Open Shelf Research Articles

Benthic foraminifera from the Albian shallow-marine limestones in the Geyik Dağı area (Central Taurides), southern Turkey

AbstractCretaceous carbonates in the Geyik Dağı area (Central Taurides, southern Turkey) are represented by two successions with different paleoenvironmental settings: open shelf to slope succession of Cenomanian to Danian age and inner platform succession of Albian to Maastrichtian age, which is interrupted by a post-Cenomanian disconformity. Outcropped lowermost part of the platform-type one is composed of rudistid limestones corresponding to the Urgonian-type carbonates and belongs to the Geyik Dağı Unit (=Anamas-Akseki Carbonate Platform). It contains a rich assemblage of larger benthic foraminifera including orbitolinid, chrysalidinid, cuneolinid, nezzazatid, and miliolid taxa, which has been illustrated and documented here for the first time from the upper Albian of the Tauride Carbonate Platform. The occurrence of such a diversified foraminiferal fauna indicates a prominent high diversity that took place in the Tauride Carbonate Platform during the late Albian time, which corresponds to a major emersion period in some parts of the platform.

Remarkable multicuspid teeth in a new elusive skate (Chondrichthyes, Rajiformes) from the Mediterranean Pliocene

Here we report on four highly peculiar skate teeth from Arcille and Certaldo, two Pliocene localities of Tuscany (central Italy). While being attributable to Rajiformes and somewhat reminiscent of Dipturus and Rostroraja, these specimens display an unusual multicuspid tooth design that does not match any extinct or extant skate taxon known to date. The studied teeth are thus referred to a new genus and species of Rajiformes, Nebriimimus wardi gen. et sp. nov., which is here tentatively assigned to the family Rajidae. Based on pronounced morphological similarities between the rather large-sized teeth of the latter and those of extant nurse sharks, we hypothesise that N. wardi might have been capable of actively foraging upon relatively large food items compared to other rays. This extinct skate species was likely not a common component of the Pliocene Tuscan marine vertebrate assemblages. The palaeoenvironmental scenarios that N. wardi inhabited were marginal-marine and open shelf settings characterised by tropical climate conditions. As N. wardi is currently known only from lower to mid-Pliocene deposits of the Mediterranean Basin, it is tempting to speculate that its speciation dates back to an earliest Pliocene phase of diversification that also contributed to the emergence of the Mediterranean endemic stock of extant skate species.

Sampling nearshore Infaunal ‘weeds’ rather than ‘trees’: Does this orthodoxy undervalue importance of sedimentary biomes?

This study compares species composition, abundance, biomass, and several other factors by which sedentary megafaunal and macrofaunal assemblages at depths between 14 m and 55 m on the Hueneme Shelf in southern California, USA, can be characterized. It details fundamental differences between these assemblages in this study area and demonstrates how little we know about a diverse range of attributes that are important in describing and evaluating infaunal assemblages. It provides strong support for a recent claim that: “The soft-sediment seafloor of the open continental shelf is among the least-known biomes on Earth, despite its high diversity and importance to fisheries and biogeochemical cycling” (Tomašových and Kidwell, 2017).Basic and applied research after the 1950s transformed infaunal ecology from a discipline focused primarily on long-lived sedentary megafauna (analogous to ‘trees’ on land) into a field concentrating on opportunistic or ephemeral macrofauna (analogous to ‘weeds’ on land). Based on findings of this study, macrofaunal assemblages play a subordinate role in ecosystem dynamics. Most research in recent decades has overlooked contributions by sedentary megafauna. This focus leads to a poor understanding of the dynamics of these widespread ecosystems, severely undervalues their ecological importance and production, underestimates impacts of anthropogenic activities on unconsolidated sediments as well as the duration of recovery trajectories following disturbances.Sedentary megafaunal and macrofaunal assemblages were quite different in virtually all aspects assessed during this analysis. Although macrofauna in this study had far greater species richness and were far more abundant than sedentary megafauna, conservative estimates for megafaunal biomass and secondary production indicate these organisms contribute substantially more energy to higher trophic levels than macrofauna. In addition, the megafaunal assemblages are characterized by many influential ‘ecosystem engineers’. Consequently, the differences in numbers of species and individuals are irrelevant with regard to determining value to the ecosystem. Megafauna in this area also exhibited more sensitivity in environmental factors. They live substantially longer than macrofauna, likely leading to greater stability in megafaunal assemblages. These differences indicate that current approaches focusing on macrofauna severely undervalue infaunal resources and contributions to higher trophic levels. They imply that studies of megafaunal assemblages should provide considerably greater insight into ecosystem dynamics and secondary production than macrofaunal assemblages and would have greater power to predict or assess environmental degradation or change, and document or predict recovery trajectories.

