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Huaxiazhoulong shouwen gen. et sp. nov. is a new ankylosaurid recovered from the Upper Cretaceous Tangbian Formation of Jiangxi Province, southern China. Huaxiazhoulong shouwen can be diagnosed on the basis of three autapomorphies (the middle shaft and distal end of the ischium are expanded; the ratio of width of distal end to minimum shaft width is greater than 3 in humerus, the maximum length of femur to humerus length ratio is about 1.45) and a unique combination of characters (the centra of anterior caudal vertebrae in anterior view is heart-shaped; the dorsal surface of scapula is straight; the scapulocoracoid has a large medial brace; the humeral head and deltopectoral crest are separated by a distinct notch anteriorly). The phylogenetic analysis shows that Huaxiazhoulong shouwen is an early member of Ankylosauridae. [ABSTRACT FROM AUTHOR]

A new specimen, MAU-Pv-PH-453, comprising an isolated femur from the Plottier Formation (Coniacian-Santonian), northern Patagonia, is described here. Its characteristics, i.e., an anteriorly curved diaphysis; fused lesser and greater trochanters forming a trochanteric crest; a prominent medially directed head; and the absence of a fourth trochanter, allow us to identify it as belonging to a maniraptoran theropod. Among Patagonian maniraptorans, MAU-Pv-PH-453 shares similarities with alvarezsaurians, such as the absence of a posterior trochanter, a trochanteric shelf, and the fourth trochanter. However, in Patagonian alvarezsaurs, the lesser and greater trochanters are generally separated by a cleft. Notably, MAU-Pv-PH-453 exhibits some features seen in femora of parvicursorine alvarezsaurids, including a proximally projected trochanteric crest and an L-shaped profile in proximal view. However, MAU-Pv-PH-453 presents differences with parvicursorines, such as a knob partially separating the lesser and greater trochanters. Phylogenetically, MAU-Pv-PH-453 may have parvicursorine affinities, although its fragmentary nature might generate a bias in its phylogenetic position. Due to the lack of more diagnostic characters, MAU-Pv-PH-453 is assigned to Alvarezsauria indet. This material represents the second theropod record from the Plottier Formation and it could fill a temporal gap (between Coniacian and Santonian) in the record of Upper Cretaceous Patagonian alvarezsaurians. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous Ganzhou Basin of Jiangxi Province, South China is among one of the richest egg fossil sites in the world and yields abundant exquisite egg clutches and embryonic eggs, especially in oviraptorosaurs. Hadrosaurian, troodontid, and potential dromaeosaurid egg fossils were also reported, though they were rare. All these reported eggs vary in morphology but have relatively large sizes. Here, we report a partial egg clutch with six complete small eggs from the Upper Cretaceous Tangbian Formation of Ganzhou City, Southeast China. The microstructure of the eggshell indicates that it can be assigned to Ovaloolithidae. Hence, we established a new ootaxon, Minioolithus ganzhouensis oogen. et oosp. nov. based on a unique combination of characters, including a small egg size, irregular egg arrangement, worm-like and nodular ornamentation, and a gradual boundary between two structural layers. The egg morphology and eggshell microstructure support it to be the smallest known non-avian theropod egg up to date. This discovery increases the diversity of dinosaur eggs in the Late Cretaceous and is significant for our understanding of the evolution of theropods in the Late Cretaceous. [ABSTRACT FROM AUTHOR]

Nanhsiungchelys (Testudines: Nanhsiungchelyidae) has been established in the 1960s, but its plastral morphology is not well understood. Here, we report an anterior lobe of the plastron of Nanhsiungchelys from the Upper Cretaceous of Ganzhou Basin, China. The plastron of the new specimen bears a V-shaped notch anteriorly which is absent or unknown in other Nanhsiungchelyidae. Besides, we also further describe the plastron of the holotype of Nanhsiungchelys yangi. These two specimens reveal that the plastron of Nanhsiungchelys spp. is partly hollow, and may have additional ossifications of the epiplastra. All of these suggest an unusual plastral morphology and evolution of Nanhsiungchelys. [ABSTRACT FROM AUTHOR]

The Mamonia Mélange in the Ayia Varvara area (southwestern Cyprus) is characterized by a matrix supported mélange which is composed of tectonized siltstones and mudstones with numerous blocks that were derived from the Mamonia Allochthonous Complex (Petra tou Romiou Formation reefal limestones, Phasoula Formation volcanics, Kholetria Member pelagic limestones, Akamas Member sandstone, Parekklisha Member sandstone, Ayia Varvara Formation metamorphics and Episkopi Formation radiolarian cherts). Subordinate blocks were derived from the Troodos Ophiolite Complex: serpentinites, gabbro, pillow lavas and cherty umbers (Perapedhi Formation). Radiolarian assemblages from chert blocks display a broad spectrum in age, ranging from the Late Triassic (latest Carnian–early Norian) to the youngest Cenomanian. The composition of the mélange in the Ayia Varvara area differs from the one described in the Petra tou Romiou area (SW Cyprus), as various lithologies were recorded (like Akamas Member sandstone and Parekklisha Member sandstone) which were not detected previously. The Mamonia Mélange was formed during the Late Cretaceous, most probably after the end of deposition of the Perapedhi Formation (late Santonian–early Campanian). [ABSTRACT FROM AUTHOR]

The stratigraphical features and palaeoenvironmental conditions of the upper Cenomanian–lower Coniacian carbonates from the northern part of the Aures Range are described for the first time. Four formations have been recognised, namely the Arris, Adahri, Yabous, and Bou Ouali, respectively. Planktonic foraminifera enable us to assign the upper part of the Arris Formation and the lower part of the Adahri Formation to the Middle–Upper Cenomanian (Rotalipora sp. cf. R. cushmani Total Range Zone), the upper part of the Adahri Formation to the Cenomanian–Turonian Transition to the lower Turonian (Whiteinella archaeocretacea Partial Range Zone and Helvetoglobotruncana helvetica Total-Range Zone, respectively), the lower member of the Yabous Formation to the middle Turonian (Marginotruncana sigali Partial Range Zone), and the upper member of the Yabous Formation to the upper Turonian (Marginotruncana schneegansi Partial Range Zone). The Turonian–Coniancian boundary was dated approximately. This biozonation enables a correlation with several upper Cenomanian–lower Coniacian sections outside Algeria, mainly within the Tethyan and Boreal domains. Based on the field data, and microfacies studies, the strata of these formations are arranged into eleven microfacies types (MT 1 to MT 11) that are described in terms of depositional environments, and grouped into three main facies associations (FA 1, FA 2, and FA 3): (i) a deep shelf-basin facies zone; (ii) marginal sand shoals, an open-marine/restricted platform facies zone; and (iii) an outer platform and toe-of-slope/distal slope facies zone. Analysis of the sequence stratigraphy has allowed the recognition of three third-order depositional sequences grouped into two megasequences and correlated to a regional scale. [ABSTRACT FROM AUTHOR]

The paper presents detailed biostratigraphical division and lithological characteristics of the Turonian-Lower Santonian interval within the compiled Chukhonastovka section. The presence of the Lower Turonian deposits has been ascertained alongside with the unusual structure of the rock interval synchronous to the Lower Santonian “sponge” horizon.

