牙克石市翠干公路岭上铅锌钼多金属矿床地质特征简述

该矿床位于阿尔山—博克图—鄂伦春成矿带的中南部,产于晚侏罗世玛尼吐组之中,矿体受北西向次级构造控制,成因类型为斑岩型及破碎带蚀变岩型。     

大兴安岭南段多金属成矿带硫、铅同位素组成及其地质意义

大兴安岭南段是我国北方重要的多金属矿床成矿带,对其成矿物质来源的分析研究有利于区域成矿规律的总结。在前人的工作基础上,对典型矿床的矿石矿物进行了硫、铅同位素研究。结果表明:闪锌矿、方铅矿、毒砂、黄铜矿、辉钼矿等硫化物的δ34S值主要变化范围为-6‰～4‰,平均值为0‰,峰值出现在0‰～2‰,呈塔式分布;无明显的重硫、轻硫富集,说明硫源较单一;矿石矿物及岩石的206 Pb/204 Pb、207Pb/204Pb、208Pb/204Pb值的变化范围主要集中在18.13～18.74、15.38～15.68和37.1～38.93,其平均值分别为18.38、15.54和38.09。同时,数据结果显示:成矿带的东部与西部存在较为明显的铅同位素差异,西部矿床中铅的分布主要集中在造山带演化线附近,而东部矿床中铅主要集中分布在上地幔和造山带演化曲线附近。     

精密弦矢导线法与边角导线法比较浅析

精密导线法分为边角导线法和弦矢导线法，是监测水库拱坝水平位移的重要方法。弦矢导线法是根据导线边工变和矢距变化的观测值来得坝体的实际变形量；边角导线法则是根据导线边长变化和导线的转折角观测值来计算坝体的变形量。比较分析了边角导线法和弦矢导线法的设计原理与设计方法，认为精密弦矢导线法与精密边角导线法相比具有如下优点：（1）复测简单，速度快，劳动强度小；（2）精密高且稳定，不受折光等外界条件影响；（3）便于采用数字化遥测，可为实现位移值计算自动化奠定良好基础。     

广西大厂锡多金属矿床S、Pb同位素组成对成矿物质来源的示踪

为了查明广西大厂锡多金属矿床成矿物质来源,本文对不同类型、不同产状矿体的硫、铅同位素的组成进行分析和对比研究。结果表明：大厂不同类型或产状的矿体,其成矿物质来源是相同的;硫同位素特征显示,锌铜矿体为典型的岩浆硫来源,锡矿体为混合硫来源,硫同位素比值的变化与成矿过程和环境有关,反映深部来源成矿流体在由下向上的运移过程中,有围岩组分的加入。铅同位素特征表明,铅的来源主要为与岩浆作用有关的壳源铅,但也有上地壳及壳幔混合来源的铅参与     

离子选择电极法测定水热气体中的硼含量及硼的气态迁移能力研究

火山和成矿地质现象表明硼可以在含水流体和气体中运移,本文应用离子选择电极法测定水热气体中硼的溶解度,以揭示硼的气态迁移能力。使用氟硼酸盐选择电极,测定了经氟硼酸化的硼酸标准溶液和含硼气体凝结水的电位,当硼含量处于地质流体的主要范围内(0.52~524.50 mg/L)时,电极电位与硼浓度的对数呈现出灵敏度很高的能斯特线性关系,标准曲线具有很好的稳定性和重现性。本方法测定硼的检出限为0.13 mg/L,低于饮用水标准规定的硼含量限值,适用于测定水热气体中的硼含量。硼酸挥发实验显示,硼在150℃、0.37 MPa水蒸气中的含量可达0.65%~0.72%,与富硼火山喷气的硼含量相符,显示硼在高温水热条件下可在气相中显著迁移,且H_3BO_3气态分子是硼的主要迁移形式之一。矿床地质特征和实验表明,硼的气态迁移和电气石化与稀有金属型伟晶岩的形成和矿化以及某些热液-气成型Sn-W、Mo矿床和斑岩型Cu、Au矿床的形成密切相关。     

乌贼墨黑色素对铅中毒小鼠的排铅作用及其对体内钙、锌和铜含量的影响

本文研究了乌贼墨黑色素对铅中毒小鼠的排铅作用及对小鼠体内钙、锌和铜含量的影响。采用48只小鼠为实验对象,按体质量随机分为阴性对照组,醋酸铅模型对照组,乌贼墨黑色素低(50mg/kg)、中(100mg/kg)、高(200mg/kg)剂量组以及阳性对照组(1.5g/60 kg),除阴性对照组外其余各组均每天腹腔注射醋酸铅溶液(7mg/kg)10天。第11天起各剂量组用乌贼墨黑色素灌胃,阴性对照组及醋酸铅模型对照组灌胃去离子水,阳性对照组灌胃二巯基丁二酸(DMSA),连续进行28d。采用原子吸收分光光度法测定小鼠的血液、肝、肾及脑组织中的铅、钙、锌和铜的含量。研究发现乌贼墨黑色素高剂量组(200mg/kg)显著降低了血铅含量,下降28.15%;乌贼墨黑色素中剂量组(100mg/kg)显著降低了肝铅含量,下降15.89%。同时,乌贼墨黑色素高剂量组对铅中毒小鼠肝铜、肾锌以及脑锌的含量高于醋酸铅模型对照组(P0.05),而与阴性对照组相比无统计学差异(P0.05)。以上结果表明高剂量、中剂量乌贼墨黑色素对血铅与肝铅有一定的排铅作用,同时高剂量的乌贼墨黑色素对小鼠肝脏中的铜、肾脏中的锌以及脑中的锌有保护作用。     

