5\8) drilled previously in the area. The succession is mainly composed of phosphate, shale, porcelanite, oyster and foraminiferal carbonate lithofacies belonging to Digma and Akashat formations. Three facies associations are distinguished during the study: the phosclast planktonic (FA1) that dominates the outer ramp, the phosclast foraminiferal (FA2) that dominates the mid ramp, and the quartz dolomitic phosclast (FA3) present in the inner ramp. These facies’ associations are differentiated into seventeen microfacies types. Microfacies analysis and fauna contents have shown gradual facies variation grading from a high energy inner ramp environment in the east to a low energy deep water ramp environment in the west. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
44. Phosphate δ13Corg chemostratigraphy from the Gantour basin, Morocco: A proof of concept from the K–Pg transition to mid-Thanetian.
- Author
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Aubineau, Jérémie, Parat, Fleurice, Pierson-Wickmann, Anne-Catherine, Séranne, Michel, Chi Fri, Ernest, El Bamiki, Radouan, Elghali, Abdellatif, Raji, Otmane, Muñoz, Manuel, Bonnet, Clément, Jourani, Es-Said, Yazami, Oussama Khadiri, and Bodinier, Jean-Louis
- Subjects
- *
PROOF of concept , *ANIMAL diversity , *CARBON isotopes , *PALEOCENE Epoch , *ORE deposits , *CHEMOSTRATIGRAPHY , *PALEOGENE - Abstract
The Late Cretaceous–early Paleogene interval is globally associated with transient to long-term changes in the stable carbon isotopic composition of marine carbonates (δ13C carb). Based on biostratigraphic reconstruction, this critical period of Earth's history is thought to coincide with the deposition of world heritage Paleocene phosphate deposits (phosphorites) in northwestern Morocco. However, the detailed stratigraphy of the Gantour basin, one of the most important Moroccan phosphate deposits, has not yet been constrained. For instance, the former "Montian" Stage has been used to tentatively approximate the Danian, whereas the succeeding Selandian Stage remains to be identified. Here, we develop a detailed organic carbon isotopic (δ13C org) curve from phosphorus-rich horizons of the western Gantour sedimentary sequence in an attempt to constrain their stratigraphic placement and depositional age model. Upsection, these strata host long-term negative and positive δ13C org trends that tend to correlate with global δ13C carb records of the Cretaceous–Paleogene and mid-Thanetian transitional boundaries. The data support the presence of Danian and Selandian rocks in the Gantour basin, which are succeeded by strata containing characteristic signatures of the well-known Cenozoic δ13C maximum at 58–57.5 Ma (the Paleocene Carbon Isotope Maximum). Our results shift the previously proposed Cretaceous–Paleogene transition in the Gantour basin further down into the older sediment C2M layer without interfering with recorded massive biological turnover in faunal diversity and abundance. Moreover, the refined stratigraphy suggests that the deposition of the Gantour phosphorites spanned ∼8.5 Myr. Our results confirm the utility of δ13C org chemostratigraphy for dating and correlating phosphate-bearing deposits of the Tethyan province. They have important implications for deciphering Paleocene phosphogenesis, the co-evolution of associated vertebrate groups, and for prospecting phosphorus-rich mineral deposits. • Datation of phosphate-bearing sequences from the Moroccan western Gantour basin. • δ13C org chemostratigraphy is an appropriate correlation tool. • The refined stratigraphy implies at least the presence of Danian, Selandian, and mid-Thanetian rocks. • Phosphate deposition over a ∼ 8.5 Myr long time period. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Maastrichtian – Paleocene environmental and climatic conditions in Koum Basin (northern benue trough, Cameroon) inferred using a multiproxy approach including sedimentology, mineralogy, and geochemistry.
