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71.
The Karalar galena-barite deposits are typical examples of the carbonate-hosted barite-galena deposits widely occurring in
the Central Tauride Belt. These deposits are located in Permian limestones as ore veins along fault zones that are discordant
to the bedding planes and as thin veinlets within hardly brecciated bottom zones of Permian limestones. The ore deposits contain
mainly barite and galena and small amounts of sphalerite, pyrite, fahlore, limonite, quartz, and calcite. Barites occur during
the earlier episode of mineralization and were mylonitized before the formation of galena. Galena and other minerals occur
epigenetically with barite along porous zones between brecciated barite crystals and are especially abundant in the hardly
mylonitized zones. Fluid inclusion studies indicate that the ore deposits of the area were developed by hydrothermal fluids
with following characteristics: they contained NaCl, CaCl2, and MgCl2; the salinity of the fluids was relatively high and their temperature was low during the crystallization of barites in the
earlier episode of mineralization; and the salinity of the fluids decreased and their temperature increased during the crystallization
of sulfide minerals through the later episode of mineralization. δ18O and the δD results indicate that the water in the mineralizing fluid was of meteoric origin. The deposits were formed by
deep meteoric water circulating through marine sediments. Shallow circulating and slightly warmed fluids dissolved Ba and
sulfate from marine sediments of the basement and transported them to the mineralization environment during the early episode,
while deep circulating and more heated fluids dissolved Pb, Zn, and other elements from the basement and reached the environment
during the later episode of mineralization.
The text was submitted by the authors in English. 相似文献
72.
73.
Erdal Dolu Erkan Gökaşan Engin Meriç Mustafa Ergin Tolga Görüm Hüseyin Tur Berkan Ecevitoğlu Niyazi Avşar Muhittin Görmüş Fatmagül Batuk Buğser Tok Oktay Çetin 《Geo-Marine Letters》2007,27(6):355-381
The Quaternary evolution of the Gulf of İzmit, situated on the tectonically active North Anatolian Fault Zone (NAFZ), was
investigated using seismic reflection, paleontologic, and sediment textural data. On the basis of seismic stratigraphic and
sedimentologic-paleontologic interpretations, four depositional units were distinguished within the Plio-Quaternary sequence
of the Gulf of İzmit. According to these data, Plio-Quaternary deposits supplied from the northern terrestrial area started
to accumulate during a progradational phase, in a south-facing half-graben. A coarse-grained sedimentary unit prograding into
the gulf from the south since 200 ka b.p. indicates a dramatic variation in the evolution of the gulf, with the initiation of a new strike-slip fault of the NAFZ
and a corresponding uplift of the Armutlu Peninsula in the south of the gulf. During the evolution of this fault from a wide
shear zone consisting of right-stepped strike-slip faults and pull-apart basins to a localized principal fault zone, sediments
were deposited under the influence of northerly prograding terrestrial and shallow-marine conditions due to relative sea-level
fluctuations in the Marmara Sea. During this period, the Gulf of İzmit was invaded mainly by Mediterranean and partly by Black
Sea waters. In the latest glacial period, shallow areas in the gulf became subaerially exposed, whereas the central and western
sub-basins of the gulf turned into lakes. The present evolution of the Gulf of İzmit is controlled by the after effects of
the new rupture of the NAFZ and the estuarine nature of the gulf environment. 相似文献
74.
Using the continuation method we prove that the circular and the elliptic symmetric periodic orbits of the planar rotating
Kepler problem can be continued into periodic orbits of the planar collision restricted 3-body problem. Additionally, we also
continue to this restricted problem the so called “comet orbits”.
An erratum to this article can be found at 相似文献
75.
Inorganic industrial waste landfills have the potential to contaminate subsurface groundwater supplies through migration of leachates down to the water table and into groundwater aquifers, despite the use of compacted low permeability clay or polyethene liners. This paper aims the removal of Cu2+ and Zn2+ in the leachate from an industrial waste landfill using natural materials (natural zeolite, expanded vermiculite, pumice, illite, kaolinite, and bentonite) as a liner material. Cu2+ and Zn2+ concentrations for all treatments decreased during the process. Of all the different natural materials, natural zeolite, expanded vermiculite and pumice, with bentonite, were effective in removing Cu2+ and Zn2+ present in the leachate. However, the use of illite and kaolinite with bentonite as liner materials could be of disadvantage in Cu2+ and Zn2+ removal from leachate. The adsorption kinetic models were also tested for the validity. The second order kinetics with the high correlation coefficients best described adsorption kinetic data. 相似文献
76.
