福建煤系石墨资源状况和开发前景

福建省煤系石墨赋存于中二叠统童子岩组,是无烟煤受高温高压作用进一步变质而成,属隐晶质石墨。通过调查发现,福建省煤系石墨矿井、勘查区处于未开采或停采状态,开采矿区也多以煤炭开采的形式生产销售,造成资源浪费。为合理开发利用煤系石墨资源,采用d₀₀₂（碳层间距）-R₂（拉曼参数）模板鉴别煤系石墨并确定煤系石墨等级,结合区域构造的控制作用,划分了大田-漳平与永安-安溪石墨成矿区。在此基础上,综合实测数据和历年勘查资料分析,预测出永安长垇、永安下盖竹-甫弼-塘下洋、大田琼口-小溪洋-永安老鹰山、漳平可坑-乌石隔、漳平乌坑-华安福田5块煤系石墨资源远景区,其预测资源量8 196万t,展现了良好的开发前景。针对目前煤系石墨资源开发利用现状,提出“规范煤系石墨资源开采秩序、建立煤与煤系石墨鉴别指标并设立明确的煤矿与石墨矿权规范、优化石墨资源开发利用体系等”系列建议,以实现福建石墨产业结构协调化、技术高度化、产品系列化和价值链完整化。移动阅读     

Sedimentary processes controlling ultralong cells of littoral transport: Placer formation and termination of the Orange sand highway in southern Angola

This study focuses on the causes, modalities and obstacles of sediment transfer in the longest cell of littoral sand drift documented on Earth so far. Sand derived from the Orange River is dragged by swell waves and persistent southerly winds to accumulate in four successive dunefields in coastal Namibia to Angola. All four dunefields are terminated by river valleys, where aeolian sand is flushed back to the ocean; and yet sediment transport continues at sea, tracing an 1800 km long submarine sand highway. Sand drift would extend northward to beyond the Congo if the shelf did not become progressively narrower in southern Angola, where drifting sand is funnelled towards oceanic depths via canyon heads connected to river mouths. Garnet–magnetite placers are widespread along this coastal stretch, indicating systematic loss of the low‐density feldspatho‐quartzose fraction to the deep ocean. More than half of Moçamedes Desert sand is derived from the Orange River, and the rest in similar proportions from the Cunene River and from the Swakop and other rivers draining the Damara Orogen in Namibia. The Orange fingerprint, characterized by basaltic rock fragments, clinopyroxene grains and bimodal zircon‐age spectra with peaks at ca 0·5 Ga and ca 1·0 Ga, is lost abruptly at Namibe, and beach sands further north have abundant feldspar, amphibole‐epidote suites and unimodal zircon‐age spectra with a peak at ca 2·0 Ga, documenting local provenance from Palaeoproterozoic basement. Along with this oblique‐rifted continental margin, beach placers are dominated by Fe–Ti–Cr oxides with more monazite than garnet and thus have a geochemical signature sharply different from beach placers found all the way along the Orange littoral cell. High‐resolution mineralogical studies allow us to trace sediment dispersal over distances of thousands of kilometres, providing essential information for the correct reconstruction of ‘source to sink’ relationships in hydrocarbon exploration and to predict the long‐term impact of man‐made infrastructures on coastal sediment budgets.     

天然金珍珠和染色金珍珠的致色因素和鉴定分析方法研究进展

金属离子、卟啉和类胡萝卜素是天然金珍珠的主要致色成分,有机染料是染色金珍珠的致色成分。鉴定天然金珍珠和染色金珍珠的主要手段有常规观察检测、紫外可见吸收光谱法、拉曼光谱法、荧光光谱等。本文结合天然金珍珠的致色成分和染色金珍珠的染色方法,对两类金珍珠的鉴定技术作了评述,认为常规观察检测是十分必要的,染色珍珠颜色分布不均匀,在孔眼内或表面破损处可看到染料的沉淀浓集;紫外可见吸收光谱法是目前较为常用的鉴定方法,天然金珍珠主要吸收峰位于350~360 nm,而染色金珍珠则出现明显的410~450 nm谱峰;应用拉曼光谱法鉴定可获得天然金珍珠在275 cm-1明显的特征峰,而染色金珍珠出现强的荧光背景峰;应用荧光光谱法鉴定金黄色天然珍珠在376 nm处光激发时谱峰是以472 nm为中心,而染色珍珠在372 nm处受光激发时谱峰位于436 nm。这些鉴定方法仍然在实验验证阶段,进一步优化和开发新的测试手段则是今后重要的发展方向。     

