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Integrated steelworks produce steel from iron-ore. Co-produced are vast amounts of slags in the Blast Furnace process (~200-250 kg slag/ton of metal) and Basic Oxygen Furnace (BOF) process (~100 kg slag/ton of steel). Whereas BF-slag is in high demand for cement use, BOF-slag addition to cement doesn’t create synergy, despite mineralogical similarity. BOF slag mineralogy can be predicted using thermochemical modelling for the multicomponent system CMAFfSP, using FactSage, and petrological observations of BOF slag confirm phenocrysts of Magnesio-Wuestite (Liquidus-phase) followed by alpha-C2S, in a groundmass of co-crystalizing Wuestite, Srebrodolskite (C4AF), C2S and lime. Incorporation of minor constituents (Ti, V, Cr) occurs in Wuestite (Cr) and C2S (V) and C4AF (V, Ti), but cannot be predicted for lack of solid solution models. Cr and V can cause leaching concerns for slag applications. Studying hydration reactions on finely ground BOF slag indicates that hydrogarnet, hydrotalcite, portlandite and CSH-gel tend to form as product and that all primary slag phases contribute in the reaction. The leaching of Vanadium is pH-controlled during C2S dissolution. Application of BOF slag as secondary raw material requires adequate characterization. Grinding BOF slag to cement-fineness can produce a high-strength binder, however, requiring the aid of specific additives. C=CaO; M=MgO; A=Al2O3; F=Fe2O3; f=FeO; S=SiO2; P=P2O5; C2S=Ca2SiO4

Measuring temperature and salinity profiles in the world’s oceans is crucial to understanding oceandynamics and its influence on the heat budget, the water cycle, the marine environment and on our climate.Since 1983 the German research vessel and icebreaker Polarstern has been the platform of numerous CTD (conductivity,temperature, depth instrument) deployments in the Arctic and the Antarctic. We report on a uniquedata collection spanning 33 years of polar CTD data. In total 131 data sets (1 data set per cruise leg) containingdata from 10 063 CTD casts are now freely available at doi:10.1594/PANGAEA.860066. During this longperiod five CTD types with different characteristics and accuracies have been used. Therefore the instrumentsand processing procedures (sensor calibration, data validation, etc.) are described in detail. This compilation isspecial not only with regard to the quantity but also the quality of the data – the latter indicated for each dataset using defined quality codes. The complete data collection includes a number of repeated sections for whichthe quality code can be used to investigate and evaluate long-term changes. Beginning with 2010, the salinitymeasurements presented here are of the highest quality possible in this field owing to the introduction of theOPTIMARE Precision Salinometer.

Pb-210 dating of two metal-polluted organic sedimentcores obtained near a former pyrometallurgical zinc smelter in Lommel, Belgiumhave been used to reconstruct atmospheric lead deposition rates during the20th century. Independent knowledge concerning historical pollutionevents and 137Cs fall-out profiles has allowed a criticalevaluation of the CRS, CIC and CF-CS models for the 210Pb ageinterpretation. Resulting ages for the three models suggest that, in this case,the CIC model gives the most accurate interpretation of historical pollutionevents and atmospheric lead fall-out. The 210Pbwater-sediment flux was estimated at 141–1158Bq·m−2·yr−1 for one site and62–106 Bq·m−2·yr−1 at theother site, during the last century. The large difference illustrates thatsediment focusing was important on a small spatial scale (10 m).The direction of focusing correlates with the predominant wind direction.Maximum atmospheric lead deposition rates were found to be 1.63 ± 0.59g·m−2·yr−1 around 1968 AD,which is 2 orders of magnitude larger than the Belgian average in 1980 AD, and5 orders larger than Holocene atmospheric lead deposition.

