Abstract:With single_zircon evaporation technique, the authors determined207Pb/206Pb age of Nanqiao basalt in Hunan, which is located along the westward extension of ancient Jiuling island arc in northwest Jiangxi. The data yield a zircon crystallization age of 1 271±2 Ma for the basalt. The basalt and diabase show highly depleted geochemical features: K2O values are very low, abundances of their incompatible HFSE and REE are mostly lower than those of N_MORB (with a few close to the latter), andεNd(1 271 Ma)values vary from 6.86 to 8.98, suggesting typical N_MORB geochemical characteristics. This basalt may represent a relict of the ocean crust distributed along an ancient subduction zone and can serve as new evidence for ancient Jiuling island arc.

Abstract:Abstract: The Kalatongke Ni-Cu sulfide deposit is an important Cu-Ni-rich deposit in western China. Geochemical studies of the basic complex closely associated with the deposit show that it is characterized by low Ti, depletion of Nb or Ta and enrichment of LREE and large lithosphile elements. These features, combined with their isotope geochemistry, have led the authors to believe that the magma occurred under an extensional condition following the collision between the Siberian plate and the Junggar plate, and was derived from the depleted asthenospheric mantle, contaminated however by crustal materials within high-level magma chamber. Thus, the addition of crustal silicate material was sufficient to trigger the immiscibility between the sulfides-rich liquid and the silicate-rich liquid.

Abstract:Based on survey and research, the authors have found a suite of Neo-Archaean intrusive rocks composed of plagiogranite, quartz diorites, and diorites in Seerteng area, Inner Mongolia. Isotopic dating of plagiogranite indicates that the age of the rocks is at 2 400~2 500 Ma. According to isotopic age and regional geo- logic characteristics, the authors hold that the intrusive rocks might be products of Neo-Archaean

Abstract:The dacite cropping out at Jilusu on the northern margin of Qaidam basin has lots of adakitic features: SiO263.7%~64.3%, Al2O315.07%~15.27 %, MgO 3.47%~3.72 %, K2O/Na2O ratio is about 0.14~0.25, Y and Yb are both low: Y is 17.82×10-6~18.10×10-6, 17.96×10-6on average, and Yb is 1.47×10-6~1.55×10-6, Sr is high (527×10-6~537×10-6), HREE is depleted and Eu and Sr negative anomalies are relatively weak, but the content of MgO is higher than that of the typical adakite in the world. Generally,the presence of adakite signifies the beginning of slab subduction. The age of adakitic dacite is about 514.2±8.5 Ma, and the age of eclogite from the northern margin of Qaidam basin is 494.6±6.5 Ma. Therefore, it is considered that the slab started its subduction in Late Cambrian, that the adakitic magma was formed at the subduction depth of about 75~85 km, and that the partial melting residues with garnet facies continued subducting and finally formed eclogite in Early Ordovician. The discovery of adakitic dacite confirms that ocean-continent subduction occurred in Early Palaeozoic on the northern margin of Qaidam basin.

Abstract:The recently discovered bedded tuff and tuffaceous sandstone within the Dabeigou Formation in Luanping basin of northernHebei were dated by SHRIMP zircon U-Pb technique at 133.9±2.5 Ma and 130.1±2.5 Ma respectively. The SHRIMP zircon U_Pb age of 135.4±1.6 Ma for the top tufflava of the Zhangjiagou Formation at eastern Jingshang Village was also obtained. A comprehensive study indicates that a complete Jehol biota_bearing succession is deposited in Luanping basin of northernHebei, and that 135 Ma is the lowest chronohorizon from which Jehol biota appeared. The authors hold that the boundary between Dabeigou Formation and Dadianzi Formation is 130 Ma in age, the data is helpful to the study of the boundary between Jurassic and Cretaceous.

Abstract:The basic lavas in Jigen area of southwest Tianshan Mountains occur as lenses or slices within the Pa-leozoic metasediments, with their source magma belonging to the tholeiitic series. The chondrite-normalized REE patterns indicate that they are slightly enriched in LREE. On the other hand, the trace element patterns normalized by MORB or primitive mantle show the enrichment of Th, Nb, Ta, Zr and other HFS elements with the values of Zr/Nb being 10 or so, similar to characteristics of P-type mid-ocean ridge basalts (P-MORB).A Sm-Nd isochron age of 392±15 Ma obtained for the basic lavas is interpreted as their crystallization age. The basic lavas show high positiveεNd(t) values in the range of +4.24 to +6.79, suggesting that the basic lavas were derived from mid-ocean ridge ocean setting. The study of Sr-Nd isotopes show that the source of basic lavas was derived from the N-MORB-like mantle and was affected by the enrichment of the mantle source during their formation processes. Other ophiolite members associated with basic lavas such as gabbro slices and altered ultra-basic rock slices were also found in Jigen area, which represent the remnants of fragmented oceanic crust of the Paleo-South Tianshan ocean. According to the age and sites, it is proposed that the ophiolitic remnants can be correlated with the Late Paleozoic ophiolite belt in south Tianshan Mountains which serves as the boundary b-tween the Tarim Plate and the South Tianshan tectonic belt.

