Geodynamics of the deep sedimentary basin of the Caspian Sea region: paragenetic correlation of seismicity and mud volcanism     

Ibrahim?Guliev  Behrouz?PanahiEmail author 《Geo-Marine Letters》2004,24(3):169-176

In this paper we analyze seismic regime and earthquake depth distribution and correlation of seismicity and mud volcanism in the Azerbaijan and the Caspian Sea region. For the present region we have calculated accurate source locations, seismic activity, earthquake repetition and released earthquake energy parameters. It is shown that the active tectonic processes in the region are concentrated within the thick sedimentary cover that we consider as a general source of contemporary stress and a main structural element responsible for the origin of regional earthquakes. The correlation of seismicity and mud volcanism is of paragenetic character.  相似文献   

Life history ofEuphausia similis (crustacea,euphausiacea) in Sagami Bay,central Japan     

Yuichi Hirota  Takahisa Nemoto  Ryuzo Marumo 《Journal of Oceanography》1990,46(6):237-249

The life history ofEuphausia similis G.O. Sars in Sagami Bay, central Japan, has been studied by examining the abundance, size distribution, and occurrence of each growing stage from egg to adult. Three cohorts were laid within the period from July 1979 to July 1980. Individuals of cohort I of 1980 were laid in November and December 1979, and matured and spawned in March and April of the following year. Those of cohort II of 1980 laid in January and February 1980 should mature in November and spawn after December, by analogy with cohort II of 1979. Cohort III of 1980 was laid in April 1980, but decreased in number in July. Cohort II was the dominant cohort in Sagami Bay throughout the period studied. From December 1979 to April 1980 when the mixing layer was present, many eggs ofE. similis were in the epipelagic zone. It is suggested that the spawning season ofE. similis roughly coincided with the season of active feeding, indicated by high fullness of stomachs in individuals. The production of juveniles and adults was about 1.33 mg C m^–2 day^–1, and the production to bio mass (P/B) ratio was estimated to be 4.78 between July 1979 and July 1980.  相似文献   

Bachelor-modon type eddies and isolated eddies near the coast on anf-plane     

Akira Masuda  Kenji Marubayashi  Michiyoshi Ishibashi 《Journal of Oceanography》1987,43(6):383-394

The behavior of isolated meso-scale eddies near the coastal boundary is studied by numerical experiments based on the quasi-geostrophic equation in a basin on an f-plane. First, Bachelor-modon type eddies are investigated as an idealized model of isolated eddies close to the wall. The first-mode Bachelor-modon type eddy is found to be robust enough to recover its original form even after it turns a corner of the basin. In contrast, the second mode is unstable; it tends to move away from the wall and finally splits into two eddies proceeding in opposite directions along the wall. An initially Gaussian eddy a little distant from the boundary interacts with a Bachelor-modon type eddy translating along the boundary, sometimes resulting in vortex merging and pairing just as in the head-on collision of two modons on a beta-plane. It is found that an initially Gaussian eddy located moderately close to the coast rapidly settles down to a steadily translating eddy, which can be approximated remarkably well by a first-mode Bachelor-modon type eddy not only in appearance but also in translation velocity within an error of about 20%.  相似文献   

Estimating the geostrophic velocity obtained by HF radar observations in the upstream area of the Kuroshio     

Ryoko Tokeshi  Kaoru Ichikawa  Satoshi Fujii  Kenji Sato  Shoichiro Kojima 《Journal of Oceanography》2007,63(4):711-720

A method to extract geostrophic current in the daily mean HF radar data in the Kuroshio upstream region is established by comparison with geostrophic velocity determined from the along-track altimetry data. The estimated Ekman current in the HF velocity is 1.2% (1.5%) and 48° (38°)-clockwise rotated with respect to the daily mean wind in (outside) the Kuroshio. Furthermore, additional temporal smoothing is found necessary to remove residual ageostrophic currents such as the inertial oscillation. After removal of the ageostrophic components, the HF geostrophic velocity agrees well with that from the altimetry data with rms difference 0.14 (0.12) m/s in (outside) the Kuroshio.  相似文献   

Oil-generation kinetics for organic facies with Type-II and -IIS kerogen in the Menilite Shales of the Polish Carpathians     

M.D. Lewan  M.J. Kotarba  D. Wi?c?aw 《Geochimica et cosmochimica acta》2006,70(13):3351-3368

The Menilite Shales (Oligocene) of the Polish Carpathians are the source of low-sulfur oils in the thrust belt and some high-sulfur oils in the Carpathian Foredeep. These oil occurrences indicate that the high-sulfur oils in the Foredeep were generated and expelled before major thrusting and the low-sulfur oils in the thrust belt were generated and expelled during or after major thrusting. Two distinct organic facies have been observed in the Menilite Shales. One organic facies has a high clastic sediment input and contains Type-II kerogen. The other organic facies has a lower clastic sediment input and contains Type-IIS kerogen. Representative samples of both organic facies were used to determine kinetic parameters for immiscible oil generation by isothermal hydrous pyrolysis and S₂ generation by non-isothermal open-system pyrolysis. The derived kinetic parameters showed that timing of S₂ generation was not as different between the Type-IIS and -II kerogen based on open-system pyrolysis as compared with immiscible oil generation based on hydrous pyrolysis. Applying these kinetic parameters to a burial history in the Skole unit showed that some expelled oil would have been generated from the organic facies with Type-IIS kerogen before major thrusting with the hydrous-pyrolysis kinetic parameters but not with the open-system pyrolysis kinetic parameters. The inability of open-system pyrolysis to determine earlier petroleum generation from Type-IIS kerogen is attributed to the large polar-rich bitumen component in S₂ generation, rapid loss of sulfur free-radical initiators in the open system, and diminished radical selectivity and rate constant differences at higher temperatures. Hydrous-pyrolysis kinetic parameters are determined in the presence of water at lower temperatures in a closed system, which allows differentiation of bitumen and oil generation, interaction of free-radical initiators, greater radical selectivity, and more distinguishable rate constants as would occur during natural maturation. Kinetic parameters derived from hydrous pyrolysis show good correlations with one another (compensation effect) and kerogen organic-sulfur contents. These correlations allow for indirect determination of hydrous-pyrolysis kinetic parameters on the basis of the organic-sulfur mole fraction of an immature Type-II or -IIS kerogen.  相似文献   

