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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]

AbstractThe Sarvak Formation, with a total thickness of 1566 m and major limestone lithology in the Ahvaz and Mansouri oil fields, is studied to determine its palaeoenvironment, diagenetic overprint and geochemistry. In the studied wells, the formation conformably overlies the Kazhdumi Formation and is overlain by the Ilam Formation. The petrographical studies led to identifying twelve facies precipitated in four major sub-environments, including inner-, middle-, and outer ramp and an intra-shelf basin on a homoclinal ramp-type setting. Dissolution, compaction, and cementation are the main diagenetic alterations that changed the primary chemical composition and the reservoir property of the Sarvak Formation. These diagenetic processes occurred in phreatic marine, meteoric, and burial realms. Sedimentary geochemistry of major and trace elements, including Ca, Mg, Fe, Mn, and Sr, along with O and C stable isotopes, reveal aragonite as the original carbonate mineralogy of the Sarvak Formation. The depositional environment in the lower Sarvak with the predominant shallow open marine and stratigraphic succession with no evidence of exposure, change to stratigraphic succession with more shallow sub-environments (lagoon and bioclastic-shoal), and the evidence of exposure such as cementation and extensive dissolution, which led to depletion in Sr, δ18O, and δ13C and enrichment in Fe and Mn during sea level fall in the inner ramp microfacies. The Fe and Mn cross-plot with a positive trend shows the effects of diagenetic phases in minor phreatic marine and mainly meteoric realm, all confirmed by petrography. The Sr/Ca ratio has the most correlation to the modern tropical warm-water shallow marine that could confirm the primary aragonite mineralogy; which is supported by the predominance of carbonate mud in the identified facies, primary isopachous fibrous marine cements, and extensive dissolution evidence. The cross-plot of Fe versus Sr and Mn versus Sr/Mn ratio suggests deposition in mainly an oxygenation state that experienced low to high water/rock interaction during different depositional sequences. The δ18O and δ13C co-variation and their comparison with the other fields of the Sarvak conducted in different regions show precipitation in an isotopic equilibrium in the carbonates with the Upper Cretaceous seawater, since calculating salinity (Z=130) and temperature (T= 26°C) of the Sarvak Formation confirm the above statement.Keywords: Diagenesis, Sedimentary geochemistry, Water/rock interaction, Upper Cretaceous, Sarvak Formation. Introduction:The Albian–Turonian Sarvak Formation (Motiei 1993), which forms a part of the Bangestan Group the second most important reservoir succession in the Zagros Basin and Persian Gulf (Esrafili-Dizaji et al. 2015; Assadi et al. 2016). This succession is equivalent to Mishrif, Ahmadi and Rumaila in Saudi Arabia, Natih in Oman, Derder in Turkey, and Mishrif in Iraq, which was deposited on a shallow carbonate platform along with interashelf basins on the passive margin of the Arabian Plate (Ziegler 2001; Piryaei et al. 2011; Alsharhan 2014). Various studies conducted on the geochemistry of carbonates reveal its adequacy in determining palaeoclimate and original mineralogy, defining the rate and type of diagenetic alteration, distinguishing diagenetic realms and trends as well as the stratigraphic position of depositional sequence stratal surfaces and boundaries (Adabi and Asadi Mehmandosti 2008; Crowe et al. 2013; Fallah-Bagtash et al. 2020; Omidpour et al. 2021). In this study, regarding the oil industry needs for exploration and production and based on petrographical and geochemical analysis, the facies, paloeoenvironment, diagenetic characteristics and geochemistry of the Sarvak Formation are studied in the northern Dezful Embayment, southern Iran. Material & MethodsThe facies analysis and diagenetic characteristics of the Sarvak Formation in two wells in the Ahvaz and Mansouri oil fields are studied using 900 thin sections obtained mainly from core samples. The nomenclature for carbonate rocks used in this study is the terminology introduced by Dunham (1962) and its modified classification by Embry and Klovan (1971). The facies analysis and interpretation of the depositional environments were conducted using the standard microfacies of Burchette and Wright (1992) and Flügel (2010). All thin sections were stained with potassium ferricyanide and Alizarin Red-S to distinguish carbonate minerals (Dickson 1965). The geochemical studies are done using analyzing trace and major elements including Ca, Mg, Fe, Mn, and Sr along with O and C stable isotopes of carbonate rocks both in the Exter University of England on 57 samples from the Ahvaz Oil Field and 43 samples from the Mansouri Oil Field. The trace and major elements are analyzed using Agilent 5110 VDV Inductively Coupled Optical Emission Spectrometer (ICP-OES) with 0.02 mmol/mol precision for Mg/Ca ratio, 0.4 µmol/mol for Sr/Ca ratio, 0.02 mmol/mol for Fe/Ca ratio and 0.006 mmol/mol for Mn/Ca ratio. For stable isotopes, the analysis is done using SerCon 20-22 Gas Source Isotope Ratio Mass Spectrometer (GS-IRMS) based on the Copenhagen University Standard (LEO, Carrara Marble) and with the precision of ±0.08‰ for δ13C and 0.28‰ for δ18O. Discussion of Results & ConclusionThe Sarvak Formation, with dominant limestone lithology and 831 and 735 m thickness, respectively in Ahvaz and Mansuri Oil Fields, conformably overlies the Kazhdumi Formation and is unconformably overlain by the Ilam Formation. The petrographical studies led to determinate five facies association deposited on a low angle ramp type setting along with an intrashelf basin. Diagenetic studies reveal the impact of marine, unconformity-related meteoric, and shallow and deep burial diagenesis that mainly caused intense compaction, dissolution and cementation. These main diagenetic features changed the nature of the associated facies regarding the reservoir property of the Sarvak Formation. The impact of main diagenetic features along the Sarvak succession improved the understanding of the elemental, and O and C stable isotope analyses. The geochemical analysis as well as petrographical evidences such as diversity of fauna and flora and primary marine diagenetic features confirm the original aragonite mineralogy for the Sarvak carbonate, which was formed in a warm and humid condition on a shallow marine platform. The analyzed δ18O and δ13C, along with the variable concentration of Sr, Fe and Mn suggest maintenance of the primary composition along with alteration in burial realm and mainly meteoric diagenesis. The cross-plot of trace element and O and C stable isotopes indicate that the Sarvak carbonate rocks altered in the open to close diagentic system during different depositional stratigraphic sequences depending on the exposure of the carbonate platform and its scale and duration