Signals of combined chromium–cadmium isotopes in basin waters of the Early Cambrian – Results from the Maoshi and Zhijin sections, Yangtze Platform, South China

The combination of authigenic chromium and cadmium stable isotopes in marine sedimentary archives enables reconstruction of the redox conditions and levels of primary productivity in past oceans and basins. The Ediacaran to Cambrian Nanhua Basin (Yangtze Platform, South China) and its sedimentary sequences have been studied intensively in the past with respect to investigating the effects of post-Snowball Earth glaciations on the oxygenation of Earth's atmosphere, and intimately related, on the consequences of climate changes on the evolution of the ocean environment and of life during the Precambrian-Cambrian transition. Following recent propositions of using cadmium isotopes as a novel proxy for reconstructing the extent of primary productivity in paleooceans, we here present results from a combined cadmium (Cd)‑chromium (Cr) isotope study on metalliferous black shale, black shale and phosphorite sediments deposited during the Early Cambrian Niutitang Formation at the Maoshi and Zhijin sections. Results point toward strongly oxidized and highly productive surface water layers in the Nanhua Basin during this period. The samples have strongly positively fractionated δ114Cd and δ53Cr values up to +0.6‰ and + 1.4‰, respectively, similar to such values from carbonaceous sediments in modern oceans. The association of Cd with sulfides in the sediments, together with high Cd/TOC ratios particularly in the metalliferous black shales, implies a sulfide-controlled enrichment of Cd under restricted euxinic conditions. The lower Cd/TOC values in phosphorites and barren black shales and negatively fractionated δ114Cd values down to −0.33‰ point to less effective precipitation of Cd under more suboxic conditions as likely prevailing in an open shallow shelf. The Cr content in the sediments is mostly close to average shale, and the δ53Cr values are little fractionated in the 0–0.2‰ range, corroborated by flat shale-like rare earth element + yttrium (REE + Y) patterns. However, some metal-rich shale samples have clearly authigenic Cr isotope signatures with up to +1.4‰ δ53Cr, and the authigenic Cr component in the phosphorite samples is around 1‰ δ53Cr, indicating oxic surface waters. The latter sediments also depict seawater-like, middle REE enriched REE + Y patterns with distinct negative Ce and positive Y anomalies indicative of an oxygenated surface water layer, and with positive Eu anomalies which they likely received during phosphatogenesis in the euxinic bottom water environment. In accord with previous studies reporting on extreme trace metal enrichments (Mo, Ni, V, Hg, etc.) in these Early Cambrian sediments, our Cd and Cr isotope signatures favor a scenario of a strongly stratified basin in which high primary productivity thrived in an oxidized surface water layer, potentially as a result of increased nutrient supply from a strongly weathering continental hinterland in the aftermath of the last Snowball Earth glaciations in the Ediacaran.

