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Potwar Basin is one of the hydrocarbon prolific basins but pertains complex deformational style. Maximum production has been taken from Paleocene and Eocene carbonates but deeper reservoirs like Cambrian (Khewra sandstone) and Permian (Tobra formation) are also well producing. Geology of the Northern Potwar deformed zone (NPDZ) is mainly controlled by Pre-Cambrian salt, gently dipping basement and its warp. As we move towards south, salt thickness decreases near the axis of Soan syncline, north of Dhurnal structure. Eastern part of NPDZ is buried one while an emergent fold and thrust front (fault propagating fold) in the western part of NPDZ. Eastern NPDZ has duplex structure with initiation of roof thrust from the Murree Formation and sole thrust from Pre-Cambrian salt. The Southern Potwar platform zone (SPPZ) is less disturbed in comparison with NPDZ in which Pre-Cambrian salt acts as a decollement/lubricating surface over which the Cambrian to Pliocene sequence slides as a single thrust sheet. Due to the combined effect of thick overburden of ~3‒5 km and the decollement, folding and thrusting is significant in the Potwar Basin. In the eastern SPPZ, pop-up and fault propagating folds are prominent while in the western SPPZ, triangular zones, pop-up or detachment folds are significant. [ABSTRACT FROM AUTHOR]

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

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

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

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

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

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

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

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]

To reconstruct the paleoclimate in North Africa during the Paleocene, the calcareous nannofossils were quantitatively analyzed at higher resolution from the stratigraphic succession of Gebel Nezzazat (west central Sinai, Egypt). The studied interval extends from NP4 to NP8. Zone NP4 can be subdivided into four subzones from base to top: NTp7B, NTp8A, NTp8B, and NTp8C. The base of the Selandian age is located at the base of NTp8B (Second Radiation of Fasciculithus). The Selandian/Thanetian boundary (S/T) is tentatively placed at the base of Zone NP7/8. The identified nannofossil zones were compared with that of the Tethyan region for the Danian/Selandian boundary. The calcareous nannofossil assemblages were used as indicators for medium-term climatic fluctuations. The pre-Danian (LDE) is dominated by the cool-water Zeugrhabdotus sigmoides and Neochiastozygus modestus, while the post-Danian interval is dominated by Coccolithus pelagicus and Ericsonia subpertusa. Before the onset of the Selandian-Thanetian boundary, a marked shift in the nannofossil species was observed, where Fasciculithus increased significantly, while marker Danian-Selandian genera (e.g., Lithoptychius Neochiastozygus, Chiasmolithus, and Cruciplacolithus) decreased dramatically. Non-Metric Multidimensional Scaling (nMDS) and permutational analysis of variance (PERMANOVA) in addition to the Temperature and Nutrient indices (TI and NI) indicated a marked difference between the warm eutrophic nannofossil assemblages at the Danian/Selandian (D/S) and the Selandian/Thanetian (S/T) transitions and the eutrophic cold-water assemblages during the background sedimentation. A sharp increase in sea surface temperature and decrease in nutrients was observed at D/S and represents the Latest Danian Event (LDE), while the second warming event was started prior to the Selandian and may represent the Early Late Paleocene Event "ELPE." The sea-level lowstand may have limited water circulation, where surface water fertility decreased significantly. Consequently, nannofossil diversity decreased. The rapid recovery after the LDE was attributed to the radiation of warm-water taxa. [ABSTRACT FROM AUTHOR]

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

This study presents a detailed petrophysical characterization of bioturbated reservoir facies retrieved from well L5 of the most oil-productive third-member Paleocene Funing Formation (E1f3). Two siltstones and two sandstone reservoir facies (Rf1, Rf2, Rf3, and Rf4), respectively, are tested and analyzed using petrographic, pressure decay porosimetry, pulse decay permeametry, and TOC techniques. The results indicate that Rf1 (fine-grained, light gray siltstone) is intensely bioturbated (BI = 5; 91–99 vol.%) by Palaeophycus and Taenidium and shows a 64.02% increment in burrow porosity. Rf2 (fine-grained, light gray siltstone) is intensely bioturbated (BI = 5; 91–99 vol.%) by Ophiomorpha, Planolites, and Taenidium with 34% porosity. Rf3 (fine-grained, brown sandstone) is intensely bioturbated (BI = 5; 91–99 vol.%) by Rhizocorallium and Taenidium and indicates a 49.6% burrow porosity increment. Rf4 (fine-grained, brown sandstone) is intensely bioturbated (BI = 5; 91–99 vol.%) by Ophiomorpha, Palaeophycus, and Taenidium with a marginal 4.36% porosity gain. Burrows permeability in all reservoir facies samples improves by approximately 59%, 38%, 52%, and 15%, respectively. The harmonic mean of permeability (vertical fluid flow) best describes the bulk permeability of all reservoir facies. The effects of organic matter (OM) on porosities of Rf1 (0.59% ≤ TOC ≤ 0.76%), Rf2 (0.66% ≤ TOC ≤ 0.98%), Rf3 (0.03% ≤ TOC ≤ 0.05%), and Rf4 (0.04% ≤ TOC ≤ 0.08%) show that OM-hosted porosity is controlled by emplacement of organic matter in Rf2, Rf3, and Rf4 but the removal of organic matter in Rf1. Bioturbation influences porosity, permeability, and TOC, combined with depositional factors such as sorting, grain size distribution, mud-matrix/burrow content, and organic matter-hosted porosity. [ABSTRACT FROM AUTHOR]