T -distributed Random Fields: A Parametric Model for Heavy-tailedWell-log Data1     

Jo R?islien  Henning Omre 《Mathematical Geology》2006,38(7):821-849

Histograms of observations from spatial phenomena are often found to be more heavy-tailed than Gaussian distributions, which makes the Gaussian random field model unsuited. A T-distributed random field model with heavy-tailed marginal probability density functions is defined. The model is a generalization of the familiar Student-T distribution, and it may be given a Bayesian interpretation. The increased variability appears cross-realizations, contrary to in-realizations, since all realizations are Gaussian-like with varying variance between realizations. The T-distributed random field model is analytically tractable and the conditional model is developed, which provides algorithms for conditional simulation and prediction, so-called T-kriging. The model compares favourably with most previously defined random field models. The Gaussian random field model appears as a special, limiting case of the T-distributed random field model. The model is particularly useful whenever multiple, sparsely sampled realizations of the random field are available, and is clearly favourable to the Gaussian model in this case. The properties of the T-distributed random field model is demonstrated on well log observations from the Gullfaks field in the North Sea. The predictions correspond to traditional kriging predictions, while the associated prediction variances are more representative, as they are layer specific and include uncertainty caused by using variance estimates.  相似文献   

Late Early Miocene lake deposits near Mauensee, central Switzerland: Fish fauna (otoliths, teeth), accompanying biota and palaeoecology     

Jürg Jost  Daniel K?lin  Tanja Schulz-Mirbach  Bettina Reichenbacher 《Eclogae Geologicae Helvetiae》2006,99(3):309-326

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韧性剪切变形对岩石地球化学行为的制约——以北阿尔金巴什考供韧性剪切带为例   总被引：6，自引：0，他引：6  

戚学祥李海兵  吴才来陈松永 《地质通报》2005,24(3):252-257

韧性剪切变形对岩石地球化学行为的制约一直是地质学家们探讨的课题。本文以构成北阿尔金红柳沟——拉配泉俯冲碰撞杂岩带与北阿尔金地块边界的巴什考供斜向逆冲型韧性剪切带为例，通过对韧性剪切带内花岗岩变形前后不同变形强度构造岩的地球化学组成进行对比，确定等比线斜率，探讨韧性变形对岩石体积和成分变异的影响。计算结果表明，在糜棱岩化过程中，糜棱岩化花岗岩体积亏损21％，花岗质糜棱岩体积亏损31％。质量平衡计算结果和等比线图表明，韧；陛剪切作用导致SiO2，流失量最大，A12O3、K2O及Ba、Rb、Sr等都有不同程度的丢失，显示出较强的活动性，MnO、P2O5、Sc位于等比线上或附近，表现出相对的稳定性。岩石中活动组分的变异是流体渗滤作用引起的，不活动组分的变异是体．积亏损造成的。  相似文献   

应用等效纬度-海拔模型进行地温及多年冻土制图   总被引：2，自引：2，他引：2  

KenjiYoshikawa PrasadGogineni 《冰川冻土》2002,24(5):526-531

This research presents a method for permafrost mapping in discontinuous permafrost regions based on equivalent latitude/elevation concept in interior Alaska. In winter months, study site has a strong temperature inversion in air up to 700 m elevation. Air temperature data and the effects of slope, aspect and elevation were used to create an equivalent latitude/elevation model. This model was well correlated with mean annual surface temperature (0.79). In this watershed, the thawing index (It≈1 400 ℃*days) at the ground surface and snow depth do not vary greatly from south facing to north facing slopes. The primary controlled factor that determines the mean annual surface temperature was the winter surface temperature. The permafrost stability is effectively controlled by the freezing index. We determined 37.5% of Caribou-Poker Creeks Research Watershed has unstable or thawing permafrost. At least 2.1% of the permafrost in this watershed may have disappeared in the last 90 years due to climate warming. This method makes it possible to evaluate the permafrost stability in the present, past and future.  相似文献   

新时期我国区域经济地理学发展问题初探   总被引：4，自引：0，他引：4  

刘曙光 《地域研究与开发》2002,21(2):1-4

我国新时期的区域经济地理学在取得全面发展的同时，在理论体系，研究方法和实践领域等方面还需要进一步的发展，文章根据学习和实践区域经济地理学的体会，初步提出基础理论和应用理论，思维方法和技术方法等方面发展见解，并指出区域创新系统和国际经济技术合作等学科应注意拓展的重要实践领域，最后提出我国区域经济地理学科发展的建议。  相似文献