The petrogenesis of granitoid rocks unusually rich in apatite in the Western Tatra Mts. (S-Poland, Western Carpathians)     

Krzysztof Szopa  Aleksandra Gawęda  Axel Müller  Magdalena Sikorska 《Mineralogy and Petrology》2013,107(4):609-627

In the bottom part of the tongue-shaped, layered granitoid intrusion, exposed in the Western Tatra Mts., apatite-rich granitic rocks occur as pseudo-layers and pockets between I-type hybrid mafic precursors and homogeneous S-type felsic granitoids. The apatite-rich rocks are peraluminous (ASI?=?1.12–1.61), with P₂O₅ contents ranging from 0.05 to 3.41 wt.% (<7.5 vol.% apatite), shoshonitic to high-K calc-alkaline. Apatite is present as long-prismatic zoned crystals (Ap₁) and as large xenomorphic unzoned crystals (Ap₂). Ap₁ apatite and biotite represent an early cumulate. Feldspar and Ap₂ textural relations may reflect the interaction of the crystal faces of both minerals and support a model based on local saturation of (P, Ca, F) versus (K, Na, Al, Si, Ba) in the border zones. Chondrite-normalized REE patterns for the apatite rocks and for pure apatite suggest apatite was a main REE carrier in these rocks. Minerals characteristics and the whole rock chemistry suggest both reduced S-type and I-type magma influenced the apatite-rich rocks. The field observations, mineral and rock chemistry as well as mass-balance calculations point out that the presence of apatite-rich rocks may be linked to the continuous mixing of felsic and mafic magmas, creating unique phosphorus- and aluminium-rich magma portions. Formation of these rocks was initially dominated by the complex flowage-controlled and to some extent also gravity-driven separation of early-formed zoned minerals and, subsequently, by local saturation in the border zones of growing feldspar and apatite crystals. Slow diffusion in the phosphorus-rich magma pockets favoured the local saturation and simultaneous crystallization of apatite and feldspars in a crystal-ladden melt.  相似文献   

Cu- and Mn-bearing tourmalines from Brazil and Mozambique: crystal structures, chemistry and correlations     

Andreas Ertl  Gerald Giester  Ulrich Schüssler  Helene Brätz  Martin Okrusch  Ekkehart Tillmanns  Hermann Bank 《Mineralogy and Petrology》2013,107(2):265-279

Cu- and Mn-bearing tourmalines from Brazil and Mozambique were characterised chemically (EMPA and LA-ICP-MS) and by X-ray single-crystal structure refinement. All these samples are rich in Al, Li and F (fluor-elbaite) and contain significant amounts of CuO (up to ~1.8 wt%) and MnO (up to ~3.5 wt%). Structurally investigated samples show a pronounced positive correlation between the <Y-O> distances and the (Li + Mn²⁺ + Cu + Fe²⁺) content (apfu) at this site with R ² = 0.90. An excellent negative correlation exists between the <Y-O> distances and the Al₂O₃ content (R ² = 0.94). The samples at each locality generally show a strong negative correlation between the X-site vacancies and the (MnO + FeO) content. The Mn content in these tourmalines depends on the availability of Mn, on the formation temperature, as well as on stereochemical constraints. Because of a very weak correlation between MnO and CuO we believe that the Cu content in tourmaline is essentially dependent on the availability of Cu and on stereochemical constraints.  相似文献   

Identification of maars and similar volcanic landforms in the West Eifel Volcanic Field through image processing of DTM data: efficiency of different methods depending on preservation state     

Nadine Seib  Jonas Kley  Georg Büchel 《International Journal of Earth Sciences》2013,102(3):875-901

