Abundance In Zone Research Articles

The Later Holocene Foraminifera of Liverpool Bay (Bae Lerpwl), British Isles: Morphospecies and Community Level Patterns

Abstract Two cores were studied from Liverpool Bay (∼40 m water depth). The lowest 80 cm of ISLF13 (290 cm long) comprised clay, gypsum and pyritised foraminifera (Surface Layer 2 Member, gypsiferous lithofacies GLF) from a tidal flat dominated by Cribroelphidium excavatum. Perturbation Detection Analysis (PDA) found two ISLF13 GLF abundance biozones (ABs) with assemblages in stasis. ISLF16 (80 cm long) and between 30–202 cm in ISLF13 were open marine, sandy with gastropods and bivalves (Surface Layer 1 Member, shelly sand lithofacies SSLF). Assemblages in the SSLF sections differed, despite their proximity. That in ISLF13 comprised dominant C. excavatum with lesser Ammonia batava, Asterigerinata mamilla, Cibicides refulgens and Bulimina elongata. PDA identified two ISLF13 SSLF ABs, both in growth stages. The ISLF16 assemblage was co-dominated by C. excavatum, A. mamilla and A. batava from a single AB in stasis. This difference might reflect sorting. Asterigerinata murraynhaynesi n. sp. is described.

Palynozonation of Akukwa-2 Well, Anambra Basin: Implications for Age and Paleoenvironment

Palynological examination of twenty (20) ditch shale samples from sedimentary succession penetrated by Akukwa-2 Well at depth interval of 3,296 - 3,850 m was undertaken to investigate the occurrence of Palynomorph in the sediments of Anambra Basin with a view to determining the age of the sediments and reconstruct the depositional paleoenvironment. Standard Palynological procedure was followed and the samples were processed using the conventional acid maceration, alkali treatment and staining methods. The oxidized residues were sieved with 5micron nylon sieves using digital Sonifier 450 machine and mounted on glass slides with Norland adhesive gel. Laborlux 12 (Ernst Leitz) transmitting light microscope was used for identification and counting or the palynomorphs. The palynological analysis was done using the population and species of pollen grains, spores and dinoflagelate. The analyzed palynological slides yielded forty nine (49) palynomorphs species identify in the ditch samples, forty (40) were Miospores (pollen and spores) and nine were Dynocysts. However, some diagnostic forms that are stratigraphically useful are present and are used for the palynozonation. Delineation of the well section produced three main palynological zones based on stratigraphic distribution. Zone 1 characterized by the quantitative base appearance of Triorites Africaensis Assemblage indicating Marginal Marine paleoenvironment and of Turonian age; Zone 2, marked by Droseridites Senonicus assemblage also of Marginal Marine but of Coniacian age, Zone 3, marked by Milfordia spp. Acme Zone, purely Marine and of Campano- Maastrichtian age. The study further reveled that Palynomorph recovery in Akukwa-2 well was not that impressive both in terms of abundance and preservation. In most cases, the macerals present seems to indicate high geothermal effect suggesting that some of the kerogen might have been overcooked to imply inability  to generate hydrocarbon or such generated hydrocarbon have turned into carbon.

Palynostratigraphy and paleoenvironmental inferences of the Jurassic successions, Darag Basin, Gulf of Suez, Egypt

The present study shows the advantage of the palynostratigraphy and paleoenvironmental inferences concepts in subdividing and interpreting the depositional environment of the Jurassic rocks, depending on two sections in two boreholes drilled in the Darag Basin, Egypt. Six Jurassic rock units representing the mixed siliciclastic and carbonate sediments were recognized from top to base; the Tauriat, Arousiah, Kehailia, Safa, Shusha and Rajabiah formations. The palynomorph assemblage associated with moderately diversified dinoflagellate cysts and fewer sporomorphs, show poor to fair preservation. About 20 dinoflagellate cysts, 8 pollen, and 3 pteridophytic spore species have been recorded. The Jurassic rocks are originated from the late Jurassic (early Oxfordian) and early (Toarcian - Aaleneian) based on the recovered marker taxa. The studied sections are differentiated into six biozones, Systematophora sp. (Callovian-Oxfordian), Gonyaulacysta jurassica (Callovian), Dichadogonyaulax sellwoodii (Late Bathonian), Sentusidinium sp. (Early Bathonian), Pareodinia ceratophora (Bajocian) and Psilate spores, Classopollis and Sphaeripollenites Acme Zone (Toarcian-Aalenian).According to the Particulate Organic Matter (POM) composition in the studied wells, the palynofacies assemblages led to identifying three depositional settings, the palynofacies −1 (PFA-1), which is characterized by opaque phytoclasts and high volume of spores and pollen grains was deposited in a marginal shallow-marine environment during a relative sea-level fall. The PFA-2 is composed of brown phytoclasts, moderate Amorphous Organic Matter (AOM) with pollen grains and dominated dinocysts. It was deposited during a slight sea level rise in a proximal inner neritic environment. Simultaneously, the PFA-3, which was dominated by AOM and dinoflagellate cysts with moderate brown phytoclast content, was deposited as a distal inner neritic environment during a relatively high relative sea level.

