Abstract:Usually associated with large-scale tectono-magmatic activities, granitoids are widely spread in Beishan area. This paper mainly focuses on the geochronology of the granite in Mingshui area. Based on the40Ar-39Ar isotopic dating of biotite from the granite in Mingshui, the authors obtained a plateau age of 218.4±0.5 Ma, which indicates that the granite in Mingshui must have intruded during the Indosinian movement and might have been produced by eventual collision between the Tarim and the Kazakhstan plates.

Abstract:Indosinian S-type granites are widely distributed in central Inner Mongolia on the northern margin of North China landmass. Spread in nearly EW direction, the granites have formed a gigantic compound granite belt, with porphyritic biotite-admellite and moyite being the two main types. SiO2is abundant, Al2O3is 12.38%~15.34%. A/NKC (molecule ratio)>1.1, K2O/Na2O=1.1~3.1,δ=1.9~2.6,ΣREE is 45.778 ×10-6~486.501×10-6, andδEu=0.1~0.8. A series of zircon U-Pb surface ages (207~227 Ma) for the granites have been recently obtained from 1/50 000 regional geological survey. As the lithofacies and geochemical characteristics of the granites are similar to those of S-type granites, the authors conclude that the Indosinian granite in this area was formed in a post-collision setting instead of in the setting of syn-collision between North China plate and Siberia plate.

Abstract:Baerzhe granite in Inner Mongolia is a rare rock depleted in 18O. This paper gives the oxygen isotopic values of quartz, feldspar, riebeckite, zircon and whole rock of Baerzhe alkali granite, which seem to be the lowest among these isotopic values in all the alkali granites of China. In the light of isotopic data, this paper deals with geological and geochemical characteristics, the origins of Baerzhe rock body and the 18O-low alkali granites in eastern China. The authors consider that two arguments are relatively reasonable for illustrating the petrogenesis: one is isotope exchange between the rock and the meteoric water, and the other is magmatic degassing of the rock in an open system. The problem of petrogenesis deserves further researches.

Abstract:Jingdingshan volcanic rocks occur in the eastern part of West Kunlun Mountain in North Tibet Plateau, geotectonically on the southern margin of the suture zone between North China plate and South China plate. The rocks originated from typical continental central eruption characterized by more than three times of volcanic activities. They overlie abruptly declining Palaeogene Aletars Formation (E3a) in the form of gentle la-va sheet and have been subjected to slight erosion. K_Ar isotopic age is 0.45~1.93 Ma. Latite, the main vol-canic rock, is of calc-alkaline series in the sub-alkaline series: SiO257.88%~60.82%, MgO 1.95%~2.2%,Na2O+K2O 6.93%~7.27%,δ2.73~3.1, andDI63.5~64.6. The large_ion lithophile elements are highly concentrated, while the high_field intensity elements are comparatively less concentrated. REE 650×10-6~766×10-6and LREE/HREE 14.9~15.7 point to intensely-concentrated LREE.δEu values are 0.75~0.89,(87Sr/86Sr) is 0.70970 andδ18O is 10.4‰. A comprehensive study shows that the magma came from partly, melting magma in the lower crust or the transitional zone between the crust and the mantle, whereas the vol-canic rocks were formed in a post-collision uplifted extensional setting.

Abstract:Based on the study of the felsic volcanics in Xia' nanggou district of Yidun island arc, the authors identified for the first time an intraplate volcanics belt in the back_arc region of the arc. These volcanic rocks are shoshonitic series and are geochemically characterised by K2O-, Nb-, Ta-, Zr-, Hf-enrichment and CaO-, Sr-, Eu-depletion. They have a common V-type" REE chondrite-normalized pattern. Their Pearce' s tectonic discrimination diagrams indicate a clear intraplate rifting formation setting. Four bulk-rock samples give a good Rb-Sr isochron witht=189.2±5 Ma, R=0.999 824, andISr=0.714 578. The chemical variation of the volcanics are controlled by both residual of plagioclase in the melting source area and crystal fractionation of biotite after magma formation. Considering the 213 Ma formation age of the Miange Formation bimodal volcanics in the back_arc basin east of the intraplate volcanic rock belt, it is held that the island arc completed the important transition from subduction arc-forming to intraplate rifting regime only within a period of 24 Ma, from which exact constraints on the arc evolution sequence have been obtained.

