关于华北克拉通西北缘(狼山段)边界位置有那仁宝力格-获各琦-赛乌素断裂和查干毛道-甘其毛道断裂存在两种观点.为确定边界位置,本文通过对比那仁宝力格-获各琦-赛乌素断裂两侧中新元古界形成时代、沉积环境及侵入岩Hf同位素,并结合地球物理场特征,确定克拉通应以宝音图群北侧的查干毛道-甘其毛道断裂为界线.那仁宝力格-获各琦-赛乌素断裂形成于晚古生代,具有分割两侧古生代地质体特征及演化历史的意义.该边界的确定为该区构造单元的划分及成矿规律的总结具有指导意义,同时提出东侧的白云鄂博-化德-多伦-赤峰断裂作为华北克拉通北缘边界是否合适.
霍西煤田是我国重要的焦煤产地,为了全面查明其煤质特征及成煤环境,本文以煤田南部的主采煤层(2、9(9+10)号)为研究对象,通过分析煤样的煤岩、硫分、灰分和灰成分等数据,评价其煤质特征,推断其成煤环境.研究表明:煤层镜惰比越高,沉积环境覆水越深;硫分含量越高,受海水影响越大;灰分含量越高,水动力越强;灰成分指数K值越大,还原型越强;CaO/MgO值越高,则成煤气候条件越潮湿;m值反映沉积环境是淡水还是咸水.根据2、9(9+10)号煤灰分低-中、灰成分指数低、1＜m＜10的特点,推断二者形成过程受河流搬运作用影响,为水动力较强、还原型、半咸水的沉积环境.对2层煤其他煤质特征分析,发现二者成煤环境存在差异,表现为:2号煤具有镜惰比(V/I)较低、硫分低、CaO/MgO值较高的特征,说明成煤环境为覆水不深、古气候环境潮湿的三角洲平原相泥炭沼泽环境;9(9+10)号煤具有镜惰比(V/I)中等偏高、硫分高、CaO/MgO值高的特征,说明成煤环境为强覆水、受海水影响、古气候环境极潮湿的泻湖相泥炭沼泽环境.
本文旨在探讨利用稳定同位素手段揭示高氟地下水的起源、循环和演化过程,通过收集和整理已有的相关研究成果,对氢氧同位素、锶钙同位素和锂硼同位素在高氟地下水研究中的应用进行综述.研究发现,地下水中的δ2H和δ18O值可以确定水的来源和混合过程,并进而识别高氟地下水的潜在来源.锶钙同位素在高氟地下水研究中备受关注,通过获取地下水中的87Sr/86Sr比值和δ44/40Ca,可以揭示矿物风化溶解、阳离子交换、次生矿物相沉淀等水文地球化学过程,对于理解高氟地下水的形成机制和演化过程至关重要.另外,锂硼同位素也是研究高氟地下水的重要工具之一,通过测量δ7Li和δ11B值,可以判断地热流体对深层高氟地下水的影响.综上所述,稳定同位素在高氟地下水研究中具有广泛应用前景.通过测量氢氧同位素、锶钙同位素和锂硼同位素,我们可以深入了解高氟地下水的起源、循环和演化过程,从而为高氟地下水治理和水资源管理提供科学依据,为制定相应的防治措施和保障人类健康提供重要支持.
埕宁隆起区属于典型的层状热储,地热井口水温往往小于60℃,但是以山东省宁津县相衙镇为代表的深部岩溶热储,水温却高达78～82℃,存在明显的高水温异常.本文在收集以往研究成果的基础上,采用地热地质专项调查、地球物理勘探、岩矿测试等工作手段,初步查明了断裂构造是引起区内深部岩溶热储高水温的主控因素,并明确热源、水源、盖层、通道、热储层各个相关因子,从而建立热储概念模型,为区内深部岩溶热储地热资源的合理开发提供指导意义.