Environmental change in the late Permian of Queensland, NE Australia: The warmup to the end-Permian Extinction

The upper part of the upper Permian succession in the Bowen Basin of Queensland, NE Australia, was investigated to ascertain the timeline and character of environmental changes in this high southern palaeolatitudinal setting leading up to the End-Permian Extinction (EPE). The study focused on (in ascending order) the Peawaddy Formation, Black Alley Shale, and Bandanna Formation, and laterally correlative units. In the western Bowen Basin, the base of the Peawaddy Formation (257 Ma) records the onset of thrust loading and volcanic activity associated with the Hunter-Bowen contractional orogeny. The Peawaddy Formation comprises a series of coarsening-upward, terrigenous clastic intervals interpreted as the product of repeated progradation of deltas into shallow, open marine environments. The overlying Black Alley Shale also comprises multiple deltaic coarsening-upward cycles, which accumulated in stressed, restricted marine environments. The uppermost Bandanna Formation and equivalents formed in extensive coastal plain to estuarine environments. All three formations accumulated under the influence of explosive volcanic activity from the emerging continental volcanic arc to the east of the foreland basin. Volcanism peaked during deposition of the Black Alley Shale around the Wuchiapingian–Changhsingian transition. Abundant dispersed gravel and glendonites (calcite pseudomorphs after ikaite) indicate that the Peawaddy Formation formed under the influence of cold conditions and possible glacial ice (P4 Glaciation; Wuchiapingian Stage). Direct evidence of cold conditions ends at the top of the Peawaddy Formation (254.5 Ma); however, Chemical Index of Alteration (CIA) data suggest that surface conditions remained cold through the accumulation of the Black Alley Shale, and the lower Bandanna until c. 253 Ma, before gradually rising through the upper Bandanna Formation. The end of P4 glaciation is also characterized by a major spike in the abundance of marine acritarchs ( Micrhystridium evansii Acme Zone), reflecting the development of a regional restricted basin of elevated nutrient concentrations but reduced salinity. In contrast to this short interval of stressed marine conditions, the fossil floras indicate remarkably consistent terrestrial ecosystems throughout the late Lopingian until the EPE. The terrestrial EPE is recorded by a distinctive, laminated mudrock bed (‘Marker Mudstone’) that records a palynological ‘dead zone’ above the uppermost coal seam or equivalent root-penetrated horizon followed by spikes in non-marine algal abundance. Overall, the time interval 257–252 Ma represented by the studied succession does not record a simple monotonic change in palaeoenvironmental conditions, but rather a series of intermittent stepwise changes towards warmer, and more environmentally stressed conditions leading up to the EPE in eastern Australia. • Lopingian (257–251.9 Ma) succession investigated in Bowen Basin, northeastern Australia, Several major palaeoenvironmental changes are recorded, • P4 Glaciation lasted until 254.5 Ma, cold climate persisted until 253 Ma, • Major algal bloom associated with restriction of marine circulation occurred at 254.5 Ma, • Climate warmed after 253 Ma towards end-Permian, but continental flora was stable until abrupt collapse at c. 252 Ma

Variation of bacterial community and alkane monooxygenase gene abundance in diesel n-alkane contaminated subsurface environment under seasonal water table fluctuation

n-Alkanes, the main component of diesel fuel, are common light non-aqueous phase liquids (LNAPLs) that threaten ecological security. The subsurface from vadose zone, through fluctuating zone, to saturated zone, is a critical multi-interface earth layer which significantly affects the biodegradation processes of n-alkanes. A pilot-scale diesel contaminated aquifer column experiment has been undertaken to investigate the variations of bacterial community and alkane monooxygenase (alkB) gene abundance in these zones due to water-table fluctuations. The n-alkanes formed a layer immediately above the water table, and when this was raised, they were carried upwards through the fluctuating zone into the vadose zone. Water content and n-alkanes component C10-C12 are main factors influencing bacterial community variation in the vadose zone, while C10-C12 is a key driving factor shaping bacterial community in the fluctuating zone. The most abundant bacterial phyla at all three zones were Proteobacteria, Firmicutes and Actinobacteria, but moisture-niche selection determined their relative abundance. The intermittent wetting cycle resulted in higher abundance of Proteobacteria, and lower abundance of Actinobacteria in the vadose and fluctuating zones in comparison to the control column with a static water-table. The abundances of the alkB gene variants were relatively uniform in different zones, probably because the bacterial populations harboring alkB gene are habituated to biogenic n-alkanes rather than responding to diesel fuel contamination. The variation in the bacterial populations with height due to moisture-niche selection had very little effect on the alkB gene abundance, possibly because numerous species in both phyla (Proteobacteria and Actinobacteria) carry an alkB gene variant. Nevertheless, the drop in the water table caused a short-term spike in alkB gene abundance in the saturated zone, which is most likely associated with transport of solutes or colloids from the fluctuating zone to bacteria species in the saturated zone, so a fluctuating water table could potentially increase n-alkane biodegradation function.