Petrographical and microfacies study of Sinjar formation in Bazyan anticline, Sulaimaniyah region (Northern Iraq)

Purpose. The work studies Sinjar formation (upper Paleocene lower Eocene) within the Bazyan anticline in the Sulaimaniyah region (northeastern Iraq). The facies analysis is based on the petrographic study of limestone deposits and is essential to identify their nature. The sediments that formed Sinjar formation have a high content of skeletal granules which include a small amount of red algae and residues of unicellular organisms-foraminifera. Methodology. The method of work included two main aspects: field study and laboratory work. The first part included the field description of the rocky excavation and modeling of 10 rocks samples from it within the Bazyan section. As for the second main aspect, it included the preparation of 10 slides for petrographic study of Sinjar Formation rocks followed by a facial analysis of these deposits. Findings. Micro facial analysis showed that the sequences of Sinjar formation consist of three main facies. The wacky limestone facies bears benthic foraminifera. The facies of compact limestone bears the benthic foraminifera and red algae while the compact wacky limestone facies bears the fossils. Originality. Wacky limestone facies bearing benthic foraminifera, compacted limestone facies bearing benthic foraminifera and red algae, and wacky limestone facies bearing benthic foraminifera were selected and studied. Thus, according to the facial analysis, Sinjar formation was deposited within the open shelf before the formation of the main deposit. Practical value. Samples of rocks were obtained from the Bazyan anticline for further production of slides in order to study the facies of this anticline, which allowed showing its lithostratigraphic column.

Early-Middle Jurassic stepwise deepening in the transitional facies belt between the Adriatic Carbonte Platform Basement and Neo-Tethys open shelf in northeastern Montenegro evidenced by new ammonoid data from the early Late Pliensbachian (Lavinianum Zone)

New ammonoid data prove an early Late Pliensbachian deepening event above the ?Late Hettangian-Sinemurian shallow-subtidal gray-reddish micro-oncoidal-foraminifera grainstone facies and the ?early Pliensbachian deeper-marine micro-oncoidal-crinoidal-ammonoid wacke- to packstone facies. Based on the presence of Fuciniceras lavinianum (Fucini), Lytoceras ovimontanum Geyer and Arieticeratinae gen. indet. from a hardground above the deeper-water micro-oncoidal limestones in the Mihajlovici section (north - eastern Montenegro) a Late Pliensbachian to early Toarcian condensation horizon is proven. The Middle Toarcian ammonoid-bearing horizon also yielded species not known from previous studies: Calliphylloceras capitanii (cATuLLo), Harpoceras subplanatum (oPPeL) and Furloceras aff. chelussii (PAriScH & ViALe), also described in the present paper. These new data prove a stepwise deepening of the depositional area during the early and the Middle Jurassic reflected in detail in four sedimentary members: 1) ?Late Hettangian to Sine - murian/?earliest Pliensbachian open-marine shallow subtital micro-oncoidal limestones; 2) ?early to Late Pliensbachian open-marine condensed limestones with few micro-oncoids and more open-marine influence; 3) Toarcian open-marine condensed red limestones with hardgrounds; and 4) condensed red nodular Bositra Limestone. These four members are separated by hard - rounds representing stratigraphic gaps in deposition. The stepwise deepening during the early-Middle Jurassic follows the general trend of deposition as known in the whole Western Tethys realm above the Late Triassic Dachstein carbonate Platform.

The Kimmeridgian of the south-western margin of the Holy Cross Mts., central Poland: stratigraphy and facies development. Part I. From deep-neritic sponge megafacies to shallow water carbonates

The stratigraphical interval of the Kimmeridgian between the Bimammatum and the Hypselocylum zones in the SW margin of the Holy Cross Mts. shows a transition from the open shelf deep-neritic sponge megafacies to the shallow-water carbonate platform, including its development and decline. The uniform progradation of the shallow-water carbonate platform occurred at the end of the Planula Chron. Development of the shallow-water carbonate platform was controlled by climatic and tectonic factors. The former induced by orbital cyclicity resulted in changes of sea-level, revealed i.a. by the incoming of open-marine ammonite faunas, the latter were related to the synsedimentary activity of faults which resulted in contrasted facies changes. The episodically occurring strong influx of siliciclastic material was at least partly controlled by the tectonic activity. The newly elaborated formal lithostratigraphic subdivision takes into account the facies development of the succession in relation to climatically and tectonically induced changes. Such is e.g. the Małogoszcz Oolite Formation, corresponding to a single 100-kyr eccentricity cycle from the late Platynota Chron to the earliest Hypselocyclum Chron, bordered from the base and top by two transgressive climatically-controlled levels. The final stage of the shallow-water platform development at the end of the Hypselocyclum Chron was marked by the successive limitation of restricted environments, and the appearance of more open-marine conditions related to tectonic subsidence of the area of study. Comparison between the carbonate platform development of the Holy Cross Mts. in central Poland, and the coeval shallow-water carbonates of the Jura Mts. in northern Switzerland and south-eastern France provides an opportunity to consider similarities in the successions which can be attributed to the climatically-controlled sedimentary cyclicity and/or the wide-ranged tectonic phenomena. The palaeontological part of the study gives comments on the classification and phylogeny of ammonites of the families Ataxioceratidae and Aulacostephanidae.

