Synthetic fluid inclusions. XV. TEM investigation of plastic flow associated with reequilibration of fluid inclusions in natural quartz   总被引：1，自引：0，他引：1  

Maxim O. Vityk  Robert J. Bodnar  Jean-Claude Doukhan 《Contributions to Mineralogy and Petrology》2000,139(3):285-297

The nature and abundance of dislocations in quartz surrounding fluid inclusions were studied to obtain a better understanding of processes associated with fluid inclusion reequilibration. Synthetic fluid inclusions containing 10 wt% NaCl aqueous solution were formed in three samples at 700 °C and 5 kbar. One of the samples was quenched along an isochore to serve as a reference sample. The other two samples were quenched along a P-T path that generated internal pressures in excess of the confining pressure. The two samples were held at the final reequilibration P-T conditions of 625 °C and 2 kbar for 30 and 180 days, respectively. Following the experiments, microstructures associated with fluid inclusions were examined with the TEM. Quartz in healed fractures in the reference sample that was quenched isochorically shows a moderate dislocation activity. Quartz adjacent to reequilibrated fluid inclusions in the other two samples, however, showed a marked increase in dislocation activity compared to the un-reequilibrated sample. Deformation of the inclusion walls occurred anisotropically by expansion of mobile dislocations in their slip systems. Dislocation expansion was controlled by glide in the rhombohedral planes {1 0 1 1} that was restricted to narrow zones (≤3 μm) in the immediate vicinity of the fluid inclusion walls outside of the healed fracture plane. These plastic zones were observed after both short term (30 days) and long term (180 days) experiments and are attributed to hydrolytic weakening of quartz around fluid inclusions owing to diffusion of water into the quartz matrix during the experiment. The close spatial association of submicroscopic water bubbles with dislocations, and the rarity of water bubbles in the reference sample, show clearly that in both the 30 and 180 day experiments reequilibration involves water loss from the fluid inclusions. Our results indicate that synthetic fluid inclusions in this study recover (chemically and volumetrically), even at relatively fast experimental loading rates, such that internal stresses never reach the point of brittle failure. The driving force for fluid inclusion deformation involves two related mechanisms: plastic deformation of hydrolytically weakened wet quartz in the healed fracture, and water leakage associated with preexisting and strain-induced dislocations. Received: 5 May 1998 / Accepted: 10 February 2000  相似文献   

Electrochemical Degradation of Triketone Herbicides and Identification of Their Main Degradation Products          下载免费PDF全文

Milica Jović  Dragan Manojlović  Dalibor Stanković  Uroš Gašić  Dejan Jeremić  Ilija Brčeski  Goran Roglić 《洁净——土壤、空气、水》2015,43(7):1093-1099

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Crustal Architecture of the Inverted Central Lapland Rift Along the HUKKA 2007 Profile     

Timo Tiira  Tomasz Janik  Elena Kozlovskaya  Marek Grad  Annakaisa Korja  Kari Komminaho  Endre HegedŰs  Csaba Attila Kovács  Hanna Silvennoinen  Ewald BrŰckl 《Pure and Applied Geophysics》2014,171(7):1129-1152

