正交设计和方差分析应用于悬浮物和沉积物的EDAX分析条件试验

本文用正交试验和方差分析对悬浮物和沉积物粉末样品的EDAX分析进行了条件试验和数据处理,找出影响试验结果的主要因素和最佳分析条件,提高了分析结果的准确性。     

长牡蛎死因初探

本文对广西北海市海涂养殖的长牡蛎大量死亡的原因作了研究。电镜检测结果表明，在其外套膜、肝脏和中肠组织已吸入与积累了大量的直径为０．１～１．１０μｍ的球状有机化合物，未见微生物病原体感染，故该市海涂长牡蛎大量死亡的原因是其体内积累了大量的球状有机污染物而严重中毒引起的。     

The role of sediments in the phosphorus cycle in Lake Lugano. II. Seasonal and spatial variability of microbiological processes at the sediment-water interface

P, Fe, Mn, and S species were analyzed in water samples from the sediment-water interface collected at four seasonally different times during the course of a year at two sampling sites in the southern basin of Lake Lugano (Lago di Lugano). The results reveal the strong influence of the biogeochemical processes in the sediment on the chemical composition of the lake water above. Consumption of oxygen and nitrate under oxic to microoxic conditions in the water column as well as sequential release of reduced manganese and iron under anoxic conditions was observed as a direct or indirect consequence of microbially mediated degradation of organic matter. The seasonal pattern observed for the release and the retainment of dissolved reduced iron and manganese correlates well with the one for dissolved phosphate. Iron, manganese and phosphorus cycling are coupled tightly in these sediments. Both sediment types act as sinks for hydrogen sulfide and sulfate. An inner-sedimentary sulfur cycle is proposed to couple iron, manganese and phosphorus cycling with the degradation of organic matter. Nutrient cycling at the sediment-water interface might thus be driven by a microbially regulated electron pumping mechanism. The results contribute to a better understanding of the role of sediment processes in the lake's internal phosphorus cycle and its seasonal dynamics.     

Simultaneous operation of opposing reaction mechanisms: The influence of matrix heterogeneity on post-kinematic garnet crystallization in an inverted metamorphic sequence

Metapelites from the inverted Barrovian sequence in the Sikkim Himalaya (northeast India) are shown to be largely continuous with respect to their bulk rock compositions, microstructures and pressure–temperature–time–deformation (P–T–t–D) histories. However, the upper garnet–lower staurolite zone demarcates a region of microstructurally anomalous post-kinematic garnet populations contained within strongly segregated matrices. The different microstructures within samples from this region cannot be attributed to differences in their thermobarometric histories or bulk compositions, but are instead interpreted to represent an otherwise unexposed level of the Daling Group that is now exposed along a post-metamorphic thrust splay. These heterogeneous samples contain several discrete garnet populations that progressively crystallized with increasing P–T. Garnet populations that experienced the most protracted growth now form complex polycrystals that exhibit crystallographically controlled and morphologically irregular interfaces adjacent to micaceous and quartzofeldspathic domains respectively. Electron backscatter diffraction indicates that these polycrystalline garnet structures contain numerous coalesced porphyroblasts that are structurally uncorrelated across their grain boundaries. However, a crystallographically preferred orientation at the polycrystal scale is interpreted to derive from epitaxial crystallization of early-formed garnet porphyroblasts on precursor mica. Later-nucleated porphyroblasts within polycrystals preferentially concentrated towards quartzofeldspathic domains, with the overall nucleation distribution likely controlled by a complex interplay between chemical heterogeneities, strain partitioning and epitaxial crystallization. The subsequent growth of these polycrystals was equally spatially heterogeneous; it was moderated by differences in the efficiency of grain boundary transfer between quartzofeldspathic and micaceous domains that precluded thin section-scale chemical equilibration. In contrast to samples from Sikkim containing more typical porphyroblastic populations in continuous and disseminated matrices, heterogeneous availability of garnet-forming components within this strongly layered matrix is shown to have resulted in grain-scale variations in growth rates and the spatial juxtapositioning of interface-controlled microstructures and locally equilibrated chemical compositions with those that were transport controlled.     

Geological Characteristics and Occurrence of Gold in the Xiling Gold Deposit,Jiaodong Peninsula北大核心CSCD

西岭金矿床是胶东金矿集区内近来新发现的超大型破碎蚀变岩型金矿床(475吨@4.56 g/t),位于著名的三山岛金矿床的东侧。本文在详实的野外地质观察的基础上,系统介绍了西岭金矿床的基础地质特征,并运用光学显微镜和扫描电镜观察,结合电子探针分析,系统研究了西岭金矿床金的赋存状态。西岭金矿床大量金矿物(银金矿和自然金)主要赋存在Ⅱ阶段石英-黄铁矿和Ⅲ阶段灰石英-多金属硫化物脉中。西岭金矿床金矿物主要有晶隙金、裂隙金和包体金三种赋存状态,以晶隙金为主。金的主要载体矿物为黄铁矿,次为石英、黄铜矿和方铅矿等。金矿物粒度大小包括粗粒金、中粒金、细粒金和微粒金,以细粒-微粒为主。金矿物形态有粒状、叶片状、线状、钩状、枝杈状和哑铃状等,以粒状为主。金矿物成分以Au和Ag为主,含微量的Cu、Cr、Fe、Ni、Te、S等元素。金成色为685~831,以银金矿为主,含少量自然金。综合地质和地球化学特征,西岭金矿床为蚀变岩型金矿床,是由早白垩世中温岩浆热液充填-交代形成。     

