Quaternary dune carbonates from the Mediterranean Coast of Egypt: Petrography and diagenesis

Summary The Quaternary carbonates of the Mediterranean coast of Egypt between Alexandria and Salum appear as parallel limestone ridges rising up to 100 m above sea level. These ridges are dominated by dunal carbonates which differ not only in their primary composition but also by distinct grades of meteoric water diagenesis. Oolitic facies dominates the younger aeolianites of the first and second ridges. Bioclastic facies with abundant coralline algae, benthonic foraminifers, molluscs, echinoderms and intraclasts represents the major rock type in the older aeolianites. Features of meteoric water diagenesis include precipitation of increasing amounts of avoid-filling low Mg-calcite spar, dissolution of aragonite and stabilization of aragonite and high Mg-calcite to low Mg-calcite. Aeolianites below paleosol horizons contain abundant calcrete cements, micritized fossils and detrital grains which are commonly corroded and replaced by calcite. Three stages of progressive meteoric diagenesis are recognised in the Egyptian Quaternary aeolianites. In stage 1 minor precipitation of low Mg-calcite occurs at the grain boundaries. Stage 2 is marked by partial dissolution of aragonite, partial loss of high Mg-calcite and precipitation of low Mg-calcite in some pore spaces. In stage 3, most of the remaining pores are occluded by cementation. At the end of stage 3, Mg is removed from high Mg-calcite but some aragonite still persists. The early vadose cements are represented by miniscus, bridge and pendant cements. The phreatic cements were precipitated as bladed spar in the isopachous rims and equant spar in the intergranular and mouldic porosity. The late vadose cements are represented by micritic cements that were related to calcrete formation. Elemental behaviour during meteoric water diagenesis indicates that it leads to a gradual decrease in bulk Sr along with Na in progressively altered aeolianites. Mn distribution is controlled by the carbonate mineralogy (aragonite versus calcite) as well as the proximity of the aeolianites to the overlying paleosol horizons.     

Benthic foraminiferal associations in the Northern Bay of Safaga, Red Sea, Egypt

In the shallow-water area (0–70 m) of the Northern Bay of Safaga, 73 surface samples were studied with respect to total foraminiferal fauna. The samples cover a great variety of shallow-water environments and yielded 239 foraminiferal taxa. Based on q-mode cluster analysis, and tested by canonical discriminant analysis, the samples are grouped into 13 foraminiferal associations, each characterized by several species:

(1) Quinqueloculina mosharrafai-Borelis schlumbergeri-Brizalina simpsoni Ass.,

(2) Heterostegina depressa-Amphlstegina lessonii/bicirculata Ass.,

(3) Cibicidids-Rosalina-Amphistegina lobifera-Pseudoschlumbergerina ovata Ass.,

(4) Peneroplis planatus Ass.,

(5) Peneroplis planatus-Varidentella neostriatula Ass.,

(6) Peneroplis planatus-Coscinospira hemprichii-Varidentella neostriatula Ass.,

(7) Quinqueloculina spp. Ass.,

(8) Hauerina diversa-Sorites orbiculus Ass.,

(9) Verneuilina sp.-n Articulina pacifica-Reussella simplex Ass.,

(10) Textularia agglutinans/rugulosa-Bolivina variabilis Ass.,

(11) Textularia agglutinans-Challengerella bradyi-Elphidium jenseni/simplex Ass.,

(12) Operculina ammonoides-Adelosina laevigata-Brizalina striatula/subspathulata Ass.,

(13) Bolivina variabilis—Miliolinella-Nonion fabum-Elphidium simplex Ass.

The characteristic forms of each association are linked to specific environmental parameters and modes of life. As long as taxonomic uniformitarianism can be applied, similar associations with comparable ecological demands may also be detected in the fossil record. For comparisons with taxonomically different material the 13 associations are summarized into 4 categories each reflecting a specific type of substrate. In the fossil record these categories may be recognized by general morphological characteristics of the foraminiferal tests and by sedimentological data. The 4 substrate types are: hardground, sand (with or without seagrass and/or corals), firmground, and soft bottom.     