NNW‒SSE-trending Jacobabad‒Khairpur High (JKH) is a part of Sukkur rift zone in the Lower Indus Basin (Pakistan), and it evolved during Jurassic rifting when Indian Plate separated from Australian‒Antarctic Plate. At that time, fractures developed due to the upwelling of magma which resulted in the development of detached blocks which dropped relatively to the other ones. Jacobabad‒Khairpur High represents one of those blocks which maintained its original position. This study works out the causes of failure of exploration wells drilled at and in the vicinity of Jacobabad‒Khairpur High (JKH), and comprehends the tectonics, structural trends, and subsurface geology of the region to delineate role of JKH in distribution of source, reservoir and seal rocks for future prospects. This work is based on construction of stratigraphic cross-sections along and across Jacobabad‒Khairpur High, isopach and depth maps to delineate paleo- and present shapes of JKH and its impacts on the petroleum system of the region. This study indicates that Jacobabad‒Khairpur High developed in three stages from Jurassic to Early Eocene. Initially, JKH developed after the deposition of Middle Jurassic Chiltan Limestone and remained uplifted. This interpretation is supported by the absence of main source rocks ‒ Cretaceous Sembar Formation, of the basin on the northern and southern crest of the Jacobabad‒Khairpur High and absence of entire Cretaceous succession on the northern part of the JKH indicating subaerial conditions. Moreover, Cretaceous reservoir rocks—Lower Goru Sand, is also absent in the northern portion of the Jacobabad‒Khairpur High as Paleocene Dunghan Formation is directly overlying the Chiltan Limestone. Furthermore, due to absence of marl and shale of Upper Cretaceous Goru Formation (seal rocks) proper seals are absent in the area. It resulted in the dry holes like Kandra-01, Khairpur-01, Khairpur-02 and Jhatpat-01. However, rocks of petroleum system were deposited all around Jacobabad‒Khairpur High. At the same time, presence of Cretaceous source (Sembar Formation), reservoir (Lower Goru Sand) and seal (Goru Shale) rocks around Jacobabad‒Khairpur High resulted in many discoveries of oil and gas in the Middle and Lower Indus Basin. The Jacobabad‒Khairpur High submerged again during Paleocene when the Indian Plate passed over Kerguelen Hot Spot and became a part of the carbonate shelf to deposit Dunghan Formation over Chiltan Limestone in the northern part of the high. Finally, the Jacobabad‒Khairpur High again reactivated and uplifted to the present position, after the deposition of early Eocene Ghazij Formation when Indian Plate collided with Eurasian Plate. [ABSTRACT FROM AUTHOR]

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

Abstract—The paper demonstrates the possibility of application of the 143Nd/144Nd–Sm/Nd and Nb/Y–Zr/Y diagrams to systematics of basic–ultrabasic complexes of different age: Paleozoic Kalinovsky, Cambrian Sergeevsky and Vladimiro-Aleksandrovsky, and Jurassic and Paleocene ones. The position of data points of the Kalinovsky, Sergeevsky, and Vladimiro-Aleksandrovsky complexes in the diagrams indicates their derivation from a primitive mantle-type (BSE) source, the derivatives of which are frequently associated with Cu, Ni, Co, and PGE mineralization. The position of data points of metabasic rocks of the Avdokimovsky complex and peridotite rocks of the Dalny Kut massif in these diagrams suggests that they have originated from depleted mantle and are promising for the discovery of PGE-bearing chromite mineralization. Data points of Paleocene explosive structures of Sikhote-Alin in the Nb/Y–Zr/Y diagram fall on the trend of recycled crust as a source. This explains the alkaline (to subalkaline) type of magmatism and the high gas saturation of magmas. The explosive structures resemble lamproite pipes, while their rocks are geochemically and mineralogically close both to lamproites and kimberlites. [ABSTRACT FROM AUTHOR]

The outcrop investigations provide a better comprehension to interrelate facies-diagenesis and fracture networks for the evaluation of reservoir potential of the carbonate rocks. In this paper, we targeted Kahi-Section (Nizampur Basin) and Peeran Tangai-Section (Kalachitta Range) to analyze structural-kinematics, Discrete Fracture Network Modelling, microfacies identification and diagenesis to interpret their impact on reservoir potential of Lockhart Limestone (Paleocene). The structural grain within the study area mostly represents the typical east-west trending tight to overturned folds and north-dipping thrust faults that mimic the north-south Indo-Eurasian collision. However, a second phase of deformation related to east-west compressions also identified which rotated the axes of preexisting structures. Fracture analysis revealed that extensional fractures are oriented at high angle to bedding and are differentiated into three orthogonal sets trending northeast-southwest, northwest-southeast and east-west, whereas, the shear fractures formed two conjugate sets trending northeast-southwest. The Lockhart Limestone was deposited in the inner ramp setting and microfacies types are packstone, wackestone and wacke-packstone with seven sub-microfacies types. It has been identified that the Lockhart Limestone has the heterogeneous distribution of diagenetic and tectonic features throughout its extent. The observed diagenetic sequence is micritization, calcite cementation, dissolution, neomorphism, pyritization and compaction. The results highlight that open and partially filled fractures may provide an interconnected network to promote fluid mobility, leading to higher values of fracture permeability. The porosity values of the pore matrix were greater than fracture, resulting a significant impact on reservoir storage capacity. In contrast, a negative impact on reservoir potential has been shown by stylolites, veins and dissolution seams. However, based on the overall studies, the Lockhart Limestone revealed the prospect of a good reservoir unit in the study area. [ABSTRACT FROM AUTHOR]