This paper presents the results of a comprehensive study of the Maastrichtian sequence of Mount Kyz-Kermen located in the Southwestern Crimea. The section consists of a rhythmically bedded carbonate sequence gradually replaced by carbonate sandstones. The study of rocks in thin sections made it possible to identify eight lithotypes, and the chemical analyses yielded variations in individual elements in the rock composition. The interpreted data on planktonic and benthic foraminifera made it possible to determine the age of deposits within the accuracy of zones and beds with fauna and to find one more supposed break in the middle of this section, coinciding with a noticeable change in the rock composition. The assay analysis of foraminifera assemblages together with lithological and geochemical results made it possible to determine that the studied section was formed in open carbonate-platform conditions at the depth of the middle–outer shelf. [ABSTRACT FROM AUTHOR]

The results of a comprehensive study of the boundaries of the Turonian–Coniacian in the Upper Cretaceous deposits of the Abinskii region of the Northwestern Caucasus, composed of rhythmically constructed carbonate strata of the hemipelagic type, are presented. Biostratigraphic analysis of foraminifera complexes made it possible to identify zones in the section that are comparable to those proposed for the Point of the Global Stratotype of the boundary of the Coniacian in Germany. On the basis of chemostratigraphic (isotope) studies, the levels of abiotic events traced in the section and other territories have been established. The Shapsug section, after further study, can be proposed as a possible Hypostratotype (Limitotype) of the Turonian–Coniacian boundary for the territory of the Russian Federation. [ABSTRACT FROM AUTHOR]

The results of integrated study of the Turonian–Coniacian sediments from the Abinsky district (Northwest Caucasus), which are represented by a rhythmic terrigenous-carbonate sequence, are discussed. The use of microfacial, X-ray diffraction, isotope, and micropaleontological analyses allowed us to reveal important changes in abiotic and biotic evolution during this interval. The peculiarities of carbonate sedimentation, as well as changes in the composition of foraminiferal assemblages, helped to establish fluctuations in the relative sea level, whereas isotopic studies assisted in defining climatic fluctuations. During the periods of accumulation of carbonate and clayey material, the area was occupied by a relatively deep-water open-sea basin with normal salinity. In the background of high temperatures, cooling pulses are also recorded within the studied interval. The position of the Turonian–Coniacian boundary in the section is revised. [ABSTRACT FROM AUTHOR]