The West Eifel Volcanic Field comprises 98 maars, tuff rings, and scoria rings of volcanoes younger than 700 ka. Digital Terrain Models (DTMs) allow to automatically measure morphologic parameters of volcanic edifices such as slope angles, diameters, elevations, floor, and slope surface areas. Based on their morphological characteristics, we subdivided the West Eifel volcanoes into five morphometric groups which reflect different stages of erosion. Group I, II, and IV comprise clear ring-shaped structures. The difference between these groups is that a tephra ring is well preserved in Group I, partially preserved in Group II and absent in Group IV. The original shapes of Group III maars have been lost more substantially than in Groups I, II, or IV, but they nevertheless retain a negative shape (a depression) and have characteristic channel systems, which can be used as search criteria. Maar-diatremes of Group V are eroded down to their feeder pipes and form hills. In order to locate potential volcanic depressions that are likely to be maar volcanoes, we defined common search criteria such as circular negative landforms or particular drainage system patterns for all groups except the least well-preserved Group V. These criteria were taken as the basis for further processing of the DTM data. The first processing step consisted of constructing a residual relief calculated as the difference between a filtered (smoothed) topographic surface and the original DTM data. This identifies local topographic features. We propose a method for regulating the degree of smoothing which is based on filtering of local maxima according to their distance from a surface constructed from local minima. The previously defined search criteria for Groups I to IV such as specific ranges of curvature, slope, circularity, density of the drainage network were then applied to the residual relief in order to extract maar shapes. Not all criteria work equally well for all morphological groups. Combinations of multiple search criteria therefore yield the best results and efficiently identify most known maars. They also separate some probable new, hitherto unrecognized maars from a large number of other local depressions. We also compared the erosional state of maars to their absolute ages. Published estimates of erosion rates for maars in the French Massif Central suggest a general trend of erosion rates decreasing with time elapsed since eruption. However, this cannot explain the strongly varying ages for maars of the same morphometric group (i.e., similar preservation state) in the West Eifel Volcanic Field. The spatial distribution of the morphometric groups shows some regularity. For example, strongly eroded maars are concentrated in the Gerolstein area (where maar density is highest), whereas most well-preserved maars are located east of the Eifel North–South Depression (ENSD). Most maars affected by fluvial erosion lie near the Kyll and Kleine Kyll streams. These observations suggest differential recent uplift of the West Eifel Volcanic Field, with stronger uplift occurring west of the ENSD.  相似文献   

Kinematics of the Central Taurides during Neotethys closure and collision, the nappes in the Sultan Mountains, Turkey     

Talip Güngör 《International Journal of Earth Sciences》2013,102(5):1381-1402

In the Central Taurides, the Sultan Mountains comprise in ascending order the Çimendere unit and the Ak?ehir, Do?anhisar, Çay nappes composed of metasedimentary sequences deposited from Cambrian to Tertiary. The overthrust of the Çay nappe on the Lutetian Celepta? formation representing the uppermost stratigraphic position in the Çimendere unit indicates that the latest nappe emplacement occurred during the Middle Eocene. The Oligocene and Miocene rocks are in post-tectonic facies in the west Central Taurides. The kinematic data from these nappes related to closure of the Neotethys reveal a top-NE shear sense in the northwest part and a top-SE shear sense in the southeast part of the Sultan Mountains. The Sultan Mountains are located in the north part of the Isparta Angle which was tectonically assembled by the Lycian, Hoyran–Bey?ehir–Hadim and Antalya allochthons on the Bey Da?lar? and Anamas–Akseki autochthons from the Latest Cretaceous to the Late Pliocene. The previous paleomagnetic data showed that the west and east subsections of the Isparta Angle were subjected to post-Eocene 30°–40° anticlockwise and clockwise rotations, respectively. In consideration of these paleomagnetic data, the kinematic data measured in the Sultan Mountains might be restored into approximately E–W-trending linear fabric associated with a top-E shear sense. These new kinematic data from the nappes in the Sultan Mountains disagree with the existing tectonic models that suggest N–S nappe translation over the Central Taurides during the latest Cretaceous–Middle Eocene. The alternative tectonic model for the Antalya nappes in the core of the Isparta Angle related to east–west compression suggests westward and eastward nappe emplacements on the surrounding autochthons. However, the new kinematic data presented here point consistently to a top-E shear sense in all tectonostratigraphic units in the Sultan Mountains currently located in the north part of the Anamas–Akseki autochthon.  相似文献   