A palynological assemblage, which was identified during micropaleontological study of the oldest Cenozoic sedimentary cover of the Sea of Japan found at the Yamato Rise, allowed the substantiation of the late Paleocene (59.2–56.0 Ma) age of host deposits. The findings of only marine microfossils in these deposits, the high values of paleosalinity indicators (B, B/Ga), the chemical composition of authigenic minerals, as well as the presence of organic aggregates similar to marine algae, prove a marine genesis of these deposits. It is suggested that sedimentation occurred at the periphery of an epicontinental shallow marine basin under a subtropical climate. [ABSTRACT FROM AUTHOR]

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

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

The research work involves rock physics modeling and reservoir characterization of Suliman fold belt to sulamain fold depression. This area is a brighter zone for hydrocarbon exploration there are several discoveries of gas reserves in this area but there is still needed to estimate seismic characteristics of reflection amplitude properly for further discoveries. Therefore, in this research work we have estimated amplitude offset, inverse quality factor and reservoir characterization of Cretaceous and Paleocene strata of Dhodak-01 & 05, Savi Ragha-01 wells lie in Sulaiman fold belt and Litra formation of Ramak-01 well lie in Sulaiman Depression. To identify the production and reservoir zones. Second part of the research involves the sub surface stratigraphic correlation of Sulaiman fold belt to Sulaiman Depression. To quantify reservoir different well logs are used which are gamma ray log, neutron log, SP log, resistivity logs, sonic log, and density log. Based on different variation trend of well log curves of different zones of interest have been marked. Furthermore, inverse quality factor responses for gas reserves at different porosities showing that maximum variation is observed at low saturation of gas. Amplitude character is showing class three AVO trend which is showing that good hydrocarbon zone for gas reserves. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive account on the evolution of the Tertiary Himalaya coals of India and their various attributes. The coal bearing sequences in Himalaya have formed in two different geotectonic settings, first under foreland basin (Oligocene coals of Assam, Nagaland and Arunachal Pradesh of northeastern India) and second under Platform basin (Eocene coals of Meghalaya of north-eastern India) conditions. The Jammu coals of northwest India developed in the late Paleocene in the western Himalayan foreland basin. A sea transgression inundated the Jammu area which gave rise to forest swamp and Jammu coals eventually formed under tropical humid climatic conditions in the tropical climatic belt of northern hemisphere. In northeastern India, the Oligocene coals have shown more maturity than the Eocene coals and have relatively high carbon content and they also have developed caking characters in many coalfields. This may be because the Eocene coal developed in the tropical climatic belt when the northern part of the northeast India was still in the southern hemisphere and the Oligocene coal evolved when the northern part of the northeast India was in the northern hemisphere and the collision during the Oligocene in this part improved the maturity of Oligocene coal due to Himalayan orogeny. The Himalayan coals are exceedingly rich in vitrinite with variable quantities of liptinite and inertinite macerals. Dominance of typical Tertiary angiospermic floral assemblage in the Himalayan coals is well indicated by the occurrence of single, double and triple celled telutospores. [ABSTRACT FROM AUTHOR]

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]

The absolute age of the Brusilovka paleo-caldera volcanic rocks has been determined for the first time through the LA-ICP-MS U–Pb zircon isotopic dating. The obtained results (~61–56 Ma) are consistent with the Paleocene magmatic stage of the Sikhote-Alin, and the patterns of their structural localization and spatiotemporal distribution are consistent with left-lateral displacements along the Vostochny and Pribrezhny faults. The distribution characteristics of early Paleogene igneous rocks both in the frontal and rear continental-marginal parts of the southern Sikhote-Alin can serve as a basis for paleogeodynamic reconstructions and subsequent metallogenic analysis. [ABSTRACT FROM AUTHOR]

Numerous bottom current-controlled depositional and erosional features, which together form Contourite Depositional Systems (CDS), have been recognized in deep-water settings over the past decade. Most of these systems are described based on two-dimensional (2D) seismic data, whereas only a few CDS have been characterised from high-resolution 3D data. Here we document a newly identified CDS that formed during the Paleocene within the Morondava Basin, offshore west Madagascar, through analysis of a depth-migrated 3D seismic survey, enhanced by the implementation of seismic attributes. Three seismic units (SU) mark the main evolutionary stages of the CDS: (a) the onset (SU1), (b) drift growth (SU2), and (c) burial (SU3) stages. The growth stage documents lateral upslope migration of a mounded drift and its associated moat. The increasing, long-term influence of bottom currents along the foot of the slope occurred simultaneously with plate tectonic, climatic and oceanographic changes. Evidence amassed from the CDS highly erosive bounding discontinuities, internal discontinuities, and moat architecture all indicate the intermittent behaviour of the currents over shorter time frames during its formation. Drift deposits form under the influence of weaker currents, while discontinuities appear to record the most vigorous currents, producing the large-scale morphology of the system. [ABSTRACT FROM AUTHOR]

