Anomalous phosphorus episodes during Callovian-Oxfordian times in the Kachchh Basin,western India: Implications for palaeoclimate,productivity, and weathering     

Muthuvairavasamy Ramkumar  Matthias Alberti  Franz T. Fürsich  Dhirendra Kumar Pandey 《Chemie der Erde / Geochemistry》2012,72(2):141-148

The Upper Callovian-Oxfordian strata of the Kachchh Basin, western India, record three positive excursions of phosphorus. They have been documented in three sections of the Chari Formation from different parts of the basin. Corroboration of field and petrographic data with trends of major and trace elemental data and elemental ratios of the strata revealed that these excursions were coeval with reduced chemical weathering in the source area and significant reduction of siliciclastic influx to the depositional sites. The study also revealed the intrabasinal source of P, and minor sea-level fluctuations and resultant episodic sediment recycling as the causative factors. Considering the geographic locations of the three sections, the phosphorus anomalies seem to be controlled by a regional and/or basin-scale process, if not linked with global signals. Temporal resolution of these anomalies suggests that the processes were episodic and related to short term climate/relative sea-level cycles, the durations of which could be unraveled with high-resolution biostratigraphic data.  相似文献   

U-Pb zircon geochronology, geochemistry and kinetics of the Huaniushan A-type granite in Northwest China   总被引：1，自引：0，他引：1  

Jiang Zhu  Xinbiao Lü  Xiaofeng Cao  Yalong Mo  Chao Chen 《中国地球化学学报》2012,31(1):85-94

The Huaniushan granite is located at the Beishan orogenic belt, northwestern China. At the contact zone between the granite and marble, a hydrothermal Pb-Zn and skarn Au deposit is formed. LA-ICP-MS zircon U-Pb dating yielded a weighted mean 206Pb/238U age of 229.5±2.6 Ma (MSDW=0.93) for the Huaniushan granite, imply-ing its Late Triassic intrusion. Geochemistry analyses show that the Huaniushan granite is enriched in Si, K, Na, and REE, and depleted in Mg and Ca, with contents of SiO2 (70.8% to 74.4%), Na2O+K2O (8.8% to 10.2%), CaO (0.93% to 1.44%), and MgO (0.14% to 0.48%). REE is characterized by obvious negative Eu anomaly. Rb, Th, U, K, Pb, Nb, Zr and Hf elements are rich in the granite while Ba, Sr, P, Ti and Eu are deplete. The granite has a high (Zr+Nb+Ce+Y) abundance and 104 Ga/Al ratios. Petrology, major and trace elements data all indicate that the Hua-niushan granite is A-type granite which intruded in a post-collisional extensional tectonic setting. The magma was dominantly sourced from partial melting of crustal intermediate-felsic igneous rocks. Intensive magmatic activities and Au-Cu-Mo mineralization occurred throughout the Beishan orogenic belt during the period from ca. 240 to 220 Ma.  相似文献   

Pharmaceuticals as indictors of sewage-influenced groundwater   总被引：1，自引：0，他引：1  

Beate Müller  Traugott Scheytt  Martin Asbrand  Andrea Mross de Casas 《Hydrogeology Journal》2012,20(6):1117-1129

A set of human pharmaceuticals enables identification of groundwater that is influenced by sewage and provides information on the time of recharge. As the consumption rates of the investigated pharmaceuticals have changed over time, so too has the composition of the sewage. At the study area, south of Berlin (Germany), irrigation was performed as a method of wastewater clean-up at sewage irrigation farms until the early 1990s. Today, treated wastewater is discharged into the surface-water-stream Nuthegraben. Groundwater and surface-water samples were analyzed for the pharmaceutical substances clofibric acid, bezafibrate, diclofenac, carbamazepine and primidone, the main ions and organic carbon. The pharmaceutical substances were detected at concentrations up to microgram-per-liter level in groundwater and surface-water samples from the Nuthegraben Lowland area and from the former irrigation farms. Concentrations detected in groundwater are generally much lower than in surface water and there is significant variation in the distribution of pharmaceutical concentrations in groundwater. Groundwater influenced by the irrigation of sewage water shows higher primidone and clofibric-acid concentrations. Groundwater influenced by recent discharge of treated sewage water into the surface water shows high carbamazepine concentrations while concentrations of primidone and clofibric acid are low.  相似文献   

Zircon response to high-grade metamorphism as revealed by U–Pb and cathodoluminescence studies     