湖南锡田钨锡多金属矿床流体包裹体研究

锡田钨锡多金属矿床是南岭钨锡成矿带的重要组成部分。文章主要针对石英脉型钨锡矿和云英岩型钨矿中的石英流体包裹体进行了显微测温和激光拉曼光谱分析,流体包裹体分为4类:富液相两相水溶液包裹体(L型)、富气相两相水溶液包裹体(V型)、V_(CO_2)-L_(CO_2)-L_(H_2O)三相包裹体(C型)和含子晶三相包裹体(S型)。石英脉型钨锡矿均一温度为240~440℃,ω(NaCl_(eq))为1.4%~9.5%,云英岩型钨矿均一温度为370~470℃,且富锡石样品均一温度(t_h:310~420℃,ω(NaCl_(eq))为4.3%~9.5%)略高于富黑钨矿样品(t_h:240~340℃,ω(NaCl_(eq))为1.4%~7.7%)。流体包裹体气相成分主要为CO_2、CH_4、N_2。结合流体包裹体显微测温、激光拉曼光谱分析结果和野外矿床地质特征,探讨了成矿流体中N_2、CH_4的源区、W和Sn的赋存状态以及其成矿机制。W以一系列钨酸、钨酸根离子、碱金属钨酸盐赋存于流体中,Sn主要赋存状态为Sn(+2价)-Cl络合物。石英脉型钨锡矿因流体上升至花岗岩体或围岩的构造裂隙中,成矿流体与围岩相互反应以及与地壳流体与大气水混合,其p、t急剧下降以及流体pH值变化,导致黑钨矿沉淀,成矿流体从还原环境转为氧化环境致使锡石沉淀成矿。云英岩型钨矿有效成矿机制是流体沸腾或不混溶。     

The parent material of Sydney laterites

The petrography of laterites in the Sydney district shows that source rocks range from shales—in which quartz grains are not common and average about 0.03 mm in diameter—to sandstones, with generally abundant quartz grains which may average up to 0.5 mm in diameter. Ferricretes or iron‐cemented duricrusts occur in rocks with coarser quartz grains, such as the Tertiary river gravels of the Maroota area. The porosity and permeability of these rocks have considerably influenced the nature and profiles of the laterites. Two possible sources of sesquioxides in the laterites appear to be the Wianamatta Shale and, perhaps more importantly, basic igneous rocks.     

河南嵩县七亩地沟金矿床成矿流体来源及演化——来自矿床地质和流体包裹体的证据

河南省嵩县七亩地沟金矿床位于华北克拉通南缘的熊耳山地区。矿床赋存在中元古代熊耳群中酸性火山岩中,矿体严格受构造断裂带控制,主要呈脉状产出,矿石以石英脉型占主导,少量蚀变岩型;主要矿石矿物为黄铁矿、少量方铅矿、闪锌矿、黄铜矿等。围岩蚀变以硅化、绢云母化、绿泥石化和碳酸盐化为主。成矿过程从早到晚可分为3个阶段:石英-黄铁矿阶段、黄铁矿-石英-多金属硫化物阶段和石英-方解石阶段。不同成矿阶段的石英和/或方解石中广泛发育流体包裹体。早阶段和中阶段石英中CO_2型流体包裹体、NaCl-H_2O型流体包裹体、含子矿物流体包裹体均有发育,晚阶段方解石中主要发育NaCl-H_2O型流体包裹体。从早阶段到晚阶段,流体包裹体均一温度分别为254~397℃、221~397℃、162~237℃,盐度w(NaCleq)从早阶段的3.52%~21.88%和34.95%~45.33%双峰值,经中阶段的0.42%~13.83%和29.11%~42.48%双峰值,到晚阶段w(NaCleq)为0.35%~5.86%。CO_2型包裹体估算的早阶段和中阶段捕获压力为93~199 MPa和47~169 MPa,晚阶段NaCl-H_2O型包裹体估算的捕获压力为28~64 MPa,相应的成矿深度为3.4~7.2 km、1.7~6.2 km和2.9~6.5 km,指示成矿发生在地壳隆升过程中,区域应力场由挤压向伸展转变。流体沸腾作用是导致硫化物和金等成矿物质快速沉淀的主要机制,通过沸腾和大气降水的混合,成矿流体系统由富CO_2向贫CO_2流体演化,由变质流体向大气降水演化。     

