辽北西丰地区宝兴岩体LA-ICP-MS锆石U-Pb年龄及岩石地球化学特征     

彭游博  宋淑娥  刘锦  张文静  王恩德  赵辰 《地质通报》2017,36(10):1698-1707

宝兴岩体位于华北板块北缘陆缘活动带东段,岩性为花岗闪长岩,LA-ICP-MS锆石~(206)Pb/~(238)U年龄加权平均值为235.0±1.3Ma,属于中三叠世。岩石的K_2O/Na_2O平均值为1.07,属高钾钙碱性系列;富集大离子亲石元素,亏损高场强元素,具有活动陆缘钙碱性岩系特征;稀土元素总量平均值为147×10~(-6),稀土元素配分曲线右倾,属具中等负Eu异常的轻稀土元素富集、重稀土元素亏损型。通过岩石学、岩石地球化学及年代学研究,结合邻区构造演化研究,认为中三叠世研究区在伸展作用下岩石圈进行拆沉,从而形成大规模的岩浆活动。  相似文献   

辽宁清河断裂以北新太古代变质表壳岩的发现及其地质意义   总被引：1，自引：0，他引：1  

刘锦  刘正宏  赵辰  彭游博  王楚杰  杨仲杰  豆世勇 《吉林大学学报(地球科学版)》2017,47(2)

通过详实的地质填图,在辽宁开原地区清河断裂以北新发现一套变质表壳岩组合,主要岩性为斜长角闪岩、黑云角闪斜长变粒岩、黑云角闪斜长片麻岩、浅粒岩及角闪石岩的岩石组合,与红透山岩组基本可以对比。岩石地球化学特征表明,其原岩主要为一套中、中基性的火山岩建造,形成于岛弧环境。该套岩石组合普遍发生强烈的构造变形作用,常见构造样式包括透入性片麻理、石香肠构造、变质分异条带、肠状褶皱等一系列的固态流变构造。对该套变质表壳岩组合中的斜长角闪岩进行LA-ICP-MS锆石U-Pb测年,结果表明其形成于(2 524±18)Ma,变质年龄为(2 477±21)Ma,从形成到发生变质相隔约为47Ma。该套变质表壳岩组合的发现,表明了清河断裂以北也曾存在太古宙结晶基底,清河断裂与寇河断裂之间的区域在构造环境上与清原地区一样,均属于新太古代绿岩带。  相似文献   

二元同位素测温技术及其在白云岩储层成因研究中的应用——以塔里木盆地中下寒武统为例     

郑剑锋  李晋  季汉成  黄理力  胡安平  马明璇 《海相油气地质》2017,22(2)

作为近年来新兴的实验技术,二元同位素(D47)测温技术已被应用于碳酸盐岩成岩环境的研究中。简要介绍了二元同位素测温技术的原理及应用方法,并以塔里木盆地中下寒武统白云岩为例,优选11块样品,测试其D47值和白云石的碳氧同位素,并计算出样品的成岩温度和古流体的δ~(18)O值。综合分析认为:样品中,颗粒白云岩形成于低温准同生—浅埋藏环境,成岩流体为海水;细晶白云岩为深埋藏成岩环境中原岩受到了高温重结晶作用的改造,成岩流体为地下热卤水;孔缝中的白云石胶结物是深埋藏成岩环境富镁热卤水沉淀作用的产物。研究证明二元同位素测温技术可以较好地恢复白云岩的成岩温度,减少储层成因的多解性,它为今后储层成因研究提供了一种新的手段和依据。  相似文献   

A modified normalized model for predicting effective soil thermal conductivity     

Hailong He  Ying Zhao  Miles F. Dyck  Bingcheng Si  Huijun Jin  Jialong Lv  Jinxin Wang 《Acta Geotechnica》2017,12(6):1281-1300

