Modelling nitrogen and phosphorus cycles and dissolved oxygen in the Zhujiang Estuary Ⅰ. Model development

wrmcrloxHuman activities related to the population growth and developrnent of industry and rnwhci-pality have led to the incrouing hadings of various POllutants into estudries during the past fewdecades. These increasing edlutant lOadings have caused declined estuallne hedth which can bemereured by a vdriety of indices. In order to obtain solutions to environrnent problerns, re-sources manageTnnt apencies are supporting a holistic approach to envirorirnental management.An effcient strategy t…     

Modelling nitrogen and phosphorus cycles and dissolved oxygen in the Zhujiang Estuary Ⅰ.Model results

rmIoxThe averag annual dischaIge of the Zhujiang Xiver is 3. 32 x l0ll m3, which ranks theZhujiang River just end to the Changjiang River in China. The dischnye occutring duringthe fltal m between APril and ffepteTnber accounts for 80% of the yearly total. The Zhu-jiang hiver has a yeaIy sediment load of about 1 x l08 tons, which also concentrates in theM arn (Zhao, l990; Chen et al., 1998). The Zhujiang Xiver delta,which has l2 cities ofdifferent sizes and more than 40 towns with a po…     

粤东北桃源铀矿床黄铁矿地球化学特征及其地质意义

粤东北桃源铀矿床位于华南铀成矿省武夷山铀成矿带,其矿床成因、成矿物理化学环境特征等还未开展深入研究。黄铁矿的地球化学特征往往能够有效地反映其形成时的地球化学环境。桃源铀矿床中黄铁矿与沥青铀矿成因关系密切。因此笔者在野外地质调查和岩相学基础上,利用LA- ICP- MS原位分析技术,对桃源矿床黄铁矿主、微量元素开展研究。结果表明：①黄铁矿主量元素w（Fe）=41.64% ~ 49.39%,平均值为45.83%;w（S）=50.56% ~ 57.62%,平均值为53.73%,w（Fe）/w（S）=0.73 ~ 0.98,平均值为0.85,表明其形成环境是一个微弱缺铁,相对富硫的相对封闭的地球化学环境;②黄铁矿中相对富集Si、Na、Al、K、Ca、Cr、Co、Ni、Ti、Cu、Ge、As、Se、Bi、Pb等微量元素;③绝大多数微量元素与主量元素Fe、S无明显线性关系,表明在黄铁矿形成过程中,这些微量元素的地球化学行为除受到类质同象因素的影响外,还受其他因素影响;④成矿元素U与部分微量元素显示出较好的正相关关系,其中Na、Ti等元素含量高表明与铀矿物在空间上紧密相关的黄铁矿形成于成矿早期的碱性热液蚀变阶段,而非成矿期,要早于铀成矿时间,并为铀成矿提供还原剂;⑤黄铁矿内部微裂隙发育,成矿期铀矿物容易进入其中,从而引起裂隙附近铀矿含量升高。伴随的高含量As表明其形成于中低温热液环境。     

下庄竹山下铀矿床黄铁矿元素地球化学特征及其表征意义

竹山下铀矿床是粤北下庄铀矿田内大型铀矿床之一,铀矿化类型为"交点"型和硅化带型。在详细的野外地质调查基础上,对竹山下铀矿床4种不同类型黄铁矿进行元素含量分析及硫同位素测试,结果表明:"交点"型矿石中黄铁矿相对富集Pb、 Cu、 Co、 As、 Ni、 Se、 Bi、 U、 Sb、 Zn等微量元素;"交点"型铀矿化形成于中深部高温环境,成矿热液具有地幔流体特征,成矿过程硫来源与该区花岗岩中黄铁矿的硫来源一致或者相似,花岗岩中的黄铁矿可能为该期成矿事件的产物;竹山下矿床在垂向上表现出越往深部硫逸度越低的特征;"交点"型和硅化带型中黄铁矿具有相似的微量元素配分曲线,表明二者具有相同的成矿热液来源,且与辉绿岩中黄铁矿配分曲线相似,表明该区成矿热液具有深源性。     

高阶非线性完全频散性波浪数值模型及应用

为更精确地模拟强非线性完全频散性波浪的传播,采用长波上非线性重力表面波传播高阶数学模型,综合参考此模式已有的研究成果,建立了一个高达五阶的完全频散性非线性数值模型。应用该五阶模式对斜坡地形、潜堤地形及正弦沙链地形进行模拟计算,并与已有的实验资料进行对比,结果显示五阶模式较低阶模式模拟结果的精度上有了明显提高,模拟波形与实验结果吻合度良好,证明高阶模式更适用于高频散高非线性波浪传播的数值模拟。     