柴达木盆地西北缘中新生代坳陷区是砂岩型铀矿成矿的有利地区.为查明盆地内铀矿赋存情况,对柴达木盆地西北缘的主要油气田区钻孔开展了放射性异常筛查,发现大部分油气田区存在放射性异常,且具有多个异常层位,主要包括第四系、新-古近系、侏罗系,异常层位埋深45～1 000m.通过对优选的放射性异常钻孔进行验证,在跃进地区第四系七个泉组、新近系上油砂山组的砂岩层中发现工业矿体,为盆内寻找砂岩型铀矿提供了新的找矿线索.
山西省矿产资源非常丰富,煤矿、铝土矿和铁矿等大宗紧缺矿产是其优势矿产.随着社会经济不断发展,对矿产资源需求量不断增长,矿产资源开发速度亦加快,与此同时矿山开发对生态环境造成很大的破坏,矿业开发和环境保护之间的矛盾逐渐加剧.利用遥感影像与ArGIS相结合,开展矿山开采监测工作,不仅可以为相关执法部门提供可靠的数据,而且对于规范区域矿山开发秩序、保护生态环境具有非常重要的意义.文章结合山西省矿山开采遥感数据解译工作,建立矿山解译标志,并提出矿山开采存在的问题,为相关矿政管理等工作提供参考.
为了探究华北地区地下咸水资源科学、合理的利用方式,本文通过开展冬小麦咸水灌溉的田间试验,采用地下咸水和淡水灌溉两种方式,研究了咸水灌溉对土壤水盐运移及小麦产量的影响.结果表明,同一灌溉量下,淡水灌溉水分运移深度较咸水灌溉深,且同一深度淡水灌溉土壤含水率明显高于咸水,咸水灌溉在一度程度上会影响土壤入渗和持水能力;咸水灌溉随着持续灌溉,土壤表层(0～0.2m)和深层(0.6～1.2m)盐分开始积聚,整个播种收获期,土壤剖面含盐量产生不同程度累积,埋深0.4 m盐分累积量达到峰值1.6 g/kg.淡水灌溉对土壤含盐量影响较小,但会将表层土壤盐分淋洗至深层累积;当灌溉水矿化度为8.69 g/L,冬小麦产量减少达37.65％.因此,在开展咸水灌溉时,应合理控制灌溉水的矿化度,实行咸淡混合灌溉,在小麦不减产情况下最大限度利用咸水资源.
地下空间的开发利用是新时代实现城市经济与社会、资源、环境可持续协调发展的必经之路.为了客观评价雄安新区土体可利用属性的重要性,基于粗糙集理论,探讨了雄安新区地下空间50m以浅不同深度范围(0～5 m、5～30 m和30～50m)内常见的工程类型以及土体可利用性的影响因素,并对土体可利用性的影响因素进行了重要性评价,得出了影响土体可利用属性的重要度和权重值.结果表明:(1)雄安新区地基土的工程地质性质总体良好,适宜大规模建设,但仍需关注人工填土层(杂填土、素填土)、软弱土层(淤泥质粉质粘土、软塑粉质粘土)、液化土层(粉土、粉细砂)、地下水位、坑塘等不良的工程地质特性;(2)得出了土体可利用属性的重要性排序:0～5 m依次为地基承载力、杂填土厚度、粉土层厚度、砂土层厚度、坑塘分布、地下水位,5～30 m依次为淤泥质层厚度、地下水位、粉土层厚度、砂土层厚度、地基土均匀性,30～50 m依次为地下水位、砂土层厚度、粉土层厚度;(3)粗糙集理论能够客观地评价雄安新区地下空间土体可利用性,从知识表达系统中挖掘影响因素之间的内在规律,得到客观可靠精细的重要度和权重值,为雄安新区地下空间土体的开发利用提供了评价依据.