Lignite deposits, associated with Akli Formation (Paleocene), from the Sonari mine of Barmer Basin, Rajasthan, were investigated by applying organic petrography, palynofacies, and geochemistry in order to understand the origin, nature, and character of these lignite-bearing deposits and to assess their thermal maturation and hydrocarbon generation potentiality. The studied samples contained an abundance of huminite group of macerals (av. 54.0 vol.%) and relatively higher abundance of C27 and C29n-alkane hydrocarbons. High carbon preference index (CPI: 5.03–9.44) and high terrigenous aquatic ratio (TAR: 5.09–20.01), together with the liptinite macerals (av. 10.3 vol.%), inform the prevailing contribution of higher plants. Besides, the significant amount of detrohuminites (av. 26.8 vol.%) and non-biostructure phytoclasts (av. 42.25%), along with hopanoids, denote a meaningful herbaceous plants input and/or high level of tissue destruction (bacterial activity). The terpenoid composition was mainly constituted by pentacyclic triterpenoids and A-ring-degraded angiosperm-derived compounds and diterpenoids. The inertinite contents (av. 22.3 vol.%) and the pristane/phytane (Pr/Ph) ratio imply the variation in the redox conditions during the accumulation. The petrographic indices revealed that the paleo-flora were accumulated in a limno-telmatic condition, with fluctuating groundwater level. Likewise, the palynofacies data displayed that the peat was deposited in dysoxic-suboxic settings under proximal condition. Subsequently, the incidence of dinoflagellate cysts in the studied samples suggests a marine intrusion. The considerable total of pyrite (up to 16.7 vol.%, comprising framboidal) suggests a coastal swamp condition (marginal marine). The thermal alteration index (TAI: av. 2.15), Tmax (av. 411 °C for lignite and 414 °C for associated shale) and the gross calorific values (av. 4601 cal/g) showed the immaturity of the studied samples. The lignites contained low to moderate ash yields (av. 12.57 wt.%) and moisture (av. 12.79 wt.%) contents, whereas the carbondaf (daf = dry ash-free basis) contents were high (av. 67.22 wt.%) and corroborated well with the inertinite group of macerals. The fuel ratio varied from 0.77 to 1.32. The volatile matter yielddaf (av. 51.09 wt.%), fixed carbondaf (av. 48.91 wt.%), and the oxygendaf (av. 22.16 wt.%) contents were moderately high. The total organic carbon contents (TOC: 1.17–54.84 wt.%, av. 24.78 wt.%) and hydrogen index values (HI: 32–361 mg HC/g rock) exhibit that the studied samples mostly have type III kerogen and show an excellent potentiality to generate gaseous hydrocarbons. [ABSTRACT FROM AUTHOR]

Seismic inversion has been in use for the last two decades to measure inverted impedances using an integrated data set approach. This research focuses on the application of multi-attribute seismic inversion and the geostatistical probabilistic neural network (PNN) approach for determining rock properties and litho-fluid classification in the Mehar-Mazarani Field of the Lower Indus Basin (LIB), Pakistan. The study compares five different inversion techniques, including model-based inversion (MBI), colored inversion (CI), linear sparse spike inversion (LSSI), band-limited inversion (BLI), and maximum likelihood sparse spike inversion (MLSSI). The inverted outputs, such as acoustic P-impedance (Zp), density (ρ), porosity (φ), and shale volume (Vsh), were analyzed in Paleocene and Cretaceous geological complex reservoirs to identify gas-bearing zones. The results indicated the existence of gas between 1630 and 1700 ms (ms) and corresponding depth ranges from approximately 3200 m up to 4200 m with varying thickness. Amongst the inversion techniques, MBI demonstrated greater accuracy, with inverted density volumes showing a strong correlation coefficient of 0.98 and the lowest root mean square error (RMSE) and relative error of 0.10 m/s * g/cc. A geostatistical PNN approach was employed to estimate variations in Vsh and φ within the sand reservoir. MBI again yielded more reliable results, with a strong correlation between the measured and inverted attributes. High φ and low Vsh were observed in predetermined low-impedance zones. Overall, MBI is proven to be the most accurate and reliable technique, providing clear identification of the gas occurrence. This research highlights the effectiveness of seismic inversion, particularly the application of MBI, in determining rock properties and identifying gas-bearing zones within the Mehar-Mazarani gas field. [ABSTRACT FROM AUTHOR]

Palaemonidae is the most speciose shrimp family within the infraorder Caridea, composed predominately of freshwater species and marine symbiotic species. The subject of this study is a clade of mainly free-living marine taxa representing a basally separated lineage from most of the symbiotic marine palaemonid genera. Phylogenetic and biogeographic relationships were explored by analysing sequence data from two mitochondrial and four nuclear markers. Maximum likelihood and Bayesian analyses, based on sequences from 52 species of 11 genera, provided similar tree topologies revealing the genera Palaemonella, Cuapetes and Eupontonia as non-monophyletic groups. Divergence time and S-DIVA analyses reveals that the focal clade originated during the Late Cretaceous in the Paleotethys region respective to the present Indo-West Pacific area, a minor part of which spread out to the eastern Pacific during the Paleocene, followed by further migration into the Atlantic (before the closure of the Panama Isthmus). The ancestral state reconstruction of host associations revealed eight independent symbiotic lineages originating from free-living ancestors, entering primary symbioses. The first associations with Cnidaria are estimated to have evolved in the Eocene. This study points to the need of taxonomic revisions of the non-monophyletic genera concerned. [ABSTRACT FROM AUTHOR]

