Search

Lithological cycles with a repetitive pattern of sandstone overlain by limestone or shale comprise the middle Minnelusa Formation in the Black Hills region, USA. At least eight lithological cycles were observed at Boulder Canyon Road (BCR), eight at Vanocker Canyon Road (VCR) and four at Hot Brook Canyon (HBC). These rocks were deposited in a nearshore to offshore marine environment, and the shale and limestone intervals at the top of these cycles yielded conodonts. Five biostratigraphically distinct Middle to Upper Pennsylvanian conodont faunas were recovered from these marine units. An upper Desmoinesian assemblage was recovered from VCR cycle 1. Two Missourian assemblages were recovered, one indicative of the Idiognathodus cancellosus Zone from VCR cycle 3 and the other indicative of the Streptognathodus gracilis Zone from VCR cycle 6. Two Virgilian assemblages were recovered, one indicative of the Heckelina simulator Zone from VCR cycle 7, VCR cycle 8 and HBC cycle 2 and the other indicative of the lower part of the "Streptognathodus" group 4 virgilicus Zone from HBC cycle 3. Two conodont biofacies were recognized within the middle Minnelusa, the low energy, offshore, Idiognathodontidae-Idioprioniodus biofacies and the higher energy, nearshore Idiognathodontidae-Hindeodus biofacies. [ABSTRACT FROM AUTHOR]

Species diff erentiation within the genus Mesorbitolina Schroeder 1962 is primarily based on the general structure of the megalospheric embryo and its biometrics. The taxonomy of three taxa, namely Mesorbitolina texana (Roemer 1849), Mesorbitolina subconcava (Leymerie 1878) and Mesorbitolina pervia (Douglass 1960) is complicated due to diff ering species concepts between authors, and, in the case of the fi rst two named, by missing type designations in the original descriptions as well as disagreements with respect to their type-localities. Herein, it is demonstrated that M. pervia is the junior synonym of Mesorbitolina birmanica (Sahni 1937) due to priority reasons, both taxa characterized by a similar-sized plano-convex protoconch. Some concepts of M. texana and M. subconcava can also be placed in M. birmanica, but not those as defi ned by lectotypes. Published data for M. birmanica suggest a late Aptian (late Gargasian) to early (? late) Albian age and a cosmopolitan distribution. Mesorbitolina texana appears slightly earlier in the late Aptian persisting into the middle Albian, and a distribution ranging from the southern USA to the Middle East. [ABSTRACT FROM AUTHOR]

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]

A biostratigraphic integration study based on the planktonic foraminifera and calcareous nannofossils from the Mango-2 well, North El Fayrouz Offshore Field, Mediterranean Sea, Egypt, provides a well-defined zonal scheme for the Oligocene-middle Miocene interval. The lithologic succession was subdivided into three formations, from oldest to youngest; Sidi Salem, Qantra and Tineh. Six planktic foraminiferal zones and four calcareous nannofossils zones, in addition to two unconformities are identified. The planktic foraminiferal zones include Ciperoella angulisuturalis, Paragloborotalia opima opima (Oligocene), Globigerinoides primordius, Praeorbulina curva (early Miocene), Praeorbulina glomerosa and Fohsella peripheroronda (middle Miocene). The calcareous nannofossil zones include Furcatolithus distentus, (Oligocene), Discoaster druggii, Helicosphaera ampliaperta (early Miocene) and Sphenolithus heteromorphus (middle Miocene). The absence of the Paragloborotalia kugleri, Paragloborotalia pseudokugleri and Furcatolithus ciperoensis zones suggests an unconformity across the Oligocene-Miocene boundary. Another unconformity was identified across the Aquitanian-Burdigalian boundary based on the absence of the Globoquadrina dehiscens, Globigerinita dissimilis, Globigerinatella insueta and Sphenolithus belemnos zones. These unconformities are most likely related to regional tectonics. [ABSTRACT FROM AUTHOR]

The deposition of a substantial amount of clastic sediments in the Krishna Godavari Basin formed a thick layer of nannofossil-rich clay known as the Godavari Clay Formation. This clayey sequence is a treasure trove for unveiling paleoclimatic and paleoceanographic information. Numerous radiometric dates from the topmost portion of this clay (top 27m) are available, covering the last 43 ka. However, the availability of data on age connotation with considerably high resolution for the deeper sediments is rare and is still awaited. In this study, we pursued nannoplankton and planktic foraminiferal investigations on the top 198 m (Hole 10D), 300 m (Hole 3B), and 198 m (Hole 5C) sediments of this basin to generate multiple age data with a relatively high resolution. First Occurrence (FO) and Last Occurrence (LO) of nannoplankton taxa Emiliania huxleyi, Helicosphaera inversa, Helicosphaera sellii, large Gephyrocapsa spp., Pseudoemiliania lacunosa, Reticulofenestra asanoi, and planktic foraminiferal taxa Globorotalia flexuosa and Globigerinella calida are considered as potential index taxa for establishing the bioevents as well as biostratigraphy.Based on these, we have identified nine events from Hole 10D, six events from Hole 3B, and seven events from Hole 5C, which are potential for assigning the relative ages.We also observed two-fold variations in sedimentation rates in all the holes and one hiatus at 110.73 mbsf in Hole 5C, indicating a shift in climate and basinal settings. Ahigh sedimentation rate of >20.59 cm/ka after ~0.4 Ma at all the holes is probably linked to the intensification of the Indian summer monsoon across the mid-Brunhes Epoch. The significantly low sedimentation rates (<14.62 cm/ka) in older sediment sequences before 0.4Ma is probably related to the relatively weak monsoonal activity. The generated age data, variations in sedimentation rates, and identified hiatus are considered to be potential for delineating paleoclimatic and paleoceanographic changes of this area since the Calabrian Stage. [ABSTRACT FROM AUTHOR]

During the Late Eocene, the West Siberian Basin became increasingly isolated from the Peri-Tethys Ocean. The final stage of thismarine connection ismarked by sediments of the Tavda Formation thatwere deposited during the Bartonian and Priabonion. We have analyzed the composition, structure and diversity of benthic foraminiferal assemblages in core material from the Kyshtyrla Quarry located in the southwest ofWestern Siberia to reconstruct the depositional environment during the terminal phase of marine sedimentation in theWest Siberian Basin (Upper Tavda Subformation). The foraminiferal record was jointly used with lithological and geochemical multi-proxy data to infer the chronology of events that shaped the critical transition until the complete closure of the basin. Based on stratigraphic indexmarkers, a Priabonian age is indicated for sediments of the Upper Tavda Subformation. From the bottom to the top of the core, the foraminiferal biotas progressively shift from shallow subtidal to low-diverse and stress-tolerant intertidal assemblages, indicative for an increasing isolation of theWest Siberian Basin. The increasing shallowing of themarine basin is accompanied by a gradual shift in grain size, and the continuous presence of benthic foraminifera and ratios of geochemical proxies (Sr/Ba, Si/Al, Ti/Al, Zr/Al, K/Al, and U/Th) indicate that mainly marine to brackish water conditions prevailed. [ABSTRACT FROM AUTHOR]

The Surgah Formation was studied in four sections (Kuh-e-Surgah anticline, Zifel, Sarkan, and Mal-e-kuh) from the NW-SE of the Zagros sedimentary basin. Forty-one planktonic foraminiferal species belonging to 20 genera were observed. The recorded species were used to subdivide the Surgah Formation into three biozones: Marginotruncana sigali-Dicarinella primitiva Zone, Dicarinella concavata Zone, and Dicarinella asymetrica Zone. Based on these data, the Surgah Formation was estimated to be of late Turonian to late Santonian age. The Coniacian/ Santonian boundary is placed at the Dicarinella asymetrica Zone. The base of the Santonian stage is identified on the FO of Globotruncana linneiana (pill box shaped), the FOs of Dicarinella asymetrica, Globotruncanita elevata and Globotruncana bulloides, and the LOs of Dicarinella primitiva, Dicarinella concavata and Muricohedbergella flandrini. [ABSTRACT FROM AUTHOR]

