Intermediate sulfidation epithermal gold-base metal deposits in Tertiary subaerial volcanic rocks,Sahinli/Tespih Dere (Lapseki/Western Turkey)     

Huseyin Yilmaz  Tolga Oyman  F. Nuran Sonmez  Greg B. Arehart  Zeki Billor 《Ore Geology Reviews》2010,37(3-4):236-258

Gold in the Sahinli and Tespih Dere intermediate sulfidation gold-base metal deposits in Western Turkey occurs in relatively deep epithermal quartz veins along with base metal minerals which have epithermal textures, including plumose quartz, vug infills, comb and cockade textures and matrix-supported milled breccias. The total sulfide content of the veins in the area is variable ranging from < 1% to 60% and is dominated by pyrite, galena, sphalerite and chalcopyrite. Sphalerite is Fe-poor (0.6 to 1.4 mol% FeS). Minor amounts of Ag-rich tetrahedrite are present. Primary hydrothermal alteration minerals include illite/muscovite, mixed-layer illite/smectite (11.6 Å) and clinochlore towards the east and, alunite, dickite/nacrite and pyrophyllite towards the west at Sahinli; major illite/muscovite and dickite occur at Tespih Dere and Sarioluk, respectively.Fluid inclusions in main-stage quartz at Sahinli are only liquid-rich, with homogenization temperatures ranging from 220 to 322 °C and the majority of T_h values between 250 and 300 °C. Salinity ranges from 4.3 to 6.9 wt.% NaCl equiv. First ice-melting temperatures (T_mf) between ?24.5 and ?19.0 °C indicate that the fluids were dominated by NaCl – H₂O during mineralization. The relatively higher average T_h at the Tespih Dere deposit (295 °C) is attributed to a relatively deeper level of exposure.Calculated δ¹⁸O values indicate that ore-forming hydrothermal fluids in the study area had δ¹⁸O_H2O ranging from + 1.1 to + 9.7‰ (average = 3.8‰), strongly ¹⁸O-enriched compared with present-day hydrothermal meteoric water in the area (δ¹⁸O = ?8.5‰). δD values of fluid inclusions in quartz range from ?58 to ?93‰ and δD values of clay minerals and alunite from ?40 to ?119‰. δD values from intermediate argillic alteration (average = ?68‰) in the study area are very similar to δD values of the present-day local geothermal system (average δD = ?54‰) whereas δD values from advanced-argillic alteration (average δD = ?33‰) are very different from the present-day local geothermal system.The δ³⁴S values in samples from the Sahinli and Tespih Dere deposits average ?2.9‰ for pyrite; ?3.3‰ for chalcopyrite; ?5.4‰ for sphalerite and ?7.6‰ for galena. These data are consistent with derivation of the sulfur from either igneous rocks or possibly from local wallrock.  相似文献   

Photometry of three chromospherically active stars: V340 Gem,SAO 62042 and FI Cnc     

A. Erdem  E. Budding  E. Soydugan  F. Soydugan  S.S. Doğru  D. Doğru  M. Tüysüz  A. Dönmez  H. Bakiş  Y. Kaçar  C. Çiçek  Z. Eker  O. Demircan 《New Astronomy》2009,14(2):109-120

We present a photometric study of three chromospherically active stars with long periods (V340 Gem, SAO 62042 and FI Cnc). The observations were made at the ÇOMU Observatory in 2006 and 2007. We have made initial photometric analyses of V340 Gem and SAO 62042, which are newly discovered RS CVn–type SB1 binaries, and established the photometric variations of FI Cnc, which is a single G8III active star. Photometric rotation periods of these stars were obtained by analyzing their light variations. The light variations, observed over three or more consecutive orbital cycles, were investigated by using spot models with the program SPOT. We also discussed the surface differential rotation coefficient for the primary component of the SB1 binary star SAO 62042 in this study, using our own photometric period together with an orbital period taken from the literature.  相似文献   

Assessing consistency of Chang’E-1 and SELENE reference frames using nearly-colocated laser altimetry footprint positions     

H.?Baki?IzEmail author  Y.?Q.?Chen  C.?K.?Shum  X.?L.?Ding  B.?A.?King  W.?Chen  M.?Berber 《Journal of Geodesy》2012,86(2):109-117