The atmospheric pollution history of a former Belgian Zn-smelter complex is preserved in organic sediments of a nearby peat bog pool. The stratigraphy of trace metals, Pb-isotope ratios and mineralogy indicate extreme heavy metal pollution in recent sediments. In the pollutant trend, extremes coincide with maxima in 20th century metal production, minima during major war conflicts and the final shutdown of the smelter. Peak pollution concentrations measure up to 4.7 wt.% Zn, 1.1 wt.% Pb and 0.1 wt.% Cd, which correspond to calculated atmospheric deposition rates of 9.0, 1.6 and 0.16 g m(-2) yr(-1), respectively. 206Pb/207Pb isotope ratios show higher values in the polluted interval (1.135-1.162) relative to local geogenic values deeper down-core (1.194-1.215). Within the polluted interval, three significantly different 208Pb/206Pb plateaus are recognized and suggested to indicate changes in the origins of processed ores. Microprobe analyses on sediment thin sections show extensive in situ FeS2 and ZnS precipitation, which suggests that anoxic processes are responsible for the immobilization of the atmospheric metal inputs. The occurrence of oxidized smelter dusts in an independent surface soil sample indicates a rapid diagenetic transformation of metal oxides into sulfides. Morphology and chemical characteristics allow the distinction between smelter related and diagenetic mineral deposits, and give evidence for dust from open-air ore repositories, as well as smelter operation without dust filters.

Multi-channel confocal micro-Raman spectroscopy was used to investigate the structure of K2Si4O9 and hydrous NaAlSi3O8 (H-Ab) glasses at high pressure (⩽15.2 GPa) and room temperature, and at ambient pressure and high temperature (⩽1246 K). The high-pressure and high-temperature data have provided insights into the structures of these glasses. For K2Si4O9 glass, the observed increase in the relative intensity of the 592 cm−1D2 ‘defects’ band above 3.8 GPa and above Tg at 1 atm indicate that Si—O—Si linkages with small bond angles, similar to those found in three-membered rings, contribute to the D2 band. Pressure and temperature dependences of the Raman bands of K2Si4O9 glass in the 900–1200 cm−1 region indicate that a significant amount of five- and sixfold coordinated silicon atoms occurs only at P⩾7.7 GPa. Raman spectra of H-Ab glass were measured in both the low-wavenumber (100–1200 cm−1) and the O–H stretching (2700–3800 cm−1) regions. At 1 atm, the spectrum of H-Ab glass shows a broad band near 900 cm−1 and a doublet consisting of broad bands near 1000 and 1100 cm−1. The pressure and temperature dependences of the intensities of the 900 and 1000 cm−1 bands indicate that the 900, 1000 and 1100 cm−1 bands of H-Ab glass result from distorted TO4 (T=Si or Al) tetrahedra, in which the usual triple degeneracy of the antisymmetric stretching mode is lifted. In the O–H stretching region of the H-Ab glass, the presence of numerous hydrated species (e.g. OH−, H3O+and H2O) is indicated by the splitting of the broad 3548 cm−1asymmetric band into two bands at 2.1 GPa with peaks at 3481 and 3562 cm−1, and by their respective shifts in the negative and positive directions with increasing pressure.

Recent experimental work has shown that the homogenization of elemental concentrations can be much slower than that of isotopic ratios when there are strong concentration gradients in SiO_2 and Al_2O_3. The ramifications of this result for magma homogenization and other petrological problems related to diffusion are significant. We report here a comparison of experimental profiles of elemental concentrations and isotopic fractions of K and Ca in rhyolite-andesite (large concentration gradients) and rhyolite-rhyolite (small concentration gradients) melt couples. When the concentration profile and the isotopic profile of the same element in a single couple are compared, the former is much shorter than the latter in the rhyolite-andesite couple, consistent with other recent studies. However, the lengths of both concentration and isotopic profiles are similar in the rhyolite-rhyolite couple. Therefore, diffusion of an element or oxide may be decoupled from or coupled with isotopic ‘diffusion’, depending on whether large concentration gradients of major components are present. When the two couples are compared, the intrinsic effective binary diffusivities obtained from isotopic profiles are similar for each element in the two couples, whereas the effective binary diffusivity of K obtained from the concentration profile in the rhyolite-rhyolite couple is 37 times that in the rhyolite-andesite couple. Therefore, isotopic homogenization is roughly independent of elemental homogenization and the presence of SiO_2, Al_2O_3, and other concentration gradients, whereas elemental homogenization is strongly affected by concentration gradients. Our experimental data (isotopic and concentration profiles including uphill diffusion profiles) can be modeled quantitatively to a good approximation using a modified effective binary diffusion model in which the flux of a component is assumed to be proportional to its activity gradient instead of its concentration gradient. Therefore, the multicomponent diffusion effect in the silicate systems of our experiments seems to be largely due to contributions of non-ideal mixing to the cross-terms of the diffusivity matrix.