Tier-based approaches for landslide susceptibility assessment in Europe   总被引：3，自引：2，他引：1  

Andreas Günther  Paola Reichenbach  Jean-Philippe Malet  Miet Van Den Eeckhaut  Javier Hervás  Claire Dashwood  Fausto Guzzetti 《Landslides》2013,10(5):529-546

In the framework of the European Soil Thematic Strategy and the associated proposal of a Framework Directive on the protection and sustainable use of soil, landslides were recognised as a soil threat requiring specific strategies for priority area identification, spatial hazard assessment and management. This contribution outlines the general specifications for nested, Tier-based geographical landslide zonings at small spatial scales to identify priority areas susceptible to landslides (Tier 1) and to perform quantitative susceptibility evaluations within these (Tier 2). A heuristic, synoptic-scale Tier 1 assessment exploiting a reduced set of geoenvironmental factors derived from common pan-European data sources is proposed for the European Union and adjacent countries. Evaluation of the susceptibility estimate with national-level landslide inventory data suggests that a zonation of Europe according to, e.g. morphology and climate, and performing separate susceptibility assessments per zone could give more reliable results. To improve the Tier 1 assessment, a geomorphological terrain zoning and landslide typology differentiation are then applied for France. A multivariate landslide susceptibility assessment using additional information on landslide conditioning and triggering factors, together with a historical catalogue of landslides, is proposed for Tier 2 analysis. An approach is tested for priority areas in Italy using small administrative mapping units, allowing for relating socioeconomic census data with landslide susceptibility, which is mandatory for decision making regarding the adoption of landslide prevention and mitigation measures. The paper concludes with recommendations on further work to harmonise European landslide susceptibility assessments in the context of the European Soil Thematic Strategy.  相似文献   

The Gradenbach Observatory—monitoring deep-seated gravitational slope deformation by geodetic, hydrological, and seismological methods     

E. Brückl  F. K. Brunner  E. Lang  S. Mertl  M. Müller  U. Stary 《Landslides》2013,10(6):815-829

The Gradenbach mass movement (GMM) is an example of DGSD (deep-seated gravitational slope deformation) in crystalline rocks of the Eastern Alps (12.85°E, 47.00°N). The main body of the GMM covers an area of 1.7 km² and its volume is about 120?×?10⁶ m³. A reconstruction of the deformation history yields a mean displacement of?～?22 m from 1962 to 2011. In 1965/66, 1975, 2001, and 2009 high sliding velocities, exceeding several meters per year, interrupt the quasi-stationary periods of slow movement (≤0.3 m/year). Since 1999 the displacement of the main body of the GMM has been observed by GPS. Time series of extensometer readings, precipitation, snow cover water equivalent, water discharge, and hydrostatic water level observed in boreholes were re-processed and are presented in this paper. Continuous recording of seismic activity by a seismic monitoring network at the GMM began in the summer of 2006. Deformation has been monitored since 2007 by an embedded strain rosette based on fiber optics technology and a local conventional geodetic deformation network. The velocity of the GMM could be modeled to a large extent by a quantitative relation to hydro-meteorological data. During the phase of high sliding velocity in spring 2009, the seismic activity in the area increased significantly. Several types of seismic events were identified with some of them preceding the acceleration of the main body by about 6 weeks. The potential inherent in the Gradenbach Observatory data to supply early warning and hazard estimation is discussed.  相似文献   

Seasonality in low latitudes during the Oxfordian (Late Jurassic) reconstructed via high-resolution stable isotope analysis of the oyster Actinostreon marshi (J. Sowerby, 1814) from the Kachchh Basin, western India     

Matthias Alberti  Franz T. Fürsich  Dhirendra K. Pandey 《International Journal of Earth Sciences》2013,102(5):1321-1336