A rich larger foraminifera assemblage from the Eocene carbonates of the south Sabzevar region (Now-Deh section) in central Iran indicates a late Ypresian to early Lutetian age. Nine species of Alveolina d’Orbigny are studied for systematics and biostratigraphy. The assemblage includes A. minuta, A. decastroi, A. cremae, A. cremae elongata, A. decipiens ayrancensis, A. celali, A. rugosa, A. cuspidata, A. frumentiformis. We have also found nummulitids (genus Nummulites and Assilina) and orthophragmines identified as N. campesinus, N. praediscorbinus, A. placentula, A. praespira, A. reicheli, A. ex. intrec. laxispira-maior and Discocyclina archiaci bartholomei. The recovery of Alveolina cremae elongata, A. decipiens ayrancensis, A. celali, A. rugosa, A. cuspidata and Assilina praespira has permitted for the first time to extend their geographical distribution outside of the classical peri-Mediterranean area to the central Tethys regions. The obtained biostratigraphy points to the Shallow Benthic Zones SBZ11 to SBZ13, indicating the occurrence of a Lower-–Middle Eocene carbonate system. Part of the age model is supported by the calcareous nannofossil biostratigraphy that belong to the NP14b and CNE8 biozones, recorded from the central portion of the studied section. Issues regarding the application of the SBZ into the Middle East domains are discussed in terms of relative stratigraphic position and biogeographic dispersal of some significant Alveolina species. [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]

The Hadim Nappe has a relatively complete succession from the Middle(?)--Upper Devonian to Upper Cretaceous in the Taurides. The Bademli section is one of thewell exposed sections of theHadim Nappe that is selected for detailed biostratigraphic investigations. It includes a continuous Viséan stratigraphic succession. In the Bademli section, rich and diverse Early--Middle Viséan foraminiferal assemblages were recovered, most of which were reported for the first time in Turkey. Four first occurrence biozones, which approximately correspond to the Zones MFZ10 to MFZ13 of the Belgium stratotype section, are identified based on the foraminiferal analysis of the Lower-Middle Viséan strata of the Bademli section that are Ammarchaediscus-Glomodiscus first occurrence zone, Uralodiscus rotundus first occurrence zone, Pojarkovella first occurrence zone and Endothyranopsis (Reitlingeropsis) intermedia - Endothyranopsis mosquensis first occurrence zone. [ABSTRACT FROM AUTHOR]

The present study focuses on calcareous nannofossil biostratigraphy of the last 23 Myr in the Mediterranean region and is intended as a review paper in which an updated zonation is presented. This includes the improvements in biostratigraphic classification achieved in the last decades. The proposed biozonal scheme incorporates the biochronologic data derived from the integration of biostratigraphically useful events with radiometric datings, magnetostratigraphy and astronomically tuned cyclostratigraphy. This biochronology directly derives by previous compilations and includes improved data and ages derived from recent studies based on high resolution quantitative analysis of nannofossil assemblages. The presented zonal scheme consists of 21 biozones and 35 subzones spanning the last 23 Myr, named according to the well-established code-system MNN (Mediterranean Nannofossil Neogene) for the Miocene and Pliocene time interval and MNQ (Mediterranean Nannofossil Quaternary) for the Pleistocene and Holocene. In addition, a revision of the nannofossil biostratigraphy at the Oligocene/Miocene transition is given, with the introduction of Zone MNP26 (Mediterranean Nannofossil Paleogene), as a result of the different age assigned to the Oligocene/Miocene chronostratigraphic boundary. This zonation provides a significant bio-chronostratigraphic resolution of about 0.5 Myr, corresponding to a degree of precision functional for dating sedimentary successions and, therefore, useful for geological studies (e.g. geological mapping, temporal scanning of geological phasis). The biostratigraphic resolution can be furtherly improved through integration with the analogous scheme recently established for planktonic foraminifers. [ABSTRACT FROM AUTHOR]

Three key Paleocene deep-sea sections cropping out in northern Italy contain intercalations of calciturbiditic, larger foraminifera-bearing beds derived from shallow water environments. The reconstructed Southern Alps record obtained by splicing the three sections allowed a direct correlation of the shallow benthic SB and calcareous nannofossils CN Zones, leading new data about the Shallow Benthic biozonation for the Danian-Thanetian interval and proposing four new SBP (Shallow Benthic Paleocene) Zones (SBP1-4). Such revision relies on an innovative biostratigraphic approach based on larger foraminiferal biohorizons instead of marker species according to the traditional approach used since the introduction of the SB Zones. Based on our study, the SBP1/SBP2 boundary turns out to be about 2 Ma after the K/Pg crisis, highlighting a quite fast recovery of the complexity among foraminifera. [ABSTRACT FROM AUTHOR]

Here, we revise and update the biostratigraphy of larger foraminiferal assemblages in three sections of the Priabonian Sanetsch Formation in the Helvetic Nappes of theWestern Swiss Alps: The Sex Rouge (SE) and the Sanetsch Buvette (SA) sections in the Wildhorn Nappe Complex, and the Col des Essets (ETS) section in the most external Morcles Nappe. In the SE and SA sections, the Tsanfleuron and most of the Pierredar Limestone members of the formation are assigned to SBZ 19 (early Priabonian), while the uppermost part of the formation is assigned to SBZ 20 (late Priabonian). In the external ETS section the entire Sanetsch Formation contains assemblages characteristic of SBZ 19, suggesting an earlier, middle-late Priabonian onset of the hemipelagic Stad Formation (“Globigerina Marls”). Since it was established in 1998, the Shallow Benthic Zones (SBZ), a biozonation based on larger foraminifera, has been a useful tool in the biostratigraphy of the Paleogene. Biozonation proposals for the late middle-late Eocene are based mainly in biometrical subdivision of lineages of nummulitids and orthophragmines, which requires measurements in oriented sections of isolated specimens. Here, we define previously unreported taxa from the Sanetsch Formation, which are considered characteristic for the Priabonian. They are easy to identify in random sections and thus useful biostratigraphical markers. We also describe a new orthophragminid genus, Virgasterocylina n. gen. (Orbitoclypeidae) characterized by the presence of rods, radial thickenings of calcite along ribs; a new species of Rotorbinella, R. epardi n. sp., and a new genus and new species of difficult suprageneric attribution, Sanetschella indeprensa n. gen., n. sp. We add the new taxa to the larger foraminiferal association characterizing the Priabonian (SBZ 19–20). The revision of the literature, together with our own sample collections revealed that these new taxa occur in Priabonian rocks from different basins in the western Tethys. Virgasterocylina n. gen. also occurs in the Caribbean bioprovince in the middle and upper Eocene. In the western Tethys, Virgasterocylina ferrandezi is subdivided into two subspecies, V. f. ferrandezi (Özcan and Less) and V. f. lessi n. ssp., which characterize the SBZ 19 and 20 biozones respectively. [ABSTRACT FROM AUTHOR]

Eocene larger benthic foraminifera including orthophragmines, nummulitids and alveolinids from the Jahrum and Pabdeh formations in the Zagros region are presented. The studied 20-m-thick stratigraphic interval contains, Asterocyclina Gümbel 1870, Nemkovella Less 1987, Orbitoclypeus Silvestri 1907, Discocyclina Gümbel 1870, Nummulites Lamarck 1801, Assilina d’Orbigny 1826 and Alveolina d’Orbigny 1826. This larger benthic foraminiferal assemblage testifies for the shallow benthic zones (SBZs) 15 to 17, which ranges from the middle Lutetian up to the early Bartonian. Further micropaleontological analysis made on intercalated planktonic-rich levels helps calibrate the larger foraminifera biostratigraphy, demonstrating a correlation with the E11 biozone. This confirms that the chronostratigraphic calibration of the SBZs made by previous authors for the peri-Mediterranean area can, through the middle Lutetian to the early Bartonian, be applicable in the Middle East as well [ABSTRACT FROM AUTHOR]

Abiometrical study on four reticulate Nummulites populations from the lower part of Asmari Formation of the Vazag section (Zagros zone) is carried out. The biostratigraphy obtained by studing the succession points to the Early Oligocene (Rupelian), indicating shallow benthic zones SBZ21 and SBZ22A by the occurrence of Operculina cf. complanata, Eulepidina formosoides, Nephrolepidina sp. The age assignment is calibrated with calcareous nannofossils biostratigraphy indicating the NP22–NP23 (=CNO2–CNO3) Zones. We have observed a stratigraphic trend related to Nummulites bormidiensis Tellini 1888 that results to be characterized by two populations composed of transitional Nummulites fichteli/bormidiensis with values of mean inner proloculus that exceeds by very little the boundary commonly established at 300 µm. Such a populations, indicated as Nummulites ex interc. bormidiensis et fichteli, span through the lower Rupelian where classically just N. fichteli is reported so far. The stratigraphic distribution ofNummulites bormidiensisis and related transitional forms is here stretched to the Rupelian (SBZ21 and SBZ22A), encompassing older ages than previously recorded throughout the Neo-Tethys Ocean. [ABSTRACT FROM AUTHOR]