We have performed time series experiments for periods ranging from 3 min to 44 h on the interaction of granite melt and partially molten basalt at 920°C and 10 kbar, in the presence of 5 wt.% water. With time, the assemblage of the basalt domain changes from predominantly amphibole+plagioclase to clinopyroxene+garnet; the melt fraction increases from ˜2⋅5 to 40%; and between the two domains, the melt compositions progressively equilibrate. Initially in each run, melts of the basalt domain have uniform plateau concentrations for SiO_2, Al_2O_3, CaO, MgO, and FeO because the activities of these components are regulated by the mineral assemblage, but at advanced stages of reaction, no such control is evident. We have derived analytical expressions to describe and simulate the diffusion profiles. The concentration profiles for SiO_2, Al_2O_3, CaO, and Na_2O in the granite, emanating from the basalt–granite interface, have been used to estimate effective diffusivities. The values from the shorter runs are compared with those of the experiment of longest duration for which we assumed finite couples in our calculations. In the diffusion calculations for K2O the difference in melt fraction between the two domains is accounted for. The resulting values (in cm^2/s) are: D_(Na_2O)=6 × 10^(–7), D_(K_2O)=3 × 10^(–7), D_(MgO)=9 × 10^(–8), D_(CaO)=(4–6) × 10^(–8), and D_(SiO_2) and D_(Al_2O_3)=(3–0⋅6) × 10^(–8). They are in reasonable agreement with values from other studies. On the basis of our experiments we calculate that mafic enclaves of magmatic origin should equilibrate to a large degree with their host magma in slowly cooling non-convecting granitic plutons. Enclaves approaching complete re-equilibration retain distinctly higher modal amounts of mafic minerals. They do not compositionally resemble binary magma mixtures, but are more like host magma with accumulated crystals. We show that the modal differences between enclave and host are indicative of the temperature of homogenization and that, in principle, this temperature can be deduced from equilibrium phase diagrams.

We present crystallization experiments on Archean Nuk gneiss from West Greenland, and relate these to conditions for early continental crustal genesis. The studied composition is a trondhjemite from a voluminous felsic intrusive phase dated at 2,800-3,000 m.y. In a detailed set of experiments at 10 kbar, the liquidus mineralogy is observed to change with increasing water content from plagioclase above 1000°C and 7 wt % water. Water saturation of the melt occurs with 10.5 wt % water at 800°C. Mafic liquidus minerals at 15 kbar differ from those at 10 kbar in that garnet replaces pyroxene, and that epidote replaces hornblende below 690°C at >13 wt % water and at water saturation (15.5 wt %). Garnet crystallization is never observed at pressures below 13 kbar. Using additional experiments at 12.5, 13, and 17 kbar, the liquidus phase variation for trondhjemite with water is accurately defined between 8-18 kb...

