New early Eocene tapiromorph perissodactyls from the Ghazij Formation of Pakistan, with implications for mammalian biochronology in Asia

Early Eocene mammals from Indo-Pakistan have only recently come under study. Here we describe the first tapiromorph perissodactyls from the subcontinent. Gandheralophus minor n. gen. and n. sp. and G. robustus n. sp. are two species of Isectolophidae differing in size and in reduction of the anterior dentition. Gandheralophus is probably derived from a primitive isectolophid such as Orientolophus hengdongensis from the earliest Eocene of China, and may be part of a South Asian lineage that also contains Karagalax from the middle Eocene of Pakistan. Two specimens are referred to a new, unnamed species of Lophialetidae. Finally, a highly diagnostic M3 and a molar fragment are described as the new eomoropid chalicothere Litolophus ghazijensis sp. nov. The perissodactyls described here, in contrast to most other mammalian groups published from the early Eocene of Indo-Pakistan, are most closely related to forms known from East and Central Asia. Tapiromorpha are diverse and biochronologically important in the Eocene there and our results allow the first biochronological correlation between early Eocene mammal faunas in Indo-Pakistan and the rest of Asia. We suggest that the upper Ghazij Formation of Pakistan is best correlated with the middle or late part of the Bumbanian Asian Land-Mammal Age, while the Kuldana and Subathu Formations of Pakistan and India are best correlated with the Arshantan Asian Land-Mammal Age

Searching for the Terrestrial Paleocene/Eocene Boundary at the Canadian High Arctic: A Carbon Isotope Study

The Paleocene Eocene Thermal Maximum (PETM) is a rare climatic event in the history of the Earth, which marks the abrupt transition from the Paleocene to Eocene of the Cenozoic era with a rapid increase in global surface temperatures of up to 5-8&#;C. The PETM marks the warmest climates in the past 65 million years and a world-wide negative excursion of stable carbon isotopes (δ13C). To determine the location of the Paleocene-Eocene (P/E) boundary in high-latitudinal non-marine strata and to examine the magnitude of vegetation and climatic change during the warming period, the bulk carbon isotope ratios were measured in coal samples taken from several well exposed outcrops at Stenkul Fiord, Ellesmere Island, Nunavut, Canadian Arctic Archipelago. The stratigraphic sections consist of three vertical sequences (SF-P, SF-M, and P Series) that have an approximate total thickness of 74.27 m, 73.18 m, and 145 m respectively. Extending from the lower part of the P-series outcrop, three horizontal sections were taken (1, 2, and 3 Series) each spanning approximately 1 km. The bulk δ13C in the samples ranged from -23.9‰ to -28.7‰ with a background fluctuation of less than 2‰. The PETM boundary is placed in the upper portion of the P-Series between P-58 and P-60 and also in the lower portion of the SF-M and SF-P series where a sharp decrease of δ13C of up to 4.7‰ is detected. This may provide an explanation for the differing conclusions drawn from a recent palynological study and a previously published record from the same sequence. Because the C isotope measurements were based upon Metasequoia-dominated plant matter, the variation of δ13C along the vertical sequence should reflect the change of δ13C of ancient atmospheric CO2, whereas the reduced variation of δ13C in the horizontal sequences may be due to compositional differences of ancient vegetation. This study is the first isotopically marked PETM in high latitude terrestrial outcrops from the High Artic that provides a stratigraphic framework under which the mechanism of drastic climatic change and its impact on non-marine environment can be further investigated.The Paleocene Eocene Thermal Maximum (PETM) is a rare climatic event in the history of the Earth, which marks the abrupt transition from the Paleocene to Eocene of the Cenozoic era with a rapid increase in global surface temperatures of up to 5-8&#;C. The PETM marks the warmest climates in the past 65 million years and a world-wide negative excursion of stable carbon isotopes (δ13C). To determine the location of the Paleocene-Eocene (P/E) boundary in high-latitudinal non-marine strata and to examine the magnitude of vegetation and climatic change during the warming period, the bulk carbon isotope ratios were measured in coal samples taken from several well exposed outcrops at Stenkul Fiord, Ellesmere Island, Nunavut, Canadian Arctic Archipelago. The stratigraphic sections consist of three vertical sequences (SF-P, SF-M, and P Series) that have an approximate total thickness of 74.27 m, 73.18 m, and 145 m respectively. Extending from the lower part of the P-series outcrop, three horizontal sections were taken (1, 2, and 3 Series) each spanning approximately 1 km. The bulk δ13C in the samples ranged from -23.9‰ to -28.7‰ with a background fluctuation of less than 2‰. The PETM boundary is placed in the upper portion of the P-Series between P-58 and P-60 and also in the lower portion of the SF-M and SF-P series where a sharp decrease of δ13C of up to 4.7‰ is detected. This may provide an explanation for the differing conclusions drawn from a recent palynological study and a previously published record from the same sequence. Because the C isotope measurements were based upon Metasequoia-dominated plant matter, the variation of δ13C along the vertical sequence should reflect the change of δ13C of ancient atmospheric CO2, whereas the reduced variation of δ13C in the horizontal sequences may be due to compositional differences of ancient vegetation. This study is the first isotopically marked PETM in high latitude terrestrial outcrops from the High Artic that provides a stratigraphic framework under which the mechanism of drastic climatic change and its impact on non-marine environment can be further investigated

