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Reza Deevsalar Ryuichi Shinjo Jean P. Liégeois Mohammad V. Valizadeh Jamshid Ahmadian Hadi Yeganehfar Mamoru Murata Iain Neill 《Swiss Journal of Geoscience》2018,111(1-2):269-293
The Malayer–Boroujerd plutonic complex (MBPC) in western Iran, consists of a portion of a magmatic arc built by the northeast verging subduction of the Neo-Tethys plate beneath the Central Iranian Microcontinent (CIMC). Middle Jurassic-aged felsic magmatic activity in MBPC is manifested by I-type and S-type granites. The mafic rocks include gabbroic intrusions and dykes and intermediate rocks are dioritic dykes and minor intrusions, as well as mafic microgranular enclaves (MMEs). MBPC Jurassic-aged rocks exhibit arc-like geochemical signatures, as they are LILE- and LREE-enriched and HFSE- and HREE-depleted and display negative Nb–Ta anomalies. The gabbro dykes and intrusions originated from metasomatically enriched garnet-spinel lherzolite [Degree of melting (fmel) ~ 15%] and exhibit negative Nd and positive to slightly negative εHf(T) (+ 3.0 to ? 1.6). The data reveal that evolution of Middle Jurassic magmatism occurred in two stages: (1) deep mantle-crust interplay zone and (2) the shallow level upper crustal magma chamber. The geochemical and isotopic data, as well as trace element modeling, indicate the parent magma for the MBPC S-type granites are products of upper crustal greywacke (fmel: 0.2), while I-type granites formed by partial melting of amphibolitic lower crust (fmel: 0.25) and mixing with upper crustal greywacke melt in a shallow level magma chamber [Degree of mixing (fmix): 0.3]. Mixing between andesitic melt leaving behind a refractory dense cumulates during partial crystallization of mantle-derived magma and lower crustal partial melt most likely produced MMEs (fmix: 0.2). However, enriched and moderately variable εNd(T) (? 3.21 to ? 4.33) and high (87Sr/86Sr)i (0.7085–0.7092) in dioritic intrusions indicate that these magmas are likely experienced assimilation of upper crustal materials. The interpretations of magmatic activity in the MBPC is consistent with the role considered for mantle-derived magma as heat and mass supplier for initiation and evolution of magmatism in continental arc setting, elsewhere. 相似文献
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采用西藏测震台网记录的2008年1月—2018年12月谢通门区域定位地震,系统分析该区M_L1.5以上地震频度变化及与附近强震的对应关系,发现地震台站建设密度对谢通门地震窗监控能力影响较大,故从2008—2011年和2012年7月—2018年12月2个时段予以分析。分析发现,2012年7月开始,谢通门地震窗小震活动水平在每月20次范围内随机波动,当超过20次以上(含20次)即异常高值出现或结束后1.5年内,在半径100 km以内具有发生M_S 5.0以上地震的可能,在半径1 000 km以内具有发生M_S 6.5以上强震的可能。 相似文献
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Strength behavior and microstructural characteristics of tropical laterite soil treated with sodium silicate-based liquid stabilizer 总被引：4，自引：1，他引：3
Although the effects of nontraditional stabilizers on the geotechnical properties of tropical soils has been the issue of investigation in recent years, the micro-structural characteristics of nontraditional soil additives and in particular selected additive (TX-85) have not been fully studied. Nontraditional soil stabilization additives are widely used for stabilizing marginal materials. These additives are low-cost alternatives to traditional construction materials and have different compositions. They also differ from one another while interacting with soil. In line with that, it was the objective of this research to investigate the strength properties and physicochemical mechanisms related to tropical laterite soil mixed with the liquid stabilizer TX-85. Macro-structure study, i.e., compaction, and unconfined compression strength test were used to assess the engineering and shear properties of the stabilized laterite soil. In addition, the possible mechanisms that contributed to the stabilization process were discussed using various spectroscopic and microscopic techniques such as X-ray diffractometry (XRD), energy-dispersive X-ray spectrometry, scanning electron microscopy, and Fourier transform infrared spectroscopy. From engineering point of view, the results indicated that the strength of TX-85 stabilized laterite soil improved significantly. The degree of improvement was approximately four times stronger than natural soil after a 7-day curing period. The XRD showed no crystalline products (gel form). Moreover, weathering effects were obvious in TX-85 treated samples in most of clay minerals’ peak intensities. These effects were reduced especially for kaolinite mineral inside the soil with curing time. 相似文献
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A Hierarchical Bayesian Model Averaging Framework for Groundwater Prediction under Uncertainty 