Effective soil thermal conductivity (λ _eff) describes the ability of a multiphase soil to transmit heat by conduction under unit temperature gradient. It is a critical parameter for environmental science, earth and planetary science, and engineering applications. Numerous models are available in the literature, but their applicability is generally restricted to certain soil types or water contents (θ). The objective of this study was to develop a new model in the similar form of the Johansen 1975 model to simulate the λ _eff(θ) relationship of soils of various soil textures and water contents. An exponential type model with two parameters is developed and a new function for calculating dry soil thermal conductivity is presented. Performance of the new model and six other normalized models were evaluated with published datasets. The results show that the new model is able to well mimic λ _eff(θ) relationship of soils from sand to silt loam and from oven dry to full saturation. In addition, it has the best performance among the seven models under test (with root-mean-square error of 0.059 W m^?1 °C^?1, average deviations of 0.0009 W m^?1 °C^?1, and Nash–Sutcliffe efficiency of 0.994). The new model has potential to improve the reliability of soil thermal conductivity estimation and be incorporated into numerical modeling for environmental, earth and engineering studies.  相似文献   

Estimation of critical state-related formula in advanced constitutive modeling of granular material   总被引：1，自引：0，他引：1  

Yin-Fu Jin  Ze-Xiang Wu  Zhen-Yu Yin  Jack Shuilong Shen 《Acta Geotechnica》2017,12(6):1329-1351

Different critical state-related formulas, for the critical state line and the critical state-dependent interlocking effect, have been proposed in constitutive modeling of granular material during last decades, which rises up a confusion on how to select an appropriate model in the geotechnical applications. This paper aims to discuss the selection of these critical state-related formulas and parameters identification. Three formulas of critical state line together with two formulas of critical state-dependent interlocking effect are combined to propose six elasto-plastic models. Drained and undrained triaxial tests on four different granular materials are selected for simulations. In order to eliminate artificial errors, a new hybrid genetic algorithm-based intelligent method is proposed and used to identify parameters and estimate simulations with minimum errors for each granular material and each model. Then, the performance of each CSL and each state parameter is evaluated using two information criteria. Furthermore, the performance was evaluated by simulating three footing tests using finite-element analysis in which the models are implemented. All comparisons demonstrate the incorporation of nonlinear critical state line combined with the state parameter e/e _c in constitutive modeling can result in relatively more satisfied simulated results.  相似文献   

An efficient optimization method for identifying parameters of soft structured clay by an enhanced genetic algorithm and elastic–viscoplastic model     

Zhen-Yu Yin  Yin-Fu Jin  Shui-Long Shen  Hong-Wei Huang 《Acta Geotechnica》2017,12(4):849-867

Soft structured clays usually exhibit complex behaviors, which can lead to difficulties in the determination of parameters and high testing costs. This paper aims to propose an efficient optimization method for identifying the parameters of advanced constitutive model for soft structured clays from only limited conventional triaxial tests. First, a new real-coded genetic algorithm (RCGA) is proposed by combining two new crossover and mutation operators for improving the performance of optimization. A newly developed elastic–viscoplastic model accounting for anisotropy, destructuration and creep features is enhanced with the cross-anisotropy of elasticity and is adopted for test simulations during optimization. Laboratory tests on soft Wenzhou marine clay are selected, with three of them being used as objectives for optimization and others for validation. The optimization process, using the new RCGA with a uniform sampling initialization method, is carried out to obtain the soil parameters. A classic genetic algorithm (NSGA-II)-based optimization is also conducted and compared to the RCGA for estimating the performance of the new RCGA. Finally, the optimal parameters are validated by comparing with other measurements and test simulations on the same clay. All comparisons demonstrate that a reliable solution can be obtained by the new RCGA optimization combined with the appropriate soil model, which is practically useful with a reduction in testing costs.  相似文献   

Hydrothermal plume mapping as a prospecting tool for seafloor sulfide deposits: a case study at the Zouyu-1 and Zouyu-2 hydrothermal fields in the southern Mid-Atlantic Ridge   总被引：2，自引：0，他引：2  

Chunhui Tao  Sheng Chen  Edward T. Baker  Huaiming Li  Jin Liang  Shili Liao  Yongshun John Chen  Xianming Deng  Guoyin Zhang  Chunhua Gu  Jialin Wu 《Marine Geophysical Researches》2017,38(1-2):3-16

