Planktic foraminiferal biostratigraphy of the Maastrichtian-Paleocene succession at the north Farafra Oasis,Western Desert,Egypt

Seven planktic foraminiferal zones are distinguished in the Maastrichtian-Paleocene succession at the north Farafra Oasis. These are the Rugoglobigerina hexacamerata (CF8b), Gansserina gansseri, and Contusotruncana contusa zones in the Maastrichtian topped by a well-known unconformity across the Cretaceous/Paleogene (K/Pg) boundary. The Danian is subdivided into two biozones: Globanomalina compressa/Praemurica inconstans-Praemurica uncinata Subzone (P1c) and Praemurica uncinata–Morozovella angulata (P2) Zone. The Late Paleocene is divided into two zones: Morozovella angulata-Globanomalina pseudomenardii (P3) and Globanomalina pseudomenardii (P4). A minor hiatus between the Danian/Selandian and Selandian/Thanetian boundaries are also recorded. These time gaps across the stage boundaries may be related to the tectonic events that affected the sedimentation regime throughout the Upper Cretaceous–Lower Paleogene interval in the Farafra Oasis.     

Late Cretaceous–Early Paleogene tectonic events at Farafra-Abu Minqar Stretch,Western Desert,Egypt: results from calcareous plankton

This work depends on integrated high-resolution calcareous plankton nannofossil and foraminiferal biostratigraphic analyses for three Upper Cretaceous-Lower Paleogene successions at Farafra-Abu Minqar area, Western Desert, Egypt. These sections are distributed in a north-south geologic profile as follows: El Aqabat, North Gunna, and Abu Minqar. Lithostratigraphically, four formations are recorded in the study area, namely, Khoman (at base), Dakhla, Tarawan, and Esna (at top). In the north at El Aqabat section, Khoman Formation (carbonate facies) is only represented which changes partially toward the south to Dakhla Formation (siliciclastic facies). In the extreme south at Abu Minqar section, it changes completely into siliciclastic facies of Dakhla Formation. Biostratigraphically, seven calcareous nannofossil and eleven planktonic foraminiferal zones represent the Late Cretaceous-Early Paleogene are identified. Based on the occurrence or missing of these zones accompanied with the field criteria resulted in detecting four tectonic events. These tectonic events took place at the Cretaceous/Paleogene (K/Pg), the Danian/Selandian (D/S), the Selandian/Thanetian (S/T), and the Paleocene/Eocene (P/E) boundaries. These tectonic events are related to the impact of the Syrian Arc System. Four sequence boundaries (SB1, SB2, SB3, and SB4) are defined in the Late Cretaceous-Early Paleogene sequence in the Farafra-Abu Minqar area.     

Planktonic foraminiferal biostratigraphy and faunal turnover events during the Late Cretaceous-Early Tertiary along the Red Sea Coast, Egypt

Planktonic foraminiferal assemblages from the Late Cretaceous-Early Tertiary sedimentary sequence in Quseir (Hammadat section), Safaga (Wasif section) and Esh El-Mellaha (Esh El-Mellaha section) areas along the Red Sea Coast, provide a database for biostratigraphical subdivisions and marking of faunal changes. Ten planktonic foraminiferal zones were found. There are, from base to top, the Late Cretaceous Globotruncana ægyptiaca and Gansserina gansseri Zones and the Early Tertiary Parasubbotina pseudobulloides, Praemurica trinidadensis, P. uncinata, Morozovella angulata, Igorina pusilla, Globanomalina pseudomenardii, Morozovella velascoensis and M. edgari zones.Two intervals of non-deposition of sediments (hiatuses) in the study areas are recorded, indicating tectonic events. The first hiatus occurred all over the study areas near the Cretaceous/Tertiary boundary. The second hiatus is restricted to the Late Palæocene of the Safaga area.Two global planktonic foraminiferal faunal turnover events are identified, reflecting major palæoceanographic changes. The faunal turnover event I occurred near the M. angulata/I. pusilla boundary near the Palæocene/Eocene boundary. These turnovers are characterised by the appearance and disappearance of species and changes in relative abundance, diversity and richness of species. Oscillation in the mean sea level in the study areas during the Late Cretaceous-Early Tertiary may be related to a true eustatic change in addition to the evidence for local tectonic control.     