Paleogene sedimentary deposits are exposed in several localities along the extended Thrace Basin in the Greek territory. One of the best sites in terms of preservation, richness and type of sediment occurs along the coastline of Fanari village (SW of Komotini city). Two outcrops, which consist of upper Eocene shallow marine clastic sediments, were sampled to analyze the full spectrum of larger benthic foraminifera (LBF) that comprises a rich and diverse assemblage of orthophragmines (Discocyclina, Orbitoclypeus and Asterocyclina), nummulitids (Nummulites, Assilina, Operculina, Heterostegina and Spiroclypeus), and other benthic taxa (e.g., Silvestriella, Pellatispira, Fabiania, Sphaerogypsina, etc.). Adetailed systematic description of LBF from Fanari is presented, which refines the biostratigraphic age of SBZ (Shallow Benthic Zone) 20 corresponding to the late Priabonian for the whole sequence. Twenty-four taxa among which six at (chrono)subspecies level belonging to twelve genera were identified and morphometrically analyzed for the first time from Greece. The LBF assemblage is characterized by the constant presence of Nummulites fabianii almost throughout the whole sequence. The most abundant species are Pellatispira madaraszi and Spiroclypeus carpaticus, though they occur in the upper part of the sequence along with orthophragmines. The foraminiferal distribution in the sequence enables paleoenvironmental observations and the reconstruction of the evolution of the Fanari area. Three main depositional marine shelf facies are distinguished at the shallow upper foreslope of the carbonate platform, making the Fanari section a key area not only of latest Priabonian but also of outer shelf biofacies. [ABSTRACT FROM AUTHOR]

Arelatively diverse assemblage of larger benthic foraminifera from the Asmari Formation is described based on the recovered samples from two subsurface sections, offshore and onshore, southern Iran. Due to its position in the Tethyan Seaway between the Mediterranean and Indo-Pacific, the Zagros belt as a part of the Middle East has high significance in palaeobiogeography. The fauna is dominated by both hyaline perforated and porcelaneous forms. Eight species of larger benthic foraminifera are described, including Nummulites fichteli, N. vascus, Operculina complanata, Archaias operculiniformis, Praerhapydionina delicata, Austrotrillina striata, Peneroplis thomasi, and P. evolutus. The presence of N. fichteli and N. vascus in the absence of lepidocyclinids indicates the SBZ 21 Zone referring to a short time span restricted to early Rupelian. [ABSTRACT FROM AUTHOR]

Quantitative palynofloral analysis ofHauterivian and early Barremian aged sediments at Speeton (northeast England) and in the UKCS,Witch Ground Graben has involved 39 outcrop samples and over 1000 samples from 40 wells in the Northern Area Claymore (NAC), Scapa and Highlander fields, including extensive conventional core. Very close sampling, particularly within the early Hauterivian at Speeton, has allowed dinocyst events to be tied closely to ammonite zones and their extrapolation offshore. The timing of deposition of the Scapa Sandstone Member of the Valhall Formation is discussed for Scapa Field, and a transect across the field is presented. Individual Scapa sedimentary units have been assigned to particular ammonite zones and the timing of paleoenvironmental changes at Speeton assessed in relation to them. The zonation scheme proposed by Duxbury (2001) has been re-visited, further refined and some boundaries adjusted, particularly in relation to ammonite zone equivalence. Eighty-five key palynofloral events have now been recognised in the Hauterivian and early Barremian, including many first occurrences. Thirty-seven new species and seven new subspecies of stratigraphically significant dinoflagellate cysts are described, four new combinations have been effected and the status of one taxon has been raised from subspecies to species rank. The diagnoses of one genus and one species have been emended. [ABSTRACT FROM AUTHOR]

The Cretaceous Farrokhi Formation is located in theKhur area of central Iran and yielded a reasonablywell-preserved rich planktonic foraminiferal assemblage. This formation consists of 154mof fossiliferous marl and limestone. The lower and upper bounding surfaces of the Farrokhi Formation are unconformable with the underlying Haftoman Formation and the overlying Chupanan Formation. In this research, 46 planktonic foraminiferal species belonging to 19 genera were identified and resulted in recognition of the following three biozones (from base to top); the Globotruncana aegyptiaca Interval Zone (IZ), the Gansserina gansseri IZ, and the Contusotruncana contusa IZ. This biozonal framework places deposition of the Farrokhi Formation during the late Campanian to early Maastrichtian. Biostratigraphic comparison between the samples for this research and data from three other studied sections within the Farrokhi Formation indicates that the basal and upper boundaries of the formation are time-transgressive and migrate chronologically from north to southeast. Since the first occurrences of Pseudoguembelina palpebra and Rugoglobigerina pennyi mark the latest Campanian worldwide, we approximate the Campanian/Maastrichtian boundary based on the FOs of Trinitella scotti and Rugoglobigerina hexacamerata, and identify the basal Maastrichtian by the last occurrence of Laeviella bollii. [ABSTRACT FROM AUTHOR]

Quantitative analysis of the lowerMiocene of Ocean Drilling Program Hole 959A from theWest African margin was performed to document all the calcareous nannofossil biostratigraphic events present. Combinedwith data from previous investigations of the lowerMiocene from the tropicalAtlantic, this research identifies and tests the viability of markers used in current zonation schemes, recognizes alternative markers for age boundaries, and examines statistically the most probable order of events in the lower Miocene using the Ranking and Scaling method (RASC). In Hole 959A, all major zonal and subzonal boundaries from CN1 to CN4 were identified, except for the boundary between Subzones CN1a and CN1b, using primary and secondary markers from the Okada and Bukry (1980) zonation. In addition, all age boundaries from the Chattian to Langhian stages were recognized or closely estimated using the calcareous nannoplankton markers. The resultant list of events extracted from Hole 959Aalong with events from other seven sites were examined biostratigraphically using RASC. A well threshold of four was selected as an appropriate control parameter, resulting in 22 events in the optimum sequence, 13 of which had a low standard deviation. Furthermore, interpolation of ages of events using Age/Depth model for Hole 959A was examined. The extracted ages provided a reasonable preliminary age estimate for the secondary events. [ABSTRACT FROM AUTHOR]

Late Albian -- early Cenomanian calcareous nannofossil assemblages from five mid-latitude localities (23-35°) were analyzed using probabilistic and deterministic methods to produce comprehensive and quantitative biostratigraphic sequences that were compared to the widely used 'CC' and 'UC' calcareous nannofossil zonation schemes. This was done to examine their fidelity and general applicability for mid-latitude biostratigraphy and determine whether these quantitative methods can increase the resolution of said schemes. Four biozones spanning the upper Albian through middle Cenomanian were determined using unitary associations (UAs) and ranking and scaling (RASC) optimumsequence from which last appearance datum (LAD) of -- Gartnerago stenostaurion, first appearance datum (FAD) -- Lithraphidites eccentricus, and LAD -- Staurolithites mutterlosei were determined to be reliable early Cenomanian markers at mid-latitudes, while the FAD and LAD of Calculites anfractus are unreliable bioevents and should not be used as a secondary marker for the Albian -- Cenomanian boundary. In addition, we have revised the stratigraphic position of the FAD of L. eccentricus, which was previously assigned to the middle-Cenomanian. The proposed FAD was shortly after the Albian -- Cenomanian boundary, before the FAD of Corollithion kennedyi. We conclude that UAs are more robust than RASC bioevents for this time sequence; however, both methods do not account for the asynchronicity of depositional and biotic chances. Despite these caveats, combining the results for both methods has proven to be a powerful quantitative biostratigraphic tool. [ABSTRACT FROM AUTHOR]

The upper Albian exposed near the Imbrication Zone of northern Tunisia is composed of a pelagic sequence that includes organic-rich beds. High-resolution biostratigraphy based on planktic foraminiferal bioevents across marker beds (i.e., organic-rich beds), allows revision of the lithostratigraphic subdivision and zonal scheme in comparison with late Albian time equivalents recorded in the northern Tethyan margins. In the present study, we proposed a new subdivision of the upper Albian lithostratigraphic section that now includes the Mellegue horizon as an equivalent of theAmadeus Segment rhythmic marl/limestone interval (central Italy). Three studied sections are subdivided into five biozones with the abundance and morphological trends of planktic foraminifera and inferred paleoenvironments: 1) The Biticinella breggiensis Total Range Zone is characterized by the appearance of ticinellids with pinched chambers (i,e., Ticinella praeticinensis) and is recorded a few meters above the first occurrence of Biticinella breggiensis. Agradual increase of trochospiral thick-walled (B. breggiensis, T. roberti, T. raynaudi) and Globigerinelloides taxa, reflecting mesotrophic conditions. 2) The Pseudothalmanninella subticinensis Interval Zone includes the first appearance of keeled forms (Ps.subticinensis), associated with abundant ticinellids with flattened chambers (B.breggiensis, T. roberti) below the base of the organic-rich Mellegue horizon, indicating an oligotrophic environment. 3) The Pseudothalmanninella ticinensis Interval Zone. The continuous occurrence of T.primula and the scarcity of Globigerinelloides throughout the lower part of this zone indicates an oligotrophic to weakly mesotrophic environment. The occurrences of radiolarian-rich horizons and abundant forms with elongated chambers (T. raynaudi) in the lower part of this zone indicate an abrupt shift to enhanced eutrophic and dysaerobic conditions. 4) The Thalmanninella appenninica Zone, which shows a decrease in abundance preceding the extinction of ticinellids, and a gradually increasing number of specialized keeled forms (i.e., Th. appenninica), indicates oligotrophic conditions. 5) The Planomalina buxtorfi Total Range Zone is characterized in its lower part by an increasing abundance of clavate forms with radially elongated chambers (i.e., Clavihedbergella) above the organic-rich bed of the MouelhaMember, indicating low-oxygen, oligotrophic to mesotrophic conditions. [ABSTRACT FROM AUTHOR]