Coral communities and coral-bivalve associations in the northern Red Sea at Safaga,Egypt

Summary The reefs near Safaga, Egypt, are built mainly by coral species ofPorites andAcropora. These genera are in general important for the formation of coral communities and reef structures. WhileMontipora orPavona are also species rich, their mean colony size is too small for a substantial role in the build-up of carbonate mass. Yet as a host coral,Montipora is more important thanPorites; both may accommodate the pectinidPedum and certain species of mytilidLithophaga. Such associations appear to be typical for specific reef areas and to be correlated to the food supply of the bivalves. These findings can be used for an actuopaleontological interpretation of the fossil situation. In addition to the frequency of occurrence, factors such as the growth form, growth rate, skeletal density and lifespan of corals are essential in determining their share in reef construction.     

Environmental stress and diagenetic modifications in inoceramids and belemnites from the Upper Cretaceous James Ross Basin, Antarctica

Summary New petrographic and isotopic data from inoceramid bivalve shells and belemnite rostra from the lower Campanian and belemnite rostra from the mid-upper Maastrichtian of the Marambio Group, James Ross Basin, Antarctica are presented. Most of the inoceramid data were processed from shell fragments of the large formAntarcticeramus rabotensis (Crame and Luther) at the stratigraphic level marking the extinction of the inoceramids in the James Ross Basin (uppermost early Campanian-basal late Campanian). Standard transmitted light microscopy and cathodoluminescence (CL) studies in thin sections ofA. rabotensis show clear evidence of environmental stress, which is reflected as marked growth breaks in the shell banding of this large inoceramid bivalve. At Redonda Point, CL and the mean oxygen isotopic value (δ¹⁸O=-3.11‰ 3 (PDB); n=11; t°=25.4°C) indicate a varied degree of diagenetic modification, but without any evidence of neomorphism along the prismatic microstructures. Early Campanian belemnite rostra are much less diagenetically modified (at the Brandy Bay section; and the Santa Marta section; δ¹⁸O=-0.50‰ (PDB); n=5; t°=14.0°C and 3 δ¹⁸O=-0.94‰ (PDB); n=21; t°=15.8°C) and are non luminescent 3 except for localized, organic-rich bands. The mean oxygen isotopic value for mid-late Maastrichtian belemnite rostra (at the Seymour Island section; δ¹⁸O=-0.11‰ 3 (PDB); n=5; t°=12.5°C) indicates a substantial drop in the sea-water paleotemperature, suggesting a causal relationship between the early extinction of the inoceramid bivalves in high latitudes of the Southern Hemisphere and the falling sea-water temperature.     

Feeding and growth of the pearl oyster Pinctada margaritifera (L.) in Dongonab Bay,Red Sea

Plankton samples and gut contents of P. margaritifera were analysed monthly from April 1972 to March 1973. Coscinodiscus sp. was the most ingested food by pearl oysters of all ages. However, food variety increased as the oyster grew older. Experiments confirmed the absence of food selectivity in P. margaritifera. Unlike the young ones, the adult showed reduced growth during summer (July–September), which coincides with its spawning season.     

Marine molluscs and fish as biomarkers of pollution stress in littoral regions of the Red Sea, Mediterranean Sea and North Sea