Maastrichtian carbon cycle changes and planktonic foraminiferal bioevents at Gebel Matulla,west-central Sinai,Egypt

Comparison between the planktonic foraminiferal bioevents from different palaeolatitudes suggests that the biostratigraphic criteria used to identify the Maastrichtian stage boundaries are problematic. A new high-resolution calibration of planktonic foraminiferal biostratigraphic, carbon-isotope, and sequence-stratigraphic criteria has been recorded for the first time from the Maastrichtian Sudr Formation at Gebel Matulla, west-central Sinai. The sedimentary successions allow the identification of prominent long-term carbon isotope events in the Maastrichtian, namely the negative excursion of the Campanian–Maastrichtian Boundary Event (CMBE), the positive excursion of the mid-Maastrichtian Event (MME), and the decline towards the Cretaceous-Palaeogene transition (KPgE). Termination of these well known δ¹³C events is associated with unconformities, created by eustatic sea-level changes, although the long duration argues for superimposed local tectonic control.     

Enregistrement de phénomènes de resédimentation au cours du Maastrichtien supérieur et du Paléocène supérieur (J. Serj, Tunisie atlasique) : apport micropaléontologique et signature tectono-eustatique

Sedimentological and biostratigraphic analysis of Campanian–Maastrichtian reduced series of the J. Serj permitted to characterize two episodes of submarine erosion. The first is pre-Upper Maastrichtian (Rosita contusa zone), the second is pre-Upper Palaeocene (Morozovella velascoensis zone). Thus, two type-1 boundary surfaces are distinguished. These surfaces limit three stratigraphic intervals in apparent continuity. Syn-sedimentary tectonic activity is attested by gravity deposits or processes (conglomerates, slumps). To cite this article: A. Amri et al., C. R. Geoscience 337 (2005).     

Calcareous nannofossil assemblage changes and stable isotope data from Maastrichtian to Selandian in the Akveren Formation,Western Black Sea,Turkey

This study is based on calcerous nannofossil assemblages changes and fluctutions of stable carbon and oxygen isotopes was collected clayey limestones, limestones, and marls in the Maastrichtian to Selandian from Akveren Formation (Western Black Sea). As the relative abundances of species of Micula spp, Watznauera barnesiae, and Arkhangelskiella cymbiformis, which tolerated changes of temperature and nutrition, carbon and oxygen isotopes compositions, and low species richness imply strong diagenesis effect at the Maastrichtian, there is no important diagenesis effect at Paleocene. Just after the Cretaceous/Tertiary (K-Pg) boundary, Thoracosphaera spp. and Braarudosphaera bigelowi were dominant species; Danian is characterized by Thoracosphaera, Ericsonia ovalis, Cruciplacolithus spp., Coccolithus pelagicus, and Ericsonia subpertusa. Generally, the nutrition productivity is good–moderate in Lower Maastrichtian, and decreasing carbon isotope values during the Uppermost Maastrichtian shows the presence of oligotrophic environmental conditions suitable with global nutrition crises before the K-Pg boundary and diagenesis in study area. Throughout the Danian, mesotrophic–oligotrophic environmental conditions dominate; however, the decrease in nutrition before Selandian represents oligotrophic environmental conditions. The increasing nutrition at Selandian is related to the change in the environmental conditions.     

First carbon isotope chemostratigraphy of the Ouled Abdoun phosphate Basin,Morocco; implications for dating and evolution of earliest African placental mammals