- Author
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Ngo Mandeng, Glwadys, Boboye, Olugbenga A., Bessong, Moïse, and Mbabi Bitchong, André
- Subjects
- *
GEOCHEMISTRY , *MINERALOGY , *PALEOCENE Epoch , *SEDIMENTOLOGY , *FELSIC rocks , *KEROGEN - Abstract
The Koum Basin is one of major intracontinental basins in northern Cameroon. It is part of the Upper Benue Trough and has genetic ties to the West and Central African Rift System. The main purpose of studying the Koum Basin sedimentary deposits was to re-examine the time of the deposition and constrain the palaeoenvironmental and paleoclimatic conditions during deposition. To accomplish this, we used a combination of sedimentologic, palynologic, mineralogic, and geochemical data. Claystone units interbedded with calcareous siltstones dominate sedimentary sequence, including few clay beds, fine to medium-grained sandstone, and rare marl layers. The palynomorph assemblage suggests a previously unknown Maastrichtian – Paleocene age in this basin. The sediments originated from intermediate igneous parent rocks with a relative contribution of felsic rocks. These rocks underwent low detritism (Si/Al: 2.51–4.43; K/Al: 0.11–0.36; Ti/Al: 0.05–0.10) and chemical weathering (CIA: 55–64; PIA: 56–68) in the source region. Consequently, deposits are immature (ICV values > 1) and weakly recycled (Si 2 O 3 /Al 2 O 3 ratios ≤5). The organic matter analysis and the palynoflora assemblage, reveal Type III kerogen with significant contributions of Type II-III and type II kerogens, as well as a continental paleo-depositional environment with open rainforest to savannah vegetation. The clay minerals distribution suggests moderate illitization and chloritization processes and thus moderate burial diagenesis at temperatures ranging from 70 to 90 °C, also attested by immature to mature Tmax values (≤436 °C) marginally. The low CIA values and very low kaolinite contents, indicate dry climatic conditions. In addition, two major-element-based discrimination diagrams show that the parent rocks of clastic sediments formed primarily in a continental arc system, with a moderate contribution from the rift system and a low contribution from the oceanic island arc, implying compressional conditions, which is consistent with previous studies on the tectonic background of the region during the late Maastrichtian to Paleocene period. • The first Maastrichtian – Paleocene record from the Koum Basin, Upper Benue Trough, northern Cameroon. • Illitization and chloritization processes point moderate burial diagenesis, and immature to marginally mature organic matter. • Pollen and spores, clay minerals, and CIA all hint to a semi-arid environment with open rainforest to savannah vegetation. • Compressional tectonic conditions were discovered in the Koum Basin at this period. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Planktic foraminiferal response to an early Paleocene transient warming event and biostratigraphic implications.
- Author
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Bornemann, André, Jehle, Sofie, Lägel, Friederike, Deprez, Arne, Petrizzo, Maria Rose, and Speijer, Robert P.
- Subjects
- *
PALEOCENE Epoch , *NANNOFOSSILS , *CARBON cycle , *ANOXIC zones , *IGNEOUS provinces - Abstract
The Latest Danian Event (LDE, ~ 62.2 Ma) is characterized by global changes in the carbon cycle as indicated by two negative δ13C excursions of up to ~ 1‰. These δ13C shifts are accompanied by a 2–3 °C warming of both surface and deep waters based on benthic and planktic foraminiferal δ18O measurements, and the LDE has, thus, been considered as a so-called hyperthermal event. The event lasted for 200 kyr and has been identified in various ocean basins and shallow marine settings. Here, we present a compilation of data from three deep-sea cores covering the Pacific, North and South Atlantic oceans as well as a southern Tethyan shelf section to document the response of planktic foraminifera assemblages to ocean warming. In all studied successions, we observe the disappearance of the planktic foraminifer genus Praemurica on a global scale that took place close to the onset of the LDE. Moreover, on the long run, praemuricids were contemporaneously replaced by morozovellids. Both the decline of Praemurica and a temperature increase started between 200 and 260 kyr before the LDE onset and were punctuated by the LDE itself. In this paper, we propose two mechanisms that have controlled the environmental changes associated with this event, (1) increased activity of the North Atlantic Igneous Province acting on long time-scales, and (2) changes of orbital parameters resulting in insolation changes on shorter time-scales. In contrast to a proposed muted benthic foraminiferal response, the planktic community has been substantially impacted by the LDE as indicated by changes in planktic foraminifera faunas and calcareous nannofossils. Finally, our quantitative and conventional approaches identifying stratigraphically important planktic foraminifera datum levels justify a revision of the upper Danian to lower Selandian planktic foraminifera biozonation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
47. The Paleogene of the Cis-Donets Monocline and Its Palynological Characteristics.
- Author
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Iakovleva, A. I. and Aleksandrova, G. N.