Raman spectroscopy, vibrational analysis, and heating of buergerite tourmaline

Polarized Raman spectra were collected for single crystal buergerite (NaFe₃Al₆(BO₃)₃Si₆O₁₈(O_0.92(OH)_0.08)₃F) from room temperature to near 1,375°C. Vibrational assignments to features in the room temperature spectra were determined by lattice dynamics calculations, where internal BO₃ motions dominate modes near 1,300 cm⁻¹, internal SiO₄ displacements dominate modes between 900 and 1,200 cm⁻¹, while less localized displacements within the isolated Si₆O₁₈ ring mix with motions within Na, Fe, Al, F, and BO₃ environments for fundamental modes below 780 cm⁻¹. At elevated temperatures, most buergerite Raman features broaden and shift to lower frequencies up to 900°C. Above this temperature, the lattice mode peaks evolve into broad bands, while OH stretch modes near 3,550 cm⁻¹ disappear. According to Raman spectroscopy, X-ray diffraction, differential thermal analysis, and scanning electron microscopy, buergerite undergoes a complex transition that starts near 700°C and extends over a 310°C interval, where initially, Al and Fe probably become disordered within the Y- and Z-sites, and most F and all OH are later liberated. A reversible crystal-to-amorphous transition is seen by Raman for buergerite fragments heated as high as 930°C. Buergerite becomes permanently altered when heated to temperatures greater than 930°C; after cooling to room temperature, these altered fragments are comprised of mullite and Fe-oxide crystals suspended in an amorphous borosilicate matrix.     

黑色合成碳硅石在群镶钻石首饰中的鉴定特征

近期,在珠宝市场上的一件＂黑白钻＂首饰中发现混有黑色合成碳硅石,该情况应引起国内外各珠宝检测机构的足够重视。采用宝石显微镜、红外光谱仪和拉曼光谱仪等测试方法对黑色合成碳硅石样品做了较详细测试与分析。结果显示,放大检查可见黑色合成碳硅石的表面粗糙,棱角圆钝,并伴有各种生长缺陷,部分可见残留的单晶硅;黑色合成碳硅石的红外反射光谱非常特征,且其拉曼散射光谱也缺失钻石位于1 332cm-1处的特征峰,可与黑色钻石相区别。     

内蒙古柳坝沟金矿床流体包裹体研究

对柳坝沟金矿床的包裹体进行系统的岩相学、显微测温和激光拉曼光谱研究,结果表明:包裹体的主要类型有富液包裹体、富气包裹体、CO2-H2O和含子矿物多相包裹体。流体包裹体液相成分为水,气相成分主要为CO2及H2O,并含有少量或微量的N2、H2S、CH4等挥发份。成矿流体属中高温、中低盐度、中等密度的NaCl-H2O-CO2体系。矿床形成于中深成矿环境。矿床的成矿作用是一个温度退缩和盐度降低的过程,成矿过程中发生过多次流体沸腾作用,流体的沸腾和CO2流体在Au成矿过程中发挥着重要作用。     

红外光谱-拉曼光谱无损检测技术对透闪石和阳起石鉴定特征的研究

透闪石属于角闪石族矿物,与阳起石构成完全类质同象,有关透闪石和阳起石的红外光谱和拉曼光谱的特征差异还未见有报道。本文以外观特征相似的5件广西大化黑青色阳起石样品和2件新疆塔县青玉样品为研究对象,在前期矿物成分测试的基础下,采用红外光谱和拉曼光谱进行测试和对比分析。结果表明,阳起石的红外光谱和拉曼光谱都表现为闪石类矿物的特征峰,与透闪石的特征峰存在细微差异,漫反射红外光谱的差异特征是鉴别两者最准确、快速、无损的依据,并且适用于任意形状的样品,符合珠宝玉石饰品实验室检测领域的要求,可为和田玉的分类分级和产地鉴别等提供科学依据。按照GB/T 16552-2017与GB/T 16553-2017规定,广西大化黑青色阳起石可定名为和田玉。