The influence of the inter-tropical convergence zone on the Orinoco River and Late Quaternary tropical planktonic foraminiferal assemblages

Although deep-water oil and gas exploration offshore eastern Trinidad is becoming prevalent, the use of ecostratigraphy around eastern Trinidad are limited mostly to neritic water depths. Changes in planktonic foraminiferal assemblages of Core BGT086, offshore eastern Trinidad, are used here to indicate biozonal events useful for deep-water (>1000 m water depth) exploration. Decreased proportional abundances of Globigerinella obesa and Globigerina bulloides mark the southward migration of the inter-tropical convergence zone (ITCZ) during the Younger Dryas (YD). A decrease in species richness and Globigerinoides ruberwhite proportional abundance is consistent with rising temperature during the YD. During Biozone Z2, nutrient-preferring species (G. bulloides, Neogloboquadrina dutertrei) declined in proportional abundance, while G. ruberpink increased in proportional abundance, reflecting the arrival of the ITCZ in the area. Decreases in mean diversity (measured using the Shannon Function, H) and evenness (equitability index, E), and an increase in mean dominance (max pi) support the claim that the ITCZ arrived in the area after the YD. A sudden increase in Globorotalia menardii proportional abundance marked the start of Biozone Z1, at which time there was a change from a stressed community to a less stressed one. Boundaries of SHE abundance biozones coincided with noticeably enhanced assemblage changes, being consistent with the southward migration of the ITCZ and the onset of Biozone Z1. The mean value of the pairwise assemblage turnover index (ATIs) is here used as a proxy for what we term 'assemblage stability'. Comparisons of mean planktonic foraminiferal ATIs from Core BGT086 and six other nearby tropical piston cores (Cores 1, 2 and 3 off NW Tobago, and En20-2, En20-10 and En20-16 from the Leeward Islands, Lesser Antilles) showed no statistical difference in assemblage stabilities within similar planktonic foraminiferal biozones. Kruskal-Wallis tests determined a significant difference in median ATIs values when all seven cores' ATIs were used, but the difference was not significant when data above the YD boundary (i.e., Biozone Z) were used. The lowered nutrient influx from the Orinoco River due to the arrival of the ITCZ in the area after the YD would have triggered a stable environment for planktonic foraminiferal assemblages. This implies that caution must be used to ensure data from the same biozone is used when analyzing assemblage stabilities of planktonic foraminifera.

Palaeoecological and palaeobiogeographic implications of Middle‐Late Eocene ostracods from the Qattamiya area, North Eastern Desert, Egypt

In an attempt to define the palaeoecology and palaeobiogeography of the Middle‐Late Eocene rock units in the North Eastern Desert of Egypt, 121 rock samples of three representative localities, namely, Wadi Degla, Gebel Abu‐Shama, and Gebel Qattamiya sections were collected and investigated. Qualitative and quantitative analysis of ostracods associations and sedimentological data were used to identify three ostracod biozones; two acme zones (Cytherella tarabulusensis and Loxoconcha vetustopunctatella) of the Middle Eocene age and one assemblage zone (Xestoleberis subglobosa–Uromuellerina saidi) of Middle‐Late Eocene age, reflecting palaeoenvironments in the study area. The Cytherella tarabulusensis Zone, located at the bottom of all sections, is characterized by restricted shallow water, low dissolved oxygen, high salinity, and water depth below 100 m. The Loxoconcha vetustopunctatella Zone, located in Wadi Degla and Gebel Qattamiya sections, is characterized by shallow normal warm waters in the range of 20–50 m, whereas Xestoleberis subglobosa–Uromuellerina saidi Assemblage Zone, located in all studied sections, reflects restricted shallow water with a reduced dissolved oxygen condition palaeoenvironment. Palaeobiogeographically, the recorded ostracod assemblage exhibits similarities with those recorded in the Middle East and North and East Africa bioprovinces.