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下载免费PDF全文 Groundwater prediction models are subjected to various sources of uncertainty. This study introduces a hierarchical Bayesian model averaging (HBMA) method to segregate and prioritize sources of uncertainty in a hierarchical structure and conduct BMA for concentration prediction. A BMA tree of models is developed to understand the impact of individual sources of uncertainty and uncertainty propagation to model predictions. HBMA evaluates the relative importance of different modeling propositions at each level in the BMA tree of model weights. The HBMA method is applied to chloride concentration prediction for the “1,500‐foot” sand of the Baton Rouge area, Louisiana from 2005 to 2029. The groundwater head data from 1990 to 2004 is used for model calibration. Four sources of uncertainty are considered and resulted in 180 flow and transport models for concentration prediction. The results show that prediction variances of concentration from uncertain model elements are much higher than the prediction variance from uncertain model parameters. The HBMA method is able to quantify the contributions of individual sources of uncertainty to the total uncertainty. 相似文献
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ZhongPing Lee Mingshun Jiang Curtiss Davis Nima Pahlevan Yu-Hwan Ahn Ronghua Ma 《Ocean Science Journal》2012,47(3):323-329
Ocean-color imagers on conventional polar-orbiting satellites have a revisit time of ??2 days for most regions, which is further reduced if the area is frequently cloudy. The Geostationary Ocean Color Imager (GOCI), the first ocean-color imager on a geostationary satellite, provides measurements 8 times a day, thus significantly improving the frequency of measurements for studies of ocean environments. Here, we use results derived from GOCI measurements over Taihu Lake to demonstrate that the extra sampling can be used to improve the accuracy of statistically averaged longer-term (daily) measurements. Additionally, using numerical simulations, we demonstrate that the coupling of diurnal variations of both biomass and photosynthetic available radiation can improve the accuracy of daily primary production estimates. These results echo that higher sampling frequency can improve our estimates of longer-term dynamics of biogeochemical processes and highlights the value of ocean color measurements from geostationary satellites. 相似文献
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Nima Rahgozar Abdolreza S. Moghadam Armin Aziminejad 《Bulletin of Earthquake Engineering》2018,16(9):4081-4106
Unlike conventional seismic resisting systems, rocking core-moment frame (RCMF) combinations as low-damage assemblies are being developed to mitigate, or even eliminate structural damage and residual deformations following a severe earthquake. Despite extensive studies on the performance of specific rocking cores, dynamic characteristics and strength demands of a generic RCMF have not been addressed. By utilizing cantilever beam analogy, the current article proposes a modal analysis method to formulate RCMF demands. The proposed model and obtained analytical charts provide a manual method for rapid study and preliminary design of low- to mid-rise RCMFs with relatively uniform properties over the height. An extensive parametric study investigates the effects of rocking core base-fixity and frame-to-core stiffness on demand values. An independent computer analysis verifies the validity and accuracy of the proposed formulas. Findings show significant higher-mode effects in several RCMF combinations. 相似文献
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The charging of solid grains in a plasma environment is considered in this study. It is found that grains with zero initial potential gradually gain a negative potential and approach equilibrium. This potential depends most strongly on the plasma temperature. If secondary and photoemission of electrons from this grain is not considered, this equilibrium potential is about –2.7 times the plasma thermal energy. If secondary and photoemission is included, the grain can approach equilibrium at positive rather than negative potential. In this case the sign and the value of the equilibrium potential depends strongly on the material properties and to lesser extent on plasma temperature. This implies that grains of different composition can have different, possibly even opposite, equilibrium potentials in the same plasma environment. 相似文献
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色日绒地区冰海杂砾岩产于砂泥质为主的陆缘碎屑岩段中,累计出露厚度约325 m。岩石学及沉积学特征指示其沉积于滨海—上部浅海环境;顶部的化石生物组合指示此段岩层沉积于晚石炭世—早二叠世的冷水型海洋环境。岩层中的坠石结构、压裂面以及与其同层位产出的冷水型生物群为冰海杂砾岩的成因提供了有力的证据,指示其形成于冰川作用下,是由冰筏搬运的海相沉积。通过资料综合收集、对比,确定了冰海杂砾岩形成的古构造及古地理、古气候控制条件。根据古构造位置及古地理特征,大致总结出了以该地区为代表的冈瓦纳相冰海杂砾岩的沉积及成因模式。 相似文献
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