The well-known Maastrichtian–Ypresian vertebrate-bearing phosphate series, in the Ouled Abdoun Basin, Morocco, is classically dated using regional selachian biostratigraphic zonation. These marine sediments yielded Paleocene and Eocene mammals comprising the earliest known placentals from Africa. This study provides the first insight into the organic carbon isotope chemostratigraphy (δ¹³C_org) of the Moroccan phosphate series and a refined dating of its vertebrate-bearing levels. Four Paleocene–Eocene sections in the NE Ouled Abdoun quarries show consistent δ¹³C_org long term evolutions, from the base to the top: 1) positive trend in phosphorite Bed IIa, beginning with the lower Bone Bed yielding mammals such as Eritherium, Ocepeia, Abdounodus, Lahimia, of early Thanetian and Selandian age; 2) transitional negative trend in the Intercalary phosphorite Beds II/I that includes the Otodus obliquus and Phosphatherium escuilliei Bone Bed of earliest Ypresian age; 3) negative trend to the lowermost δ¹³C_org values that are correlative to the early–middle Ypresian interval including ETM 2 and ETM 3 hyperthermal events in the global record; 4) positive trend in chert-enriched facies containing the middle Ypresian EECO global climatic event. Our chemostratigraphic study of the Ouled Abdoun phosphate series provides a new chronostratigraphic framework for calibrating the beginning of the evolution of placental mammals in Africa. The lower Bone Bed level from the Paleocene phosphorite Bed IIa yielding Eritherium is not younger than early Thanetian, and is most likely Selandian. The Phosphatherium Bone Bed in the Intercalary Beds II/I is earliest Ypresian. The phosphorite Bed 0, from which Daouitherium probably came, is early–middle Ypresian, just below the EECO. This suggests that the first large proboscideans evolved after the PETM, during mid-Ypresian warming events. The δ¹³C_org study does not support the presence of Lutetian in the NE Ouled Abdoun phosphate series and suggests that a noticeable part of the upper Thanetian is absent.     

Calcareous Nannoplankton Biostratigraphy of the Bartin Province,Western Black Sea,Turkey

Calcareous nannoplankton biostratigraphy has been performed on five sedimentary sections through the marine Akveren Formation from the Bartin region of northern Turkey, on the southern Black Sea coast. This new biostratigraphy provides an age for the formation of the Early Campanian (nannofossil zone UC15aTP) to Early Selandian (nannofossil zone NP5), and highlights the presence of the Campanian/Maastrichtian, Cretaceous/Tertiary (K/T), and Danian/Selandian boundaries in this intermediate palaeolatitude location. Micula murus was identified below the K/T boundary, but Micula prinsii and Nephrolithus frequens were not, which implies that the K/T boundary interval is not complete in the study area. These dates are in agreement with previous micropaleontological studies.     

Biostratigraphic and biogeographic implications of a hadrosaurid (Ornithopoda: Dinosauria) from the Upper Cretaceous Almond Formation of Wyoming,USA

The results of Barnum Brown's 1937 expedition to the Almond Formation of Wyoming consisted of two unidentified ceratopsian skulls and a partial hadrosaurid specimen (AMNH 3651). The hadrosaurid is here attributed to the Maastrichtian genus Saurolophus, verifying previous biostratigraphic correlations of this formation using ammonite zones. Fossiliferous lower Maastrichtian formations occurring latitudinally between those of Alberta, Canada, and southwestern Texas, USA, such as the Almond Formation, are essential for testing the effects and duration of apparent hadrosaurid faunal segregation earlier in the Campanian, and indirectly aiding in the placement of faunal boundaries that are currently unknown for the late Campanian. The discovery of Saurolophus in Wyoming, a close relative of the Campanian genus Prosaurolophus, affirms that the segregation of hadrosaurid faunas established in the late Campanian (～75 Ma) continued for at least 3 million years. Combining occurrences of Saurolophus from Mongolia and the Moreno Formation of California with those of Alberta, Canada, this genus appears to have had one of the largest geographic ranges of any equivalent clade of hadrosaurid dinosaur, although species level distributions are still uncertain.     

Biostratigraphy of the Tethyan cretaceous successions from northwestern Zagros fold–thrust belt,Kurdistan region,NE Iraq

