Characterization and migration of atmospheric REE in soils and surface waters

Rainwater and snow collected from three different sites in France (Vosges Mountains, French Alps and Strasbourg) show more or less similar shapes of their REE distribution patterns. Rainwater from Strasbourg is the most REE enriched sample, whereas precipitations from the two mountainous, less polluted catchments are less REE enriched and have concentrations close to seawater. They are all strongly LREE depleted.Different water samples from an Alpine watershed comprising snow, interstitial, puddle and streamwater show similar REE distributions with LREE enrichment (rainwater normalized) but MREE and HREE depletion. In this environment, where water transfer from the soil to the river is very quick due to the low thickness of the soils, it appears that REE in streamwater mainly originate from atmospheric inputs. Different is the behaviour of the REE in the spring- and streamwaters from the Vosges Mountains. These waters of long residence time in the deep soil horizons react with soil and bedrock REE carrying minerals and show especially significant negative Eu anomalies compared to atmospheric inputs. Their Sr and Nd isotopic data suggest that most of the Sr and Nd originate from apatite leaching or dissolution. Soil solutions and soil leachates from the upper soil horizons due to alteration processes strongly depleted in REE carrying minerals, have REE distribution patterns close to those of lichens and throughfall. Throughfall is slightly more enriched especially in light REE than filtered rainwater probably due to leaching of atmospheric particles deposited on the foliage and also to leaf excretion.Data suggest that Sr and Nd isotopes of the soil solutions in the upper soil horizons originate from two different sources: 1) An atmospheric source with fertilizer, dust and seawater components and 2) A source mainly determined by mineral dissolution in the soil. These two different sources are also recognizable in the Sr and Nd isotopic composition of the tree’s throughfall solution. The atmospheric contributions of Sr and Nd to throughfall and soil solution are of 20 to 70 and 20%, respectively. In springwater, however, the atmospheric Sr and REE contribution is not detectable.     

How Well Does Chlorophyll Explain the Seasonal Variation in Phytoplankton Activity?

The seasonal variation in phytoplankton activity is determined by analysing 1385 primary production (PP) profiles, chlorophyll a (Chl) concentration profiles and phytoplankton carbon biomass concentrations (C) from the period 1998–2012. The data was collected at six different stations in the Baltic Sea transition zone (BSTZ) which is a location with strong seasonal production patterns with light as the key parameter controlling this productivity. We show that the use of Chl as a proxy for phytoplankton activity strongly overestimates the contribution from the spring production to annual pelagic carbon flow. Spring (February and March) Chl comprised 16–30% of the total annual Chl produced, whereas spring C was much lower (8–23%) compared to the annual C. Spring PP accounted for 10–18% of the total annual PP, while the July–August production contributed 26–33%, i.e. within the time frame when zooplankton biomass and grazing pressure are highest. That is, Chl failed in this study to reflect the importance of the high summer PP. A better proxy for biomass may be C, which correlated well with the seasonal pattern of PP (Pearson correlation, p < 0.05). Thus, this study suggests to account for the strong seasonal pattern in C/Chl ratios when considering carbon flow in coastal systems. Seasonal data for PP were fitted to a simple sinusoidal wave model describing the seasonal distribution of PP in the BSTZ and were proposed to present a better parameterizaton of PP in shallow stratified temperate regions than more commonly applied proxies.     

Fingerprinting the 8.2 ka event climate response in a coupled climate model

Using results from coupled climate model simulations of the 8.2 ka climate event that produced a cold period over Greenland in agreement with the reconstructed cooling from ice cores, we investigate the typical pattern of climate anomalies (fingerprint) to provide a framework for the interpretation of global proxy data for the 8.2 ka climate event. For this purpose we developed an analysis method that isolates the forced temperature response and provides information on spatial variations in magnitude, timing and duration that characterise the detectable climate event in proxy archives. Our analysis shows that delays in the temperature response to the freshwater forcing are present, mostly in the order of decades (30 a over central Greenland). The North Atlantic Ocean initially cools in response to the freshwater perturbation, followed in certain parts by a warm response. This delay, occurring more than 200 a after the freshwater pulse, hints at an overshoot in the recovery from the freshwater perturbation. The South Atlantic and the Southern Ocean show a warm response reflecting the bipolar seesaw effect. The duration of the simulated event varies for different areas, and the highest probability of recording the event in proxy archives is in the North Atlantic Ocean area north of 40° N. Our results may facilitate the interpretation of proxy archives recording the 8.2 ka event, as they show that timing and duration cannot be assumed to correspond with the timing and duration of the event as recorded in Greenland ice cores. Copyright © 2011 John Wiley & Sons, Ltd.     