Eocene Amynodonts from Southern California

Introduction.-Since the description [1] of a skull of Amynodontopsis bodei and of a lower jaw referred to this species from the uppermost Eocene, further dental parts have become available for study from localities in the Sespe. These furnish additional characters of value in recognizing the species represented in western Eocene deposits. Now also available is a fragment of skull with cheek-teeth from the Poway Eocene of San Diego County, California. This specimen possesses special significance because it permits a comparison with related forms in America and China. It is likewise of interest because it differs from the amynodonts of the Sespe and is clearly an earlier type

Oxygen isotopic paleotemperatures across the Runangan-Whaingaroan (Eocene-Oligocene) boundary in a New Zealand shelf sequence

Oxygen isotopic compositions of the tests of mainly benthic foraminifera, from sections of conformable Late Eocene (Runangan) to Early Oligocene (Whaingaroan) shelf mudstones, at both Cape Foulwind and Port Elizabeth, western South Island, indicate that shelf sea paleotemperatures followed the global open-ocean trend towards a Paleogene minimum near the Eocene-Oligocene boundary. Throughout the latest Eocene, temperatures declined steadily by 3°C, showed a temporary minor warming at the Eocenc-Oligocene boundary, dropped sharply by 2°C in the Early Oligocene, and ameliorated significantly later in the Early Oligocene. The qualitative temperature trends for New Zealand shelf waters at this time are similar to those inferred from earlier paleontologic syntheses and limited oxygen isotopic work, but involve a range of temperatures within the warm and cool temperate climatic zones and an absolute temperature depression across the Eocene-Oligocene boundary of only 5°C from about 17 to 12°C. Results are consistent with isotopic paleotemperatures determined from deep-sea sediment cores south of New Zealand where the cooling is inferred to mark the onset of production of Antarctic bottom waters at near-freezing temperatures

Primer Frenguelliidae (Insecta: Odonata) del Eoceno de Río Pichileufú, Patagonia, Argentina

