基于HYCOM再分析数据研究琉球海流的形成与起源     

汪敏  刘昭君  朱小华  闫晓梅  张钟哲  赵瑞祥 《海洋学报(英文版)》2019,38(11):1-10

The origin of the Ryukyu Current(RC) and the formation of its subsurface velocity core were investigated using a 23-year(1993–2015) global Hybrid Coordinate Ocean Model(HYCOM) dataset. The volume transport of the RC comes from the Kuroshio eastward branch(KEB) east of Taiwan and part of the North Pacific Subtropical Gyre(pNPSG). From the surface to 2 000 m depth, the KEB(p-NPSG) transport contributes 41.5%(58.5%) to the mean total RC transport. The KEB originally forms the subsurface velocity core of the RC east of Taiwan due to blockage of the subsurface Kuroshio by the Ilan Ridge(sill depth: 700 m). Above 700 m, the Kuroshio can enter the East China Sea(ECS) over the Ilan Ridge, meanwhile, the blocked Kuroshio below 700 m turns to the right and flows along the Ryukyu Islands. With the RC flowing northeastward, the p-NPSG contribution strengthens the subsurface maximum structure of the RC owing to the blockage of the Ryukyu Ridge. In the surface layer, the pNPSG cannot form a stable northeastward current due to frequent disturbance by mesoscale eddies and water exchange through the gaps(with net volume transport into ECS) between the Ryukyu Islands.  相似文献   

Integrating isolated and riparian wetland modules in the PHYSITEL/HYDROTEL modelling platform: model performance and diagnosis          下载免费PDF全文

Maxime Fossey  Alain N. Rousseau  Fatima Bensalma  Stéphane Savary  Alain Royer 《水文研究》2015,29(22):4683-4702

Mathematical modelling is a well‐accepted framework to evaluate the effects of wetlands on stream flow and watershed hydrology in general. Although the integration of wetland modules into a distributed hydrological model represents a cost‐effective way to make this assessment, the added value brought by landscape‐specific modules to a model's ability to replicate basic hydrograph characteristics remains unclear. The objectives of this paper were the following: (i) to present the adaptation of PHYSITEL (a geographic information system) to parameterize isolated and riparian wetlands; (ii) to describe the integration of specific isolated wetland and riparian wetland modules into HYDROTEL, a distributed hydrological model; and (iii) to evaluate the performance of the updated modelling platform with respect to the capacity of replicating various hydrograph characteristics. To achieve this, two sets of simulations were performed (with and without wetland modules), and the added value was assessed at three river segments of the Becancour River watershed, Quebec, Canada, using six general goodness‐of‐fit indicators and 14 water flow criteria. A sensitivity analysis of the wetland module parameters was performed to characterize their impact on stream flows of the modelled watershed. Results of this study indicate the following: (i) integration of specific wetland modules can slightly increase the capacity of HYDROTEL to replicate basic hydrograph characteristics; and (ii) the updated modelling platform allows for the explicit assessment of the impact of wetlands (e.g. typology and location) on watershed hydrology. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

U–Pb and Re–Os geochronology and geodynamic setting of the Dabaoshan polymetallic deposit, northern Guangdong Province, South China     

Lei Wang  Mingan Hu  Zhen Yang  Wenjun Qu  Jinlong Xia  Kaixu Chen 《Ore Geology Reviews》2011,43(1):40-49

The Dabaoshan polymetallic deposit in northern Guangdong Province contains iron, copper, lead, zinc, molybdenum, tungsten and sulfur mineral resources. Porphyry-type Mo(W) and skarn-type Mo-W mineralization occurs along the internal and external contact zones of the granodioritic porphyry, respectively. LA-ICP-MS U–Pb dating of zircons from two granodioritic porphyry samples yielded a weighted mean ²⁰⁶Pb/²³⁸U age of 175.8 ± 1.5 Ma (MSWD = 0.037) and 175.0 ± 1.7 Ma (MSWD = 0.41). They can be pooled together to yield a combined weighted age of 175.4 ± 1.6 Ma (MSWD = 0.26), which is interpreted as the emplacement age of the granodioritic porphyry. Re–Os dating of three molybdenite samples from porphyry and skarn ores yielded consistent model ages of 163.2 ± 2.3 Ma to 165.2 ± 2.4 Ma, with a weighted mean of 163.9 ± 1.3 Ma (MSWD = 0.81), which is the age of Mo–W mineralization. These ages are consistent with the molybdenite Re–Os model age (164.7 ± 3 Ma) measured by Mao et al. (2004a) for the stratiform Cu–Pb–Zn orebody, and they can yield a weighted mean of 164.0 ± 2.5 Ma (MSWD = 0.16). This implies that Mo–W and Cu–Pb–Zn mineralization in the Dabaoshan polymetallic deposit are the products of one mineralization event. The mineralization in the deposit coincides closely with that of Mo-polymetallic mineralization (164–149 Ma) elsewhere in the Nanling region, comprising an important polymetallic metallogenic belt of south China, and corresponds to the second episode of Mesozoic metallogenesis in South China. Combined with previous studies, we suggest that the Dabaoshan polymetallic deposit is related to post-collisional lithosphere extension in the Nanling region of South China. Geological data and Pb isotopic evolution diagrams, together with stable isotopic data of fluid inclusions (δ¹⁸O = − 3.75–7.0‰, δD = − 50.7 to − 56.1‰) and ore sulfides (δ³⁴S = − 2–3‰), suggest a genetic relationship between the Dabaoshan polymetallic deposit, the granodioritic porphyry and the dacitic porphyry. These data, combined with the Re content (64.7 to 102.4 ppm) of molybdenite, indicate that the ore-forming components were derived from mixed crustal and mantle sources.  相似文献   