Partially protected areas as a management tool on inshore reefs

Partially Protected Areas (PPAs) are a widely-used management tool, yet comparatively little is known about their effectiveness compared to more commonly studied No-Take Marine Reserves (NTMRs). Here, we examine the efficacy of two kinds of PPAs (with and without spearfishing) within the Great Barrier Reef Marine Park (GBRMP) that are subject to a range of fishing limitations, and assess their utility as a marine park zoning and fisheries management tool. Fish abundance, size, and habitat composition were compared inside PPAs and NTMRs on inshore reefs of the central GBR. Fish abundances were lower inside PPAs relative to adjacent NTMRs for primary fishing targets, with no detectable effects for secondary targets and non-targets, or for species richness. Fish assemblages differed amongst zones, but these variations were minor compared to regional variations in species composition. Partially Protected Areas supported 46%–69% of the relative abundance of total primary targets compared to adjacent NTMRs, with no evident increase in abundance in zones where spearfishing was prohibited. There were no reductions in the size of two key target species: coral trout (Plectropomus spp.) and stripey snapper (Lutjanus carponotatus) inside PPAs, and only stripey snapper had significant reductions in abundance inside PPAs compared to NTMRS. Habitat and biophysical characteristics (especially topographic complexity) were strong drivers of fish abundance, but the relative influence of zone was greater for target species compared to non-targets. This study provides novel data on PPAs and highlights their utility as a spatial management tool in contributing to conservation and fisheries management goals.

Elucidating the archaeal community and functional potential in two typical coastal wetlands with different stress patterns

Archaea play dominant roles in nutrient cycling, but the archaeal community and function in coastal wetlands with different stress patterns remain poorly understood. Here, two typical coastal wetlands of the Yellow River estuary, Zone A with only tidal erosion and Zone B with runoff and tidal invasion, were selected to explore the possible differences in archaeal community and function and evaluate the influential factors. Compared with Zone B, Zone A had higher levels of total nitrogen, available phosphorous (AP) and pH. Thaumarchaeota was the most abundant archaeal phylum, followed by Euryarchaeota in Zones A and B. Candidatus_Nitrosopelagicus (30.85% in Zone A, 36.04% in Zone B) and Candidatus_Nitrosopumilus (24.10% in Zone A, 39.01% in Zone B) were the dominant ammonia-oxidizing archaea in both zones, and Haloarcula and Haloferax were the dominant denitrifying halophilic archaea in Zone A. Organisms from methanogenic genera Methanobrevibacter, Methanocorpusculum and Methanosarcina were enriched in Zone A. Anaerobic methanotrophic Candidatus_Methanoperedens (ANME-2d) had relatively low abundance in Zones A and B. These archaea were the key factors in maintaining the carbon and nitrogen cycles in coastal wetlands. Moreover, nitrification was relatively active in Zone B, and denitrification and methanogenesis dominated in Zone A. Redundancy analysis revealed that AP, NH4+–N, pH, salinity and moisture played important roles in the determination of archaeal community composition at the genus level. Microbial community and PICRUSt analysis indicated that the archaeal communities changed significantly, but the functions were relatively stable for both zones. This finding suggests that environmental selection in similar habitats could lead to functional convergence. The relative gene abundances of nitrate reductase were relatively high, indicating that aside from denitrification, a large amount of nitrite as an electron acceptor was present to perform nitrite-driven anaerobic methane oxidation via reverse methanogenesis. The findings help in understanding the impacts of different stress patterns on archaeal community composition and functional potential in coastal wetlands.

Soil organic matter and salinity as critical factors affecting the bacterial community and function of Phragmites australis dominated riparian and coastal wetlands

Soil salinization poses a great threat to the natural ecosystem and interferes with the structure and function of the biological community, resulting in different vegetation distributions. However, little attention is paid to the changes in microbial community in different wetland types with the same vegetation. In this study, the Yellow River Delta was used as a model because of its typical and extensive distribution of Phragmites australis-dominated saltwater and freshwater wetlands. We investigated the differences in the structure and function of bacterial communities, as well as their relationships with soil properties in coastal (Zone A) and riparian (Zone B) wetlands. Results showed higher salinity and pH in Zone A than Zone B (p < 0.05), whereas TN (p < 0.05) and SOM were lower than those in Zone B. Significant differences existed in microbial community composition between Zones A and B. The nitrifying-bacteria Nitrospira and norank_f_Nitrosomonadaceae had high abundance in Zones A and B. Alcanivorax, Halomonas, and Marinobacter were extensively distributed in Zone A, whereas Flavobacterium and Pseudomonas were dominant in Zone B, indicating the diversity characteristics of denitrifying bacteria. Conversely, methane-oxidizing bacteria Methylophaga were significantly higher in Zone A than in Zone B (p < 0.05), indicating that high salinity was conducive to aerobic methane oxidation and that the genetic diversity at strain level endowed it with a certain denitrification potential. Salinity and SOM played important roles in shaping microbial community at phylum and genus levels. The gene abundances related to xenobiotics metabolism and repair were high in Zone A, whereas the genes encoding energy metabolism and signal transduction were relatively high in Zone B. Denitrification was more favored for the low-salinity Zone B, whereas methane oxidation was enriched in the high-salinity Zone A. Therefore, our study emphasized the importance of an in-depth understanding of the microbial-community structure and function in Phragmites australis-dominated saltwater and freshwater wetlands.