In the article, our research of the tectono-stratigraphic imprints of the Indian–Asian plates collision in the outcrops of Kurram and North Waziristan agencies in Pakistan with the help of detailed mapping and subsurface modeling, is presented. Three tectonic domains have been identified in the research based on the stratigraphic mismatch including the Nappe Domain, the allochthonous Indian Plate margin (Orakzai Ranges), and the autochthonous Indian Plate margin (Kohat Basin). In our work we focused on establishing the sequence of tectonic events based on the emplacement of the Nappe Domain eastward on top of the other two domains. The rocks from each domain have been measured and logged to determine their stratigraphic differences. Nappe Domain consists of Jurassic and Cretaceous sequence of sedimentary mélange rocks which are intensely folded and faulted and emplaced on the other two domains. These mélange rocks are emplaced on the Eocene shales of Kohat Basin in the southern part of the research area, while the same mélange rocks overlie the Paleocene carbonates in the Orakzai Ranges. This variable emplacement of the mélange sequence signifies that the research area represents the confluence of tectonically distinct blocks which were far apart during the post-Cretaceous and later, from Late Eocene to Miocene, these blocks were juxtaposed under influence of regional faulting. Our research also proves that the emplacement of the mélange rocks from the west started in post-Paleocene in the northern Orakzai Ranges while the southern Kohat Basin was receiving extensive Eocene deposition which was later overlained by the mélange rocks. [ABSTRACT FROM AUTHOR]

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]

The present study aims to investigate the origin, type, thermal maturity and hydrocarbon generation potential of organic matter and paleo-depositional environment of the Early Paleocene (Danian) Hangu Formation outcropped in the Kala-Chitta Range of Northwest Pakistan, Eastern Tethys. Organic-rich shale and coal intervals were utilized for geochemical analyses including TOC (total organic carbon) and Rock–Eval pyrolysis coupled with carbon (δ13Corg) and nitrogen (δ15Norg) stable isotopes. The organic geochemical results showed that the kerogen Type II (oil/gas prone) and Type III (gas prone) dominate the investigated rock units. The TOC (wt%) and S2 yield indicate that the rock unit quantifies sufficient organic matter (OM) to act as potential source rock. However, the thermal maturity Tmax°C marks the over maturation of the OM, which may be possibly linked with the effect attained from nearby tectonically active Himalayan Foreland Fold-and-Thrust Belt system and associated metamorphosed sequences. The organic geochemical analyses deciphered indigenous nature of the OM and resultant hydrocarbons. The δ13Corg and δ15Norg stable isotopic signatures illustrated enrichment of the OM from both marine and terrestrial sources accumulated into the Hangu Formation. The Paleo-depositional model established using organic geochemical and stable isotopic data for the formation supports its deposition in a shallow marine proximal inner shelf environment with prevalence of sub-oxic to anoxic conditions, a scenario that could enhance the OM preservation. Overall, the formation holds promising coal and shale intervals in terms of organic richness, but due to relatively over thermal maturation, it cannot act as an effective source rock for liquid hydrocarbon generation and only minor amount of dry gas can be expected. In implication, the results of this study suggest least prospects of liquid hydrocarbon generation potential within Hangu Formation at studied sections. [ABSTRACT FROM AUTHOR]

Facies associations and environmental evolution of the late Cretaceous—lower Paleocene shallow platform of the Haria Formation (upper Maastrichtian—Danian—Selandian) have been studied from the Gafsa basin, located in southern Tunisia. Four main lithostratigraphic units have been identified. Unit 0, deposited on a restricted platform, is organized into aggradational and shallowing-upward sequences. Unit 1 is composed of shallowing- and deepening-upward sequences that are deposited in externally restricted platform environments. Unit 2 is a peritidal shallowing-upward sequences deposited in shallow restricted environments ranging from the intertidal to supratidal environments. Unit 3, is composed of shallowing-upward sequences corresponding to the "muddy" type in the lower part, deposited in the proximal part of the shallow restricted external platform, and the "grainy" type in the upper part, representing wave-dominated bioclastic shoals and channel deposits. The proximal-distal transition of depositional environments gradually ranges from lagoon to offshore environments. Lateral variation of thickness and facies is generated by the reactivation of NW-SE extensive and/or transtensive faults, acting since the late Cretaceous during the intermediate closing phase of the Neotethys. These tectonic features were also expressed by changes in facies. The Haria Formation's mixed carbonate-marls successions are classified into seven major facies associations, with carbonates considered a new facies represented by channel deposits and lumachellic limestones. This study establishes for the first time a clear and detailed regional stratigraphic correlation and paleogeographic maps based on the new litho- and biostratigraphic data. [ABSTRACT FROM AUTHOR]

To improve the poor Gondwana paleomagnetic database for Devonian times, detailed paleomagnetic analyses were performed on red chert-like rocks and partly silicified paleosols within the Lower Devonian Ikniouen level (fine-grained sandstones including red ironstone) in conformity within the sub-horizontal Tadrart coarse white formations of the Murzuq basin. Silicification, limited to this level that is only a few meters thick, was probably due to tropical warm climatic conditions during and shortly after the rock deposition. In two sections 40 km away each other, paleomagnetic data point out a high-temperature Characteristic Remanent Magnetization (ChRM) with very well-defined mean direction, positive reversal test and relatively high (5) Q and R scores. Rock magnetic data indicate minerals of the hematite family, but the presence of a minor amount of other mineral phases remains possible. At least part of the ChRMs are Chemical Remanent Magnetizations, likely acquired during or shortly after deposition. The corresponding paleomagnetic results (paleomagnetic pole at 28.6° E and 71.1° S, with K = 1004, A95 = 1.5°) could have major geodynamical implications for the Gondwana supercontinent. In fact, ChRM acquired in this level during or shortly after deposition should imply a much-unexpected fast latitudinal continental drift of the Gondwana during the Lower Devonian or a significant and fast true polar wander. Though much more difficult to match with the ChRM and geological characteristics, the only possible alternative interpretation for the Ikniouen data should be a chemical remagnetization acquired during the Late Cretaceous–Early Paleocene times. [ABSTRACT FROM AUTHOR]