A morphologically complex igneous basement was penetrated at Leg 125 Site 786 beneath approximately 100 m of Eocene-Pleistocene sediments at 31°52.45 'N, 141°13.59'E in a 3082-m water depth. The site is located on the forearc basement high (FBH) of the Izu-Bonin (Ogasawara) Arc. In the broadest terms, the sequence in Hole 786B consists of a basal sheeted dike complex, heavily mineralized in places, with overlying pillow lavas giving way to a complex and repeated sequence of interlayered volcanic breccias and lava flows with some thin sedimentary intervals. The sequence has been further cut by dikes or sills, particularly of high-Ca and intermediate-Ca boninite, and is locally strongly sheared by faulting. The whole basement has been covered with middle Eocene-early Pleistocene sediments. A monomict breccia forms the shallowest portion of Hole 786B and a polymict breccia having Mn-oxide-rich clast coatings and matrix forms the deepest part of Hole 786A (-100-160 mbsf). The basement is tectonized in some places, and a mineralized stockwork is present in the deepest part of Hole 786B. A wide variety of rock types form this basement, ranging from mafic to silicic in character and including high-, intermediate-, and low-Ca boninites, intermediate- and low-Ca bronzite andesites, andesite, dacite, and rhyolite groups. Intragroup and intergroup relationships are complicated in detail, and several different upper mantle source(s) probably were involved. A significant role for orthopyroxene-clinopyroxene-plagioclase fractionation is indicated in the mafic-intermediate groups, and the most probable complementary cumulates should be noritic gabbros. Many overall similarities but some subtle differences are noted between the igneous basement at Site 786 and the subaerial outcrops of the FBH to the south in the type boninite locality of Chichijima. Both suites were derived by hydrous melting of a relatively shallow, refractory (harzburgitic) upper mantle source. These Bonin forearc basement rocks are similar in many respects to those of Eocene-Oligocene age now forming the forearc of the Marianas at Leg 60 Site 458 and on Guam. In sharp distinction, the geochemistry of the Eocene-Pleistocene ash sequences overlying the Bonin FBH must have been derived from a very different upper mantle source, implying considerable across-strike differences in sub-arc mantle composition

K-Ar whole-rock ages have been obtained for 30 samples from Sites 782 and 786, Ocean Drilling Program Leg 125 in the Izu-Bonin (Ogasawara) forearc region. They form a trimodal spread of ages between 9 Ma and 44 Ma and are, with a few exceptions, consistent with the inferred lithostratigraphy. The ages have been interpreted in terms of at least two distinct episodes of magmatic and/or hydrothermal activity. A group of ten samples, including the lava flows, gave an isochron age of 41.3 ± 0.5 Ma (middle-late Eocene). This is thought to represent the age of the principal magmatic development of the volcanic forearc basement, and is comparable to published ages on equivalent rocks from other parts of the forearc basement high (e.g., the Ogasawara Islands). It may be significant that this age is slightly younger than the timing of major plate reorganization in the Western Pacific at about 43 Ma. This was followed by a minor episode of intrusive magmatism at 34.6 ±0.7 Ma (early Oligocene) which appears to have reset the ages of some of the earlier units. This event probably corresponds to the initiation of rifting of the "proto-arc" to form the Parece Vela Basin. Boninitic samples were erupted during both episodes of magmatism, the earlier being of low-Ca boninite type and the later being of medium and high-Ca types. It is also possible that a third episode of intrusive magmatism affected the Izu-Bonin forearc region at both Sites 782 and 786 at about 17 Ma. This would be consistent with magmatic activity elsewhere in the region during the Miocene, associated with the end of active spreading in the Parece Vela Basin and the start of arc activity in the West Mariana Ridge

Eleven glasses recovered from Holes 786A and 786B were fresh enough for volatile analysis by infrared spectroscopy. The compositions of these glasses range from boninitic to rhyolitic. The glasses from the boninites contain 1.4 to 1.7 wt% H_2O, while the rhyolitic glasses contain 2 to 6 wt% H_2O, and all glasses have less than 30 to 40 ppm CO_2. The highest H_2O contents are probably the result of seawater alteration. The unaltered dacitic to rhyolitic glasses were probably quenched at low pressures corresponding to depths of 0-700 m below the seafloor, also corresponding to the depths of collection of these samples, although the water depths may have been different between the Eocene and the present. The lower boninitic H_2O contents in vesicular glasses suggest shallow quenching on the seafloor.