A new ostracod fauna was recovered and described from the Paleogene Claron Formation, famous worldwide for the "pink cliffs" of Bryce Canyon National Park and Cedar Breaks NationalMonument, in Utah, USA. The ostracods are from a section located along Sweetwater Creek in Garfield County that also contains gastropods, ichnofossils, algal impressions, charophytes and vertebrates. This diverse, freshwater lacustrine ostracod fauna contains the following 12 species: Paracandona rosaepraeceps n. sp., Candona artesensis, Cyclocypris (Laevicypris) eaglespringsensis, Cyclocypris (Leucocypris) trapezoidalis, Cypris pagei, Scottia subquadrata, Timiriasevia changzhouensis, Heterocypris whiteriverensis Cypris sp. 1, Djungarica sp. 1, Gen. aff. Bisulcocypridea sp. 1 and Pseudocandona sp. 1. The presence of a mixed assemblage of strictly early Eocene ostracod species and others with a wider stratigraphic distribution suggests that the base of the Sweetwater Creek section might extend into the Paleocene, which agrees with previous observation of Paleocene charophyte taxa in basal strata of the Sweetwater Creek section. [ABSTRACT FROM AUTHOR]

Adetailed study on radiolarian biostratigraphy and paleoecology has been carried out from three outcrops on Havelock Island, belonging to theRitchie'sArchipelago of Andaman and NicobarGroup of islands. Though most of the radiolarian taxa aremoderately preserved, it was possible to demarcate an age ranging from late early to early middleMiocene based on index radiolarians of RN4 andRN5 zones. An attempt has been made to correlate the radiolarian events recorded hereinwith earlier reports on radiolarians from differentDSDP, ODP, and IODPsites of the Indian Ocean and the onshore sections of different islands of theAndaman and NicobarBasin.A total of 119 radiolarian taxa belonging to 70 genera have been recorded in the present study, out of which 4 species are being reported for the first time from the northeastern part of the Indian Ocean. Diversity analyses were performed to deduce the Shannon Diversity Index, Simpson Index, Margalef Richness, and Pielou's Evenness. TheWater Depth Ecology index (WADE) has been analyzed for a better understanding of the paleoecological perspectives, and the Nassellaria-Spumellaria ratio of each outcrop has been calculated to ascertain the water depth. Comparison of the data obtained from diversity analysis andWADE index provides a clear picture of the environment during the late early to early middleMiocene. The overwhelming dominance of warm species of radiolarians may be linked to the Miocene Climate Optimum (MCO) event. [ABSTRACT FROM AUTHOR]

The Abderaz Formation was analyzed from four stratigraphic sections (Qaleh-Zo, Abderaz village, Mozduran pass (type section of the formation), and Chahchahe) in awest to east transect of theKopeh-Dagh Basin. TheAbderaz Formation is composed of light gray shale and marl alternated with limestone rich in echinoids and inoceramids. Planktonic foraminifera were studied in detail in order to determine the Turonian-Coniacian boundary with more accuracy and to highlight bio-events around this boundary in theKopeh-Dagh sedimentary basin. Nineteen planktonic foraminifera species belonging to 12 genera were identified in the Turonian-Coniacian transition interval. Four planktonic foraminifera biozones are recognized in all studied sections; they are 1) Whiteinella archaeocretacea PartialRange Zone, 2) Helvetoglobotruncana helvetica Total Range Zone, 3) Marginotruncana sigali-Dicarinella primitiva Partial Range Zone, and 4) Dicarinella concavata Interval Zone. In all studied sections, the Turonian-Coniacian boundary is placed at the base of the Dicarinella concavata Interval Zone. As in our previous work, we confirm that the base of the Coniacian stage in the Kopeh-Dagh sedimentary basin is distinguished based on the first occurrences of Dicarinella concavata, Pseudotextularia nuttalli, and Contusotruncana fornicata, and on the last occurrences of Dicarinella imbricata, Marginotruncana paraconcavata and Marginotruncana schneegansi. [ABSTRACT FROM AUTHOR]

We propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral planktonic foraminiferal species that have traditionally been included in Globigerinelloides. The revised taxonomy is necessary because of a ~6 m.y. gap between the extinction of planispiral species during the late Aptian and the next younger occurrence of planispiral species in the middle Albian. Our stratophenetic taxonomic groupings utilize ontogenetic morphometric data, shell wall ultrastructure, and general morphologic features observed from Scanning Electron Microscope and X-radiograph images of primary type specimens and globally distributed hypotype specimens. The planispiral lineage Laeviella n. gen., whose type species is La. bentonensis (Morrow), first appeared in the middle Albian and is postulated to have evolved from the evolutionary series Ticinella primula Luterbacher-Laviella primuloides n. sp. Laeviella is characterized as having a smooth to finely pustulose wall texture and a moderate chamber size increase rate. Two additional species, La. tururensis (Brönnimann) and La. bollii (Pessagno), are included in Laeviella with the youngest species of the genus, La. bollii, becoming extinct during the late Campanian. Planohedbergella, with Plh. aspera (Ehrenberg) as its type species, is revised to include 10 species that show a wide variation in chamber arrangement, wall microstructure and test morphology, but all have a moderately to coarsely pustulose wall texture on some or most final whorl chambers. Its stratigraphic range is from the late Albian-Cretaceous/Paleogene boundary. The oldest species is Plh. ultramicra (Subbotina), which evolved from Planomalina pulchella Todd and Low during the late Albian. Planohedbergella circularis n. sp. is described as a new late Campanian-Maastrichtian species representing forms with evolute coiling, a large number of final whorl chambers, and a slow chamber size increase rate. Polycamerella n. gen. is described as a monospecific genus, with Po. tardata n. sp. as the type species. It is a small, biapertural form with a very slow chamber expansion rate and a stratigraphic range from the late Campanian-Maastrichtian. The ancestor of Po. tardata, is tentatively identified as Plh. ultramicra. [ABSTRACT FROM AUTHOR]

The carbonate-dominated Upper Cretaceous Ilam Formation is representative of an important reservoir in the Zagros Basin. In this study, planktonic foraminiferal biostratigraphy of the Ilam Formation was investigated in the Kuh-e-Surgah section in western Iran. In the studied section, the 170 m thick Ilam Formation ismainly composed of limestoneswith shale intercalations. The formation conformably overlies and underlies the Surgah and Gurpi formations, respectively. Twelve genera and 24 species of planktonic foraminifera were identified. The following planktonic foraminiferal biozones were identified: the Dicarinella asymetrica Total Range Zone (latest Coniacian--late Santonian), the Globotruncanita elevata Partial Range Zone (Santonian to early Campanian), the Globotruncana ventricosa Interval Zone (middle to late Campanian.), the Radotruncana calcarata Total Range Zone (late Campanian.), the Globotruncanella havanensis Partial Range Zone (late Campanian) and the Globotruncana aegyptiaca Interval Zone (late to latest Campanian). In general, the biozones show that the Ilam Formation in the studied section is latest Coniacian--late Campanian in age. The Santonian--Campanian boundary in theKuh-e-Surgah section correlateswith the Globotruncanita elevata Partial Range Zone. The recognized biozones in the Ilam Formation are comparable with those recorded in other parts of the Tethyan Realm. The crinoid species Marsupites testudinarius is absent in the studied section. Generally, the last occurrence of this cosmopolitan species indicates the base of the Campanian stage. The Santonian/Campanian boundary was placed in the lower part of the Globotruncanita elevata Partial Range Zone at the base of the Ilam Formation in the studied section. [ABSTRACT FROM AUTHOR]