A representative complex of the Turonian-Santonian carbonate-producing invertebrates has been revealed. It comprised benthic foraminifers, diverse echinoderms, brachiopods, calcareous and siliceous sponges.

Abstract Tyrannosaurids were the most derived group of Tyrannosauroidea and are characterized by having two body plans: gracile, long-snouted and robust, deep-snouted skulls. Both groups lived sympatrically in central Asia. Here, we report a new deep-snouted tyrannosaurid, Asiatyrannus xui gen. et sp. nov., from the Upper Cretaceous of Ganzhou City, southeastern China, which has produced the large-bodied and long-snouted Qianzhousaurus. Based on histological analysis, the holotype of Asiatyrannus xui is not a somatically mature adult, but it already passed through the most rapid growth stages. Asiatyrannus is a small to medium-sized tyrannosaurine, with a skull length of 47.5 cm and an estimated total body length of 3.5–4 m; or around half the size of Qianzhousaurus and other large-bodied tyrannosaurines in similar growth stages. Asiatyrannus and Qianzhousaurus are sympatric tyrannosaurid genera in the Maastrichtian of southeastern China. Asiatyrannus differs from Qianzhousaurus in that it has a proportionally deeper snout, longer premaxilla, deeper maxilla, and deeper dentary, and the cornual process of the lacrimal is inflated without developing a discrete horn. The different skull proportions and body sizes suggest that Asiatyrannus and Qianzhousaurus likely had different feeding strategies and occupied different ecological niches.

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

The study of new finds of mosasaurids from the Izhberda locality (Southern Urals, Orenburg Region) has made it possible to record for the first time the presence of mosasaurs from the subfamilies Mosasaurinae, Tylosaurinae, and Plioplatecarpinae from the Upper Cretaceous of the Orenburg Region, including representatives of the genera Mosasaurus, Prognathodon, and Clidastes, which are known from the Upper Cretaceous of North America and Western Europe. Of interest is the discovery of the tylosaurine Taniwhasaurus, previously known from New Zealand, Antarctica, South Africa, and Japan. Therefore, the Campanian mosasaurid fauna of the Southern Urals is intermediate and includes North American–European and Asia–Pacific taxa. However, all the finds of mosasaurs from the Izhberda locality can only be identified in open nomenclature, which makes detailed comparisons of the faunas difficult. Revision of the type series of mosasaur Liodon rhipaeus Bogolyubov, 1910 from the Southern Urals has allowed us to conclude that, in addition to the three mosasaurian vertebrae, it includes the ischium and posterior fragment of the mandible of a plesiosaur. Liodon rhipaeus is clearly a nomen dubium and the vertebrae of its type series cannot be identified more precisely than Tylosaurinae indet. [ABSTRACT FROM AUTHOR]

Numerous representatives of the genus Foremanina Empson-Morin, 1981, emend. nov. were studied from the Upper Cretaceous (Maastrichtian) of the Lefkara Formation (Cyprus). The diagnosis of the genus Foremanina is emended. The new species F. macropora sp. nov., F. coronata sp. nov. and F. ornata sp. nov. are described. F. macropora sp. nov. is recorded for the first time in the Campanian of Sakhalin. The paleogeographic distribution of genus Foremanina is expanded to include the Tethyan Realm and Pacific Realm including the Mid-Pacific Mountains and Hokkaido–Sakhalin paleobasin. The latest representatives of Foremanina were found for the first time in the upper Maastrichtian of Cyprus. The stratigraphic range of the genus Foremanina is expanded. [ABSTRACT FROM AUTHOR]

Tyrannosaurids were the most derived group of Tyrannosauroidea and are characterized by having two body plans: gracile, long-snouted and robust, deep-snouted skulls. Both groups lived sympatrically in central Asia. Here, we report a new deep-snouted tyrannosaurid, Asiatyrannus xui gen. et sp. nov., from the Upper Cretaceous of Ganzhou City, southeastern China, which has produced the large-bodied and long-snouted Qianzhousaurus. Based on histological analysis, the holotype of Asiatyrannus xui is not a somatically mature adult, but it already passed through the most rapid growth stages. Asiatyrannus is a small to medium-sized tyrannosaurine, with a skull length of 47.5 cm and an estimated total body length of 3.5–4 m; or around half the size of Qianzhousaurus and other large-bodied tyrannosaurines in similar growth stages. Asiatyrannus and Qianzhousaurus are sympatric tyrannosaurid genera in the Maastrichtian of southeastern China. Asiatyrannus differs from Qianzhousaurus in that it has a proportionally deeper snout, longer premaxilla, deeper maxilla, and deeper dentary, and the cornual process of the lacrimal is inflated without developing a discrete horn. The different skull proportions and body sizes suggest that Asiatyrannus and Qianzhousaurus likely had different feeding strategies and occupied different ecological niches. [ABSTRACT FROM AUTHOR]

Atlantoceratodus iheringi (Ameghino, 1898) from Argentine territory is restudied based on its known tooth plates and newly discovered material, which includes previously unknown skull roof bones and vomerine tooth plates. The latter represent the first records of such elements from the Mesozoic era in South America. The comparative morphological analysis reveals its distinctiveness from other dipnoans, and offers valuable data for future systematic and phylogenetic research. The pterygopalatine tooth plates display narrow-based first denticulations and lack anterior wear facets, with the inner angle positioned at the level of the second denticulation. Similarly, the prearticular tooth plates feature straight mediolingual edges, and a wide-based first denticulation without sinuosities at the tip. Histological sections are performed and analyzed in detail for the first time. A. iheringi presents in this aspect distinctive features such as: large-lumen denteons tending to cluster together, circumdenteonal dentine arranged in a double band (an inner birefringent and an outer monorefringent), and a disordered interdenteonal dentine, with birefringence surrounding denteons and areas with monorefringence. A. iheringi exhibits histological structure closer to Mesozoic and Cenozoic dipnoans than Paleozoic, especially resembling the disposition observed in the Upper Cretaceous Patagonian species Metaceratodus baibianorum. The wide distribution of features designated as diagnostic for Atlantoceratodus is discussed. [ABSTRACT FROM AUTHOR]

