Abstract:Stusdy of the oxide minerals and measurement of the megnetic properties of about 100 samples distributed over a 475m continuous drillcore section from the uppermost part of extrusive sequence of the Troodos, Cyprus, ophiolite close to 35°03´N, 33°10´ E in the vicinity of Malounda yields the following major results: -Low temperature alteration is intense to a depth of 260 m, below which it is relatively much subdued. -Saturation magnetization, natural remanence intensity and initial suscep- }ibility all increase continuously with depth throughout the section. -Curie temperature decreases with depth to 260 m, below which a change in the style in the thermal decay of magnetization behaviour takes place. -Pillowed and massive flows differ in their magnetic properties. The rdsults are consistent with the downwards decrease in low temperature alteration previously noted from the distribution of secondary minerals. The downwards variations in magnetic properties closely follow in both sense a.nd magnitude of the trends observed in DSDP Hole 417A. This supports the inter- pratation of the upper, reddened facies of the Troodos extrusive sequence as being due to prolonged drawdown of cold sea water, and suggests that the magnetization of at least the upper part of the Troodos ophiolite is a reliable guide to ocean crust magnetization.
Abstract:Lei gong mo,a kind of Tektites in Chaina,is black glassy objects found only in the Hainau island and the Lei Zhou Peninsula. They are genetically related to the Tektites in the Australasian strewn field. Their shapes present predom- inately as water-drop and bullet, and some of them are platy. Its dented surface and fine close lamellatiori indicate that they were Liquid drops freezed by rapid cooling in the space and droped down to the earth. The diagram show- ing the major oxide variation of Lei gong mo indicates that they are different from the glass in the cosmos. Lei gong mo has REE pattern similar to normal Australasian Tektite and terrestrial shale and basalt. K and U abundances also indicate that Lei gong mo belongs to terrestrial rock. It is concluded that Lei gong mo were formed by impacting of a very large meteorite on the surface of the earth.
Abstract:In making a survey of Bayinuoergong rock mass in the north of Alxa Zuoqi region, Nei Monggol (Inner Mongolia), the authors have discovered a kind of polyclic spheroids with diameter of 10-14cm. They occur in the Hercynian granites in the form of accumulation and may have been the paticular granitic inclusions resulted from the transformation of sedimentary nudules during the long geology history. The authors suggest the following sequence in development of transformations development of sedimentary nudules-metamorphism-->remel- ting and granitization. This sequence eras supported both by the composition (mineral and chemistry) and the texture (or structure) of the spheroids and their round rocks.
Abstract:In compiling the map of China metamorphic petrology, the author has re- viewed more than thirty ordinary petrochemistry methods in regard to their character and application, and he has noticed there are two erroneous tenden- cies in the application of these methods both in our country and abroad, one of them only used one or two petrochemistry methods in restoring the original rocks, the other throwed doubt on the effectiveness of all petrochemistry met- hods. The author analysed the causes which produced above two erroneous tendencies. Two principles of petrochemistry methods are discussed in this paper and considered essentially to be true. The first is that the regional metamorphism is equichemical, i. e. there is no chemical change in the rocks in the processes of metamorphism, except their HBO and CO2 content. The second is that the chemical composition should be different between the various genetic types of original rocks either in their major elements or minor elements, and even in the relationshipes of them. For the correct use of the petrochemistry methods the author puts for- ward four items of suggestion, in which should be especially emphasized is that oue should pay attention to the chemical peculiarities of various volcanic-sedi- mentary rock types and their distributive characters in various petrochemis- try diagrams. In addition, It is necessary to have an intimate understanding of selected methods including their theoretical foundation,applicability, advantages and their defects.
Abstract:In placers, many iron spheres, 0.1-0.5mm in size were found, they are often composed of two or three layers of different phases. The outer shell consists of magnetite, tvustite and maghemite. The inner shell is of Ni-Fe metal phase which consists of kamacite and taenite, they are composed mainly of iron, minor nickel, a few of Si (various in composition from 0.1-3 % ) and a trace amounts of Cr, Cu and Co. The centre part is sometimes composed of Si-Fe core of gupeiite and xifengite. The iron sphere's shape is very characteristic, it is produced by the migra- tion of the melting material from head to tail on outer surface of the iron spheres after friction in the atmosphere. The head of the globule is round and the tail is flat with a few concentric circular troughs and a cavity is observed in the centre, thus forming typical button-like shape. The surface of iron spheres put up an appearances of wrinkles, brain pat- terns, and scales. All these characters indicate that iron spheres are of cosmic genesis derived from extraterrestrial space. Gupeiite Opaque, black to steel-grey with metallic luster. G (cal.)7.29，strongly magnetic, streak and powder black. Under the reflect microscope, it appears greyish-white with yellow tint in air, similar to polyxene. Isotropic, no cleavage, no twining, no internal reflec- Lion, polishing hardness, TiC>gupeiite, having a good polished section. VHN50-100 494.2-514.1。 The analyses calculated on the basis of four atoms, its formula.r is Fe 2.971 Ni 0.027 Mn 0.023 Si 0.979，and the ideal formular is Fe3Si. Its patterns identical with syth.etic FesSi, which has a facecentered cubic unite cell and a space group Fm3m. High-angles extrapolation graphs gave the cell dimension a 5.670 A，Z=4. Xifengite Steel grey, metallic luster, G(cal.)6.43. brittle. Strongly magnetite, streak and power being black. In plan light, xifengite is grey with yellowish tint is air, which much resembles pentlandite, but not so under crossed polaxs. It is a moderatly anisotropic mineral, With bluish grey, brownish anisotropism. Bireflectance and reflectance pleoehTOism are not detectable by eye, no cleaveage. Occurs asxeno- morphic aggregates, VHN50633-694. The analyses are calculated on the basis of eight atoms and its formula is Fe4.905Ni0.018Mn0.015Si3.062. The ideal formula is Fe5Si3. Xifengite is hexagonal with cell dimensions a 6.759，c 4.720 A，and a space group P63/man Z=2.