Holes drilled into the volcanic and ultrabasic basement of the Izu-Ogasawara and Mariana forearc terranes during Leg 125 provide data on some of the earliest lithosphere created after the start of Eocene subduction in the Western Pacific. The volcanic basement contains three boninite series and one tholeiite series. (1) Eocene low-Ca boninite and low-Ca bronzite andesite pillow lavas and dikes dominate the lowermost part of the deep crustal section through the outer-arc high at Site 786. (2) Eocene intermediate-Ca boninite and its fractionation products (bronzite andesite, andesite, dacite, and rhyolite) make up the main part of the boninitic edifice at Site 786. (3) Early Oligocene intermediate-Ca to high-Ca boninite sills or dikes intrude the edifice and perhaps feed an uppermost breccia unit at Site 786. (4) Eocene or Early Oligocene tholeiitic andesite, dacite, and rhyolite form the uppermost part of the outer-arc high at Site 782. All four groups can be explained by remelting above a subduction zone of oceanic mantle lithosphere that has been depleted by its previous episode of partial melting at an ocean ridge. We estimate that the average boninite source had lost 10-15 wt% of melt at the ridge before undergoing further melting (5-10%) shortly after subduction started. The composition of the harzburgite (

Eocene-Oligocene volcanic rocks drilled at Site 786 in the Izu-Bonin forearc cover a wide range of compositions from primitive boninites to highly evolved rhyolites. K-Ar dating reveals at least two distinct episodes of magmatism; one at 41 Ma and a later one at 35 Ma. The early episode produced low-Ca boninites and bronzite andesites that form an oceanic basement of pillow lavas and composite intrusive sheets, overlain by flows and intrusive sheets of intermediate-Ca boninites and bronzite-andesites and a fractionated series of andesites, dacites, and rhyolites. The later episode produced high-Ca boninites and intermediate-Ca boninites, exclusively as intrusive sheets.

Twenty-six samples representing the wide range of lithologies (low- and intermediate-Ca boninites and bronzite andesites, high-Ca boninites, basaltic andesites-rhyolites) drilled during Leg 125 at Sites 782 and 786 on the Izu-Bonin outer-arc high have been analyzed for Sr, Nd, and Pb isotopes. Nd-Sr isotope covariations show that most samples follow a trend parallel to a line from Pacific MORB mantle (PMM) to Pacific Volcanogenic sediment (PVS) but displaced slightly toward more radiogenic Sr. Pb isotope covariations show that all the Eocene-Oligocene samples plot along the Northern Hemisphere Reference Line, indicating little or no Pb derived from subducted pelagic sediment in their source. Two young basaltic andesite clasts within sediment do have a pelagic sediment signature but this may have been gained by alteration rather than subduction. In all isotopic projections, the samples form consistent groupings: the tholeiites from Site 782 and Hole 786A plot closest to PMM, the boninites and related rocks from Sites 786B plot closest to PVS, and the boninite lavas from Hole 786A and late boninitic dikes from Hole 786B occupy an intermediate position. Isotope-trace element covariations indicate that these isotopic variations can be explained by a three-component mixing model. One component (A) has the isotopic signature of PMM but is depleted in the more incompatible elements. It is interpreted as representing suboceanic mantle lithosphere. A second component (B) is relatively radiogenic (eNd = ca 4-6; 206Pb/204Pb = ca 19.0-19.3; eSr = ca -10 to -6)). Its trace element pattern has, among other characteristics, a high Zr/Sm ratio, which distinguishes it from the "normal" fluid components associated with subduction and hotspot activity. There are insufficient data at present to tie down its origin: probably it was either derived from subducted lithosphere or volcanogenic sediment fused in amphibolite facies; or it represents an asthenospheric melt component that has been fractionated by interaction with amphibole-bearing mantle. The third component (C) is characterized by high contents of Sr and high eSr values and is interpreted as a subducted fluid component. The mixing line on a diagram of Zr/Sr against e Sr suggests that component C may have enriched the lithosphere (component A) before component B. These components may also be present on a regional basis but, if so, may not have had uniform compositions. Only the boninitic series from nearby Chichijima would require an additional, pelagic sediment component. In general, these results are consistent with models of subduction of ridges and young lithosphere during the change from a ridge-transform to subduction geometry at the initiation of subduction in the Western Pacific.

