Abstract:As the metallogenic parent rocks of the Shizhuyuan large-sized rare element-nonferrous metallic deposit, the Qianlishan complex granite body is characterized by high silica, peraluminous rocks, rich incompatible elements, strong negative Eu anomalies, low sNd, and relative high (87Sr/86Sr)i, 207Pb/204Pb and δ18O values. These features suggest that the Qianlishan rock body was derived from the crustal material, thus belonging to continental crust transformation type. Furthermore, weak negative Ce anomalies and comparatively old model ages imply that the original magma was formed mainly by partial melting of the unexposed middle Proterozoic metasedimentary rocks in the study area.

Abstract:The Cenozoic volcanics in Tengchong area are of calc-alkaline series and might be divided into four eruption stages (N2, Q1, Q3, and Q4), which make up two magmatic cycles composed of basalt→dacite (Nz→Q1) and basalt→andesite (Q-}Q4) respectively.Studies by means of Pearce ratio diagram show that fractional crystallization seems to be the major cause for variation in petrochemical composition. Basalts of the first cycle might have originated from partial melting of the upper mantle. The fractional crystallization of the (Pl＋Cpx土O1士Mt) assemblage was the main factor responsible for the formation of dacite and the assimilation of small amounts of crustal materials. This cycle shows features of bimodal igneous suite in a tensional tectonic environment. Basalts in the second cycle might have resulted from partial melting of the early subducted oceanic crust, with the fractional crystallization of the (Mt＋PI＋Cpx士Opx) assemblage being the main factor for the formation of andesite. This cycle has characteristics of island arc volcanics, being real post-collision arc volcanics.

Abstract:Hydrogen and oxygen isotopic composition of altered rocks and ore-forming fluids proves to be one of the best indicators in the genetic study of hydrothermal deposits,and the determination of ini tial parameters of hydrogen and oxygen isotopes in the process of water_rock exchange seems to be of key importance. Based on an investigation into hydrogen and oxygen isotopic composition backgrounds of major geological bodies related to gold deposits in Jiaodong region, the present paper points out that the hydrogen and oxygen isotope background values are δ180=7.8% and δD=-110% for the Early Yanshanian "Linglong" medium-coarse grained adamellite (Luanjiahe type), δ180=10.0% and δD=-90% for the Late Yanshanian Guojialing type porphyritic granodiorite, δ180=8.5% and δD=-90% for the Kunyushan complex granitic batholith,and δ180=5.1-11.3%o and δD=-81--96%o for the metamorphic rocks of Jiaodong Group. These data show that the protoliths of the Jiaodong Group contained both mantlederived intermediate-basic components and crust-derived argillaceous-arenaceous materials,whereas the Guojialing type granite and regional intermediate-basic dikes are likely pro_ ducts of remelting and crystallization differentiation of other geological bodies in this region. Hydrogen and oxygen isotopic data of some subordinate rock bodies in this region are also given in this paper.

Abstract:Diagrams showing relationship of the temperature (T), An and △131一131 (OR σ)of sodic plagioclase were advanced in succession by Christie (1962), Smith(1972) and Zhang Yijun(1985). Later, the formulae for deformation temperature of sodic plagioclase were put forward by Zhang Yijun. Nevertheless, in view of the inconvenience of the diagram, the uncertainty of the dividing point in the formulae and the nonlinear relationship amongσ，An and T, we present a new method for calculating the temperature of the deformation-artificial neural network，which has accurate nonlinear projection.In this paper, an account is first given about the study of the deformation thermometer,followed by a description of the ANN (Artificial Neural Network) model. With this model, the temperature of the deformation is estimated. A comparison shows that the artificial neural network is very effective in the estimation of the deformation temperature.

Abstract:In the geological teaching and geological photographic processes,the authors foundin 1988 phenomena similar to groove cast and flute cast at the bottom surface of sandstone deposited in shallow water, which are different from examples of groove cast andflute cast abroad cited in textbooks of China on sedimentary petrology in two aspects:(1) the groove cast observed is current scour cast rather than tool impression-scoringcast,(2) sediments underlying the observed groove cast and flute cast are arenaceousinstead of argillaceous. The discovery of such phenomena is a supplement and improve-ment to the phenomena of groove cast and flute cast,and is hence of great significancein finding out the origin of groove cast and flute cast as well as filling in the gaps ingroove cast and flute cast examples of China in textbooks of sedimentary petrology.

Abstract:Chemical compositions of spinet found in natural rocks such as peridotite and lunar rock and synthesized or reequilibrated in simple and complex systems show that, at mid-dle-low pressure, spinet coexisting with olivine may contain some Si whose solubility increases with temperature and pressure. Using least squares regression, we fitted the experimental data in a simple system to a simple thermodynamic model and obtained the relation between variation in free energy for reaction Mg2SiO4(Ol)= Mg4SiO4 (Sp) and temperature. The result obtained is very similar to that deduced by Navrotsky and Akaogi(1984) from calorimetric and high pressure phase equibrium data. This good agree-went proves that, at middle-low pressure, Si may exist in the form of silicate spinel (Mg2SiO4) in picotite, and the activity of Mg2SiO4 component in MgCr2O4-Mg2SiO4 spi-net solid solution can be expressed as aspMg2sio4=(NspMg/2)2.(Nspsi)2.(Nspi represents num- ber of Mg and Si cations in unit structure formula of spinet on the basis of 402-).This implies that MgCr2O4-Mg2SiO4 spinet solid solution has perfect short range order.The experimental and modeled results indicate that the solubility of Si in chrome spinel is very sensitive to temperature and hence may serve as a potential geothermometer.

