Abstract:Ophiolites of Ailaoshan belt are composed of meta peridotite, cumulate complex and basic lava, in which lherzolite is similar to primary pyrolite, and harzburgite is relic pyrolite. The gabbro diabase pyroxene basalt series and the pyroxenite gabbro diorite albite basalt picritic basalt series were formed respectively by crystallization or crystallization differentiation of tholeiitic magma and picritic basaltic magma produced by partial melting of primary tholeiite; the former is characterized by oceanic ridge basalt, whereas the latter by paraoceanic ridge basalt, both formed in an environment of mid oceanic ridge. Their formation time was not later than Early Carboniferous (C1), and the emplacement took place before the formation of Late Triassic Yiwanshui Formation (T3 y).

Abstract:Based on petrological and trace element geochemical studies as well as an analysis of oreforming rock bodies and wall rocks for different types of ore deposits, the present paper has probed into the relationship between Mesozoic volcano-magmatic activity and metallization. It is held that Late Jurassic volcano-magmatic activity provided favorable wall rock and structural space for the ore-forming process, and that Early Cretaceous magmatic activity supplied ore-forming rock bodies as well as thermodynamic conditions. The subvolcano-magmatic intrusion of the latter period played the major role and reacted with different wall rocks, forming a series of ore deposit associations composed of porphyry copper and molybdenum deposits and epithermal silver, lead and zinc deposits.

Abstract:The REE content of tectonic rocks in the shear zone shows regular variation in the deformation process. When the intensity of deformation becomes stronger, the contents of various rare earth elements and the contents of LREE, HREE and REE increase obviously, but the REE patterns remain unchanged. Through equal ratio analysis of granitic tectonic rocks before and after deformation in Jiaonan orogenic belt, the authors have reached the conclusion that the variation of REE results mainly from volume deficiency. According to the function relation be- tween composition variation and volume deficiency, it is known that when granite changes into mylonite the volume deficiency ratio is 14.5%, and when granite changes into ultramylonite the volume deficiency ratio is 20%.

Abstract:Kunyang rift located on the western margin of Yangtze platform is tectonically equivalent to East Africa rift where there exist modern carbonatite volcanos. Guantianchang sector, through which a NE-trending concealed deep fault passes, is just located on the western edge of Wuding sea basin in the middle part of the rift. Therefore, the prerequisite for the formation of carbonatite volcanos exists there. Daqing subtype cupreous dolomite contains several kinds of igneous minerals frequently found in carbonatite such as albite, oligoclase, biotite, phlogopite, arfvedsonite (Guantian), zircon, rutile, fluor-apatite, in addition to plenty of trachytic-trachyandesitic volcaniclastic substances. The primary dolomites were igneous too. Rock constituents were derived from carbonatite once existent there, so rocks show textures and structures of carbonatite lava and volcaniclastic rocks. Therefore, they are a suite of carbonatite volcanic rocks, which include lava and volcaniclastic rocks. The magma that formed them originated from the mantle, and flew from craters to depressions to accumulate and form rocks. Stratified in form, the rocks lie from the upper part of Yinmin Formation (Pt 2y) to the bottom of Luoxie Formation (Pt2 l) and are in conformable contact with the overlying and underlying marine facies sedimentary rocks and stratiform volcaniclastic rocks. The rocks are associated with a suite of Na-rich alkaline rocks, equivalent to being associated with oceanic carbonatite. This suggests that they were formed in a submarine environment. Influenced by sea water, they extensively experienced chloritization, epidotization, silicification and limonitization with darkened rims of biotite.

Abstract:In this paper, the author first studied characteristics of tectonite of ductile shear deformation in the epimetamorphic microclastic rocks, and made classification of tectonite. Then, the difference of this tectonite from typical felsic mylonite was elaborated. Based on petrofabric characteristics and comprehensive analysis, the author holds that the deformation mechanism of tectonite was mainly intergranular movement and partly intragranular deformation, and that it occurred in the superzone of the crust at the depth of 5-8 km under the conditions of lower pressure and lower temperature.

Abstract:In this paper, the neodymium isotope composition and source materials of the meta-basement in central Jiangxi have been studied. The Presinian medium-grade metamorphosed sedimentary rocks have lower143Nd/144Nd ratio (0.511827—0.512052) and∈Nd(T) values (-3.60—+1.11) and older model ages (1597—2124 Ma), while the slightly metamorphosed Sinian sedimentary rocks have a bit higher143Nd/144Nd ratios (0.511918—0.512233) and ∈Nd(T) values (-0.320—-0.55) and younger model ages (1360—1405 Ma). The above neodymium isotope characteristics suggest that the Presinian metamorphic sedimentary rocks consist of old continental debris from Huaxia massif and volcanic materials derived from the mantle, being formed in an arc-type environment. The Sinian epimetamorphic sedimentary rocks were formed along the western active margin ofHuaxia paleocontinent, with their rockforming materials derived chiefly from eroded debris of Presinian metamorphic sedimentary rocks and a bit volcanic materials. The above study has provided important isotopic evidence for the argument that meta-basement in central Jiangxi belongs to Huaxia massif.