发变电站防雷接地阻抗测量分析

防雷接地网作为发变电站交直流设备接地及防雷保护接地,对保障生产安全运行起着重要的作用。发变电站接地网的测量结果存在接地阻抗值超标、感性分量过大的问题。通过仿真计算和实测对接地网测试中的感性分量对比分析,结果表明:接地阻抗的感性分量随着电流引线与电压引线之间距离增大而减小,通常不会大于阻性分量。过大的感性分量是由测试引线互感引起。基于此,给出了剔除互感阻抗的测量与计算方法,为接地网阻值的科学测试提供理论依据。     

Vertical Variation of Lead Content in Sediment Collected from Man‐made Tamagawa Dam Lake in Akita Prefecture,Japan

Alternation layered lake sediment that had accumulated over a period of 22 years, from 1990 to 2012, was collected from the Tamagawa Dam Lake, which is located in the northeastern part of Akita Prefecture. The lake water is acidified (pH = 4.1) by the inflow of high‐acidic thermal water (pH = 1.2) from the Obuki Hot Spring, the main hot spring in the Tamagawa Hot Spring area. The vertical variations in Si, Al, Fe, Ti, and Pb contents of the sediment were determined by XRF, EPMA, and LA‐ICP‐MS in order to clarify the sedimentation processes of the lake sediment. The layers consisting of the sediment could be mostly classified into three types: dark brown, yellowish brown, and reddish layers. The contents of Si, Al, Fe, and Ti corresponded to the variation in color of each layer in the sample. Based on the Si, Al, and Fe contents in the sediment of Tamagawa Dam Lake, the sources of these elements were classified as detrital origin in dark brown and yellowish brown layers (Si, Al, and Ti) and chemical precipitate origin in reddish layers (Fe). Detrital components were derived from volcanic rocks in the watershed of Tamagawa Dam Lake. The variation of Pb content did not accord with the color of layers. The content of Pb in the sediment of Tamagawa Dam Lake ranges from 45 to 522 ppm. The vertical variation of Pb content in sediment corresponded to the temporal variation of Pb content in thermal water from the Obuki Hot Spring from 1990 to 2012. A large influence of hydrothermal activity of the Tamagawa Hot Spring on the vertical distribution of Pb was found during the active period of the Obuki Hot Spring, resulting in high Pb content within layers at 5–8 cm from the bottom of the sample. T‐Fe₂O₃‐rich reddish layers were also found in this range. Therefore, it is assumed that T‐Fe₂O₃ and Pb originated from Obuki Hot Spring and precipitated in Tamagawa Dam Lake. However, no correlation was found between T‐Fe₂O₃ and Pb contents for any of the dark brown, yellowish brown, and reddish layers. Some layers with high Pb content were also found to have high SiO₂ and Al₂O₃ contents. These findings indicate that there are several possibilities for the sedimentation process of Pb. The sedimentation of Pb as well as that of T‐Fe₂O₃ in Tamagawa Dam Lake provides a good example of the accumulation of elements by chemical precipitation away from the source of elements.     

陕西旬阳泗人沟铅锌矿床地质及S、Pb同位素地球化学特征

陕西旬阳泗人沟铅锌矿床位于南秦岭褶皱系之大羊山复向斜南翼,赋存在上志留统水洞沟组第二岩性段的粉砂质千枚岩中。矿体受控于层间破碎带和劈理带,呈层状、似层状、透镜状产出。矿石矿物以闪锌矿、方铅矿、黄铁矿、磁黄铁矿和黄铜矿为主;矿石结构主要为它形-半自形粒状集合体结构、交代结构和固溶体分离结构;矿石构造主要为块状、条带状、浸染状和细脉状。激光剥蚀多接收等离子体质谱原位S同位素组成分析结果显示,矿石硫化物的硫同位素组成比较稳定,样品的δ³⁴S值主要介于0.17‰~2.03‰之间,具有塔式分布特征,反映硫主要源于地幔和深部地壳,也有少量地层硫参与。9件矿石硫化物样品的²⁰⁶Pb/²⁰⁴Pb值为17.198~18.213,平均17.845;²⁰⁷Pb/²⁰⁴Pb值为15.564~15.627,平均15.610; ²⁰⁸Pb/²⁰⁴Pb值为37.982~38.471,平均38.206;反映铅同位素总体较稳定,变化范围较小,铅同位素主要源于上地壳,也有少量地幔铅参与。综合矿床地质、地球化学特征,认为泗人沟铅锌矿床成因类型属于后生热液充填交代型。     

U‐Pb zircon age for the Etheridge Group,Georgetown region,north Queensland: Implications for relationship with the Broken Hill and Mt Isa sequences*

The Einasleigh Metamorphics are the lowest exposed component of the Etheridge Group, part of the Etheridge Province, in the Georgetown region of north Queensland. Previous dating of granites has imposed a younger age limit of about 1550 Ma for the depositional age of the Etheridge Group. Based on SHRIMP U‐Pb analyses of zircon from mafic (1674.9 ±3.3 Ma and 1655.9 ±2.2 Ma) and felsic (1695.8 ± 1.5 Ma and 1684.2 ± 2.1 Ma) intrusive rocks in the Einasleigh Metamorphics, it can now be demonstrated that deposition commenced at about 1700 Ma, and continued for an estimated 100 million years. The stratabound, base‐metal deposits in the Mt Isa Inlier, Broken Hill Block and McArthur Basin formed in the early part of this time span, thereby suggesting potential for these styles of mineralisation in the Georgetown region.