多坐标系中心组合图在地球信息图谱化中的应用     

李仁杰  张军海  傅学庆  谷宝庆 《测绘科学》2007,32(3):49-51

本文用典型实例验证了斜角坐标系量化图形中的多坐标系中心组合图展现地球信息图谱的优势和特点。这类图形以其“多坐标系”的特点和多种多样的组合形式,能够承载更大量的信息、更易反应数据内在规律。通过选择最佳的图形类型,对地球信息进行高效传输,通过图形使宏观的地学自然规律变得清晰可见,提供地学信息图谱的一种新展现手法。  相似文献   

Rare earth element geochemistry of the Woxi W–Sb–Au deposit, Hunan Province, South China     

Xuexiang Gu  Oskar Schulz  Franz Vavtar  Jianming Liu  Minghua Zheng  Shaohong Fu 《Ore Geology Reviews》2007,31(1-4):319

The Woxi W–Sb–Au deposit in Hunan, South China, is hosted by Proterozoic metasedimentary rocks, a turbiditic sequence of slightly metamorphosed (greenschist facies), gray-green and purplish red graywacke, siltstone, sandy slate, and slate. The mineralization occurs predominantly (> 70%) as stratabound/stratiform ore layers and subordinately as stringer stockworks. The former consists of rhythmically interbedded, banded to finely laminated stibnite, scheelite, quartz, pyrite and silty clays, whereas the latter occurs immediately beneath the stratabound ore layers and is characterized by numerous quartz + pyrite + gold + scheelite stringer veins or veinlets that are typically either subparallel or subvertical to the overlying stratabound ore layers. The deposit has been the subject of continued debate in regard to its genesis. Rare earth element geochemistry is used here to support a sedimentary exhalative (sedex) origin for the Woxi deposit. The REE signatures of the metasedimentary rocks and associated ores from the Woxi W–Sb–Au deposit remained unchanged during post-depositional processes and were mainly controlled by their provenance. The original ore-forming hydrothermal fluids, as demonstrated by fluid inclusions in quartz from the banded ores, are characterized by variable total REE concentrations (3.5 to 136 ppm), marked LREE enrichment (La_N/Yb_N = 28–248, ∑LREE/∑HREE = 16 to 34) and no significant Eu-anomalies (Eu/Eu = 0.83 to 1.18). They were most probably derived from evolved seawater that circulated in the clastic sediment pile and subsequently erupted on the seafloor. The bulk banded ores are enriched in HREE (La_N/Yb_N = 4.6–11.4, ∑LREE/∑HREE = 3 to 14) and slightly depleted in Eu (Eu/Eu = 0.63 to 1.14) relative to their parent fluids. This is interpreted as indicating the influence of seawater rather than a crystallographic control on REE content of the ores. Within a single ore layer, the degree of HREE enrichment tends to increase upward while the total REE concentrations decrease, reflecting greater influence and dilution of seawater. There is a broad similarity in chondrite-normalized REE patterns and the amount of REE fractionation of the banded ores in this study and exhalites from other sedex-type polymetallic ore deposits, suggesting a similar genesis for these deposits. This conclusion is in agreement with geologic evidence supporting a syngenetic (sedex) model for the Woxi deposit.  相似文献   

云南中基性火山岩风化壳离子吸附稀土成矿作用分析 ——以腾冲龙井山安山岩风化壳型稀土矿床为例     

曾招金  祝向平  张彬  高儒东 《地球学报》2021,42(6):936-944

近年来在云南发现了多个离子吸附型稀土矿,特别是滇西的腾冲—陇川地区、临沧—勐海地区成为了找矿突破最大、最受关注的地区.本次工作在腾冲火山岩带南部龙井山发现一套富含轻稀土的第四系中基性火山岩建造,该含矿建造稀土元素丰度平均值达532×10–6.经过系统的调查研究及采样工作,结果表明腾冲龙井山新近纪中的辉石安山岩富含轻稀土,为一种年轻火山岩形成的风化壳型稀土矿床,矿体平均厚度9.15 m,平均品位(TREEO)0.11％,矿体品位、厚度变化与风化壳厚度呈正相关.该中基性火山岩离子吸附型稀土矿床的发现丰富了云南稀土矿床类型.这种年轻的中基性火山岩型稀土矿的成矿地质背景、地球化学特征等,为寻找中基性岩有关的稀土矿床提供参考.  相似文献   