Subglacial emplacement of tills and meltwater deposits at the base of overdeepened bedrock troughs

The sedimentary infills of subglacially eroded bedrock troughs in the Alps are underexplored archives for the timing, extent and character of Pleistocene glaciations but may contain excellent records of the Quaternary landscape evolution over several glacial–interglacial cycles. The onset of sedimentation in these bedrock troughs is often reflected by diamicts and gravels directly overlying bedrock in the deepest basin segments. Subglacial or proglacial depositional environments have been proposed for these coarse‐grained basal units but their characteristics and origin remain controversial. This article presents results from drill cores that recovered a coarse‐grained basal unit in a major buried bedrock‐trough system in the Lower Glatt Valley, northern Switzerland. The excellent core recovery allowed a detailed study combining macroscopic, microscopic and geochemical methods and gives unprecedented insights into the transition from erosion to deposition in overdeepened bedrock troughs. These results show that the basal infill comprises diamicts, interpreted as subglacial tills, separated by thin sorted interbeds, originating from subglacial cavity deposition. The stacking of these units is interpreted to represent repeated switching between a coupled and decoupled ice–bed‐interface indicating an ever‐transforming mosaic of subglacial bed conditions. Decoupling in response to high basal water pressures is probably promoted by the confined subglacial hydraulic conditions resulting from the bedrock acting as aquitards, the narrow reverse sloping outlet and a large catchment area. While stratigraphic and lithological evidence suggests that erosion and the onset of basal sedimentation occurred during the same glaciation, different scenarios for the relative timing of infilling in relation to formation and glaciation of the bedrock trough are discussed. Overlying deltaic and glaciolacustrine sediments suggest deposition during subsequent deglaciation of the bedrock trough. The basal sediment characteristics are in agreement with previous reports in hydrogeological and seismic exploration and suggest the occurrence of similar basal successions in other subglacially overdeepened basins in the Alps and elsewhere.     

Non-monotonic Responses of Phytoplankton Biomass Accumulation to Hydrologic Variability: A Comparison of Two Coastal Plain North Carolina Estuaries

Freshwater inputs often play a more direct role in estuarine phytoplankton biomass (chlorophyll a) accumulation than nitrogen (N) inputs, since discharge simultaneously controls both phytoplankton residence time and N loading. Understanding this link is critical, given potential changes in climate and human activities that may affect discharge and watershed N supply. Chlorophyll a (chla) relationships with hydrologic variability were examined in 3-year time series from two neighboring, shallow (<5?m), microtidal estuaries (New and Neuse River estuaries, NC, USA) influenced by the same climatic conditions and events. Under conditions ranging from drought to floods, N concentration and salinity showed direct positive and negative responses, respectively, to discharge for both estuaries. The response of chla to discharge was more complex, but was elucidated through conversion of discharge to freshwater flushing time, an estimate of transport time scale. Non-linear fits of chla to flushing time revealed non-monotonic, unimodal relationships that reflected the changing balance between intrinsic growth and losses through time and along the axis of each estuary. Maximum biomass occurred at approximately 10-day flushing times for both systems. Residual analysis of the fitted data revealed positive relationships between chla and temperature, suggesting enhanced growth rates at higher temperatures. N loading and system-wide, volume-weighted chla were positively correlated, and biomass yields per N load were greater than other marine systems. When combined with information on loss processes, these results on the hydrologic control of phytoplankton biomass will help formulate mechanistic models necessary to predict ecosystem responses to future climate and anthropogenic changes.     