本文通过分析湖南省某个典型矿区地下水水文地球化学调查数据,依托健康风险评价机制(Health Risk As-sessment,HRA)评估了男性和女性在不同暴露途径下的健康风险,主要评价指标包括致癌物质砷(As),非致癌化学有毒物钴(Co)、锰(Mn)、钼(Mo)、硒(Se)和钡(Ba),可能致癌物质锑(Sb)等,结果表明,矿区地下水监测点的重金属含量会对人体造成一定的健康风险,其中女性的健康风险值比男性风险值更大,女性健康风险总值的最大值和最小值分别为1.69、6.37E-03,男性分别为4.36E-2、1.75E-03.研究区中锑(Sb)元素对人体造成的非致癌健康风险值最大,钴(Co)元素的非致癌风险值最小.致癌物质砷(As)对男性和女性造成的致癌风险均值为1.73E-02、1.80E-02,超过可接受范围的10倍,且男性和女性皆仅有6处水样点处于最大终身可接受风险水平之内.综上所述,研究区地下水水文地质化学指标造成的人体健康风险整体非常高,其中锑、砷的污染最为严重.
铀成矿年龄是砂岩型铀矿研究中的热点与难点,为了深入认识鄂尔多斯盆地砂岩型铀矿的时空分布规律,本文对全岩U-Pb定年、电子探针法EMPA、LA-ICP-MS、fs-LA-ICP-MS、SIMS等方法的适用性和限制性进行了分析,统计和对比了盆地内20多个砂岩型铀矿床的成矿年龄、含矿层位信息,并以鄂尔多斯盆地东北部典型矿床为例,系统地分析了砂岩型铀矿成矿过程,结果显示,鄂尔多斯盆地砂岩型铀矿含矿层位主要为中侏罗统直罗组,下白垩统洛河组,其次为下白垩统马东山组、罗汉洞组,铀成矿时间大部分集中在中新世,与新生代构造事件有较好耦合.盆地东北部由东向西,东胜-纳岭沟-塔然高勒-大营-巴音青格利矿床中矿体海拔高度大致相当,而矿体在含矿层位中的相对位置则逐渐上升.反映出各矿体的形成均受近同期的成矿事件控制.鄂尔多斯盆地砂岩型铀矿成矿作用时间主要集中在中新生代且与新生代构造事件有较好耦合,东北部典型矿床中铀矿体产出在同一目的层的不同部位,均指示出铀成矿可能与新生代构造活动紧密相关.
本文报道了北山造山带蒜井子晚奥陶世花岗岩的LA-ICP-MS锆石U-Pb年龄与全岩地球化学,以探讨其形成时代、岩石成因及构造环境.蒜井子二长花岗岩LA-ICP-MS锆石U-Pb定年结果显示其形成于 456.3±3.5Ma.英云闪长岩具有低的 Si02(61.99％～66.62％)、ALK(4.66％～5.16％)、K20/Na20(0.52～0.64)和 A/CNK为 0.89～1.05,而二长花岗岩具有高的 Si02(71.93％～73.20％)、ALK(6.44％～6.89％)、K20(K20/Na20为 1.32～1.94)和 A/CNK(1.04～1.05),低的A/NK(1.49～1.64).该岩体富集轻稀土(LREEs)和大离子亲石元素(LILE)Rb、Th、K,亏损重稀土元素(HREEs)和高场强元素Nb、Ta、Ti,具有弱的负Eu异常.上述特征表明,研究区晚奥陶世花岗岩具有准铝质-弱过铝质钙碱性岩石的特征,属于高分异I型花岗岩,岩浆源区以壳源物质为主,有少量幔源物质的加入,形成的构造环境为岛弧.结合区域地质背景,认为北山洋在456.3±3.5 Ma之前已开始向北俯冲.
In this paper,geochemical analysis of the ore bearing metasedimentary rocks of the Tebai gold deposit in Alxa Right Banner is carried out,The main lithology is mica quartz schist,metamorphic siltstone,metamorphic lithic quartz sandstone,etc;The average content of SiO 2 is 62.39%,the average content of Al 2 O 3 is 15.40%,the average content of Fe 2 O 3 is 6.57%,the average content of MgO is 3.84%,the average content of CaO is 2.31%,the average content of K 2 O is 2.65%,the average content of Na 2 O is 2.09%.The REE patterns of curves are consistent,LREE/HREE=5.75～8.34,the average value is 7.18,（La/Yb） N =5.39～8.38,the average value is 6.83,Eu negative anomaly is obvious,LREE are obviously enriched relative to HREE;Rb-K 2 O diagram、Ni-TiO 2 diagram and La/Yb-ΣREE diagram show that the parent rocks may originate from granites;Combined with paleocurrent characteristics and detrital zircon age evidence,it is speculated that the provenance may come from granite in Beidashan area.Combined with the rock assemblage characteristics,tectonic combined characteristics and Geochemical characteristics of Ore bearing metasedimentary rocks in Tebai,it is considered that the source rocks were formed in a tectonic environment of continental island-arc.