A new genus and species, Cretopleciofungivora simpsoni gen. et sp. nov., from the extinct family Pleciofungivoridae (Diptera: Bibionomorpha), is discovered in mid‐Cretaceous Kachin amber. Previously, this family was known only from imprints in sedimentary rocks of the Jurassic and the Lower Cretaceous. Discovery of a representative of Pleciofungivoridae in Kachin amber confirms the presence of the family in the Upper Cretaceous. The new species has a unique structure of fore tarsus, with lobed and extended tarsal segments II to IV, a feature hitherto known only in a few species of extant Sciaroidea. Although not particularly rare, the new species is currently known only from female specimens. Possible reasons for this phenomenon, very unusual in Sciaroidea, are briefly discussed, including parthenogenesis as a potentially plausible hypothesis. [ABSTRACT FROM AUTHOR]

A Cenomanian ammonite, Calycoceras (Calycoceras) naviculare (Mantell, 1822) (Acanthoceratidae, Ammonoidea) has been found in the well-known section of the Selbukhra Mountain in the vicinity of the village of Nauchnyi in southwestern Crimea. This is the first find of the ammonite in the upper Cenomanian deposits in the Crimea and in Russia. [ABSTRACT FROM AUTHOR]

Representatives of the genus Sororistirps, distinguished among the Ventriculites, have been detected in the Santonian – Maastrichtian rocks from the southeast of the Russian Plate. The structures of the skeletons and of the irrigation systems have been considered, the Sororistirps morphogenesis has been traced; the forms characteristic of the Santonian, Campanian and Maastrichtian spongiocomplexes have been determined.

Ammonites of the subfamily Collignoniceratinae have been found in the Turonian Stage of Western Siberia. These findings have made it possible to substantiate the Collignoniceras woollgari zone in the Middle Turonian of this region, to recognize the ammonite dispersal features in the Arctic region, and to clarify the paleogeography of the Turonian age. Based on the occurrence frequency of Collignoniceras woollgari regulare in the boreholes in the north of Western Siberia, their penetration into the West Siberian basin through the Arctic region from the Western Interior Sea of North America is most likely. Collignoniceratinae has been identified for the first time in the Upper Turonian of the Yangoda River (west of the Yenisei–Khatanga regional trough). [ABSTRACT FROM AUTHOR]

The Western Desert of Egypt is recognized for its significant potential in oil and gas reserves, making it a prominent hydrocarbon-producing area with conventional reservoirs. Recent findings from various wells suggest that unconventional reservoirs in the Western Desert may hold considerable promise. The primary objective of this study was to explore this potential. Accordingly, a comprehensive and multidisciplinary approach has been employed to assess the Abu Roash/F (AR/F) reservoir. The methodology involved meticulously examining formation characteristics and integrating borehole images with existing core data and thin sections. This integration aimed to analyse and interpret the lithofacies of the reservoir, with a specific focus on identifying fractures and decoding potential diagenesis effects. As a result, we successfully identified wells exhibiting optimal reservoir quality, unveiling the presence of fractured dolomite or vuggy dolomite in wells containing promising oil and gas pay intervals. Notably, some wells displayed low porosity (3%), yet seismic attribute maps in their vicinity indicated a high density of fractures. This underscores the importance of combining borehole images with seismic attributes to evaluate carbonate formations effectively. The fractures, predominantly oriented NW–SE, were found to be associated with deformation zones. Our findings emphasize the critical role of this integrated approach in unlocking the full potential of hydrocarbon reservoirs in the Western Desert. [ABSTRACT FROM AUTHOR]

Stratigraphy of Campanian deposits in the stratotype of the Kudrinskaya Formation in the Southwestern Crimea is revised. For the first time, integrated sedimentological, biostratigraphic (ichnofossils, cephalopods, inoceramids, foraminifers, dinocysts, nannoplankton, gilianelles), isotope-geochemical, paleo- and petromagnetic characteristics of the section were obtained. The boundary of the lower and upper Campanian is substantiated and confirmed by U–Pb dating of zircons from the well-known bentonite (kil) clay bed in the interval of 77–80 Ma. It is proposed to accept the Campanian Substage boundary of the General Stratigraphic Chart (for bipartite stage subdivision) at the top of the Chron C33r, located near the δ13C isotopic excursion "MCaE" – Mid-Campanian Event, near the first occurrence of the benthic foraminifer Brotzenella monterelensis and a number of other traditional biomarkers. [ABSTRACT FROM AUTHOR]

A Turonian ammonite, Kamerunoceras sp. ex gr. turoniense (d'Orb.) has been found for the first time in the southwestern Crimea, in the section of the Aksu-Dere ravine, northward of the village of Kudrino (Kacha River basin). This is the first discovery of representatives of this genus in Russia. [ABSTRACT FROM AUTHOR]

Knowledge of the Campanian-Maastrichtian titanosaurian sauropods from southern South America has increased markedly in recent years. Several taxa have been reported from northern Patagonia, as well as few taxa from southern Patagonia that were described in the last years. However, titanosaurs from the end-Cretaceous of Central Patagonia are poorly known. Here we report the associated remains of a new species of a titanosaurian sauropod from the La Colonia Formation found in northern Chubut Province. Titanomachya gimenezi gen. et sp. nov. is represented by a caudal vertebra and appendicular elements. Titanomachya, is interpreted as a member of Lithostrotia, sharing derived features with saltasaurids and bearing unique characteristics in the astragalus. The astragalus morphology of Titanomachya display an intermediate form between Colossosauria and Saltasauroidea, allowing articulation between zeugopodium and autopodium with contributions from both the tibia and fibula. The type specimen is a small-sized adult, estimated at 5.8–9.8 tons. Comparative analyses reveal distinct sauropod faunas in different Patagonian regions and Brazilian formations during the Campanian – Maastrichtian. In northern Patagonia, aeolosaurines and saltasaurines predominate, while in southern Patagonia predominate colossosaurians and other large titanosaurs. The less well-known sauropod fauna from central Patagonia includes aeolosaurines, eutitanosaurs, and the addition of small-bodied saltasauroids such as Titanomachya. [ABSTRACT FROM AUTHOR]