Development and changes in the Eastern Province of Saudi Arabia

Due to a particularly favourable geologic and tectonic setting in the Eastern Province, Saudi Arabia has the world largest oil reserves and is the third largest oil-producing nation in the world. Based on oil and gas revenues, the Kingdom experienced an overwhelming development during the last few decades, changing a desert country into a modern industrialized nation. Main characteristics of spatial changes are based on processes of urbanization and industrialization, on agricultural reclamations and infra-structural developments. Since the natural environment of deserts and semi-deserts in the Eastern Province is determined by an extremely sensitive equilibrium, environmental impacts, shortages in water resources, as well as limited human resources are causing basic problems, which will influence future developments.     

The stream function and Gauss' principle of least constraint: Two useful concepts for structural geology

To the extent that rock deformation can be approximated by a two-dimensional Newtonian model, a powerful stream-function simulation method is applicable. The significance of stream functions is that velocity, strain, stress and energy derived from the same stream function satisfy automatically three basic conditions of dynamics:

1. (1) the condition of continuity.

2. (2) the Navier-Stokes equations.

3. (3) conservation of energy.

Hence we state with Jaeger: “If a stream function can be found which satisfies the boundary conditions of a dynamic model the complete solution follows.” All pertinent bits of dynamic information are implied in the stream function from which they can be directly derived, guaranteed—so to speak—not to violate the basic conditions of dynamics. Stream functions useful in structural geology are solutions of: A double-polynomial solution of max. degree 14 is developed, in which the coefficients are related controlled by the ⁴ψ = 0 constraint, and their absolute values are determined by the boundary conditions of specific models and by the condition of maximum rate of energy dissipation or maximum rate of decline of potential energy. The polynomial stream function is applied to a collapsing viscous “nappe” consisting of a thin basal layer with low viscosity on which a thicker layer with high viscosity slides due to gravitational spreading. The velocity of forward movement depends upon absolute and relative values of the following parameters: viscosity, thickness, the aspect ratio and density. The velocity of a variety of nappes with different thicknesses, aspect ratios, viscosities and densities is determined.     

Beiträge zur Geologie der Insel Salina (Äolischer Archipel,Sizilien)

Zusammenfassung Auf Salina beginnt die vulkanische Tätigkeit mit der Förderung von Labradorit-Andesiten und -Trachyandesiten, die den alten Pollara-Vulkan und den Vulkanstock des Mte. Rivi aufbauen. Der letzte wird von mindestens zwei größeren Vulkanen — dem südwestlichen und dem nordöstlichen Mte. Rivi-Vulkan — zusammengesetzt. Anschließend kam es im Südosten der Insel zu der Extrusion sauerer Laven in Form von Staukuppen und Staurücken (mit rhyodazitischem Chemismus).Im Bereich der alten Rivi-Vulkane und jenem der saueren Laven im SE-Teil von Salina sind marine Brandungsterrassen mit 2- bis 4 m mächtigen, groben Küstenkonglomeraten nachweisbar: sie haben Höhen von maximal + 30 m (NE-Teil von Salina) und + 10 bis + 15 m (SE-Teil der Insel). Da diese beiden Terrassensysteme auch auf anderen Inseln des Archipels ausgebildet sind, wird ihre Entstehung durch eustatische Spiegelschwankungen des Mittelmeeres während des Pleistozäns erklärt: die höheren Terrassen entsprechen dem Tyrrhenien I (Mindel/Riß-Interglazial — oberes Mittelpleistozän), die tieferen dürften dem Monastirien I/II (= Tyrrhenien II — Riß/Würm-Interglazial — mittleres Jungpleistozän) zuzuordnen sein. Der Beginn der vulkanischen Tätigkeit im Bereich des Äolischen Archipels muß damit wesentlich jünger als bisher angenommen angesetzt werden: nämlich nicht im Miozän und Frühpliozän, sondern erst im Quartär beginnend.Im jüngeren Quartär bildeten sich auf Salina etwa gleichzeitig die beiden großen Stratovulkankegel des Mte. dei Porri und der Fossa delle Felci, die nicht basischen Chemismus aufweisen, wie bisher angenommen wurde, sondern von rhyodazitischen Laven und Tuffen zusammengesetzt werden. Sie sind altersmäßig mit dem großen Stratovulkan auf Lipari — dem Mte. S. Angelo — zu parallelisieren.Als jüngstes vulkanisches Ereignis auf Salina fand die Aussprengung des großen Kraters von Pollara und die Förderung quarzlatitischer Bimssteine statt. Diese Bimsstein-Tuffe führen reichlich xenolithische Auswürflinge, unter denen granitische bis dioritische Tiefengesteine, kristalline Schiefer, Marmore, Kalksilikatfelse und thermometamorph sehr wenig veränderte, reichlichglobigerinen-führende mergelige Kalke des Tertiärs besonders auffallen. Als untermeerischer Sockel der Äolischen Inseln ist damit die NW-Fortsetzung der Kalabrisch-Peloritanischen Masse belegt.Der Vulkanismus der Äolischen Provinz ist durch die posthume quartäre Bruchtektonik im Raum der heutigen Tyrrhenis bedingt. Durch diese Schollenbewegungen entstanden Brüche, längs denen sialisch-anatektische Restmagmen pazifischer Sippe empordringen konnten.

