摘要:The authors have studied the oxygen and carbon ssotopic compositions of the carbonate wall rocks from the Dahongshan mining area, Yunnan Province and, combining with geological features, laid emphasis on the study of the underlying marble which is most greatly affected by the ancient volcanic erup- tion. The analyses of 31 samples indicate that there is a distinct pattern for the variation of oxygen and carbon isotopic compositions, which is in coinci- dence with the pattern of the central-volcanic eruption and volcanic neck emplacement inferred from geological and petrological studies. The oxygen and carbon isotopic data also show that the carbona.tite rocks in the Dahongshan area were most likely formed by melting of the marble. As a supplement to the data appeared in the paper[1], the oxygen and carbon isotopic data of 13 siderite samples are presented here. They may be characteristic of the moder- ately metamorphosed volcanic-sedimentary siderites.
摘要:Seven pairs of coexisting ortho-and clino-pyroxene from granulites of var- ious chemical series in Qianan county have been researched, and the temper- aturepressure condition of Early-Archean granulite facies metamorphism of this area is discussed. The equilibrium temperatures of coexisting twopyroxene calculated accord- ing to Wood and Banno's methods (1973) and to We11's method (1977) were very close to each other, with an average value of 845土60℃.The pressure estimated by Ca/Ca+blg of ortho-pyroxene coexisting with diopside (Nehru 1976) and by the tschermakite content of clino-pyroxene coexisting with an- orthite and quartz (Wood 1976) were about 8Kb at that temperature. Corre- sponding to a geothermal gradient of 300℃/Km, early-Archean metamorphism of Qianan is approaching to a low pressure metamorphic facies series. The equilib- rium temperature of coexsting Garnet-biotite was 575-694 ℃. It is implied that these rocks have also undergone the superimposed retrograde metamor- phism of amphibolite facies.
摘要:According to the study of the formation of andalusites and sillimenites aoct it，s geologicalal significance of the Mesozoic regional metamorphic belt along the coast in Fujian Province the writer suggests that the types of the formation of those two kinds of mineral are very complax, i. e. they represent a very different geological occurrences. It is not suitable to suggest that the appearance of andalusites and sillimanites hold a special characteristic of P-T condition Which is the base of subdivision of metamorphic phase. The writer suggests that the metamorphic belt in this region was the result of the Mesozoic primary volcanic-sediments by the processes of diagenesis, regional metamorphism, migmatization, and the empeacemet of granite, and the different types of aadalusiteand sillimaates were formed by the transformation of the heat energy in each period of those processes that have been mensioned.
摘要:Xilingolite occurs on skarn zone developed in the northern side of the iron ore deposit of Chaobuleng field in Xilingola district, Inner Mongolia Autonomous Region, People's Republic of China. tt usually occurs in anhedral granular. forms, or in distinct prismatic, crys- tals. The mineral is lead grey. Density (g/cm3) 7.08 (obs)，VHN50 103.1kg/mm2. In polished section, it is light bluish white under reflected light with a dis- tinct reflection pleochroism, white// e1 to b-axis and bluish white ⊥ ar to b-axis, both in air and oil. Anisotropic properties of the crystal are notable. Reflec- tances measured in air; (wave length, Rmax. Rmin.) 480nm-46.8, 44.3; 546nm- 44.5, 41.8; 589nm-43.8; 40.9; 656nm-43.0, 39.9. Its chemical formula is Pb3xBi2-2x/3S6 where X≈0.3. X-ray single crystal study showed it to be monoclinic, C 2/m, C2 or Cm, ao 13.65, b0 4.078, c0 20.68A，β 93.0°, Z=4. The strongest lines in the powder diffraction pattern are; 3.699(3)(112)，3.386(1)(113)， 3.109(2)(114)，2.932(4)(312)，2.840(2)(115)，2.177(9)(407)， 2.140(1)(209), 2.073(8)(317), 2.051(7)(514)，1.955(7)(0 2 3)， 1.788(6)(2 0 11)。 Although the chemical composition and unit cell parameters of the present mineral are very close to those of lillianite, but the crystal structures of them are different. The name is for the locality.