The intensive development of industry and urban structures along the seashores of the world, as well as the immense increase in marine transportation and other activities, has resulted in the deposition of thousands of new chemicals and organic compounds, endangering the existence of organisms and ecosystems. The conventional single biomarker methods used in ecological assessment studies cannot provide an adequate base for environmental health assessment, management and sustainability planning. The present study uses a set of novel biochemical, physiological, cytogenetic and morphological methods to characterize the state of health of selected molluscs and fish along the shores of the German North Sea, as well as the Israeli Mediterranean and Red Sea. The methods include measurement of activity of multixenobiotic resistance-mediated transporter (MXRtr) and the system of active transport of organic anions (SATOA) as indicators of antixenobiotic defence; glutathione S-transferase (GST) activity as an indicator of biotransformation of xenobiotics; DNA unwinding as a marker of genotoxicity; micronucleus test for clastogenicity; levels of phagocytosis for immunotoxicity; cholinesterase (ChE) activity and level of catecholamines as indicators of neurotoxicity; permeability of external epithelia to anionic hydrophilic probe, intralysosomal accumulation of cationic amphiphilic probe and activity of non-specific esterases as indicators of cell/tissue viability. Complete histopathological examination was used for diagnostics of environmental pathology. The obtained data show that the activity of the defensive pumps, MXRtr and SATOA in the studied organisms was significantly higher in the surface epithelia of molluscs from a polluted site than that of the same species from control, unpolluted stations, providing clear evidence of response to stress. Enhanced frequency of DNA lesions (alkaline and acidic DNA unwinding) and micronucleus-containing cells was significantly higher in samples from polluted sites in comparison to those from the clean sites that exhibited genotoxic and clastogenic activity of the pollutants. In all the studied molluscs a negative correlation was found between the MXRtr levels of activity and the frequency of micronucleus-containing hemocytes. The expression of this was in accordance with the level of pollution. The complete histopathological examination demonstrates significantly higher frequencies of pathological alterations in organs of animals from polluted sites. A strong negative correlation was found between the frequency of these alterations and MXRtr activity in the same specimens. In addition to these parameters, a decrease in the viability was noted in molluscs from the polluted sites, but ChE activities remained similar at most sites. The methods applied in our study unmasked numerous early cryptic responses and negative alterations of health in populations of marine biota sampled from the polluted sites. This demonstrates that genotoxic, clastogenic and pathogenic xenobiotics are present and act in the studied sites and this knowledge can provide a reliable base for consideration for sustainable development. Received: 2 March 1999 / Received in revised form: 2 August 1999 / Accepted: 3 August 1999     

Composition and distribution of benthic isopod (Crustacea,Malacostraca) families off the Victoria-Land Coast (Ross Sea,Antarctica)

The benthic fauna off the Victoria-Land-Coast, Ross Sea (Antarctica) was investigated during the 19th Italica expedition in February 2004. Samples were taken along a latitudinal transect from Cape Adare down to Terra Nova Bay at water depths ranging from 84 to 515 m. A Rauschert dredge was used at 18 stations to collect epi- and infaunal macrobenthos. 9,494 specimens of Isopoda were collected, representing 19 families. Desmosomatidae were the most abundant family (35,297 ind/1,000 m²), followed by Paramunnidae (23,973 ind/1,000 m²). Paramunnidae was the most frequent taxon and was collected at all stations, in contrast to the Desmosomatidae, which did not occur at any station off Cape Adare.     

Reproduction and developmental pathways of Red Sea Xeniidae (Octocorallia,Alcyonacea)

This work on Red Sea alcyonaceans describes the reproductive patterns of 21 xeniid species. Gonochorism is the commonest sexual mode but simultaneous hermaphroditism was recorded in 4 species and brooding of planulae was observed in 15 species. The reproductive patterns of Xenia umbellata and Heteroxenia fuscescens were examined. X. umbellata exhibits seasonal spermatogenesis, continuous oogenesis and a 7 month period of planulation each year. H. fuscescens has continuous gametogenesis, and planulation occurs throughout the year, lacking any lunar pattern. The prolonged breeding season of H. fuscescens reflects intrapopulation asynchrony in larval development and subsequent maturation. Xeniids possess structurally similar gonads, but adopt diverse reproductive and developmental pathways.     

Platform environments, microfacies and systems tracts of the upper Cenomanian-lower Santonian of Sinai, Egypt

Summary Factors controlling grain composition and depositional environments of upper Cenomanian—Santonian limestones of Sinai are discussed. The mainly shallow-water, inner-platform setting investigated is subdivided into five major facies belts, each represented by several microfacies types (MFTs). Their lateral distribution patterns and their composition underline aclear relation between depositional environment and platform position. The facies belts include sandstones and quartzose packstones of siliciclastic shorefaces, mudstones and bioclastic wackestones of restricted lagoons, shallow-subtidal packstones with diverse benthic foraminifera and calcareous algae, bioclastic and/or oolitic grainstones of inner-platform shoals, and wackestones of deep open-marine environments. The microfacies distribution patterns of the Cenomanian-Santonian strata are evaluated with respect to local and regional large-scale environmental changes. While protected shallow-subtidal environments with only subordinate ooids and oncoids prevail during the late Cenomanian, high-energy oolithic shoals and carbonate sands occur locally during the middle and late Turonian. They were probably related to a change of the platform morphology and a reorganisation of the platform after a late Cenomanian drowning. In the Coniacian-Santonian, the lack of ooids, oncoids, and the decrease of calcareous algae versus an increase in siliciclastics indicate a shift to lower water temperature and to a more humid climate. Especially in the Turonian, the interplay between sea-level changes, accommodation, hydrodynamics, and siliciclastic input is reflected by lithofacies and biofacies interrelation-ships that are elaborated within individual systems tracts. In particular, increasing accommodation intensified circulation and wave-agitation and controlled the distribution of high-energy environments of the middle and upper Turonian trans-gressive systems tracts. During highstands protected innerplatform environments prevailed.     