The article describes four species of agglutinated foraminifers belonging to three genera (Verneuilina, Orbignyna, and Spiroplectammina) three superfamilies (Verneuilinoidea, Ataxophragmoidea, and Spiroplectamminoidea) and two orders (Ataxophragmiida and Ammodiscida, suborder Textulariina). Benthic species of foraminifers play an important role in the stratigraphic subdivision of the Upper Cretaceous deposits of the Northern outskirts of Donbas and correlation with adjacent territories, as they make up the most part of the assemblage in the samples. For this region, the foraminifera species Verneuilina muensteri Reuss, 1854, Orbignyna variabilis (d’Orbigny, 1840), Orbignyna pinguis Woloschyna, 1961, and Spiroplectammina baudouiniana (d’Orbigny, 1840) were monographically described for the first time. For each species of foraminifers, a detailed description of shell morphology is given. According to the biozonal scale of the Upper Cretaceous deposits of the East European Platform, Verneuilina muensteri is one of the characteristic species of the Upper Turonian Gavelinella moniliformis s. l. foraminifer zone, the species Orbignyna variabilis is typical for the Upper Santonian Gavelinella stelligera zone, and the species Orbignyna pinguis is characteristic of the Upper Campanian Globorotalites emdyensis zone. The species Spiroplectammina baudouiniana is also described. The stratigraphic and lateral distribution of each species of agglutinated foraminifers is indicated, and the deposits and sections of the Northern outskirts of Donbas in which they occurred are indicated. A schematic map of the region is presented, showing the studied sections in which shells of these species were found. These species are found in the rocks of the Shyroka, Yelanchyk, Kryva Luka, Sydorove, Konoplyanivka, and Kamianyi Brid formations of the Northern outskirts of Donbas, which are represented by chalk, marls, and calcareous sandstones. The work presents images of foraminifer species taken with a scanning electron microscope JSM-6490LV (JEOL Ltd., Japan). The article deepens our knowledge of some agglutinated foraminifers from the Upper Cretaceous deposits of the Northern outskirts of Donbas, which are characteristic species of the zone, contributing to further solving the issues of stratigraphy and correlation of these deposits.

Abstract—In 394 samples characterizing 266 stratigraphic levels in four Turonian–Santonian sections of the Southwestern Crimea, characteristic remanent magnetization components (ChRM) acquired at the stage of diagenesis are identified. The obtained data fix the record of the paleosecular geomagnetic variation of high amplitude (root mean square deviation S = 25.9° with a fixed cut-off angle of 45°, which is about twice as high as the model S for this latitude) in the sediments formed during ~5–6 Myr and is interpreted as anomalous behavior of the geomagnetic field in the Turonian, Coniacian, and Santonian. [ABSTRACT FROM AUTHOR]

Numerous representatives of the genus Pseudodictyomitra Pessagno, 1977 were studied from the Upper Cretaceous of the Perapedhi Formation (Cyprus). The new species P. venusta sp. nov. is described. The description and stratigraphic range of P. crassa Bragina, 2013 are emended. [ABSTRACT FROM AUTHOR]

The stratigraphy of the Kerch–Taman region has been refined based on foraminiferal assemblages from the clay pulp of the Semigorsky, Andrusov, and Borukh-Oba mud volcanoes. Comparison with the fauna from the reference section of the Paleogene along the Belaya River (Republic of Adygea) enabled us to reveal deposits of the Middle Eocene (Cherkessk and Kuma formations of the Lutetian and Bartonian stages); Lower Oligocene (Pshekha Formation, Rupelian Stage), confirmed by finds of remains of pteropods; and Middle Miocene (Konkian and Sarmatian stages of the Eastern Paratethys regional scale of the Miocene). Cretaceous deposits (Semigorsky Volcano) are attributed to the Late Campanian–Maastrichtian. [ABSTRACT FROM AUTHOR]

Abiostratigraphic assessment of the benthic foraminiferal record at International Ocean Discovery Program (IODP) Site U1513 in the Mentelle Basin (southeast Indian Ocean, offshore western Australia), yielding a Turonian through Santonian deep-water benthic foraminiferal assemblage is presented. Predominantly calcareous deep-water benthic foraminifera are recovered, whereas agglutinated benthic taxa show a rare occurrence. Epifaunal benthic foraminifera make up ~50% of the total assemblage during the Turonian to Santonian. The most frequently recorded taxa are gavelinellids and gyroidinoids. Adistal, bathyal depositional environment is inferred. Two distinct benthic foraminiferal associations, the Gavelinella berthelini association and the Notoplanulina rakauroana association, were identified in the 160 m-thick succession, and together they yield over 190 taxa. At Site U1513 the occurrence of important benthic foraminiferal markers such as Gavelinella berthelini and the Notoplanulina lineage allows a good correlation with other localities in the southern hemisphere and tentatively with the Pacific Realm. Gavelinella bethelini, which is present from the base of the Turonian succession, shows its last occurrence shortly after the Turonian/Coniacian boundary. Notoplanulina rakauroana is recorded to range from the lower Coniacian through the uppermost Santonian. Throughout the Southern Hemisphere, a similar sequence of benthic foraminiferal bioevents in the Upper Cretaceous can be identified at the Walvis Ridge, in South Africa, Argentina, Southern India, the Kerguelen Plateau, the Great Australian Bight, and in New Zealand. This study aims at contributing to the development of an Upper Cretaceous calcareous benthic foraminiferal zonation applicable to the Southern Hemisphere. [ABSTRACT FROM AUTHOR]