基于PCA-SVM算法对稀土元素与稀土判别指标耦合数据集的铀矿床分类     

刘云鹏  郭春影  秦明宽  吴玉  裴柳宁 《吉林大学学报(地球科学版)》2021,51(3):723-733

不同类型铀矿床的沥青铀矿/晶质铀矿具有不同的稀土元素组成,其组成可作为判别铀矿床类型的重要指标。采用基于Python语言的主成分分析（principal component analysis,PCA）与支持向量机（support vector machines,SVM）结合的分类模型,对收集到的全球已知6种类型铀矿床的216组沥青铀矿/晶质铀矿稀土元素数据进行研究。以216组数据为训练集,通过数据清洗、特征缩放、PCA特征提取、网格搜索和交叉验证参数寻优构建SVM分类模型,对24组同变质型胡家峪晶质铀矿进行智能识别。研究结果显示：仅使用稀土元素的14维训练集最优模型判定胡家峪晶质铀矿类型的测试准确率为0.4%;由稀土元素、稀土总量、轻重稀土比、铕异常组成的17维训练集最优模型的测试准确率为75.0%,较14维训练集提高74.6%,模型泛化能力强;而通过传统稀土元素配分曲线、w（ΣREE）-（LREE/HREE）_N图解不能有效判定胡家峪晶质铀矿类型。本次研究表明,PCA-SVM算法对增有传统稀土判别指标数据集进行挖掘可有效厘定铀氧化物成因类型,效果明显优于单纯的稀土元素数据集以及传统的稀土配分曲线、w（ΣREE）-（LREE/HREE）_N图解。  相似文献   

黏性土中静压桩沉桩过程现场试验及桩土界面桩侧土压力分析     

王永洪  桑松魁  张明义  李长河  韩勃  袁炳祥  项俊宁  王振杰  刘慧宁 《吉林大学学报(地球科学版)》2021,51(5):1535-1543

为了揭示黏性土中静压桩贯入过程中桩土界面桩侧土压力的受力特性,依托山东东营某桩工程开展了现场足尺试验,得到了静压桩沉桩过程中桩土界面桩侧土压力随贯入深度的变化规律,分析了贯入过程中不同土层桩侧土压力的分布特性,明确了桩侧土压力在沉桩过程中存在明显的退化效应,探讨了桩土界面桩侧土压力与桩侧上覆土体竖向土压力的比值关系。结果表明：桩土界面桩侧土压力与土层性质密切相关;随着传感器贯入深度的逐渐增加,桩侧土压力逐渐增大,并且增大幅度随土层的不同而不同;在同一贯入深度处,桩土界面桩侧土压力存在明显的退化现象,粉土中的退化幅度明显小于粉质黏土中的退化幅度;同一土层中桩土界面桩侧土压力与桩侧上覆土体竖向土压力的比值为常数,并且粉土中的比值明显大于粉质黏土中的比值。  相似文献   

都龙锡锌多金属矿床稀土元素地球化学特征及指示意义          下载免费PDF全文

滕浪  陈守余  赵江南  陈俊霖  胡振  田光礼 《地质找矿论丛》2018,33(4):507-516

都龙锡锌多金属矿床属于滇东南有色金属矿产带的重要组成部分,主要矿石类型为锡石硫化物—矽卡岩型,化学成分和矿物组合比较复杂,具有多期成矿的特点。为了进一步了解矿区成岩成矿过程,本文对该区花岗岩、大理岩、矽卡岩、矿石和片岩的稀土元素特征进行了系统研究,结果表明：区内花岗岩属于地壳硅铝层部分熔融进而通过结晶分异作用形成的复式花岗岩,成矿物质来源于地壳深部岩浆;各元素特征和稀土元素变异图表明矿石和矽卡岩、花岗岩具有同源性;矿石具Eu正异常,其反映成矿过程中有高温流体的参与,形成于氧化环境。  相似文献   

REE,Fe and Mn Contents of Calcites and Their Prospecting Signi¬ficance for the Banqi Carlin-type Gold Deposit in Southwestern ChinaEI北大核心CSCD     

Wang J.  Han Z.  Li C.  Gao Z.  Yang Y.  Zhou G. 《大地构造与成矿学》2018,(3):494-504

The Banqi gold deposit is one of the important Carlin-type gold deposits in the southwestern Guizhou Carlin-type gold district, and it is the first deposit of the type found in China. As the major gangue mineral in this deposit, calcite can be divided into four types based on their formation time: pre-mineralization, main metallogenic epoch, late stage of mineralization, and post-mineralization. All types of calcites have distinct features such as field occurrence, physical typomorphic characteristics and trace elements characteristics. The pre-mineralization calcites have the highest REE contents (∑REE=29.70-40.10 μg/g), which are characterized by the most enriched LREE (LREE/ HREE=1.96-3.03), a distinct positive Eu anomalies (δEu=3.83-5.02), and almost no Ce anomalies (δCe=1.02-1.05). The calcites of the main metallogenic epoch have relatively low REE contents (∑REE=10.76-15.53 μg/g), and are characterized by the most enriched HREE (LREE/HREE=0.11-0.23), almost no Eu (δEu=0.73-1.20) and Ce anomalies (δCe=0.88-1.25). The calcites of the late stage of mineralization have the lowest REE contents (∑REE=2.82-4.34 μg/g), and are characterized by enriched HREE (LREE/HREE=0.26-0.86), weakly negative Eu (δEu=0.67-0.83) and Ce anomalies (δCe=0.55-0.81), which are similar to those of the calcites of the main metallogenic epoch. The post-minera¬lization calcites have relatively low REE contents (∑REE=6.92-10.91 μg/g), characterized by enriched LREE (LREE/HREE=1.83-2.34), weakly negative Eu anomalies (δEu=0.72-0.74) and moderately negative Ce anomalies (δCe=0.41-0.50). In addition, the Fe and Mn contents of ore-forming stage calcites are obviously higher than that of the calcites unrelated to mineralization, and negatively correlated with LREE/HREE ratio, which illustrates that the HREE concentrations of calcites are controlled by the incorporation of Fe and Mn. Thus, it will provide an important exploration indicator for the Yunnan-Guizhou-Guangxi Carlin-type gold deposits through the study of typomorphic characteristics of calcite. © 2018, Science Press. All right reserved.  相似文献   

