排序方式： 共有41条查询结果，搜索用时 203 毫秒
1.
T. M. Zlobina V. A. Petrov V. Yu. Prokofiev A. A. Kotov K. Yu. Murashov A. A. Wolfson 《Doklady Earth Sciences》2016,470(2):1050-1055
Syn-ore centroid type deformations that produced unusual structural assemblages are identified in the Uryakh ore field. The regularities of the deformation process comparable to a mechanism of the centroid-type seismic focus are established. The results of studying fluid inclusions suggest that the pressure—temperature parameters of the system correspond to conditions typical of the seismic regime. A model of formation of structural assemblages in a centroid-type dynamic regime with the participation of fluids is proposed for the first time. 相似文献
2.
Pertsev A. N. Bortnikov N. S. Prokofiev V. Yu. Aranovich L. Ya. Ageeva O. A. Beltenev V. E. Zhilicheva O. M. Kovalchuk E. V. 《Doklady Earth Sciences》2018,480(1):661-665
New data on local mineral associations and the microheterogeneity of minerals and fluid inclusions in gabbro were obtained for the gabbro–peridotite oceanic core complex with a long-lived detachment fault controlling the hydrothermal activity. It is assumed that the hydrothermal hydrogen-bearing fluid with a NaCl content of >30 wt % is formed in the seawater/harzburgite (~1/5) reaction of serpentinization. The brine residual after serpentinization interacted with gabbro at the final stages of crystallization of an intrusion and assimilated some components (K, REEs, and Ba) from the residual melt. The interaction was resulted in metamorphic transformations of gabbro at decreasing temperature below 500°C. The reaction of the decomposition of magmatic titanomagnetite with the transition of iron reduced to Fe2+ into newly formed chlorinebearing amphibole at 540–450°C and logf(O2) from–20 to–24 is shown.
相似文献3.
N. G. Lyubimtseva N. S. Bortnikov S. E. Borisovsky V. Yu. Prokofiev O. V. Vikent’eva 《Geology of Ore Deposits》2018,60(2):93-120
The mineral assemblages, mode of occurrence, and chemical compositions of coexisting fahlore and sphalerite from the Darasun gold deposit have been described. Three generations of fahlore and three generations of sphalerite have been recognized. The FeS content in sphalerite coexisting with fahlore ranges from 0.8 to 9.4 mol %. The complete solid solution series Fe-tetrahedrite–Zn-tetrahedrite–Fe-tennantite–Zn-tennantite reflected in Sb/(Sb + As) and Fe/(Fe + Zn) ratios ranging from 0 to 0.97 and from 0.07 to 1.00, respectively, with a predominant negative relationship between these ratios has been identified for the first time at the deposit. Stepped, oscillatory, and combined stepped-oscillatory growth zonings within fahlore grains and heterogeneous aggregates of fahlore have been found. Fahlore is enriched in As with respect to Sb, and Zn-tetrahedrite is followed by Fe- and Zn-tennantite from early to late generation; Zn-tetrahedrite is followed by Fe-tennantite in zoned grains and overgrown rims; sphalerite crystallized at decreased temperature and sulfur fugacity. The evolution of the chemical composition of fahlores was caused by the evolving temperature, fluid salinity, and conditions of metal migration. 相似文献
4.
Experiments were conducted on the fragmentation of analogue low-strength porous material (plastiprin) by rapid decompression
in a shock-tube-type apparatus. The porous samples (length=365 mm, cross-section dimensions 40×40 mm) pressurized by air to
pressures up to 0.9 MPa, were rapidly decompressed to 0.1 MPa. Rapid decompression of samples caused fragmentation and ejection
of the fragmentation products into a large volume tank. The process of analogue material fragmentation was documented using
high-speed cinematography and dynamic pressure measurements. The duration of the fragmentation event is significantly shorter
than that of the ejection event. The fragmentation of material precedes the acceleration of fragments. As a result of fragmentation,
sub-parallel fractures are generated. The characteristic fragment size decreases as the initial pressure differential increases.
The ejected fragments obtain velocities of 60 m/s. The mechanisms of material fragmentation during unloading and fragmentation
wave propagation are discussed. The experimental results provide insight into the fragmentation dynamics of highly viscous
magmas in which brittle failure at high strain rate is possible.
Received: 23 July 1997 / Accepted: 23 November 1997 相似文献
5.
Lyubimtseva N. G. Bortnikov N. S. Borisovsky S. E. Vikent’eva O. V. Prokofiev V. Yu. 《Geology of Ore Deposits》2019,61(6):530-548
Geology of Ore Deposits - Heterogeneous rhythmic–zonal aggregates of tennantite-IV partly or completely replacing early homogeneous Zn-tetrahedrite-I grains and euhedral... 相似文献
6.