Abstract In this study, the Late Cretaceous Ilam Formation of the Bangestan group in the northwest of Abdanan in the Kabir-Kuh anticline has been investigated for sedimentological and geochemical properties, and diagenetic processes. Field studies indicate that this formation in studied section reach a thickness of 281 m and composed of medium to thin-bedded limestones with shales and argillaceous limestones intercalations. The upper and lower boundaries of the Ilam Formation in the studied section are disconfirmable with the Gurpi and Sarvak formations, respectively. Based on the petrographic studies, nine microfacies and one petrofacies have been identified for the Ilam Formation which mainly deposited in the outer ramp-basin setting. The main diagenetic features affecting the Ilam Formation in the studied section include micritization, cementation, mechanical and chemical compactions, dissolution, pyritization, phosphatization, and glauconitization. Geochemical characteristic (major and trace elements) of the Ilam carbonate deposits indicate closed diagenetic system. Variations of V/Cr, V/(V+Ni) and Ni/Co indicate that the carbonate samples of the Ilam Formation are subjected to suboxic and mostly anoxic conditions. Separating the Sarvak and Ilam boundary can be aided by some geochemical data variations such as Sr/Ca, Sr/Na, Sr/Mn, Ag, V, Ni, Zn, Sr, Fe, Co and P at the Kabir-Kuh anticline in the Abdanan section. Key words: Oxic-Anoxic conditions, Sedimentary environment, Zagros, Upper Cretaceous, Diagenesis Introduction During the Cretaceous, the Zagros basin had different environmental conditions so that this variation caused lateral and vertical sedimentary facies changes and numerous source rocks and oil reservoirs were created in this basin. Therefore, the Cretaceous sequences have long been of interest to many geologists (e.g. Kashfi 1976; Bahroudi and Talbot 2003; Alavi 2004; Sepehr and Cosgrove 2004; Insalaco et al. 2006; Fakhari et al. 2008; Van Buchem et al. 2010; Agard et al. 2011; Esrafili-Dizaji and RahimpourBonab 2013; Asadi Mehmandosti et al. 2013; Spina et al. 2018). From Albian to Campanian, a large sedimentary cycle of the Kazhdumi, Sarvak, Surgah and Ilam formations can be identified in the Zagros region, called the Bangestan Group. The Sarvak and Ilam formations of this group, after the Asmari Formation, are the most important reservoir rocks in the Zagros region that are exposed in Iran and the countries around the Persian Gulf basin. In this study, an outcrop of Ilam Formation in the Kabir Kuh anticline (Abdanan section) is selected to study. The aims include: to identify lithological features, study of microfacies, diagenesis processes, identification of pale-sedimentary environment and determination of redox conditions based on Ni/Co, V/Cr and V/(V+Ni) changes. In addition, due to the lithological similarities between the Ilam and Sarvak formations and the absence of the Surgah Formation in between in the study area, precise determination of the boundaries between these two formations through geochemical data is considered. These studies can provide a detailed picture of the sedimentological status of the studied basin at the time of the Ilam Formation carbonate deposition. Material & Methods: To determine sedimentary characteristic of the Ilam Formation, 90 thin sections have been studied. Thin sections were stained with potassium ferricyanide and alizarin-red S solution (Dickson 1965). The petrographic classification for carbonates is based on the Dunham limestone classification (1962) and Embry and Klovan (1971). Flügel (2010) facies belts and sedimentary models were also used. After petrographic studies, twenty powdered micrite samples (18 samples from Ilam Formation and 2 samples from Sarvak Formation) were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) by 4-Acid Digestion method for trace, major and rare earth element contents at the Met-Solve Analytical Services Inc., BC, Canada. Discussion of Results & Conclusions Field work studies in the Kabir Kuh anticline (Abdanan section) indicate that the Ilam Formation has 281 m thickness and composed of medium to thin-bedded limestones with shales and argillaceous limestones intercalations. Based on the petrographic studies, nine microfacies and one petrofacies have been identified for the Ilam Formation as follows: MF T1: Bioclast Ooid Packstone, MF T2: Algal Bioclast Packstone, MF T3: Peloid/Benthic Foraminifera Packstone, MF T4: Bioclast Packstone, MF T5: Echinoderm Fragments Oligosteginid Packstone, MF T6: Peliodal/Planktonic Foraminifera/Oligosteginid Wackestone to Packstone, MF T7: Oligosteginid Packstone, MF T8: Planktonic Foraminifera/Oligosteginid Wackestone to Packstone, MF T9: Planktonic Foraminifera Mudstone, PF: Shale/Calcareous Shale. The Ilam Formation mainly deposited in the outer ramp- basin setting at studied section. The main diagenetic features affecting the Ilam Formation in the studied section include micritization, cementation, mechanical and chemical compactions, dissolution, pyritization, phosphatization, and glauconitization. The diagenesis sequence were effected the Ilam Formation carbonates during the three stages of eogenesis, mesogenesis and telogenesis. Investigation of geochemical data shows high amounts of Fe, V/Cr, V/(V+Ni) and Ni/Co ratios in studied carbonates and indicate that the carbonate samples of the Ilam Formation are subjected to suboxic and mostly anoxic conditions. Early pyrite observed in the Ilam Formation also indicates the abundance of iron ions in seawater and the dominance of the reductive conditions at their formation. In addition, Sr/Mn and Sr/Ca changes indicate that the Ilam Formation diagenetic system is closed in the studied section, which is in agreement with the low porosity observed in these carbonates. Therefore, with respect to the sedimentary environment, the existence of anoxic conditions at the time of formation and close diagenetic system that prevented the formation of suitable porosities in the Ilam sediments in Abdanan section, it can be concluded that this formation do not have a good reservoir quality in studied section. Separating the Sarvak and Ilam boundary can be aided by some geochemical data variations such as Sr/Ca, Sr/Na, Sr/Mn, Ag, V, Ni, Zn, Sr, Fe, Co and P at the Kabir-Kuh anticline in the Abdanan section.

The Upper Cretaceous carbonate platform deposits of Ostuni have been studied from a stratigraphical, palaeontological and palaeoecological point of view. ln the sequence studied two parts can be distinguished: the Iower one consists of stratified biomicritic limestones with clusters of rudists, other pelecypods and microfauna, represented by ostracods algae and benthonic foraminifers; the upper one consists of a sequence of coral—rudist buildups with banks of calcarenites and calcirudites characterized by trace fossil assemblages, gastropods, rudists, other pelecypods and benthonic and planktonic foraminifers.

Numerous specimens belonging to the Apulites giganteus Tavani, 1958 have been discovered in a carbonate sequence of Western Murge that belongs to the "Calcare di Altamura" unit (Upper Cretaceous). In this study both genus and type—species are reexamined and redescribed, since the discovery of the Apulian specimens has permitted new paleontological and stratigraphical observations.

Systematic study of Rudists collected from the Upper Cretaceous of Ostuni (Apulia) led to the identification of species, some recorded for the first time in this area. Special attention has been paid to Biradiolites monopterus (Pirona), found in very large number. The conspicuous number of specimens and their excellent preservation allowed us to conduct a series of observations in order to ascertain the range of morphological variability of these species.