Grain size analysis, heavy mineral analysis, and petrographic studies of sandstones of the Ajali Formation near Imoru (south of the Ifon), the western flank of the Anambra Basin, were conducted to determine the provenance and depositional environment. The textural attributes of the Ajali Sandstone were inferred from the statistical variables namely graphic mean, graphic kurtosis, inclusive graphic standard deviation (sorting), inclusive graphic skewness with values of 0.37 - 1.17 (average 0.55Ø), -9.84 - 3.07 (average 0.09Ø), 0.05 - 1.02 (average 0.75Ø), and -0.03 - 1.00 (average 0.35Ø) respectively. Bivariate plots, such as simple skewness measure versus standard deviation (sorting) and mean versus sorting, suggest that the Ajali Sandstone is mainly a fluvial environment. The petrographic result indicates that quartz is the dominant detrital component with iron oxide, and hematite and goethite are the major cement in the analyzed sandstone sample. The zircon--tourmaline--rutile (ZTR) indices range from 67.65% to 73.17%, indicating that the sandstones are sub-mature to mature. Provenance indicators support igneous rocks of acidic compositions (e.g., granite) and high-grade metamorphic rocks (e.g., granite gneiss) of the Basement Complex of Southwestern Nigeria. [ABSTRACT FROM AUTHOR]

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The purpose of the research was to examine the Upper Cretaceous sedimentary sequence in northwest Iran, in particular, the Shahin Dezh geographical region in two stratigraphic sections, Godollu and Tark-e Viran, which revealed a thickness of 156 meters for the former and 114.5 meters for the latter. Field studies revealed that the lithological features and macroscopic characteristics of the rock sequence of the Godollu section can be divided into 12 lithological units. Sandstone petrofacies exhibit mature textural features and are classified as litharenites based on the composition of the main grains, reflecting sedimentation on a shallow marine shelf and slope. These studies also indicated that the carbonate sequence of the Tark-e Viran section can be divided into 11 separate lithological classes, and based on the laboratory studies, the microscopic samples consisted of three groups, namely, pelagic microfacies with mudstone bioclastic facies, Globotruncana wackestone, and Oligostegina packstone. These classifications are comparable to Flugel's SMF 3 and were deposited in the facies zone of FZ_1 and FZ_3, evoking the depositional environment of relatively deep seas. Geochemical studies on the elements of strontium, sodium, manganese, and iron revealed that the amount of strontium and sodium is very low while the amount of manganese and iron is higher than the carbonate equivalents of the present era. Due to the increased effect of late meteoric diagenesis, the amount of iron increases with the increase of manganese, and the changes of Sr/Ca compared to manganese represent an open diagenetic system reflecting that of the late meteoric diagenesis. As such, the studied limestones can be best classified as semi-polar types with the primary composition of calcite mineralogy. [ABSTRACT FROM AUTHOR]

Crocodyliformes have a well-known worldwilde fossil record, revealing a high diversity of morphological traits, habits and being abundant in their paleofaunas. Such abundance in the fossil record is remarkable in the tetrapod fossil record in the continental sequences of Bauru Group (Brazil), in the Cretaceous of the South America. Here we describe and analyse three specimens from Bauru Group, assigned to a poorly understood crocodyliform clade: Itasuchidae. Their morphological similarity assigned them as Pepesuchus (from Turonian / Coniacian of Araçatuba Formation), Itasuchus cf. jesuinoi, and cf. Roxochampsa paulistanus (both last from Campanian to Early Maastrichtian of Presidente Prudente Formation). The phylogenetic and morphometric results corroborated the monophyly of the Itasuchidae with some variation in its content regard to prior and similar analyses (i.e. inclusion of Stolokrosuchus, Barreirosuchus and Antaeusuchus; exclusion of Caririsuchus), also pointing out to the South American itasuchid species as occupying a crocodyliform morphospace, which can imply distinct niche occupations. The Bauru Group undergoes a diversity peak of archosaurs in Upper Cretaceous, with a remarkable Crocodyliformes radiation, such as the Itasuchidae group, which probably have their most early-diverging lineages rising from Lower Cretaceous of Africa. [ABSTRACT FROM AUTHOR]

The lithological, paleontological and biostratigraphic characteristics of the Turonian–Coniacian deposits of the Lower Bannovka section, the stratotype of the Bannovka Formation (Volga region, Turonian) are presented. Magnetostratigraphic characteristics of thе sediments have been supplemented and elaborated. Petromagnetic data contribute to more refined stratigraphy of the section and facilitate the revealing of depositional rhythmicity. Paleomagnetic data combined with benthic foraminifera data enable the most detailed correlation of the Turonian–Coniacian deposits in the Volga region. Results of a comprehensive study of this stratigraphic unit within the southeastern arch of the Ulyanovsk-Saratov trough revealed patterns in the distribution of the Gubkino Horizon, determined by regional tectonics and processes preceding deposition in the Coniacian and Santonian. [ABSTRACT FROM AUTHOR]

New data on the taxonomic composition and stratigraphic distribution of benthic and planktonic foraminifera in the Campanian–Maastrichtian interval of the Beshkosh section (Southwestern Crimea) are presented. Samples were collected using the "sample-to-sample" method for different types of analysis. Zones and Beds were established on the basis the foraminiferal succession. The Angulogavelinella gracilis LC 18 Zone, Bolivinoides draco LC 21 Zone, Brotzenella praeacuta LC 22 Zone and Beds with Gavelinella sahlstroemi were recognized using benthic foraminifera and Beds with Laeviheterohelix glabrans, Guembelitria cretacea Zone were recognized using planktonic foraminifera. All recognized biostrata are correlated with magnetostratigraphic, palynomorph and macrofauna events. Beds and zones recognized based on benthic foraminifera are correlated with Campanian–Maastrichtian bioevents in sections of the European paleobiogeographic region. Planktonic foraminiferal data are correlated with the International Stratigraphic Scale (Tethys Region) and the regional stratigraphic scheme of Poland. For the first time, 15 species of nine planktonic foraminifera genera and 38 species (25 of which were found for the first time) of 25 benthic foraminifera genera have been identified in the Beshkosh section. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous strata of the Zagros area is named Gurpi Formation. The selected stratigraphic section is attributed to a part of Folded–Thrust belt Zone of the Zagros, located 90 km southeast of Shiraz (SW of Iran) and is affected by the Sarvestan basement Fault within the Interior Fars region. The Gurpi Formation is extended approximately 28 m thick and is mainly formed of marly limestone, shale and argillaceous limestone, The biostratigraphy of the Gurpi Formation was investigated by collecting 121 samples from a selected stratigraphic section. Microscopic investigation represents the presence of 12 genera and 27 species of planktonic foraminifera. The stratigraphic distribution of investigated planktonic foraminifera represents eight biozones. The identified biozones in the Kharameh area from base to the top of Gurpi Formation consist of Helvetoglobotruncana helvetica Total Range Zone, Marginotruncana sigali Partial Range Zone, Dicarinella primitiva Interval Zone, Dicarinella concavata Interval Zone, Dicarinella asymetrica Total Range Zone, Globotruncanita elevata Partial Range Zone, Globotruncana ventricosa Interval Zone, Globotruncana aegyptiaca Total Range Zone. Based on the identified planktonic foraminifera and the described biozones, the age of the Gurpi Formation is assigned from middle Turonian to early Maastrichtian. [ABSTRACT FROM AUTHOR]