A high-resolution stable isotope (δ¹⁸O, δ¹³C) analysis of a specimen of the oyster Actinostreon marshi (J. Sowerby, 1814) from the Lower Oxfordian of the Kachchh Basin in western India was used to reconstruct average seasonal temperatures over a consecutive time interval of 10 years. The recorded temperatures during this period varied around a mean of 13 °C (maximum: 15.1 °C; minimum: 11.4 °C) with a generally low seasonality between 1 and 3 °C. Such weak seasonal changes can be expected from a subtropical palaeolatitude between 25° and 30°S. However, the low average temperatures are in contrast to studies on broadly contemporaneous fossils from Europe and the southern Malagasy Gulf which point to much warmer conditions in these areas. It is therefore proposed that the low temperatures in the Kachchh Basin are caused by upwelling currents which influenced the north-western coast of India during the Late Jurassic.  相似文献   

Landfill site selection and landfill liner design for Ankara, Turkey   总被引：2，自引：1，他引：1  

Gözde Pınar Yal  Haluk Akgün 《Environmental Earth Sciences》2013,70(6):2729-2752

Considering the high population growth rate of Ankara, it is inevitable that landfill(s) will be required in the area in the near future to sustain the sanitary waste disposal needs of the city. The main scope of this study is to select alternative landfill sites for Ankara based on the growing trends of Ankara toward the northwest, particularly toward the Sincan municipality, and to eventually select the best alternative through utilizing multi-criteria decision making. Landfill site selection was carried out utilizing Geographic Information System (GIS) and Multi-Criteria Decision Analysis. A number of criteria, namely, settlement, slope, proximity to roads, geology, availability and proximity of landfill containment material (i.e., clay for composite lining system), suitability for agriculture, erosion, vegetation cover and lineament system were gathered in a GIS environment. Each criterion was assigned a weight value by applying the Pairwise Comparison Method and the Analytical Hierarchy Method. In order to choose the best alternative, the Technique for Order Preference by Similarity to the Ideal Solution, which is regarded as an ideal point method, was applied and a landfill site was selected. The geotechnical properties of the so-called “Ankara clay” that shows widespread distribution in Ankara were reviewed and assessed for its suitability as a compacted clay liner.  相似文献   

Investigating hydrological drivers of nitrate export dynamics in two agricultural catchments in Germany using high-frequency data series   总被引：1，自引：1，他引：0  

Marc Schwientek  Karsten Osenbrück  Matthias Fleischer 《Environmental Earth Sciences》2013,69(2):381-393

In this study near-continuous time series of nitrate, electrical conductivity, and discharge were used to identify the dominating hydrological mechanisms that control nitrate export dynamics in two agricultural catchments. The main goal was to assess relationships between contrasting event based as well as long-term nitrate transport behaviour and catchment hydrology. Data records were obtained from online probes that allow field based high-frequency analyses over long time periods. The catchments of the Ammer River (southwestern Germany) and the Weida River (eastern Germany) are similar with respect to size (~100 km²), morphology, and climate and are dominated by agricultural use. Main differences are the stronger urbanization and the occurrence of karstic rocks in the Ammer catchment. Nitrate concentrations are high in water of both streams and range mostly between 20 and 50 mg l^?1. Nitrate export in the Ammer catchment is dominated by baseflow and a minor second, diluting runoff component generated in urbanized areas. In contrast, nitrate dynamics of the Weida catchment is governed by the interplay of at least three runoff components, while the largest amount of nitrate is mobilized intermittently by a delayed fast component generated in the catchment’s soils during wet conditions. These interpretations, derived with one online probe at the outlet of each catchment, are well in line with the former modeling results. This study shows that high-resolution data obtained by online techniques offers a large potential to improve the conceptualization of dominating flow and transport processes at catchment scales at relatively low costs and effort.  相似文献   

WESS: an interdisciplinary approach to catchment research     

Olaf Kolditz  Hermann Rügner  Peter Grathwohl  Peter Dietrich  Thilo Streck 《Environmental Earth Sciences》2013,69(2):313-315

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