Introduction The Basiran stratigraphic section is located about 160 km northwest of Nehbandan.The section was measured in detail at 59 06 30 N and 31 52 50 E. Nehbandan area with respect to fourfold geological subdivision of Iran is part of Central Iran that is located in the eastern flank of Lut Block which first time are studied by Stocklin et al.in 1972. Gorgij (2001) stratigraphically and paleontologically investigate Upper Cretaceous deposits in Mighan and Basiran sections. Upper Cretaceous deposits in in this area consists of 275m conglomerate,alternation of conglomerate-sandstone, sandy limestone -marl and limy marl, marl with intercalation of limestone-sandy limestone thin beds and medium-bedded to massive limestone. Microfacies analysis led to the recognition of 9 microfacies that are related to 5 belts; Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. Main part of the section are deposited in the open marine environment that consist of marl,marly limestone and limestone. The doals of this study are : (1) describing and determining main carbonate and siliciclastic microfacies of late Cretaceous deposits (2) interpreting and providing depositional model for reconstruction of its paleoenvironmental setting based on microfacies characteristics (3) dividing the section based on lithostratigraphic principles and (4) recognizing a sequence stratigraphic model of this successions based on the vertical variation of facies,stratal key beds and stratal packing pattern. Material and Method The Basiran section as a complete stratigraphic section was measured and described. Up to 68 samples (indicated by KB1 to KB68) were collected and 170 thin sections are prepared. Based on field observations, sedimentological characteristics, parasequence stacking patterns, sequence boundary types and other key stratigraphical surfaces are identified and were obtained. Scheme of Dunham (1962) and Embry and Klovan (1971) for carbonate rocks and for samples descriptions from Flugel (2004) and Wilson (1974) methods were used. Discussion of Results and Conclusions The Basiran section predominantly composed of limestone - marl in the middle and upper part and conglomerate – sandstone in the lower part. The most prominent component of carbonate sediments are larger foraminifera such as Orbitoides, Lepidorbitiodes, Siderolites, Omphalocyclus and some of pelagic foraminiferas. Systematic determination of those benthic foraminiferas suggests Late Campanian-Maastrichtian age for Basiran section. Microfacies analysis led to the Recognition of 9 microfacies that are related to 5 belts; Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. With respect to gradual shallow water facies changes, absence of barrier reef, sliding and slumping structure, cortoids, oncoids, pisoids and aggregate grains, that are abundant in rimmed shelves, several evidences shows that above mentioned carbonate are deposited in the ramp environment (Burchette & Wright 1992) . Furthermore, based on high diversity and abundance of benthose foraminiferas this environment can be considered as foram dominated carbonate ramp system ( Boxton & Pedley 1989 ) . Based on field observation, microfacies analysis and sequence stratigraphic studies, fourth third order depositional sequence (DS) in the Basiran section are identified. These depositional sequences are separated by type1 sequence boundary (lower boundary of first depositional sequence and upper boundary of fourth depositional sequence) and type 2 sequence boundary (lower boundary of 2 nd and 3 rd depositional sequence). First depositional sequence consists of LST, TST and HST and contains tidal flat, lagoon, shoal, shallow open marine and deep open marine microfacies. Lower boundary is of type 1 sequence boundary (SB1). 2 nd and 3 rd depositional sequences consist of TST and HST. Therefore contains shallow open marine and shoal microfacies and have been separated by sequence boundary type 2 (SB2). Fourth depositional sequence contains of TST and HST. Upper boundary is of type 1 sequence boundary (SB1) and terminates to with clear unconformities to Paleocene conglomerate. It is seems that both local tectonic activity and global eustasy may have controlled the third and forth order sequences and cyclicities of the Upper Cretaceous sediments in Basiran section. The SB1 in the top of the fourth depositional sequence ,which shows subaerially exposed the carbonate platform, possibly related to the widespread glacio-eustasy sea-level drop could be linked to the cooling event in the Cretaceous-Tertiary boundary(KTB).