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]

The extinct betulaceous genus Palaeocarpinus accommodates fossils with a mixture of characters shared by fruits of the extant genera Carpinus and Corylus. Originally described from the Paleocene of southeastern England, the genus has since been recognized in other parts of Europe, North America and Asia, and into the Eocene. Currently, descriptions exist for ten named Palaeocarpinus species. Here we present a comparative review of all known Palaeocarpinus species to evaluate morphology and diversity. We recognize a broader North American range for the Paleocene species P. joffrensis, and establish three new species, including two from the Paleocene of Wyoming, P. pterabaratra and P. pteravestigia, and one from the Eocene of Oregon, P. parva. We also update nomenclature for the species previously recognized from the Paleocene of France. Lastly, we discuss the morphological diversity and characteristics of bracts within Palaeocarpinus, and compare the involucres and nuts to those of extant Carpinus and Corylus to, and consider the evolutionary implications. [ABSTRACT FROM AUTHOR]

The upper Assam shelf is a self-slope basin in north-east India, filled with nearly 7 km of sedimentary rocks of tertiary period with the granite basement and various oil fields along the border of the Naga thrust. The major producing fields are structural and strati-structural. The study area is placed in between the Mikir hills and Naga thrust. The objective of the study is to identify potential hydrocarbon reservoir zones in the geologically complex south upper of the Assam shelf using estimates of acoustic impedance and porosity derived by 3D post-stack seismic inversion. Well data, such as sonic velocity and density logs, from two wells (namely, KA and TE) are used in the inversion and validation of results. Inversion results are used to build a geological model in the form of acoustic impedance from which we derive 3D porosity cube which are used for hydrocarbon potential in the Paleocene to lower Oligocene sands, and the Precambrian basement. Although the amplitude maps provide an indication of potential reservoirs, the extent of these zones are much better identified in the inverted impedance maps and the corresponding estimated high-porosity zones. The analysis predicted the potential reservoir rocks in the Sylhet, Kopili and Barail formations, in which the Sylhet and Kopili appear to have good potential zones. Near the vicinity of the Naga thrust belt, the proximity of potential reservoir is predicted in the Kopili, Sylhet formation and in the fractured basement, respectively. [ABSTRACT FROM AUTHOR]

The present authors used the scanning electron microscopy and energy dispersive spectroscopy methodology as a standard approach for micropaleontological studies to detect test internal morphological and compositional features of agglutinated foraminifera grains collected from Maastrichtian-Paleogene of the Dakhla Oasis of Egypt. Five main morphogroups dominate Lower Kharga Member, the mixture of infaunal and epifaunal morphogroups indicating mesotrophic conditions during that time. All evolving new species found in the Early Paleocene are small and species richness remains low with small simple test morphologies resembling the under zone CF3 with a new appearance of morphogroup epifaunal flattened planispiral. Zone CF3 of Lower Kharga Member is characterized by the appearances of small-sized Trochammina which are associated with stressful environmental conditions. Zone P1c of the Upper Kharga Member is characterized by high percentages of calcareous agglutinated foraminifera and abundance of granular calcite and hyaline tests, which explained a sufficient quantity of calcium carbonate dissolved in the water and warm water basin. The strong decrease in diversity and heterogeneity of the assemblages, as well as the drastic drop in the number of infaunal elongated morphogroup coincident with the hiatus between CF3 and P1c (Maastrichtian/Danian boundary), indicate a dramatic decrease in the food supply to the sea-bottom floor. [ABSTRACT FROM AUTHOR]

Asiapator onchin gen. et sp. nov. is based on a dentary fragment from the middle Eocene (Irdinmanhan) Khaychin Formation at Khaychin Ula 3 locality, Mongolia. The preserved dentition includes di1 being replaced by i1, dp2 or p2, roots of dp4, and erupting p4. This is the first record of the Apatemyidae in Central Asia. The holotype of A. onchin provides the first direct evidence for dental replacement in the Apatemyidae, showing diphyodont first lower incisor and fourth lower premolar. Asiapator has only one lower incisor as in all apatemyids except Unuchinia from the Paleocene of North America. Asiapator is similar to Unuchinia and differs from more derived apatemyids in having a simple unmodified anterior premolar (dp2 or p2). Asiapator likely evolved from a North American immigrant. [ABSTRACT FROM AUTHOR]

