Presence-absence species/sample matrix for the measured sections at the area of Maghara, North Sinai, Egypt

As age-diagnostic fossils are rare in the Middle to Upper Jurassic sedimentary succession of Gebel Maghara, North Sinai, Egypt, and in order to ensure maximal stratigraphic resolution, chronostratigraphic boundaries were determined based on quantitative biostratigraphy. A data matrix comprising 231 macrofaunal taxa in 93 samples from four sections has been processed with the Unitary Association (UA) Method. This led to construction of a sequence of 29 UAs (maximal sets of actually or virtually coexisting taxa), which have been grouped into 14 laterally reproducible association zones. The UA method allowed an in-depth analysis of the stratigraphically conflicting taxa, enabled the biostratigraphic subdivision of the studied interval, and also provided stratigraphic correlation among the measured sections and with the Tethyan ammonite zones.

Chemical profiles in sediment and basalt at DSDP Hole 74-525A

Forty sediment and four basement basalt samples from DSDP Hole 525A, Leg 74, as well as nine basalt samples from southern and offshore Brazil, were subjected to instrumental neutron activation analysis. Thirty-two major, minor, and trace elements were determined. The downcore element concentration profiles and regression analyses show that the rare earth elements (REE) are present in significant amounts in both the carbonate and noncarbonate phases in sediments; Sr is concentrated in the carbonate phase, and most of the other elements determined exist mainly in the noncarbonate phase. The calculated partition coefficients of the REE between the carbonate phase and the free ion concentrations in seawater are high and increase with decreasing REE ionic radii from 3.9 x 10**6 for La to 15 x 10**6 for Lu. Calculations show that the lanthanide concentrations in South Atlantic seawater have not been changed significantly over the past 70 Ma. The Ce anomaly observed in the carbonate phase is a redox indicator of ancient seawater. Study of the Ce anomaly reveals that seawater was anoxic over the Walvis Ridge during the late Campanian. As the gap between South America and West Africa widened and the Walvis Ridge subsided from late Campanian to late Paleocene times, the water circulation of the South Atlantic improved and achieved oxidation conditions about 54 Ma that are similar to present seawater redox conditions in the world oceans. The chemical compositions of the basement rocks correspond to alkalic basalts, not mid-ocean ridge basalts (MORBs). The results add more evidence to support the hypothesis that the Walvis Ridge was formed by a series of volcanos moving over a "hot spot" near the Mid-Atlantic Ridge. From the chemical composition and REE pattern, one 112 Ma old basalt on the Brazilian continental shelf has been identified as an early stage MORB. To date, this is the oldest oceanic tholeiite recovered from the South Atlantic. This direct evidence indicates that the continental split between South America and Africa commenced > 112 Ma.

Oceanography during TYDEMAN cruise DCM (DeepChlorMax) to the Equatorial Atlantic

The cruise with RV Tydeman was devoted to study permanently stratified plankton systems in the (sub)tropical ocean, which are characterised by a deep chlorophyll peak between 80 and 150 m. To minimise lateral effects by horizontal transport of nutrients and organic matter from river outflow and upwelling regions, stations were selected in the middle of the North Atlantic Ocean between the continents of America and Africa. (5 - 35° N and 50 - 15° W). Here the vertical distributions of light and nutrients control the abundance and growth of autotrophic algae in the thermically stratified water column. This phytoplankton is numerically dominated by the prokaryotic picoplankters Synechococcus spp. and Prochlorococcus spp., which are smaller than 2 ?m. The productivity of the 100 to 150 m deep euphotic zone can be high, because a high heterotrophic/autotrophic biomass ratio induces a rapid regeneration of nutrients and inorganic carbon. Primary grazers are mainly micro-organisms such as heterotrophic nannoflagellates and ciliates, which feed on the small algae and on bacteria. Heterotrophic bacteria can outnumber the autotrophic algae, because their number is related to the substrate pools of dissolved and particulate dead organic matter. These DOC and detritus pools reach equilibrium at a concentration, where the rate of their production (proportional to algal biomass) equals their mineralisation and sinking rate (proportional to the concentration and weight of POC and detritus). At a relatively low value of the weight-specific loss rates, the equilibrium concentration of these carbon pools and their load of bacteria can be high. The bacterial productivity is proportional to the mineralisation rate, which in a steady state can never be higher than the rate of primary production. Hence the ratio in turnover rate of bacteria and autotrophs tends to be reciprocally proportional to their biomass ratio.

