小兴安岭成矿带航放场特征

正航放是航空伽玛能谱测量(又称航空放射性测量)的简称,通过航放测量获取小兴安岭地区航放总计数率(TC)及K、U、Th含量的区域分布信息,通过系统校准换算得到的航放K、U、Th含量,可以反映三核素地表含量的分布和变化特征,它们与地表岩性、地形、地貌形态等直接相关,不同地貌形态、不同构造单元和不同岩性其放射性元素含量、航放总计数率具有明显差异。1 K、U、Th含量统计分析为了解K、U、Th含量的分布特点,分别对区     

龙门山地区磷矿开采和加工过程中放射性环境问题探讨

磷矿开发利用在促进了工农业的发展同时,与之伴随的环境污染问题日趋突出。由于大多数磷矿都伴有高含量的放射性铀、钍等元素,通过加工,会转移至磷肥及副产品中,通过施肥、淋滤、风化、氧化等作用进入环境中,不仅会导致土壤环境中放射性元素含量增加,而且可以通过食物链转移至人体,导致公众内照射剂量增加。     

北秦岭陕西华阳川地区铀矿物质来源

华阳川铀矿床位于老牛山岩体与华山岩体夹持部位,矿体严格受控于NW—SE向华阳川脆韧性剪切带,赋矿岩石以石英碳酸岩为主,伟晶岩次之。关于华阳川铀矿床的物质来源一直没有较可信的研究成果。系统收集航放、地质、钻探、选冶试验等资料,采用地表放射性物探、地质、锆石U-Pb定年等手段,计算各地质体(单元)的放射性能谱特征、年龄特征,研究岩体、脉岩的构造展布规律和放射性元素的迁移规律,揭示华阳川铀矿的成矿物质来源。地表伽玛能谱特征显示,华山岩体翁峪花岗岩U含量为4.82×10^-6～6.46×10^-6,Th含量为23.03×10^-6～31.08×10^-6,Th/U值为5.29～6.00;老牛山岩体主要岩石单元U含量为9.27×10^-6～11.18×10^-6,Th含量为24.39×10^-6～27.72×10^-6,Th/U值为2.64～3.55,两者均具有高铀、高钍的特征;地球化学特征显示,华山岩体与老牛山岩体均具有埃达克质岩的特征...     

浙西石煤产区放射性污染及防治对策

浙江西部山区石煤资源丰富，广泛地被应用于石煤制品的生产和用做部分电厂、山区农村的燃料。石煤中U、Th等放射性核素含量高，致使部分石煤及其制品中U、Th等放射性核素含量偏高。U、Th是Rn的母体元素，衰变后不断释放出氡气，导致石煤产区居室内氡浓度和居民年辐射剂量当量严重超标，危害人体健康。本文在分析该区部分石煤产区、石煤制品、石煤电厂以及居室中的放射性元素污染的基础上，提出了相应的防治措施。     

在非放射性矿产开发中天然放射性核素对人类（活动程度）影响的评价

本文探讨了从防护和生态学观点最为重要的放射性元素及其衰变子体产物的存在形式和迁移能力，因为在非放射性矿产的开采和加工过程中以及在进行以工程为目的山地工作中，它们可能会积累。将岩石的工业产品、废物和废石堆根据其对职工的危险程度进行了分类，同时拟定了避免对生物圈造成污染的技术措施。     

安徽省岩浆岩放射性生热率特征研究

安徽省位于中国东南部,岩浆活动频繁,燕山期岩浆活动最为发育,岩浆岩出露面积超过13 000 km~2,不同类型、不同成因的岩石均有发育,并以大别山、长江中下游和皖南地区较为集中。本研究在安徽省不同岩浆岩带共采集159块样品开展岩石密度和放射性生热元素含量测试,结合前人对安徽省岩浆岩放射性生热元素的测试结果,首次对安徽省岩浆岩开展了系统的放射性生热元素统计研究。结果表明：安徽省岩浆岩总体上U、Th、K平均含量相差较大,花岗质岩石及中酸性火山岩的U、Th、K含量较高,基性岩浆岩的U、Th、K含量较低;不同类型的岩浆岩放射性生热率相差较大,花岗质岩石和中酸性火山岩生热率相对较高且变化范围较宽,基性岩浆岩生热率较低且变化范围较窄;金寨和长江中下游地区部分花岗岩生热率超过5μW/m~3,为高产热花岗岩;岩浆岩的热贡献主要来自于U和Th的放射性衰变热,K的衰变热贡献相对较低,一般不超过10%。通过本文研究,结合前人对安徽省地质地热等方面的研究成果,发现岩浆岩放射性生热对安徽省温泉分布、干热岩勘探和U矿床勘探等具有重要的意义,可为安徽省后续地热资源勘查开发研究提供支撑。     