 Introduction  The Basiran stratigraphic section is located about 160 km northwest of Nehbandan.The section was measured in detail at 59 06 30 N and 31 52 50 E. Nehbandan area with respect to fourfold geological subdivision of Iran is part of Central Iran that is located in the eastern flank of Lut Block which first time are studied by Stocklin et al.in 1972. Gorgij (2001) stratigraphically and paleontologically investigate Upper Cretaceous deposits in Mighan and Basiran sections. Upper Cretaceous deposits in in this area consists of 275m conglomerate,alternation of conglomerate-sandstone, sandy limestone -marl and limy marl, marl with intercalation of limestone-sandy limestone thin beds and medium-bedded to massive limestone. Microfacies analysis led to the recognition of 9 microfacies that are related to 5 belts Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. Main part of the section are deposited in the open marine environment that consist of marl,marly limestone and limestone. The doals of this study are : (1) describing and determining main carbonate and siliciclastic microfacies of late Cretaceous deposits (2) interpreting and providing depositional model for reconstruction of its paleoenvironmental setting based on microfacies characteristics (3) dividing the section based on lithostratigraphic principles and (4) recognizing a sequence stratigraphic model of this successions based on the vertical variation of facies,stratal key beds and stratal packing pattern.    Material and Method  The Basiran section as a complete stratigraphic section was measured and described. Up to 68 samples (indicated by KB1 to KB68) were collected and 170 thin sections are prepared. Based on field observations, sedimentological characteristics, parasequence stacking patterns, sequence boundary types and other key stratigraphical surfaces are identified and were obtained. Scheme of Dunham (1962) and Embry and Klovan (1971) for carbonate rocks and for samples descriptions from Flugel (2004) and Wilson (1974) methods were used.   Discussion of Results and Conclusions  The Basiran section predominantly composed of limestone - marl in the middle and upper part and conglomerate â sandstone in the lower part. The most prominent component of carbonate sediments are larger foraminifera such as Orbitoides, Lepidorbitiodes, Siderolites, Omphalocyclus and some of pelagic foraminiferas. Systematic determination of those benthic foraminiferas suggests Late Campanian-Maastrichtian age for Basiran section. Microfacies analysis led to the  Recognition of 9 microfacies that are related to 5 belts Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. With respect to gradual shallow water facies changes, absence of barrier reef, sliding and slumping structure, cortoids, oncoids, pisoids and aggregate grains, that are abundant in rimmed shelves, several evidences shows that above mentioned carbonate are deposited in the ramp environment (Burchette & Wright 1992) . Furthermore, based on high diversity and abundance of benthose foraminiferas this environment can be considered as foram dominated carbonate ramp system ( Boxton & Pedley 1989 ) . Based on field observation, microfacies analysis and sequence stratigraphic studies, fourth third order depositional sequence (DS) in the Basiran section are identified. These depositional sequences are separated by type1 sequence boundary (lower boundary of first depositional sequence and upper boundary of fourth depositional sequence) and type 2 sequence boundary (lower boundary of 2 nd and 3 rd depositional sequence). First depositional sequence consists of LST, TST and HST and contains tidal flat, lagoon, shoal, shallow open marine and deep open marine microfacies. Lower boundary is of type 1 sequence boundary (SB1). 2 nd and 3 rd depositional sequences consist of TST and HST. Therefore contains shallow open marine and shoal microfacies and have been separated by sequence boundary type 2 (SB2). Fourth depositional sequence contains of TST and HST. Upper boundary is of type 1 sequence boundary (SB1) and terminates to with clear unconformities to Paleocene conglomerate. It is seems that both local tectonic activity and global eustasy may have controlled the third and forth order sequences and cyclicities of the Upper Cretaceous sediments in Basiran section. The SB1 in the top of the fourth depositional sequence ,which shows subaerially exposed the carbonate platform, possibly related to the widespread glacio-eustasy sea-level drop could be linked to the cooling event in the Cretaceous-Tertiary boundary(KTB). Â

The current work used the conventional peridinioid-gonyaulacoid ratio (P/G) to devise a new concept of dinoflagellate cyst zonation called the dinoflagellate ecological zone (DEZ), which is based here on the peridinioid ecological zone (PEZ) and gonyaulacoid ecological zone (GEZ). The PEZ and GEZ were used successfully to further divide the thick monotonous carbonate succession (mid-Cenomanian to Campanian) in Q-72-1X well in the Eastern Desert of Egypt into smaller ecozones. PEZ and GEZ are practical and easy to use in subdividing large conventional biozones of the carbonate reservoirs into distinguishable, smaller ecozones when a finer resolution is necessary on a reservoir scale for production demands. This tool is suggested to be used in the hydrocarbon exploration industry with minimum knowledge of the taxonomy of the dinoflagellate cysts. The proposed PEZ and GEZ are related to local ecological conditions within the basin/hydrocarbon field (i.e. can be traced out laterally in an intra-basinal scale). This tool can be applied to any carbonate reservoirs in any petroliferous basin worldwide. Moreover, the P/G ratio, the relative abundances of the dinoflagellate cyst assemblages and other palynological parameters were used successfully to reveal the palaeodepositional settings of the identified PEZ and GEZ. Alternating, transgressive and regressive phases were identified, although a dissimilar species composition is observed in each of these ecozones. Environments were interchanging between the regressive, marginal marine to proximal inner neritic and the transgressive, distal inner to middle shelf settings. Three peridiniacean dinoflagellate cyst peaks were recorded, the middle Cenomanian Subtilisphaera peak, the middle Coniacian Isabelidinium, Chatangiella , and Manumiella peak, and the middle Santonian Isabelidinium peak. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous Aruma Formation in central Saudi Arabia is subdivided into three members. The Khanasir Member at the base is characterized by dasycladecean-rudist biofacies. The middle Hajajah Member is characterized by coral-stromatoporoid biofacies, while the upper Lina shale Member contains few badly preserved molluscs. Fifty macrofossils species have been identified from the studied section, 25 of them belong to gastropods, 17 belong to scleractinian corals, and 8 species belong to bivalves. The identified macrofossils have close affinity to Tethyan faunas and previously known from the Cretaceous rocks in Asia, Africa, and Europe. The most recorded microfacies types are wackestones, packstones, and floatstones with green algae, benthic and rare planktonic foraminifers, ostracods, and corals. The studied section revealed a major Campanian-Maastrichtian marine transgression followed the continental siliciclastics of the Wasia Formation with progressive deepening upward, from a shallow marine lagoonal environment to relatively more open marine conditions. [ABSTRACT FROM AUTHOR]