The Bangyankeng,Duanxin and Qingshanling granitic plutons intrude in the eastern part of Jiangnan orogenic belt.The Bangyankeng pluton shows high SiO 2 content（65.56%～71.36%）,rich in aluminum（Al 2 O 3 =14.12%～16.58%）,and poor in MgO（1.08 to 1.33）.It is also rich in potassium（3.42%～4.56%）,and weak negative Eu anomaly（δEu=0.65～0.92）,（La/Yb） N has a higher value of 13.92～19.09.As the content characteristic element Y is with a low value of 13.8×10 -6 ～17.9×10 -6 .Sr is of 335.9×10 -6 ～484×10 -6 ,with the significant negative anomalies of Nb and Ti.Various characteristics indicate that Bangyankeng granite belongs to C-type adakites with the partial melting of mafic crust formation.The DuanXin and Qingshanling granites are rich in Si,K,poor in Ca,Mg and peraluminous characteristics.The LREE and HREE exhibit moderate right orientation,strong negative anomalies of Eu.It shows classic right-slope"V"shape.The incompatible elements Rb,Th,Ta are high and Zris slight loss.Ba,Sr,Eu show strong negative anomaly,together with Ga/Al=3.12～3.44.The geochemistry indicates that DuanXin and Qingshanling rock belong to A 2 -type granite,as the product of postorogenic extensional.The crust in northeast of Jiangxi was thickened after the Indosinian orogeny and then suffer the regional tectonic stress shifts during the Late Jurassic to Early Cretaceous.The compression under the tectonic thickening transfers to the post-orogenic extension.
The Karoo Supergroup in Tanzania represent the earliest Phanerozoic deposition. The stratum is generally continuous, mainly formed in a series of half graben-graben basins that caused by rifting. Based on the comprehensive study of the regional geological distribution, lithologic composition, sedimentary environment analysis and the pollen biological characteristics,the sedimentary sequence, sedimentary facies and the age of sedimentation of each group, section of the Karoo supergroup are systematically studied. The ore-bearing characteristics of this stratum is summarized. According to the study, the lithology of the Karoo Supergroup in Tanzania is generally represented by a suite of sandstone-shale. The deposition time span is from the Late Permian to the Early Cretaceous, and the sedimentary environment from bottom upward is the glacial facies, lake facies and river facies. It is comparable to the typical Karoo Supergroup in South Africa. It also shows good mineralization potential of coal mines and sandstone-type uranium deposits; meanwhile, there are many oil and gas resources, graphite prospecting clues.
Tin resources are abundant in North China, especially in the middle and southern Greater Khingan Range, which is one of the three major tin mining areas in our country and the only formed tin polymetallic ore belt found in the north of China. The types of tin deposits in North China are mainly divided into three categories: hydrothermal, porphyry and contact account type, most of which are co-occurring and associated deposits, with few independent tin deposits. The mineralization period of tin deposits in the region is mainly concentrated in the Late Jurassic-Early Cretaceous. On this basis, the main ore-controlling factors of tin deposits in North China were analyzed, the metallogenic models of contact metasomatic, porphyry and hydrothermal tin deposits were initially established, and the temporal and spatial distribution of tin deposits were discussed, and Xilinhot-Keshiketeng Banner, Erlian-Dongwu Banner and Shangdu-Taipusi Banner are key areas for searching for tin deposits in North China.