岩石古放射性生热率的校正及其地球化学意义

岩石放射性生热率是研究油气沉积盆地地热及花岗岩体热演化史的一个重要参数,但由现今采样分析所测得的放射性元素含量计算得出的是当今的放射性生热率。因此,本文根据辐射衰变定律及U、Th和K的放射性生热参数,导出三种不同计量单位(μWm-3,μJg-1a-1,HGU)校正岩石古放射性生热率的公式。它们可应用于沉积盆地中古地层放射性生热率的计算和校正,也适用于铀矿床成矿古水热系统热源及花岗岩体热演化史的研究。     

引绰济辽工程文得根引水隧洞放射性调查评价

对长约70 km引水工程洞线上进行的地面伽马能谱测量、陆地伽马剂量率测量、土壤氡浓度测量、岩石表面氡析出率测量以及钻孔岩芯样品的放射性元素U、Ra、Th、K含量分析的综合放射性地质调查,并对获得的测量数据进行分析研究。结果表明,测区引水沿线地质体放射性核素当量含量平均值为：U 1.56×10-6,Th 14.12×10-6,K 2.16×10-2;钻孔岩芯放射性元素分析含量平均值为：U 32.34 Bq/kg,Ra 35.68 Bq/kg,Th 35.29 Bq/kg,K 865.65 Bq/kg。陆地伽马剂量率为90.42 nGy/h;土壤氡浓度平均值为4 272.1 Bq/m3;岩石表面析出率平均值为4.01×10-2 Bq/m2·s。根据测量结果,利用内照射和外照射辐射剂量计算了对施工人员造成的辐照剂量为0.759 mSv,低于国家对公众的剂量限值1 mSv/a,表明引水工程输水隧洞的施工在安全辐射范围内。     

运用1∶25万化探数据进行区域天然放射性填图评价

以1∶25万化探数据为切入点,在分析全国各城市天然放射性水平特征的基础上,运用放射性填图评价技术研究了成都平原天然放射性水平分布特征。结果表明:研究区环境天然放射性核素238 U、232 Th、40 K含量频数均呈正态分布,数值均在正常本底范围内;238 U比活度总体上低于全国平均水平,232 Th和40 K比活度总体上高于全国平均水平;研究区天然放射性辐射水平、γ射线照射量率、吸收剂量率、年有效剂量当量均低于世界和全国的平均水平;研究区γ射线内、外照射指数均在国家限量标准控制范围之内。     

航空伽马能谱测量在浅覆盖区 地质填图单元划分中的应用

不同岩性的岩石,其放射性元素U、Th和K的含量不同,即使是同一岩性的岩石,由于成因不同,形成年代不同,地质演化过程不同,其放射性元素含量也不同.笔者根据放射性元素在岩石中分布的这个特点,利用航空伽马能谱测量数据,采用多元统计分析方法,对航空伽马能谱测量数据进行分析,并作出动态聚类图,然后再与已有的地质图对比,分析各种岩性放射性元素U、Th和K的含量,为该地区进行下一步地质工作提供依据.     

A comparative study of uranium–thorium accumulation at the western edge of the Arabian Peninsula and mineral deposits worldwide

Jordan, located at the western edge of the Arabian Plate, stands out from the remaining part of the Arabian Peninsula by its abundance in radioactive elements, mainly uranium, in a way so far not found elsewhere on the Arabian Peninsula. Uranium (U) and thorium in Jordan are concentrated in eight different types of ore mineralization: (1) intrusive-related (intramagmatic), (2) vein-type, (3) superficial, (4) sandstone-hosted (5) limestone-hosted, (6) U-Th-REE placer-type, (7) black shales, and (8) phosphorites. The major concentration of radioactive elements are synsedimentary and diagenetic in nature, mainly in near-shore marine depositional environments where uranium contents are abnormally high in the late Cretaceous to Paleogene phosphorites and increasing towards the mobile shelf of the Tethys ocean. These uraniferous phosphorites form the source of uranium that was redeposited within terrigenous chemical residues of lacustrine-fluvial depositional systems in Central Jordan (calcretes). Faultbound radiometric anomalies are caused by hot brines being vented along with the Jordan-Dead-Sea rifting. Presumably, low-grade U accumulation in (hot) black shales and marls of Silurian age are responsible for these radiometric anomalies. In the present paper, the Jordanian uranium concentrations are compared with reference types of uranium deposits elsewhere in the world to get an idea if the geological, chemical, and mineralogical features of analogue uranium mineralization in Jordan are indicative of economic targets. The uranium concentration in Jordanian phosphorites has been tracked beyond the border into Syria, Iraq, Israel, and Saudi Arabia. The uranium potential in neighboring countries is assessed based on the current geological data available for the Mediterranean Phosphorite Belt which is poised to become a another string to the bow with respect to energy supply on the Arabian Peninsula.     