Suitable onshore analogues for offshore wind-farm turbine foundations in the Chalk of the North Sea would be invaluable. Such foundations require examples of near surface weathering illustrating both glacial and periglacial Quaternary processes as well as lithology and tectonic structure of the Chalk. From the Cenomanian to Early Campanian, the coast of East Yorkshire illustrates hard, high density, glacially eroded chalks similar to those found immediately offshore. Higher in the Campanian offshore East Yorkshire, younger, low density chalks, not present onshore, have been found (the Westermost Rough Member). In contrast, north Norfolk and its coastal cliffs provide examples of soft, high porosity, part glacially and part periglacially weathered chalks. Complex sedimentary structures seen in offshore seismic sections are similar to those on the French coast of the Pays de Caux. These coastal sections are compared with results from offshore wind farm ground investigations. Seismic sections illustrate Quaternary channels cutting into the Chalk and a landscape of hills and valleys similar to the onshore Wolds. High resolution 2D digital seismic sections, combined with cored boreholes, provide the evidence for applying the detailed Chalk lithostratigraphy to the offshore southern North Sea and illustrate the relationship between tectonic structure and sedimentation in the Chalk. The map for the offshore extension of Chalk provinces is revised, with Transitional Province lithologies typical of the Chiltern Hills and East Anglia, extending north-eastwards from Norfolk into the Dowsing Fault zone. Geotechnical properties are related to the buried offshore Chalk landscape as well as to Chalk lithostratigraphy. [ABSTRACT FROM AUTHOR]

A set of 11 abstracts and short papers (extended abstracts) of presentations given at a meeting organized by the "Groupe Français du Crétacé (GFC)", held on November 27-28, 2007 at the "École des Mines" in Paris, France. These contributions are available only in English or in French. 1- Les bioévénements de la limite Albien (Vraconnien) - Cénomanien aux marges nord et sud de la Téthys (S.E. de la France et Tunisie centrale) - Bioevents at the Albian (Vraconnian) - Cenomanian boundary at the North and South margins of the Tethyan Ocean (SE France and Central Tunisia) 2- Échanges et colonisations fauniques (Ammonitina) entre Téthys et Atlantique sud au Crétacé supérieur : voies atlantiques ou sahariennes ? - Late Cretaceous faunal exchange and colonization (Ammonitina) between the Tethys and the South Atlantic: Atlantic or Saharan routes? 3- Phosphorus and trace-metal records during Cretaceous oceanic anoxic events: Example of the Early Aptian OAE in the western Tethys - Évolution de la concentration du phosphore et des métaux-traces durant les événements anoxiques du Crétacé inférieur : exemple de l'événement de l'Aptien inférieur (OAE 1a) dans la Téthys occidentale 4- L'évolution tectono-sédimentaire du système "Golfe de Gascogne-Pyrénées Occidentales" au Crétacé inférieur : un nouveau regard - The tectonic and sedimentary evolution of the Bay of Biscay-Western Pyrenees during the Early Cretaceous : a new point of view 5- The marine squamates (reptiles) from the Cenomanian-Turonian of the Tethys: a noteworthy radiation - Les squamates (reptiles) marins du Cénomanien-Turonien de la Téthys : une radiation remarquable 6- Influences boréales dans le bassin de Mons (Belgique) à l'Albien - Boreal influences in the Mons basin (Belgium) during the Albian 7- On the track of a major trans-Tethyan discontinuity - Sur la piste d'une discontinuité majeure trans-Téthys 8- The Cretaceous of Lebanon in the Middle East (Levant) context - Le Crétacé du Liban dans le cadre du Moyen-Orient (Levant) 9- Le Cénomanien-Turonien de l'Atlas saharien (Algérie) 10- Endémisme et cosmopolitisme des faunes d'ammonites de la plaque arabique au Cr&#233 ;tacé moyen (Aptien - Turonien) - Endemism vs. cosmopolitanism of the ammonite faunas from the Arabian plate during mid-Cretaceous times (Aptian – Turonian 11- La discontinuité albienne à l'échelle globale et ses implications paléobiogéographiques et biostratigraphiques - The Albian unconformity at a global scale and its palaeobiogeographic and biostratigraphic implications

Recently, representatives of the genus Cuboctostylus Bragina (order Entactinaria) were included in the Upper Cretaceous radiolarian regional stratigraphic scale of Sakhalin. The Late Cretaceous species Hexacromyum pergamenti Bragina (order Spumellaria) has morphological similarity to representatives of the genus Cuboctostylus. Peculiar features of H. pergamenti internal structure are considered. Collections of Upper Cretaceous radiolarians from southern Cyprus, Serbia, northern Turkey, Crimean Mountains, East European Platform, northwestern Kamchatka, eastern slope of the Sredinnyi Range in Kamchatka, and Shikotan Island (Lesser Kurile Range) were used for the analysis of the taxonomic composition of Late Cretaceous representatives of the genera Cuboctostylus Bragina and Hexacromyum Haeckel as well as their stratigraphic and paleobiogeographic distribution. It is established that Cuboctostylus is distributed from tropical to south boreal realms. This genus is shown to exist through almost the entire Late Cretaceous: from the middle Cenomanian to initial Maastrichtian. Hexacromyum Haeckel populated both the south boreal realm and marginal areas of the Tethys Ocean in the Late Cretaceous. The new data presented may be used for distant interregional correlations. Cuboctostylus stellatus sp. nov. and several other Cuboctostylus taxa identified in open nomenclature are described; some morphological features of Hexacromyum pergamenti are specified. [ABSTRACT FROM AUTHOR]

A representative radiolarian assemblage has been macerated for the first time from beds enriched in organic matter at the time of the Oceanic Anoxic Event (OAE-2). The assemblage includes radiolarians characteristic of the late Cenomanian, and is barren of species typical of the incipient Turonian. Consequently, deposition of beds rich in organic matter terminated in the late Cenomanian. [ABSTRACT FROM AUTHOR]