摘要:There are two types of fused crusts of meteorites;the primary and the se- condary. The former may begin to form once the meteoritic body enters the atmosphere of the earth, while the latter may be created on the new surface formed when the meteorite is broken or shattered due to unbalanced stress and strain. The primary fused crust is greyish black, without the original me- teoritic surface characteristics but with evident gaseous prints, vesicles, residue and new accretions formed during falling of the meteorite. The micro stratifi- cation of the crust is distinct, four layers can, in general, be recognized;(I) Hyaline fused crust layer. It is the outmost true fused layer consisting ma.in- 1y of dark glass, incompletely developed, and 0一120µ in thicknesss(II ) Metal particle-dark hyaline layer. Abundant dusty exdissolved metal particles and mag- netite crystallites are found set in a glassy groundmass. This layer is comple- tely developed and from 20 to 160µ thick;(llI ) Bamboo-leaf-like silicate mic- rocrystalline layer. Bamboo-leaf-like microcrystalline silicate minerals are found set in a dark glassy groundmass and this layer is about 260-3001 thick; a.nd ( IV ) Troilite leakage-cemented layer. In this layer, remelting, permeating and cementing phenomena are found only with troilite, and other silicate minerals basically remain unchanged, these producing an obsure boundary between this layer and the underlying one. The thickness of this layer is 200-500µ.
摘要:Ferroselite is found in sedimentary uranium deposit in Sichuan province. It occurs in grey一lack sandstone. The ferroselite is dark-grey in colour, with metallic luster on its fresh sur- face. Hv =630kg/mm2(25g)，Dx=7.212g/cm3, refraction colour is from milk-whi- to to purplish, refraction polarizing Rg=purplish, Rm=yellowish-white, RP= milk-yellow to yellowish. Refraction indices are Rg 45.75-57.31(440-660nm)，Rp 39.41-44.50(440-660 nm) and the colour indices of ferroselite are Rvis=50.30, 41.90, X=0.347, 0.341, Y=0.342, 0.340, λd=580nm, 582nm, Pc=0.106, 0.053. The chemical composition of ferroselite indudes Fe 28.64, 27.43,Se 71.59, 71.62 and S 1.00, 0.44,totaling 101.23,99.39. The powder data of ferroselite are:3.04(4,011),2.88(6，101)，2.57(10，111)，2.48(9，120)，2.02(1，121)，1.88(10, 211), 1.79(3,002), 1.69(4,031)，1.58(1，131)，1.53(1,310)，1.456(4，122)，Unit- cell a=4.78A，b=5.755A，c=3.58A，v=98.48A, z=2.
摘要:Suanite, a mineral of magnesium borate, rarely occurs in nature. We have studied the conditions for its formation and stability by laboratory synthesis and hydrothermal experiments. The experiments were carried out in cold-seal vessels at the temperature of 350-500℃ and pressure of 200-1000 bars, with MgC03 as a starting material and H3BO3, Na2B40, and H3BO3 +NaCI as reactive solutions. Suanite, kotoite, szaibelyite and ludwigite were formed under these conditions. The experimets show,(1 )suanite occurs in a high-boron and magnesium, low-iron hydrothermal environment. It can be formed by reaction of MgCO3 with 1-3 M H3B03 or Na2B4O7 solutions under temperature of 500-600° C and pressure of 200一1000 bars. In the case of reaction of MgCO3 with relatively dilu- ted H3B03 solution and under the same P-T conditions, the product is kotoite instead of suanite.(2 ) Suanite is formed and stable at relatively high tempe- rature(500-600°)and may change into szaibelyite by hydration when tempera- ture drops below 450℃.(3 )Suanite is formed under a low CO2 partial pressure and a wide range of pH values and is stable when pH=5-9. From the results of the experiments, it is considered, that suanite may not be a typical skarn mineral. It seems most probable that suanite is formed by high-temperature metamorphism of sedimentary formations of hydrous magne- sium borates and boron-bearing magnesium carbona,tes. The hydrous borate mi- nerals, when undergo high-grade regional or contact metamorphism, would chan- ge into anhydrous borate minerals such as suanite and kotoife through dehy- dration. During the contact metamorphism of the magnesium-carbonate forma- tion, boron form formation iself and from endogenic hydrothermal solutions may also react with carbonates to form suanite. Therefore, it's reasonable that sua- nite is formed by hightemperature metamorphism of sediments.