含矿自流盆地的放射性环境地质和地浸法开采铀矿床

层间 渗入型铀矿床不同的现代水文地质环境对采用地浸方法采矿过程中保护环境不受污染的程度不同。根据水文地质特征 ,特别是水动力指标可将铀矿床分为有利的、不利的和非常不利的 3类 :有利的铀矿床指矿区的水流从矿带两侧分别从氧化带和原生灰色岩石带以斜交形式向矿带方向流动 ,并沿矿带走向方向相互作用。这样的水文地质条件下工艺溶液不可能流到矿带范围以外 ,故环境将不受污染。完全不利的水文地质条件是指水流垂直穿透矿带从氧化带向原生灰色岩石带流动 ,它们能将有毒元素和重金属带到矿带以外的相邻地区。不利的水文地质条件是指同时具有上述两种特征的铀矿床。实践证明 ,水文地质条件有利于地浸方法开采和有关工艺流程时 ,开采工作对现场造成的污染要比天然放射性污染低。     

新疆与哈萨克斯坦和蒙古国磷块岩资源对比

新疆磷矿资源分布地区不多,探明储量也很少,且品位较低,但和新疆相邻的哈萨克斯坦和蒙古国磷矿资源十分丰富,合理开发利用与新疆相邻国家的境外资源,是实施矿业勘查开发“走出去”的重要步骤.     

秦岭华阳川地区航空伽马能谱异常特征及铀找矿方向

华阳川铀铌铅矿床是北秦岭造山带内一种类型特殊的铀多金属矿床。为了实现在外围快速找矿的目的,在矿床及其周边开展了1∶1万高精度航空磁放测量,获得高精度的航空放射性数据,通过对航放数据的解释,对下一步找矿勘探工作的部署有重要意义。通过对宏观上放射性元素的分布特征的研究,认为铀、钾异常分布特征相似,在测区西部有大面积分布,东部无成规模异常,钍异常在测区中部形成东西向异常带,与韧性剪切带的位置一致。铀异常有明显受北西向和北东向两组断裂控制,且在华阳川断裂北东盘异常面积大,强度高,但南西盘太古宙地层却无明显铀异常。本次研究计算了钍钾比、钍铀比、铀钾比、古铀含量、活性铀含量等参数,掌握了元素在不同地层单元的迁移富集规律。根据航空放射性异常,开展地面验证工作,圈定3条铀矿化带,达到了快速找矿的目的,对铀矿等战略性矿产的成矿规律研究及找矿勘查有积极意义。     

Natural analogues for the transuranic actinide elements: An investigation in Minas Gerais,Brazil

A highly weathered deposit of thorium and rare earth elements located near the summit of a hill in the state of Minas Gerais, Brazil, is being studied as an analogue for a radioactive waste repository that sometime in the distant future may be eroded to the surface or intruded by groundwater Thorium serves as an analogue for Pu⁴⁺, and La³⁺ as an analogue for Cm³⁺ and Am³⁺ The mobilization rate constants of the analogue elements by groundwater are so slow (of the order of 10⁻⁹ per year) as to suggest that essentially complete radioactive decay of the transuranic actinides would occur in place even under the relatively unfavorable conditions that exist at a site such as this     

应用能谱-扫描电镜和X射线衍射技术研究原煤伴生矿物中稀土和放射性元素赋存形式

研究原煤中稀土及放射性元素的赋存形式,对原煤是集中还是分散利用、燃煤过程中粉煤灰的排放截留、从原煤或粉煤灰中提取稀土及放射性元素等方面都具有指导意义。由前人研究可知不同矿区原煤中稀土及放射性元素的赋存形式有差异。本文研究了山西省霍西煤田两个矿区175个煤样中稀土及放射性元素的赋存形式,应用背散射电子图像(BSEI)定位分析区域,应用BSEI、能谱-扫描电镜法(EDX-SEM)中的面分析(EDS-mapping)和粉晶X射线衍射法确定了主要伴生矿物,应用BSEI和EDX-SEM中的点分析(EDS-point)确定了微量伴生矿物。在煤样中发现了铈镧钕钇镝钪六种稀土元素及一种放射性元素钍,其中铈、镧和钕主要以磷酸盐形式伴生于高岭石类矿物中,部分伴生在含氧化铝或氧化硅较多的矿物中,少量存在于碳中;钇、镝以磷酸盐或氧化物形式独立存在于碳中;在部分锆石、独居石中分别发现了钪和钍。研究表明,该矿区煤样中稀土元素主要以细粒自生矿物的形式伴生在其他矿物中,少数以独立矿物的形式存在于碳中,放射性元素钍伴生在独居石中。     