内蒙古乌拉特中旗北七哥陶辉长岩SHRIMP锆石 U-Pb年龄、地球化学特征及其地质意义   总被引：12，自引：3，他引：9  

赵磊  吴泰然  罗红玲 《岩石学报》2011,27(10):3071-3082

内蒙古乌拉特中旗温更地区北七哥陶辉长岩岩体由橄榄辉长岩和角闪辉长岩组成,主要造岩矿物为橄榄石、辉石、斜长石及角闪石等.锆石SHRIMP U-Pb同位素定年结果表明,橄榄辉长岩形成于269±8Ma,为晚古生代华北板块北缘岩浆活动的产物.橄榄辉长岩和角闪辉长岩具有相似的稀土元素、微量元素以及同位素特征,即:轻稀土元素( LREE)富集的右倾平滑配分模式;大离子亲石元素(LILE)K、Sr、Ba明显富集,高场强元素(HFSE) Nb、Ta、U、Th相对亏损,但Zr-Hf不亏损;87Sr/86Sr(t)平均值分别为0.706776和0.706960,εNd(t)平均值分别为-8.8和-8.9,206pb/204Pb、207pb/204Pb、208Pb/204Pb比值的平均值分别为17.2019和17.2277、15.4252和15.4524、37.3082和37.4724,在s7 Sr/86Sr(t)-143Nd/144 Nd (t)图解上,北七哥陶辉长岩都落在了EMI型富集地幔附近.根据以上事实,结合区域资料表明,橄榄辉长岩和角闪辉长岩产于后碰撞的构造环境,并且来自相同的岩浆源区,主要继承了华北陆块内部EMI型富集地幔,可能受到了古亚洲洋俯冲消减过程中再循环下地壳组分对岩石圈地幔的改造.  相似文献   

基于多层递阶和回归分析的单一水位流量关系曲线高水延长方法     

程银才  范世香 《水文》2011,(4):55-57

测站的水位流量关系由于受到多种因素的影响,没有固定的曲线线型,使得水位流量关系曲线的延长变得较为困难。多层递阶方法将预测系统视为动态系统,具有跟踪系统时变参数的特性,但没能考虑高相关影响因子的重要性。回归分析考虑到了高相关影响因子的重要性,但由于采用定常参数建模,不能反映动态系统时变参数的特性。将多层递阶方法和回归分析方法结合起来,用于单一水位流量关系曲线的高水延长。方法克服了传统的单一水位流量关系曲线高水延长时线型的需要选择、精度难以控制、效率低和不易程序化等缺点,为单一水位流量关系曲线的高水延长提供了一种新途径。  相似文献   

Changes of Late Mesozoic Tectonic Regimes around the Ordos Basin (North China) and their Geodynamic Implications   总被引：4，自引：0，他引：4  

ZHANG Yueqiao  SHI Wei  DONG Shuwen 《《地质学报》英文版》2011,85(6):1254-1276

A synthesis is given in this paper on late Mesozoic deformation pattern in the zones around the Ordos Basin based on lithostratigraphic and structural analyses. A relative chronology of the late Mesozoic tectonic stress evolution was established from the field analyses of fault kinematics and constrained by stratigraphic contact relationships. The results show alternation of tectonic compressional and extensional regimes. The Ordos Basin and its surroundings were in weak N-S to NNE-SSW extension during the Early to Middle Jurassic, which reactivated E-W-trending basement fractures. The tectonic regime changed to a multi-directional compressional one during the Late Jurassic, which resulted in crustal shortening deformation along the marginal zones of the Ordos Basin. Then it changed to an extensional one during the Early Cretaceous, which rifted the western, northwestern and southeastern margins of the Ordos Basin. A NW-SE compression occurred during the Late Cretaceous and caused the termination of sedimentation and uplift of the Ordos Basin. This phased evolution of the late Mesozoic tectonic stress regimes and associated deformation pattern around the Ordos Basin best records the changes in regional geodynamic settings in East Asia, from the Early to Middle Jurassic post-orogenic extension following the Triassic collision between the North and South China Blocks, to the Late Jurassic multi-directional compressions produced by synchronous convergence of the three plates (the Siberian Plate to the north, Paleo-Pacific Plate to the east and Lhasa Block to the west) towards the East Asian continent. Early Cretaceous extension might be the response to collapse and lithospheric thinning of the North China Craton.  相似文献   