摘要:Floatation in Clerici solution for density measuring is one of the most effective methods in the determination of the specific gravity of small mineral grains. It is only necessary to mix with water to succeed in getting a set of liquids of lower specific gravity decreased one after another by degrees than the concentrated Clerici solution at regular intervals. Experimental data show that a straight line relationship exists between the refractive index and specific gravity of Clerici solution. Both will decreases with increased temperature. The value of dN/dT(the change in index of refraction for each degree centigrade change in the temperature) is -X0.0004 and that of dD/dT (the change in density for each degree centigrade change in the temperature) is 士0 .001. For very accurate work a correction factor is necessary if the obtai- ring temperature is other than 19℃. A correction of specific gravity of plus or minus 0.001 per degree above or below 190C should be made. This method gives results reliable to the nearest士0.005-0.01 in specific gravity. The error of the specific gravity determination is to a certain extent relative to the size of the mineral and the skilled level of the operator. In this paper, the opera- tion sequence, the author's experience, the requirements, the matters needing attention etc. are related.
摘要:
摘要:The sample of meteorites was dissolved by heating with a mixture of HF and concentrated HNO3 in a closed Teflon Vessel The disso'ved mixture was treated with concentrated HCI to become HCI in medium, NaF was added as the masking agent and the pH was adjusted to 8-8 by the addition of a buffer solution of acetic acid and sodiuum acetate. Then a solution of TFA(trifluoroacetyl acetone) in benzene was added to extract Rh by chelate formation. Finally, gas chromatography was employed to determine quantitatively the TFA-Rh-chelate. This method was applied to the determination of a sample from the Jilin stone meteorites and the Rh content was found to be 0.14 ppm approximately.
摘要:A method forr ICP-AES determination of 31 trace elements in rocks with PAN enriching was atndied. Theae elements ware precipitated with PAN is a chloride solution of pH 8. The Precipitate was then dissolved in 5% HCI solutioa.The dissolved amounts of iron and aluminium wore so small that they could not cause interference is the determination. In this method the concentrations of Nb, Ta. Hf, Th, Sc, Cr, Ni, Ti, V, Ilsa, Pb, Zn, Sa, Cd, In, La, Ce, Pr,Nd,Sm. Ea. Gd, Tb, py, Ho, Er, Tm, Lu and V were determined simultaneously by ICP-AES method.
摘要:A method for the determination of Ag and Cd at ppb levels in gecchmic:el refernce samples by flameless atomic absorption spectrometry after separati..n with an anion-exchange resin was described The samples are digested with aqua regia. The resultant solutions of O.6N hydrochloric acid were passed through a column of 717 anion exchange resin, and eluted quantitatively with 30 ml 1.5N nitric acid. The amounts of Ag and Cd in the eluate were determined by flameless absorption spectrometry.
摘要:A`λ"type capillary nebuliaer was designed and used in hydridn goneration-flame atomic absorption analysis. In this design, the upper end of capillary nebulizer was ccnnected to the sample entering capihary of the iusfrument spectroter,while one cf its lower end was dipped into the sample solution and the other end into the potassium borohydride solution. The uptimum conditions for determination were selected and of some 14 elements of fhe indicated amounts wverefouud no intarfereace. A procedure of trace amount of bismuth in the water system sediments has been developed. The detection limit waa 0.009 ppm Bi, the relative standard deviation was 3.6-19.9% for 0.31-4.4ppm Bi in 8standard samples(n=6).
摘要:A method is suggested for spectrophmtometric determination of chlorine in ores.It is based on pyrolpsis of the sample a high temperature furnace, The chlorine is absorbed in the mixture solution of mercuric thiocyanate and ammonium ferric sulfate.
摘要:Use of common ion affect in chemical phase-analysis has been studied, In order to avoid the dissolubility of wollastonite and tunstite from the solution of complex samples, 1 ml of 5% sodium silicate-0.5% sodium tungstate mixed solution was added into the leaching liquor coataining 8%alnminium chloride. This method was applied far the determination of fluorite in ores with satisfactory result.