Microbial community shifts along an estuarine to open ocean continuum

The water bodies along a continuum from estuaries to open ocean display significant changes in their physical, chemical and biological characteristics. In the current study, we report the influence of such changes on the abundance and community structure of bacteria and archaea in a continuum from Cochin Estuary, in the southwest coast of India, to the open ocean of Arabian Sea. The bacterial and archaeal abundances were in the range of 104 to 106 and 103 to 105 cells ml−1 respectively in all the stations and showed a clear dependence on nutrients. The bacterial abundance decreased with depth in the open ocean, whereas the archaea showed a similar reduction at both shelf and open ocean stations. The α- Proteobacteria (35 %) and Cyanobacteria (23 %) were dominant in the estuary. More than 70 % of the community of bacteria on the shelf and in the open ocean were similar. The α- and γ-Proteobacteria contributed 37 & 27 % of the OTUs in the clone library of shelf and 20 & 29 % in the open ocean. The archaeal community structure in the open ocean and shelf were similar (90 %) composed mostly of Nitrosopumilaceae (70%–75%), while they were highly diverse in the estuary. In short, our study shows that the archaea are more diverse in the estuary compared to shelf and open ocean, while bacteria are equally diverse in all ecosystems.

Late Artinskian Nautiloids of the Shakh-Tau Reef (Bashkortostan)

A nautiloid assemblage is described for the first time from the Upper Artinskian of the Shakh-Tau shikhan, including 14 species of 12 genera of coiled and uncoiled taxa. Most species identified in this assemblage were originally described by V.N. Shimansky (Shimansky, 1954; Ruzhencev and Shimansky, 1954) from several Sakmarian and Artinskian open shelf sections of the South Urals. Previously, only two species of Pseudorthocerida were reported from Shakh-Tau, while no coiled taxa had been recorded from the region of the Sterlitamak shikhans. In its taxonomic diversity, the Shakh-Tau assemblage is comparable to the synchronous Zhil-Tau (=Gil-Tau) fauna of the South Urals.

Variable predator–prey relations in zooplankton overwintering in Subarctic fjords

Zooplankton predator–prey relations in northern Norwegian fjords are highly variable in time and space, and the mechanisms driving this variability are still poorly understood. Replicate Juday net sampling in October and February from 1983 to 2005, which included five repeated tows from bottom to surface, was conducted in Saltfjord and Mistfjord, northern Norway. The time-series provided evidence of in situ variability in species abundance, as well as seasonal and interannual changes in standing stock abundance. The shallow sill of one fjord caused accumulation of coastal water in the fjord’s basin, while the other fjord’s deeper sill selected denser water of Atlantic origin from the same open shelf habitat. The selective advection caused differences in the immigration of species recruiting to the fjords’ specific overwintering communities of zooplankton. Statistical analyses of the cumulated replicate data indicated significant in situ variability in the spatial density of species. Cases with an abundance of carnivores relating positively to other species probably resulted from the carnivores’ attraction to patches with concentrations of prey. Interspecific negative density relations likely indicated either predator avoidance or substantial trophic activity during the sampling. During years of high abundance, some wintering stocks of carnivores evidently reduced the local stocks of overwintering prey. We conclude that predator–prey interactions and stock variability in Subarctic fjords result from complex bio-geophysical interactions that occur on the scales of local habitats and basin-scale population systems.