Nineteen benthonic and planktonic foraminiferal zones and their subzones have been recognized in the Tethyan cretaceous successions along the four sections analyzed in the northwestern Zagros fold–thrust belt within the preforeland–foreland basin. A detailed micropaleontological investigation revealed eight benthonic zones from the Qamchuqa Formation (Barremian to Lower Early Cenomanian) including: the Choffatella decipiens interval zone, C. decipiens/Palorbitolina lenticularis total range zone, C. decipiens/Salpingoporella dinarica interval zone, Mesorbitolina texana total range zone, Mesorbitolina subconcava total range zone, Orbitolina qatarica total range zone, Orbitolina sefini total range zone, and the Orbitolina concava partial range zone. The Rotalipora cushmani total range zone was recorded in the Dokan Formation that overlies the Qamchuqa Formation of the Late Cenomanian age. The Gulneri Formation is represented only by the Whitnella archaeocretacea partial range zone/Heterohelix moremani total range subzone and indicates the Late Cenomanian/Early Turonian age. Six planktonic foraminiferal zones were recorded from the Kometan Formation, indicating the Late Cenomanian to Early Campanian age, and are represented by the R. cushmani/H. moremani subzone, Helvetotruncana helvetica total range zone, Marginotruncana sigali partial range zone, Dicarinella primitiva interval range zone, Dicarinella concavata interval zone, Dicarinella assymetrica total range zone, and Globotruncanita elevata partial range zone. Two planktonic foraminferal zones were recorded also and these are related to the Globotruncana (fornicata, stuartiformis, elevata, and ventricosa) assemblage zone, Globotruncana calcarata total range subzone, from the Shiranish Formation, Lower Late Campanian, while the second zone is nominated as the Globotruncana (arca, tricarinata, esnehensis, and bahijae) assemblage zone, Globotruncana gansseri interval subzone, and Globotruncana contusa total range zone of the Late Campanian to basal middle Maastrichtian age. The last zone is related to the Abathomphalus mayaroensis partial range zone (of Late Maastrichtian age) and occasionally intercalated with the Orbitoides–Loftusia benthic zones. An important hiatus, between the Qamchuqa and Kometan formations was proved and manifests Pre-Aruma unconformity, and is occasionally associated with the global Cenomanian–Turonian Oceanic Anoxic Euxinic Event, while the Maastrichtian red bed of the Shiranish Formations mostly points to Tethyan upper Cretaceous Oceanic Red Bed.     

Calcareous nannofossils biostratigraphy of the Late Campanian–Early Maastrichtian Age, Block 16, Jiza’-Qamar Basin, Eastern Yemen

One hundred and thirty nine samples have been studied from the Late Campanian–Early Maastrichtian of three deep wells drilled in Jiza’-Qamar Basin, Eastern Yemen to determine the calcareous nannofossil zones and the age of the sediments. Forty-seven calcareous nannofossil species were identified and four biozones were determined in the present study (CC21–CC24). These biozones are assigned to the Late Campanian–Early Maastrichtian ages. Most of the studied species in this work refer to tropical–subtropical environment. The Campanian–Maastrichtian Boundary was determined in Al-Fatk well based on the last occurrence of Eiffelithus eximus and the last occurrences of Uniplanarius sissinghii and Uniplanarius trifidus.     

Palynostratigraphy and palaeoenvironmental significance of the Cretaceous palynomorphs in the Qattara Rim-1X well,North Western Desert,Egypt

Palynological and palynofacies analyses were carried out on some Cretaceous samples from the Qattara Rim-1X borehole, north Western Desert, Egypt. The recorded palynoflora enabled the recognition of two informal miospore biozones arranged from oldest to youngest as Elaterosporites klaszii-Afropollis jardinus Assemblage Zone (mid Albian) and Elaterocolpites castelainii–Afropollis kahramanensis Assemblage Zone (late Albian–mid Cenomanian). A poorly fossiliferous but however, datable interval (late Cenomanian–Turonian to ?Campanian–Maastrichtian) representing the uppermost part of the studied section was also recorded. The palynofacies and visual thermal maturation analyses indicate a mature terrestrially derived organic matter (kerogen III) dominates the sediments of the Kharita and Bahariya formations and thus these two formations comprise potential mature gas source rocks. The sediments of the Abu Roash Formation are mostly dominated by mature amorphous organic matter (kerogen II) and the formation is regarded as a potential mature oil source rock in the well. The palynomorphs and palynofacies analyses suggest deposition of the clastics of the Kharita and Bahariya formations (middle Albian and upper Albian–middle Cenomanian) in a marginal marine setting under dysoxic–anoxic conditions. By contrast, the mixed clastic-carbonate sediments of the Abu Roash Formation (upper Cenomanian–Turonian) and the carbonates of the Khoman Formation (?Campanian–Maastrichtian) were mainly deposited in an inner shallow marine setting under prevailing suboxic–anoxic conditions as a result of the late Cenomanian and the Campanian marine transgressions. This environmental change from marginal to open (inner shelf) basins reflects the vertical change in the type of the organic matter and its corresponding hydrocarbon-prone types. A regional warm and semi-arid climate but with a local humid condition developed near/at the site of the well is thought to have prevailed.     