W. Siebel  C. K. Shang  E. Thern  M. Dani?ík  J. Rohrmüller 《International Journal of Earth Sciences》2012,101(8):2105-2123

Correct interpretation of zircon ages from high-grade metamorphic terrains poses a major challenge because of the differential response of the U–Pb system to metamorphism, and many aspects like pressure–temperature conditions, metamorphic mineral transformations and textural properties of the zircon crystals have to be explored. A large (c. 450?km²) coherent migmatite complex was recently discovered in the Bohemian Massif, Central European Variscides. Rocks from this complex are characterized by granulite- and amphibolite-facies mineral assemblages and, based on compositional and isotopic trends, are identified as the remnants of a magma body derived from mixing between tonalite and supracrustal rocks. Zircon crystals from the migmatites are exclusively large (200–400?μm) and yield ²⁰⁷Pb/²⁰⁶Pb evaporation ages between 342–328?Ma and single-grain zircon fractions analysed by U–Pb ID-TIMS method plot along the concordia curve between 342 and 325?Ma. High-resolution U–Pb SHRIMP analyses substantiate the existence of a resolvable age variability and yield older ²⁰⁶Pb/²³⁸U ages (342–330?Ma, weighted mean age?=?333.6?±?3.1?Ma) for inner zone domains without relict cores and younger ²⁰⁶Pb/²³⁸U ages (333–320?Ma, weighted mean age?=?326.0?±?2.8?Ma) for rim domains. Pre-metamorphic cores were identified only in one sample (²⁰⁶Pb/²³⁸U ages at 375.0?±?3.9, 420.3?±?4.4 and 426.2?±?4.4?Ma). Most zircon ages bracket the time span between granulite-facies metamorphism in the Bohemian Massif (~345?Ma) and the late-Variscan anatectic overprint (Bavarian phase, ~325?Ma). It is argued that pre-existing zircon was variously affected by these metamorphic events and that primary magmatic growth zones were replaced by secondary textures as a result of diffusion reaction processes and replacement of zircon by dissolution and recrystallization followed by new zircon rim growth. Collectively, the results show that the zircons equilibrated during high-grade metamorphism and record partial loss of radiogenic Pb during post-peak granulite events and new growth under subsequent anatectic conditions.  相似文献   

Early Triassic potassic volcanism in the Afyon Zone of the Anatolides/Turkey: implications for the rifting of the Neo-Tethys     

Cüneyt Akal  Osman Candan  O. Ersin Koralay  Roland Oberhänsli  Fukun Chen  Dejan Prelević 《International Journal of Earth Sciences》2012,101(1):177-194

Afyon Zone, which was derived from the Anatolide–Tauride platform during closure of the Neo-Tethys, is made up of pre-Mesozoic basement and unconformably overlying Triassic–Early Tertiary cover series. The Afyon Zone contains widespread metavolcanic rocks, which are dominated by rhyolite, dacite, and trachyandesite. They form a distinct volcanic succession, which is separated from the underlying Silurian–Lower Carboniferous metacarbonates and meta-siliciclastics by a regional unconformity. Trachyandesitic metavolcanics are made up of massive lava flows, pyroclastics and epiclastics, less frequently, domes and dikes, which were developed on a deeply eroded subaerial landmass. U/Pb and Pb/Pb zircon geochronology yielded Lower Triassic (~250 Ma) ages, which are interpreted as extrusion age of trachyandesitic volcanics. Based on the stratigraphic, geochronological, and geochemical data, we suggest that these Lower Triassic magmatic rocks represent an extensional tectonic setting on the northern active margin of the Gondwana, which led to the development of the northern branch of the Neo-Tethys.  相似文献   

Preface: clay mineral diagenesis and very low-grade metamorphic processes. Proceedings of the 2011 Frey–Kübler symposium     

Rafael Ferreiro M?hlmann  Fernando Nieto  ?mer Bozkaya  Sébastien Potel  Asuman Günal Türkmeno?lu 《Swiss Journal of Geoscience》2012,105(2):117-120

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Integrated Water Resources Management under different hydrological,climatic and socio-economic conditions   总被引：2，自引：2，他引：0  

Edda Kalbus  Thomas Kalbacher  Olaf Kolditz  Elisabeth Krüger  Jörg Seegert  Gunda Röstel  Georg Teutsch  Dietrich Borchardt  Peter Krebs 《Environmental Earth Sciences》2012,65(5):1363-1366