Influence of Poultry Manure on Growth and Fruit Yield of Selected Pepper Species and Their Qualities after Storage in Various Structures

The production of pepper is low due to decrease in fertility of soil and inadequate storage structures. The study was aimed at evaluating the growth, yield and storage qualities of selected pepper varieties as influenced by poultry manure and storage structures in Ibadan, Nigeria. A field experiment was carried out at Department of Agronomy, University of Ibadan between November, 2017 and April, 2018 growing season. Two varieties of pepper (Capsicum annum and Capsicum frutescens) were used, with four treatments consisting of different rates of poultry manure. Controls of 0 g of poultry manure (T1), 12.5 g (T2), 25 g (T3) and 37.5 g (T4) were laid out in a complete randomised design and replicated four times. Storage experiment was carried out in the Department and at Nigeria Stored Products Research Institute (NSPRI), Ibadan in June, 2018. The storage experiment comprised of four treatments with ambient condition (open shelf), wet basket, Evaporative Coolant Structure (ECS/Pot-in-pot), and plastic crates used as storage structures, laid out in a completely randomised design and replicated three times. The physical parameters obtained in days in storage (DIS) included weight loss (%), firmness, freshness, among others. Data observed were subjected to analysis of variance (ANOVA) and means separated using least significant difference (LSD) at p>0.05. The result obtained showed that pepper growth was enhanced using Capsicum frutescens under 25 g poultry manure application rate which resulted to superior pepper yield. The combination of pot-in-pot with sawdust as storage structures enhanced the storage qualities of pepper fruits within the two weeks of storage. Although, the different manure treatments had no significant effect on the postharvest quality of pepper, the ECS can be effectively used in the storage of pepper fruits in order to improve postharvest quality, extend shelf life and enhance affordability of the commodity at all seasons.

Sedimentology of mixed siliciclastic-carbonate system in a structurally constrained Paleogene basin: Eocene Musawa Formation in Eastern Oman Mountains

The Middle Eocene sedimentary succession in Abat Basin contains a thick mixed siliciclastic and carbonate sequence belonging to the upper member of the Musawa Formation. Over 300 m thick deltaic sediments of the Bartonian to Priabonian upper member of the Musawa Formation show two main facies successions over ten km distance, grading from a proximal delta-plain to a distal delta-front succession. Four major lithofacies associations based on their depositional significance are identified in the basin, namely the conglomerate, sandstone, mudstone, and carbonate. Each of these lithofacies associations is further divided into several individual lithofacies based on their depositional characteristics. The lithofacies association assemblage represents fluvially-dominated deltaic sediments that accumulated as a local siliciclastic feature in a carbonate dominated tropical environment. The conglomerate and sandstone lithofacies associations were deposited by channels and shoreface processes, whereas coastal processes in delta-plain setting deposited mudstone lithofacies association (including coal). The carbonate lithofacies association was deposited in an open marine shelf conditions during transgressive events associated with highstands of sea level and delta-lobe switching. The occurrence of thick siliciclastic sediments is interpreted as the result of activation of the North Ja'alan Fault resulting in a transtensional basin during the Middle to Late Eocene.

Seawater 87Sr/86Sr ratios along continental margins: Patterns and processes in open and restricted shelf domains