Seafloor hydrothermal polymetallic sulfide deposits are a new type of resource, with great potential economic value and good prospect development. This paper discusses turbidity, oxidation–reduction potential, and temperature anomalies of hydrothermal plumes from the Zouyu-1 and Zouyu-2 hydrothermal fields on the southern Mid-Atlantic Ridge. We use the known location of these vent fields and plume data collected in multiple years (2009, 2011, 2013) to demonstrate how real-time plume exploration can be used to locate active vent fields, and thus associated sulfide deposits. Turbidity anomalies can be detected 10 s of km from an active source, but the location precision is no better than a few kilometers because fine-grained particles are quasi-conservative over periods of many days. Temperature and oxidation–reduction potential anomalies provide location precision of a few hundred meters. Temperature anomalies are generally weak and difficult to reliably detect, except by chance encounters of a buoyant plume. Oxidation–reduction potential is highly sensitive (nmol concentrations of reduced hydrothermal chemicals) to discharges of all temperatures and responds immediately to a plume encounter. Real-time surveys using continuous tows of turbidity and oxidation–reduction potential sensors offer the most efficient and precise surface ship exploration presently possible.  相似文献   

<Superscript>230</Superscript>Th/<Superscript>238</Superscript>U dating of hydrothermal sulfides from Duanqiao hydrothermal field,Southwest Indian Ridge     

Weifang Yang  Chunhui Tao  Huaiming Li  Jin Liang  Shili Liao  Jiangping Long  Zhibang Ma  Lisheng Wang 《Marine Geophysical Researches》2017,38(1-2):71-83

Duanqiao hydrothermal field is located between the Indomed and Gallieni fracture zones at the central volcano, at 50°28′E in the ultraslow-spreading Southwest Indian Ridge (SWIR). Twenty-eight subsamples from a relict chimney and massive sulfides were dated using the ²³⁰Th/²³⁸U method. Four main episodes of hydrothermal activity were determined according to the restricted results: 68.9–84.3, 43.9–48.4, 25.3–34.8, and 0.7–17.3 kyrs. Hydrothermal activity of Duanqiao probably started about 84.3 (±0.5) kyrs ago and ceased about 0.737 (±0.023) kyrs ago. The periodic character of hydrothermal activity may be related to the heat source provided by the interaction of local magmatism and tectonism. The estimated mean growth rate of the sulfide chimney is <0.02 mm/yr. This study is the first to estimate the growth rate of chimneys in the SWIR. The maximum age of the relict chimney in Duanqiao hydrothermal filed is close to that of the chimneys from Mt. Jourdanne (70 kyrs). The hydrothermal activity in Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. The massive sulfides are younger than the sulfides from other hydrothermal fields such as Rainbow, Sonne and Ashadze-2. The preliminarily estimated reserves of sulfide ores of Duanqiao are approximately 0.5–2.9 million tons.  相似文献   

关于澜沧江正源问题   总被引：8，自引：2，他引：8  

靳长兴  周长进 《地理研究》1995,14(1):44-49

通过对澜沧江源头地区的水文、气候、地貌及河流特征等实地考察后确认,澜沧江正源应为扎阿曲,发源于青海省玉树藏族自治州杂多县阿青乡拉赛贡玛山南面的冰川末端。  相似文献   

资源三号卫星在区域地质灾害应急监测中的应用——以山西省为例     

于颂  陈峰  张锦 《测绘通报》2016,(4):68-71

遥感技术已成为当前应对突发地质灾害应急监测的一种重要技术手段。本文将资源三号卫星遥感影像应用于区域地质灾害应急监测中,研究了资源三号卫星区域RPC参数的修正方法,并联合DEM和控制点建立了区域影像快速正射纠正的方法流程;利用长治地区的资源三号卫星影像进行了正射纠正试验与分析,总体满足区域地质灾害应急监测对遥感影像的精度要求。利用该方法制作完成的地质灾害区域遥感影像已应用于山西省突发地质灾害遥感监测指挥系统项目中并取得了较好的应用效果。  相似文献