Abstract:Based on seismic survey, well logging and core observation, this paper interprets the sublacustrine fan of Liushagang Formation in Fushan depression. The formation of the sublauctrine fun can be attributed to two factors: the main factor is that the front of the delta entered the deep lake area along the southern slope under the action of the gravity. The second factor is that the channel sand close to the steep margin of the basin entered the deep lake area along the underwater channel, forming the gravity flow sedimentary underwater. Due to the different tectonic backgrounds and the degrees of material supply, the sublacustrine fan was mainly distributed in L1 and L2 periods, but was not well developed during L3 period. Viewed from spatial distribution, the sublacustrine fan was mainly developed in the northern and western parts, and the eastern part only possesses the secondary importance in this aspect. The extent of the fan in the north and the west is greater than that in the east, and the duration of the fan in the north and the west is also longer than that in the east. At the surface, the sublacustrine fan is distributed on the outer edge of the delta regime, and the sedimentary evolutionary sequence is in upward succession from sublacustrine fan through distal end of delta front to proximal end of delta front. The general sedimentary model of sublacustrine fan is like this: abundant braided delta sandstone migrated from the south to the north, deposited in the deep lake, and formed an isolated and big sublacustrine sandbody. The secondary material sources from the west and the east formed the sublacustrine fan in the deep lake under the control of the main active faults in the east and the west.

Abstract:Based on Pb isotopic data of volcanic rocks from the middle part of Sanjiang ( Nujiang, Lancangjiang and Jinshajiang) and adjacent areas, the authors have determined the Pb isotopic geochemical boundary between Yangtze and Gondwana continental blocks in the middle part of Sanjiang region, southwestern China. The geochemical boundary has the values of 206Pb/204Pb = 18.583, 208Pb/204Pb = 38.575 and V1 = 60, V2 = 52. Compared with standard geochemical boundary values, Yangtze and Gangwana blocks have lower and higher values, respectively. The Pb isotopic geochemical boundary separates Yangtze block in the east from Gangwana block in the west, it corresponds to Luchun-Hongponiuchang belt geographically, to Deqin-Ziga fault tectonically, to the boundary between Jinshajiang and Lancangjiang in terms of tectonic-magmatic belt, and to the Yangla-Luchun-Hongponiuchang polymetallic ore-forming belt metallogenetically.

Abstract:This paper deals with the main transformation directions and the affecting factors of kaolinite as well as the main composition of tonstein by studying the petromineralogical features of tonstein intercalations in the anthracite bed. A series of means, such as microscopic identification, differential thermogram analysis, X_ray powder diffraction analysis, infrared absorption spectrum analysis, were used to study the samples collected from the working field. The research results suggest that kaolinite is transformed toward illite, accompanied by the appearance of I/M and montmorillonite. The heightening of the metamorphic grade of coal and the transformation of its sloam are attributed to the action of regional metamorphism and the influence of the surrounding media conditions.

Abstract:A kind of unnamed Ir_Fe_Ni alloy was found in chromite of Luobusa ophiolite in Tibet.EPMA shows that its molecular formula is Ir0.69Fe0.28Ni0.03, and the powder X-ray diffraction data, measured by SMART APEX-CCD system, are shown as follows (inside the parentheses isI/Io): 2.188(100),1.896(90),1.347(50),1.149(80),1.096(15),0.949(5),0.874(15),0.852(15),0.773(10). According to the powder diffraction data, the crystal structure of the alloy belongs to the face-centered cubic kind of metal element. The atom coordinates are determined and the theoretical powder diffraction pattern is calculated according to the structure model. The results show that the theoretical powder diffraction pattern is basically consistent with the observable data. The crystallographic data of Ir-Fe-Ni alloy can be summed up as follows:a=3.802(4) ,space group:Fm3m,the number of molecules in unit cellZ=4,Dc =13.84 g/cm3。