遥感技术在西藏班戈地区构造研究与找矿预测中的运用          下载免费PDF全文

张杨  高光明 《地质找矿论丛》2011,26(2):217-221

西藏班戈地区的遥感地质调查研究表明:该区发育菱形网结状构造;错那、东错、蓬错、巴木错呈明显的"多字形"斜列,应为统一应力场下形成的伸展断陷盆地,并受到后期右行活动破坏;在东卡错-东错菱形块体中央隆起内发现有较大规模的岩浆岩侵入,推测该隆起区下为一地幔热柱;由北向南出露有东巧蛇绿岩带、东错-蓬错蛇绿岩带、白拉-觉翁蛇绿岩...  相似文献   

树根桩在厂房扩建工程地基处理中的应用     

张亮  高峰 《岩土工程技术》2011,25(1):38-40

在苏南某工业厂房扩建工程中,为了妥善解决新旧熔炉区的不均匀沉降,通过多方案的比选,最终采用树根桩托换技术进行地基加固。并且对新旧熔炉区的基础进行了化学植筋连接和防渗漏处理。  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987111000429   总被引：1，自引：0，他引：1  

Xieyan Song  Yushan Wang  Liemeng Chen 《地学前缘(英文版)》2011,2(3):375-384

The three most crucial factors for the formation of large and super-large magmatic sulfide deposits are: (1) a large volume of mantle-derived mafic-ultramafic magmas that participated in the formation of the deposits; (2) fractional crystallization and crustal contamination, particularly the input of sulfur from crustal rocks, resulting in sulfide immiscibility and segregation; and (3) the timing of sulfide concentration in the intrusion. The super-large magmatic Ni-Cu sulfide deposits around the world have been found in small mafic-ultramafic intrusions, except for the Sudbury deposit. Studies in the past decade indicated that the intrusions hosting large and super-large magmatic sulfide deposits occur in magma conduits, such as those in China, including Jinchuan (Gansu), Yangliuping (Sichuan), Kalatongke (Xinjiang), and Hongqiling (Jilin). Magma conduits as open magma systems provide a perfect environment for extensive concentration of immiscible sulfide melts, which have been found to occur along deep regional faults. The origin of many mantle-derived magmas is closely associated with mantle plumes, intracontinental rifts, or post-collisional extension. Although it has been confirmed that sulfide immiscibility results from crustal contamination, grades of sulfide ores are also related to the nature of the parental magmas, the ratio between silicate magma and immiscible sulfide melt, the reaction between the sulfide melts and newly injected silicate magmas, and fractionation of the sulfide melt. The field relationships of the ore-bearing intrusion and the sulfide ore body are controlled by the geological features of the wall rocks. In this paper, we attempt to demonstrate the general characteristics, formation mechanism,tectonic settings, and indicators of magmatic sulfide deposits occurring in magmatic conduits which would provide guidelines for further exploration.  相似文献   

Structural style in a young flexure-induced oblique extensional system,north-western Bonaparte Basin,Australia     

《Journal of Structural Geology》2015

In the north-western Bonaparte Basin (North West Shelf of Australia) Neogene to Recent flexure-induced extension superimposed obliquely over the Mesozoic rift structures. Thus, the area offers a good opportunity to investigate the dynamics and architecture of oblique extension fault systems. Analysis of basin-scale 2D and 3D seismic data along the Vulcan sub-basin shows that Neogene deformation produced a new set of extensional, en échelon faults, at places accompanied by the reactivation of the Mesozoic faults. The pre-existing Mesozoic structures strongly control the distribution of the Neogene-Recent deformation, both at regional and local scales. Main controls on the Neogene-Recent fault style, density and segmentation/linkage include: (1) the orientation of the underlying Mesozoic structures, (2) the obliqueness of the younger extension relative to the rift-inherited faults, and (3) the proximity to the Timor Trough. Three types of vertical relationships have been observed between Mesozoic and Neogene-Recent faults. Hard linkages seems to develop when both fault systems trend parallel, therefore increasing risks for trap integrity. It is suggested that the orientation of maximum horizontal stress (S_Hmax) relative to the Mesozoic faults, forming hydrocarbon traps, is critical for their potential seal/leak behaviour. Stratigraphic growth across the faults indicates that main fault activity occurred during the Plio-Pleistocene, which corresponds to the timing of tectonic loading on Timor Island and the development of lithospheric flexure. Synchronism of normal faulting with flexural bending suggests that extensional deformation on the descending Australian margin accompanied the formation of the Timor Trough.  相似文献