Biostratigraphy of theMassospondylusAssemblage Zone (Stormberg Group, Karoo Supergroup), South Africa

AbstractThe Massospondylus Assemblage Zone is the youngest tetrapod biozone in the Karoo Basin (upper Stormberg Group, Karoo Supergroup) and records one of the oldest dinosaur dominated ecosystems in southern Gondwana. Recent qualitative and quantitative investigations into the biostratigraphy of the lower and upper Elliot formations (lEF, uEF) and Clarens Formation in the main Karoo Basin resulted in the first biostratigraphic review of this stratigraphic interval in nearly four decades, allowing us to introduce a new biostratigraphic scheme, the Massospondylus Assemblage Zone (MAZ). The MAZ expands upon the Massospondylus Range Zone by including the crocodylomorph Protosuchus haughtoni and the ornithischian Lesothosaurus diagnosticus as two co-occurring index taxa alongside the main index taxon, the sauropodomorph Massospondylus carinatus. With a maximum thickness of ~320 m in the southeastern portion of the basin, our new biozone is contained within the uEF and Clarens formations (upper Stormberg Group), however, based on vertebrate ichnofossils evidence, it may potentially extend into the sedimentary units of the lowermost Drakensberg Group. We do not propose any further subdivisions, and do not consider the Tritylodon Acme Zone (TAZ) as a temporal biostratigraphic marker within the MAZ. The MAZ is currently accepted to range in age between the Hettangian and Pliensbachian, however a faunal turnover, which observes an increase in the diversity of dinosaur clades, crocodylomorph, and mammaliaform taxa in the lower uEF, could reflect effects of the end-Triassic extinction event (ETE).

Characteristic Mollusc, Larger Foraminifera Findings and Environmental Interpretations of the Middle Eocene Kocaçay Formation Deposits Around Ayvalıca (Bayat, Çorum)

Although the Cankiri-Corum Basin was studied for various purposes such as geological, stratigraphical, tectonic, coal and oil exploration, studies on fossils are limited. Especially there have not been detailed studies on molluscs and larger foraminifera. The research area is located at the vicinity of Ayvalica (north of Cankiri-Corum basin). The Middle Eocene Kocacay formation, which outcrops in the Cankiri-Corum Basin, is widespread around Bayat Corum in the north of the basin, Sulakyurt Kirikkale in the west, Cicekdagi Kirsehir in the south and Sungurlu Corum in the middle of the basin. The formation is composed of conglomerate, carbonated sandstone, limestone and sandy marls and also includes rich larger foraminifera and molluscs. This study mainly focuses on taxonomy and environmental interpretations of Ostrea roncaensis (Partsch in coll. Bayan, 1870) de Gregorio, 1884, Velates perversus (Gmelin, 1791) species from Mollusca and Nummulites beaumonti d’Archiac and Haime, 1853, N. aturicus Joly and Leymerie,1848, N. perforatus (de Montfort, 1808) and Assilina exponens (Sowerby, 1840) species from larger Foraminifera. In addition, considering faunal features from bottom to top Ostrea roncaensis, Velates perversus, Nummulites aturicus and Assilina exponens Abundance Biozones were identified. The age range of the Kocacay Formation is determined as Lutetian-Bartonian. Lithological and faunal contents indicate that sediments of the Kocacay formation were deposited within lagoon to nummulitic sets in a shallow marine environment.

Neocomian Fahliyan formation carbonates in the oil well X2 (Dorood oil field, Persian Gulf): Biostratigraphic data from benthic foraminifera and algae

The Fahliyan Formation of the Khami Group is the most important oil and gas reservoir in southwestern Iran. The formation attains a thickness of 435.5 m in the oil well X2 in Dorood oil field, Persian Gulf. It is represented mainly by thin-bedded limestones. This formation unconformably overlies the evaporate late Jurassic Hith Formation and conformably underlies the Gadvan Formation. Integrated palaeontological and sedimentological studies supported by an analysis of 150 thin-sections led to the identification of 21 benthic foraminiferal genera dominated by agglutinated forms with an additional 8 algal genera. Two foraminiferal biozones of Berriasian through Hauterivian age include the Pseudochrysalidina (Dokhania) arabica acme zone and Pseudocyclammina lituus- Coscinoconus assemblage zone, and an algal zone includes the Salpingoporella annulata range zone have been recognized. The correlation of the lower Cretaceous petroleum source rock in the Persian Gulf with regions from Tethyan Realm is limited by the lack of the analog formation that can be used for comparison. In this way, the foraminiferal zones are correlated with coeval zones in south and southwest of Iran.