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The volcanic activity on the island of Salina (Eolian archipelago) began with the eruption of labradorite-andesites and trachyandesites, which compose the old volcano of Pollara and that of Mte. Rivi. Thereupon endogenous domes with rhyodacitic chemism had been formed in the southeastern part of the island.In the region of the above mentioned old volcanoes and domes two old coastlines are developed: the higher is recognizable in the northeastern part of Salina and lies + 30 m above sea-level, the lower one is exposed in the southeastern part of the island and differs between + 10 and + 15 m above sea-level. These old coast-lines are likewise developed on other islands of the Eolian archipelago. By this fact their origin is interpreted by eustatic variations of the sea-level in the Mediterranian during the Pleistocene. The higher coast-lines are corresponding to the Tyrrhenian I (= upper part of the middle-Pleistocene), the lower ones are paralleled with the Monastirian I/II (= Tyrrhenian II = middle part of the upper-Pleistocene). By these facts it becomes apparently, that the volcanic activity in the Eolian archipelago began not in Miocene and lower Pliocene, but only in Quaternary times.The volcanism on Salina continued in the younger Quaternary with the approximately contemporaneous formation of two great strato-volcanoes (Mte. dei Porri and Fossa delle Felci), which are of rhyodacitic, but not of basaltic chemism as hitherto assumed. The youngest volcanic event was the ejection of quartz-latitic pumices and the formation of the great crater of Pollara. These pumice-tuffs are rich in xenolithic ejecta (as for instance granitic and dioritic rocks, gneisses, marbles, calc-silicate rocks formed by contact metamorphism, and slightly altered marly limestones of Tertiary age, rich in globigerines). These xenolithes are the proof, that the base of the Eolian Islands is represented by the continuation of the Calabrian-Peloritanian Massive.The volcanism of the Eolian volcanic province was caused by Quaternary tectonics, which were the result of subsidence of the Tyrrhenian Block. Along the fault fissures sialic-anatectic residual-magmas of Pacific rock suite were erupted.

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Résumé L'activité volcanique débute à Salina avec l'éruption d'andésites e trachyandésites à labradorite qui ont formé l'ancien volcan Pollara et le piton volcanique du Mte. Rivi. Ce dernier est composé d'au moins 2 grands volcans, le Mte. Rivi sudoccidental et nord-oriental. Vint en plus dans le sud-est de l'île une extrusion de laves acides en forme de coupoles et de crêtons (à chimisme rhyodacite).Dans la région de l'ancien volcan Rivi et de ces laves acides de la partie SE de Salina, on trouve des terrasses marines formées de conglomérats côtiers grossiers de 2 à 4 m d'épaisseur: leur altitude maximum est de + 30m (NE de Salina) et + 10 m à +15 (SE de l'île). Comme ces 2 systèmes de terrasses se rencontrent également sur d'autres îles de l'archipel, on explique leur origine par des variations eustatiques du niveau de la mer durant le Pléistocène: les terrasses supérieures appartiennent au Tyrrhénien I (Interglaciaire Mindel/Risspartie supérieure du Pléistocène moyen); les terrasses inférieures devraient appartenir au Monastirien I/II (=Tyrrhénien II ⦌- Interglaciaire Riss/Würm — partie moyenne du Pléistocène supérieur). L'activité volcanique dans l'archipel éolien aurait ainsi débuté nettement plus tard qu'on ne l'a considéré jusqu'ici: non pas au Miocène ou au début du Pliocène, mais seulement au Quaternaire.Au Quaternaire récent il s'est formé à Salina presque en même temps les 2 grands stratovolcans du Monte dei Porri et de la Fossa delle Felci, qui n'ont pas un chimisme basique comme on l'admettait jusqu'ici, mais qui sont composés de laves et tuffs rhyodacitiques. Du point de vue de l'âge ils sont à paralléliser avec le grand stratovolcan de Lipari, le Mte. S. Angelo.La manifestation volcanique la plus récente à Salina fut l'explosion du grand cratère de Pollara et l'émission de ponces de composition latitique acide. Ces tuffs contiennent de nombreux xénolithes parmi lesquels on remarque surtout des roches profondes granitiques à dioritiques, des schistes cristallins, des marbres, des roches à silicates calcaires, et des calcaires marneux du Tertiaire, riches en globigérines et très peu thermométamorphisés.Le socle sous-marin des îles éoliennes serait donc le prolongement NW de la masse calabro-péloritaine.Le volcanisme de la province éolienne est causé par la tectonique cassante quaternaire dans le cadre de la Tyrrhénide actuelle. Grâce aux mouvements de ces blocs, des cassures ont pris naissance par lesquelles ont pu monter les magmas résiduels sialiques-anatectiques appartenant à la série pacifique.