Abstract:in the phase quantitative analysis by use fo the x-ray diffraction, the contents of minerals are determined by th.e intensity of diffraction. But many factors have influence over the intensity. The prefrred orientation described in this paper is an important influential factor. The difficulty for phase quantitative analysis of talc qy use of the x-ray diffraction method is the preferred orientation. Because talc occurs in foliated, scaly, or fibrous aggregates. When the samples prepared by usual method, it shows random orientations. The intensites are various. Therefore the phase qu- antitative analysis can not be done. In this paper the "nonpressure method of prepared the samples" is described. It eliminated the preferred orientations completely. Then the satisfactory results are obtained. This method is not only suitable for talc, but is also applicable for all other scaly, slaty, or fibrous mi- nerals of sheet silicates.
Abstract:Potassium has to be determined accurately in studies of geological age by the potassium-argon method. This paper recommends a procedure for the accurate determination of potassium. In order to overcome the interferences from other elements in rocks and minerals, potassium was separated from aliquots of sample solutions by cation-exchange chromatography on Dowex 50W × 4 or 71-616 resin columns Solutions were prepared gravimetrically instead of volu- metrically. Possible contamination due to potassium in glassware was avoided by the use of platinum, quartz and polyethIend vessels. The accuracy may be greatly raised after the determination of potassium by AAS. Six standard samples were measured many times in this way, and the re- sups agreed well with those obtained from laboratories in U. S. A. and Austra- lia. The relative standard deviations do not exceed 3% of the mean result within 1-10% of potassium. The procedure may be applied to the accurate determination of potassium in K-Ar dating and other fields.
Abstract:The electron probe is indispensable equipment for assessment of rocks and ores in geological works. Since 1975, we analysed a lot of the ores and minerals of gold and silver from uiangxi, Henan, province et al, not only for appraising the content of gold, silver, electrum, miargyrite et al and observed its occur- rence, but also made a careful study of exist condition of the useful elements and useless elements in the ores and thereby provided foundationaI data for ore's synthetical evaluation. In this paper, a summarized account has been given the methods of qualitative analysis and quantitative analysis of gold- silver composite samples with electron probe x-ray microanalyzer. (1) "Z. A.F”method; (2) Method of quantitative analysis of standard samples of Au-Ag alloys; (3) Method of quantitative analysis of standard samples resemble mineral; (4) Method of quantitative analysis by proof read curve; (5) Method of quantitative analysis of silver sulphide mineral and its app- lication.
Abstract:This paper deals with the determination of trace amount of tin in geological materials. The advantages of both hydride method and graphite furnace meth- od were combined. The generated gaseous hydride was dried. cooled with liquid nitrogen and finally introduced into the interior of the graphite tube and atomized. The detection limit of the method was 0.035 ppm and the sensitivi- ty was 0.024 ng/ml/1%，
Abstract:This peper deals with the error distributions of trace elements analysis, such as data processing, estimation of error, and quality monitoring. The author su- ggests to calculate the statistic parameters errors and deviations of real sample analysis by formulas based on the normal destribution and then expressing them in corrr.sponding units,
Abstract:This paper discusses the problems of background correction in the determin- ation of trace elements for geological rock samples by X-Ray fluorescence spe- ctrometiy. An approach of background correction- -inherent background and background equation--was suggested and satisfactory result was obtained.
Abstract:A sensitive analysis for determination of 27 elements by ICP-AEAS powder method is studied. Sulphur is used as carrier in the buffer. The sensitivity of this method is generally increased in 2-20 fold. The detection limits and the range of determination for 27 elements are reported.
Abstract:A rapid and simple determination of thorium in minerals and metallugical processing products by XRF analysis is described. It is bisect ou the use of ions exchange paper with static sorption for 10 minutes in 0.5-2.0 N hydrochloric acid. The coefficient of variation for sample containing 0.1% Th is 3.26%(n= 15).The method can be used for determination of thorium within the range of 0.00x-x%.
Abstract:A uew simple paper-chromatography for the colorimetric determination of micro amount of gold with thio-Michlers ketone(TMKI in ores has been studi- ed. The sample solution in hydrochloric acid medium was introduced on chro- matographic paper. The developing medium was alcohol-acetic acid-water solu- tion and ascending process was applied. The chromatogram was developed with 0.3% TMK of ethyl alcohol solution. The Rf value of gold was found to be 0 .99, the other elements such as Cu, Ni,Co, Se, As, Ag, Mo and Te were less than 0.82. The mekhod could be applied to the determination of 0.OOx-O.x g/T gold an ores.
Abstract:The sample solution in 2 N nitric acid tnediurn was extracted with trioctyl- phosphine oxide (TOPO) in cyclo,hexane solution in the present of ascobic acid, boric acid and aluminium salts, and backextracting with 2 N-HN03 contain ing 0.8% NH4F solution. Uranium was determined in TOPO layer with 5-Br- PADa1P, and thorium was determined in aqueous solution with arsenazo III.Its C. V. for sample containing 1.3ppm U and 1.6ppm Th were 9·0% and 3 .6% respectively (n=8).
Abstract:The behaviour of enriching silver by extraction chromatography with N263 liquid resin w"as studied. The optimum conditions of the adsorption and elu- tion of silver were examined: The elimination and interference of foreign ions were tested. This method could detect more than O.Ox ppm of silver in ores (sample taken :5g0.