Exploring geophysical and palynological proxies for paleoenvironmental reconstructions in the Miocene of western Amazonia (Solimões Formation, Brazil)

Western Amazonia underwent important landscape changes during the Miocene due to the Andean uplift. Vast wetlands developed during this period and prevailed until the late Miocene. The evolution of this environment has been studied on the basis of sedimentology and paleontology. Here, we explore geophysical proxies (Gamma Ray, Electric Resistivity and Spontaneous Potential) from cores of the Solimões Formation (Brazil) to support paleoenvironmental reconstructions and potentially validate pollen taxa as environmental indicators. We show a general tendency from geophysical profiles to increasing energies in the depositional settings in agreement with lithologies during the accumulation history of the Solimões Formation. Moreover, ACME zone of the fossil palm Mauritia (Mauritiidites franciscoi) is associated with low energy environments, ACME of the extinct palm Grimsdalea magnaclavata is associated with similar environments but of a transitional nature, oscillating between high and low energies, and ACMEs of fossil Poaceae (Monoporopollenites annulatus) are mostly associated with high-energy environments of more active fluvial dynamics. These three phases appear in order from early, early/middle and middle/late Miocene in the cores, which we believe reflects the climax development and subsequent demise of the wetland system. Additionally, marine surfaces are detectable in the geophysical logging what could help sampling strategies for future studies on cores aiming to detecte these marine events.

Benthic foraminiferal biotic events related to the Paleocene–Eocene Thermal Maximum along the California margin

Abstract The faunal expression of the Paleocene-Eocene Thermal Maximum (PETM) is well documented in deep-sea sediments. However, few studies have examined continental margin sections, especially active margins. The Moreno and Lodo formations, Central California, were deposited along the eastern margin of a north-south trending forearc basin on the convergent margin of California during the Cretaceous through Late Cenozoic. The Tumey Gulch section which includes the Moreno and Lodo formations, is 80 m thick, contains the Paleocene-Eocene boundary and Carbon Isotope Excursion (CIE), and was deposited at abyssal to lower bathyal depths along an active continental margin. Benthic foraminiferal assemblages from this section record faunal changes related to the PETM and a younger hyperthermal, ETM3 which include a disruption of the gradual shallowing of water depths and fluctuation of the CCD. Associated with the onset of the hyperthermals in this section is a red clay-siltstone layer (low calcium carbonate content) and an increase in smoothly finished dissolution resistant agglutinated benthic foraminiferal species which corresponds with a rapid shoaling of the CCD. The subsequent overcompensation is identified by a rapid change to shallower benthic biofacies faunas, increased sediment rate, current activity, and terrestrial organic matter which is associated with increased weathering. Further analysis of the foraminiferal faunas identified the benthic foraminiferal extinction event (BEE), deep water agglutinated faunal acmes, and fluctuations in the calcareous foraminiferal assemblages which indicate changes in the paleoenvironmental conditions (e.g., dissolved oxygen, sedimentation rates and current activity, and the influx of organic carbon) during the PETM and ETM3. The Ynezian, Bulitian, and Penutian California benthic foraminiferal stages are recognized in the Tumey Gulch section as well as the benthic foraminiferal extinction event (BEE) which occurs at the onset of the PETM and is distinguished by the last appearance of Paleocene species and the first appearance of many Eocene species. Agglutinated foraminiferal species dominate the late Paleocene through early Eocene part of the section indicating deposition occurred at abyssal depths and/or below the CCD and that the environment was oligotrophic with moderate to low organic flux. The Glomospira acme zone is recognized at the base of the CIE and just above the top of red clay-siltstone layer and suggests increased terrestrial organic matter and elevated sedimentation rates. The abundance of calcareous species, specifically Bulimina alazanensis, followed by the appearance of opportunistic taxa (Tappanina and Quadrimorphina) in the PETM interval indicates deposition within the lower bathyal biofacies and/or a drop in the depth of the CCD. Eocene species characteristic of the Survivor faunal group (Anomalinoides, Bulimina, Cibicidoides, and Pleurostomella) appear above this event. Foraminiferal assemblages dominated by agglutinated foraminifera appear in sediments overlying the PETM interval and indicate deposition occurred at abyssal depths and below the CCD. Calcareous foraminiferal assemblages appear higher in the section as water depths decrease. The presence of a second red clay-siltstone layer associated with a second isotope excursion and faunal changes in the upper part of the section indicate the presence of another hyperthermal, ETM3.

Middle Jurassic palaeoenvironment and palaeobiogeography of the Tabas Block, Central Iran: palynological and palaeobotanical investigations