Abstract:Natural thermoluminescence determination was made for quartz of different ore- forming stages from the Xiangshan uranium deposit,and natural thermoluminescence characteristics of quartz samples were studied in combination with XRFS and EPR data. The results show that quartz samples of different ore-forming stages exhibit notable-differences in such aspects of natural thermoluminescence as its intensity and peak sha-pe characteristics of its spectral line. Quartz thermoluminescence results from the centers whose quantity is bound up with total amounts of uranium and thorium. Thethermoluminescence intensity of quartz is in inverse growth and decline relationshipwith the color of quartz,and the peak shape characteristics of the thermoluminescencespectral line represent the formation temperature of quartz and the thermal events thatthe quartz experienced after its formation.

Abstract:A large number of microspherolites selected from Ningxiang lamproite, Hunan Pro- vince, South China, were examined and analysed by several approaches. In terms of their physical properties and chemical compositions, three groups of microspherolites can be distinguished. They are considered as volcanic microspherolites although those from sedimentary rocks and ocean floor are traditionally attributed to cosmic dusts. The microspherolites are described as of the following three groups:(1)nonmag- netic group, which is colorless and transparent, pale-yellow and semitransparent to dark yellow and opaque; (2) magnetic group, which is dark in color; (3)strong magnetic group, which is steel grey and dominated by iron. In addition, some volcanic dusts,such as magmatic splashed fragments and blocks, can also be observed. The features of microspherolites are varied, and their facies and textures show evidently that they are products of volcanism. Chemical compositions of these microspherolites vary in a wide range, from iron deficiency to iron dominance: (I)Fe-poor type, which is rich in Si, Mg, Ca and P,but poor in Ti, Mn and K; (2) Fe-rich type, which is high in Si, Ti, Mn and K,but poor in Ca, Mg and P; (3) Fe-high type, which is dominated by Fe. Lamproite microspherolites are characterized by diversity both in chemical composilion and in physical properties. It is concluded that liquation took place in the magma chamber after the emplacement of lamproite magma in the deep crust, and afterwards microspherolites were formed as a result of rapid cooling and quenching during volcanic eruption.

Abstract:It is discovered that zircons (2400 Ma1士)from charnockite and granulite in Lower Jining Group of Inner Mongolia and Sanggan Group of Hebei exhibit euhedral growth zoning and compositional zonation of increasing HfO2 content and decreasing ZrO2/HfO2 ratio from the core to the edge of a crystal, suggesting that these zircons grew during magrnatic crystallization and differentiation. Nevertheless,the edges of these zircons are rounded, and their compositional zonation shows resemblance to that of recrystallized zircons in metamorphism,implying that these zircons have experienced metamorphism, with recrystallization growth along their edges. As for the charnockite studied in this paper, the authors consider that its formation underwent a cycle of protolith metamorphism metamorphic rock anatexts magma (TTG type) crystallization and differentiation TTG type granite or charnockite, (unaer high pressure) metamorphism existing charnockite ) which seems to be one of the materials exchange modes between the crust and the mantle and leads to the formation of the stratified structure of the earth. Zircons of 1980 Ma士 found in granulite of Upper Jining Group exhibit rounded growth zoning and compositional variation trend opposite to that of magmatogenic zircons,tending to decrease in HfO2 and increase in ZrO2/HfOz from the core to the edge of the crystal,which suggests that these zircons are of metamorphic recrystallization origin.

Abstract:Palygorskite occurs in clay sediments at the top of the Miocene Xiacaowan Forma- tion. Its crystals assume fibrous, acicular and rod forms, and the aggregates vary greatly in shape. Its morphological and physical features are somewhat different from features of hydrothermal palygorskite from Quanjiao, Anhui Province. Palygorskite from the study area is in accord with palygorskite from Attapulgs,U. S. A, in chemical composition, both characterized by high TiO2, Fe203, MgO, CaO,Na2O and K20 and low A1203 and Si02. Crystallochemically, it is of a dioctahedral-triotahedral transitional type rich in Fe3+ and Mg2+ and deficient in A13+. In contrast, hy-drothermal palygorskite from Quanjiao is noted for low Fe3+ and Mg2+ and high Al3+.Palygorskite from the study area belongs to monoclinic system, with degree of crystallization lower than that of hydrothermal orthorhombic palygorskite from Quanjiao. The substitution of Fe3+ and A13+ for Mg2+ might cause distortion in its crystal lattice. The absorbability of palygorskite is related to such factors as its grain size, specific surface area and acid active treatment. Acid treatment can enlarge the specific surface area and microporous volume of palygorskite, hence raising its absorbability.

Abstract:An integrated study of apatites from Haizhou type phosphorite deposits was madein such aspects as their mineral associations, chemical composition,REE analyses,inf-rared absorption spectra,and X-ray diffraction data. The results show that theseapatites were formed by metamorphic transformation-mobilization and migmatized meta-somatic recrystallization, and might be classified into two types:fluorapatite and fran-colite. Unit cell parameters a0=9.3653-9.3819nm,c0=6.8797 - 6.8936nm. Crystallo-chemical formulae (Ca5.00Fe0.02Sr0.01TR0.01)5.04[(P2.99C0.04)3.03O12]F0.08 and(Ca4.94Fe0.02 Mg0.02Sr0.01TR0.01)5.00 [(P2.90Ti0.02Si0.15)3.07)O12]F0.77). These data further demonstrate that the formationof Haizhou type phosphorite deposits is attributed mainly to deposition and metamor-phic transformation and next to migmatization-metasomatism.