Samir Belabbès Mustapha Meghraoui Ziyadin Çakir Youcef Bouhadad 《Journal of Seismology》2009,13(4):421-432
We study the surface deformation associated with the 22 December 1999 earthquake, a moderate sized but damaging event at Ain
Temouchent (northwestern Algeria) using Interferometric Satellite Aperture Radar images (InSAR). The mainshock focal mechanism
solution indicates reverse faulting with a NE–SW trending rupture comparable to other major seismic events of this section
of the Africa–Eurasia plate boundary. Previously, the earthquake fault parameters were, however, poorly known because no aftershocks
were precisely determined and no coseismic surface ruptures were observed in the field. Using a pair of ERS data with small
baseline and short temporal separation in the ascending orbit we obtained an interferogram that shows the coseismic surface
displacement field despite poor coherence. The interferogram measures four fringes and displays an ellipse-shaped lobe with
∼11 cm peak line-of-sight displacement. The elastic modeling using a boundary element method (Poly3Dinv) indicate coseismic
slip reaching up to 1 m at 5 km depth on the N 57° E trending, dipping 32° NW Tafna thrust fault. The geodetic estimate of
seismic moment is 4.7 × 1017 N m. (Mw 5.7) in is good agreement with seismological results. The elliptical shape of the surface displacement field coincides
with the NE–SW trending Berdani fault-related fold. The consistency between the geological observations and InSAR solution
shed light on the precise earthquake location and related Tafna fault parameters. 相似文献
77.
Tekeli-Yeşil Sıdıka Dedeoğlu Necati Braun-Fahrlaender Charlotte Tanner Marcel 《Natural Hazards》2011,59(1):427-446
Awareness and perception of risk are among the most crucial steps in the process of taking precautions at individual level
for various hazards. In this study, we investigated the factors affecting better knowledge and greater risk perception about
earthquakes among residents of Istanbul. A field survey was carried out, and a total of 1,123 people were interviewed in two
districts of Istanbul with different seismic risk levels and from three (low, moderate and high) socio-economic levels (SEL).
The findings showed that although the level of knowledge regarding earthquakes and preparedness for them was promising, it
could be improved. The results indicated that future preparedness programmes should target people with lower educational and
socio-economic levels. The media were the leading source of information among the respondents. Location of the home was a
strong influence on individuals having above average earthquake knowledge and even more on high risk perception. Socio-economic
parameters (educational level, economic status, SEL of the sub-district and tenure of the home), gender and attitude score
were other factors influencing greater risk perception with regard to earthquakes. 相似文献
78.
79.
Ahmet Güllü Ercan Yüksel Cem Yalçın A. Anıl Dindar Hasan Özkaynak Oral Büyüköztürk 《地震工程与结构动力学》2019,48(1):27-45
Input energy is the principal component of the energy balance equation. It is beneficial to determine, through its components, how the recoverable and irrecoverable energies are distributed within the structural elements. Several equations and attenuation relations to define mass-normalized input energy spectra exist in the literature. They are mainly proposed for elastic systems subjected to far-fault EQs. There is a lack of experimental verification of these proposed spectra. In this paper, experimental assessment was performed to the existing spectra, and further improvements were accomplished. For this purpose, steel cantilever columns were tested on the shake table for two specific historical EQs coincidently having similar spectral acceleration values. Based on the experimental results, a three-part mass-normalized relative input energy spectrum was formulated including soil type, EQ (corner period, intensity, duration, spectral acceleration, and velocity), and structural behavioral characteristics (period and structural damping). The proposed input energy spectrum was experimentally calibrated and numerically validated for various EQs featuring near- and far-field types. Analytical and experimental comparisons were made between the previously developed spectrum and the newly proposed one. The validation studies and the statistical evaluations exposed that the proposed spectrum yielded better agreement with the experimental and numerical results. 相似文献
80.
JEAN‐FRANÇOIS GHIENNE FLAVIA GIRARD JULIEN MOREAU JEAN‐LOUP RUBINO 《Sedimentology》2010,57(5):1175-1198
Climbing dune‐scale cross‐statification is described from Late Ordovician paraglacial successions of the Murzuq Basin (SW Libya). This depositional facies is comprised of medium‐grained to coarse‐grained sandstones that typically involve 0·3 to 1 m high, 3 to 5 m in wavelength, asymmetrical laminations. Most often stoss‐depositional structures have been generated, with preservation of the topographies of formative bedforms. Climbing‐dune cross‐stratification related to the migration of lower‐flow regime dune trains is thus identified. Related architecture and facies sequences are described from two case studies: (i) erosion‐based sandstone sheets; and (ii) a deeply incised channel. The former characterized the distal outwash plain and the fluvial/subaqueous transition of related deltaic wedges, while the latter formed in an ice‐proximal segment of the outwash plain. In erosion‐based sand sheets, climbing‐dune cross‐stratification results from unconfined mouth‐bar deposition related to expanding, sediment‐laden flows entering a water body. Within incised channels, climbing‐dune cross‐stratification formed over eddy‐related side bars reflecting deposition under recirculating flow conditions generated at channel bends. Associated facies sequences record glacier outburst floods that occurred during early stages of deglaciation and were temporally and spatially linked with subglacial drainage events involving tunnel valleys. The primary control on the formation of climbing‐dune cross‐stratification is a combination between high‐magnitude flows and sediment supply limitations, which lead to the generation of sediment‐charged stream flows characterized by a significant, relatively coarse‐grained, sand‐sized suspension‐load concentration, with a virtual absence of very coarse to gravelly bedload. The high rate of coarse‐grained sand fallout in sediment‐laden flows following flow expansion throughout mouth bars or in eddy‐related side bars resulted in high rates of transfer of sands from suspension to the bed, net deposition on bedform stoss‐sides and generation of widespread climbing‐dune cross‐stratification. The later structure has no equivalent in the glacial record, either in the ancient or in the Quaternary literature, but analogues are recognized in some flood‐dominated depositional systems of foreland basins. 相似文献