We performed a palynological study on Jurassic successions of the Hojedk Formation, Central Iran. The sampled material was recovered from well no. 233, South Kuchak-Ali area belonging to the Tabas Block. The lithology comprises 475.80 m of green–grey shales and sandstones. Palynological assemblages were recovered including spores, pollen grains, dinoflagellate cysts, woody debris and amorphous organic matter (AOM). Furthermore, 22 taxa of plant macrofossils were identified. We analysed 48 samples which resulted in identification of 13 spore species (belonging to 11 genera) and three pollen species (from three genera) with fair preservation quality. Trilete spores dominate while pollen grains only represent 11.5% of the total particulate organic matter. Representatives of the fern spore Klukisporites are particularly abundant and the K. variegatus acme zone, which is of biostratigraphical importance, is identified in the host strata. The abundance of K. variegatus and K. scaberis suggests a Middle Jurassic (Bajocian–Bathonian?) age for the host strata. This age designation corroborates previous stratigraphic interpretations, mainly based on plant macrofossils for this formation. The palynomorphs indicate deposition in an oxygenated environment close to the shoreline in a deltaic system. The presence of subordinate marine palynomorphs (proximate dinoflagellate cysts) is probably indicative of intermittent sea level transgression. The affinity of the palynological assemblages from the Hojedk Formation indicates a diverse parental flora of, in descending quantitative order, ferns, bryophytes and gymnosperms, the latter mainly represented by conifers and ginkgophytes. Comparisons with modern plant ecology indicate accumulation of palynomorphs under a moist warm climate during the Middle Jurassic (Bajocian–Bathonian?) time. The comparison of parental plants with previous palaeofloristic studies indicates that the Tabas Block was located in the Mid-Asian part of the Indo-European floristic province of the Northern Hemisphere.

Other coiling changes in Globoratalia Acostaensis unknown till now in Mediterranean area

In this study, all samples from Tortonian to Early Pliocene sediments of Zvernec-Vlora and Kavaja-Durres regions within Peri-Adriatic Foredeep (PAF) of Albania containing Globorotalia acostaensis were studied qualitatively and quantitatively. Based on these analyses resulted that G. acostaensis have changed coiling ratio direction during G. acostaensis and G. obliquus extremus Zone of Tortonian, differently from that known in Mediterranean area up to now. This is not a short time interval, which more exactly is from the first appearance of G. acostaensis to first appearance of G. suterae, at the upper part of G. extremus Zone. Another documented and explaining unconformity here is related with beginning of Pliocene sediments. There are at least four alienating sinistral and dextral coiling changes in G.acostaensis populations. Also in this work is given the history of the study of G acostaensis and which maybe causes that this species in Mediterranean province and especially in our country is used relatively late as zonal marker species. The main object of stratigraphers and paleontologists has been finding a successive section, with uninterrupted sedimentation, possibly for the longest geological time. Regarding to this phenomenon could be explained resulting unconformity between coiling ratio changes in Globorotalia acostaensis of the present study and other studies carried out in Mediterranean area on this occasion up to now. It is difficult to understand here the resulting unconformity during the main part of Tortonian age, which prolonged more than 2 m.y. Another resulting unconformity discovered at the Miocene/Pliocene boundary of the Kavaja-Durres regions is very significant. In these regions was discovered an earlier Pliocene sedimentation than known up to now according to resulting alternations of coiling direction of Globorotalia acostaensis prior to Pliocene Sphaeroidinellopsis Acme zone. These data are in favour of those based on the isotopie stratigraphy, which give a new definition at 5.32 M.Y. Miocene/Pliocene boundary instead of 5.1 or 5.2 M.Y. given previously based on absolute age. Coiling changes, in our case that of G. acostaensis are in response to changing climates or alternation of different cold and warm water populations resulting from changes in the boundaries between water masses as at the beginning of the Pliocene when the water masses of the Atlantic Ocean overflowed the Mediterranean area. Here is also proposed to correct the Neogene paleoclimatic curve referring, for the interval of G. acostaensis range distribution.

An Albian demise of the carbonate platform in the Manín Unit (Western Carpathians, Slovakia)

Abstract The production of platform carbonates of the Manín Unit (Manín Straits, Central Western Carpathians) belonging to the Podhorie and Manín formations and formed by remains of rudists and benthic foraminifers (Urgonian-type carbonates), was previously assumed to terminate during the Aptian. First, we show that these deposits were primarily formed on the upper slope (Podhorie Formation) and in a fore-reef environment (Manín Formation). Second, biostratigraphic data indicate that the shallow-water production persisted up to the Albian, just as it did in another succession of the Manín Unit. The Podhorie Fm contains colomiellids (Colomiella recta, C. mexicana) and calcareous dinoflagellates (Calcisphaerula innominata) that indicate the Albian age. It also contains planktonic foraminifers (Ticinella roberti, Ticinella cf. primula, Ticinella cf. madecassiana, Ticinella cf. praeticinensis) of the Albian Ticinella primula Zone. The Podhorie Formation passes upwards into peri-reefal facies of the Manín Fm where we designate the Malý Manín Member on the basis of rudists shell fragments and redeposited orbitolinids. Microfacies associations share similarities with the Urgonian-type microfacies from Mediterranean Tethys and allow us to restrict the growth and the demise of the carbonate platform. δ13C and δ18O isotopes change over a broad range of both formations: δ13C is in the range +1.03 to +4.20 ‰ V-PDB and δ18O is in the range −0.14 to −5.55 ‰ V-PDB. Although a close correlation between δ13C and δ18O indicates diagenetic overprint, a long-term increase of δ13C can indicate a gradual increase in the aragonite production and/or increasing effects of oceanic water masses in the course of the Albian, prior to the final platform drowning. Carbonate platform evolution was connected with submarine slumps and debris flows leading to redeposition and accumulation of carbonate lithoclasts and bioclastic debris on the slope. Our study confirms that the growth of carbonate platforms in the Central Western Carpathians was stopped and the platform collapsed during the Albian, in contrast to the westernmost Tethys. A hardground formed during the Late Albian is overlain by Albian - Cenomanian marls of the Butkov Formation with calcisphaerulid limestones characterized by planktonic foraminifers of the Parathalmanninella appenninica Zone and calcareous dinoflagellates of the Innominata Acme Zone.