四川盆地西南部中二叠统白云岩成因分析——来自锶同位素、稀土元素证据     

冯轲  徐胜林  陈洪德  董翼昕 《中国岩溶》2018,37(5):659-670

白云岩作为优质的油气储层,其成因一直是沉积学研究热点,通过地球化学分析揭示其流体性质是探究白云岩成因的重要途径。本文通过对川西南中二叠统典型剖面和钻井的碳酸盐岩样品进行岩石学、稀土元素和锶同位素特征研究,分析结果显示:（1）其岩石类型主要有石灰岩、泥微晶白云岩、细-中晶白云岩和鞍形白云石4种。（2）研究区白云岩锶同位素比值（平均值0.709 77）明显高于石灰岩和同期海水,接近全球壳源锶同位素平均比值,显示白云岩化流体是热液来源,同时部分泥微晶白云岩显示海水锶同位素特征。（3）研究区碳酸盐岩相较于同期海相沉积物有较高的δCe值（平均值0.86）,显示其开放的成岩环境。（4）3种类型的白云岩相较于石灰岩有较高的δEu值（平均值0.99）和显著不同的稀土总量特征,显示研究区白云岩与石灰岩成岩流体性质不同且白云岩受到高温影响。综合分析表明,川西南地区白云岩主要是受构造控制的热液白云岩,部分为被岩浆和热液加热的海水改造的热对流白云岩。   相似文献   

Application of Rare Earth Elements of the Marine Carbonate Rocks in Paleoenvironmental Researches     

Yuhang Wang  Yuanyuan Zhu  Jiandong Huang  Huyue Song  Yong Du  Zhe Li 《地球科学进展》2018,33(9):922-932

The pattern, contents and ratios of Rare Earth Elements (REE) from marine carbonates play an important role in the paleo-environmental researches. As result of the REE's source being variable, which includes marine carbonates, detrital input and diagenesis, the overall assessment for the reliability of REE's data is necessary. Furthermore, appropriate analytical method is vital for the reliable contents of REE. This paper reviewed the geochemical properties, analytical and data processing methods, feasibility verification and paleo-environmental application of carbonates REE. The patterns of REE, which provide theoretical basis for the provenance and depositional environment of carbonates, are various with different sources. Cerium, as a redox sensitive element, is a key proxy for the reconstruction of paleo-redox conditions. There are two available analytical methods, acid-leaching method and direct LA-ICP-MS analytical method, to extract REE of seawater preserved in marine carbonate rocks. The contamination from detritus and diagenetic alteration can be detected by the correlations of various elements or element ratios. The REE of marine carbonate has been well applied to reconstruct the environment changes during the Precambrian, Permian-Triassic transition and Cenozoic.  相似文献   

高压密闭消解-电感耦合等离子体质谱法测定锰矿石中的稀土元素前处理方法研究   总被引：4，自引：4，他引：0  

吴磊  刘义博  王家松  吴良英  张楠  王娜 《岩矿测试》2018,37(6):637-643

高压密闭消解因称样量小、用酸量少、空白低等优点成为测定稀土元素前处理的主要方法。但锰矿石组分复杂,锰含量差别较大且具有多种不同价态,常含有伴(共)生金属和其他杂质,该方法采用常规酸溶体系很难将其消解完全,造成ICP-MS测试结果不准确。本文从样品前处理消解效果出发,选择锰矿石标准物质GBW07261、GBW07263、GBW07266和一个锰矿石样品,试验了三种酸溶前处理方法对锰矿石稀土元素测试的影响。结果表明:方法一(氢氟酸-硝酸密闭消解,硝酸复溶提取)不能将锰矿石样品完全消解,测定值偏低0. 28%～61. 31%;方法二(氢氟酸-硝酸-双氧水密闭消解,硝酸-双氧水复溶,硝酸提取)和方法三(氢氟酸-硝酸密闭消解,盐酸复溶,硝酸提取)均可将锰矿石样品消解完全,用ICP-MS测定稀土元素的数据较为接近,与传统的过氧化钠熔融ICP-MS法测定值吻合。但实验过程中发现对于锰含量较高的样品,方法三需多次重复加入盐酸复溶后方可将样品消解完全,而方法二复溶一次即可。因此,方法二对锰矿石样品的消解效率更高,精密度好(0. 96%～2. 68%),加标回收率在95. 0%～107. 0%之间,更适用于锰矿石中稀土元素的分析。  相似文献