Abstract:The noble gas isotopic and compositional data of alkali basalt, lherzolite xenolith and megacryst clinopyroxene from Kuandian area confirm the opinion that fractionation of noble gases existed during magmatism, and that the lighter noble gases such as He and Ne have much higher mobility and incompatibility than heavier ones like Kr and Xe. Therefore, the lighter noble gases are relatively concentrated in volcanics, especially in volcanics with bubbles, whereas lherzolite xenoliths have quite abundant heavier noble gases. Megacryst clinopyroxene has the lowest abundance of noble gases, probably attributed to its highp-Tgeneration. Noble gas isotopic compositions reveal that the mantle source beneath Kuandian area has an MORB_like reservoir with 3He/4He being 10 Ra (atmospheric3He/4He value) and40Ar/36Ar being 350. Lherzolite xenoliths possess 3He/4He ratios of 2.59~4.53Ra, reflecting their highp_Tdeformation and metasomatism. Volcanics have very low3He/4He ratios (0.47~0.61 Ra), indicating the contribution of radiogenic4He due probably to crust contamination. Most samples show excesses of21Ne and22Ne compared with atmospheric neon, while Kr and Xe isotopic compositions are indistinguishable from atmospheric values with only a few samples showing excesses of129Xe,134Xe and136Xe.

Abstract:There exist two-layer structure" orebodies in the Dapingzhang Cu-polymetallic deposit. Massive sulfide samples from the upper ore bed and veinlet-disseminated sulfide samples from the lower ore canal of the deposit were analyzed for REE contents by ICP-MS. The chondrite-normalized REE patterns of massive sulfide samples are all characterized by positive Eu anomaly, and those of veinlet-disseminated sulfide samples by negative Eu anomaly. The variation of Eu anomaly in sulfides of different mineralized belts can serve as an indicator of the evolutionary character of ore-forming fluids. A comparison with the REE patterns of hydrothermal sediments and black-smoker fluids from the TAG of the mid_Atlantic ridge suggests that metallogenesis of the deposit is related to volcanic-exhalative-sedimentation.

Abstract:Being products of water-rock interaction during the migration of fluids, clay minerals can help us to understand the mechanism of water-rock interaction and features of fluids. With the Jinshan gold deposit in Jiangxi Province as an example, the authors determined the crystallinity, mean crystal size and lattice strain of illite and chlorite and, on such a basis, discussed the difference of crystallinity, mean crystal size and lattice strain between illite and chlorite caused by deformation of mylonite and untramylonite. There exist strong negative correlation between crystal size and crystallinity of illite in altered mylonite of low strain and low water/rocks ratios, and positive correlation between crystal size and crystallinity of chlorite in altered untramylonite of high strain and high water/rocks ratios. From altered mylonite to altered untramylonite, the crystallinity of illite decreases whereas that of chlorite shows no obvious variation with the increasing strain. It is held that the formation of clay minerals is affected not only by water-rock interaction but also by the strain rate and recovery rate during rock deformation. The relationship between crystallinity and crystal size of illite or chlorite can reflect the behavior and mechanism of deformed rock.

Abstract:Based on such analytical means as EMPA, chemical analysis, XRD, IR and LRM, the authors have extensively studied Shoushan Stone from Jialiangshan in Fujian Province. The results show that Shoushan Stone in Jialiangshan area is a kind of rock mainly composed of pyrophyllite, diaspore and quartz. Most of the stones have perfect 2M type of pyrophyllite. The Shoushan Stone in Jialiangshan area was formed by hydrothermal activities and the ore_forming process can be divided obviously into three stages. The metallogenic temperature is about 285~405℃and the ore-forming pressure is lower than 0.26 GPa.

Abstract:Four unusual varieties of Si-Fe alloys occur in ophiolite along the Yarlung Zangbo River. Podiform chromite deposits are distributed in the hurzburgite facies of the Luobusa ophiolite. The Si-Fe alloys are composed chemically of Fe3Si7, Fe7Si3, Fe6Si4, and Fe4Ti3Si2P, and the associated minerals comprising Fe, FeO, SiO2, Si and Mg silicates occur in chromitite. The intergrowth texture formed by 3 alloys indicate that these alloys have same genesis, and the texture developed in the Si-Fe alloys might be a product of chemical reaction between liquid iron and silicate on the boundary of mantle and core.

Abstract:Strontianiferous aragonite occurs at the Yanzidong Cu deposit in the northern part of Lanping basin, Yunnan Province. Examination by such means as X-ray, EMB, test of microhardness and index of refraction together with gemological studies have revealed that this strontianiferous aragonite is a special kind of aragonite, the change of the crystal lattice and genesis of the colour have also been analyzed. In addition, the advantage and possibility of the application of the aragonite as a kind of gem have been studied.

Abstract:Based on a series of experiments, this paper studied the capacity of slag for removal of phosphorus from model wastewater.The results show that slag is effective in adsorbing phosphorus.The factors affecting the removal of phosphorus are the initial phosphorus concentration,pH value,adsorption equilibrium time and the amount of slag.When the concentration of phosphorus is 2~13mg/L,the amount of slag used is 5 g/L,the pH value is neutral, and the adsorption time is 2h,the removal rate of phosphorus can be higher than 99%.

Abstract:Based on crystal structure and crystal chemistry theory, this paper puts forward the minimum dimension of the nano-kaolinite corpuscle. Through calculating the crystal cell number, atomicity and the external atomicity on the (001) crystal plane of kaolinite grains of different granularities, the paper also describes their characteristics, and analyzes their relationship with the specificities of the nano-kaolinite corpuscle.

Abstract:This paper deals with the crystal morphology of ZnAl2O4. Based on the theoretical model that the growth units are polyhedral structure of coordinative anions, the authors studied the growth of ZnAl2O4by formulating the mathematical model and calculating the stability energy of the growth units. It is concluded that the favorable growth unit structure for ZnAl2O4is the regular octahedron.