The present study interprets the carbonate stacking patterns and their depositional controls in the Upper Cretaceous strata of the Ras Budran Field in the Gulf of Suez, Egypt, on the basis of integrated well logging and a geological report provided. A set of well logs was run for two wells (RB-A2 and RB-B2), comprising gamma ray, resistivity, density, neutron, sonic, and photoelectric factor. Composite logs and geological reports were also used to help deduce the lithological and biological description of the stratigraphic units under investigation. The stacking patterns of the carbonate rocks yielded three types of electro-facies. The first facies covers the lower part of the Brown Limestone (early Campanian) and reflects a cylindrical (aggrading) stacking pattern. This facies indicates keep-up carbonate deposition in a heterogeneous facies accumulated in shallow water. The second facies covers the upper part of the Brown Limestone (late Campanian) and displays a funnel (prograding) stacking pattern. This facies indicates the depositional setting of a shallow shoreline. The third facies covers the Sudr Chalk (Maastrichtian), for which a serrated stacking pattern indicates an aggradational environment. This pattern indicates a marine depositional setting both distal and deep. Therefore, the formation and evolution of the cyclical stacking pattern of the carbonate rocks reflects variations in accommodation potential that determines the environmental changes. The evolution of these deposits is mainly attributed to a combination of eustatic sea-level fluctuations and tectonic episodes within the basin. [ABSTRACT FROM AUTHOR]

The carbonate of Khasib Formation in East Baghdad Oilfield, Central Iraq was geochemically investigated to interpret paleoredox conditions and source of rare earth elements (REEs) based on major, trace, and REEs geochemistry. SiO2 and Al2O3 concentrations are nearly the same in both wells, while CaO content just hardly differs between the EB10 and EB81 cores. The EB10 Well has higher concentrations of Th, Y, and Zr than the EB81 Well. However, both the ∑REE of EB10 (1.969-35.35, n=23) and EB81 (9.59-24.88, n=20) wells have low total REE content. These results show that the Khasib Formation's carbonate sedimentation contains seawater-like marine carbonate and PAAS-normalized REE + Y patterns accompanied by 1- light REE depletion (NdN/YbN= 0.40–0.95, n=23, and 0.54–0.90, n=20, respectively), 2- both positive to negative Ce anomalies (Ce/Ce*= 0.28-1.07, n=23; 0.39-1.76, n=20, respectively), as well as the 3- superchondritic Y/Ho ratio (23.25-57.5, n=23; 18.0-53.0, n=20, respectively). The terrigenous contribution, paleoredox conditions, and scavenging mechanisms were responsible for the observed variations in Ce components and Ce anomalies in the investigated cores. The rising U contents in the limestones (1.62-4.72 ppm) and authigenic U (0.66-4.44 ppm) indicate that dysoxic conditions were present when they were deposited. Further evidence from geochemical data suggests that diagenetic processes may be responsible for the positive Eu anomalies found in limestones. This implies that the Khasib Formation limestones may have kept their original seawater-like REE patterns. Due to trace amounts of detrital materials in certain specimens, there is identified variability in the REE + Y pattern and REE content. The current study shows that the limestones still display their original seawater-like patterns as long as shale contamination was minimal, and they act as a proxy for seawater. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous fossil vertebrate fauna of the Bajo de la Carpa Formation (Santonian), derived from several different locations in the Neuquén Basin, is relatively abundant and diverse, comprising mainly small to medium-sized reptiles, birds and fishes. The Cerro Overo – La Invernada locality (CO – LI), in the north of the basin, records a similar faunal component for that age, but stands out for its relatively greater abundance and diversity of titanosaur sauropods. The study of the materials presented here allows us to establish the presence of specimens of sauropods other than Overosaurus, the only titanosaur recorded so far in the area, the coexistence of small–medium sized forms with larger forms, which in turn represent some forms with more basal characteristics and others with more derived features. The abundance of the record of sauropods in CO – LI shows both morphological and evolutionary variations, so the discovery of more complete specimens will allow paleofaunistic, paleobiological, and paleoecological studies to be carried out. This will provide a better understanding of the role of titanosaurian sauropods in Late Cretaceous ecosystems.

Objective Red beds are widely used in palaeomagnetic studies as they can carry stable natural remanence. Most previous studies on red beds have mainly focused on lacustrine-fluvial facies, with limited targeting the aeolian red beds. Consequently, the influence of aeolian deposition processes and sedimentary environments on remanence records remains poorly understood. Methods In this study, we conducted a palaeomagnetic investigation of the red beds from the Upper Cretaceous Daijiaping Formation in the Chaling Basin, Hunan Province, China, to compare the stability and reliability of remanence in aeolian and lacustrine-fluvial red beds. Results Rock magnetic results indicate that magnetite, maghemite and hematite are the dominant magnetic remanence carriers. Specimens were subjected to stepwise thermal demagnetization, and only 1/6 of the specimens yielded characteristic remanent magnetisations (ChRMs). Although the mean directions of ChRM in both aeolian(Ds=222.7°, Is=-43.3°, κ=5.9, α95=20.6°, n=11) and lacustrine-fluvial (Ds=204.6°, Is=-47.8°, κ=2.4, α95=23.1°, n=28) samples are statistically indistinguishable, the distribution of individual ChRM directions is scattered, as evidenced by the large α95 values. Thin section observation reveals that the aeolian samples are predominantly composed of fine grains, with some coarser grains and almost no interstitial fillings compared with the lacustrine-fluvial red beds. This makes them susceptible to physical disturbance and subsequent chemical alteration, which compromises the stability of their remanence records. Analysis of palaeomagnetic data of specimens from different positions of an aeolian foreset bed reveals that the reliability of remanence is significantly influenced by aeolian depositional processes in case the angle between the foreset bed and the bedding plane is larger than 20°. Statistical analysis of palaeomagnetic data previously published from the Cretaceous red beds in South China and these in this study suggests that the remanence records in the Cretaceous aeolian red beds in South China tend to be less stable and less reliable, compared with that of the coeval lacustrine-fluvial red beds. It is probably because of their loose structure and low hematite content, which hinders the acquisition of primary remanence and makes them susceptible to diagenetic alteration. Conclusion These findings provide valuable insights for studying the stability and reliability of remanence in aeolian red beds and their application in palaeomagnetic study.