The present study has been carried out from the NGHP sediment core (NGHP-01-17A) of northeast Indian Ocean on different siliceous microfossils represented by diatoms and radiolarians along with calcareous nannofossils. Samples from the bottommost subunit Ic of the sediment core (684.09 mbsf to 369.62 mbsf) have been analysed. This contribution is the first comprehensive account on the Tortonian diatom assemblages from the offshore of northeast Indian Ocean that has been integrated with the radiolarian zonations. For determining the relative age of the sequence more precisely the obtained dataset also have been correlated to the calcareous nannofossil zones and eventually an attempt has been made to establish an integrated biostratigraphy. Detailed taxonomic analysis of the diatoms reveals the presence of 118 diatom taxa belonging to 49 genera. Three diatom biozones have been determined using CONISS cluster analysis. Based on the index radiolarian taxa in the studied samples, the entire sequence is assignable to RN6, RN7 and RN8 zones. The samples also contain stratigraphic marker taxa of calcareous nannofossils that allow identifying NN9, NN10 and NN11 zones corresponding to CNM13 – CNM16 zones. The ages of the bottommost and topmost sample of the analysed section of the core have been estimated < 10.49 Ma and > 7.39 Ma respectively. To estimate the sedimentation rate an age-depth model has been proposed using diatom, radiolarian and calcareous nannofossil events. All the microfossil assemblages of the present study have been correlated with the known assemblages of late Miocene, specifically Tortonian from DSDP, ODP, IODP expeditions and onshore sediments of Indian Ocean as well as equatorial Pacific Ocean. Diversity analysis has been carried out to quantitatively estimate the diversity and dominance of the diatom taxa. Planktic/benthic ratio of the diatoms has been calculated to evaluate the water depth. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous stratigraphic succession in the western part of the Valles–San Luis Potosí Platform (central to eastern Mexico) reflect the interaction between various paleo-oceanographic factors including sea–level change, tectonic factors, and the type and supply of sediments. The El Abra Formation is a shallow–water carbonate deposit that is overlain by the hemipelagic–pelagic Soyatal Formation, which represents the transition to a deeper, eutrophic, open marine environment in the latest Cenomanian–earliest Turonian (Whiteinella archaeocretacea Partial Range Zone). This unit is linked to a sea-level rise that occurred on a global scale and flooded the platform, coinciding with the Oceanic Anoxic Event 2 (OAE 2). This change is well–marked by faunal assemblages with a low diversity, and environmental stress–resistant species as well as values of δ13C excursion, total organic carbon (TOC) and trace element signatures. These data suggest that in this time the ocean was oxygen deficient. During the early Turonian the platform was completely drowned, which led to re-establishment of the oligotrophic environment. These conditions favored for development of the planktonic foraminifera of the Helvetoglobotruncana helvetica Total Range Zone with the occurrence of keeled forms (k/strategists) even continuing as far as the late Santonian thus in the Soyatal interval two biostratigraphic zones are also recognized: the Dicarinella concavata Interval Zone (late Turonian–late Coniacian) and Dicarinella asymetrica Total Range Zone (early–late Santonian). This indicates that the studied part of the Valles–San Luis Potosi Platform remained flooded during this time, in contrast with Mediterranean Tethys regions where recovery of the shallow-water carbonate platforms occurred in the latest Turonian to mid–Coniacian. The planktonic foraminiferal assemblages of this interval are diverse, composed of large and complex keeled morphotypes, which indicate an open deep–sea environment. [ABSTRACT FROM AUTHOR]

Astratigraphical challenge has long been associated with the debatable K/Pg boundary-transition in Iraq, particularly in the high folded zone of the western Zagros fold-thrust belt (Kurdistan Region). However, dissensions regarding the boundary have remained controversial. Because of differing interpretations most of the previous studies considered it as a hiatus and/or erosional surface. Here, we present a high-resolution investigation of the planktonic foraminiferal biostratigraphy across the K/Pg boundary from three sections (Per Fat, Xezava, and Behere) within the Dohuk and Zakho areas of the Kurdistan Region of Iraq. The contact zone shows a lithostratigraphic resemblance and is represented by the upper part of the Shiranish Formation (late Maastrichtian) with the overlying Aaliji Formation (Danian), positioned in a continuous pelagic marlstone that exhibits a change in color from pale blue of the Cretaceous (Shiranish Formation) to light brown at the base of the Paleogene (Aaliji Formation). The biostratigraphic investigations across the studied interval reveal threeUpperCretaceous zones: Pseudoguembelina hariaensis p.p. (CF3) Interval Zone, Pseudoguembelina palpebra (CF2) Interval Zone, and Plummerita hantkeninoides (CF1) Total Range Zone. Four main zones and three subzones of the Danian are recorded: Guembelitria cretacea (P0) PartialRange Zone, Parvularugoglobigerina eugubina (P-) Total Range Zone, Parasubbotina pseudobulloides (P1) Partial Range Zone (Globoanomalina archaeocompressa (P1a) Partial Range Subzone, Subbotina triloculinoides (P1b) Interval Subzone, Globanomalina compressa - Praemurica inconstans (P1c) Interval Subzone, and Praemurica uncinata p.p. (P2) Interval Zone. High biostratigraphic resolution indicates a completeK/Pg transitionwith no hiatus at the three studied localities in the Dohuk and Zakho areas. [ABSTRACT FROM AUTHOR]

Septfontainella (type-species S. carpatobalcanica n. sp.), a new genus of larger benthic foraminifera (familyHauraniidae, subfamily Amijiellinae) is described from the upper Berriasian of the Carpatho-Balkanides, eastern Serbia and Romania (Southern Capathians), both part of the Getic domain. It is characterized by large elongate dimorphic tests with a reduced coiled stage and a rectilinear-uniserial adult partwith chambers displaying a coarse and irregular subepidermal network. Triangular-shaped first order radial partitions extend into the chamber lumen attaching to the succeeding septum. Septfontainella gen. nov. is compared with the Lower Jurassic Cymbriaella Fugagnoli and the Lower Cretaceous Bramkampella Redmond. Septfontainella n. gen. further substantiates the occurrence of a Berriasian origination event of larger benthic foraminifera in inner carbonate platform facies of the Neotethysian realm. [ABSTRACT FROM AUTHOR]

This study presents results of integrated larger foraminiferal biostratigraphy, lithofacies and stable carbon isotope (S13Corg) analysis carried out in the Sylhet Limestone of Dillai Parbat Limestone Mine succession, Karbi Anglong District, Assam. Larger foraminiferal assemblages assign a middle Eocene age to the studied succession of Sylhet Limestone. The Shallow Benthic Zone (SBZ) 13 and SBZ 16-18 and abarren interval in between is recognized in the studied part of the Sylhet Limestone. The SBZ 13 Zone (early Lutetian) is represented by fossiliferous limestone at the base of the section and is inferred to have been deposited in a subtidal environment. The overlying barren interval lies in the arenaceous interval and was likely deposited in a subtidal channel sand shoaling bars. The upper part of the section is marked by SBZ 16-18 (late Lutetian to Bartonian) and was deposited in subtidal channel sand inner neritic zone environments, followed by intertidal marl to subtidal limestone. The organic carbon stable isotopic data reveals a sharp negative excursion at about 34-35 m of the succession, which may be correlated with Middle Eocene Climatic Optimum (MECO) and/or vegetation types. This and earlier studies from India and elsewhere indicate that during the middle Eocene, the Neo-Tethys Sea was open and connected through the East and West coasts of India, Northeast India, western Himalaya, and most of the Middle East and southeast Europe. This vast area produced enormous amount of petroleum. [ABSTRACT FROM AUTHOR]

Oxygen isotope stratigraphy and calcareous nannofossil biostratigraphy in the upper part of the Kiwada Formation, which is part of theKazusa Group in the Boso Peninsula in the central part of the Pacific coast of Japan, were examined to establish a high-resolution age model and estimate the age of the lower part of Pleistocene nannofossil biohorizons in the northwestern Pacific region. The new age model indicates that the upper part of the Kiwada Formation corresponds to Marine Isotope Stage (MIS) 41 through MIS 36. Two nannofossil biohorizons, the last occurrences of large forms of Gephyrocapsa (>5.5 µm) and Helicosphaera sellii, were recorded in the examined section. The LOof large Gephyrocapsa spp. coincideswith theMIS 37/38 boundary which is 1241.2 ± 0.4 ka. The LOofH. sellii is located in late MIS 40 and has a calculated age of 1291.4 ± 1.4 ka. These biohorizons are traceable even though the LO of H. sellii is a diachronous event. Size variations of Gephyrocapsa from approximately 1250 ka are discussed and fluctuations of small size Gephyrocapsa could represent cyclic changes of the Kuroshio and Oyashio currents. [ABSTRACT FROM AUTHOR]