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Riassunto Sull'isola di Salina (archipelago Eoliano) l'attività vulcanica inizia con l'emissione di lave trachiandesiti- e andesiti-labradoritiche, che formano il vecchio vulcano di Pollara ed il massivo vulcanico del Mte. Rivi. L'ultimo è formato da almeno due grandi vulcani — il vulcano sudovest ed il vulcano nordest di Mte. Rivi — die adesso in maggior parte sono degradati e distrutti. Dopo c'è stata nella parte sudest dell'isola l'estrusione di lave acide, che formano le cupole all'occidente di Lingua (con chimismo riodazitico).Nella zona dei vecchi vulcani di Mte. Rivi e quella delle rocce acide nella parte sudest di Salina sono da constatare terrazze marine con grossi conglomerati litorale della potenza di 2–4 m. L'altitudine di queste terrazze marine è al massimo di + 30 m (parte NE di Salina) e tra + 10 e + 15 m (parte SE dell'isola). Poichè questi due sistemi di terrazze marine si trovano anche sull'altre isole dell'archipelago (Lipari, Panarea, Filicudi) si spiega la loro origine da oscillazioni eustatiche del Mediterraneo durante il Pleistocene: le terrazze superiori corrispondono al Tirreniano I (medio-Pleistocene superiore), le terrazze inferiori forse sono appartenenti al Monastiriano I/II (= Tirreniano II, medio tardo-Pleistocene). L'inizio dell'attività vulcanica nella provincia Eolia perció è più giovane come si pensava finora: cioè non è stato durante il Miocene e Pliocene inferiore, ma soltanto nel Quaternario.Nel Quaternario giovane si formarono a Salina quasi contemporaneamente i due grandi strato-vulcani del Mte. dei Porri e della Fossa delle Felci, che non dimostrano un chimismo basico come è stato scritto finora ma sono composti di lave e tufi riodazitiche. Nell'età essi corrispondono al grande strato-vulcano su Lipari — il Mte. S. Angelo.Il più giovane awenimento vulcanico a Salina è stato la formazione del grande cratere di Pollara con espulsione di pomice quarzlatitica. In questa pomice componenti xenolitici sono abbondanti per esempio tali di graniti, granodioriti, dioriti, scisti cristallini, marmi, rocce a calcare-silicatiche e calcari marnosi tertiari poco alterati termometamorfici con abbondante globigerine. Lo zoccolo sottomarino dell'archipelago Eoliano è così la continuazione ipotetica della massa calabro-peloritanica. Il vulcanismo della provincia Eolia è causato dalla tettonica germanotipica quaternaria nella zona del Tirreno. Per l'effetto dello sprofondamento della massa del Tirreno si formarono grandi faglie, lungo a queste salivano magmi sialici-anatectici pacifici.

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Der geologische Bau Nowaja Semljas und seine Beziehungen zu anderen Gebieten im Lichte neuerer Forschungen

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