The Maastricht Formation is a mostly calcarenitic unit that belongs to the Chalk Group but is unlike the typical North Sea chalk in that it is much coarser and at times contains a significant terrigenous component. The formation was deposited between the late Maastrichtian and the early Danian in a proximal zone of the Chalk Sea immediately north of the Anglo-Brabant and Rhenish massifs. The formation crops out in South Limburg, the Netherlands, in the German state of North Rhine–Westphalia, near Aix-la-Chapelle (Aachen), and in the Belgian provinces of Liège and Limburg, and it is present in the subsurface in the Campine Basin and in the Roer Valley Graben, in Belgium and the Netherlands.

Grain size analysis, heavy mineral analysis, and petrographic studies of sandstones of the Ajali Formation near Imoru (south of the Ifon), the western flank of the Anambra Basin, were conducted to determine the provenance and depositional environment. The textural attributes of the Ajali Sandstone were inferred from the statistical variables namely graphic mean, graphic kurtosis, inclusive graphic standard deviation (sorting), inclusive graphic skewness with values of 0.37 - 1.17 (average 0.55Ø), -9.84 - 3.07 (average 0.09Ø), 0.05 - 1.02 (average 0.75Ø), and -0.03 - 1.00 (average 0.35Ø) respectively. Bivariate plots, such as simple skewness measure versus standard deviation (sorting) and mean versus sorting, suggest that the Ajali Sandstone is mainly a fluvial environment. The petrographic result indicates that quartz is the dominant detrital component with iron oxide, and hematite and goethite are the major cement in the analyzed sandstone sample. The zircon–tourmaline–rutile (ZTR) indices range from 67.65% to 73.17%, indicating that the sandstones are sub-mature to mature. Provenance indicators support igneous rocks of acidic compositions (e.g., granite) and high-grade metamorphic rocks (e.g., granite gneiss) of the Basement Complex of Southwestern Nigeria.

The ichnological study of the Djebel Bouarif Cenomanian deposits (Northern Aurès Range, Algeria) revealed relatively abundant and diverse sclerobiont communities that are preserved in corals, bivalves and gastropods. Fossil traces are dominated by exceptionally preserved Gastrochaenolites, often with tracemakers (bivalves), which are preserved in situ, Entobia, and Maeandropolydora. Other borings are rare and are represented by a single specimen of Rogerella, Nihilichnus, and Spirolites. Among sclerozoans, encrusting juvenile oysters and non-oyster bivalves (Pseudolimea? granulata) are the most abundant groups. Other epibionts, such as gastropods and polychaetes (Glomerula serpentina), are less common; dwarf gastropods were located on a single oyster Costagyra olisiponensis, whereas Glomerula specimens were clustered on the lower and upper surfaces of coral Aspidiscus cristatus. Gastrochaenolites with original tracemakers and all the epibionts studied herein have not been described from the Djebel Bouarif Cenomanian deposits to date. The rare occurrences of Spirolites and Nihilichnus are reported from Algeria for the first time. [ABSTRACT FROM AUTHOR]

Marine mudstone of Coniacian age (c. 89.51-86.49 Ma) was deposited on a storm-dominated ramp spanning the foredeep of the Cretaceous Western Canada Foreland Basin. Marine flooding surfaces define 18 allomembers that thin over 300 km, from c. 140 m in the proximal foredeep to c. 20 m close to the forebulge crest. The broadly conformable succession of allomembers is partitioned into five 'tectono-stratigraphic units' by low-angle unconformities that bevel off c. 10 to 20 m of strata over 'arches' that have a length scale of c. 50-100 km and are bounded by relatively linear zones of flexure. Depositional history involved two alternate modes: 'Background' deposition of subtly-tapered allomembers took place on a planar sea floor, subject to regional flexural subsidence, with sea-level modulated by Milankovitch-scale (c. 125 kyr) eustatic cycles. 'Flexural' events deformed the strata into troughs and arches across narrow zones of flexure. Arch crests were bevelled off, probably by submarine wave erosion. Eroded sediment did not accumulate in troughs but was advected beyond the study area by storm-driven processes. Cycles of deposition, warping and erosion were repeated five times on an average timescale of 600 kyr. Arches and troughs do not coincide with Precambrian basement structures, and their origin remains enigmatic. Changes in in-plane stress may have effected the localized vertical motion. [ABSTRACT FROM AUTHOR]

Upper Cretaceous ammonites are described from six horizons in the mammal-bearing terrigenous-clastic sequences of western Uzbekistan, as follows: Upper Cenomanian, with Placenticeras sp. juv. cf. cumminsi Cragin, 1893 and Metoicoceras geslinianum (d'Orbigny, 1850); Lower Turonian with Tragodesmoceras cf. mauryae Kennedy and Wright, 1981, Placenticeras kharesmense (Lahusen, 1884), Watinoceras coloradoense (Henderson, 1908), Watinoceras amudariense (Arkhangelsky, 1916b), Metasigaloceras rusticum (J. Sowerby, 1823), Morrowites wingi (Morrow, 1935), Sciponoceras cf. bohemicum bohemicum (Fritsch, 1872), and Yezoites amudariensis (Arkhangelsky, 1916b); Middle Turonian with Collignoniceras woollgari woollgari (Mantell, 1822); Upper Turonian with Lewesiceras mantelli (Wright and Wright, 1951) and Placenticeras crassum Ilyin, 2020; a single Placenticeras semiornatum (d'Orbigny, 1850) from around the Coniacian/Santonian boundary, and Santonian Placenticeras polyopsis (Dujardin, 1837). [ABSTRACT FROM AUTHOR]