The consistency of the Chang’E-1 and SELENE reference frames as realized by the footprint positions of laser altimetry measurements of the lunar surface during both missions was analyzed using a global 12-parameter model for small (with respect to unity) deformations and rigid body motions. The rigid body motion and deformation parameters between the two reference frames estimated from nearly-colocated without tie measurements are found to be consistent, i.e., nearly zero for the estimates of the translations, rotations and shear parameters. However, the estimated three strain parameters, which are similar in magnitude and sign, reveal a prominent scale difference, between the Chang’E-1 and SELENE reference frames, of about 0.9 × 10⁻⁵. The scale difference can be attributed to calibration of the data sets using the known coordinates of the lunar laser ranging stations all located on the near side of the Moon.  相似文献   

Catagenetic transformations of gravelly–sandy rocks of the Taseeva Group in the Irkineevo–Chadobetsk riftogenic trough (southern Siberian Platform)     

O. V. Yapaskurt  O. V. Postnikova  V. V. Poshibaev  A. D. Iz”yurov  N. K. Danilko 《Lithology and Mineral Resources》2017,52(5):401-412

The stagewise optical and electron-microscopic analysis of the texture and mineralogy of the Upper Riphean–Lower Vendian gravelly–sandy rocks (Taseeva Group) in the Irkineevo–Chadobetsk riftogenic trough revealed a wide spectrum of secondary transformations: gravitational corrosion of allothigenic minerals, their plastic deformation, intense fracturing, and authigenic mineral formation. Traces of low-temperature hydrothermal processes were recorded. The multistage nature of authigenic mineral formation is attributed to the periodic resumption of tectonic dislocations owing to reactivation of fluid dynamics and thermal impulses ΔT.  相似文献   

Dependency of GPS positioning precision on station location     

Jiexian Wang  Bâki H. Iz  Caiping Lu 《GPS Solutions》2002,6(1-2):91-95

We analyze the dependency of the GPS positioning precision on station location in an idealized positioning environment. Using a weighting function to account for an averaged number of satellites at different latitudes, we demonstrate that GPS positioning precision for ambiguity fixed solutions reduces when the latitude increases. We also quantify that the positioning precision in the north-south direction is worse than that in the east-west direction at all latitudes using the same approach. Electronic Publication  相似文献   

Late Cenozoic stress evolution along the Karasu Valley, SE Turkey     

Semir Over  Suha Ozden  Huseyin Yilmaz 《Tectonophysics》2004,380(1-2):43-68

This study defines the Mio-Pliocene to present-day stress regime acting at the northeastern corner of the eastern Mediterranean region along the Karasu Valley (i.e., the Amanos Range), taking in the Antakya, Osmaniye and Kahramanmaras provinces. The inversion slip vectors measured on fault planes and chronologies between striations indicate that the stress regime varied from transpressional initially to transtensional, having consistent NW- and NE-trending σ_Hmax (σ₁) and σ_Hmin (σ₃) axes, respectively; there are significantly different mean stress-ratio (R_m) values however. The older mean stress state is characterized by N151±11°E-trending σ₁ and N59±12°E-trending σ₃ axes, and by a mean arithmetic R_m value of 0.76, indicating that the regional stress regime is transpressional. The younger stress regime is characterized by N154±8°E-trending σ₁ and N243±8°E-trending σ₃ axes, and by a mean arithmetic R_m value of 0.17, indicating a transtensional character for this regional stress regime. The low R values of the stress deviators related to the recent stress state reflect normal-component slips. The earthquake focal mechanism inversions confirm that the younger stress regime continues into the Recent. The inversion identifies a transtensional stress regime representing strike-slip and an extensional stress state with a consistent NE-trending σ_Hmin (σ₃) axis. These stress states are characterized by N66°E and N249°E-trending σ₃ axes, respectively. Both significant regional stress regimes induce left-lateral displacement along the southern part of the East Anatolian Fault (EAF, or Amanos Fault). The temporal change, probably in Quaternary time, within the regional stress regime—from transpression to transtension—resulted from the coeval influences of subduction processes in the west–southwest (i.e., along the Cyprus arc), continental collision in the east, and westward escape of the Anatolian block.  相似文献   