Se describe un nuevo género, Treintamilun gen. nov., basado en Treintamilun vuelvenlucha sp. nov. de la localidad de Río Pichileufú (Luteciano), Provincia de Río Negro, Patagonia, Argentina. El nuevo género se asigna a Frenguelliidae. El hallazgo de un segundo género y tercera especie de Frenguelliidae es digno de mención, contribuyendo a un mejor conocimiento de esta pequeña familia y confirma su presencia en el Eoceno de la Patagonia. Mientras las especies previamente registradas de Frenguelliidae son del Ypresiano (52 Ma) de Laguna del Hunco, la nueva especie viene de la localidad vecina a 160 Km y con una edad de 48 Ma. Los Frenguelliidae comparten un surco nodal reducido, una ScP llegando al margen alar muy oblicua al nodus, una Cr nodal subvertical y un nodus vertical, y uno de los caracteres aparentes del plan básico de los Epiproctophora, una CuP curvada. Palabras clave: Odonata, Frenguelliidae, Treintamilun vuelvenlucha gen. nov. et sp. nov., Luteciano, Patagonia, Argentina.A new genus, Treintamilun gen. nov., based on Treintamilun vuelvenlucha sp. nov. is described from Río Pichileufú (Lutetian), Río Negro province, Patagonia, Argentina. The new genus is assigned to Frenguelliidae. The finding of a second genus and third species of Frenguelliidae is noteworthy, contributing to the better knowledge of this little known family and bear out its presence in the Eocene of Patagonia. While the previous species of Frenguelliidae were recorded from the Ypresian (52 Ma) of Laguna del Hunco, the new one comes from the neighbour locality 160 Km far and 48 Ma old. The Frenguelliidae share a nodal furrow reduced, a ScP reaching costal margin very obliquely at nodus, a nodal Cr sub-vertical and subnodus vertical, and one of the groundplan apparent characters of the Epiproctophora, a curved CuP.Fil: Petrulevicius, Julian Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentin

Angiosperm pollen grains from the Cuayuca Formation (Late Eocene to Early Oligocene), Puebla, Mexico

Systematic descriptions and illustrations of the best preserved angiosperm pollen grains (Monocotyledonae or Liliopsida: n= 7 and Dicotyledonae or Magnoliopsida: n= 41) recovered from Cuayuca Formation (late Eocene-early Oligocene), Puebla State, Mexico are provided, some of them of chronostratigraphic importance (Aglaoreidia pristina, Armeria, Bombacacidites, Corsinipollenites, Eucommia, Favitricolporites, Intratriporopollenites, Lymingtonia, Magnaperiporites, Malvacipollis spinulosa, Margocolporites aff. vanwijhei, Momipites coryloides, Momipites tenuipolus, Mutisiapollis, Ranunculacidites operculatus, and Thomsonipollis sabinetownensis). Taxa identified from the Cuayuca Formation suggest local semiarid vegetation such as tropical deciduous forest, chaparral, grassland, and arid tropical scrub, in which angiosperms are one of the main representatives. Nevertheless, temperate taxa from Pinus forest and cloud forest were also registered from regional vegetation. It is noticeable that at the present time, such taxa are well represented in the vegetation of the Balsas River Basin, which would suggest the existence of this type of flora in the Cuayuca region since the Oligocene.Fil: Ramirez Arriaga, Elia. Universidad Nacional Autónoma de México. Instituto de Geología. Departamento de Paleontología; MéxicoFil: Pramparo, Mercedes Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Martínez Hernández, Enrique. Universidad Nacional Autónoma de México. Instituto de Geología. Departamento de Paleontología; Méxic

Sedimentation and subsidence history of the Lomonosov Ridge

During the first scientific ocean drilling expedition to the Arctic Ocean (Arctic Coring Expedition [ACEX]; Integrated Ocean Drilling Program Expedition 302), four sites were drilled and cored atop the central part of the Lomonosov Ridge in the Arctic Ocean at ~88°N, 140°E (see Fig. F18 in the "Sites M0001–M0004" chapter). The ridge was rifted from the Eurasian continental margin at ~57 Ma (Fig. F1) (Jokat et al., 1992, 1995). Since the rifting event and the concurrent tilting and erosion of this sliver of the outer continental margin, the Lomonosov Ridge subsided while hemipelagic and pelagic sediments were deposited above the angular rifting unconformity (see Fig. F7A in the "Sites M0001–M0004" chapter).The sections recovered from the four sites drilled during Expedition 302 can be correlated using their seismic signature, physical properties (porosity, magnetic susceptibility, resistivity, and P-wave velocity), chemostratigraphy (ammonia content of pore waters), lithostratigraphy, and biostratigraphy. The lithostratigraphy of the composite section combined with biostratigraphy provides an insight into the complex history of deposition, erosion, and preservation of the biogenic fraction. Eventually, the ridge subsided to its present water depth as it drifted from the Eurasian margin. In this chapter, we compare a simple model of subsidence history with the sedimentary record recovered from atop the ridge