To better constrain the Sr isotope budget in marginal domains without any fluvial inputs, we analyzed the chemical composition and 87Sr/86Sr ratio of waters and shells from four locations: two coastal lagoons, one hemipelagic platform and one open marine shelf. Our results highlight homogeneous 87Sr/86Sr ratios typical of oligotrophic oceanic waters (OOW) (i.e., 0.709172 ± 0.000023) in the Pacific Tatakoto atoll and along a Mediterranean shore to offshore transect (~25 km off Banyuls-sur-Mer, BSM). This attests that oceanic inputs from oligotrophic areas remain the main Sr source in open shelf areas compared with submarine groundwater discharges (SGD) or particulate dissolution influences. In BSM, only foreshore data are more radiogenic, possibly due to rainwater mixing, local groundwater springs or more efficient particle dissolution in the intertidal zone. In restricted areas, we report variable 87Sr/86Sr ratios between the Salses-Leucate (France) and Oualidia (Morocco) lagoons. The first one has homogeneous 87Sr/86Sr ratio typical of OOW except close to SGD. In Oualidia, 87Sr/86Sr ratios decrease by 1.2 × 10−3 from OOW values close to the Atlantic inlet to progressively less radiogenic ones upstream within the interior of the lagoon. These differences depend on several factors including the leaky, restricted or choked morphology of lagoons modulating the oceanic Sr inputs, but also SGD fluxes whose 87Sr/86Sr ratios and Sr concentrations are highly variable according to the nature of rocks leached in karstic aquifer. In Oualidia, the low 87Sr/86Sr ratios correspond to high Sr concentrations (up to 150 μmol·l−1) issued from the dissolution of Mesozoic evaporites, leading to SGD fluxes accounting for 60% of the local Sr budget. Through data compilation, we show that similar 87Sr/86Sr gradients and processes prevail at the whole Mediterranean scale. Finally, we postulate that high coastal water retention times can also account for anomalous coastal 87Sr/86Sr ratios and that the combination of water mass restriction, SGD, bioadsorption and early diagenetic processes could decrease seawater Sr concentrations in some marginal areas.

Contrasting marine carbonate systems in two fjords in British Columbia, Canada: Seawater buffering capacity and the response to anthropogenic CO2 invasion.

The carbonate system in two contrasting fjords, Rivers Inlet and Bute Inlet, on the coast of British Columbia, Canada, was evaluated to characterize the mechanisms driving carbonate chemistry dynamics and assess the impact of anthropogenic carbon. Differences in the character of deep water exchange between these fjords were inferred from their degree of exposure to continental shelf water and their salinity relationships with total alkalinity and total dissolved inorganic carbon, which determined seawater buffering capacity. Seawater buffering capacity differed between fjords and resulted in distinct carbonate system characteristics with implications on calcium carbonate saturation states and sensitivity to increasing anthropogenic carbon inputs. Saturation states of both aragonite and calcite mineral phases of calcium carbonate were seasonally at or below saturation throughout the entire water column in Bute Inlet, while only aragonite was seasonally under-saturated in portions of the water column in Rivers Inlet. The mean annual saturation states of aragonite in Rivers Inlet and calcite in Bute Inlet deep water layers have declined to below saturation within the last several decades due to anthropogenic carbon accumulation, and similar declines to undersaturation are projected in their surface layers as anthropogenic carbon continues to accumulate. This study demonstrates that the degree of fjord water exposure to open shelf water influences the uptake and sensitivity to anthropogenic carbon through processes affecting seawater buffering capacity, and that reduced uptake but greater sensitivity occurs where distance to ocean source waters and freshwater dilution are greater.

MICROFACIES AND DEPOSITIONAL ANALYSIS OF THE MISHRIF FORMATION IN SELECTED WELLS OF RATAWI OILFIELD, SOUTHERN IRAQ

This paper includes studying the distribution of microfacies, diagenetic processes and depositional basin of the Mishrif Formation in selected wells of Ratawi oilfield (Ratawi-2 and Ratawi-5), southern Iraq. More than 200 thin sections of samples were examined of the above-mentioned wells. The Mishrif Formation is divided into three major microfacies: lime mudstone, wackestone, and packstone, which are deposited in sub-basinal, lagoonal open shelf margin, and, shoal environments. Benthonic foraminifera, planktonic, Echinodermata and algae represent the fossils in the Mishrif Formation. Dolomite and calcite are the main minerals components of formation. Seven diagenetic processes were recognized in the Mishrif Formation, showed positive and destructive effects on the reservoir quality; dissolution and neomorphism (recrystallization) had highly positive effects through creating and improving porosity and permeability, which led to improving reservoir quality. Cementation, micritization, and compaction have destructive effects, through reducing porosity and permeability and led to reducing reservoir quality. Other processes such as, dolomitization, authigenic minerals (pyrite) did not have strong effects on reservoir quality. Based on the genetic classification of the porosity, most of the porosity within the Mishrif Formation in this field was formed by diagenesis processes, in which the predominant pore types are vuggy, intraparticle, fractured, and moldic. Analysis of microfacies showed that there are three main facies and eight secondary facies in the Mishrif Formation. The longitudinal section of the depositional environments showed, that Mishrif Formation deposited in the sub-basinal, lagoonal, open shelf margin, and shoal environments depending on fossils observed in a number of microfacies.