Fault-controlled stratigraphy of the Late Cretaceous Abiod Formation at Ain Medheker (Northeast Tunisia)

The palaeogeographic setting of the studied Ain Medheker section represents an Early Campanian to Early Maastrichtian moderately deep carbonate shelf to distal ramp position with high rates of hemipelagic carbonate production, periodically triggered by mass-flow processes. Syndepositional extensional tectonic processes are confirmed to the Early Campanian. Planktonic foraminifera identified in thin sections and calcareous nannofossils allow the identification of the following biozones: Globotruncanita elevata, Contusotruncana plummerae (replacing former Globotruncana ventricosa Zone), Radotruncana calcarata, Globotruncana falsostuarti, and Gansserina gansseri. The following stable C-isotope events were identified: the Santonian/Campanian boundary Event, the Mid-Campanian Event, and the Late Campanian Event. Together with further four minor isotopic events, they allow for correlation between the western and eastern realms of Tunisia. Frequently occurring turbidites were studied in detail and discussed in comparison with contourites.     

A neoselachian shark fauna from the Late Cretaceous of Senegal

A selachian fauna is described for the first time from the Late Cretaceous (Campanian–Maastrichtian) of Senegal. So far, the Campanian Paki Formation has only yielded a single tooth of Rhombodus sp. whereas the Cap de Naze Formation has yielded a more diverse fauna including juvenile Cretalamna cf. Cretalamna biauriculata, Serratolamna serrata, Carcharias cf. Carcharias heathi, ?Carcharias sp., Squalicorax pristodontus, Schizorhiza stromeri, Parapaleobates sp., Rhombodus binkhorsti and Rhombodus andriesi. Teeth of juvenile Cretalamna largely dominate the assemblage. Such an assemblage confirms a Late Maastrichtian age for the unit 3 in the Cap de Naze Formation. The assemblage, although composed of cosmopolitan taxa, is similar to the contemporaneous selachian assemblage from the phosphates of Morocco.     

Calcareous nannofossil biostratigraphy of the Paleocene at the Misheiti section,East Central Sinai,Egypt

Integration of calcareous nannofossil data, δ¹³C and δ¹⁸O values, and carbonate contents of the lower Paleocene–upper Paleocene sequence that crops out at the Misheiti section, East Central Sinai, Egypt, were used to denote the Danian/Selandian (D/S) and Selandian/Thanetian (S/T) stage boundaries. The study interval belongs to the Dakhla and Tarawan formations. Four calcareous nannofossil zones (NP4, NP5, NP6, and NP7/8) were recognized. The base of the Selandian Stage is tentatively placed at the lowest occurrences (LOs) of taxa ascribable to the second radiation of fasciculiths (i.e., Lithoptychius janii). This level is marked by a sudden drop of δ¹³C and δ¹⁸O values and carbonate content. No distinctive lithological changes were observed across the D/S boundary at the study section. A hiatus at the NP5/NP6 zonal boundary is indicated by the condensation of zones NP5 and NP6.The base of the Thanetian is placed at the base of Zone NP7/8 at the lithological change observed in correspondence to the boundary between the Dakhla and Tarawan formations. The δ¹³C and δ¹⁸O values abruptly decrease slightly above the base of Zone NP7/8. No consistent variations in the carbonate contents were recorded within Zone NP6 or across the NP6/NP7/8 zonal boundary.     

Sequence stratigraphy of Aqra Formation (Late Upper Campanian–Maastrichtian) in Geli Zanta corge,Northern Iraq

The Aqra Formation represents a succession that was deposited over most of Northern Iraq and adjacent regions. In north Iraq, in the core of NW–SE trending Aqra anticline, a 438-m-thick section of the Aqra Formation crops out at Geli Zanta corge. The base of the Aqra Formation is not exposed here. The upper contact is unconformably overlain by Paleocene–Lower Eocene formations (Kolosh and Khurmala formations). A hundred and one samples were collected from the section and used for biostratigraphic and microfacies analysis. According to the occurrence of larger Foraminifera (Orbitoides media and Orbitoides apiculata) and planktonic Foraminifera (Abathomphalus mayaroensis), Late Upper Campanian–Maastrichtian age was determined for Aqra Formation. Fifteen facies were distinguishable throughout the formation, representing tidal flat (supratidal), restricted marine shelf (lagoon) and shelf margin rudist reef, and its related debris. These environments were used to interpret three depositional sequences which correlate with those of Aruma Formation (KSA), Simsima Formation (UAE) in Arabian Plate, and with Iraqi formation sequences. Three maximum flooding surfaces were recognized as MFS 175, MFS 180, and MFS 190.     