In the last decades, our knowledge of Late Cretaceous radiolarians has considerably improved. Nevertheless, there are still significant problems concerning correlation between radiolarian communities of low, temperate, and high latitudes. This work shows the possibility of using species that belong to the phylogenetic lineages of the genera Afens Riedel et Sanfilippo, 1974, and Multastrum Vishnevskaya, 1991, for biostratigraphic subdivision of the Upper Cretaceous at low and high latitudes. [ABSTRACT FROM AUTHOR]

Two new dasycladalean algae are described from the Gosau Group of the Northern Calcareous Alps in Austria. The tiny spicules of Acicularia? weisswasserensis n. sp. were found in foraminiferal wacke- to packstones associated with rudist limestones of the Weisswasser locality (Middle Coniacian), Lower Austria. The small globulous Terquemella? microsphaera n. sp. occurs in marls to marly limestones of the Pletzachalm locality (Upper Turonian), Tyrol, and Russbach locality (Upper Santonian), Lower Austria. The Terquemella- Acicularia group requires taxonomic revision; the two forms described herein, however, are clearly distinct from other species, and belong to the smallest representatives of these genera. In addition, Acicularia? aff. magnapora Kuss and morphologically similar forms interpreted as gametophores of unknown larger dasycladales are described. [ABSTRACT FROM AUTHOR]

Abstract: The La Tabla Formation is an important petroleum reservoir in the Upper Magdalena Valley of Colombia. It was deposited in regressive and lowstand systems tracts and comprises a succession of lower shoreface to coastal plain deposits. A section in the Talora Creek, near the village of Piedras, Department of Tolima, exposes 90 m of a progradational to aggradational succession composed of very fine sandstones to medium-grained pebble conglomerates, with abundant planktic and benthic foraminifers as well as bivalves and ammonites. A few well-preserved phragmocones of the ammonite Sphenodiscus pleurisepta (), collected from a level 63 m above the base of the formation, are here described and the chronostratigraphic position of the species discussed. In the Western Interior Basin of North America, S. pleurisepta ranges from the upper lower Maastrichtian Baculites clinolobatus Zone through the upper Maastrichtian Jeletzkytes nebrascensis Zone. The present findings support previous datings of the La Tabla Formation as Maastrichtian on the basis of foraminifers. [ABSTRACT FROM AUTHOR]

The work is aimed at summarizing data on Late Cretaceous radiolarians from the Crimean and West Sakhalin mountains. The Cenomanian-lower Coniacian stratigraphic interval of the Crimean Mountains yields 215 radiolarian species, and 80 concurrent species are known from the West Sakhalin Maintains. According to results of comparative analysis, there are 62 species in common from two regions, i.e., most of the species occurring in the West Sakhalin Mountains are also known from southerly regions, which is a good premise for correlation. [ABSTRACT FROM AUTHOR]

Radiolarian biostratigraphy suggested in this work for the Cenomanian-Coniacian deposits in the Crimean and West Sakhalin Mountains is enhanced to be of a higher resolution. The Cenomanian-Coniacian succession of the West Sakhalin Mountains is subdivided into nine instead of five biostratigraphic units formerly known in this region. Deposits of the Crimean Mountains are subdivided based on radiolarians within the lower Cenomanian-lower Coniacian stratigraphic interval (the original biostratigraphic chart corresponded here to the upper Cenomanian-middle Turonian interval only). The established biostratigraphic subdivisions are correlated with those of the Tethyan and Pacific scales. [ABSTRACT FROM AUTHOR]

Abstract: The Upper Cretaceous sequence (446m thick) exposed at Gebel Somar (north-central Sinai) is subdivided, from base to top, into the Raha (upper Cenomanian), Abu Qada (upper Cenomanian–lower Turonian), Buttum (middle Turonian), Wata (middle–upper Turonian), Matulla (Coniacian–Santonian), and Sudr Chalk (lower–upper Maastrichtian) Formations. Foraminifera (mainly planktonic) were used to assign ages to these. Vertical variations in the bio- and lithofacies for the Cenomanian–Santonian succession reflect global changes of sea level. During the late Santonian, the area studied was uplifted in association with the generation of the Syrian arc system. This was accompanied by non-deposition of Campanian sediments. The Maastrichtian Sudr Chalk was laid down in the basin or depocenter generated as a result of the Syrian arc system. [Copyright &y& Elsevier]

Reexamination of radiolarians from the Naiba and Bykovo formations of the Naiba reference section (West Sakhalin Mountains) is carried out. Distinguished in the section are the Cromyomma (?) nodosa-Amphipyndax sp. A (terminal early Cenomanian), Cuboctostylus kasinzovae-C. sakhalinensis (Middle Cenomanian), Cuboctostylus trifurcatus-Cassideus yoloensis (terminal middle-late Cenomanian), and Spongodiscus concentricus-Multastrum robustum (late Turonian to early Coniacian probably) assemblages. According to results of comparative analysis for North Pacific regions, concurrent radiolarian assemblages from the Naiba section and California contain up to 40% of species in common, whereas taxonomic similarity with assemblages from Japan is insignifican in contrast. [ABSTRACT FROM AUTHOR]