Among the Late Cretaceous fossil sites of Europe, only those from the so-called "Haţeg Island" in Transylvania, western Romania, are remarkable by their abundance in mammal remains. Curiously, all of them belong to a single family of multituberculates, the Kogaionidae, one of the rare families that survived the Cretaceous-Paleogene mass extinction in Europe. Kogaionids are mostly represented by isolated teeth except for three partial large skulls from the Maastrichtian Sânpetru Formation of the Haţeg Basin that have been described from the Sânpetru locality as Kogaionon ungureanui and from the Pui locality as Barbatodon transylvanicus and Litovoi tholocephalos. Here we report for the first time the discovery of a partial skull associated with p4 of a small-sized kogaionid from the Nălaţ-Vad locality in the Sânpetru Formation that we refer to Kogaionon radulescui, sp. nov. An updated phylogenetic analysis, including seven Maastrichtian and Paleocene kogaionids is performed and confirms that Kogaionidae is a monophyletic clade at the base of Cimolodonta. Kogaionon differs from Barbatodon in its narrower snout, proportionally smaller P1, narrower anterior part of P4 with four similar-sized cusps in the middle row, more squared or rounded M1 with an anteroposteriorly longer lingual row, and shorter p4 (at least for K. radulescui). Litovoi tholocephalos is here considered to be a junior synonym of B. transylvanicus. Despite their Maastrichtian age, the very simple and conservative dental morphology of these Romanian kogaionids suggests that they originated from an eobaatarid-like ancestor dispersing from Asia or possibly already existing in Europe between the Barremian and Albian, 40 to 55 Ma earlier. [ABSTRACT FROM AUTHOR]

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]

We describe the tympanic anatomy of the petrosal of Deltatherium fundaminis, an enigmatic Paleocene mammal based on cranial specimens recovered from New Mexico, U.S.A. Although the ear region of Deltatherium has previously been described, there has not been a comprehensive, well-illustrated contribution using current anatomical terminology. The dental and cranial anatomy of Deltatherium is a chimera, with morphological similarities to both 'condylarth' and 'cimolestan' taxa. As such, the phylogenetic relationships of this taxon have remained elusive since its discovery, and it has variably been associated with Arctocyonidae, Pantodonta and Tillodontia. The petrosal of Deltatherium is anteriorly bordered by an open space comprising a contiguous carotid opening and pyriform fenestra. The promontorium features both a small rostral tympanic process and small epitympanic wing but lacks well-marked sulci. A large ventral facing external aperture of the canaliculus cochleae is present and bordered posteriorly by a well-developed caudal tympanic process. The hiatus Fallopii opens on the ventral surface of the petrosal. The tegmen tympani is mediolaterally broad and anteriorly expanded, and its anterior margin is perforated by a foramen for the ramus superior of the stapedial artery. The tympanohyal is small but approximates the caudal tympanic process to nearly enclose the stylomastoid notch. The mastoid is widely exposed on the basicranium and bears an enlarged mastoid process, separate from the paraoccipital process. These new observations provide novel anatomical data corroborating previous hypotheses regarding the plesiomorphic eutherian condition but also reveal subtle differences among Paleocene eutherians that have the potential to help inform the phylogeny of Deltatherium. [ABSTRACT FROM AUTHOR]

In the central-eastern Sirt Basin, enigmatic Intisar domal structures host significant hydrocarbon accumulations. These structures have been commonly interpreted as pinnacle reefs/bioherms occurring in the open-marine basinal environment. Generally, pinnacle reefs/bioherms are mainly characterized by in situ carbonates. The current study challenges the Intisar pinnacle reef/bioherm model by examining one of the domal structures in terms of biostratigraphy, microfacies and depositional environment. These structures were dated using larger benthic foraminifera, which yielded a Middle to Late Paleocene age (Selandian–Early Thanetian). Thirteen microfacies types representing different carbonate ramp environments ranging from outer ramp to inner ramp, were defined. Outer ramp deposits have been observed adjacent to the domal structure, represented mainly by wackestone with small benthic and planktonic foraminifera. The outer ramp deposits are most likely isochronous to the domal structures. The lower part of the domal structures is composed mainly of foraminiferal–algal–echinodermal packstones. The upper part is characterized by foraminiferal–algal–echinodermal packstones with intercalated microbialite–coral boundstones. The euphotic inner ramp deposits are preserved on the crest of the domal structure, consisting of grainstone and packstone rich in Glomalveolina. As a result of this study, the Intisar domal structures are seen as erosional relics of a carbonate ramp and no evidence for pinnacle reef/bioherm model was found. [ABSTRACT FROM AUTHOR]

The Paleocene–Eocene Thermal Maximum (PETM) was a period of geologically-rapid carbon release and global warming ~56 million years ago. Although modelling, outcrop and proxy records suggest volcanic carbon release occurred, it has not yet been possible to identify the PETM trigger, or if multiple reservoirs of carbon were involved. Here we report elevated levels of mercury relative to organic carbon—a proxy for volcanism—directly preceding and within the early PETM from two North Sea sedimentary cores, signifying pulsed volcanism from the North Atlantic Igneous Province likely provided the trigger and subsequently sustained elevated CO2. However, the PETM onset coincides with a mercury low, suggesting at least one other carbon reservoir released significant greenhouse gases in response to initial warming. Our results support the existence of 'tipping points' in the Earth system, which can trigger release of additional carbon reservoirs and drive Earth's climate into a hotter state. The Paleocene–Eocene boundary coincided with runaway global warming possibly analogous to future climate change, but the sources of greenhouse gasses have remained unresolved. Here, the authors reveal volcanism triggered initial warming, and subsequent carbon was released after crossing a tipping point. [ABSTRACT FROM AUTHOR]

Continental crust has long been considered too buoyant to be subducted beneath another continent, although geophysical evidence in collision zones predict continental crust subduction. This is particularly significant where upper continental crust is detached allowing the lower continental crust to subduct, albeit the mechanism of such subduction and recycling of the upper continental crust remain poorly understood. Here, we investigate Paleocene S-type magmatic and volcanic rocks from the Linzizong volcanic succession in the southern Lhasa block of Tibet. These rocks exhibit highly enriched 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb together with depleted 143Nd/144Nd isotope ratios. The geochemical and isotopic features of these rocks are consistent with those of modern upper continental crust. We conclude that these Paleocene S-type volcanic and magmatic rocks originated from the melting of the upper continental crust from microcontinent subduction during the late stage of India–Asia convergence. [ABSTRACT FROM AUTHOR]