Origin of petroliferous bitumen from the Büyük Menderes–Gediz geothermal graben system,Denizli – Sarayköy,western Turkey     

Kadir Gürgey  Bernd R.T. Simoneit  Zühtü Batı  İsmail H. Karamanderesi  Baki Varol 《Applied Geochemistry》2007

The KB-5 well is located at the intersection of the geothermally active Menderes and Gediz graben systems in western Turkey. Significant volumes of “petroleum-like material” (PLM) with its associated thermal water (120 °C) erupted onto the surface during drilling from a depth of 120–132 m (i.e., from the claystone and marl-rich Early to Middle Pliocene Kolonkoya formation). The purpose of this paper is: (1) to characterize this PLM, (2) to assess the source characteristics from which the PLM was likely generated, and (3) to recognize the generation mechanism considering the geothermal-gradual versus the hydrothermal-rapid processes. Analytical organic geochemistry using thin layer chromatographic separation followed by gas chromatography–mass spectrometry (GC–MS) was carried out.  相似文献   

Sedimentary facies, depositional environments and palaeogeographic evolution of the Neogene Denizli Basin, SW Anatolia, Turkey   总被引：2，自引：0，他引：2  

Hülya Alçiçek  Baki Varol 《Sedimentary Geology》2007,202(4):596-637

The Denizli Basin (southwestern Anatolia, Turkey) contains a record of environmental changes dating since the Early Miocene. Detailed facies analysis of the Neogene formations in this half-graben enables us to document successive depositional regimes and palaeogeographic settings. Sedimentation commenced in the Early Miocene with the deposition of alluvial-fan and fluvial facies (K?z?lburun Formation). At this stage, alluvial fans sourced from elevated areas to the south prograded towards the basin centre. The Middle Miocene time saw the establishment of marginal lacustrine and wetland environments followed by the development of a shallow lake (Sazak Formation). The uppermost part of this unit consists of evaporitic saline lake and saline mudflat facies that grade upward into brackish lacustrine deposits of Late Miocene-Pliocene age (Kolankaya Formation). The lake became shallower at the end of the Pliocene time, as is indicated by expansion shoreface/foreshore facies. In the Early Quaternary, the Denizli Basin was transformed into a graben by the activation of ESE-trending normal faults. Alluvial fans were active at the basin margins, whereas a meandering river system occupied the basin central part.Oxygen isotope data from carbonates in the successive formations show an alternation of wetter climatic periods, when fresh water settings predominated, and very arid periods, when the basin hosted brackish to hypersaline lakes. The Neogene sedimentation was controlled by an active, ESE-trending major normal fault along the basin's southern margin and by climatically induced lake-level changes. The deposition was more or less continuous from the Early Miocene to Late Pliocene time, with local unconformities developed only in the uppermost part of the basin-fill succession. The unconformable base of the overlying Quaternary deposits reflects the basin's transformation from a half-graben into a graben system.  相似文献   

Comprehensive study on automation of toxic gas measurement     

Murat Ayaz  Erkutay Tasdemirci  Huseyin Yuksel  Volkan Aygul 《Arabian Journal of Geosciences》2018,11(22):725

The condition of the ambient air must be continuously checked to detect hazardous gas leakage and ensure the safety of employees in hazardous gas production and storage areas. Detection and elimination of hazardous gas leaks can be done with various complex measurement, safety, and disposal systems. These measurement systems consist of different types of sensor and require control and monitoring system. This leads to high investment and operating costs. In this study, semi-continuous measurement system automation with a single set of sensors working by taking air samples from different points over specific periods has been designed to reduce investment, operation, and maintenance repair costs. In the design, the measurement points are divided into zones and codes in the automation system. Thus, it is aimed to keep a constant record of what the air sample is coming from and what its content is. As a result, it has been determined that it is possible to establish a measurement and automation system similar to existing hazardous gas measurement systems with less investment and operating costs. The proposed automation system has been applied in the industrial storage area. In addition, a cost analysis has been performed and compared with conventional systems.  相似文献   

Tectonic evolution of the northern shelf of the Marmara Sea (Turkey): interpretation of seismic and bathymetric data   总被引：1，自引：1，他引：0  

Huseyin Tur  Nihan Hoskan  Gulten Aktas 《Marine Geophysical Researches》2015,36(1):1-34

  相似文献