The formation of continental crust during the Archean and early Proterozoic occurred through a different mechanisms than the currently active processes of calc-alkaline volcanism in orogenic regions. In view that most crustal growth models imply that by the end of the Archean a continental mass equivalent to 75% or more of the current crust had evolved, it seems highly relevant to study early crustal genesis.

Experiments have been conducted to study contamination of magmas in four environments : (1) above subducted slabs, (2) below and (3) above the mantle-continental crust boundary, and (4) within shallow crust. Reaction couples of peridotite or amphibolite with a sharp boundary against hydrous silicic melts define (1) diffusion profiles within contaminated melts and (2) crystalline reaction zones between the two materials. Mixtures of rocks peridotite-tonalite-granodiorite-granite with water define phase boundaries delineating the extent of contamination of slab-derived melts rising through mantle and of crustal melts in contact with peridotites {e.g., cumulates). Chemical diffusion in granite melts at 1.5 kbar, 810 °C is slow ; diffusion between hot, hydrous basalt-rhyolite at 10 kbar is faster. Convection occurs in H20-undersaturated granite melt at 10-15 kbar, 920-1050 °C, during passage of a melting front through crystalline granite adjacent serpentinized peridotite, the source of H_2O; the convective motions transport contaminated melt away from the diffusion zone, which therefore remains narrow. Rates of contamination and mixing of magmas near the mantle-crust boundary are likely to be much faster than in shallow crustal plutons. Slab-derived melts are richer in Ca/Mg than calc-alkaline rocks, and contamination with overlying mantle at depth makes them richer in Mg/Ca than calc-alkaline rocks. Near the mantle crust boundary, Ca/Mg in contamined melts is appropriate for calc-alkaline rocks.

The Surface Ocean CO₂ Atlas (SOCAT), an activity of the international marine carbon research community, provides access to synthesis and gridded fCO₂ (fugacity of carbon dioxide) products for the surface oceans. Version 2 of SOCAT is an update of the previous release (version 1) with more data (increased from 6.3 million to 10.1 million surface water fCO₂ values) and extended data coverage (from 1968–2007 to 1968–2011). The quality control criteria, while identical in both versions, have been applied more strictly in version 2 than in version 1. The SOCAT website (http://www.socat.info/) has links to quality control comments, metadata, individual data set files, and synthesis and gridded data products. Interactive online tools allow visitors to explore the richness of the data. Applications of SOCAT include process studies, quantification of the ocean carbon sink and its spatial, seasonal, year-to-year and longerterm variation, as well as initialisation or validation of ocean carbon models and coupled climate-carbon models.

Knowledge of the depth of solidification of talc-alkalic plutons is critical to understanding and unraveling the complex spatial, temporal, and chemical evolution of orogenic belts. An empirical geobarometer has recently been proposed based on the total Al content (AlT) of near-solidus calcic hornblendes in tonalite and granodiorite intrusive rocks in the pressure range < 1 to 8 kbar. Pressures were estimated from mineral assemblages in associated metamorphic country rocks. We report experimental data on newly crystallized near-solidus amphiboles in partly melted, vapor-absent garnet tonalite at 10 kbar that provide some experimental support for the proposed geobarometer consistent with the extrapolated empirical result, and confirm its limited applicability to specific, multimineral assemblages.