The Kurdistan region of northern Iraq contains world-class outcrops that make it possible to examine the Cretaceous deep and shallow marine Tethyan faunal succession. Six separate sections covering the Shiranish, Bekhme, Mergi and Qamchuqa formations have been investigated in this study from the Shiranish Islam area. A number of papers have been published on this area, but no comprehensive biostratigraphic record has been published that fully documents the Cretaceous stratigraphy and the chronostratigraphic interpretation of the succession. As a result, this has led to significant lithostratigraphic and chronostratigraphic uncertainties. The upper part of the Qamchuqa is pervasively dolomitized. Rare occurrences of foraminifera are found in less dolomitized intervals in thin-section indicating an early - middle Albian age for the top of the formation. A thin interval comprising the Gir Bir Formation is Cenomanian in age and is present between the top of the Qamchuqa Formation and the overlying conglomerate. Historical studies indicate that the Turonian Mergi Formation occurs between the Qamchuqa and Bekhme formations, but our field and analytical data does not support it as a discrete lithostratigraphic entity, as Turonian aged faunas were not recognized. The conglomerate separating the top of the Gir Bir and base of the Bekhme is subdivided into three units (A, B & C). Units Aand B are late Cenomanian to early Turonian age, whilst Unit C is of Campanian age. Asignificant hiatus separates the Gir Bir and the Bekhme, which encompasses the intra Turonian to Santonian. The limestone facies of the lower part of the Bekhme Formation contains rich benthic foraminiferal faunas (miliolids, Pseudedomia, Cuneolina) of early - early middle Campanian age. This lower - lower middle Campanian section at Shiranish Islam is considered to be equivalent of the upper part of the Sa'di Formation in central Iraq and is therefore re-assigned on the basis of chronostratigraphic attribution to the Sa'di (equivalent) herein. The top of the early - early middle Campanian biofacies is abruptly truncated by an omission surface, marked by an erosive base, an influx of clastic material and a major up-section biofacies change characterized by an influx of Pseudosiderolites and Orbitoides representing an intra-Campanian hiatus. The bioevent sequence suggests that this hiatus at Shiranish Islam comprises at least the middle Campanian (upper part of the G. elevata Zone) into the late Campanian (intra R. calcarata Zone), from approximately 80.64 Ma to 76.09 Ma with 4.55 my missing. The middle part of the Bekhme Formation comprising the Pseudosiderolites - Orbitoides facies is thin (c. three meters) and is re-assigned to the Lower Bekhme Member. The boundary between the Lower Bekhme Member and the Upper Bekhme Member is conformable and marked by a gradual up-section reduction in the size and presence of larger benthic foraminifera (Orbitoides, Pseudosiderolites) and an increase in the planktic component (small planktics and calcispheres). This trend of gradually increasing water depth continues into the Shiranish Formation, with no apparent major breaks in deposition. The Campanian - Maastrichtian boundary falls within Unit A of the Shiranish Formation. Deposition of the Shiranish continued into the earliest late Maastrichtian and is unconformably overlain by the Danian Kolosh Formation. The hiatus between the top of the Cretaceous and the Paleocene extends from the early late Maastrichtian (c. 68.86 Ma) to the upper part of the Danian (62.2 Ma) with an estimated duration of 6.66 my. [ABSTRACT FROM AUTHOR]

The peak "hothouse" interval of the Turonian-Coniacian (93-87 Ma) is represented on the U.S. middle Atlantic Coastal Plain by sequences of the Raritan/Bass River, Magothy, and Cheesequake Formations deposited on a passive continentalmargin as mixed wave-, tide-, and river dominated deltas. We apply sequence stratigraphy integratedwith biostratigraphy to identify and map two major sequence boundaries separating the Raritan/Bass River, Magothy, and Cheesequake Formations and four to five (Mg1, Mg2, Mg3, Mg4, Mg5) Magothy sequences using continuous cores, outcrops, and geophysical logs in New Jersey. We extend correlations into New York and Delaware using well logs. The Magothy sequences disconformably overlie the well-dated (>93 Ma) lower Turonian to Cenomanian marine Raritan/Bass River sequences and are disconformably overlain by the marine Cheesequake Formation, which straddles the Coniacian/Santonian boundary. A "mid-Turonian" hiatus (ca. 93-90 Ma) associated with this major disconformity is a global sequence boundary (K-Tu4) reflecting a ~25 m sea-level lowering based on published NJ and Russian Platform backstripping records that indicate this was a major lowering of GlobalMean Sea Level (GMSL). Higher-order (~1 Myr scale) sequence boundaries bracketingMg1-Mg5 apparently correlate with global sequences but are only associated with low-amplitude (<25 m) sea-level falls. Mapping of sequences within the Magothy Formation shows the influence of 2 to 3 moderate-sized river sources, with thickening northeastward toward Long Island, New York, and thinning southwestward toward Delaware. Thick northern depocenters contrast with the preceding Potomac Formation (Barremian-early Cenomanian) with thick southern depocenters. This seesawing of basins on the 100-300 km and 2-10+ Myr scales is due to tectonism likely from changes inmantle dynamic topography. The remarkably widespread distribution of Magothy sequences and facies indicates stability of this deltaic depositional system over ~4Myr despite low-amplitude (less than 25m) sea-level variations. Widespread facies correlation provides a predictable distribution of aquifer sands and confining-unit clays tied to sea-level changes on complex deltaic facies. [ABSTRACT FROM AUTHOR]

In this study, an Upper Cretaceous sedimentary sequence in the Anaran Anticline (located in the central Zagros) is investigated to assess planktonic foraminiferal biozonations and implications for sea level changes. The thickness of this sequence is about 215 m, characterized by shales and limestones with thin marly limestone intercalations. In total, 51 species and 22 genera of planktonic foraminifera in 12 biozones spanning the middle Campanian to late Danian ages were delineated in the studied sequence. Additionally, planktonic foraminiferal morphological models, species abundance percentages, and the planktonic/benthonic foraminiferal ratio (P/B) ratios were assessed to reconstruct changes in sea level. The statistical studies on the different genera and species and the P/B ratio from the base to the top of the sequence indicate sea level transgressions during the middle Campanian and Maastrichtian in the Contusotruncana plummerae Interval Zone, Radotruncana calcarata Total Range Zone, Globotruncanella havanensis Partial Range Zone, Globotruncana aegyptiaca Interval Zone, Contusotruncana contusa Interval Zone, and part of the Abathomphalus mayaroensis Interval Zone. Moreover, species belonging to the deep-water morphotype (G. arca, G. hilli, G. linneiana, and G. ventricosa) are mostly present. Furthermore, two intervals of this sequence are associated with falling sea levels: 1) at the Campanian/Maastrichtian boundary in the middle of the Gansserina gansseri biozone; 2) from the late Maastrichtian close to the Cretaceous/Paleogene boundary with marly lithology. [ABSTRACT FROM AUTHOR]

The Eocene carbonates of the south Sabzevar region in central Iran hold a rich Alveolina assemblage. Nine species including A. globula, Alveolina sp. 1, Alveolina aff. globula, A. regularis, A. globosa, A. pasticillata, A. laxa, A. pisiformis and A. cf. decipiens are identified through detailed analysis in thin section. The biostratigraphy obtained points to the early Ypresian Shallow Benthic Zones SBZ6 and partly SBZ7, indicating the occurrence of a lower Eocene carbonate system. The Alveolina biostratigraphy is correlated to the calcareous nannofossil biostratigraphy, and is assignable to the middle part of the NP10 Zone and especially with the CNE2 biozones. The evolutionary trends of A. globula and its dispersal through thewestern and central Neo-Tethys Ocean during theYpresian is here considered in relation with the occurrence of Alveolina sp. 1. [ABSTRACT FROM AUTHOR]