Paleocene orthophragminids from the Lakadong Limestone, Mawmluh Quarry section, Meghalaya (Shillong, NE India). Implications for the regional geology and paleobiogeography

The late Paleocene orthophragminids, hitherto poorly known from the Himalayan foreland basins, are studied from the Lakadong Limestone in Meghalaya, northeastern India, in order to establish a systematic, biostratigraphic, and paleobiogeographical framework for them in the eastern Tethys. In the Mawmluh Quarry section (MQS) on the Shillong Plateau, to the southeast of Tibet, orthophragminids are associated with typical Paleocene orbitoidiform taxa endemic to the Indian subcontinent, i.e., Lakadongia Matsumaru & Jauhri ( D Setia Ferràndez-Cañadell) and Orbitosiphon Rao, and various species of alveolinids, miscellaneids, and rotaliids, characterizing the Shallow Benthic Zones (SBZ) 3 and 4. The orthophragminids belong to two lineages of the genus Orbitoclypeus Silvestri: O. schopeni (Checchia-Rispoli) and O. multiplicatus (Gümbel), both well known from the peri-Mediterranean region and Europe (western Tethys). The latter species is identified here for the first time from the eastern Tethys. Previous records of the genus Discocyclina Gümbel from the Lakadong Limestone actually correspond to misidentified Orbitoclypeus; this implies that the late Paleocene orthophragminid assemblages from Meghalaya and eastern Tethys were less diverse than in the western Tethys. The lineage of Orbitoclypeus schopeni in the lower part of the Lakadong Limestone (SBZ 3) is identified as O. schopeni cf. ramaraoi based on the morphometry of a few specimens, whereas in the upper part (SBZ 4) it corresponds to a transitional development stage between O. schopeni ramaraoi and O. schopeni neumannae (with average Dmeanvalues ranging between 192 and 199 μ m). The embryon diameters of O. multiplicatus, recorded only in SBZ 4, range between 300 and 319 μ m on average, corresponding to transitional development stages of O. multiplicatus haymanaensis and O. multiplicatus multiplicatus. Our data, along with a review of previous Paleocene and Eocene records from India and Pakistan, suggest that Orbitoclypeus is the only orthophragminid in the Paleocene of the eastern Tethys, whereas Discocyclina first appears in early Eocene times, being mainly represented by endemic taxa confined to the Indian subcontinent. Facies change in the MQS from a marine to continental setting within SBZ 4 corresponds to the oldest record from the Indian plate in the Paleogene, which may be linked to the flexural uplift of the passive margin of the Indian plate, marking the onset of the collision of the Indian and Eurasian plates

Gravity-flow dominated sedimentation on the Buda paleoslope (Hungary): Record of Late Eocene continental escape of the Bakony unit

The Upper Eocene sequence of the Buda Hills consists of fluvial and shallow marine conglomerates, sandstones, bioclastic shallow-water limestone, marlstone and pelagic Globigerina marl. The succession illustrates rapid, overall subsidence of the area, from terrestrial environments to bathyal depths. Sedimentation occurred on slopes situated on the flanks of synsedimentary basement antiforms. Vertical growth of antiforms caused progressive tilting of beds, layerparallel extension by boudinage and faulting, and induced redeposition by mass flow. Antiforms are localised in the dextral Budaörs shear zone and in the Buda imbricate stack, which accommodated the dextral displacement. The latter is underlain by blind reverse faults probably merging into a detachment tault at shallow depths. These structures were formed by WNW-ESE oriented compression and NNE-SSW directed tension. The morphological expression of the imbricate stack is the SE-facing Buda slope. The Bakony unit, while "escaping" from the Alps, was bordered by a northern sinistral and a southern dextral shear zone. Synsedimentary tectonics in the Buda Hills demonstrates the style of deformation inside the escaping block, close to the southern border zone. Tectonically controlled sedimentation suggests that escape tectonics was active as early as Late Eocene time