Invertebrate epibionts on Ordovician conulariids from the Prague Basin (Czech Republic, Bohemia)

Approximately 4% of just over 5000 conulariids from ten Ordovician formations in the Prague Basin (Czech Republic) exhibit invertebrate epibionts and/or attachment scars. The commonest epibionts are craniid brachiopods followed by bryozoans and edrioasteroids, which are invariably articulated. Less abundant are monoplacophorans, Sphenothallus sp., ?Lichenocrinus sp., and an indeterminate invertebrate. Epibionts occur on Anaconularia anomala, Archaeoconularia, Conulariella sp., and Pseudoconularia grandissima, though predominantly on A. anomala and Archaeoconularia from open shelf deposits in the Upper Ordovician Letná and Zahořany formations, in which conulariids are substantially more abundant than in other formations. Epibionts on a particular conulariid belong to a single species or up to three species and major taxa. Except for monoplacophorans, epibionts occur on the external surface of the conulariids, in some cases with brachiopods, bryozoans, or edrioasteroids present on all four faces. Brachiopods and edrioasteroids present on all four faces show little variation between the faces in their size range. Also, brachiopods show apparent random trending of the antero-posterior axis, while edrioasteroids on some specimens of A. anomala and Archaeoconularia are preferentially centered on or near the facial midline. On schott-bearing specimens of A. anomala exhibiting brachiopods and/or edrioasteroids, these and other epibionts are absent on the schott. Bryozoans on some A. anomala and Archaeoconularia cover portions of all four faces and corners, and on two specimens of A. anomala the schott, too, is encrusted. A similar case involving edrioasteroids on Archaeoconularia sp. from the Upper Ordovician Upper Tiouririne Formation of Morocco is documented.These results highlight the importance of Ordovician conulariids as biological substrates, especially in Perunica and South Polar Gondwana, and indicate that encrustation occurred both on live individuals and on dead ones. The corners and midlines influenced the settlement and subsequent growth of brachiopods and edrioasteroids, and conulariids bearing these epibionts were buried catastrophically.

Cambrian stratigraphy (Series 2 to Miaolingian) of the El Sahuaral area in central Sonora, Mexico: Biostratigraphic implications

The lower and middle Cambrian strata exposed in the state of Sonora, Mexico, consists of sequences of quartzarenite, limestone, shale and dolomite exposed in several localities, mainly in the northwestern and central regions of Sonora. Approximately 800 m interval of Cambrian marine sedimentary rocks are exposed in the El Sahuaral area, a new Cambrian locality in central Sonora. The sedimentary succession of these marine facies is divided into five lithostratigraphic units previously documented in Mexico: Proveedora, Buelna, Cerro Prieto, El Gavilán and El Tren formations. The Proveedora Formation is the oldest sequence of Cambrian strata in the region and consists of a 168 m thick sequence of bioturbated, fine-grained quartzarenite. The Buelna Formation conformably overlies the Proveedora Formation in the El Sahuaral and adjacent areas and consists of 70 m of interbedded limestone and shale, with abundant fragments of olenellid trilobites from either the Bristolia mohavensis or Bristolia insolens zones (Series 2, Stage 4). The overlying Cerro Prieto Formation is composed of a 70 m thick sequence of recrystallized oolitic limestone with possible fragments of Amecephalus arrojosensis, suggesting the Amecephalus arrojosensis Zone (uppermost Series 2, Stage 4). The El Gavilán Formation conformably overlies the Cerro Prieto Formation with a thickness of 225 m; it is composed of interbedded limestone and shale deposited in a marine open shelf environment, with abundant fauna of the upper Ehmaniella Zone (Altiocculus Subzone), Ptychagnostus praecurrens - Ptychagnostus gibbus Zone (Miaolingian Series, Wuliuan Stage). The El Tren Formation, reported by the first time in central Sonora, conformably overlies the El Gavilán Formation and consists of 250 m thick sequence of dolomitic limestone with unidentified trilobite fragments. The Cambrian deposits of central Sonora present marine facies that vary from the littoral zone to open marine shelf, accumulated in the western part of the North American craton and contains an abundant and diverse biota comprised by cyanobacteria, poriferans, brachiopods, trilobites, and echinoderms.