Jiangxititan ganzhouensis gen. et sp. nov. is a new titanosaurian sauropod recovered from the Upper Cretaceous (Maastrichtian) Nanxiong Formation of Jiangxi Province, southern China. It is characterised by: (1) posterior cervical and anterior dorsal centra strongly compressed dorsoventrally; (2) accessory horizontal laminae present within the anterior dorsal pleurocoels; (3) posterior cervical and anterior dorsal neural arches low; (4) posterior cervical and anterior dorsal neural spines deeply bifurcated and widely separated; (5) inverted ‘V’ lamina formed by the left and right medial spinoprezygapophyseal laminae present at the anterior margin of the bifid point in posteriormost cervical and anteriormost dorsal neural spines; (6) triangular fossa formed by the metapophysis, medial and lateral spinoprezygapophyseal laminae present at the anterior margins of the posteriormost cervical and anteriormost dorsal neural spines; (7) postzygapophyses in the posterior cervical vertebrae fan-shaped; (8) medial and lateral spinopostzygapophyseal laminae present in the anterior dorsal vertebrae; and (9) anterior dorsal rib short and gracil. Our phylogenetic analysis places Jiangxititan within the deeply-nested titanosauriform clade Lognkosauria and the sympatric Gannansaurus in a much earlier-diverging lineage. This new discovery thus demonstrates the presence of both early-diverging and late-diverging titanosauriform sauropods in the Late Cretaceous Ganzhou dinosaur fauna. [ABSTRACT FROM AUTHOR]

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This study is conducted on the Northern Borders Province, northernmost Saudi Arabia, mapping a newly identified Wadi Al Khirr transtensional fault zone, based on detailed fieldwork, image interpretation as well as GIS work. The Wadi Al-Khirr fault zone extends from west of Al Uwayqilah to Zahwah. Remote sensing satellite data indicate that it can be projected further to the south toward the central Arabian Shield. About 100 km to the east of the newly proposed fault zone, late Cretaceous Linah Formation is changing its eastern lithofacies within the Widyan basin. The changes in lithofacies represent the results of tense diagenetic alteration (many phases of dolomitization/de-dolomitization), accompanied by silicification and carbonate leaching of the carbonate rocks. This western (Mediterranean) and eastern (Arabian Gulf) lithofacies appear to be laterally equivalent in biostratigraphy as it is evidently having Loftusia sp. in both sides. The lithofacies changes occur 100 km to the east of the Wadi Al Khirr fault zone; therefore, it is likely postdating the Upper Cretaceous sequences and may not be associated tectonically with the east to west lithofacies. The Sirhan–Turayf and Widyan basins' boundary is found in this study to have complicated tectonic setting. Wadi Al Khirr fault zone to the east, and the Makkah-Madinah-Nafud with newly interpreted Sakaka lineaments to the west bound the Ha'il arch, separating the two basins. Moreover, the Ha'il arch is cross-cut and deformed by Ar'Ar arch in the upper northern part of the study area and by reactivation of Najd Faults to the south. [ABSTRACT FROM AUTHOR]

Numerous representatives of the genus Patellula Kozlova, 1972 were studied from the Upper Cretaceous deposits of Perapedhi, Kannaviou and Lefkara formations (Cyprus). Two new species were described: Patellula mangaleniensis sp. nov. and Patellula solaris sp. nov. The species P. mangaleniensis was found in Crimea within the Afens perapediensis Zone (upper part of the Upper Santonian). The earliest representatives of Patellula euessceei Empson-Morin, 1981 were for the first time found in the Upper Cretaceous of Crimea, within the Actinomma (?) belbekense Zone (upper part of the Middle Turonian–Upper Turonian), while the latest representatives of P. euessceei were for the first time detected in the Maastrichtian of Cyprus. The stratigraphic ranges of Patellila euessceei and the genus Patellula are expanded. [ABSTRACT FROM AUTHOR]

The study of microfacies, with special emphasis on the significance of larger benthic foraminifera, is used to interpret the occurrence of different marine subenvironments into a mixed carbonate-siliciclastic platform from the upper Campanian in the Prebetic domain, representing the southeastern margin of the Cretaceous Iberian paleoisland. Four foraminiferal assemblages have been recognized, each one specifically assigned to a depositional systems: (1) the outer to middle shelf with Neorotalia? pinetensis, Goupillaudina spp., gavelinellids, Orbitoides tissoti-media, Praesiderolites douvillei, and Navarella joaquini; (2) the upper part of the middle shelf with the presence of seagrass meadows Orbitoides tissoti-media, "Orbitoides" concavatus, Lepidorbitoides campaniensis, Planorbulina cretae, Sirtina ornata, Praesiderolites douvillei, Pseudosiderolites vidali, and Rotalia baetica; (3) the upper photic zone of the inner shelf, with constant wave agitation, inhabited by Orbitoides cf. megaloformis, Lepidorbitoides campaniensis, and Wannierina vilavellensis; and (4) the paralic shallow protected shelf with alternating marine/freshwater influences characterized by charophytes and Suturina minima. Results on larger foraminifera distribution show the similarities and differences with the benthic communities shallow water platform assemblages of the nearby Pyrenean paleobioprovince. This allows to rise the Upper Cretaceous shelfs of the Betic area as a fundamental biogeographic piece for larger benthic foraminifera migration patterns between the Tethyan domain and the other marine domains during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

We analysed the stable isotope compositions of dinosaur eggshells and their associated depositional settings of the egg-bearing rocks in the Upper Cretaceous of the Qiyunshan area, Anhui Province, China. Data show that δ13C values for Similifaveoloolithus qiyunshanensis and Umbellaoolithus xiuningensis range between −5.94‰ and −3.55‰; this suggests that C3-type vegetation was consumed by dinosaurs with relatively high atmospheric CO2. δ18O values vary between −8.45‰ and −4.95‰, indicative of high temperature and low humidity within nesting areas. The lithological characteristics of the egg-bearing section evaluated in this study are dominated by red-brown fine sandy siltstone, correlating with pebbly medium-fine grained and medium-fine grained lithic sandstones. Grain size parameters, histograms, and sample probability cumulative curves are also all characterised by fine-grained sediments and suspension populations, likely indicative of floodplain and point bar environments. Therefore, the paleoclimate of the dinosaur nesting habitat was semiarid-to-arid based on food types as well as the colour and high Fe content of sediments. We suggest that this fluvial environment provided the best nesting and egg laying area for drought-adapted dinosaurs in the Upper Cretaceous of the Qiyunshan area and that the excavated nesting could be concluded in view of the periodic flooding events. [ABSTRACT FROM AUTHOR]