We have integrated southern mid- and high-latitude (Austral) radiolarian biozonations with the well-established low-latitude (Tropical) biozonation using new biostratigraphic and magnetostratigraphic constraints on radiolarian bioevents in the Southwest (SW) Pacific, Southeast (SE) Indian and Northwest (NW) Atlantic Oceans. Our primary study sites include Mead Stream, New Zealand, and DSDP Sites 277 and 207 (SW Pacific; 45-54°S at 50 Ma), ODP Site 752 and IODP Site U1514 (SE Indian; 50°S at 50 Ma), and IODP Site U1403 (NW Atlantic; 30°N at 50 Ma). The Austral and Tropical zonal schemes have been calibrated to GPTS2020. We introduce new zonal codes to rectify current confusion surrounding use of "RP" zones. Austral zones are codified as "RPA" zones and Tropical zones are codified as "RPT". Our study finds that radiolarian datums are generally isochronous within the mid-latitude SW Pacific and SE Indian Oceans from Paleocene to middle Eocene and are also isochronous in the high-latitude Southern Ocean (>60°S paleolatitude) over the late middle Eocene to Oligocene interval of overlap. Older radiolarian assemblages are not known from the Southern Ocean. Early-middle Paleocene radiolarian assemblages in the SE Indian Ocean (zones RPA2-RPA5) differ from coeval SW Pacific assemblages by lacking significant numbers of Cretaceous survivors. The reasons for this difference are uncertain. Although the late Paleocene-Eocene radiolarian assemblages in the SW Pacific and SE Indian Ocean lack many low-latitude index species, the timing of Indian Ocean bioevents agrees better with low-latitude biozonations than the SW Pacific, suggesting a stronger connection with low-latitude watermasses. Assemblages from NWAtlantic IODP Site U1403 include numerous low-latitude index species and can be correlated with zones RPT6-RPT13. Many of the species transitions in biostratigraphically important Eocene lineages, however, occur later than in lower latitudes. [ABSTRACT FROM AUTHOR]

The Gachsaran Formation from the Fars Group has a vast extent in Saudi Arabia, United Arab Emirates and Qatar (Dam Formation). It extends from the Zagros Folded Belt Zone in the south of Iran to the north of Iraq, and even to northeast Syria (Fatha Formation). In order to eliminate the ambiguities of the proposed age and cover the regional information misplacements in cases where biostratigraphy studies can be effective, surface outcrops of these deposits were investigated in three stratigraphic sections near the border of Iran and Iraq, in the area behind the mountains of the Lurestan region (Posht-e-Kuh arc). According to similar results obtained in two other sections, the age of the Gachsaran Formation in the studied region is considered to be Early Miocene (Late Burdigalian). Comparison of the results of this study with biostratigraphic studies from other parts of the Middle East, which includes 16 study areas, shows that the Gachsaran Formation in Iran and its equivalent formations (Fatha and Dam) in neighboring countries have an age range of early Miocene (Aquitanian-Burdigalian) and even Burdigalian. This age has been determined by comparing the biological contents of the Gachsaran Formation with valid official biozones, as well as the presence of the index fossil Borelis melo curdica, to cover the information gap in the area. Isotopic studies of these sections in the region show that the maximum age of these sediments is early Miocene (Burdigalian), and this confirms the results of biostratigraphic studies. [ABSTRACT FROM AUTHOR]

New sedimentological observations in the Lower Cretaceous of the Silesian Unit and integrated biostratigraphy based on calcareous nannofossils, dinoflagellate cysts, calpionellids and foraminifers have brought new insight to the stratigraphy of the Cieszyn section. The oldest exposed strata of themudstone facies of theCieszyn Limestone Formation are of early Berriasian age, based on calcareous nannofossil evidence. This work proposes that the Jurassic-Cretaceous boundary reported by previous authorswas based on reworked microfossils. The detritic facies of the Cieszyn Limestone Formation, typically dominated by detritic-limestone turbidites, appears to be completely missing. Instead, a thick body with combined slump and slide features, of Berriasian-Valanginian age, forms the transition with the overlying lower Valanginian strata of the Hradišt Formation. The slump/slide body represents a local facies, deposited on a fault scarp related to fault-controlled extension of the Proto-Silesian Basin floor. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous Abtalkh Formation of the Kopet-Dagh Basin (northeastern Iran) was studied in four stratigraphic sections (Bahadorkhan, Hammam Galeh, Type section and Shorab). All sections display limestones, shales and calcareous shales. The Bahadorkhan section is approximately 480 m thick. We identified 32 planktonic foraminifera species belonging to 13 genera in 6 biozones: 1. Dicarinella asymetrica Total Range Zone, 2. Globotruncanita elevata Partial Range Zone, 3. Contusotruncana plummerae Interval Zone, 4. Radotruncana calcarata Total Range Zone, 5. Globotruncanella havanensis Partial Range Zone and Globotruncana aegyptiaca Interval Zone. Based on foraminiferal biostratigraphy, the Bahadorkhan section was dated to the latest Santonian to late Campanian. This study identifies 11 genera and 25 species of planktonic foraminifera in the 1500mthick HammamGaleh section, spanning 7 biozones: 1. Dicarinella asymetrica Total Range Zone, 2. Globotruncanita elevata Partial Range Zone, 3. Contusotruncana plummerae Interval Zone, 4. Radotruncana calcarata Total Range Zone, 5. Globotruncanella havanensis Partial Range Zone, 6. Globotruncana aegyptiaca Interval Zone, 7. Gansserina gansseri Interval Zone. Latest Santonian to late Campanian ages have been established for the Abtalkh Formation. The type locality of the Abtalkh Formation is 750mthick and contains 31 planktonic foraminiferal species belonging to 12 genera. Based on this fossil content, we identified 6 biozones. The age of the formation is estimated to be the latest Santonian to late Campanian, as for the Bahadorkhan type section. The Shorab section of the Abtalkh Formation is 990mthick. In this section, 19 species belonging to 10 genera were identified, as were 5 biozones: 1. Globotruncanita elevata Partial Range Zone, 2. Contusotruncana plummerae Interval Zone, 3. Radotruncana calcarata Total Range Zone, 4. Globotruncanella havanensis Partial Range Zone, 5. Globotruncana aegyptiaca Interval Zone. Based on this fossil assemblage, the Shorab section dates to the early to late Campanian. [ABSTRACT FROM AUTHOR]

We discriminated Bashkirian to Moscovian (Pennsylvanian) conodont faunas including 19 species of nine genera from theOmi Limestone in theAkiyoshi Terrane and established the following four conodont zones in ascending order, the Declinognathodus noduliferus, Neognathodus symmetricus-Idiognathoides sulcatus sulcatus, "Streptognathodus" expansus, and Mesogondolella clarki Zones. These conodont zones are correlated locally and internationally. The Bashkirian/Moscovian boundary horizon is probably located at the upper part of the "S." expansus Zone. We further systematically treated obtained conodont species, herein. [ABSTRACT FROM AUTHOR]

The Englewood Formation comprises four distinct lithostratigraphic members formally named, in ascending stratigraphic order: the Crook City, Little Crow, Griffis Canyon and Mickelson members. The Crook City Member is a yellow to gray, silty and dolomitic shale. The Little Crow Member is a pinkish-red, silty to argillaceous to fossiliferous dolomitic limestone. The Griffis Canyon Member is a dull yellow, stromatolitic, argillaceous, dolomitic microbialite. The MickelsonMember is a yellow, slabby, thin bedded, argillaceous to silty fossiliferous limestone. The Crook City, Little Crow and Griffis Canyon members have gradational contacts with each other, possess conodonts of the Bispathodus aculeatus aculeatus Zone and comprise the upper Famennian Devonian sequence of the Englewood. Aregional disconformity lies at the base of theMickelson Member, which yielded conodonts of the Siphonodella sandbergi Zone and comprises the lower TournaisianMississippian sequence of the Englewood. The basal beds of the Pahasapa Formation rest on a regional disconformity on the top of theMickelson Member. The Pahasapa beds comprise gray, massive to thickly bedded, crinoidal, vuggy, dolomitic limestone that possess conodonts of the Siphonodella crenulata Zone, of early Tournaisian, EarlyMississippian in age. The Englewood Formation in the Black Hills region represents a shallow marine carbonate with interbedded, bioturbated siltstones, argillaceous and microbial limestones, fossiliferous pack-wackestones and coral boundstones. These carbonate deposits are age equivalent to organic- rich black shales in the Williston, Sappington and South Alberta petroleum basins to the northwest. [ABSTRACT FROM AUTHOR]

The new Larger Benthic Foraminifera Pseudochoffatella minima n. sp. is described from the uppermost Barremian? to early upperAptian of the Taft Formation of theYazd Block, Central Iran. It differs from the upperAptian-lowermostAlbian type-species P. cuvillieri Deloffre by its reduced dimensions (test size, chamber height, diameter of proloculus), and can be considered as its direct ancestor. P. minima n. sp. occurs in wackestone in often monotypic assemblages. Differences to Balkhania balkhanica Mamontova (syn. Pseudochoffatella giganteaKaever), an allied taxon recorded from the lowerAptian of the Tirgan and Taft formations are constrained. P. minima n. sp. represents the third species of the genus besides the type-species P. cuvillieri Deloffre and the Cenomanian P. algeriana Peybernès, Calvez and Ciszak. [ABSTRACT FROM AUTHOR]