Risk reduction in a cancer chemotherapy production unit: Contribution of an automated drug dispensing system.

The purpose of our study was to evaluate the contribution of an automated drug dispensing system in securing cancer chemotherapy production process at the pharmacy of the National Institute of Oncology in Rabat. The failure modes and effects analysis method was applied to the chemotherapy production process in two phases: Phase 1, using an open shelf for storage then phase 2, using an automated drug dispensing system. The failure modes were defined and their criticality indexes was calculated on the basis of the likelihood of occurrence, the potential severity for the patients and/or the impact on the process and the detection probability. The criticality indexes of the two phases were prioritized and compared. We identified 35 failure modes for phase 1 and 37 for phase 2. The sum of criticality indexes was 5957 and 4586, respectively, for phase 1 and phase 2, corresponding to a criticality reduction of -23%. The greatest improvements concerned that the needed drug is missing during the picking, storage of potential expired drugs, and double compounding. Our study highlighted the contribution of automated drug dispensing system in risk minimization. The use of automated drug dispensing system is a part of security improvement in chemotherapy production unit.

Diversity and paleoenvironmental implications of an elasmobranch assemblage from the Oligocene-Miocene boundary of Ecuador.

The occurrence and diversity of elasmobranchs from the Oligocene–Miocene boundary from Tropical America is poorly known in comparison with the paleodiversity from younger Neogene intervals of the region. Here we describe a new elasmobranch assemblage from the rich fossil site of Montañita-Olón (Dos Bocas Formation, Santa Elena, Ecuador), where other vertebrates have already been described: for example, sea turtles and cetaceans. We report a total of 27 elasmobranch taxa, 19 of which are new fossil records for Ecuador, 10 new records for the Central Eastern Pacific and four new records for South America. Additionally, in order to reconstruct the environment where these marine remains were deposited, we performed abundance, paleobathymetric and habitat preference analyses, concluding that they were likely deposited in an outer neritic (open shelf) environment. The study of Oligocene and early Miocene marine elasmobranchs faunas in Tropical America is key to addressing the issues in the evolutionary history of this group.

Sediment controls dynamic behavior of a Cordilleran Ice Stream at the Last Glacial Maximum

The uncertain response of marine terminating outlet glaciers to climate change at time scales beyond short-term observation limits models of future sea level rise. At temperate tidewater margins, abundant subglacial meltwater forms morainal banks (marine shoals) or ice-contact deltas that reduce water depth, stabilizing grounding lines and slowing or reversing glacial retreat. Here we present a radiocarbon-dated record from Integrated Ocean Drilling Program (IODP) Site U1421 that tracks the terminus of the largest Alaskan Cordilleran Ice Sheet outlet glacier during Last Glacial Maximum climate transitions. Sedimentation rates, ice-rafted debris, and microfossil and biogeochemical proxies, show repeated abrupt collapses and slow advances typical of the tidewater glacier cycle observed in modern systems. When global sea level rise exceeded the local rate of bank building, the cycle of readvances stopped leading to irreversible retreat. These results support theory that suggests sediment dynamics can control tidewater terminus position on an open shelf under temperate conditions delaying climate-driven retreat.