Cretaceous and Cenozoic non-marine deposits of the Northern South Yellow Sea Basin, offshore western Korea: palynostratigraphy and palaeoenvironments

Palynological analyses of two wells (Haema-1 and Kachi-1) located in two sub-basins of the Northern South Yellow Sea Basin have been carried out in order to establish a palynostratigraphic breakdown of the sedimentary succession and to determine environments of deposition. Seven assemblage zones and two assemblage subzones have been erected on the basis of frequency variations in, and occurrences of, biostratigraphically significant palynomorphs as follows: Classopollis-Ephedripites Assemblage Zone (AZ): Barremian-Albian; Alisporites-Aquilapollenites-Penetetrapites AZ, which is subdivided into an Alisporites-Rugubivesiculites Assemblage Subzone: Cenomanian-Lower Maastrichtian, and an Aquilapollenites-Penetetrapites Assemblage Subzone: Upper Maastrichtian; Momipites-Coryluspollenites AZ: Paleocene; Caryapollenites-Inaperturopollenites AZ: Lower-Middle Eocene; Quercoidites-Pinuspollenites AZ: Upper Eocene; Liquidambarpollenites-Fupingopollenites-Magnastriatites AZ: Lower-Middle Miocene; Graminidites-Persicarioipollis AZ: Pliocene. The depositional environments represented by the well sections are considered to have been generally fluvio-lacustrine, and the climate to have varied between semi-arid and wet, and subtropical and warm temperate, except during the Late Eocene and Pliocene when a cool-temperate climate prevailed. Six stages in the development of the sub-basins are recognised. These are: (1) initial stage of rift or pull-apart basin-formation during the Late Jurassic?-Cretaceous; (2) subsidence from the Paleocene to Middle Eocene; (3) alternation of uplift and subsidence in the Late Eocene; (4) synrift inversion and erosion through the Oligocene; (5) uplift during the Early Miocene; and (6) widespread subsidence from the Middle Miocene onwards apart from during the Early Pliocene when the region was subjected to uplift once more.     

Fluoride,Some Selected Elements,Lipids, and Protein in the Muscle and Liver Tissues of Five Fish Species along the Egyptian Mediterranean Sea Coast

Fish is a vital, healthy source of animal protein and vitamins. This study was oriented to estimate fluoride, some selected elements, lipids, and protein concentrations in fish. Five fish species were collected from the Egyptian Mediterranean Sea coast during April 2007. Variable content of fluoride, calcium, magnesium, sulphate, phosphorus, lipids, and protein were determined in muscle and liver of fish samples and yielded average values in fish muscle of 11.0 ± 2.0 μg/g, 6.5 ± 3.8 mg/g, 100.2 ± 39.3 mg/g, 4.4 ± 6.3 mg/g, 2.4 ± 0.5 mg/g, 6.0 ± 2.2 mg/l, and 2.6 ± 1.0 g% wet wt, respectively. Special attention was given to fluoride because of its hazardous classification. Interestingly, the hazard index values of fluoride were less than 1 for all collected fish species. Additionally, the daily fluoride exposure was generally below the nutrient reference values for Australian and New Zealand populations. Accordingly, there is little human health risk from the selected fish species due to consumption of fluoride-contaminated fish.     