- Subjects
- *
PALEOGENE , *DINOFLAGELLATE cysts , *OLIGOCENE Epoch , *EOCENE Epoch , *PALEOCENE Epoch - Abstract
The results of the palynological study of the Paleogene and the underlying Cretaceous sediments of the Cis-Donets Monocline, drilled by borehole 1238, are presented. Analysis of dinoflagellate cysts enabled the recognition of the Apectodinium hyperacanthum, Axiodinium augustum, and Ochetodinium romanum/Samlandia chlamydophora zone intervals and the Rhombodinium draco–Deflandrea spinulosa layers in the Paleogene part of the section. The age of regional formations and beds was updated: the Buzinovka Formation is dated by the early Thanetian; the Veshenskaya Formation is late Thanetian–earliest Ypresian age; the Surovikino and Osinovaya Beds are early–middle Ypresian; and the Ventsy and "Poltava" Beds are of the late Rupelian–Chattian age. Two major stratigraphic hiatuses, corresponding to the Maastrichtian–Selandian and the upper Ypresian–lower Rupelian, were recognized in the borehole 1238 section. The analysis of the quantitative fluctuations of different palynomorph groups through the section permitted to reconstruct changes in depositional environments of the Peri-Tethys Basin margin during the early and late Paleogene: the Buzinovka and Veshenskaya formations and the Surovikino and Osinovaya Beds were accumulated in an open-marine environments during the long late Paleocene–early Ypresian transgressive stage, whereas the Ventsy and "Poltava" beds were deposited in the half-landlocked basin during the Chattian. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
48. On the genus Vanikoropsis Meek, 1876 (Gastropoda, Caenogastropoda) from the Paleocene of Denmark and West Greenland with descriptions of three new species.
- Author
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SCHNETLER, KAI INGEMANN and NIELSEN, MOGENS STENTOFT
- Subjects
- *
PALEOCENE Epoch , *NEOGASTROPODA , *GASTROPODA , *SPECIES , *MARL , *PALEOGENE , *BOULDERS - Abstract
The predominantly Cretaceous gastropod genus Vanikoropsis Meek, 1876 is represented in the Paleocene of Denmark and West Greenland by four species, of which three are established herein as new, viz. Vanikoropsis mortenseni n. sp., Vanikoropsis (s.l.) jakobseni n. sp. and Vanikoropsis (s.l.) bashforthi n. sp. The Danish species was found in a boulder of Kerteminde Marl (Selandian, middle Paleocene) from Gundstrup, while the species from West Greenland were found in the localities Sonja Lens and Qaarsutjagerdal on the Nuussuaq peninsula (late Danian, early Paleocene). The Danish species extends the stratigraphic range of the genus into the middle Paleocene and supports the affinities of the Kerteminde Marl fauna to the Paleocene fauna of West Greenland. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
49. A tale from the middle Paleocene of Denmark: A tube-dwelling predator documented by the ichnofossil Lepidenteron mortenseni n. isp. and its predominant prey, Bobbitichthys n. gen. rosenkrantzi (Macrouridae, Teleostei).