We have studied the lateral velocity variations along a partly buried inverted paleo–rift in Central Lapland, Northern Europe with a 2D wide-angle reflection and refraction experiment, HUKKA 2007. The experiment was designed to use seven chemical explosions from commercial and military sites as sources of seismic energy. The shots were recorded by 102 stations with an average spacing of 3.45 km. Two-dimensional crustal models of variations in P-wave velocity and Vp/Vs-ratio were calculated using the ray tracing forward modeling technique. The HUKKA 2007 experiment comprises a 455 km long profile that runs NNW–SSE parallel to the Kittilä Shear Zone, a major deformation zone hosting gold deposits in the area. The profile crosses Paleoproterozoic and reactivated Archean terranes of Central Lapland. The velocity model shows a significant difference in crustal velocity structure between the northern (distances 0–120 km) and southern parts of the profile. The difference in P-wave velocities and Vp/Vs ratio can be followed through the whole crust down to the Moho boundary indicating major tectonic boundaries. Upper crustal velocities seem to vary with the terranes/compositional differences mapped at the surface. The lower layer of the upper crust displays velocities of 6.0–6.1 km/s. Both Paleoproterozoic and Archean terranes are associated with high velocity bodies (6.30–6.35 km/s) at 100 and 200–350 km distances. The Central Lapland greenstone belt and Central Lapland Granitoid complex are associated with a 4 km-thick zone of unusually low velocities (<6.0 km/s) at distances between 120 and 220 km. We interpret the HUKKA 2007 profile to image an old, partly buried, inverted continental rift zone that has been closed and modified by younger tectonic events. It has structural features typical of rifts: inward dipping rift shoulders, undulating thickness of the middle crust, high velocity lower crust and a rather uniform crustal thickness of 48 km.  相似文献   

Benthic time-series observations in North-eastern European Marine Station: Is a European label needed?     

Jean-Claude Dauvin 《Marine pollution bulletin》2010,60(4):483-488

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Human impact on Holocene sediment dynamics in the Eastern Mediterranean – the example of the Roman harbour of Ephesus          下载免费PDF全文

Friederike Stock  Maria Knipping  Anna Pint  Sabine Ladstätter  Hugo Delile  Andreas G. Heiss  Hannes Laermanns  Piers D. Mitchell  René Ployer  Martin Steskal  Ursula Thanheiser  Ralf Urz  Volker Wennrich  Helmut Brückner 《地球表面变化过程与地形》2016,41(7):980-996

During the past millennia, many erosion and accumulation processes have been modified by anthropogenic impact. This holds especially true for the environs of ancient settlements and their harbours along the Mediterranean coasts. Our multi‐proxy investigations in the Roman harbour and the harbour canal of Ephesus (western Turkey) reveals that humans have significantly triggered soil erosion during the last three millennia. Since the eighth century bc , and especially since the Hellenistic period, a high sedimentation rate indicates fast alluviation and delta progradation of the Küçük Menderes. Deforestation, agriculture (especially ploughing) and grazing (especially goats) were the main reasons for erosion of the river catchment area. One consequence was significant siltation of the Hellenistic/Roman harbour basin. This sediment trap archives the human impact, which was strongly enhanced from Hellenistic/Roman to Byzantine times (second/first centuries bc to the sixth/seventh centuries ad ), evidenced by high sedimentation rates, raised values of heavy metal contaminations [lead (Pb), copper (Cu)], the occurrence of fruit tree pollen and of intestinal parasites. From the middle to the end of the first millennium ad , the influence of Ephesus declined, which resulted in a decrease of human impact. Studies of several ancient settlements around the Mediterranean Sea tell a comparable story. They also confirm that during their most flourishing periods the human impact totally overprinted the climatic one. To detect the latter, geo‐bio‐archives of relatively pristine areas have to be investigated in detail. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Table of Contents     

Timo Vihma  Burghard Brümmer 《Boundary-Layer Meteorology》2002,105(3):507-508

Volume Contents

Table of Contents Volume 103  相似文献   

CCD BVI photometry and Coravel observations of stars in the open cluster NGC 2489     

Andrés E. Piatti  Juan J. Clariá  Jean-Claude Mermilliod  María C. Parisi  Andrea V. Ahumada 《Monthly notices of the Royal Astronomical Society》2007,377(4):1737-1746