Abstract:The retrograde metamorphism of eclogites in Dabieshan area can be divided into fluid-poor, fluid-bearing and fluid_rich stages. Recrystallization, polymorphous conversion and exsolution of rock_forming minerals of the eclogites seem to have been the main processes of the fluid-poor stage. The fluid_bearing stage proceeded at high temperatures and pressures, and is characterized by the participation of minor fluids. White mica formed at this stage is dominated by phengite. Due to the participation of large quantities of fluids, the fluid_rich stage is characterized by the formation of various low-pressure and hydrous minerals including a variety of white micas. White mica formed at earlier fluid_rich stage is dominantly phengite, with atom number of Si varying between 6.5 and 7.2 pfu. White mica of the late fluid_rich stage is markedly variable in composition, consisting of paragonite, muscovite and margarite. Biotite is the last kind of mica formed in the process of diaphthoresis. Also studied in this paper is a zoned structure of retrograde mica, which consists of an inner zone of paragonite, an intermediate zone of muscovite-margarite intergrowths and an outer zone of biotite.

Abstract:According to the redox environmental property of cryptomelane, the phenol degradation in aqueous and acidified suspensions by native cryptomelane has been studied. The results are as follows: First, the degradation rate of 50 mL phenol solution whose concentration is 100 mg/L can almost be up to 100% when pH is 2.1, quantity of mineral is 10 mg/L, grain size of mineral is 160~200 mesh, temperature is 25℃, buffeting speed is 200r/min, and time is 8h. Second, illumination and oxygen don' t affect the degradation of phenol. Third, the reaction rate increases when pH decreases. Fourth, the reaction is most likely to take place when the grain size is relatively small while the quantity of mineral, temperature and buffeting speed are comparatively high. Besides, sodium chloride or calcium chloride doesn' t affect degradation of phenol, and degradation rate decreases when sodium phosphate or sodium acetate is added to the reaction solution. It has been deduced from the products that degradation of phenol is attributed to the oxidation of cryptomelane. This is an effective method to degrade phenol sewage. This study will extend the application range of cryptomelane.

Abstract:The potassium feldspar powder with high concentration of Fe2O3 was obtained by pretreating the potassium_rich shale from Jiangsu Province and used as the main starting materials. 13X zeolites were synthesized by baking and hydrothermally synthesizing procedures. The optimal technical parameters were determined by means of quadrature experiments. The properties of the synthetic zeolite are similar to those of the industrial 13X zeolite and its absorbability meets the state standards of chemical industry of China. The synthetic zeolite can be used to treat the waste water with heavy metal cations.

Abstract:Mineral_bound humic substances can modify the surfaces of minerals. The intensity of humic acid sorption on kaolinite, gibbsite and quartz is related to the nature and number of adsorption site of the minerals, the electricity and the specific surface. Calculated by the specific surface, the capability of minerals for humic acid sorption follows the sequence gibbsite>kaolinite>quartz; calculated by per unit mass of minerals, the sequence is kaolinite >gibbsite >quartz. It is thus considered that the mechanism of humic acid sorption on the minerals is affected significantly by pH value of the solution. Under the condition that pH values of the solution range from 4 to 7, the model for humic acid sorption on minerals can be described as follows: the hydrogen bonding is the main sorption form of quartz; the ligand exchange surface complexing is the main sorption form of gibbsite; and kaolinite is characterized by the existence of multiple sorption forms such as the hydrogen bonding, the ligand exchange surface complexing, the hydrophobic interaction and the cation bridging.

Abstract:The micromorphology of quartz crystals formed at different ore_forming stages in auriferous quartz veins are studied by means of differential interference microscope. The micromorphologic characteristics of quartz crystal faces of {1011},{0111} and {1010}help to understand the mechanism and the rate of crystal growth, the oversaturation of ore-forming solution, and the variation of the growth environment, and can also provide information for the division of ore_forming stages and the thermodynamic condition for crystal growth.

Abstract:Nano-scale science and technology has achieved great successes in the field of eart sciences. Mineralogy is a major basic science in earth sciences and clay mineralogy occupies an important place in material science. It seems necessary to set up the subject of nano-scale clay mineralogy". The research method of nano-scale clay mineralogy is consistent with nano_scale science and technology, whereas the research content of nano-scale clay mineralogy consists of particle mineralogy, physics, chemistry, material science and processing technology. This paper deals further with the detection method and the analytical standard of nano-scale clay mineral as well as the industrial production of the compound polymer/nano-scale clay mineral material.