Manual of Neogene foraminifera from off-shore Nile Delta (Egypt) and their biostratigraphic significance

The Mediterranean Nile Delta is a major target for hydrocarbon reservoirs. In the search for hydrocarbons, high-resolution biostratigraphy has long been established as high-impact and low-cost solution to face the challenges in the move towards structurally more complex and unexplored areas. To date, the biozonation of the Nile Delta is largely provided by benthic and planktonic index foraminifera. We have examined the foraminifera assemblages from NDOB-1, a borehole in the northern part of the Nile Delta. The material recovered provides unique and exceptionally well-preserved microfossil biotas that completely cover the Neogene succession (Middle Miocene to Pleistocene). This allows the establishment of an intact biozonation scheme for the Nile Delta region with reliable chronostratigraphic correlation and suitable industrial applications.The stratigraphic succession of the Nile Delta region consists of seven formations: Sidi Salim Formation, Qawasim Formation, Rosetta Formations, Abu Madi Formation, Kafr El Sheikh Formation, El Wastani Formation and Mit Ghamr Formation. Examination of the planktonic foraminifera assemblages of the NDOB-1 borehole from the deep part of the Nile Delta lead to the identification of twelve biozones: Globorotalia inflata Interval Zone, Globorotalia aemiliana Interval Zone, Globorotalia puncticulata Interval Zone, Globorotalia puncticulata- Globorotalia margaritae Concurrent Range Zone, Globorotalia margaritae Interval Zone, Sphaeroidinellopsis seminulina Acme Zone, Non-distinctive Zone, Globorotalia suterae Interval Zone, Globigerina woodi Interval Zone, Globorotalia mayeri Interval Zone, Globorotalia fohsi peripheroronda Interval Zone and Praeorbulina glomerosa Interval Zone. The biozones fully cover the time span from the Middle Miocene to the Pleistocene. The benthic foraminifera recovered allow the identification of five benthic biozones for the Pliocene and Pleistocene: Hyalinea balthica Interval Zone, Bulimina marginata Interval Zone, Bulimina aculeata Interval Zone, Gyroidinoides laevigata Interval Zone and Uvigerina rutila Interval Zone. The identified planktonic bioevents were used to calibrate the studied Neogene section with the Astronomically Tuned Neogene Time Scale (ATNTS, 2012).

Cenomanian-Turonian biostratigraphy of the Jardas Al Abid area, Al Jabal Al Akhdar, northeast Libya

The Upper Cenomanian-Turonian succession exposed at Jardas al’Abid area consists mainly of carbonates with siliciclastic intercalations. This succession is subdivided lithostratigraphically into: Qasr al’Abid (Late Cenomanian) and Al Baniyah (Late Cenomanian-Coniacian) formations. This sequence is relatively rich in macrofossil assemblages especially bivalves, gastropods, and echinoids with rare ammonites. Based on the first occurrence (FO) and last occurrence (LO) of some index species of these macrofossil groups, an integrated biostratigraphic framework has been constructed. The studied Cenomanian-Turonian sequence is subdivided biostratigraphically into three ammonite biozones; Pseudaspidoceras pseudonodosoides Total Range Zone, Choffaticeras segne Total Range Zone, and Coilopoceras requienianum Total Range Zone. Based on the rest of macrofossil assemblages other than the ammonites, eight biozones were recognized; Mecaster batnensis Total Range Zone, Ceratostreon flabellatum–Neithea dutrugei Acme Zone, Costagyra olisiponensis Acme Zone, Pycnodonte (Phygraea) vesicularis vesiculosa Acme Zone, Mytiloides labiatus Total Range Zone = Mecaster turonensis Acme Zone, Rachiosoma rectilineatum-Curvostrea rouvillei-Tylostoma (T.) globosum Assemblage Zone, Radiolites sp.-Apricardia? matheroni Total Range Zone, and Nerinea requieniana Total Range Zone. Most of the proposed biozones are recorded for the first time from Libya. The integration among these biozones as well as local and inter-regional correlation of the biozones have been discussed. The stage boundaries of the studied stratigraphic intervals are discussed, where the Cenomanian/Turonian boundary is delineated at the last occurrence (LO) of Pseudaspidoceras pseudonodosoides (Choffat), while the Turonian/Coniacian boundary is delineated arbitrary being agree with the LO of the Turonian fauna.