Lithostratigraphy and facies development of upper cretaceous carbonates in east central Sinai,Egypt

Summary The Upper Cretaceous exposures in east central Sinai are represented by carbonate-dominated successions interbedding few sandstone, chert, shale and marl horizons. The recognised rock units are correlated with their counterparts commonly used in the Gulf of Suez region and central Sinai including from base to top: the Raha Formation, Abu Qada Formation, Wata Formation, Matulla Formation and the Sudr Chalk. Twelve limestone microfacies are encountered and are categorised as mudstones (pelmicrite and ostracod micrite), wackestones (pelagic biomicrite and foraminiferal biomicrite), grainstones (foraminiferal biopelsparite and oosparite), boundstones (bindstone and framestone), floatstones (coated-grained biomicrudite, rudist biomicrudite and shelly biomicrudite) and rudstones (shelly biosparudite). The dolostone microfacies include fine-medium crystalline ostracod dolostones and shelly dolostones. These microfacies have been compared with the Standard Microfacies Types and their depositional environments are discussed. The encountered litho- and biofacies suggest that the Cenomanian shallow transgressive sea had covered east central Sinai as far south as the Dahab region. By the advent of the Turonian, open marine subtidal conditions prevailed. This was followed by transitional conditions with shoals and tidal bars in the Late Turonian pointing to a regressive phase more pronounced at the southern localities. The rocks of the Matulla Formation were deposited in an oscillating environment of shallow subtidal to intertidal conditions during Coniacian-Santonian. In the Late Santonian and during most of the Campanian-Maastrichtian, sedimentation was influenced by open marine conditions with low sedimentation rates; local shallow subtidal regressive events occurred.     

Fossil Flowers and Associated Plant Fossils from the Kamikitaba Locality (Ashizawa Formation, Futaba Group, Lower Coniacian, Upper Cretaceous) of Northeast Japan

in situ spores, and megaspores also document the presence of Selaginellaceae and Schizaeaceae. Received 8 February 1999/ Accepted in revised form 7 April 1999     

Pliocene facies and fossil contents of Qaret El-Muluk formation at Wadi El-Natrun depression, Western Desert, Egypt

Summary A sequence of late Pliocene sediments (Qaret El-Muluk Formation) covers large areas within Wadi El-Natrun depression; at the western periphery of the Nile Delta. The exposed sequence is composed of friable sands. mudstones, shales and minor limestones with combined total thickness of approximately 50 m. The fossil content consists of fresh and brackish water elements; charophytes, ostracods, gastropods, oysters and benthonic foraminifera. Planktonic forams which suggest marine influence have been also recorded. Terrestrial and aquatic continental vertebrate fauna includes mammals, reptiles, fish and aves. Several subtypes of ichthyoliths have been discovered in this study. Both lithological and paleontological data testify to a depositional environment which belongs to a marginal region where fluvial and marine deposition meet in shallow brackish lagoons. The sediments display changes from channelled fluvial sands to deltaic interbedded sands and mudstones to lagoonal shales and limestones to lacustrine chara limestones. Vertical stacking of facies is indicative of a series of transgressive-regressive events. The transgression brought shallow lagoonal conditions to the area. The transgressions were incomplete due to high rate of fluvial input. The lagoon dried up intermittently and calcretes and red brown soils were formed. Each regression is indicated by river generated clastic influx. During periods of active fluvial input, fluvial sediments prograded lagoonward. The clastic material was probably a mixture of reworked detritus from older sediments. An admixture of first cycle material from the basement rocks of the Red Sea hills cannot be ruled out. The diversity of provenance argues for several channels of a large river which existed during the late Pliocene.     

Reproductive biology of a Red Sea goby, Silhouettea aegyptia, and a Mediterranean goby, Pomatoschistus marmoratus, in Lake Timsah, Suez Canal