Latest Campanian and Maastrichtian Siderolitidae (larger benthic foraminifera) from the Pyrenees (S France and NE Spain)

The siderolitids from the uppermost Campanian and Maastrichtian deposits of the Pyrenees have been re-studied. This has revealed a high diversity and rapid replacement of taxa, confirming the group as a good tool for high resolution biostratigraphy. Two genera have been found in the uppermost Campanian–Maastrichtian interval in the Pyrenean deposits: Siderolites Lamarck, and Wannierina Robles-Salcedo. Siderolites, with canaliferous spines or denticulate periphery, is represented by four species replacing each other from the latest Campanian to Maastrichtian: Siderolites praecalcitrapoides (latest Campanian), S. pyrenaicus sp. nov. (early Maastrichtian), Siderolites calcitrapoides (late Maastrichtian) and Siderolites denticulatus (late Maastrichtian). Wannierina is characterised by well-developed keels and ramified marginal canals. Two species of Wannierina have been identified and they succeeded one another from latest Campanian to early Maastrichtian: Wannierina vilavellensis sp. nov. (latest Campanian) and Wannierina cataluniensis (early Maastrichtian). The species of the genus Siderolites inhabited shallow waters of tropical to subtropical platforms with moderate-to-high water-energy conditions and those of the genus Wannierina are typical of deep–water low-energy environments but still in the eutrophic zone.     

Stratigraphy of Upper Cretaceous and Cenozoic deposits of the Bakchar iron ore deposit (southwestern Siberia): New data

The results of complex palynological and microfaunistic studies of Upper Cretaceous and Cenozoic deposits of the Bakchar iron ore deposit are presented. Geochronologically, the age of the deposits varies from Campanian to Quaternary. It was established that the Slavgorod, Gan’kino, and Jurki (?) formations contain four biostratons in the rank of beds with dinocysts and three biostratons in the rank of beds with spores and pollen. The Cenozoic continental deposits contain four biostratons in the rank of beds, containing spores and pollen. As a result of the study, a large stratigraphic gap in the Cretaceous–Paleogene boundary deposits, covering a significant part of the Maastrichtian, Paleocene, Ypresian, and Lutetian stages of the Eocene, was established. The remnants of a new morphotype of heteromorphic ammonites of genus Baculites were first described in deposits of the Slavgorod Formation (preliminarily, upper Campanian). The distribution features of the different palynomorph groups in the Upper Cretaceous–Cenozoic deposits in the area of study due to transgressive-regressive cycles and climate fluctuations were revealed.     

A new species of Pluridens (Mosasauridae: Halisaurinae) from the upper Campanian of Southern Nigeria

The Upper Cretaceous of Africa has produced a diverse fauna of mosasaurs, including the highly specialized, long-jawed Pluridens. The type of Pluridens walkeri comes from the Maastrichtian Farin-Doutchi Formation of Niger, with a second, referred specimen coming from the Campanian section of the Campanian-Maastrichtian Nkporo Shale near Calabar, in southern Nigeria. Comparisons of this referred specimen with the holotype suggest that it represents a distinct and more primitive species. The Calabar jaw resembles P. walkeri in being long and narrow anteriorly with a shallow subdental shelf, and in having small, numerous, recurved teeth with medially positioned replacement pits. However, it lacks many of the derived features that characterize Pluridens walkeri, such as the extremely long and straight jaw, the extreme lateral protrusion and subcircular section of the dentary, strong transverse expansion of the dental thecae, and extreme reduction and increase in number of the teeth. The Calabar Pluridens is therefore referred to a new species, Pluridens calabaria. Following recent studies, Pluridens is considered to represent a highly derived member of the Halisaurinae. The marked differences between the Campanian and Maastrichtian species of the genus underscore the rapid pace of mosasaur evolution during the Cretaceous.