Trace element mobility in mine waters from granitic pegmatite U–Th–REE deposits,Bancroft area,Ontario

Small, low-grade, granitic pegmatite U–Th–REE deposits are found throughout the Grenville geological province of eastern Canada. Groundwater quality at historical mining properties in the Bancroft area was investigated in order to better understand the mobility of trace elements that may pose health risks if there is renewed development of this class of mineral deposit. Groundwater samples were obtained from diamond drill holes, flowing adits and flooded mine shafts. Uranium occurs almost entirely in the dissolved (<0.45 μm) phase and is found at concentrations reaching 2579 μg/L. The Canadian maximum acceptable concentration for U in drinking water (0.02 mg/L) was exceeded in 70% of samples. Regulatory limits for ²²⁶Ra (0.5 Bq/L) and for ²¹⁰Pb (0.2 Bq/L) were generally exceeded in these samples as well. Speciation modeling indicates that over 98% of dissolved U is in the form of highly mobile uranyl-Ca–carbonate complexes known to inhibit U adsorption. Uranium concentrations in groundwater appear to be correlated with the uranothorite content of the deposits rather than with their U grade. Uranothorite may be more soluble than uraninite, the other ore mineral, because of its non-ideal composition and metamict structure. Thorium, released concomitantly with U during the dissolution of uranothorite and thorian uraninite, exhibits median and maximum total concentrations of only 0.1 and 11 μg/L, respectively. Mass balance and stoichiometric considerations indicate that almost all Th is immobilized very close to its source. The sums of total light REE (La–Gd) concentrations have median and maximum values of 6 and 117 μg/L, respectively. The sums of total heavy REE (Tb–Lu) concentrations have median and maximum values of 0.8 and 21 μg/L, respectively. Light REE are derived mainly from the dissolution of metamict allanite whereas the sources of heavy REE are widely dispersed among accessory minerals. Fractionation patterns of REE in the dissolved phase are flat or concave, with negative Ce anomalies associated with more oxic groundwaters. The data suggest preferential LREE and HREE complexation with organic and carbonate ligands in the dissolved phase, respectively. Fractionation patterns in the suspended particulate phase exhibit decreasing enrichment with atomic number from La to Gd and a flat profile from Tb to Lu. This is explained by preferential sorption of LREE and uniform sorption of HREE. Manganese particulates are the most likely sorbents. Potential health risks from Th or REE in mine waters are unlikely due to the very low mobility of these elements. Uranium, on the other hand, exhibits high mobility in shallow, oxic groundwaters and drainage from some mine adits may require mitigation.     

Uranium and Thorium in Phosphatic Bone Debris from the Ocean Bottom

Uranium and thorium content, as well as their distribution patterns are studied in biogenic phosphates from the Atlantic and Indian oceans. The material studied is represented by differently lithified fish remains (bones, scales, teeth) and marine mammal bones (ribs, vertebras, earbones) collected from both reduced shelf sediments and oxidized pelagic ones. The U content in the material varies from 0.7 to 700 ppm, and the Th content ranges from less than 0.5 to 14 ppm. The U/Th ratio varies from 0.16 to 400. Contents of both elements increase with the lithification of biogenic phosphates. The U concentration is more intense on shelves, whereas the thorium concentration increases in pelagic areas. A partial positive correlation of U and Th with Fe but a negative correlation of U with organic carbon are noted. The latter corresponds to increasing lithification of biogenic phosphates. Calcium phosphate, which is transformed from hydroxyapatite to fluorcarbonate-apatite serves as the main carrier of U, while transformed organic matter is a minor agent. Thorium is mainly bound with Fe.     

3112矿床深部矿体偏镭的放射性同位素研究

应用铀、钍、锕铀系中~(228)Ra、~(230)Th、~(231)Pa、~(232)Th等同位素与~(38)U、~(226)Ra之间存在量关系探索了3112矿床深部矿体偏镭的原因。结果表明该矿床深部偏镭是外来镭后期叠加所致。分析数据显示,严重的偏镭现象难以用局部偏铀地段的镭流失予以补偿。这就提示有隐伏镭源体铀存在的可能性。本文所述方法也适用于地表放射性异常性质的判别研究。