Abstract:Ankerite microclinite, a special type of rock, is closely related to the ore-forming process of massive sulfide deposits in the East Liaoning Proterozoic rift. Assuming rhythmic layering form, the rock is rich in K,B and Si and falls into the field of hot water deposition both in Al2O3-SiO2-(CaO MgO) diagram and in Fe-Mn-(Cu Ni Co) diagram. Its REE geochemistry is characterized by negative Ce anomaly and enrichment of LREE, and its Si isotopic geochemistry implies an origin of hot water deposition. As a sort of hot water sedimentary rock, it exhibits important ore-prospecting indicator significance. With this rock as an indicator, sulfide orebodies were discovered on the outskirts of the old mine.

Abstract:The names both in Chinese and English, chemical formula and other data of fifty new minrals which were approved by IMA CNMMN from July to Dec., 1992 and were published in various mineralogy magzines in countries are listed in this paper. These data of new minerals includ: crystallographic systems, space groups, unit cell parameters, main powder diffraction data (I,hkl), physical properites (crystal form, color, streak, luster, cleavage, luminescence, hardness, density etc.), optical properties (uniaxial or biaxial crystal, positive or negative character, refractive index, reflectance, bireflectance, 2 V , dispersion, absorbability, polychroism etc.), occurrences, paragenetic minerals and references.

Abstract:Microscopic investigation indicate that pyrrhotites in the Meixian and the Qianfeng massive sulfide deposits are mostly synsedimentary in origin and have suffered metamorphism of greenschist facies and deformation of various degrees in the geological history since their fromation. Coating with magnetic colloid has revealed intergrowths of monoclinic pyrrhotite (mpo) within hexagonal pyrrhotite (hpo) grains. These intergrowths include two morphological types: crystallographically controlled lamellar patterns and fissure-and grain boundary-controlled irregular patterns. Lamellar intergrowth of mpo is produced by exsolution from hpo as a consequence of cooling of hpo from emperatures exceeding 254℃, whereas irregular intergrowth results from eplecement of hpo by mpo. The exsolved mpo lamellae have suffered late-stage deformation and metamorphism, resulting in coarsening and homogenization represented by wedge-shaped boundaries, boxwork shapes and complex internal textures. The deformation of sulfide ores in the Qianfeng deposit appears stronger than that in the Meixian deposit, which is evidenced by ubiquitous textures such as subgrains, mechanic twins,kinkbands, and annealing triple junctions and core-mantle assemblages. Mpo lamellae are well preserved in less deformed pyrrhotite either in Meixian or in Qianfeng, but is mostly erased in intensely deformed grains in the Qianfeng deposit, suggesting that anisotropic stress during annealing tends to enhance homogenization of the intergrowths to form uniform hexagonal grains.

Abstract:Tetrahedrite is a common cupreous sulfide mineral in the Ashele volcanic massive sulfide deposit. In the main (No.I) orebody, it is characterized by high As content but low Sb, in No.Ⅱorebody, it is characterized by high Sb content but low As; in both orebodies, it is cha_racterized by high Zn content and insignificant temporal and spatial variations of chemical compositions. Compared with other kinds of ore deposits, zinc_tennantite is a kind of typomorphic mineral in the Altai mineralization province and is useful for the exploration of volcanogenic massive sulfide deposits.

Abstract:The Jianfengling pegmatoid, situated in the upper part of the Jianfengling granite body in Hunan Province, South China, consists mainly of quartz, topaz and zinnwaldite. Three types of inclusions have been found in topaz from the pegmatoid body: (a) silicate melt inclusions, (b) fluid (gas-liquid) inclusions and (c) melt-fluid inclusions. Described here are characteris-tics of these inclusions as well as their distribution, phase state, composition, molecular textures of the polymerized silicate melt, homogenization temperature and homogenizing behavior during the heating, cooling and quenching processes. It is considered that the melt-fluid inclusions are products of random capturing of the unmixed magma (melt) and liquid (fluid) at the end of magmatic evolution. Therefore, the study of melt-fluid inclusions is of great significan- ce in the discussion of the magmatic evolution process.

Abstract:The present paper has described macroscopic and microscopic textures of Dinosaur egg crust fossils. Under microscope and SEM, some tissues and textures of Dinosaur egg crust were observed, such as relic egg crust membrane fabrics, conical layers and prismatic layers. Carbon and oxygen isotopic analysis of Dinosaur egg crust fossil was made, which led to the discovery that carbon isotopes of Dinosaur egg crust fossils are composed of three parts. There exists organic carbon in primary carbonate minerals, secondary carbonate minerals formed in the diagenetic process and organic matter closely related to Dinosaurs; nevertheless, carbon is mainly of inorganic origin.δ13C anomalies are mainly related to diagenetic secondary change. Oxygen isotopes mainly reflect oxygen isotopic composition of underground fluids in the diagenetic process, but have little to do with primary oxygen isotopic composition of Dinosaur egg crust. The richer the heavy oxygen in Dinosaur egg curst fossils, the less these fossils suffered from diagenetic secondary change. Compared with Dinosaur egg crust fossils from Nanxiong Basin, the Dinosaur eggs in Xixia basin experienced much stronger diagenesis. Therefore, if one wants to trace the food type, ecological environment and extinction of Dinosaurs in the light of carbon and oxygen isotopic values of Dinosaur egg crust fossils, he must separate primary carbonate minerals of Dinosaur egg crust fossils from their secondary carbonate minerals and, what is more, isolate organic matter to make carbon and oxygen isotopic studies.