Recovery of P1 elements of Streptognathodus isolatus and associated nodose streptognathodids from the Laborcita Member of the Bursum Formation near Tularosa, New Mexico clarifies placement of the Carboniferous/Permian boundary in the northern SacramentoMountains. Conodont elements, fish teeth, and dermal plates are abundant in a thin (4.8m) highstand carbonate succession located approximately 70 m above the base of the 130 m-thick Laborcita Member. The fauna represents the oldest Permian conodonts discovered thus far inNew Mexico and in a basin associated with theAncestral RockyMountains orogen. The occurrence of S. isolatus in this tectonic and geographic setting further demonstrates its utility in defining and correlating the base of the Permian System on a global scale. Occurring with S. isolatus in earliest Asselian strata is S. barricki n. sp., which is described herein. [ABSTRACT FROM AUTHOR]

An integrated, high sample-density biostratigraphic study of the Middle to Upper Jurassic Marrat, Dhruma, Sargelu, Najmah and Jubaila formations of Kuwait was completed on approximately 1600 core samples for palynology, calcareous nannofossils, and foraminifera (thin sections) in twenty wells. Five established Tethyan nannofossil zones are integrated with six recently recognized microfossil zones and two palynological zones, enabling chronostratigraphic correlations within Kuwait and to the equivalent units of Eastern Saudi Arabia. Paleoenvironmental and paleogeographic interpretation is carried out giving some insights to the timing of activation of the Rimthan Arch and formation of the Gotnia Basin, from the Bajocian to Kimmeridgian. The Dhruma Formation is assigned an early to late Bajocian age, nannofossil zone NJT 10 (upper part subzone NJT 10a) based on the co-occurrence of C. superbus and W. manivitae. The Sargelu-Dhruma Transition is of late Bajocian to early Bathonian age (NJT 10b nannofossil subzone to NJT 11 Zone) on the basis of the LO of C. magharensis. Conoglobuligerina dagestanica defines the Bathonian upper boundary within the overlying Sargelu Limestone, which also shows G. calloviensis, suggesting an early Callovian age. This unit shows an increase in microfossils and the absence of nannofossils which enables the designation of the G. calloviensis / G. bathoniana planktic foraminifer zone. The overlying Najmah Formation is subdivided into the Najmah-Sargelu transition, the Lower Najmah and Upper Najmah members, of Callovian to Oxfordian age, with planktonic foraminiferal bioevents such as the LO of G. calloviensis, G. bathoniana, and G. oxfordiana. A sparse calcareous nannofossil assemblage which includes A. helvetica and C. deflandrei suggests the Callovian to Oxfordian NJT 11 to NJT 13 Zones for this formation. The topmost Upper Najmah Shale is dated as Kimmeridgian on the basis of the FO of the dinoflagellate Circulodinium spp. with the overlying peloid-skeletal wackstone and microbial-ooid-skeletal, grain-dominated packstones Najmah Limestone mainly characterized by benthic foraminifera assemblages. This unit unconformably underlies the laminated, organic-rich calcareous shales of the Kimmeridgian Jubaila Formation. The succession exhibits marine paleoenvironments ranging from inner to middle neritic for the Dhruma Formation and Sargelu- Dhruma Transition, middle to outer neritic for the Sargelu Limestone and Lower Najmah Shale, with predominantly outer neritic conditions for the Upper Najmah Shale. Shallower transitional to inner neritic has been interpreted for the Najmah Limestone whereas the Jubaila Formation was deposited in deeper middle to outer neritic conditions. The onset of tectonic activity that formed the Gotnia Basin started during the deposition of the Dhruma Formation, with down-faulting prevailing along the north edge of the Rimthan Arch. Accommodation space was never filled, up to the deposition of the Gotnia Formation. [ABSTRACT FROM AUTHOR]

Benthic foraminiferal assemblages dominated by Alveolina species from the Ypresian (Ilerdian-Cuisian) are studied herein from numerous localities of Iran and Turkey. From these successions, highly diversified assemblage of 58 alveolinid species are identified along with their detailed biostratigraphical application, which resulted in the recognition of eight shallow benthic zones (SBZ5-SBZ12). Our findings are based upon the distribution ranges of Alveolina from the Ilerdian-Cuisian sediments in Iran (Central Tethys) that are considered to have a strong affinity with their coeval fauna in Turkey (Western Tethys). In this study, the wide expansion ranges of Alveolina permit us to achieve a high-resolution biostratigraphy and apply the shallow benthic zones of the peri-Mediterranean region (Western Tethys) to the Ilerdian-Cuisian successions in Iran (Central Tethys). Nevertheless, the distribution of some Alveolina species, even the zonalmarkers consisting of Glomalveolina lepidula, Alveolina ellipsoidalis, A. pisiformis, A. laxa, A. subpyrenaica, A. varians, A. fornasinii and A. canavarii are found occurring at younger stratigraphic levels in Iran and/or Turkey than in thewestern European shallow marine deposits. [ABSTRACT FROM AUTHOR]

A measured section of the Upper Pennsylvanian-Lower Permian Riepe Spring Limestone at Spruce Mountain Ridge, Elko County, Nevada, presents a stratigraphic record of the coastal evolution and the shoreline-to-open marine depositional history of a portion of the post-Antler foreland. The 420 m thick “North Spruce Mountain Ridge” (NSMR) section consists of highly variable lower Missourian (Upper Pennsylvanian)-uppermost Wolfcampian (Lower Permian) strata. The NSMR section, which follows Section 1 of Hope (1972), was remeasured and sampled by the authors for stratigraphic revision of the Hope’s Section 1 with an accompanying biostratigraphic study of the fusulinid and conodont assemblages. As a result, a new lithostratigraphic interpretation of the Riepe Spring Limestone at Spruce Mountain Ridge, consisting of three lithologically distinguishable informal members, is presented herein. The so-called lower, middle, and upper informal members of the Riepe Spring Limestone are primarily composed of thick, alternating units of limestone, calcareous sandstone, and quartzose conglomerate. The mixed carbonate-siliciclastic strata of the NSMR section are biostratigraphically constrained by a fusulinid succession comprising eight assemblage zones (lowest to highest stratigraphically): Eowaeringella assemblage zone; Triticites preoryziformis n. sp. assemblage zone; Triticites cf. jacksboroensis assemblage zone; Triticites cullomensis-Dunbarinella kauffmani assemblage zone; Triticites creekensis-Triticites pinguis assemblage zone; Schwagerina wellsensis assemblage zone; Eoparafusulina linearis assemblage zone; Schwagerina franklinensis-Schwagerina nowitzkii n. sp. assemblage zone. Fusulinid collections include specimens from new field samples and loaned material from the Smithsonian National Museum of Natural History’s Douglass-Henbest collection. Descriptions of 39 species are provided, including two species of Eowaeringella, 14 species of Triticites, three species of Pseudofusulinella, one species of Dunbarinella, one species of Douglassites, one species of Schubertella, one species of Pseudofusulina, two species of Cuniculinella, seven species of Schwagerina, three species of Alaskanella, two species of Pseudoschwagerina, one species of Eoparafusulina, and one species of Leptotriticites. New early Missourian-late Wolfcampian taxa described herein include Eowaeringella nevadaensis n. sp., Eowaeringella riepensis n. sp., Triticites contrariatheca n. sp., Triticites postspringvillensis n. sp., Triticites preoryziformis n. sp., Pseudofusulinella wahlmani n. sp., Cuniculinella hiatus n. sp., Schwagerina celeris n. sp., Schwagerina margerumi n. sp., Schwagerina nowitzkii n. sp., Alaskanella hopei n. sp., Alaskanella lata n. sp., and Leptotriticites nevadaensis n. sp. [ABSTRACT FROM AUTHOR]

The foraminifera of the Gault Clay Formation, exposed in the Munday's Hill Quarry (Leighton Buzzard, Bedfordshire, UK), are described. This quarry, which is worked for the underlying Woburn Sands, is periodically 'refreshed' and the Gault Clay overburden removed. This cleaning of the quarry was undertaken in 2018 and provided access to a fresh clay succession. An 11.4m section of the Gault Clay Formation was logged and samples collected for micropalaeontological analysis, ranging from the Hoplites spathi Subzone to the Hysteroceras varicosum Subzone. A total of 58 species were identified from a total of 11,345 foraminifera examined in 20 samples. Two distinctive assemblages are evident; the Lower Gault Clay contains abundant aragonitic foraminifera, while the Upper Gault Clay is dominated by agglutinated foraminifera. This distribution is repeatedly recorded across South-Eastern England and is likely due to ecological constraints such as water depth, but taphonomic processes cannot be dismissed. The succession at Munday's Hill Quarry is compared to comparable successions in East Anglia, Sussex (Glyndebourne Borehole) and Kent (Copt Point, Folkestone). [ABSTRACT FROM AUTHOR]