- Author
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SCHWARZHANS, WERNER, MILÀN, JESPER, and CARNEVALE, GIORGIO
- Subjects
- *
PALEOCENE Epoch , *OTOLITHS , *FORAGE fishes , *FOSSILS , *PREDATORY animals , *OSTEICHTHYES , *HOMINIDS - Abstract
The ichnofossil Lepidenteron provides a unique taphonomic window into the life habits of a tube-dwelling predator, probably an eunicid polychaete, and its fish prey. Here we describe a new tube-like ichnofossil Lepidenteron mortenseni n. isp. from the Kerteminde Marl (100-150 m palaeo-water depth) from the Gundstrup gravel pit near Odense, Fyn, Denmark. 110 individual tubes were examined which contain fish remains, including a variety of disarticulated bones and otoliths, by far dominated by a single gadiform taxon referred herein to as Bobbitichthys n. gen. The isolated otoliths here associated with disarticulated gadiform bones have previously been described, from the time equivalent Lellinge Greensand exposed in the Copenhagen area, as Hymenocephalus rosenkrantzi, a grenadier fish (family Macrouridae). The abundance of associated bones and otoliths in the examined tubes allowed us to reconstruct part of the cranial configuration of Bobbitichthys rosenkrantzi and to tentatively interpret it as a stem macrourid. Bobbitichthys rosenkrantzi represents the earliest grenadier known in the fossil record. Additional, although considerably less abundant, skeletal remains and otoliths have been tentatively referred to a long-fin bonefish (family Pterothrissidae, Pterothrissus? conchaeformis), a viviparous brotula (family Bythitidae, Bidenichthys? lapierrei), a conger eel (family Congridae, possibly belonging to Rhynchoconger angulosus), and another unidentified gadiform. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
50. Paleocene Larger Foraminifera from the Pyrenean Basin with a recalibration of the Paleocene Shallow Benthic Zones.
- Author
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Serra-Kiel, J., Vicedo, V., Baceta, J. I., Bernaola, G., and Robador, A.
- Subjects
- *
PALEOCENE Epoch , *BENTHIC zone , *PALEOGENE , *TURBIDITES , *FORAMINIFERA - Abstract
A taxonomic study of the Paleocene larger foraminifera from the Pyrenean basin has led to the description of sixty taxa including two new species: Alveolina korresensis and Valvulineria bacetai. In this work, we present a chronostratigraphic recalibration of the Paleocene Shallow Benthic Zones SBZ 1 to SBZ 4 based on correlation with calcareous nannofossil and planktic foraminifera biozones, all integrated within the stratigraphic framework of Paleocene platform to basin depositional sequences established for the whole Pyrenean domain. The samples were collected in autochtonous and parautochtonous deposits from ten key stratigraphic sections, representative of coastal to platform margin depositional settings. The results from two sections representing base of slope facies with intercalations of calcareous turbidites, which include penecontemporaneous platform-derived biota have been integrated in the study. The regional chronostratigraphic framework is derived from magneto-biochronological studies carried out in the Zumaia section, the global reference section for the Danian-Selandian and Selandian-Thanetian GSSPs. A new calibration of the Paleocene SBZs is proposed. The SBZ 1 is constrained to the first 1.09m.y. of the Paleocene; this first Paleogene biozone lacks distinct larger foraminiferal markers and thus is defined by an association of non-exclusive taxa composed of Valvulineria patalaensis, Stomatorbina? binkhorsti, Planorbulina? antiqua and Bangiana hanseni. The SBZ 2 now appears as the biozone encompassing most of the Danian stage (from ca. 64.9m.a. to 61.6m.a.), and is characterized by the association of Haymanella elongata, Haymanella paleocenica, Kayseriella decastroi, Rotospirella conica, Pyrenerotalia depressa, Elazigina dienii, Ornatononion moorkensii and Paralockhartia eos. The SBZ 2-SBZ 3 boundary coincides with the base of the Selandian stage (ca. 61.6m.a.). The SBZ 3 biozone is defined by the occurrence of Glomalveolina primaeva, Periloculina slovenica, Vania anatolica, Coskinon rajkae, Fallotella alavensis, Cribrobulimina carniolica, Miscellanea yvettae, Miscellanea juliettae, Miscellanites primitivus, Miscellanites minutus, Ranikothalia soldadensis, "Operculina" heberti and Discocyclina seunesi. The SBZ 3-SBZ 4 boundary is now ascribed to ca. 57.2m.a. The SBZ 4 biozone appears characterized by Glomalveolina levis, Alveolina korresensis, Hottingerina lukasi, Daviesina garumnensis, Assilina yvettae, Assilina azilensis and Nummulites catari. The SBZ 4-SBZ 5 boundary is placed at the Paleocene-Eocene boundary event (ca. 56.0m.a.). [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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