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551.
552.
Deciphering factors controlling trace element distribution in the soils of Karaduvar industrial-agricultural area (Mersin,SE Turkey) 总被引:1,自引:0,他引:1
Cüneyt Güler Musa Alpaslan Mehmet Ali Kurt Abidin Temel 《Environmental Earth Sciences》2010,60(1):203-218
In this study, 30 topsoil samples were collected from Karaduvar area (Mersin, SE Turkey) where at present various industrial
and agricultural activities are occurring. Using a five-step ultrasound-assisted sequential extraction (UASE) procedure, trace
elements in soil samples were partitioned into the following: (1) soluble-exchangeable; (2) bound to carbonates; (3) bound
to Fe- and Mn-oxides; (4) bound to organic matter and sulfide compounds, and (5) residual fraction. Concentrations of 11 trace
elements in the extracts were determined using ICP-MS. Total concentrations ranged between (in mg kg−1) 3.35 and 7.26 for As; 1.18 and 3.96 for Cd; 10.76 and 20.26 for Co; 37.99 and 63.48 for Cr; 18.55 and 243.1 for Cu; 338.7
and 565.6 for Mn; 4.42 and 6.44 for Mo; 148 and 279.3 for Ni; 10.12 and 73.71 for Pb; 17.93 and 36.55 for V, and 25.46 and
331.7 for Zn. Factor analysis was applied to dataset in order to discriminate between natural and anthropogenic pollution
sources and factors controlling the spatial distribution of trace elements in the area. Results suggest that distributions
of Co, Cr, Mn, and Ni are mainly controlled by lithological factors, whereas, distributions of Cu, Pb, and Zn can be attributed
to agricultural activities such as pesticide/herbicide use and fertilizer application, as well as irrigation with petroleum
hydrocarbon-contaminated groundwater. Highest concentrations of Cd and Mo are generally observed around the diesel-fired thermal
power plant and ATAŞ refinery. Highest concentrations of As and V are generally observed at the NW sector of the area; however,
no definitive source can be designated for both of these elements. 相似文献
553.
Relative sea-level change at the time of, and since, the most recent great earthquake at the Cascadia subduction zone is estimated from intertidal sediments at three marshes on western Vancouver Island, British Columbia. We compare the elevation of the pre-earthquake surface, which is marked by a tsunami sand sheet, with the modern depositional elevation range of the sediment type upon which the sand was deposited. At a site south of the Nootka fault zone, which is the northern boundary of the subducting Juan de Fuca plate, tidal mud overlies the pre-earthquake marsh surface. The stratigraphy at this site indicates 0.2–1.6 m of coseismic submergence and 1.1 m of subsequent emergence. In contrast, two sites to the north lack obvious stratigraphic evidence for coseismic land-level change and record between 0.1 and 1.7 m of post-earthquake submergence. These results indicate a difference in tectonic environment across the Nootka fault zone and suggest that plate-boundary rupture during the last great Cascadia earthquake probably did not extend north of central Vancouver Island. 相似文献
554.
555.
Sr isotope systematics during melt generation by intrusion of basalt into continental crust 总被引:1,自引:1,他引:0
We have studied the Sr isotopic composition of partial melts of biotite granite generated experimentally and by intrusion
of basalt into the Sierra Nevada Batholith. The experiments employed large, 3-cm cubes of granite to duplicate natural grain-boundary
textures and were performed in air over the temperature interval 1000–1250 °C, to simulate basalt-induced wall rock and xenolith
melting in the shallow crust. In both the experimental and natural analogs, fusion of plagioclase + alkali-feldspar ± quartz
and biotite + plagioclase ± quartz results in the formation of colorless and brown melt (quenched to glass) respectively.
Accordant with this melting behavior, brown glasses are enriched in radiogenic Sr and MgO, FeO, CaO, and TiO2 relative to colorless glasses. These results support recent studies indicating that the isotopic compositions of crustal
melts can reflect the relative contributions of mineral phases entering the melt, rather than the isotopic composition of
the bulk source rock. In addition, we show that at shallow-crustal conditions preferential breakdown of biotite leads to initial
high-87Sr/86Sr, low-Sr concentration melts. However, as the degree of melting increases, melts become less radiogenic yet are more enriched
in elemental Sr due to loss of biotite from the restite and increased consumption of feldspars. Our results therefore suggest,
if partial melts of granitic crust segregate rapidly during episodic magmatic underplating, successive melt batches can evolve
from high-87Sr/86Sr to low-87Sr/86Sr liquids as melting progresses.
Received: 25 August 1998 / Accepted: 10 March 1999 相似文献
556.
Fine- and microstructure observations indicate bottom-intensified turbulent dissipation above rough bathymetry associated with internal wave breaking. Simple analytic representations for the depth profile of turbulent dissipation are proposed here under the assumption that the near bottom wavefield is dominated by a baroclinic tide. This scheme is intended for use in numerical models and thus captures only the gross features of detailed solutions to the energy balance of the internal wavefield. The possible sensitivity of the magnitude and vertical variability of the dissipation rate profile to various environmental parameters is discussed. An expression for the diapycnal buoyancy flux is presented that explicitly treats the difference between the height of an isopycnal above the mean bottom and the actual bottom. This returns a diapycnal velocity estimate that is consistent with both tracer observations of downwelling and a basin scale mass budget that requires upwelling. 相似文献
557.
Marotta Anna Maria Seitz Kurt Barzaghi Riccardo Grombein Thomas Heck Bernhard 《Studia Geophysica et Geodaetica》2019,63(3):321-344
Studia Geophysica et Geodaetica - Forward modelling in the space domain is a very important task in geodesy and other geosciences. From topographical or isostatic information in the form of digital... 相似文献
558.
西阿尔卑斯Zermatt-Saas洋壳深俯冲超高压变质带与我国新疆西南天山超高压变质带的比较 总被引:1,自引:0,他引:1
根据对西阿尔卑斯Zernatt-Saas带的野外地质考察及有关资料的总结,详细地介绍了西阿尔卑斯Zermatt-Saas洋壳深俯冲超高压变质带的地质概括、岩石组成和变质作用演化过程,并着重与我国新疆西南天山洋壳深俯冲超高压变质带进行了比较,探讨了这两个洋壳深俯冲超高压变质带在变质作用和地质演化方面的异同。在此基础上,总结了这两个目前世界上已知最典型的洋壳深俯冲超高压变质带的基本地质特征是都具有保存完好的洋壳岩石组合特征和较低的地热梯度。 相似文献
559.
560.
The occurrence of the invasive nonindigenous copepod Oithona davisae Ferrari and Orsi, 1984, is reported for the first time in the Aegean Sea. The data we collected in August 2017 from 14 stations along the Turkish coast of the Aegean Sea reveal the spatial distribution of O. davisae between the openning of the Dardanelles Strait in the north and the Izmir Bay in the south. The O. davisae individuals, in seven mesozooplankton samples collected from a single station, were consistently found in the inner part of the Izmir Bay from April 2015‐October 2016. The abundance of female O. davisae ranged from 4 ind./m3 in April 2015 to 31,524 ind./m3 in July 2016 and contributed to the total oithonid female population by 10.8% in April 2015 and 92.8% in September 2016. Our results show that this species is well established in the inner part of Izmir Bay and that it has become a permanent component of the copepod community in the area. 相似文献