The reproductive biology of the Red Sea goby Silhouettea aegyptia , and Mediterranean Pomatoschistus marmoratus , has been studied in Lake Timsah, Suez Canal. Male: female sex ratio was 1: 1 7 in S. aegyptia and 1: 2 7 in P. marmoratus . Size at first maturity was 20 mm ( s.l. ) in S. aegyptia and 24 mm in P. marmoratus . The breeding season of S. aegyptia extended from March to September with most gonadal activity in May, whereas in P. marmoratus , it stretched from. November until the following April with a peak in February. Hepatosomatic index for both species exhibited monthly fluctuations and an inverse correlation with gonadosomatic index was evident. Oocyte size-frequency distribution indicated several modes at 400, 600 and 800 μm during the breeding season. Fecundity of S. aegyptia ranged from 152 to 782 with an average of 468 eggs, whereas in P. marmoratus it varied between 293 and 1300 with an average of 603 eggs. Fecundity was related curvilinearly to fish length, body weight and ovary weight. Recruitment of young fish to the adult populations occurred in late July and early August for S. aegyptia and during March for P. marmoratus . Life history pattern indicated that both species of gobies are successful colonists of Lake Timsah, Suez Canal.     

Integrated stratigraphy and palaeoenvironment of the Cenomanian-Lower Turonian (Upper Cretaceous) of northern Westphalia, North Germany

Summary The present study provides an integrated stratigraphy of the Lower Cenomanian-Lower Turonian of the northwestern Münsterland Basin, Westphalia. This is important to establish a standard section allowing an interregional correlation as well as an interpretation of single environmental conditions, their changes through time and their geographical extent. Numerous sections have been investigated in northern Westphalia, in addition to data from other profiles in North Germany. Macrofossils and thin-sections have been sampled, stable isotope and gamma ray data have been obtained from a part of the sections. Investigation of the sedimentary sequence is based on a analysis of events. Many events are diachronous, whereas others are difficult to define and do not show a wide geographic distribution. For ecological or sedimentological reasons, correlation is not possible. The discussion of events leads to a compound picture of the evolution of the depositional sequence, allowing the reconstruction of palaeo-environmental changes. Sea-level changes and their influence on the fauna is discussed. During maximal sea-level rising, macrofossils occur more frequently for ecological reasons, however, some macrofossil accumulations are lag deposits. Some biostratigraphical problems find their origin in a tectonic separation leading to different habitats. The local tectonics was caused by the intial phase of transpression of the Osning Zone, that can be traced down to the Lower Cenomanian. A correlation of the Cenomanian-Turonian Boundary Event (CTBE) in Westphalia (Lengerich), Colorado (USA) and England (Eastbourne), is possible due to very dense sampling of carbon-isotopes (δ¹³C). In Westphalia, definition of the stage boundary is possible by correlation of carbon isotope curves only. A sequence from the upper Middle Cenomanian, up to the lower Upper Cenomanian, is investigated concerning the controlling factors of biogenic sedimentation. The cyclicity of lithology is investigated by Fast Fourier Trans-formation. It can be shown that sedimentation is forced by orbital cycles, mainly by the precession cycle of the Milankovitch band (P1 and P2, 18 500 and 22 300 years, respectively). This confirms the primary origin of the marlstone-limestone couplets that are obvious in the field. Calculation of sedimentation rates is based on these data. There is a high variability of sedimentation rates, maybe due to a strong variation of productivity in this epicontinental environment. Dedicated to the memory of Jost Wiedmann (1931–1993)     

Flexistipes sinusarabici,a novel genus and species of eubacteria occurring in the Atlantis II Deep brines of the Red Sea

Four isolates of a gram-negative flexible bacterium have been obtained from brine water samples of the Atlantis II Deep of the Red Sea at a depth of 2000 m. One isolate (MAS 10) was studied in detail. Cells are nonmotile, flexible rods, measuring about 0.3 m in width and 5 to 50 m in length. The new organisms are heterotrophs growing anaerobically on yeast extract, meat extract, peptone, tryptone, and, less efficiently, on acetate and casamino acids. Growth occurs between 30% and 53°C at pH 6 to 8 in the presence of at least 3% NaCl. The shortest doubling time is 8.5 h under optimal growth conditions. Cells are sensitive to the antibiotics penicillin, ampicillin, vancomycin, and streptomycin, but resistant to tetracyclin and rifamipicin. The GC-content of the DNA is 39 mol%. Based on their 16S rRNA the new isolates group with the general cluster of eubacterial phyla. Since they show no specific relationship to any of them, a new genus is described, which is named Flexistipes, the flexible stick. Type species is Flexistipes sinusarabici strain MAS 10 (DSM 4947).