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GIS-based landslide susceptibility mapping using bivariate statistical analysis in Devrek (Zonguldak-Turkey)   总被引：15，自引：10，他引：5  

Cagatay Yilmaz  Tamer Topal  Mehmet Lütfi Süzen 《Environmental Earth Sciences》2012,65(7):2161-2178

Devrek town with increasing population is located in a hillslope area where some landslides exist. Therefore, landslide susceptibility map of the area is required. The purpose of this study was to generate a landslide susceptibility map using a bivariate statistical index and evaluate and compare the results of the statistical analysis conducted with three different approaches in seed cell concept resulting in different data sets in Geographical Information Systems (GIS) based landslide susceptibility mapping applied to the Devrek region. The data sets are created from the seed cells of (a) crowns and flanks, (b) only crowns, and (c) only flanks of the landslides by using ten different causative parameters of the study area. To increase the data dependency of the analysis, all parameter maps are classified into equal frequency classes based directly on the percentile divisions of each corresponding seed cell data set. The resultant maps of the landslide susceptibility analysis indicate that all data sets produce fairly acceptable results. In each data set analysis, elevation, lithology, slope, aspect, and drainage density parameters are found to be the most contributing factors in landslide occurrences. The results of the three data sets are compared using Seed Cell Area Indexes (SCAI). This comparison shows that the crown data set produces the most accurate and successful landslide susceptibility map of the study area.  相似文献   

Heavy metal pollution in the surrounding ore deposits and mining activity: a case study from Koyulhisar (Sivas-Turkey)   总被引：1，自引：1，他引：0  

Tülay Ekemen Keskin  Sonay Topta? 《Environmental Earth Sciences》2012,67(3):859-866

The oxidation of sulfide minerals generates acidic waters containing high levels of SO₄ and Fe. The study area has active Pb?CZn?CCu mining. It is thought that the surface/subsurface/underground sulfide minerals in the region generally contribute to the acidification of groundwater. Low pH values are also responsible for dissolved metals (Al, Fe, Mn, SO₄, Pb, Zn) in the groundwater and river. Furthermore, current mining wastes have affected concentrations of trace elements in the water. High Fe and Mn concentrations are generally found in the spring which has acidic and low Eh values, while Al, Fe and Mn concentrations in the acidic waters show notable increases with the maximum values reaching 8,829, 19,084 and 1,708?ppb, respectively. These values exceed the Turkish drinking water standard of 200, 200 and 50?ppb, respectively.  相似文献   

Europe’s longest-operating on-shore CO2 storage site at Ketzin, Germany: a progress report after three years of injection   总被引：3，自引：3，他引：0  

S. Martens  T. Kempka  A. Liebscher  S. Lüth  F. M?ller  A. Myrttinen  B. Norden  C. Schmidt-Hattenberger  M. Zimmer  M. Kühn 《Environmental Earth Sciences》2012,67(2):323-334

The Ketzin pilot site, led by the GFZ German Research Centre for Geosciences, is Europe??s longest-operating on-shore CO₂ storage site with the aim of increasing the understanding of geological storage of CO₂ in saline aquifers. Located near Berlin, the Ketzin pilot site is an in situ laboratory for CO₂ storage in an anticlinal structure in the Northeast German Basin. Starting research within the framework of the EU project CO₂SINK in 2004, Ketzin is Germany??s first CO₂ storage site and fully in use since the injection began in June 2008. After 39?months of operation, about 53,000 tonnes of CO₂ have been stored in 630?C650?m deep sandstone units of the Upper Triassic Stuttgart Formation. An extensive monitoring program integrates geological, geophysical and geochemical investigations at Ketzin for a comprehensive characterization of the reservoir and the CO₂ migration at various scales. Integrating a unique field and laboratory data set, both static geological modeling and dynamic simulations are regularly updated. The Ketzin project successfully demonstrates CO₂ storage in a saline aquifer on a research scale. The results of monitoring and modeling can be summarized as follows: (1) Since the start of the CO₂ injection in June 2008, the operation has been running reliably and safely. (2) Downhole pressure data prove correlation between the injection rate and the reservoir pressure and indicates the presence of an overall dynamic equilibrium within the reservoir. (3) The extensive geochemical and geophysical monitoring program is capable of detecting CO₂ on different scales and gives no indication for any leakage. (4) Numerical simulations (history matching) are in good agreement with the monitoring results.  相似文献