后压浆方案的技术可行性论证

从地层选择、效果预测、经济分析和施工应用４个方面对钻孔灌注桩后压浆方案进行可行性论证,并对承载力增幅进行了分析。     

Hydrocarbon generation and expulsion characteristics of Lower Permian P1f source rocks in the Fengcheng area,northwest margin,Junggar Basin,NW China: implications for tight oil accumulation potential assessment

Combined with the actual geological settings, tight oil is the oil that occurs in shale or tight reservoirs, which has permeability less than 1 mD and is interbedded with or close to shale, including tight dolomitic oil and shale oil. The Fengcheng area (FA), at the northwest margin of the Junggar Basin, northwest China, has made significant progress in the tight oil exploration of the Fengcheng (P₁f) Formation recently, which indicates that the tight oil resources have good exploration prospects. Whereas the lack of recognition of hydrocarbon generation and expulsion characteristics of Permian P₁f source rocks results in the misunderstanding of tight oil resource potential. Based on the comprehensive analysis of geological and geochemical characteristics of wells, seismic inversion, sedimentary facies, tectonic burial depth, etc., the characteristics of P₁f source rocks were investigated, and the horizontal distributions of the following aspects were predicted: the thickness of source rocks, abundance and type of organic matter. And on this basis, an improved hydrocarbon generation potential methodology together with basin simulation techniques was applied to unravel the petroleum generation and expulsion characteristics of P₁f source rocks in FA. Results show that the P₁f source rocks distribute widely (up to 2039 km²), are thick (up to 260 m), have high total organic content (TOC, ranging from 0.15 to 4 wt%), are dominated by type II kerogen and have entered into low mature–mature stage. The modeling results indicate that the source rocks reached hydrocarbon generation threshold and hydrocarbon expulsion threshold at 0.5% Ro and 0.85% Ro and the comprehensive hydrocarbon expulsion efficiency was about 46%. The amount of generation and expulsion from the P₁f source rocks was 31.85 × 10⁸ and 15.31 × 10⁸ t, respectively, with a residual amount of 16.54 × 10⁸ t within the source rocks. Volumetrically, the geological resource of shale oil is up to 15.65 × 10⁸ t. Small differences between the amounts calculated by the volumetric method compared with that by hydrocarbon generation potential methodology may be due to other oil accumulations present within interbedded sands associated with the oil shales. Copyright © 2015 John Wiley & Sons, Ltd.     

歧口凹陷歧深地区沙三段层序地层格架及其演化

在对钻井、录井、测井、地震和各种测试资料的综合分析基础上,对沙三段层序地层格架进行了系统的研究。共识别出4个层序界面,3个三级层序,并在各三级层序内识别出低位体系域、湖扩体系域和高位体系域。认为深凹及控凹断裂边缘3个体系域发育完整,而板桥及歧北次凹斜坡带仅发育退积型湖扩体系域和进积型高位体系域。在此基础上,建立了歧深地区层序地层发育模式——陆相单斜断坡带型(西断东缓超)地层格架,为研究区有利储集体的预测提供了基础。     

中国大陆沿岸波浪能分布初步研究

波浪能作为可持续利用的清洁能源,日益被人们所关注,本文基于WAVEWATCHⅢ全球波浪模式,建立了较高精度的中国沿岸海域波浪数学模型,重点对中国大陆沿岸-30m等深线上的波浪能分布进行了研究,在已有研究成果的基础上进一步细化了中国沿岸海域波浪能的时空分布规律,为合理开发、利用波浪能提供了一定的数据支持。研究认为,中国沿岸波浪能储量相对较小,南北分布以长江口为界,以南海域波能整体较大,波能季节性差异明显,在开发利用时,需要对工程区域的波浪能特征充分论证,科学合理地选用波浪能转化设备,防止造成巨大经济损失。     

高山冰川多时相多角度遥感信息提取方法

提出一种多角度遥感影像的冰川信息提取方法。通过"全域—局部"的阈值分割方法获取短时期内不同时相的遥感影像的冰雪边界,结合地形信息和多时相遥感影像的太阳角度信息,联合消除山体阴影对冰川的遮挡,并以多期影像的最小冰雪边界作为最佳冰川边界。以托木尔峰西侧冰川为研究对象,采用2009—2010年4个时相的遥感影像提取冰川信息。结果表明多角度遥感提取的冰川边界效果好,能有效地排除积雪与山体阴影的干扰。