The East African Rift is the most typical continental rift in the world. It is generally believed that the rift consists of two parts: the East Branch and the West Branch. By summing up the previous research results, this paper discusses the relationship between the evolution of the East African Rift and the mantle plume in terms of geophysics, petrology and geochemistry. The models correspond to magmatism with different geochemical properties in northwest Ethiopia and Turkana, respectively. Finally, the possible patterns of the mantle plume under the East African Rift were discussed.
In recent years, 49 chromite deposits（ore occurrences） including 1 medium-sized deposit, 11 smallsized deposits and 37 occurrences have been discovered in North China. These chromite deposits（occurrences）are mainly distributed in Inner Mongolia, Hebei, Henan and Beijing provinces,which strictly controlled by Ophiolites and distributed spatially along the ophiolite belts, such as Shangdan, Suolunshan and Hegenshan. They were formed in Archen to Mesozoic, and Neoarchean-Paleoproterozoic and Late Paleozoic were heyday period of chromite mineralization. The ophiolite type is mainly chromite deposit type, followed by magmatic type. The comprehensive analysis shows that several ophiolitic melange belts such as Erlian-Hegenshan, Suolunshan,Kedanshan and Shangdan have good prospecting potential for chromite deposits in Inner Mongolia. Deep exploration and peripheral investigation of known mining areas should be strengthened to achieve a breakthrough in chromite prospecting.
Three-dimensional geological model plays an important role in geological prospecting and resource evaluation, and its quality determines the application potential and effect of the model. This paper reviews the research progress of 3D geological model quality evaluation at home and abroad, and systematically expounds the factors that affect the quality of 3D geological model, including the complexity of modeling geological objects, the accuracy and quality of modeling data sources, the methods of 3D geological modeling, and the expert knowledge of modeling personnel. At the same time, the paper analyzes the principle, advantages and disadvantages of the main methods of quality evaluation of 3D geological models, and holds that the quality evaluation of 3D geological models has gradually entered the era of quantitative evaluation from qualitative evaluation. Finally, this paper summarizes the problems existing in the research of 3D geological model quality assessment methods, and discusses its future development trend.
The border area between China and Mongolia developing various types of intrusive rock is an important part of the complex tectonic environment in the Central Asian orogenic belt. In the area, rock type and rock combination rich variety with a large age span. Discussing the temporal and spatial distribution characteristics and establishing intrusive rock framework has important significance in understanding the regional tectonic evolution and crust mantle activity. Taking the magmatic cycle as the main line, the paper compared the spatial and temporal characteristics of intrusive rock between the Lvliangian to the Yanshanian, that clearly reflects the "active" in the crust collision and suturing began in the Caledonian and reached its peak in the Variscan. This indicates that the crust gradually sutures from west to east. The orogenic process differ between western Altay orogenic belt and Eastern Xing’an Mongolian orogenic belt under different tectonic units. In addition, there are large-scale magmatic belts on both sides of the regional fault, and regional faults control the scope and scale of the intrusive rock significantly.
彭阳铀矿床位于鄂尔多斯盆地西南部天环坳陷南端,是我国在风成沉积中发现的第一个大型砂岩型铀矿.其含铀岩系为下白垩统洛河组,为一套沙漠相为主的沉积岩系,盆地边缘地区则发育有部分冲积扇及河流相沉积.铀矿体主要赋存于洛河组风成砂岩中,砾岩中也发育有少量矿体.本文在野外地质调查研究的基础上,通过薄片鉴定、扫描电镜及能谱分析和逐级化学提取实验等手段,开展岩石学特征、矿物共生组合及铀赋存状态的初步研究.结果表明,铀矿物大多为沥青铀矿,其共伴生矿物以新生组分锐钛矿、黄铁矿、磷灰石、粘土矿物为主,也有少量铀矿物赋存于石英长石等原生颗粒的边缘或裂隙中.逐级化学提取实验分析显示,彭阳铀矿床中铀的赋存状态主要为碳酸盐态、残渣态和有机质及硫化物结合态,其中以铀矿物形式赋存的铀含量平均约为四分之三,吸附态铀含量约为四分之一.上述研究为铀沉淀富集规律研究和地浸采矿应用提供基础资料.