Aptian paralic and Paleocene intracratonic mires that bracket the northern reaches of the Western Interior Seaway preserve Milankovitch orbital forcing cycle signals and record the dynamic interplay with craton-linked salt dissolution tectonism in the Alberta Basin foreland and the adjoined intracratonic Williston Basin to the southeast. These mires, now lignite-bearing strata, along the northern Seaway provide a proxy record for Milankovitch orbital signals that would not have been otherwise recorded because of the voluminous clastic sediments accumulated along the western Canadian portion of the Cretaceous Seaway, in contrast to pervasive orbital forcing signals recorded by organic-rich cyclic carbonate deposits accumulated along the central and southern reaches of the Seaway. Prior to opening of the northern segment of the Seaway, the base levels of the paralic mires of the lower McMurray Formation (Aptian) were hydraulically linked to the rising sea-level fluctuations resulting from southward transgression of the Boreal Sea. In contrast, inland fluvial-margin peats of the Paleocene Ravenscrag and Fort Union formations accumulated following the closure of the Cretaceous Seaway. These mires were increasingly sensitive to aquifer-eustatic controls on the water table–mire relationship. Orbital forcing signals were preserved in the central Williston Basin mires in contrast to their masking by salt dissolution collapse-subsidence structures that exerted dominant control on peat mire configurations across the northern Williston Basin. Paralic mires accumulated at the top of the lower McMurray Formation record short-term orbital forcing, possibly representing an obliquity cycle recorded by lithotype sequencing in petrographic profiles. Mires accumulated along the coastal areas during the transition from a lowstand system tract to an early transgressive system tract. The linkage of sea level with coastal water table fluctuations permitted pervasive accumulations of paralic mires at the top of the lower McMurray Formation. Internal mire cycles resulted in coal lithotype profiles responsive to Milankovitch fifth-order and higher sub-cycles. In contrast, concurrent cataclysmic sinkhole collapses and differential fault block displacements were responsive to underlying salt removal patterns. The sea level/water table linkage was punctuated by the salt tectonism and orbital forcing signals were masked, resulting in sinkholes infilled with different coal lithotype sequences. Following the closure of the Western Interior Seaway, inland Paleocene fluvial-margin mires across the northern intracratonic Williston Basin were responsive to larger scale salt removal events in the subsurface. The collapse-subsidence structures were propagated several km up-section, diffused but sufficient to control mire configurations and mask orbital forcing signals. Southward into the central and southwestern Williston Basin, these strong salt dissolution tectonism patterns were out-of-phase with the repetitive mire accumulations, permitting the recognition of the markedly weaker signals of the 100 kyr orbital eccentricity cycle. [ABSTRACT FROM AUTHOR]

The organic-rich shale intervals of Patala Formation of Paleocene age may be considered as potential shale gas play in the Upper Indus Basin of Pakistan. Until now, seismic and elastic properties of the Patala shales are not investigated in detail necessary to declare it as shale gas play and to differentiate shale gas pay zone from the non-pay zone. Data of eight wells in which Patala shales were encountered at various depth levels from 2000 to 4300 m were deeply investigated for shale gas characterization. This shale fulfills the basic criteria of organic-rich shale with TOC ~ 0.5–5.8%, vitrinite reflectance (level of maturity) is 0.6–1.7%, average thickness 48 m. The brittleness index (BI) of this organic-rich shale was computed by using effective mechanical properties and mineralogy to define brittle zones in the shale intervals preferable for generating the fracture network. BI data points demonstrate that a large number of values fall in the brittle zone, whereas fewer values fall in the ductile zone. However, a certain number of values fall in the brittle–ductile transition zone. The quantitative comparison between different elastic and seismic properties derived from the wireline logs guide for the delineation of the pay zone from the non-pay zone in the organic-rich shale intervals. [ABSTRACT FROM AUTHOR]

In this study the hydrocarbon generation potential of the coal and coaly shale samples collected from coal mines in Attock-Cherat Range of Pakistan is optically and analytically evaluated. These samples, representing the Paleocene Hangu Formation, are analyzed across a range of thermal maturity stages to understand their hydrocarbon generation potential. The visual examination of maceral type and values of vitrinite reflectance have been considered while interpreting the geochemical results for the coal and associated sediments from the Paleocene Hangu Formation. The maceral group is dominated by vitrinite, mainly collodetrinite, followed by inertinite and liptinite, and suggests Type III kerogen for the samples. The geochemical parameters suggest that the samples are post mature, however, the vitrinite reflectance measurements show late mature conditions for a gas-prone generation. The overall petrographical and geochemical data suggest that the coal and coaly shale appear to occupy the gas window and fall in the dry gas zone. Based on the maceral types and Rock–Eval data, an anoxic to terrestrial environment is inferred for the deposition of the coal and associated sediments. The vitrinite reflectance, Rock–Eval pyrolysis, and the type and frequency of macerals show that the coal is of good quality, i.e., medium to high volatile bituminous and hard brown coal, mature, and is lying in the gas window. Oxygen index is continuously low throughout the analyzed interval, which further supports that the coal is of good quality. [ABSTRACT FROM AUTHOR]

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X23070334 [ABSTRACT FROM AUTHOR]

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]

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]