Abstract: In the Bavarian Alps (Germany), west of the Isar River, the abyssal deposits of the Lower Barremian to Upper Campanian Rhenodanubian Group consist of siliciclastic and calcareous turbidites alternating with hemipelagic non-calcareous mudstones. The up to 1500-m-thick succession, deposited in the Penninic Basin to the south of the European Plate, is characterized by a low mean sedimentation rate (c. 25mmkyr−1) over 60 million years. Palaeocurrents and turbidite facies distribution patterns suggest that sedimentation occurred on a weakly inclined abyssal plain. The highest sedimentation rates (up to 240mmkyr−1) were associated with the calcareous mud turbidites of the newly defined Röthenbach Subgroup, which includes the Piesenkopf, Kalkgraben and Hällritz formations (Middle Coniacian to Middle Campanian). These calcareous turbidites prograded from the west, and interfinger towards the east with red hemipelagic claystone. A high sea level presumably favoured pelagic carbonate production and accumulation on the shelves and on internal platforms in the western part of the basin, whereas siliciclastic shelves with steep slope angles have bordered the eastern part of the basin, where a dearth of turbidite sedimentation and increased Cretaceous oceanic red beds deposition occurred. In contrast to the eustatically-induced Middle Coniacian to Lower Campanian Cretaceous oceanic red beds (calcareous nannoplankton zones CC14 to CC18), red hemipelagites of Early Cenomanian age (upper part of calcareous nannoplankton zone CC9) and early Late Campanian age (upper part of zone CC21 and zone CC22) are interpreted as the result of regional tectonic activity. [Copyright &y& Elsevier]

Abstract: A major change in oceanic sedimentation from mid-Cretaceous organic carbon-enriched deep-sea deposits to predominantly Upper Cretaceous oceanic red beds (CORBs), represented mainly by deep-sea red shales and marls, occurred during the Late Cretaceous and early Tertiary in the Tethys. A variety of earth processes such as organic carbon draw-down, tectonic, palaeoceanographic, eustatic and palaeoclimatic changes, or a combination of these could cause such a change, the main significance of which is that it demonstrates that the deep ocean basins ceased to be the preferential burial site for organic carbon. A compilation of available data on CORB occurrences, composition, and age indicate that: (1) CORBs are found in a broad geographic belt extending from the Caribbean across the central North Atlantic, southern and eastern Europe to Asia; with limited occurrences in the Indian ocean; (2) both the first and the last occurrences of CORBs are diachronous; (3) CORBs are of pelagic and hemipelagic origin and were deposited in a variety of environments from continental slope to deep oceanic basin, above and below the carbonate compensation depth (CCD); (4) total organic carbon (TOC) is mostly <0.1%; haematite is relatively abundant, up to 10% in red shales; (5) the termination of CORB deposition in the Alps, Carpathians, and Himalayas was mostly a result of major tectonic events associated with intensification of continental plate migration and initial stages of collision of the Indian and Asian plates and the African and European continental plates. We suggest that changes in dissolved oxygen in the deep ocean were mainly the result of changes in the location and formation of deep water and changes in ocean circulation. It is more than probable that a score of different earth processes, including changes in climate, all acting in concert, were involved in such a major change in the deep-sea environment and location of the carbon reservoir. [Copyright &y& Elsevier]

A small section of the Perapedhi Formation in Akamas Peninsula (west of Cyprus) is comprised of umbers with intercalating layer or concretions of radiolarian cherts, which yield abundant and well-preserved Upper Cretaceous (Coniacian) radiolarian assemblage. Therefore, the previous conclusion indicating a Campanian age for the Perapedhi Formation at this locality, should be reconsidered. The age of the basal horizons of the Perapedhi Formation can vary from late Turonian to Coniacian or Santonian, an indication of the diachronous character of the lower boundary of the formation. [ABSTRACT FROM AUTHOR]

This paper aims to show the filling and stratigraphy of the units that constitute the Cambambe Basin, that is located at the mid-southern portion of the State of Mato Grosso, Brazil. The rocks of this vulcano-sedimentary unit have been deposited during Upper Cretaceous, between the Santonian and Maastrichtian Stages. The scientific literature has been associated these units to different basins, such as the Paraná Basin, the Parecis Basin and the Bauru Basin and also to other different lithostratigraphic units. Such confusion was the motivation to carry out this study in which the description and interpretation of facies associations was the main tool to clarify some of the aspects related to the Cambambe basin evolution. It has been observed five facies: Polymytic Conglomerate (PCF), Oligomitic Conglomerate (OCF), Siltstone and Mudstone (SMF), Litharenite (LF), Quartzarenite Facies (QF). This facies points to an alluvial fan system, with facies associations interpreted as corresponding to three portions: proximal, immature plains and mature plains. Such facies associations corresponds to the lithostratigrphic units that constitutes the Cambambe basin: the lower portion is the Ribeirão Boiadeiro Group, consisting of the interfingering Quilombinho and Cachoeira do Bom Jardim formations and the upper portion is the Cambambe Formation. An erosive unconfomity separates both portions. The sedimentary record exceeds 400 m in thickness and demonstrates a long-term deposition marked by numerous non-deposition surfaces, including paleosols. • Contributes to the understanding of Cretaceous stratigraphy. • Presents a proposal for the evolution of the Cambambe Basin. • Displays the distribution of facies by lithostratigraphic units. • Interprets four paleoenvironments for Cambambe Basin. [ABSTRACT FROM AUTHOR]