E. I. Yartsev I. V. Vikentyev V. Yu. Prokofiev 《Moscow University Geology Bulletin》2017,72(2):132-138
The Dzhusinskoe pyrite–polymetallic deposit is characterized by an abundant concentration of dykes of basic and intermediate rocks. Thermal metamorphism of ore-host rocks and the recrystallization of ore minerals are associated with the intrusion of post-ore dykes. A regular increase in the homogenization temperature from 156° at a distance from a dyke to 287–305°C in the contact zone was established. Highly saline (6.4–15.7 wt % NaCl eq.) CO2–H2O–NaCl fluids under high pressure (up to 1500 bar) can be associated with the processes of contact and regional metamorphism. 相似文献
7.
D. V. Kovalenko V. B. Naumov V. Yu. Prokofiev O. A. Ageeva O. A. Andreeva E. V. Kovaltchuk K. G. Erofeeva N. Yu. Ugryumova 《Petrology》2017,25(1):66-86
Original authors’ data on the mineralogy and composition of melt inclusions in two samples show that the Early Eocene magmatic rocks at Cape Khairyuzova were formed by mixing melts of mafic, intermediate, and acid composition, which were derived from different sources. The mafic melt was rich in MgO, and its temperature was 1100–1150°C. The temperature of the acid melt varied from 1070 to 1130°C. The melts are also different in concentrations of trace elements and in their ratios. All three melt types are enriched in LILE and LREE and depleted in HFSE and were likely derived in suprasubductional environments. The mafic and intermediate magmas were formed by melting a mantle wedge and subsequent fractionation of the melts. The acid melts could be formed by melting crustal rocks when they were overheated in the newly formed orogen of significant thickness. When ascending, the mantle melts could mix in variable proportions with acid melts in crustal chambers. 相似文献
8.
V. V. Aristov S. G. Kryaghev O. B. Ryzhov A. A. Volfson V. Yu. Prokofiev N. V. Sidorova A. A. Sidorov 《Doklady Earth Sciences》2017,476(1):986-991
The peculiarities of fluid inclusions; the O and C isotope composition of host rocks, vein minerals, and inclusions; and the S and Pb isotope composition of sulfides allowed us to distinguish two groups of fluids with a similar temperature, salinity, and source of the aqueous part produced upon metagenesis and mobilized during collisional events. Quartz-A precipitates from the CO2–H2O hydrocarbonate–Na fluid with a salinity of 7–10 wt % eq. NaCl at a depth of ～6 km (290–340°C, 1550 bar). Regeneration of quartz (quartz-C), precipitation of quartz-B, and quartz-AB with carbonate and chlorite occurred at a depth from 3.5 to 1.5 km (250–380°C, 1250–900–350 bar) from CO2–CH4–N hydrous sulfate–hydrocarbonate Na–Mg fluids with Cl–, Ca, and K and a salinity of 5–10 wt % eq. NaCl, and a wide variety of impurities. The localization of veins in sinistral shear dislocations and strong heterogeneity in the P–T conditions allow us to explain the formation of fluid-2 by the postcollisional events. 相似文献
9.
Firsova Alena D. Chebykin Eugene P. Kopyrina Liubov I. Rodionova Elena V. Chensky Dmitry A. Gubin Nikita A. Panov Vsevolod S. Pogodaeva Tatyana V. Bukin Yurij S. Suturin Alexandr N. Likhoshway Yelena V. 《Journal of Paleolimnology》2021,66(4):407-437
Journal of Paleolimnology - In this study, radiocarbon-dated geochemical and diatom records from Lake Vorota located within the informal meteorological ‘pole of cold’ of the northern... 相似文献
10.
In this paper a new seismic design procedure for Reinforced Concrete (R/C) structures is proposed—the Rigid‐Plastic Seismic Design (RPSD) method. This is a design procedure based on Non‐Linear Time‐ History Analysis (NLTHA) for systems expected to perform in the non‐linear range during a lifetime earthquake event. The theoretical background is the Theory of Plasticity (Rigid‐Plastic Structures). Firstly, a collapse mechanism is chosen and the corresponding stress field is made safe outside the regions where plastic behaviour takes place. It is shown that this allows the determination of the required structural strength with respect to a pre‐defined performance parameter using a rigid‐plastic response spectrum, which is characteristic of the ground motion alone. The maximum strength demand at any point is solely dependent on the intensity of the ground motion, which facilitates the task of distributing required strength throughout the structure. Any artificial considerations intended to adjust results according to empirical observations are avoided, which, from a conceptual point of view, is considered to be an advantage over other simplified design procedures for seismic design. The procedure is formulated using a step‐by‐step format followed by a design example of a 4‐storey‐R/C‐plane‐frame. Results are compared with refined NLTHA and found to be extremely encouraging. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献