中国首次发现的氟闪叶石矿物学特征

闪叶石族矿物是富含Sr、Na、Ca和Ba等的钛硅酸盐矿物的总称,迄今共有19个矿物种,其中的氟闪叶石矿物首次发现于巴西Serrote山碱性岩中。本文利用电子探针和X射线衍射仪等分析测试手段,从化学成分和晶体结构等方面对产出于中国辽宁赛马碱性岩体中的闪叶石族矿物进行了详细的矿物学特征研究,发现其中常呈柱状、针状和纤维状集合体产出的闪叶石的晶体化学式为(Sr_1.00Na_1.00)_Σ2.00Ti₂(Na_1.98Sr_0.33Mn_0.26K_0.12Mg_0.10Ca_0.09Ba_0.05)_Σ2.93(Ti_0.69Fe³⁺_0.33Al_0.02)_Σ1.04(Si_3.80O₁₄) O₂(F_1.16OH_0.84)_Σ2.00,属于单斜晶系,空间群为C2/m,晶胞参数a=19.271 9(8) Å,b=7.077 9(3) Å, c=5.388 2(2) Å, β=96.780(2)°, V=729.84(5) ų, Z=2。上述矿物学特征均与巴西发现的新矿物氟闪叶石的矿物学特征一致,表明赛马碱性岩体产出的氟闪叶石堪称该矿物种在中国的首次发现。不仅如此,赛马碱性岩体也有闪叶石产出,而且,迄今已发现多个新矿物,寓示该岩体仍有良好的新矿物发现前景。     

西藏帮布勒矽卡岩型铅锌矿床闪锌矿化学成分特征及其地质意义

帮布勒矿床是近年来在西藏冈底斯—念青唐古拉多金属成矿带西段新发现的大型矽卡岩型Pb-Zn矿床。闪锌矿作为该矿床的主要矿石矿物之一,其矿相学特征及化学组分对于揭示成矿物理化学条件和流体演化过程具有重要意义。本文选取帮布勒矿床近端及远端矽卡岩中不同世代闪锌矿开展详细的显微结构观察和电子探针成分研究。结果表明,帮布勒矿床闪锌矿可划分为2个世代:第Ⅰ世代闪锌矿主要产于近端矽卡岩,呈暗红色-棕红色,常与乳滴状黄铜矿共生,并交代他形磁铁矿、磁黄铁矿,Fe元素含量较高(部分闪锌矿Fe含量>10%),Zn/Fe值<10;第Ⅱ世代闪锌矿可进一步分为两类:第一类(Ⅱa)闪锌矿在近端及远端矽卡岩中均有发育,呈棕黄色,充填于辉石、石榴子石等矽卡岩矿物间及其裂隙中;第二类(Ⅱb)闪锌矿主要产于远端矽卡岩中,呈黄色-浅黄色,与方铅矿和石英共生,第Ⅱ世代闪锌矿相比于第Ⅰ世代闪锌矿Fe、Mn含量明显偏低,Zn含量较高。闪锌矿Fe元素温度计估算结果显示,从第Ⅰ世代至第Ⅱ世代成矿温度逐渐降低,分别为160～314℃、138～157℃,与闪锌矿Zn/Fe比值指示结果一致。综上证据,本文认为帮布勒矿床早期成矿流体...     

黔西南架底金矿床载金黄铁矿的矿物学特征及金的赋存规律研究

黔西南地区是中国卡林型金矿的主要产地之一,架底金矿作为黔西南地区近年来在玄武岩中新发现的卡林型金矿床,其金的赋存状态一直备受关注。前人研究表明,含砷黄铁矿是架底金矿的主要载金矿物,然而对架底金矿载金黄铁矿以及金的赋存规律一直缺乏深入的研究。文章结合野外实际调研以及室内显微岩相观察研究,首先对矿区黄铁矿进行了期次的划分;然后利用电子探针微区成分分析方法对不同期次的黄铁矿进行研究,结果显示:架底金矿的黄铁矿中,S、As具有明显的负相关性,Au、As存在一定的相关关系,成矿前黄铁矿与成矿期、成矿后的黄铁矿核部具高S、Fe,低As、Au等相似的特征,成矿期黄铁矿的环带具高As、Au的特征,与成矿后的环带(高As不含Au)相比较具明显差异,两者属于不同的热液事件。据此判断矿区载金黄铁矿的结晶顺序为:草莓状低砷无环带黄铁矿→含砷环带黄铁矿(含金)以及均质无环带的细粒黄铁矿→高砷环带黄铁矿(不含金)。这一结论对架底金矿找矿勘查工作具有一定的指示意义。     

基于电离层电子含量变化率的周跳探测方法

推导了利用GNSS双频数据的基于电离层电子含量(TEC)变化率的周跳探测方法,分析了电离层平静期和活跃期的TEC变化率,并认为对1s采样率的数据来说无论是否发生电磁暴都不影响TEC变化率法的使用,通过实验证明TEC变化率法能对1s采样率数据中的、其它周跳探测方法较难探测的小周跳进行探测,而联合利用TEC变化率法和MW法可对各自不敏感的周跳组合进行有效探测,实验证明:联合法对电离层平静期和活跃期中、采样间隔为1s的数据中的周跳都具有很高的探测成功率。