We present CCD BVI photometry for the southern open cluster NGC 2489 and its surrounding field. The sample consists of 2182 stars measured in an area of 13.6 × 13.6 arcmin², extending down to   V ∼ 21.5  . These data are supplemented with CORAVEL radial-velocity observations for seven red giant candidates. A cluster angular radius of 6.7 ± 0.6 arcmin, equivalent to 3.5 ± 0.3 pc, is estimated from star counts carried out inside and outside the cluster region. The comparison of the cluster colour–magnitude diagrams with isochrones of the Padova group yields   E ( B − V ) = 0.30 ± 0.05, E ( V − I ) = 0.40 ± 0.05  and   V − M _V = 12.20 ± 0.25  for log   t = 8.70 ( t = 500⁺¹³⁰₋₁₀₀ Myr)  and   Z = 0.019  . NGC 2489 is then located at 1.8 ± 0.3 kpc from the Sun and 25 pc below the Galactic plane. The analysis of the kinematical data allowed us to confirm cluster membership for six red giants, one of them being a spectroscopic binary. A mean radial velocity of 38.13 ± 0.33 km s⁻¹ was derived for the cluster red giants. The properties of a sample of open clusters aligned along the line of sight of NGC 2489 are examined.  相似文献   

Phase changes and thermal subsidence in intracontinental sedimentary basins     

Yvette Hamdani  Jean-Claude Mareschal  Jafar Arkani-Hamed 《Geophysical Journal International》1991,106(3):657-665

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Transfrontier macroseismic observations of the Ml = 5.4 earthquake of February 22, 2003 at Rambervillers,France     

Michel?CaraEmail author  Wolfgang?Brüstle  Monika?Gisler  Philipp?K?stli  Christophe?Sira  Claire?Weihermüller  Jér?me?Lambert 《Journal of Seismology》2005,9(3):317-328

The 2003 Ml = 5.4 Rambervillers earthquake, north-east of France, is the largest seismic event recorded north of the Alps since the 1992 Ms = 5.3, I₀ = VII, Roermond earthquake, Netherlands. With a maximum macroseismic intensity of VI-VII EMS-98, the 2003 event was broadly felt to a distance of 300 km from the epicentre. It provides a unique opportunity to test and compare the different procedures used in France, Germany and Switzerland when evaluating macroseismic intensities. The main purpose of this paper is to present a common transfrontier macroseismic map based on the EMS-98 intensity scale. Maximum horizontal accelerations recorded in the area are compared to the intensity values, and we propose to use a differential technique to re-estimate the magnitude of the 1682 Remiremont, I₀ = VIII, earthquake, which occurred 40 km south of Rambervillers.  相似文献   

Reconstructing Northern Hemisphere upper-level fields during World War II     

S.?Br?nnimannEmail author  J.?Luterbacher 《Climate Dynamics》2004,22(5):499-510

Monthly mean fields of temperature and geopotential height (GPH) from 700 to 100 hPa were statistically reconstructed for the extratropical Northern Hemisphere for the World War II period. The reconstruction was based on several hundred predictor variables, comprising temperature series from meteorological stations and gridded sea level pressure data (1939-1947) as well as a large amount of historical upper-air data (1939-1944). Statistical models were fitted in a calibration period (1948-1994) using the NCEP/NCAR Reanalysis data set as predictand. The procedure consists of a weighting scheme, principal component analyses on both the predictor variables and the predictand fields and multiple regression models relating the two sets of principal component time series to each other. According to validation experiments, the reconstruction skill in the 1939-1944 period is excellent for GPH at all levels and good for temperature up to 500 hPa, but somewhat worse for 300 hPa temperature and clearly worse for 100 hPa temperature. Regionally, high predictive skill is found over the midlatitudes of Europe and North America, but a lower quality over Asia, the subtropics, and the Arctic. Moreover, the quality is considerably better in winter than in summer. In the 1945-1947 period, reconstructions are useful up to 300 hPa for GPH and, in winter, up to 500 hPa for temperature. The reconstructed fields are presented for selected months and analysed from a dynamical perspective. It is demonstrated that the reconstructions provide a useful tool for the analysis of large-scale circulation features as well as stratosphere-troposphere coupling in the late 1930s and early 1940s.Electronic Supplementary Material Suplementary material is available in the online version of this article at  相似文献