Geochemistry of Miocene Alborán Basin volcanism

We present new major and trace element and O-Sr-Nd-isotope data for igneous rocks from the western Mediterranean Alborán Sea, collected during the METEOR 51/1 cruise, and for high-grade schists and gneisses from the continental Alborán basement, drilled during the Ocean Drilling Programme (ODP Leg 161, Site 976). The geochemical data allow a detailed examination of crustal and mantle processes involved in the petrogenesis of the lavas and for the first time reveal a zonation of the Miocene Alborán Sea volcanism: (1) a keel-shaped area of LREE-depleted (mainly tholeiitic series) lavas in the central Alborán Sea, generated by high degrees of partial melting of a depleted mantle source and involving hydrous fluids from subducted marine sediments, that is surrounded by (2) a horseshoe-shaped zone with LREE-enriched (mainly calc-alkaline series) lavas subparallel to the arcuate Betic-Gibraltar-Rif mountain belt. We propose that the geochemical zonation of the Miocene Alborán Basin volcanism results from eastward subduction of Tethys oceanic lithosphere coupled with increasing lithospheric thickness between the central Alborán Sea and the continental margins of Iberia and Africa.

Long-term chemical characterization of aerosols at CVAO from 2007 to 2011

The first long-term aerosol sampling and chemical characterization results from measurements at the Cape Verde Atmospheric Observatory (CVAO) on the island of São Vicente are presented and are discussed with respect to air mass origin and seasonal trends. In total 671 samples were collected using a high-volume PM10 sampler on quartz fiber filters from January 2007 to December 2011. The samples were analyzed for their aerosol chemical composition, including their ionic and organic constituents. Back trajectory analyses showed that the aerosol at CVAO was strongly influenced by emissions from Europe and Africa, with the latter often responsible for high mineral dust loading. Sea salt and mineral dust dominated the aerosol mass and made up in total about 80% of the aerosol mass. The 5-year PM10 mean was 47.1 ± 55.5 µg/m**2, while the mineral dust and sea salt means were 27.9 ± 48.7 and 11.1 ± 5.5 µg/m**2, respectively. Non-sea-salt (nss) sulfate made up 62% of the total sulfate and originated from both long-range transport from Africa or Europe and marine sources. Strong seasonal variation was observed for the aerosol components. While nitrate showed no clear seasonal variation with an annual mean of 1.1 ± 0.6 µg/m**3, the aerosol mass, OC (organic carbon) and EC (elemental carbon), showed strong winter maxima due to strong influence of African air mass inflow. Additionally during summer, elevated concentrations of OM were observed originating from marine emissions. A summer maximum was observed for non-sea-salt sulfate and was connected to periods when air mass inflow was predominantly of marine origin, indicating that marine biogenic emissions were a significant source. Ammonium showed a distinct maximum in spring and coincided with ocean surface water chlorophyll a concentrations. Good correlations were also observed between nss-sulfate and oxalate during the summer and winter seasons, indicating a likely photochemical in-cloud processing of the marine and anthropogenic precursors of these species. High temporal variability was observed in both chloride and bromide depletion, differing significantly within the seasons, air mass history and Saharan dust concentration. Chloride (bromide) depletion varied from 8.8 ± 8.5% (62 ± 42%) in Saharan-dust-dominated air mass to 30 ± 12% (87 ± 11%) in polluted Europe air masses. During summer, bromide depletion often reached 100% in marine as well as in polluted continental samples. In addition to the influence of the aerosol acidic components, photochemistry was one of the main drivers of halogenide depletion during the summer; while during dust events, displacement reaction with nitric acid was found to be the dominant mechanism. Positive matrix factorization (PMF) analysis identified three major aerosol sources: sea salt, aged sea salt and long-range transport. The ionic budget was dominated by the first two of these factors, while the long-range transport factor could only account for about 14% of the total observed ionic mass.