赣南隆坪萤石矿床成矿时代及成因初探:来自萤石Sm-Nd测年及黑云母电子探针的证据

隆坪萤石矿床是赣南已探明的大型单一萤石矿床,矿体产于永丰复式岩体外接触带北东向硅化破碎带中。文章首次 采用Sm-Nd等时线法对隆坪萤石矿进行测年和稀土元素分析,并对永丰复式岩体中黑云母矿物成分进行了系统的测试;获 得了隆坪萤石矿的成矿年龄为158±3 Ma,与永丰复式岩体的成岩时代基本一致,表明该矿床萤石成矿作用与晚侏罗世岩浆 活动关系密切。隆坪萤石矿中萤石轻稀土元素略富集,重稀土相对平坦,具微弱Ce正异常（δCe=1.08~1.11,平均1.09） 和 微弱Eu负异常（δEu=0.91~0.98,平均0.95）,指示了萤石矿床的成矿流体经历了相对较高的温度。黑云母电子探针分析结 果证实永丰复式岩体形成于相对高温、低压和高氧逸度的环境,岩浆起源于古老地壳物质的部分熔融,岩浆结晶分异晚阶 段岩浆期后热液富含F等挥发分。隆坪萤石矿床形成于晚侏罗世,成因类型为岩浆期后热液充填型。     

柴里煤矿二水平岩巷的工程地质问题探讨

论证了柴里矿区现代地应力场为大地静力场型，指出地应力研究的工程意义，通过层位，实践，经济效益几方面的对比，指出三灰是二水平主干岩层位选择的最佳层位。     

煤层气井钻井液特点的探讨

煤层气参数井一般要求采用清水钻取煤心，生产井则主要采用无粘土钻井液、优质钻井液或清水施工。应用清水或无粘土钻井液钻井时，孔内产生的岩屑或岩粉进入煤储层后，会堵塞煤层裂隙或孔隙，降低煤层气产能。而应用优质钻井液钻进时，由于泥皮的过滤作用，能更好地保护煤层不受伤害，同时能降低钻井施工风险，确保井内安全。     

应用电子探针技术研究桂西南下雷锰矿床锰钾矿的结构特征

八面体分子筛(OMS-2)具有2×2孔道结构,在离子交换、催化剂、能源和环境等方面具有非常重要的应用价值,然而天然OMS-2矿物材料——锰钾矿在典型结构的成分精细表征和成因研究等方面仍然缺乏.环带和核-边结构在锰氧化物矿物的结构中非常具有代表性,明确其矿物种属、探索其成分特征对于探究其成因、开拓锰氧化物的应用具有重要意...     

电子探针技术测定稀有多金属矿中微量元素硅钽钨的实验条件设定

近年来对稀有多金属矿的研究越来越趋向于微区化、微量化,作为其重要研究手段之一,电子探针定量分析在微量元素测试方面取得很大的进展.在微量测试过程中,除了增大测试束流,提高测试时间来降低检出限以外,更要注意去除来自其他元素,特别是主量元素的干扰.在日常测试稀有多金属样品的过程中,S i、Ta、W三个元素存在相互干扰,这种干...     

Fingered Intrusion of Shallow Saucer-shaped Igneous Sills: Insights from the Jiaojiang Sag, East China Sea

An extensive suite of igneous sills was intruded into the Tertiary sedimentary section of the Jiaojiang sag,East China Sea.This suite has been well imaged offshore through 2D and 3D seismic surveys,showing a close relationship with CO2 content in nearby gas discoveries.A new observational model,which incorporates simple upward propagation,simple horizontal propagation,and transgressive propagation,was proposed to interpret these sill intrusions.In this model,the source magma of the saucer-shaped sills was injected from their lowest points near the center.The transgressive propagation can be interpreted as a combination of the vertical and horizontal propagation.Most shallow sub-volcanic intrusions in the Jiaojiang sag exhibit fingered characteristics,both vertically and horizontally.The vertical fingered propagation produced saucer-shaped sills arranged in the flower style.Along the brims of lower sills could usually be found the upper sills,which are interpreted to have formed simultaneously with or later than the lower feeder sills.In the second type,the chilled paths of the older sills were reutilized by subsequent intrusions.The horizontal fingered propagation formed sheet intrusions that exhibit groove,lobate,tubular,and crevasse splaylike geometry in plan view.In 3D view,the sheet intrusions have still preserved the lower center and higher rim that similar with the sub-rounded saucer-shaped sills.Although fracture propagation may be important,flow inflation was the key mechanism of magma intrusion.Further consideration of the mechanisms underlying sill formation may help explain the fingered characteristics of sill propagation.     

内蒙古北山老硐沟金矿石榴子石地球化学特征

老硐沟金矿是北山成矿带东段发现的中型金矿床,是多期次多阶段成矿作用叠加的产物,矿床成因类型复杂。矿床共分为5个矿段,其中Ⅲ矿段以矽卡岩矿体为主。矽卡岩矿物以石榴子石为主,可分为早、晚两期,早期石榴子石更具震荡环带。通过详细的镜下观察和电子探针对两期石榴子石进行了系统研究,早期石榴子石核部以钙铝榴石组分为主,向边部为钙铁−钙铝过渡组分;晚期石榴子石以钙铁榴石为主。石榴子石化学成分特征表明,早期矽卡岩化阶段,热液环境为中酸性、弱氧化—弱还原环境;后期铁质含量增多,氧逸度增加,热液环境碱性、氧化性增强。老硐沟金矿Ⅲ矿段石榴子石为钙铁−钙铝榴石系列,属热液交代成因,早期多形成钙铝−钙铁榴石,伴随铜矿化,晚期热液环境变化,钙铁榴石增多,黄铁矿化、毒砂矿化增多,造成金富集成矿。     

北大别黄土岭麻粒岩锆石U—Pb离子探针定年

阴极发光显微结构分析表明 ,北大别黄土岭麻粒岩中存在三种类型的锆石 :原岩锆石、麻粒岩相锆石和残留锆石。对它们分别进行离子探针定年 ,得到黄土岭麻粒岩的原岩年龄约为 2 70 0 Ma、麻粒岩相变质事件的年龄为 2 0 5 2± 10 0 Ma、残留锆石的年龄为约 3.4 Ga。以上研究表明黄土岭麻粒岩为残存的扬子板块的结晶基底 ,而约 3.4 Ga残留锆石的发现 ,则首次证明大别山地区存在古太古代的陆壳物质     

Near–surface ground temperature regime variability in selected microenvironments, Kärkevagge, Swedish Lapland

The importance of topographic microvariability in influencing shallow (10–50 cm depths) soil temperature regimes in arctic–alpine Kärkevagge, northern Sweden, from August 1999 to July 2000 is demonstrated using six sites. The ground microclimate on the tops of very large boulders forming an extensive boulder field in the central valley bottom is more comparable to that at an alpine ridge–crest site 300 m higher than it is to the microclimate at the base of one of the boulders. The boulder crests also differ substantially from the more generalized valley–bottom conditions outside the boulder field. Assuming that chemical processes may be active at temperatures at or above 0°C, sites in the valley experience favorable conditions from 159 to 324 days of the year. Aside from the annual cycle, freeze–thaw cycles are infrequent within Kärkevagge.